WO1995024822A2 - Multi fluid, reversible regeneration heating, combined cycle - Google Patents

Description

MULTI FLUID, REVERSIBLE REGENERATION HEATING, COMBINED CYCLE

BACKGROUND OF THE INVENTION

Field of the Invention : This invention pertains to thermal power plants, in particular to power plant cycles to impose HEAT TRANSFER REVERSIBILITY, between various fluids, and more precisely to heat transfer in regenerative heating of working fluid streams.

Description of the Prior Art : The invention pertains to power cycles wherein heat energy is converted to mechanical energy through the use of an intermediate fluid, known as working fluid. Two main forms of power cycle are Rankine Cycle, and Brayton Cycle.

In Rankine Cycle, steam (water) is working fluid, which goes through a phase change. Heat energy is transferred to working fluid indirectly i.e. there is no direct contact between the heat source, and working fluid. The compression work of pump (negative work) is performed on liquid (water), and the expansion work of turbine (positive work) is performed by gas (steam), thereby resulting in a net work output for the cycle. Phase change in a condenser, results in considerable latent heat loss into river water. Several variations to improve thermal efficiency are, regenerative heating of liquid feedstrea , or working fluid, and reheat of the partially expanded steam in Rankine Cycle.

In Brayton Cycle, products of combustion, i.e. flue gas is used as working fluid. There is no phase change, and the cycle works between suitable temperature, and pressure, and uses the atmospheric pressure discharge to complete the cycle. Heat energy is introduced via direct combustion. Working fluid, i.e. products of combustion expand at a very high temperature to yield net work output.

In order to enhance thermal efficiency, in one arrangement, the two cycles are integrated, wherein the WASTE HEAT from

Brayton- Cycle, is used for Rankine Cycle. This arrangement is commonly known as combined cycle. Several other cycles are being developed, without much departure from the basic approach. One cycle, which uses a radical departure from the conventional approach, uses ammonia/water PHYSICAL mixture, as working fluid.

SUMMARY AND OBJECTS OF THE INVENTION

The invention pertains to recognition of the principle of heat transfer reversibility as an important thermodynamic tool. In the evolutionary development of thermal cycles, HEAT TRANSFER REVERSIBILITY was seriously overlooked, as a thermodynamic principle to design an ideal cycle. One such place of oversight is in feedstream heating in Rankine Cycle. A large proportion of regenerative heat energy, is derived from the latent heat of bleed stream, which, inherently, does not permit REVERSIBLE heat transfer. This is because latent heat of condensation takes place at CONSTANT temperature i.e. NO temperature change across heat transfer process. Thus, matching heat capacities, i.e. product of mass, and average specific heats is not possible. This will be discussed in more detail later in the speci ication.

After clear, and thorough understanding of heat transfer reversibility, AND means, and hardware developed to apply this principle, a number of cycle configura ions are discussed, using a multitude of working fluids. This results in combined cycle configurations. When it is recognized that IMPOSITION of heat transfer reversibility presents technological challenges, innovative hardware to SUPPORT the ideal cycle, thus developed, is shown. Thus the COMMON thread through the entire discussion is HEAT TRANSFER REVERSIBILITY, as applied to heat transfer in the regenerative, as well as throttle feedstream heating.

In certain cases, two streams of the same fluid, heated in different parts of the cycle, will be involved in "mixing." In the design of the cycle, these streams, if having the ability to be heated to a common temperature, are heated such, to

IMPOSE REVERSIBILITY in the MIXING process. Thus a thermodynamically ideal cycle is the objective, based upon these two criteria.

BRIEF DESCRIPTION OF THE DRAWINGS

Invention is best understood from the following drawings : Fig 1A shows a multi fluid cycle using indirect heating. Fig IB shows a multi-fluid cycle using premium uel. Fig 1C shows a multi-fluid cycle using indirect heating. Fig 2A shows controls to match heat capacities. Fig 2B shows the effect of various heat capacities. Fig 2C shows comparing heat capacities in the air heater. Fig 2D shows heat capacities for condensing fluids. Fig 2E shows heat transfer for subcritical pressure. ig 2F shows the temperature/sur ace relation for above. ig 2G shows the temperature/sur ace relation. ig 2H shows matching heat capacities. ig 21 shows matching heat capacity for multi-fluids . ig 2J shows matching heat capacity for mul i-fluids . ig 2K shows U-tube heat exchanger for matching heat capacity. ig 3A shows an expansion line for supercritical pressure. ig 3B shows the devices for the above. ig 3C shows an expansion line for supercritical pressure. ig 3D shows the devices for the above. ig 3E shows an expansion line for superc itical pressure. ig 3F shows devices for the above. ig 3G shows the ammonia/water combined cycle. ig 3H shows the multi stage reversible combined cycle. ig 4A shows the use of ejector. ig 4B shows the benefits of using ejector. ig 4C shows the theory behind the design of ejectors. ig 4D shows the devices for the above. ig 4E shows an innovative "smart" ejector. ig 4F shows a double wall ejector for high temperature use. ig 4G shows the use of ejectors to divert a fluid flow. ig 4H shows multi fluid source ejector. ig 5A shows a design for shell and tube heat exchanger. ig 5B shows a design for boiler pressure parts. ig 5C shows components for very high temperature/pressure. ig 5D shows a free standing tube arrangement. Fig 5E shows the end connection for above.

Fig 6A shows the heat transfer surface arrangement in a boiler

Fig 6B shows the heat transfer surface for air cycle.

Fig 7A shows a positive displacement pump using linear motor.

Fig 7B shows the above with mechanical drive.

Fig 7C shows a pressurized enclosure for high pressure cycles.

Fig 7D shows a high pressure turbine without control valve.

Fig 8A shows a truncated expansion line for gas turbine.

Fig 8B shows the devices for the above.

Fig 8C shows a truncated expansion line and reheats.

Fig 8D shows the devices for the above.

Fig 8E shows a truncated gas turbine with reheat.

Fig 8F shows the use of innovative ejectors.

Fig 8G shows expansion line for multi recuperator arrangement.

Fig 8H shows devices for the above.

Fig 9A shows the bottoming subatmospheric pressure cycle.

Fig 9B shows innovative ejector and compressed air storage.

Fig 9C shows the use of compressed air for cooling.

Fig 9D shows a composite cycle based upon above.

Fig 10A shows the expansion line for a once through cycle.

Fig 10B shows the devices for the above.

Fig IOC shows the diversion of products of combustion.

Fig HA shows a subatmospheric pressure air cycle.

Fig 11B shows a subatmospheric pressure air cycle.

Fig 11C shows a piston arrangement for flue gas use.

Fig 11D shows a pressurized air cycle with indirect heating.

Fig HE shows a combined subatmospheric pressure air cycle.

Fig 11F shows the indirect heat transfer with gas turbine.

Fig 12A shows a multi-fluid cycle.

Fig 12B shows a multi-fluid cycle steam as heat transport loop.

Fig 12C shows a water/ammonia cycle with truncated turbine.

Fig 12D shows a water/ammonia cycle with truncated water cycle.

Fig 12E shows a reversible, regenerative heating cycle.

Fig 12F shows a subcritical/supercritical pressure cycle.

Fig 12G shows the matching heat capacities in heat exchanger.

Fig 12H shows expansion line for high temperature reheat cycle.

Fig 121 shows the use of an innovative ejector.

Fig 12J shows carbon dioxide/carbon dioxide multi-fluid cycle.

Fig 12K shows a carbon dioxide truncated/carbon dioxide cycle.

Fig 12L shows a multi stage reversible feedstream heating.

Fig 13A shows a subcritical pressure heating stage. Fig L3B shows a subcritical pressure cycle with combustion air

Fig 13C shows a combustion air heating arrangement.

Fig : L3D shows combustion air heating for start up/part load.

Fig . L3E shows the reversible flue gas cooling.

Fig : L3F shows the use of heat exchanger for cooling flue gas.

Fig : L3G shows a composite cycle for subcritical pressure.

Fig 3 L3H shows the component layout for the above.

Fig : L3I shows the reversible matching of heat capacity.

Fig 1 L3J shows the use of bleed stream superheat thermal energy.

Fig 3 L3K shows the use of bleed stream superheat thermal energy,

Fig 3 L3L shows the use of bleed stream superheat thermal energy.

Fig 3 L3M shows the use of bleed stream superheat thermal energy.

Fig 3 L3N shows the expansion line for subcritical pressure.

Fig 3 L30 shows the devices for the above.

Fig 3 L3P shows devices for high temperature multi-reheat cycle.

Fig 3 L3Q shows variations to the above by applying teachings.

Fig 3 4A shows the heating of boiler superheater sprays.

Fig 3 L4B shows an improved boiler blow down system.

Fig 3 4C shows a passive cooling system for the boiler drum.

Fig 3 L4D shows boiler feedwater pump recirculat ion system.

Fig 3 4E shows the steam dumps/non condensables system.

Fig 3 L4F hows the repair in place of feedwater heater.

Fig 3 4G shows boiler recirculat 1on system.

Fig 3 4H shows the deaerator heater without storage tank.

Fig 3 41 shows thermal energy storage for peak load.

Fig 3 4J shows air enrichment method.

Fig 3 5A shows a repowering arrangement with gas turbine.

Fig 3 5B shows an indirectly heated gas turbine repowering.

Fig 1 5C shows truncated gas turbine for repowering.

Fig 3 6A shows reheater drains from a steam to steam reheater.

Fig J 6B shows power degradation recovery for summer operation.

Fig 3 7A shows the use of ejector for part load application.

Fig 1 7B shows the use of ejector in replacing steam turbine.

Fig 3 7C shows the use of ejector in a gas turbine application.

Fig 1 7D shows the use of ejector in air cycle application.

Fig 3 7E shows the use of ejector for combined cycles.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As the invention pertains to conversion of thermal energy into propulsive power, a discussion of the types and ranking of thermal energy will be appropriate as below. PRIMARY HEAT : This is the highest form of thermal energy, in a cycle, and the most desirable form, such as the fuel heat.

SECONDARY HEAT : This is primarily the bleed stream thermal energy. This heat source, has done SOME useful work, and can do even MORE work, if PERMITTED to continue to expand. However, it is more beneficial, in the overall scheme of things, that this (fluid) be used to heat feedstream, instead. This in turn will reduce the requirement for PRIMARY HEAT, at some work penalty, with NET efficiency gain.

WASTE HEAT : This is the lowest form of thermal energy, which has to be discarded to the environment via river water. Use of this thermal energy is net gain, such as to prewarm combustion air in very cold climates.

The additional terms, for future use, are THERMAL ENERGY PROVIDER, and THERMAL ENERGY RECEIVER; as below:

THERMAL ENERGY PROVIDERS : Fuel heat (through combustion process), bleed steam (or stream) superheat; Bleed stream latent heat as well as sensible heat (of liquid drains), boiler blow down stream, flue gases in the boiler, as well as leaving the boiler (economizer), exhaust stream into the condenser, hot reheat etc. THERMAL ENERGY PROVIDERS are fluid streams, that are cooled as part of power cycle.

THERMAL ENERGY RECEIVERS : Condensate, feedstream, combustion air, compressed air in gas turbine cycles, cold reheat, fuel stream, gas/fuel oil etc., representing the sensible heating energy, and NOT the combustion energy. THERMAL ENERGY RECEIVERS are fluid streams that are heated as part of the cycle.

An important building block is the heat transfer reversibility, which, for this specification, is that when TWO fluid streams are involved in a HEAT EXCHANGE process, the temperature RISE of one EQUALS the temperature DROP in the other, regardless of the TERMINAL TEMPERATURE DIFFERENCE. The heat capacities of the two fluid streams, are thus equal. OR the product of mass flow rate, and average specific heat for the two fluid streams is equal.

Multi working fluid cycles are coupled thermodynamically by INDIRECT heat transfer, in a reversible manner, without PHYSICAL "mixing." Heat transfer reversibility is imposed in feedstream heating by:

(a) for non condensing fluids, matching heat capacities, through modulation;

(b) for condensing fluid(s), matching heat capacities, by properly sizing heat exchanger; AND by keeping the THERMAL ENERGY PROVIDER above critical pressure, and THERMAL ENERGY RECEIVER in liquid form only, EXCEPT when it is also at above critical pressure; i.e. ONLY SENSIBLE heat transfer between fluid streams. Further discussion on heat transfer reversibility will be under Figs 2A, 2B ...etc.

Various Figs will have several similar components as part of the composite cycle. These are shown by common designation, to aid in understanding the technology, such as a) Heat Exchangers with reversible heat transfer as "R; " b) Pumps as "P; " c) A WASTE heat condenser is shown such as 65/66/67 in Fig 1A; d) Heat addition is shown such as a "square" 165 in Fig 3H; e) A control signal as dotted line, with a "dot" at the end, such as line 43 in Fig 7B; f) a load, such as shown by a "square" attached to a turbine 308, in Fig 1A; h) a blower as "B; " i) fans, such as induced draft, and forced draft, as "F."

Fig 1A shows a composite cycle using three working fluids. Primary heat source is a boiler 99 in which fossil fuel is used. Topping cycle is a relatively low pressure, indirectly heated air cycle. Ambient air stream 1 is delivered as compressed air stream 2 via a compressor 311. Stream 2 is divided into streams 3, and 4. Flow in streams 4, and 15 is designed to impose heat transfer reversibility. Stream 3 is heated in a heat exchanger 129 using above critical pressure steam, stream 29. The heated stream 6 is now combined with stream 4 at a point 20 where the temperatures of streams 21, and 6 are equal; ensuring reversibility in the "mixing" process. The combined stream 5, is working fluid for the topping air cycle, which enters an air turbine 315, and expanded only partially. Stream 7 is used to drive an intermediate water cycle. A pressurized recuperator 107 conducts a reversible heat transfer between streams 7, and 24. Relatively cooler stream 8 expands in a post recuperator turbine 308 to yield an even cooler stream 9. Excess air stream 11, if any, is discharged to the atmosphere. Stream 10, after being heated as stream 12, is used as combustion air for a boiler 99, with fuel 13, and products of combustion stream 14, as shown.

For the steam cycle, a stream 25 is at substantially above critical pressure, and very high temperature. This stream is motivating fluid for a topping innovative ejector 126. The innovative ejector uses a stream 26 as induced fluid to yield working fluid for a steam turbine 327, which has above critical back pressure. Stream 30 "drives" a bottoming ammonia cycle, in a heat exchanger 130. Similarly, stream 31 is used for the reheat of the ammonia cycle in a heat exchanger 131.

Ammonia cycle starts at a hot well 50. A turbine 358 has above critical back pressure in streams 59, 62. A pump 251 delivers a stream 52, which is passed through a desuperheater 152 to utilize the superheat of stream 64. Stream 54 is heated in a heat exchanger 154, by a stream 59. Stream 60 is pumped forward by pump 260. Streams 61, and 53 are combined. Stream 55 is heated in a heat exchanger 130. Stream 56 is at very high temperature, and pressure. A topping innovative ejector with motivating fluid stream 56, combines with the diverted induced fluid stream 57. Combined stream 58 is working fluid for a turbine 358. A reheater 131, hot reheat 63, and a reheat turbine 363 complete the cycle.

The liquid drains 228, 229, 230, and 231 are from the water cycle. A hot well 20 is the water source for the intermediate water cycle. A pump 222, a discharge line 23, heated by the suction side stream 21, is as shown. A stream 24 enters a heat exchanger 107 to continue the water cycle.

Flue gas stream 15 leaves the boiler. This stream, if not cold enough to be discharged directly into the atmosphere, is cooled further. An induced draft fan 319, draws suction via a line 19. The flue gas stream 15 is cooled in one or more of the three heat exchangers 116, 117, 118 with cooling streams 416, 417, and 418 respectively. These streams are diverted from point 52 in the ammonia cycle, or from combustion air stream 10. Cooling of stream 15 will be required only when the pressure, and therefore the temperature, at point 4 is too high. However, for a relatively lower pressure topping air cycle, the additional cooling of stream 15 is not be necessary.

Fig B shows a three loop cycle, as applicable to a gas turbine based system. A compressor 301 draws ambient air 1, and delivers stream 2 at about 250 psi, which is heated with an above critical pressure stream 12. A heated stream 3 enters a combustor 131, and fuel stream 31 produces a working fluid stream 32 at about 2250 Deg. F. A stream 4 from a TRUNCATED gas turbine 303, is still at a pressure of about 80 psi. Higher grade thermal energy is thus used in a pressurized recuperator

104. A cooler stream 5 enters A gas turbine 305 to complete the expansion. A stream 6, will thus be cooler, than the corresponding final exhaust stream in the present technology.

The pressurized recuperator 104 also results in better heat transfer between streams 104, and 443. The water stream 443, at above critical pressure, is the heat sink for the pressurized recuperator of the topping gas cycle. The working fluid stream

10 expands in a steam turbine 310, with back pressure stream 11 at above critical pressure. A stream 12 is used to preheat stream 2 of the gas turbine cycle. Streams 13, and 14, at above critical pressure "drive" an ammonia cycle. All the liquid drains collect in a tank 116, to complete the cycle.

Ammonia cycle starts at a hot well 20. A turbine 328 has above critical pressure back pressure at streams 29/32. A pump 221 draws suction 21, and a stream 22 is heated by the superheat thermal energy of a stream 31 in a heat exchanger 122. Stream 23 also serves as the cooling loop for the water cycle, which removes heat from the suction side of the pump 241, via a heat exchanger as shown, and delivers it to the discharge line 42 via heat exchanger 142. As an alternate, thermal energy is transferred from the hot stream 115 to cold stream 43 via an intermediate heat transfer loop 70. 71, 72, 73, and heat exchangers 172, 173. A pump 270, using Dowtherm or other fluid thus allows retention of the high grade thermal energy in the cycle, as well as yields cooler, manageable suction temperature for pump 241. A heat exchanger 171 transfers excess thermal energy to a stream 75 for other uses. The excess thermal energy is due to different heat capacities for streams 115, and 43.

Stream 25 continues in the ammonia cycle, and a water stream 43/443 completes the water cycle. Stream 26 is heated in a heat exchanger 132. Stream 27 is heated in a heat exchanger 127 by a stream 13. Stream 28 enters the turbine 328. Stream 32 provides reversible regeneration heating stream in a heat exchanger 132. Stream 29 is reheated by the stream 14 in a heat exchanger 129. Stream 30 expands in a turbine 330. An exhaust stream 31 at about 200 psi, saturation temperature of about 100 Deg. F, discharges into a condenser, with circulating water stream 990.

Fig IC shows a composite cycle with variations to the cycle of Fig 1A. The topping air cycle is subatmospher ic, henceforth called a PULL THROUGH CYCLE. In this case, the compressor is on the outlet or the tail end of the cycle, rather than on the front end, as in a pressurized Brayton cycle. Hence the name.

Ambient air 1 is moved through the cycle via a blower 311. Flue gas stream 20/21/22, and an induced draft fan 322 are shown. A stream 2 is preheated in a heat exchanger 102. Stream 4 is heated in a boiler 99, and a diverted stream 11 is heated by above critical pressure bleed stream 40. Stream 5 completes the air cycle as 5, 6, ...9. A stream 89 discharges excess combustion air, if any, from the cycle. Pressure at 6 is subatmospheric. A heat exchanger 107 represents external cooling .

Steam cycle is "driven" by a heat exchanger 227. A stream 28 is conducted to a turbine train 328/329/330, with above critical back pressure at stream 29. Stream 31/33/34/35 completes the cycle. A stream 32 provides heating steam, to heat air in heat exchangers 109, and 111. Fuel 1110, and a boiler 99 is shown with flue gas stream 110. A stream 30 is used for reheat of a stream 33. Various liquid drains from the water cycle are pumped forward, by pumps 245, and 202, with a combined stream 27. The stream 27 is NOT being heated, so as to provide a low temperature heat sink for stream 6 of the pull- through cycle.

The composite cycles above are coupled thermodynamically. Reversibility in feedstream heating was the underlying approach. It will now be beneficial to go over some building blocks to assist in the subsequent discussion of other cycle configurations, based upon the teachings.

Fig 2A shows controls in order to impose heat transfer reversibility. Fluids A, and B, shown by streams 1, and 2 respectively, exchange ONLY sensible heat, and NOT latent heat, via a heat exchanger 3, having temperature comparators 6, and 7 at each end. Input from temperature comparators 6, 7 "drives" a temperature comparator 4, which in turn, modulates a stream 1, via a control valve 5. The system is thus designed to equate the terminal temperature difference for the heat exchanger 3, thereby equating heat capacities for the two streams. This is the condition for heat transfer reversibility. Other temperatures can be compared, and/or flow rate controls can be devised, to equate heat capacities, based upon teachings. Thus variations to the above arrangement, such as, which of the two streams is modulated; and which two temperatures are compared are considered, to optimize the design. The objective is to vary the mass flow rate of one of the streams, in order to compensate for the differences in the specific heats of the two fluid streams, in order to EQUATE HEAT CAPACITIES of the two streams .

Fig 2B shows several heat transfer schemes to better understand the heat transfer reversibility. In heat exchanger "A" hot stream has higher heat capacity than cold stream. In heat exchanger "B" heat capacity for hot stream is lesser than heat capacity for cold stream. The difference between the two cases is shown by the 0 deg. F terminal temperature difference on different ends, for an infinite surface heat exchanger. In heat exchanger "C" the heat capacities of the two streams is equal. Notice the 0 deg. F terminal temperature difference at both ends, for an infinite surface heat exchanger. In heat exchanger "D" the heat transfer surface is finite, and the heat capacities of the two streams is equal, thereby resulting in parallel lines as shown. In heat exchangers "E" and "F" unequal heat capacities, and finite heat transfer surface is shown, based upon different heat capacities, for hot or cold streams. Notice the different magnitude of the terminal temperature difference in these two cases. In order to impose heat transfer rever ibility, heat capacities of the two streams is equalled by modulation as discussed earlier.

Fig 2C shows an air heater arrangement, with infinite heat transfer surface, for heat exchangers "A" and "C" for simplicity. The ambient air is at 50 Deg. F, and a heat exchanger 77, functionally same, in the combustion air streams of all cases, represents heating by bleed stream. In heater "A," when the heat capacity of the two fluid streams is NOT equal, the heat transfer reversibility CANNOT be adhered to. In this case, the 100 Deg. F worth of excess energy appears as low grade thermal energy in a stream 4. This low grade energy has no useful purpose in a power plant system. However, in air heater "C, " when heat transfer reversibility IS IMPOSED, a slip stream 34 at 600 deg. F emerges, with useful, high grade thermal energy. Combustion air in BOTH the cases is still being heated to 600 deg. F, at streams 2, and 22. The slip stream 34, thus has useful HIGH grade thermal energy, and is used to heat condensate, feedwater streams in a reversible manner. The conclusion above applies for finite heat exchanger surface as well. Other heat exchangers, "D, " "E" and "F" will be discussed under Fig 131.

Fig 2D, for condensing fluids, is shown in an exaggerated manner. Here, a 0 deg. F temperature terminal difference for heat exchange is assumed, to simplify the discussion. Liquid stream 2 at higher pressure, has smaller heat capacity than gas stream 5 at a lower pressure. Process 1/2 represents pumping, and process 4/5 is expansion through a turbine. Enthalpy drops

7, and 8 represent THERMAL ENERGY PROVIDER, and THERMAL ENERGY RECEIVER. Thus, suitable mass flow adjustment will be REQUIRED to equate the heat capacities, so that HEAT TRANSFER REVERSIBILITY can be imposed; process {(2/3) VS (5/6)}.

Fig 2E shows heat transfer when condensing steam at subcritical pressure is the heat source. Bleed stream 1 is conducted into a three zone feedwater heater 8. The system has feedwater streams 5/6, liquid drain level 3, via a tank 4, with level controls (not shown). The condensing zone is 3/7, with remainder of the heater as the desuperheat ing zone. Heat transfer reversibility CANNOT be imposed because LATENT heat in bleed stream 1, determines the rate of flow drawn into heater

8. The accompanied superheat thermal energy only raises the feedwater temperature by matching the energy content, and not heat capacity.

Fig 2F shows the temperature vs surface diagram corresponding to Fig 2E. The presence of LATENT heat does not permit heat transfer reversibility, between bleed stream, and feedwater stream. The latent heat portion of heat transfer 7/3 is worth notice. In this case, 7/3 heat source is at constant temperature. However, temperature profile of the feedwater stream, along 3'/7' is at varying temperature. Thus lines 7/3, and 3'/7' cannot be paralleled.

Fig 2G shows the temperature, surface diagram for heat transfer for above critical pressure application. Streams 5, and 1 are engaged in reversible heat transfer. The water to steam interface is shown at points 6, 7, and 2, 3. The dotted line 3/31 represents non reversible heat transfer, in drain cooling zone of the heater. However, for maximum gain, heat transfer reversibility for the entire heat exchange process must be imposed. Since BOTH the fluid streams are at above critical pressure, heat transfer reversibility can be realized.

However, heat transfer reversibility can still be imposed when stream 5 is at subcritical pressure, PROVIDED, there is no

PHASE change, i.e. stream 8 remains liquid.

Fig 2H shows a design arrangement that MUST be adhered to for heat transfer reversibility. Steam stream 1 enters a turbine 2, and exhaust stream 3 is at above critical pressure. Level control in a heater 4 is maintained so that there is NO drain cooling zone. Saturated drains 7 are conducted into a tank 8 via line 7, and, level in the tank is maintained by a throttling valve 11, and a level control system 9. As can be observed, the heat transfer between 3/7, and 5/6 is NOT reversible. In the lower heat exchanger 41, a properly designed level control system, will yield reversible heat transfer. The nodes are similar in the two heat exchangers, and can be understood from the above discussion. Level 90 is steam/water interface on the shell side. Similarly, level 991 pertains to the tube side. It must be pointed out that for a practical design, the temperature at 92 is higher than the temperature at 93. Thus, there will NOT be reversible "mixing" at point 112. However, heat transfer reversibility MUST be IMPOSED between streams 51, and 94. A 100 deg. F terminal temperature difference is used to better understand the system. Heat transfer reversibility is IMPOSED, by proper sizing of the heat transfer surface. An equalizing line 900 is for level control design. A multitude of floats 992, of suitable cross section, are shown. This will eliminate direct steam to liquid contact, and thus MINIMIZE heat transfer between the 1000 deg. F steam in line 900, and the 200 deg. F water surface 991.

Fig 21 shows the heat transfer between above critical pressure steam, and three different streams. The three heat exchangers each have their own individual drain cooling zones. Each heater is designed for its own heat transfer reversibility criteria. A hot well 1, with a condensate pump 202, a suction line 2 are shown. A tank 401 is hot well for the drains stream 4, wherein a heater drain pump 205 has a suction line 5. Streams 6, and 3, combined into a stream 7 is heated in a reversible manner, in a heat exchanger 117. A final feedstream 81, enters a heat exchanger 108. Cycle is shown by node points 8, 10, 11, 12, 13, and 14, with steam turbines 109, 111, and 113. Notice heaters 116, 117, 118 at different levels. The three heaters, as pointed out before, are INDIVIDUALLY designed for reversible heat transfer. In addition, the streams being heated can be either on the shell or the tube side, as dictated by other considerations. The COMMON level 90 is maintained to allow for a singular level control system, with an equalizing line 19. The point being EMPHASIZED is that a single stream of the THERMAL ENERGY PROVIDER, stream 18, is used to heat a

MULTITUDE of streams 51/7/52, with heat transfer reversibility criteria intact .

Fig 2J is similar to Fig 21 except that the heat exchangers 116, and 117 do not have their own individual drain cooling zones. The entire drain cooling is performed in heat exchanger 118. Streams 120, and 122 are to subcool the saturated drains 20, 22 to avoid flashing. The reminder of the discussion applies from Fig 21. Heat transfer in heat exchanger 118 is reversible.

Fig 2K shows the use of U-tube configuration in the design of a heat exchanger for reversible heat transfer. The U-tube design may be necessary to address the expansion problem in the design of very high pressure, and temperature heat exchanger. A stream 10 enters a turbine 110 with exhaust stream 12 at above critical pressure. A stream 11 is used for reversible heating of a stream 7. Hot well 1, a pump 202, and streams 3, 4, 5, 6 are per the previous discussion. Stream 7, a heat exchanger 107, and a stream 8 follow rest of the heating to exit as stream 9. Stream 11, on the shell side of heat exchanger 111, exits as stream 13. The purpose of a heat exchanger 107 is to provide ADDITIONAL surface, IF needed, than what is available in the U-tube part only. The heat exchanger 107 can be located in location 108 as an alternate, to result in a simpler level control system. The key is to have the flexibility of UNEQUAL heat transfer surfaces for the condensing, and drain cooling zones, in order to IMPOSE heat transfer reversibility.

Fig 3A is a Mollier diagram plot 1, 2, ....11, for reversible, regenerative heating water cycle. HEAT TRANSFER REVERSIBILITY is imposed in the feedwater regenerative heating. A bleed stream at point 2, at above critical pressure is the key. Additional bleed stream points 3, 5, and points 7, 8, 9, 10 are to meet other cycle needs, if required.

Fig 3B is component diagram for Fig 3A, and shows single stage feedstream heating, in a reversible manner. A stream 1, 16 at a pressure substantially higher than the critical pressure, is expanded through a turbine 101, with stream 2 at above critical back pressure. Heat transfer in heat exchanger 121 follows HEAT TRANSFER REVERSIBILITY between streams 221, and

229. The reminder of the (excess) steam follows node points 22,

3, ...6, 11 to complete the cycle. Thermal energy is added at

23, 24, 25. A condenser 111, and pumps 28, 29, and a heater drains pump 30 are shown.

Fig 3C shows an expansion line when ANHYDROUS ammonia is used as working fluid. An attempt is made to "fit in" a practical expansion line, with single reheat. A pressure of 200 psia or so, with saturation temperature of about 100 Deg. F, is the LOWEST back pressure for the cycle. This will allow the use nature's heat sink of about 60 deg. F, for waste heat rejection. The final turbine exhaust has a large amount of superheat thermal energy, 6/9. Unlike a water cycle, in which an expansion line can be "fitted in," that will allow an expansion down to 1 psiA, and at the same time hit the 1 psiA line very close to the saturation line, no other working fluid works so nicely. A bleed stream point 2, is at above critical pressure. The diagram is self explanatory based upon previous discussion for a water cycle. Portion 401 (20), 402, 22 of the expansion line pertains to Fig 3H, and will be discussed later.

Fig 3D is similar to Fig 3B, except, that working fluid is ammonia, and the heat source for the cycle, streams 111, and 112, is steam at above critical pressure, thus allowing for heat transfer reversibility. Node numbers are per Fig 3C. A significant departure from the water cycle pertains to TWO reversible heating stages of stream 11. A stream 20, at a pressure substantially higher than the critical pressure, is used in a heat exchanger 107. Temperature at 7 is still relatively low, so as to design a SECOND reversible heating stage, in a heat exchanger 107. This is in addition to a reversible heat exchanger 106, with stream 2 at above critical pressure as well. The streams 111/112, are also at above critical pressure, from a water cycle, using single stage reversible feedstream, heatin . This arrangement will be used to form a composite, multi working fluid power cycle.

Fig 3E, applies to carbon dioxide as working fluid, employing reversible regenerative feedstream heating. The lowest back pressure for this cycle, node 2, will be as high as 1075 psi, the critical pressure, with corresponding saturation temperature of 88 deg. F. The condenser cooling 2/3 may have to be supplemented with a refrigeration cycle. However, we do have the porogatlve of pumping "almost liquid" carbon dioxide which will entail higher pumping power. Notice turbine 1/2, a pump at

3, and superheat thermal energy at node 2.

Fig 3F shows the devices for the carbon dioxide cycle, using reversible feedstream heating concept. Coll 52 is the refrigeration coil, downstream of the REVERSIBLE cooling via modulated feedwater stream 96, and condensate stream 97 from the "parent" steam (water) cycle. Streams 196, 197, 198 are superheated. Stream 198, after being cooled in a reversible manner by the water streams 96, and 97, is cooled further, to about 40 to 50 deg. F by a refrigeration system, a stream 52.

Pressure at 1 is extremely high, and an innovative ejector arrangement, to be discussed later, is used. A hot well 199 shows collection of subcooled condensate, from a water cycle, as a heat sink for carbon dioxide cycle. This is accomplished by bypassing the condensate stream 104 around scavenging steam through use of trays 103, below circulating water tubes 202. An equalizing line 105 is shown. A tank 106 collects subcooled condensate. A stream 97 is delivered as heat sink for the carbon dioxide cycle. A pump 109 has suction stream 107. The remaining, saturated condensate system has a hot well 199, and is for use in the water cycle. Entire condensate stream may not be required as heat sink for the carbon dioxide cycle. A suction line 201, a pump 111, steam exhaust stream 200, and a discharge stream 102 are shown. The refrigeration cycle is based upon a pull-through cycle concept. A driver 350 is the power source for the train having a blower 250, a turbine 251, and a compressor 252. The streams 50/51 are at essentially atmospheric pressure. The expansion of stream 51 through the turbine 251 results in a colder stream 52, which is the heat sink for the carbon dioxide cycle. A heated stream 53 is recompressed, and discharged as stream 54. The system

50, .51, ...53 can thus be used as a refrigeration AS WELL AS a heat pump system, in which case heat exchanger 152 represents

"free" thermal energy, and yields stream 54 at a higher temperature than stream 50. As a variation, blower 250 can be a compressor, with stream 51 cooled by an external heat sink. The expansion thus through turbine 251 will be colder as well. The compressor 252 is thus deleted, and a pressurized refrigeration cycle is shown.

Fig 3G shows reversible feedstream heating, double reheat ammonia cycle to be reviewed in conjunction with Fig 3D. The heat source for this cycle, streams 50, 51, 52 is however subcritical steam. This arrangement is for low temperature combined cycle application. The heat exchange from the topping water cycle to a bottoming ammonia cycle will NOT be reversible. The main feature is the 1650 psi ammonia bleed stream 11. All the water drains (not shown) are introduced into the appropriate feedwater heaters of the "parent" cycle, to allow for a singular heater drain level control system, for each regenerative heating stage. An ammonia condenser 61, at about 200 psi, a pump 207, and a line 7 are shown. Feedstream 9 is heated in a heat exchanger 11, in a reversible manner. Stream 10 is further heated in a regenerative, and not reversible manner by steam lines 50, 51, 52 for primary heating, as well as reheat, between nodes 2/3, and 4/5.

Fig 3H shows REVERSIBLE, MULTI STAGE, feedstream heating concept. The ammonia cycle is shown by node points 50, 51, ...54. An above critical pressure stream 401 is introduced, IN ADDITION to, the other above critical pressure stream 22. The stream 67 from the water cycle is also at above critical pressure. The ammonia cycle thus has THREE reversible, heating stages in heat exchangers 152, 153, and 154. Similarly, the water part of the composite cycle ALSO has THREE reversible heating stages in corresponding heat exchangers 252, 253, and 254. An external heat source 165 "drives" the entire cycle. The teachings being stressed are, that the reversible heating concept, using extraction streams at above critical pressure, can involve MULTI stage heating of the feedstream(s ), in a MULTI fluid composite cycle.

Major hardware, as building blocks, to SUPPORT a cycle around very high temperature, and pressure boundary design conditions, based upon above mentioned teachings, is described below:

Fig 4A shows a stream 1 at very high temperature, and pressure as the motivating fluid for a proposed innovative ejector 8. An expander 302 for these design conditions at 1, is not yet available. The proposed design can also be used for very high pressure combined cycle, with low throttle flow. As can be seen, the flow through the expander 302 increases considerably due to recirculat ion of stream 3, which will off set, to a large degree, the efficiency penalty associated with small turbine blade height. A partially expanded stream 3, as induced fluid, is introduced via several parallel paths 5, 6, and 7. Stream 2 is used as working fluid. Stream 4 continues through the remainder of the cycle. The proposed ejector system is expected to be upto 85 % as efficient as a system with the design conditions of node 1, delivered into an expander 302, if one was available. The boiler 99, at higher pressure, and the turbine 302 can "float," and do not have to be matched.

Fig 4B shows that innovative ejectors do perform a useful purpose for a particular objective. If the available technology cannot provide a turbine for process 1/2, it should not limit the cycle to start at point 3. A turbine at 3 can provide a stream 5, which can then be "mixed" with the stream 1 to yield a stream 6, as determined through mass, and energy balance. However, condition point 6 cannot be obtained in any practical application. An innovative ejector will, however, deliver a continuous stream 7, which is in a straight line from point 6. An easy comparison can be made of the two flow paths, one with the turbine only, and the other with a topping innovative ejector. An innovative ejector at 1 is more efficient than only a turbine at design condition 3. This will, however, be not as efficient as a turbine along process line 1/2, IF one was available. Path A along 1/2/3/4 is the very high pressure turbine path. Path B is with innovative ejector to "mix" streams 5, and 1 to obtain stream 7. In path A, work done is enthalpy 1/2/3/4 times Wl; and heat added is enthalpy 2/3 times Wl . In path B, work done is enthalpy 3/4 times W1+W2, and heat added is enthalpy 7/3 times W1+W2; where Wl is the throttle flow at stream 1, and W2 is the induced flow at stream 5, as recirculated by the proposed ejector.

Fig 4C shows the principle of ejectors. An ejector is simply a "mixing" device for two or MORE fluid streams, at different initial pressures. These fluid streams, for sake of simplicity, are assumed to have no chemical reaction, i.e. "mixing" is only physical. The three fluid streams A, B, C are expanded in nozzles to a common "mixing" pressure PM. The high velocity fluid streams exchange kinetic energy by following the law of conservation of momentum. The "mixed" stream is now at a condition point 7. Process 7/8 is stagnation, by which, kinetic energy at 7 is reconverted as pressure at point 8 for the

"mixed" stream, following the laws of conservation of energy, and conservation of momentum. It should be pointed out that when two fluid streams at different velocities are combined, due to "collision," a portion of the kinetic energy is converted to thermal energy. This is the non reversible part of an ejector design. To minimize this effect, various fluid streams, at high velocities are combined in "squirts."

Fig 4D is another illustration of the theory behind ejectors. The key to their design is the laws of conservation of energy, conservation of momentum, and conservation of mass. Kinetic energy K7 can be converted to pressure/enthalpy through stagnation in a dlffuser at 7. The fluid A at 1 has initial enthalpy HI. A nozzle converts this total energy into components H2 for enthalpy, and K2 for velocity, or the kinetic energy equivalent. The similar values for fluid B, and C are shown. After "mixing," the energy values are H7, and K7. The stagnated, "mixed" stream 8 is thus obtained for suitable use.

Fig 4E shows the Innovative ejector arrangement with controls to achieve certain intended design conditions, such as the pressure for the "mixed" fluid streams, or certain plant alignment. In the design shown, motivating, as well as the induced fluid is controlled, by way of "mixing" ratios, in steps. This is done through non pressure drop (gate) type of ON/OFF valves. The valves are controlled through a signal processor to produce intended results, such as keeping the main steam throttle valves fully open for part load operation, or to deliver a predetermined pressure, such as above critical pressure, for single stage feedstream heating cycle concept. It should be pointed out that we may require "final trimming" by a throttle valve, for part load operation, as the innovative ejectors will deliver only a step performance. The gate valves are proposed, to minimize the pressure drop. The motivating fluid is delivered in several parallel paths by ON/OFF gate valves. The "slowing down effect" is applied to the motivating fluid, by introducing the "slow moving" induced fluid, in steps. Thus, a passive, single point operation innovative ejector, is transformed into a useful "active" device.

A motivating stream 1 is conducted into several parallel paths that can be opened, one at a time, by gate valves 2 through 5. Each of these parallel paths 28 to 31 has an ejector such as 128. An Induced stream 7 is similarly conducted into several parallel paths 8 to 11. Path 11 is further divided into several parallel paths 12 to 15. These in turn are controlled by ON/OFF gate valves 16 to 19. Each of these streams 20 to 23 are then conducted into nozzles 24 to 27. Thus stream 28 can be "mixed" with anywhere from one to, in this case four, induced fluid streams. The parallel paths 28 to 31 emerge as paths 32 to 35, which are combined into a header 36 for the "mixed" stream. A controller 37 is the "brain" to produce the intended "mixing." It receives the signals to deliver the "mixed" stream 36. For example, if the intended objective is to have the main steam throttling valve fully open, to minimize the pressure drop, a position indicator 38 can direct the controller 37 accordingly. Similarly, if the objective is to have a predetermined pressure at 39 (36), a pressure transmitter 40 will provide the required signal to the controller 37. The objective is to have the ability to "mix" the two fluid streams in a large number of variations in the flow ratios, to achieve the intended cycle design. Additionally, both the fluid streams, the induced fluid, as well as the motivating fluid, are imparted PRE "mixing" velocity to minimize the "mixing" loss .

A path as streams 50, 51, and an ON/OFF gate valve 150, receiving signal from the controller 37, are shown. This supplemental path alignment is used when the variable resistance, as provided by the Innovative ejector has to be ZERO, for a particular design function. The induced fluid stream is completely shut off, however paths 28/32, ...31/35 will still have some resistance. The supplemental path 50/51 is, thus, to off set this effect.

Fig 4F shows the design for a very high pressure, and temperature ejector, through a passive thermal shield arrangement. This is done by inducement of a cooler stream, which will exert only a very small differential pressure on the inner shield wall 98. The main ejector has motivating stream 14/15. The induced fluid 1 follows the main path as 1, 2, ..7. The cooling stream 8/9 is diverted via a diverter ejector 13, per Fig 4G. The stream 8/9 flows between walls 98/99, and provides a thermal shield between the very high temperature, and pressure motivating fluid 14/15, and the pressure boundary wall 995. The inner shell 98 follows the same profile as pressure boundary surface 995. The cooing stream 8/9 thus isolates the very hot motivating fluid 14 from the pressure boundary 995. The component 98, has to be designed only for the differential pressure between stream 14/15, and 8/9. The cooling stream 97 can be further cooled via a heat exchanger

108, or through direct injection of a cooler stream 50, or some combination thereof.

Fig 4G shows an arrangement when a fluid flow is to be diverted. The device thus described will be called a diverter ejector. An orifice is used as well. However, an orifice will involve higher pressure drop. A main stream 1 is split into streams 2, and 3. The stream 2 is induced via an ejector 103, and recombines with stream 3, at 4. Notation 5 shows the pressure differential "created" by the ejector 103. The diverted stream 2 can be passed through a device 6, such as a HEAT EXCHANGER or any other component. A valve 7, is to further modulate the flow in stream 2. The flow eventually follows path 8 to the remainder of the cycle.

Fig 4H shows an extension of the "smart" innovative ejector of Fig 4E. In this case a series of induced fluid streams 71, 72, 73, 74, and motivating fluid streams 11, 12, 13, 14 are shown. Several parallel flow paths of the motivating as well as induced fluid streams of Fig 4E is preserved. However, additional sources for the induced as well as the motivating fluid streams, by switching to different parts of the cycle, using controller (s ) (not shown), is introduced. Thus, by analyzing the cycle for different loads, a "smart" ejector system, as based upon teachings of Fig 4E, is shown.

Fig 5A demonstrates the incorporation of the best design features of a very large, as well as very small size shell and tube type of heat exchanger. A large diameter shell 1, a number of small cross section tube sheets 10, with a header 7 is shown. A path 8, an increaser 9 is shown that delivers fluid to various tubes 11 via a THINNER tube sheet 10. Similarly, other tube sheets are at 2, 3, ....6. The various shell-less heat exchangers, such as 9/10, are thus combined into one common shell 1, via a tube sheet 12. Tube sheet 12 is subjected to relatively lower shell pressure. The shape of the proposed smaller cross section tube sheets 10 does not have to be circles. Any suitable shape, as an option, can be "crowded" into the overall large circle, the main shell 1 as shown. The channel head is thus deleted. Variations, such as, a large, reinforced tube sheet (ribbed construction) for component 12, with individual feeds is a variation based upon teachings.

Fig 5B is an extension of the innovation of Fig 5A. The tube to header transition, for boiler pressure parts is effected via an intermediate tube sheet. In doing so, numerous individual tube to header connections are replaced with easily constructable, tube to tube sheet connections, resulting in smaller diameters tubes. However, their structural strength will have to be addressed by redesigning the supports for the tube banks, against the flue gas flow. A large header 1, i.e. boiler pressure part, delivers a stream 2 to the smaller diameter tubes via a tube sheet 3. The pressure parts upto a suitable point 6 are shielded from the hostile flue gases.

Fig 5C is an arrangement that will permit the use of standardized heat exchange, or any other type of components; which can then be "headered" together to design an overall system. Additionally, the proposed design layout will permit smaller, easy to design components rather than more harder to design larger components. A shell and tube type of heat exchanger design will, for example have thinner shell thickness, and thinner tube sheet. This design will deliver a more reliable system. Additionally, only the failed smaller components can be replaced, rather than replacing a very large component. A stream 1 enters the four heat exchangers 90, 91, 92, and 93, via lines 2, ...4. The exiting streams 6...9 on the tube side are recombined into a common header 11. Similarly the shell side stream 11 is divided into four streams 12...15. The exiting fluid streams are recombined via lines 16...19 into a header 20. We can increase or decrease the number of parallel paths to suit. We should thus be able to manufacture the heater shells from seamless pipes as opposed to rolling very thick plate material .

Fig 5D is a design to reduce tube stresses, caused by the bends, as in a U-tube type of construction of a heat exchanger. Also, for straight tube construction, stresses due to anchoring at the tube sheets is deleted. Fluid A, stream 1 enters a free standing inner tube 13. The stream 1 travels upward, and enters the annulus space, between the outer tube 14, and inner tube 13. The inner tube has holes at the top. The stream 2 exits as shown. The other fluid stream B exchanges heat along its travel

3/4. It is to be pointed out that the arrangement can also be used for a "shell-less" arrangement as well, as in the boiler pressure parts design, for heat transfer. The pressure parts

10/12 can be curved, such as shown by 20/21. Tube sheet 11, and tube 13 are subjected to relatively small pressure. In addition, teachings of Fig 5A can be applied, as shown by headers 50/51, and 60/61. In this case inlet, and outlet connections, for fluids A, and B can be combined, and fed by headers. The inlet, and outlet connections are staggered, to suit. The free standing approach can be extended to include ceramic tubes as well. In this case, a metal flange 76 has an extension part 77, with "roughed" or "notched" inner, and outer surface. Outer ceramic tube 114, "thicker" along the length that covers "lip" 77, is "built" over it; thus resulting in a ceramic to metal transition. The flange, or a threaded nipple, as an alternate, is connected with the tube sheet 12 through conventional means. As an alternate, the ceramic to metal transition is forgone, and the outer tube 114 can be "formed" as a flanged tube, which is then sandwiched between tube sheets

12, and 112, and secured through conventional means.

Fig 5E shows the end connection for the top portion of the free standing heat exchanger idea of Fig 5D. The top support 7 is via a cap 1, welded to the outer, pressure part, tube 11. The internal tube 12 with holes 3, directed downwards, has small recess at 5, and 6 for thermal expansion, and positioning. The material for part 12 can be different than that for the pressure parts 1, and 11. Additional rings (not shown), with holes, are used for added support for very long, free standing, tube application.

When coal is burnt, using prewarmed air, say at 500 deg. F, the products of combustion are produced at almost 3800 deg. F. These gases are quite hostile. Thus the objective will be to utilize this heat source, in a topping cycle. The heat rejected from this topping cycle, a clean source, is then used for subsequent bottoming cycles. This will yield multi fluid combined cycle.

Fig 6A shows three major portions of a boiler. The highest temperature portion of the boiler, the radiant section, heats steam at near atmospheric pressure. Thus hostile gases in the boiler, at very high temperature, are used for heating working fluid stream 1, at near atmospheric pressure, and nearly saturated. The stream 1 enters the back pass of a boiler 99 in a heat transfer surface 2. A stream 3 travels via ducts or large pipe, to the radiant section of the boiler, into a heat transfer surface 4. A stream 5 is conducted to a steam turbine

8. The back pass of the boiler, also beats cold reheat stream

7, at conventional pressure of about 500 psi, from say 500 deg.

F to 1000 deg. F. The convection pass of the boiler heats stream 9, at say 150 psi, from 600 deg. F to very high temperature of say 1700 deg. F. The subatmospheric pressure steam, exhaust stream 6, from the steam turbine 8 provides a heat transport loop for the remainder of the cycle, which will be discussed later.

Fig 6B shows the boiler "driving" an air topping cycle, at near atmospheric pressure. HEAT TRANSFER REVERSIBILITY is

Imposed on the tail end of the boiler. Streams 5, and 61 are combined into stream 7 by matching the temperature at 13, to ensure heat transfer reversibility in the "mixing" process.

This teaching will be applied in several subsequent identical situations. There will be a mass flow disparity between the flue gas, and working fluid stream, air in this case. Both air, and flue gas have approximately equal specific heat; 0.25

BTU/Lb./Deg. F. However, flue gases are to be cooled from about

3500 deg. F at the burner, to about 275 deg. F, leaving the boiler. Air stream is heated from, in most part, from about 200 deg. F to about 2200 deg. F. Thus, in order to match the energy exchange, mass flow of the two fluid streams, will have to be adjusted accordingly. Therefore the air flow is approximately

161.25 96 of the flue gas flow, { (3500-275)/(2200- 200)}. The boiler 200 is used as a large air heater for providing working fluid for a pull-through cycle. A forced draft fan 201 delivers air, which is preheated in a heat exchanger 102 to about 200

Deg. F. The air stream 3 is now divided into streams 4, and 6.

The stream 4 is further heated, by bleed stream in a heat exchangers 104, to say 600 deg. F. The stream 6 cools the flue gases in the back pass of the boiler in a REVERSIBLE manner.

The stream 5 is introduced into stream 61, at point 13, matching temperatures as discussed before. Section 98 bf the heat transfer surface is of metallic construction for heating the air stream 7 to about 1300 deg. F. Section 99 can use other barriers such as ceramics, refractory or even metal. The air at atmospheric pressure as working fluid, heated to over 2000 deg.

F exits the radiant section of the boiler as stream 8.

Fig 7A shows an Innovative arrangement to deliver pressurized fluid for various cycle applications. The pressurized fluid, can be liquids or gases. The pressure is created using double acting arrangement. The cylinder can be very long, with piston "driven" by linear motors 215, and 216. The linear motors 215/216 can be totally enclosed inside the cylinder 17, as the electric energy can be transmitted "through walls" as well. This will eliminate the design of seals for the rods 15/55. The system is designed to ensure that the piston rod will always be in tension. A reservoir 1 is for low pressure, and 50 for high pressure fluid streams. As the piston 16 moves towards right, low pressure fluid is drawn via path 1/2/3/4. At the same tine, high pressure fluid is delivered via path 7/11/13/14. Conversely, when the piston 16 moves towards left, the low pressure fluid is drawn via path 1/5/6/7, and at the same time, high pressure fluid is delivered via path 4/12/14 for continuous operation. Pressure is exerted by nitrogen or suitable gas in cylinders 51/52. A large number of parallel cylinders, such as 17, driven by a single linear motor can be designed.

Fig 7B shows the "electric drives," 215/216 of the arrangement of Fig 7A, substituted by "mechanical drives." The linear motion is provided by a much larger diameter piston arrangement 205, driven by a relatively low pressure system of pump 201. The force, on the piston rod 55, which is still designed to be in tension, is thus amplified. For example, if the diameter of piston 205 is four times that of piston 17, the design pressure necessary for pump 201 will be approximately one sixteenth of the pressure required to be delivered into reservoir 50. Thus, a very high pressure cycle can be designed. A tank 101, at atmospheric pressure, delivers liquid to a pump 201. By sequentially opening valves 104, and 106, the piston 105 can be moved in direction 70, pulling on piston rod 55, a discharge stroke for piston 16. Another piston arrangement, not shown, similar to piston 205, provides the stroke towards direction 71, maintaining tension only, on piston rod 15. A controller 40, via lines 40, 41, ... 46, controls valves 104/106, and 108/161 to provide the required motion. A position indicator 143 provides switching from one drive piston 205 to the other (not shown), by processing the information by the controller 40. A hydraulic shock absorber 72 is to address the pressure surge due to sudden opening, and closing of the various control valves. In both Fig 7A, and 7B, the "pull" on the piston rod(s) is assisted by "some push" as well, if thus designed .

Fig 7C shows an arrangement for pressurized enclosure to be able to use the existing equipment for much higher design pressure application. For example, an existing gas turbine for say 200 psi, and over 1500 Deg. F, is used for a cycle for steam as working fluid, for say 2000 psi, and same temperature, with relatively minor design changes. This is accomplished by maintaining an external pressure on the said equipment. An enclosure 50 is shown to contain the equipment 53 with inlet/outlet lines 5/6. A pressure source 51 is communicated via lines 3/4, and regulated by a control valve 103. A purge line 20/21, and a control valve 120 will maintain the desired pressure inside the enclosure 50. A controller 54 thus receives the pressure signals 10/11/12 to "orchestrate" the control valves 103, and 120, via lines 13/14, during the system operation as well as start up. The system is programmed to provide the necessary external pressure on the pressure parts of equipment 53. The pressurized enclosure concept can be extended to enclosing Just the seals 55 or other parts of any equipment. The concept is to replace the atmospheric pressure with "created pressure" for a particular equipment, for use for higher design pressure. The technology development thus shifts to a much lesser challenging system as shown. A stream 70 is for make up purpose. The above pressurized enclosure approach can be applied to the concepts of Figs 7A, and 7B, by applying teachings .

Fig 7D shows the arrangement for extremely high pressure, and temperature turbine design. Here, a valve-less turbine is shown, which is simply a "spinner" 3 in a shell 31. The RPM (revolutions per minute) is controlled by varying the field strength 7 of the electric generator, as controlled by a controller 9, designed to receive a signal from the RPM pick-up device 8. This varying stator field strength is essentially a "breaking" mechanism on the turbine. This results in a corresponding output through a stator 6. The electric generator thus follows the turbine load, which delivers a certain torque. However, a run off is prevented, and a constant RPM system, for electric generation is devised. High pressure working fluid stream 1 is delivered to the "spinner" 3 via several smaller lines 1, into a header 2. The working fluid stream follows the path shown by 21, 22, ..25, with stream 5 pressure to be above critical .

Fig 8A represents a pressurized recuperator, heat exchange 2/3 vs 5/6, resulting in exhaust 7 cooler than exhaust 8, if the expansion was to have been in one turbine 4/8, as in the present technology. Instead, an innovative arrangement of POST RECUPERATOR EXPANSION is shown via an added turbine 6/7, and truncating turbine 4/8 at point 5, i.e. a "shorter" turbine 4/5 is used. This arrangement allows a larger quantity of heat energy to be recuperated, since temperature at 5 is higher than temperature at 8, the current technology. It is recognized that work 6/7 is less than work 5/8. However, there will be an overall efficiency gain due to decrease in fuel needed.

Fig 8B is a device diagram for the gas turbine system of Fig 8A. The cycle shows a pressurized recuperator 102, and yields a COOLER exhaust at 7 as discussed before. Various design values are shown to aid in understanding, and are not meant to present an actual design. Ambient air 1 is drawn into a compressor 101. A stream 2 is heated in a pressurized recuperator 102. A heated stream 3 enters a combustor 103. A working fluid stream 4 at about 2200 Deg. F expands through a truncated gas turbine 104, with exhaust stream 5 at say 60 psi. Stream 5 imparts high grade thermal energy to stream 2. A cooler stream 6 continues its expansion to stream 7, at atmospheric pressure, in a gas turbine 106.

Fig 8C shows a recuperator, heat exchange 2/3 vs 9/10, and post recuperator expansion 10/11, into subatmospheric pressure regime. This allows a cooler exhaust, 11 vs 20; and larger quantity of heat being recuperated, 9 is "hotter" than 20. However, there is a small penalty in the work done, 9/20 vs 10/11. Lesser heat is rejected along 11/12. Compression 1/2, and expansion 4 through 11 are decoupled. The corresponding compression is accomplished in two steps, 1/2, and 12/13. This approach makes the system technically less challenging. The recuperator 9/10 is in the subatmospheric pressure part of the cycle. However, 9/10 can be in any part of the expansion range. The key is to have POST recuperator expansion. The recuperator can thus be an INTERMEDIATE recuperator, and not NECESSARILY at the TAIL end.

Fig 8D is device diagram, and uses the approach of "wandering around, " on the enthalpy/entropy diagram, as discussed in Fig 8C. Heat is added at a number of suitable pressure points, with fuel streams 60, ..63. The cycle has very large expansion ratio, afforded by the use of a subatmospheric pressure cycle, at the tail end. Heat recovery 11/12, 13/14, via heat exchangers 111, 114, is to drive a bottoming steam, and/or ammonia cycle. The working fluid stream 1, 2, 3,

14 is reheated. Pressure at 11 is subatmospheric.

Fig 8E shows a post recuperator expansion gas turbine cycle with reheat i.e. after partial expansion, additional fuel is added to the cycle. Ambient air 1 is compressed in a compressor 301. Stream 2 is preheated in a pressurized recuperator 102 using partially expanded stream 7. Fuel is added in a combustor 203, and stream 4 is expanded in a gas turbine 304. Stream 5 is reheated in a combustor 205. Stream 6 is expanded in a gas turbine 306. The partially expanded stream 7, is used in a pressurized recuperator 102 to preheat the compressed air stream 2. The relatively cooler stream 8 is finally expanded in yet another gas turbine 308 to complete the expansion to a stream 9, at atmospheric pressure.

Fig 8F, based upon teachings, shows an innovative ejector that will enable the use of very high temperature, and pressure design conditions at point 42. All the fuel is added in a combustor 104, instead of a reheat type of cycle in Fig 8E. The innovative ejectors, because of their simplicity in design, allows the use of extreme design conditions. A post recuperator expansion gas turbine 307, with an ejector 142, using very high temperature stream 42 as motivating fluid, and streams 6, 51, 52 or 53, or some combination, as induced fluid is shown. Ambient air 1, with precooler, and intercooler, as shown, delivers a compressed air stream 3. Stream 3 is preheated in a pressurized recuperator 103 using partially expanded stream 6. Fuel is added in a combustor 104, yielding products of combustion stream 42 at very high temperature, and pressure. An innovative ejector 142 is introduced between the stream 42, and a gas turbine 305. The induced fluid for this ejector can be one or more streams, such as partially compressed air stream 52, partially expanded products of combustion such as stream 51 or 6. The stream 5 is expanded in a gas turbine 305. The stream 6, at a pressure above atmospheric pressure, is used in a pressurized recuperator 103 to preheat the compressed air stream 3. The relatively cooler stream 7 is finally expanded in yet another gas turbine 307 to complete the expansion to stream 8 at atmospheric pressure. Because of the ability to use very high temperature motivating fluid in the innovative ejector 142, stream 4 is further heated in heat exchanger 160 using indirect heat transfer from stream 60, thereby yielding even higher temperature at 42. In a similar manner, stream 50 is diverted along path 70/71/72 to preheat this induced fluid stream in a heat exchanger 170, and external heat source 73 in yet another heat exchanger 171. Additional streams 81, 82 as motivating fluid streams are also shown, as an option to optimize. The entire discussion can be applied to a pull- through cycle configuration, based upon teachings, i.e. using an innovative ejector in place of several combustors, as discussed before.

Fig 8G uses more than one INTERMEDIATE recuperators, 5/6, and 7/8 as shown. To optimize design, use of HIGHER grade thermal energy 5/6 as well as relatively LOWER grade thermal energy 7/8 is shown. The objective is to have a multitude of post recuperator turbines, TWO in this case, 6/7, and 8/9, resulting in a still cooler exhaust at 9. A heat exchanger 9/10 represents the "waste" heat. The design shown pertains to subatmospheric pressure application. The teachings can be used for above atmospheric pressure application as well.

Fig 8H shows various components pertaining to the expansion line of Fig 8G. A heat exchanger 105' is a pressurized recuperator for preheating compressed air stream 2. As an alternate, thermal energy 5/6 can "drive" a high temperature cycle, such as a cycle with water as working fluid, with reversible heat transfer, via a heat exchanger 105. The heat exchanger 107 can "drive" a relatively lower temperature cycle, such as a cycle with ammonia as working fluid, in a reversible manner as well. The heat exchanger 109 pertains to the "waste" heat sink, since the cycle is a pull-through cycle. The teachings can very well be applied to a conventional, pressurized Brayton cycle. The key is the use of MULTIPLE INTERMEDIATE recuperators, 105, and 107, i.e. recuperators with POST recuperator expansion, as in turbines 303, and 304 respect ively.

Fig 9A shows a power cycle for the transport sector. An pull-through cycle, using the exhaust from a piston engine 98, downstream of the catalytic converter 101, if applicable, with optional supplementary firing 203 is shown. The catalytic converter reburns carbon monoxide, to yield higher temperature of working fluid stream 2 for the pull-through cycle. The power produced is transferred to the engine via a flywheel 9. A heat exchanger 105 with protection against formation of acid is shown; since stream 5 will be cooled to below dew point. The stream 2 will produce EXTRA work in a pull-through cycle as is. However, supplementary firing in a combustor 203 will yield power boost as and when needed. A temperature controller 52 in stream 4 will over-ride a pedal 50, input for fuel. This is to protect turbine 304. Stream 6 is recompressed in a compressor 306 for final exhaust at 7. During normal operation, pedal 50 "drives" the piston engine only, via linkage 60, with pull- through cycle in operation as well. However, supplementary firing in combustor 203 is not operated. When the pedal 50 is summoned for a boost of power, extra fuel is added to the power train, via linkage 51. Thus piston engine can be sized for normal operation, with power boost capability. The pull-through cycle, without the supplementary firing is, however, working continuously to reduce the piston engine size.

Fig 9B shows large portion of the negative compressor work, being shifted to the electric grid, or other less expensive sources of mechanical power, for transport sector. This is achieved via having stored compressed air 993 on board, in a vehicle. The compressed air stream 4, is heated in heat exchanger 102, with exhaust stream 2 of a piston engine 98, downstream of the catalytic converter 101. The working fluid stream 5, as the motivating fluid, and stream 20 as the induced fluid, are used in an innovative ejector 320. This is significant, because, as the pressure in the vessel 993, deteriorates, a constant pressure inlet into gas turbine 305 can be thus maintained. The innovative ejector will vary the induced fluid 20 to achieve this, a feature that was discussed before. The exhaust is show by stream 6, and the power is transmitted to the power train via gear 7, attached to the flywheel. The additional mechanical power is produced, wherein the compression stroke is "driven" by the electric grid, and the heat source for the add-on cycle is WASTE HEAT of the main piston engine. Even though the add-on cycle produces extra power from waste heat stream, the stored compressed air may have to be used on an intermittent basis for power boost only.

The mechanism 50, 51, 60 as discussed in Fig 9A can thus be used. Supplementary firing in stream 5, based upon teachings can be added to optimize the design.

Fig 9C, shows an onboard compressed air source for an innovative, pull-through cycle configuration. A turbine 311 produces work, using unheated stream 1 while providing a heat sink, as in stream 2, for the pull-through cycle. This stream is heated in a heat exchanger 106 using the waste heat of stream 6. Fuel 4 is added in a combustor 203, and an innovative ejector 320 with induced fluid 20 is shown. This will ensure a constant pressure at working fluid stream 5 as discussed in Fig 9B. The exhaust stream 6 is cooled in heat exchanger 106. The cooled stream 7 is recompressed in a compressor 307. A heat exchanger 107, provides a waste heat sink. The final exhaust 8, and power 9 are also per the previous discussion. The piston engine exhaust stream 11/12/13 with catalytic converter 101 provides the preheating of stream 3 in a heat exchanger 102. In order to conserve the compressed air 1, and use it only on an intermittent basis, linkage 50/51/60 as per Fig 9A is used.

Fig 9D shows a composite cycle, using various teachings discussed before, as applied for the transport sector, with on board compressed air in a vessel 993. A gas turbine 301 provides a cooling stream 2. The power train is shown by components 301, 401, 402, 302, ....306, 98, and 97. An electric generator is shown by 401, which drives the wheels 52/53 with motors 50/51, using electric energy via lines 40/41/42/43. As an option, the power can be transmitted mechanically via gears 402, reducing gear 30, and a flywheel 31. The entire cycle is shown by node points 1, 2 17. As per teachings, the innovative ejector 100, recuperators 111/113, with waste heat sink 114 are shown. A relatively cooler air stream 4 is used for combustion of fuel 105 in a combustor 104, without much excess air. The reason for this approach is to be able to use highly volatile fuels, which will require relatively lower temperature of combustion air. Streams 5, and 17 are combined via a mixer 106. A stream 6, still at very high temperature, is the motivating fluid with a stream 8 as the induced fluid in an innovative ejector 108. This provides a relatively constant temperature, and pressure working fluid stream 7, for a gas turbine 302, based upon teachings. The power train has a fly wheel 98 to provide uniform mechanical energy. A clutch 97 will activate a compressor 306 during breaking, coast down etc., to recharge the vessel 99. The "driving" controls 50, 51, 60 from

Fig 9A are used based upon teachings.

Fig 10A shows an innovative expansion line for use in a once through heat transfer arrangement, for a combined cycle application, and for other cycles as well, based upon teachings, thus developed. In expansion line 1/2/51/4, pressure 4/8/11 is intended to be the back pressure. However, point 4 results in high moisture content on the Mollier Diagram, not suitable for use in a turbine 3/4. In order to overcome this, the expansion line is terminated at point 3, with relatively lower moisture content. Moisture separation 3/5, and reheat 5/9 is shown. The expansion line can then follow 9/7/8. Thus, a large number of expansion line combinations can be formulated, using single or multitude of moisture separation, and reheat combinations. However, reversible reheat 5/9, and/or 7/10 is accomplished by using thermal energy of stream 2, which is at above critical pressure. In addition, points 5, and/or 7 are designed to have relatively lower temperature. This Is to ensure that the condensate resulting from reheats 5/9, and/or 7/10, by stream 2, will be at a temperature low enough, which is suitable for pumping. Thus, by targeting an expansion line 1/4, followed by a series of moisture separators, and reheaters, a once through arrangement can be designed in a combined cycle application.

Fig 10B shows actual devices for a once through cycle for any working fluid such as water, ammonia or carbon dioxide, using teachings. A hot well 20, a suction stream 21, and a pump 221 are shown. A stream 22 is combined with drains 33. A stream 23 is used in a once through heat exchanger 234, using waste heat of flue gas stream 34. Working fluid stream 1 is expanded in a turbine 301, with a back pressure stream 50 at above critical pressure. As an alternate, an innovative ejector 201, with motivating fluid stream 401, and induced fluid stream 101, as one option, based upon teachings, is shown. A stream 2 provides reheat thermal energy in heat exchangers 105, and 107. A stream 51 is expanded through the remainder of the cycle. A moisture separator 103 "shakes out" moisture from a stream 3.

Drains stream 25 is pumped forward, whereas dried stream 5 is reheated in a heat exchanger 107. Reheated stream 10 is conducted to a turbine 310 for final exhaust stream 11. Drains from the reheaters 105, and 107 are conducted to a tank 31 as streams 29, and 30. A pump 233 delivers a stream 33 which is combined with the stream 22 to complete the cycle. The temperature at 23 is designed to be such that the waste stream

35 can be cooled for final discharge.

Fig 10C shows extension of the teachings regarding heat transfer reversibility as applied to heat transfer between compressed air, and products of combustion in a pressurized recuperator type of gas turbine cycle arrangement. The teachings can be applied to cases when the thermal energy regeneration is at the TAIL end, and not necessarily in an INTERMEDIATE recuperator type of cycle con iguration. The cycle per node points 1, 2, 3, 9, 11, 12, 13, and fuel streams

51, and 52, follows the previous discussions. A stream 10 represents the departure from the previous discussion. The heat capacity between streams 4, and 9 varies by about 20 % , with stream 9 having higher heat capacity. This is because the specific heat for stream 4 is about 0.24 BTU/Lb ./De .F, and that for stream 9 is about 0.27 BTU/Lb ./Deg .F. In addition, stream 9 has higher flow rate in comparison to stream 4, by about 10 to 15 % , because of fuel addition. Hence the need for diverting stream 10 for heat transfer reversibility, by matching heat capacities, per teachings. The thermal energy of stream 10 is used in a once through type of bottoming cycles 16/161, in a reversible manner, as discussed in Fig 10B. Recuperator 110 is shown to "drive" TWO cycles, 16, and 161. This is being pointed out for this, and ANY OTHER configuration that uses a recuperator. This is an important teaching. Similarly, the thermal energy of intercooler 2/3 is also used in a once through type of bottoming cycle 15, suitable for ammonia/ carbon dioxide as working fluid.

Fig 11A shows a pull-through cycle with indirect beating. The cycle also incorporates a post recuperator expansion turbine that will allow a larger amount of thermal energy to be recuperated. Ambient air 1 is moved through the cycle by a blower 301. A stream 2 is Imparted waste heat in a heat exchanger 102. A portion of stream 3 is directed to a boiler 99 as stream 4, which will cool a flue gas stream 50 to a temperature for final discharge via an induced draft fan 350. A stream 5 is heated in an intermediate recuperator 105, using partially expanded stream 9. A stream 6 is introduced into the boiler at a point 7, with matching temperatures per teachings.

Heat transfer surfaces 104, and 107 are located- in the convection, and back pass of the boiler respectively. Heat transfer surface 108 is located in the radiant section, to deliver stream 8 to a power train. A gas turbine 308 only partially expands the stream 8. An external heat sink 112 is for waste heat, and is used to drive another cycle depending upon its temperature. Products of combustion stream 16, and fuel 115 drive the entire cycle.

Fig 11B shows a topping air cycle design. A Ljungstrom type of air heater is employed to deliver 2200 deg. F air at atmospheric pressure as working fluid. A double loop is shown in case a single loop will not deliver turbine quality heated air stream for a pull-through cycle. The Ljungstrom air heaters, in this case, are supplied with pre-cleaned flue gases as the heat source. Additionally, a double wall construction for the Ljungstrom air heaters, with cooling, and with the heating basket inserts with large size passages for the flue gases (not shown) is used. An Intermittent mechanical

"pounding" to continuously rid the system of solid particles, employing a system layout with appropriate clean outs is used.

The part of the system with node points 1, 2, ....17 pertain to a subatmospheric pressure cycle as discussed in Fig 11A.

Products of combustion stream 20, combustion air stream 15, fuel 115, and burner 120 are shown. Cleaning device 121 such as ceramic filters, to clean the stream 20 is shown. A stream 21 is conducted to the "boiler" 99. Solids are removed from the system via clean out points 40, 41, 42. A flue gas stream 22 is for other appropriate use per teachings. A series of LJUNGSTROM type of air heaters 152, 153, etc. are used for heating working fluid stream 4, and 6. An intermediate loop approach with the heat transport loop 60, 61, ....68 is shown as well, to ensure a clean working fluid stream 30. An induced draft fan 350, and streams 50, 51 are shown for the flue gas system. The stream 30 is heated further in the radiant section 130 of the boiler. A flue gas stream 52 is branched from the convection pass, after solids have dropped out. The rest of the cycle arrangement is based upon previous discussion, and teachings. The air heaters

152, 153, ...176, as an alternate, are replaced by a

"stationary" air heater; in which refractory material in the form of "honey comb" design is used to deliver heated air as working fluid.

Fig 11C shows a series of weighted pistons, with wires in tension, in lieu of piston rods, for a pull-through cycle. A flue gas stream 1 is branched from the convection pass of a boiler 99. Various clean out connections for the collection of solids are shown by 101, 102, 109. Lift valves or vacuum breakers are at 103, 104, 107. Electro static precipitators are shown as 105, and 108. A vacuum chamber 40 communicates with the top side of a piston 51. Pistons 51, and 53 are both weighted, and wires 54, and 55 are substitutes for piston rods. Flue gas stream flows past the piston 53 along 153. Guides 56, crank shaft 57, 58 are connected to a common, low RPM shaft 59, for both the power piston series 50, and the work piston series 52, to drive a load (not shown). Relatively "forgiving" piston technology, with entry at bottom, for solids to drop out, for flue gas stream 1 as working fluid is shown. Solids will drop out at the various collection cones, especially at 109, as the flue gas is cooled. A valve 125 will open intermittently for emptying tank(s) 225. Tank 225 communicates with subatmospheric pressure in line 25, and atmospheric pressure with the solids discharge system. A heat exchanger 206 "drives" a bottoming cycle 30 per teachings. The arrangement can easily be transformed if stream 1 was to be pressurized.

Fig 11D shows a truncated gas turbine cycle with post recuperator expansion using indirect heat transfer. The cycles of Figs 11A, and 11D are somewhat similar, except that Fig 11A uses a pull-through cycle, whereas Fig 11D uses a pressurized Brayton cycle, with an intermediate recuperator in both cases. A gas turbine train 301, 306, 308 is the main part of the cycle based upon previous teachings. Cycle is shown by node points 1,

2 11. Pressurized recuperator 107 regenerates a higher quantity of thermal energy from stream 7 to 3. A stream 4 is heated in the convection pass of the boiler in heat transfer surface 104. A stream 5 is combined with stream 4 at a point where the temperature of "mixing" is same, to ensure reversible "mixing." A stream 6, heated in the radiant section of the boiler in heat transfer surface 105, completes the cycle. A stream 9, at atmospheric pressure, from the gas turbine 308, is used as combustion air, after being further heated in the back pass of the boiler in a heat transfer surface 110. A make up combustion air stream 60/61 is heated by the flue gas in an air heater 161. A stream 62 is combined with stream 10. Fuel 112 produces products of combustion stream 12 for a boiler 99. A flue gas stream 50, and an induced draft fan 350 show flue gas discharge. It should be pointed out that the total flue gas flow 50 is much lesser than working fluid stream 1, as discussed elsewhere. A stream 60 is make up combustion air.

However, due to fuel heat value, and other plant design parameters, some air may need to be bled off as in stream 109, and/or stream 60 can be adjusted to optimize the cycle.

Fig HE shows a pull-through cycle of Fig HA, and pressurized cycle of Fig 11D, with intermediate recuperator, to form a composite cycle. The pull-through cycle based upon teachings, and cycle of Fig HA is represented by node points

1, 2 17. The pressurized part of the cycle is shown by node points 51, 52, 60. Flue gas stream 80/81, an induced draft fan 351 are shown. A pressurized recuperator 152 delivers a stream 54 which must enter the heat transfer surface 153/154 where the temperature is equal to ensure reversible "mixing" based upon teachings. A post recuperator expansion gas turbine

358 expands a diverted stream 56 to atmospheric pressure as a stream 60 for use as combustion air. For the pull-through cycle, ambient air is drawn into a blower 301, with a main gas turbine 308, and a post recuperator expansion gas turbine 310.

A heat exchanger 112 is for external cooling to reduce the duty of a compressor 313. The overall cycle is based upon teachings, and other components per Figs HA, and 11D. Thus Fig HE represents a water free power cycle. The pull-through cycle is

"driven" by the radiant section 103 of the boiler. This section of the boiler, is at very high temperature, and offers technological challenge; which is off set to a large degree, by the use of atmospheric pressure working fluid. A pressurized air cycle, starting at stream 51, is "driven" by the remaining thermal energy of the boiler. The temperature at point 53 is designed such that stream 80 can be cooled to slightly above dew point. Other variations such as reheat, post recuperator expansion, supplementary firing etc. can be considered to optimize the design, based upon teachings. Additionally, intermediate recuperators 152, and/or 102 can be designed to

"drive" liquid cycles as well, based upon teachings, as an opt ion .

Fig 11F shows another application of post recuperator expansion, and applies to a closed cycle, using helium as working fluid, such as for a High Temperature Gas-cooled Reactor (HTGR). In the current technology, net power send out is when a turbine 305 expands to the pressure of stream 1, or equal to the suction side pressure of a compressor 301. Per this invention, it is modified to be (5/6) + (7/8). Process (7/8) is post recuperator expansion. A turbine 304, and a compressor 301 circulate working fluid through the cycle. Thermal energy is supplied by a reactor 99, and waste heat rejection from the cycle is via a heat exchanger 108, using circulating water 9.

Fig 12A shows a composite cycle, coupled through indirect heat transfer in reversible manner. Load A, driven by an indirectly heated, pressurized air cycle, a pressurized recuperator 105, and post recuperator expansion is shown. The cycle is designed for exhaust stream 10 to be at atmospheric pressure. Note the "piggy backing" of the SECONDARY HEAT (3500 psi steam) via a heat exchanger 110. Ambient air stream 1, and compressed air stream 5, via intercoolers 101, and 103, and compressors 202, and 204 is shown. The stream 5 is heated in a pressurized recuperator 105. A stream 6 is further heated via indirect heat transfer in a heat exchanger 115 using boiler thermal energy. A stream 7 at about 1700 Deg. F is expanded in a truncated gas turbine 207. A stream 8 imparts thermal energy in a pressurized recuperator 105. A cooler stream 9 expands to atmospheric pressure in a gas turbine 209. A stream 10 is heated in a reversible manner, using steam at above critical pressure in a heat exchanger 110. A stream 11 is further heated through indirect heat transfer in the boiler 99, and becomes a heat transport loop, stream 12. A stream 14 "drives" a very high temperature, and pressure steam cycle via a heat exchanger 114. A stream 13 "drives" the air cycle through indirect heat transfer via heat exchanger 115 as discussed before. The streams 15, and 16 are recombined as stream 17, for combustion air for the boiler 99.

Load B is driven by a very high temperature, and pressure steam cycle. The design conditions can be of the order of 7000 3S psi, and 1400 Deg. F, because of a clean (non-hostile) thermal energy source in the heat exchanger 114. A hot well 50, and pumps 251/252 deliver very high pressure stream 52, which is combined with streams 61, and 54 from reversible heating portions of the cycle In a heat exchanger 160. A stream 56 is further heated in the heat exchanger 114. A stream 57 expands in a steam turbine 357, with an above critical back pressure.

Streams 62, and 60 provide reversible heating. A stream 59 completes the cycle in a turbine train 259/269/271, with reheaters 168/170. A stream 72 into a condenser completes the cycle. A stream 60 provides reversible feedwater heating of a stream 55. A stream 62 provides reversible heating of combustion air in a heat exchanger 110. A liquid stream 63 is returned by a pump 263. A stream 65 provides reversible heating for the ammonia cycle, in a heat exchanger 133. Liquid drain 66 is returned by a pump 266.

Load C is driven by an ammonia cycle, using above critical pressure steam, 3500 psi, as the heat source. A hot well 30, pumps 231/232, a heat exchanger 132, and a turbine train 234/237 constitute the main part of the cycle. Streams 32/33 are heated In a reversible manner. Reheat thermal energy 36/37 is provided by a diverted flue gas stream 80 in a heat exchanger 180. Streams 81, and 83 are combined, to be used in a heat exchanger 184, to drive a once through cycle. An induced draft fan 284, and a discharge stream 85 are shown.

Fig 12B shows a composite cycle, similar to Fig 12A, with loads driven depicted with the same designations. An additional load D, using a premium fuel gas turbine cycle, with a pull- through cycle at the tail end is Introduced. An indirectly heated pull-through cycle driving a load K is also part of the composite cycle. A steam cycle at atmospheric pressure, and very high temperature, with its exhaust as heat transport loop, is also part of the composite cycle. In addition, the two two- phase cycles are shown with topping innovative ejectors. A boiler primarily heats fluid streams, either at atmospheric pressure to very high temperature, or at pressures, and temperature which represent mature technology.

Load B is driven by a water cycle with very high temperature, and pressure design conditions for stream 1, as motivating fluid. A stream 13 as induced fluid for a topping ejector 113, delivers a "mixed" stream 2, above critical pressure. A stream 14 is diverted for reversible heating, whereas a stream 3 is working fluid for the cycle. The node points 3, 4, ..9, 10 represent a triple reheat steam cycle. A stream 7 at about 500 psi, is heated to about 1000 Deg. F in the back pass of a boiler 99. A stream 6 at about 200 psi, is heated to about 1700 Deg. F in the convection pass of the boiler - A stream 8, also serves as the heat transport loop for the topping water cycle via a heat exchanger 108. The pressure, and temperature of stream 9 is designed to be such that the exhaust stream 10 from a steam turbine 309 is at near atmospheric pressure, and slightly superheated. The stream 10 provides a low temperature heat sink for the back pass of the boiler. A stream 31 is conducted to the radiant section of the boiler, and is heated in a heat transfer surface 93. The very high temperature, nearly atmospheric pressure steam, stream 32, say at 2000 Deg. F, is conducted to a steam turbine 332. A stream 33, still at very high temperature, serves as the heat source for the topping steam cycle in a heat exchanger 133. A stream 11 is finally expanded in a steam turbine 311 for final discharge at about 1 psiA, and is nearly saturated, to complete the cycle. If the thermal energy need of heat exchanger 133 is not met by the thermal energy content of stream 33/11, stream

12 is recompressed to atmospheric pressure, by a steam compressor, and path 10, 31, ...12 repeated, for full flow or partial flow of the recirculated stream, based upon teachings.

The key is to have "innovative thermodynamic" tools to optimize the cycle, for maximum benefits.

Ambient air stream 51, a forced draft fan 351, and node points 52, 53, ....p ovide preheated combustion air for the boiler. Combustion air is heated in a reversible manner by a stream 15 at above critical pressure, in a heat exchanger 114. A stream 54 is combined with a stream 73 for use as combustion air. However, a stream 76 is diverted to a heating surface 94 in the radiant section of the boiler. A stream 77 is expanded in a gas turbine 377, with an exhaust stream 78 to provide thermal energy for an ammonia cycle, in a heat exchanger 178. A stream 79 is recompressed by a compressor 379. Air streams 80, and 53 are combined.

Load C driven by an ammonia cycle, with a hot well 35, a single stage feedstream heating in a heat exchanger 147, using an above critical stream 37. Stream 38 is heated by waste heat from a pull-through cycle. Stream 39 is heated by steam at above critical pressure in a reversible manner. Stream 40 is heated by the waste heat from yet another pull-through cycle.

These three heated fluid streams are recombined into a stream

44. A topping ejector 146 recirculates stream 46, to deliver a working fluid stream 45. Streams 47/48 are at above critical pressure. The expansion is completed in turbines 345/349. A bleed stream 49, at subcritical pressure, is shown for preheating feedwater in the water cycle. The ammonia drains are returned via a stream 149, which are reintroduced into the cycle via a pump 249.

Load D is driven by a gas turbine part of the cycle, which is shown by node points 60, 61, 62, ....and 68, lntercoolers 84/85, and compressors 361/362. A stream 65 is heated by an exhaust stream 68. A fuel stream 81, and pump 381 deliver a stream 83 into a combustor 183. A stream 68 from the gas turbine 367 is at subatmospheric pressure. The cooled stream 69 is recompressed by a compressor 369 to complete a pull-through cycle .

Fig 12C pertains to an ammonia/water cycle, with a water topping cycle, for low temperature application. The heat source for the ammonia cycle is regenerative bleed stream from the steam cycle, INCLUDING the main steam. The water cycle has a condenser for the waste heat discharge. However, the ammonia cycle is TRUNCATED at the above critical pressure. A hot well

30, node points 31, 32, 37, bleed stream stages 90, 91,

92, 93, and a high pressure feedwater heater with bleed stream 94, form the main part of the water cycle. Condensate, and feedwater pumps 231/237 are shown. A stream 49 is heated by a nuclear reactor. A stream 56, and a moisture separator and reheater 153/156, are shown. Streams 59/60 complete the cycle. Reheater drain 55 is collected in a tank 155, and cooled in a topping drain cooler 147. In the ammonia cycle, a turbine 306, a stream 6, and exhaust streams 7/9 are at above critical pressure. The stream 7 heats a stream 2 in a heat exchanger 102. Liquid drains 8, and 11 are combined into a stream 1; and is pumped by a pump 201. Stream 9 is cooled successively by modulated condensate, and feedwater streams, 38/43, from the water cycle; and involves ONLY the SENSIBLE heat, because the temperature rise in heat exchangers 138, 143 is such that the water streams remain liquid. Streams 43, and 38 are used in heat exchangers 143, and 138, modulated by control valves 139, and 144 respectively. These control valves can be on either side of the heat exchangers, i.e. in the inlet or the outlet stream. A stream 3 heated in a regenerative manner using subcritical bleed streams 95, and 96, and main steam stream 52.

Liquid drains 97, 98, and 99 cascade to the corresponding

"parent" feedwater heaters of the water cycle, for a singular drains level control. The water, and the ammonia cycles are thus coupled via INDIRECT heat exchange between the two cycles.

Fig 12D shows another ammonia/water cycle, and should be reviewed in conjunction with Fig 12C. The main departure is that the ammonia cycle is expanded to about 200 psi, a pressure suitable for the waste heat sink. The water cycle is truncated at a pressure compatible with the lowest stage of regenerative heating for the ammonia cycle. For ammonia cycle, a hot well 1, and node points 2, 3, ....9 show single stage feedstream heating. A stream 10, pumps 202/211, a heat exchanger 105 are per the previous discussion. A heat exchanger 103 imparts superheat energy of stream 17 to a stream 3. Streams 13/10 are at above critical pressure. Streams 13/16, and 6/9 are heated in a regenerative manner using bleed streams 41/42, and main steam stream 40. Drains 90/91/92, and 80/81/82 are cascaded to the "parent" feedwater heaters in the water cycle. The other components for the water, and the ammonia cycle are based upon the previous discussion. The main difference is whether the ammonia or the water cycle is truncated. Other variations, such as additional bleed stream points in either or both cycles; with coupling of the two cycles through INDIRECT heat transfer, is used to optimize the combined cycle.

Fig 12E shows a single stage feedstream heating concept based upon the discussion of Figs 3A, and 3B. A hot well 1, and node points 2, 3, 4, 5 show reversible feedwater heating. Pumps 203/311 deliver a stream 4 for reversible heating in three parallel paths 41, 42, and 43. A separate stream 13, preheated in regenerative manner, by bleed streams 30/31/32 is shown. A stream 14 is thus diverted for flue gas cooling, to a temperature above dew point. Streams 33/34/35, with stream 33 introduced BELOW water level, to avoid flashing is shown. Stream 14 is modulated via a control valve 114 to impose heat transfer reversibility in flue gas cooling in heat transfer surface 16, in the back pass of the boiler 99. Streams 5, and 17 are combined as stream 6, to be heated in the radiant section of the boiler. Stream 7 at very high temperature, and pressure, "drives" a turbine train 301, 302...304. The steam turbine 301, back pressure, exhaust streams 8/19 are at above critical pressure. Streams 8/20 heat streams 4, and 21 in a reversible manner. Combustion air stream 60, 61, ...64, and a forced draft fan are shown. The remaining turbine train follows a double reheat cycle. Fuel 98, products of combustion 64, flue gas stream 65/66, and an induced draft fan 265 are shown.

Fig 12F pertains to coupling of a subcritical (water) cycle with above critical ammonia, carbon dioxide or water cycles; with above critical pressure cycle, for reversible feedstream heating. A load S driven by subcritical steam cycle, and a load N driven by an above critical ammonia cycle will aid in following the various parts of the combined cycle. However, the entire power train can be designed to drive a single load. The ammonia cycle turbine 275 has above critical back pressure in streams 176, 76, 77, 78. A hot well 1, and pumps 202/203 deliver a stream 4 for the subcritical water cycle, with double reheat in a conventional configuration. A stream 5 is heated in a regenerative manner by bleed streams 9/10, with liquid drains 11/12 cascaded to the hot well 1. Drain 12 is introduced below the water level. A stream 13, at about 200 deg. F, is modulated by a temperature control valve 108. Heat transfer surface 14 is thus a variable duty economizer, which delivers constant stack temperature at 58. Heating of stream 5 to about 200 Deg. F can very well be accomplished by bleed stream at below critical pressure from the ammonia, carbon dioxide cycle, based upon optimization. Stream 6 is heated in a heat exchanger 106 by an ammonia stream 76. Stream 16 designed to remain liquid, to ensure reversible heat transfer. The stream 16 is combined with a stream 15 to follow the rest of the below critical water cycle as in node points 17/18/19 25/26. For ammonia cycle, a hot well 70, pumps 271/279, and a suction line 71 are shown. Streams 72, 73, ...79 are the main part for the ammonia cycle, based upon teachings. Streams 6, 54, and 72 are all heated in a reversible manner. A stream 73 is heated in the back pass of a boiler. Liquid drains 81/82 are collected in a tank 181 to complete the ammonia cycle. The rest of the cycle is based upon teachings .

The above discussion applies to an ammonia cycle providing reversible feedstream heating for a subcritical pressure water cycle. The teachings can easily be applied for a combined cycle constituting of a subcritical pressure water cycle with an above critical pressure water cycle as well, for reversible feedstream heating. The ammonia part of the cycle can be substituted by a water cycle, with above critical pressure at streams 76/77/78. The temperature for stream 76, and terminal temperature difference for heat exchanger 106 should be designed to ensure ONLY sensible heat transfer, i.e. stream 16 should remain liquid. In addition, a heat exchanger 121, to preheat a stream 20, and simultaneously cool stream 122 is shown. A return stream 123, substantially cooled, is used in the heat exchanger 106, as before; as in the ammonia cycle. The purpose of subcritical pressure part of the water cycle, and above critical pressure water cycle for reversible heating is to use more mature technology to the maximum extent. An ENTIRE cycle with very high temperature and pressure design conditions, using water as working fluid, may be technically challenging. It should be emphasized that the temperature at 16 can be about 650 deg. F, for a 2400 psi pressure water cycle.

We can accomplish the sensible heat transfer only, by imposing a large terminal temperature difference in heat exchanger 106, thus eliminating the need for the heat exchanger 121, if so desired. Another variation, based upon teachings is to replace the turbine 275 by an innovative ejector 290. This ejector with motivating fluid stream 90, and induced fluid stream 91 is shown. Stream 92 MUST however be designed to be at above critical pressure. The stream 92 is functionally similar to streams 176/76/77/78. Induced fluid stream 91 can be designed to branch from a large number of places in the subcritical water cycle, such as 220, and 221 amongst others, to optimize the cycle.

Once more referring to Fig 12F, working fluid for the above critical pressure part of the cycle, with turbine 275, can very well be carbon dioxide. The above critical pressure carbon dioxide streams 81, and 83 will need to be further cooled by an external cooling source, perhaps refrigeration, In heat exchangers 181, and 182. The streams 81/83 can be combined for cooling, or a single stream 71 can be cooled instead.

Once more in Fig 12F, for part load operation, system alignment is shown via streams 30, 31, 32, ...38. An innovative ejector 276, with induced fluid stream 376, from streams 31,

32, 33 is shown. This ejector provides a variable resistance, to ALWAYS get above critical back pressure in streams 176, 76,

77, 78. The additional path, via a turbine 230, with back pressure in stream 33, of the order of 200 p i for ammonia cycle is provided. This is to "bleed" away from stream 75, which is designed for full load operation, and maintains sufficiently constant flow. As the demand for flow in streams

76, 77, 78, combined, decreases with load, the additional path via the turbine 230 is summoned. An additional method to vary the flow in stream 176, or any other part of the cycle, for part load operation, is to vary the duty, or the capability of heat transfer of heat exchanger 106, 154, and single stage heating heat exchanger for streams 72, 79. Refer to Fig 2H as well, for this discussion. The liquid level 991 is varied by using the valve 111, thus varying the overall heat transfer coefficient of heat exchanger 41. Thus the heat transfer capability, of heat exchangers as listed above, is varied via liquid level variation. A controller (not shown) thus is used to

"orchestrate" the cycle parameters for part load operation.

Heat exchangers 135, 136, 137 are for regenerative heating of stream 35, by bleed stream from water, and/or ammonia cycle, based upon teachings. Thus by combination of ejector 276, and the additional path 30, ..38, part load operation is shown, to ensure reversible heating in the various heat exchangers as shown. The very high pressure turbine 275 is located at the foot of the boiler 99, to reduce the high pressure piping length for stream 75. The coupling of the two cycles discussed above is also possible with above critical pressure water cycle, with above critical pressure ammonia cycle, based upon teachings. Any number of variations in terms of design pressure and working fluid used, for either of the cycles, for the combined cycle configuration, can be formulated, based upon teachings .

Fig 12G is for further clarification of the heat transfer reversibility of Fig 12F. Steam at above critical pressure, and cold reheat, and feedwater streams all have different heat capacities. The arrangement shown is to clarify that heat transfer reversibility can still be imposed, without having to

"evaporate" the feedwater stream, at subcritical pressure, i.e. non sensible heat transfer. As discussed before, for heat transfer reversibility, ONLY sensible heat transfer should be conducted. A terminal temperature difference of 0 Deg. F is used for simplification of discussion. A stream 2, at above critical pressure heats a cold reheat stream 50, and a subcritical pressure water stream 61, in series, by equating heat capacities. Diverted streams 63, and 22 are matched with a stream 10 for equal heat capacities as well. Heat exchangers

125, and 109 are based upon previous teachings. A careful review of the various temperatures on Fig 12G, further clarifies the exercise, which is used, to match heat capacities, in order to impose heat transfer reversibility.

Fig 12H shows a modified expansion line for a subcritical pressure water cycle, which will be coupled with an above critical pressure water cycle, for feedstream heating. The expansion line for the high pressure turbine of the subcritical pressure water cycle, is extended, so that cold reheat is at a much lower pressure, and temperature. This cooler cold reheat stream is thus more suitable, as a heat sink, for the above critical pressure steam, from the above critical water cycle, for reversible heat transfer. The second reheat, 16/17, to very high temperature at 17, is for subsequent discussion. The purpose of a lower temperature cold reheat stream 8 will become clearer from the subsequent discussion of Fig 121.

Fig 121 shows a modified subcritical pressure Rankine cycle, with the same nodes of the expansion line as in Fig 12H. A hot well 1, and node points 1, 2, ....11 depict the main cycle. A stream 56 from an innovative ejector 155 is at above critical pressure. Stream 3 at subcritical pressure, and cold reheat stream 8, are both heated in a reversible manner. A hot well 50 for the very high pressure, and temperature cycle, with node points 51, 52, ...56 is per previous teachings. A stream 53/54, after being heated in a reversible manner, is superheated in the back pass of the boiler, in heat transfer surface 154. A stream 55 "drives" the innovative ejector 155. The motivating fluid for the innovative ejector 155 can be one or more of streams 70/71/72, or any other "gas" stream from the "parent" water cycle. The "mixed" stream 56 is designed to be at above critical pressure. Streams 57, 58, and 59, heat streams 53, 3, and 8 respectively in a reversible manner. Heat exchangers 103, and 108 are configured to be in parallel, to simplify the use of streams 58/59. Refer to teachings of Fig 12G, for variations. A heat exchanger 158 is shown as an example, with combustion air stream 79 as the heat sink, to "cool" stream 58.

This is to ensure sensible ONLY, heat transfer in heat exchanger 103. The air heater 175, and associated streams are shown. It is important, once again, that the stream 4 remains liquid, to ensure ONLY sensible heat transfer for reversible heating, per teachings.

Fig 12J shows a single working fluid combined cycle, with both the cycles using carbon dioxide. A very high temperature, and pressure topping carbon dioxide cycle is "driven" by a boiler 99. The waste heat of this cycle then "drives" a carbon dioxide cycle as the bottoming cycle. Both the cycles have above critical pressure reversible heating of working fluid stream. A stream 20, at very high temperature, and pressure "drives" a carbon dioxide turbine 320, with above critical back pressure in a stream 30. This stream 30 provides reversible heating in heat exchangers 121/130. A stream 65 from a hot well 1 is in liquid form. A stream 31 is combined with stream 23 for cooling in heat exchanger 124 using circulating water, heat exchanger 125 using a refrigeration cycle. If streams 23/31 have sufficiently high grade thermal energy, a heat exchanger 123 can actually "drive" the refrigeration cycle itself, for use in the heat exchanger 125. A stream 21 "drives" a bottoming cycle of turbine 305, using carbon dioxide as working fluid as well. A hot well 1, node points 2, 3, ....7, and heat exchangers 103/121, for reversible heating, form the main cycle are shown. A combustion air stream follows nodes 70, 71, 72 with fuel stream 173, and products of combustion 73. Flue gas stream 74, a reversible air heater 171, provide a diverted stream 77 per teachings. The stream 78 heats a stream 80 in a heat exchanger 177. A stream 81 is further heated in a heat exchanger 181 using stream 22 from the topping cycle, in a heat exchanger 181. The stream 23/31 is cooled to liquid form, a stream 26 as discussed before. The flue gas to combustion air heating in ah 171 can be "de-coupled." Both the resulting streams, combustion air as well as flue gas, are then designed for reversible heat transfer, with carbon dioxide streams, from suitable parts of the cycle, based upon teachings; and as in other parts of the discuss1on.

Fig 12K shows another version of the carbon dioxide / carbon dioxide combined cycle. The two cycles of Figs 12J, and 12K are identical except for turbine 320. In Fig 12K, the ENTIRE exhaust stream 21 from the topping cycle "drives" the bottoming carbon dioxide cycle of turbine 305. The node points, as well as the component numbers in the two Figs are identical. The air heater 171 is not shown to be reversible, for simplification only. However heat transfer reversibility can be imposed upon this air heater as well, or flue gas to combustion air heating

"de-coupled," using teachings.

Fig 12L is based upon teachings of Fig 3H, and is an extension of the cycles of Figs 12C, and 12D. The main feature is MULTI stage, reversible feedwater stream heating for low temperature cycles. The water part of the cycle is shown by node points 1, 2, ....11, with moisture separator and reheater at 108/109. The ammonia cycle is shown by node points 40, 41, ....43. Fluid streams 50, 51, 55, and 43 from the ammonia cycle provide reversible heating of water cycle streams 3/4, and ammonia cycle streams 58/59. Main steam streams 26, and 27 of the water cycle provide thermal energy for the ammonia cycle. A stream 32 is for water cycle reheater. Drains 12/14 from the moisture separator, and reheater, respectively, are cooled in a reversible manner in heat exchangers 112, and 114 respectively. The streams 19, and 20 are reintroduced into the feedwater stream as shown, or by matching temperature based upon teachings. Reversibility is imposed in heat exchangers 103, 104, 155, and 143. Thus a multi (two in this case) stage, reversible feedstream heating cycle is described. Other bleed stream points on either cycle can be added to optimize the combined cycle, based upon teachings.

The discussion thus far has applied to regenerative heating of feedstream in a reversible manner. However the teachings, pertaining to reversible heating/cooling, can be applied to parts of an ENTIRELY SUBCRITICAL, conventional Rankine Cycle, with a multitude of feedwater heating stages; first, understanding the following features:

Decouple flue gas to combustion air heating.

Heat both combustion air, and feedwater streams, in a regenerative manner, using latent heat of ALL the bleed stream stages .

Impart superheat of bleed stream, where applicable, to a modulated flow of combustion air, and/or feedwater/condensate fluid streams in a REVERSIBLE manner. Prewarm combustion air using WASTE HEAT of condenser steam.

Cool flue gases, leaving the economizer, in a REVERSIBLE manner, via modulated flow of condensate/feedwater streams.

Cool heater drains, for the ENTIRE heat load, in the corresponding feedwater heaters, preferably in a vertical configuration of straight tube construction.

Fig 13A shows a turbine 301, a bleed stream 3, a combustion air stream 90, a feedwater stream 20, and a fuel oil/gas stream 91. Combustion air, feedwater, and fuel oil streams, are ALL heated by the latent heat of bleed stream in heat transfer surfaces 104/105/106 respectively. Superheat of bleed stream, 3/31, is imparted to a modulated feedwater stream 21 in a reversible manner using a control valve 121, and temperature signals 50/51. The temperature at 51 is designed to be below the saturation temperature for stream 23, for sensible heat transfer ONLY. A NEARLY SATURATED stream 6, and drains 7/8 are cascaded to a two zone feedwater heater 106. EACH stage of bleed stream, thus, heats ALL the streams in a regenerative manner. Superheat, sensible thermal energy is used in a REVERSIBLE manner. Liquid drains are cascaded to the "parent" feedwater heater for a singular drains level control.

Figs 13B, and 13A are similar except that superheat of bleed stream is imparted to a split flow of combustion air stream 21, in a heat exchanger 150, instead of feedwater stream, as in Fig 13A. A control damper 121 receives temperature signals 50/51 to impose heat transfer reversibility in heat exchanger 150. An enlarged pipe section 11 is provided for capacitance for the drain cooling zones for feedwater heater 106, applicable for both the Figs .

Fig 13C shows combustion air heating, by applying teachings of Figs 13A, and 13B. Heater drains are cascaded to corresponding 2-zone heaters. The designations shown are "L" for liquid, "S" for steam, and "SH" for superheat. Combustion air flows in a downward direction to permit a more efficient design, by eliminating subcooling of liquid drains, inside the steam coils. This subcooling, if permitted, as in a design with upward flow of combustion air, would continuously result in varying heat load of the steam coils, thereby causing flow oscillations, in order to meet heat loads. A forced draft fan 51 draws combustion air 51. A stream 52 is heated in finned tubes 63, which communicate DIRECTLY with the condenser, via steam stream 54, and forms an INTEGRAL part of the main condenser 56. Liquid stream 55 drains back. First few rows of finned tubes 60 are insulated at the bottom, as shown at 61, to prevent freezing. Downwards flow of combustion air, by design, will also prevent freezing. Saturated steam streams 1/3/4, steam coil 2, a feedwater heater 5, with a drain cooling zone

6, and subcooled drains 7, as shown, provide a heating stage for combustion air stream 80. In a similar manner, a superheated steam stream 8, and a steam coil 9/10 with two heat transfer sections pertain to a heating stage for combustion air stream 81. Section 9 is the condensing section, and a section

10 is desuperheating section, which heats a split stream 11, in a reversible manner, via a temperature control damper 12, per teachings of Fig 13B. Liquid, and steam is conducted to a feedwater heater 51 via a line 13. Slip stream 15 is introduced into the full flow of combustion air stream 80/81/82/83, at a place that has temperature equal to or lesser than the temperature of stream 15. Heater drains 16 from higher heating stage is introduced BELOW the water level in feedwater heater

51 per teachings. Subcooled drains 17 are conducted to the next feedwater heater. A final heating stage has superheated stream

18, a desuperheat ing section 19, a condensing section 20, an equalizing line 21, to heat combustion air stream 82. A corresponding feedwater heater 22 follows the previous discuss ion .

Fig 13D shows variations to combustion air heating for start up, and part load operation. This is necessary, because, the final combustion air temperature, in regenerative heating arrangement of Fig 13C, depends upon the pressure of final bleed stream. For start up, this heating source is not available at all. For part load operation, the final combustion air temperature that can be achieved through regenerative heating only, may not be high enough for coal drying, or other combustion requirements. Therefore, an external or supplemental heat source may be necessary. An auxiliary steam stream 5, an

ON/OFF valve 6, or a premium fuel, for in duct combustion 8/9 is shown. Another option is high pressure main stream 2, which is used via a throttling device, such as a restriction orifice, or an ejector 102. The stream 2 is motivating fluid for the ejector 102, to be "mixed" with the cold reheat stream 3 as induced fluid 3, to deliver the desired pressure at 10. The ejector option is the most efficient method, however, not the simplest .

Fig 13E shows REVERSIBLE cooling of flue gas stream 1, leaving the boiler, using modulated condensate/feedwater streams. Condensate stream 4, is combined with a condensate stream 5 to yield a constant temperature stream 3, at say 200 Deg. F, via a temperature control valve 6. The stream 3 is used in a low pressure economizer 7. Similarly a stream 8 is diverted for a high pressure economizer 9. The economizers 7, and 9 cool the flue gas stream 1, in a REVERSIBLE manner, via the use of modulating temperature control valves 10, and 11. These valves receive temperature signals as shown by dotted lines. When the temperature in stream 1 will result in a phase change of stream 12, i.e. steam formation, an extra step is shown. This is for cycles when stream 12 is at subcritical pressure. In such cases, an unregulated, partial flow economizer 14 is added. A final feedwater stream 13 is induced by a diverter ejector 15. A high pressure economizer surface 14, with heated stream 140 is added as shown. This will result in cooling of the flue gas stream 1, so that the temperature at point 16 will ensure reversible heating in the high pressure economizer 9, i.e. sensible heat transfer only. The temperature for flue gas stream at 16 is designed, such that stream 12 will remain liquid for subcritical pressure cycles. This approach is used for deletion of the full flow economizer in the boiler. In addition, the flue gas cooling arrangement shown will yield constant stack temperature over the entire load range, through the use of VARIABLE duty economizers 7, and 9. The various temperatures shown are for guidance only, and do not show an actual design.

Fig 13F, shows a conventional Rankine cycle per node points

51, 52, 63. Flue gas stream follows node points 80,

81, 83, and combustion air stream follows node points 70,

71, ....73. A flue gas stream 82, along path "A" is designed to be cooled below dew point temperature. A condensate stream 3, from a hot well 1, is transferred to an overhead tank 103, using a low head pump 202. A stream 4 flows downwards, to a tank 107, via gravity, and upwards via condensing heat exchanger tubes 105. The flue gas stream 82 flows past the heat exchanger 105, in a cross flow or parallel flow arrangement, or some combination thereof. The heat exchanger 105 is thus subjected only to atmospheric pressure. As an alternate, the flue gas stream 82 can follow path "B." In this configuration, tanks 103', and 107' can be thus arranged, to delete pump 202.

The hot well 1' is located to be higher than tank 103', thereby providing the required pressure through static head. Another path "C" uses very large pipe heat exchangers 1105, 1106, which have flue gas stream 182, 183 flowing as shown. Tanks 1103,

1107 are functionally same as tanks 103, and 107 respectively.

The heat sink, condensate flows through the annulus space as shown by streams 1040, 1050, 1060, and stream 1070 follows the rest of the cycle.

Fig 13G shows the innovative cycle in a composite diagram. Use of bleed stream superheat, in reversible manner, as in Figs 13A, and 13B is not shown here, solely for simplicity. A prewarmed combustion air stream 22 is heated in a regenerative manner in a duct 200 using ALL the bleed stream stages, per Fig 13C. A heated stream 23 is delivered to the boiler via a heat transfer surface 124, to further heat the combustion air stream 23 for start-up, and part load operation. Similarly, flue gas stream 40 is cooled in a duct 300 using diverted condensate, and feedwater streams in a reversible manner, per Fig 13E. A flue gas stream 41 is delivered to the induced draft fan 241. The condensate, and feedwater streams 2, 3, ..11 are heated in a regenerative manner. Drains (not shown), from combustion air regenerative heating in duct 200, are cascaded to the "parent" feedwater heaters, for a singular heater drains level control. Additionally, the cycle arrangement shown, lends itself to a very high pressure feedwater heater, (heater above the reheat point- HARP), with less technical challenge, to further enhance thermal efficiency.

Fig 13H shows cross section of a power plant for major components of the energy conversion system. The components are arranged in columns, in the vicinity of each other, since the systems are coupled thermodynamically. Two zone, vertical, straight tube, feedwater heaters are utilized to cover distance, thereby reducing the cost of piping. The cycle lay out follows node points 1, 2, 3, 13. Low pressure heaters 101, 102, 103, and high pressure heaters are 104, 105, and 106, and a deaerator heater 206 are shown. Flue gas stream 80/82, and combustion air stream 70/72 are located along side the condensate, and feedwater train. Heater drains are introduced BELOW the water level per teachings.

Fig 131, shows a retrofit arrangement based upon teachings. Heat transfer reversibility is imposed in air heater 183. Cycle follows node points 1, 2, 14. Flue gas, and combustion air fluid streams are per node points 80, 81..and 70, 71.. respectively. A stream 81 is diverted around the air heater 183 to impose heat transfer reversibility per teachings of Fig 2C. Diverted flow in stream 81, based upon equal heat capacities of streams 73, and 82, will come out to be about 20% of flow of stream 80. Low grade thermal energy of bleed stream, is imparted to the combustion air stream 72, via steam colls 50, and 51..., in a duct 272. Liquid drains 60/61 are cascaded to the "parent" feedwater heaters 103/104. The diverted flue gas stream 81 is cooled in a reversible manner, in a duct 300, per teachings of Fig 13E; using diverted condensate, and feedwater streams 30,31, ..., and 40, 41, ...respect ively. Thus, low grade thermal energy is imparted to the full flow of combustion air stream, in duct 272, and heat transfer reversibility is imposed on the air heater by diverting the "excess" flue gas flow via stream 81. This diverted flue gas stream is then cooled in a reversible manner in a duct 300. At 82, or other suitable place, a passive resistance (not shown) is added, if needed, to divert flue gas stream 81.

The heat transfer reversibility is an important thermodynamic objective. In the case of a power plant however, the thermal energy of flue gas stream 85 is "thrown out of the cycle." Because of this, an optimization exercise is shown via Fig 2C, heat exchangers "D, " "E, " and "F." The flue gas has specific heat of 0.27 BTU/Lb./Deg. F, and for combustion air it is 0.24 BTU/Lb./Deg. F. In addition, the flue gas flow is about 10 % more than that for combustion air, due to addition of fuel. For a given temperature of 100 Deg. F for combustion air, and 600 Deg. F for flue gas, various values are shown in heat exchanger "E" for an actual ah. Both flue gas, and combustion air are FORCED into the ah as shown. In the heat exchanger "D, " heat transfer reversibility is IMPOSED, and various values are as shown, including the diverted stream, about 19 % of full flue gas flow. In heat exchanger "F, " a larger amount of flue gas flow will be required to be diverted, to match the energy transferred; because combustion air inlet temperature into the ah is elevated to 200 Deg. F. Thus, by fixing the combustion air outlet temperature at 533 Deg. F, and flue gas outlet temperature at 250 Deg. F, we can optimize the cycle to maximize the benefits, by maximizing the low level bleed stream thermal energy imparted to combustion air inlet stream, in a regenerative manner. Thus, even though heat transfer reversibility is an important tool, the fact that flue gas thermal energy is "thrown out" of the cycle, points in the direction of optimization. FORCING the FULL flow of BOTH combustion air, and flue gas streams into the ah, as in heat exchanger "E, " is, for sure, a "poor" design. The benefit can be drawn by imparting MAXIMUM QUANTITY OF LOW GRADE thermal energy to combustion air inlet into the ah. The ah size, and other plant parameters can then be used to optimize the design.

The teachings based upon this INTENTIONAL departure from heat transfer reversibility are to be applied to SIMILAR situations, when optimizing the cycle design.

Fig 13J shows superheat of bleed stream being imparted to diverted streams of condensate, and feedwater in external desuperheaters . The cycle follows node points 1, 2 14.

Superheat thermal energy of bleed stream 20 is imparted to a diverted condensate stream 30, in a heat exchanger 120, via a diverter ejector 60. Other bleed streams 21, 22, 23 follow the teachings thus developed. An optional control valve 137 for the top bleed stream is shown to impose heat transfer reversibility in heat exchanger 123 per teachings of Fig 13A. For the feedwater heater 108, heater drains 41/42 are cooled in a reversible manner in a heat exchanger 140, by a diverted feedwater stream 50, via a control valve 250. This can be achieved either by matching the terminal temperature differences or equating the flow rates of the two streams in the heat exchanger 140, as desired. A control valve 133 is shown to impose heat transfer reversibility in a heat exchanger 121, for the deaerator heater bleed stream 21. In this case, flow path 91 is shown, instead of re-entry via a diverter ejector 61.

Fig 13K shows another arrangement for utilization of bleed stream superheat thermal energy. Bleed stream 30 imparts superheat thermal energy to a modulated flow of feedwater stream 32 in a heat exchanger 101. However, if the temperature at 34 is not equal to or greater than the final feedwater stream temperature at 14, a control system, designed to introduce stream 34 at a suitable place in the feedwater stream

9, 10, ...14 will be needed, i.e. a "smart* system will have to be developed. As an alternate, for simplification, condensing heat exchangers 102, and 103 are proposed. This arrangement will ALWAYS heat stream 34 to the temperature of final feedwater. Steam, and liquid drains, 40/41 are conducted to the

"parent" heat exchangers 102, and 103, thereby resulting in a

"dummer," simpler system. The teachings thus developed apply to combustion air heating per Fig 13C as well.

Fig 13L shows the arrangement necessary to impart bleed stream superheat thermal energy to condensate/feedwater, in a reversible manner, in two installments. It will necessary in cases when the bleed stream is in the low pressure part of the cycle; and the temperature attained for the split feedwater stream, by utilizing the superheat thermal energy of this bleed stream, is such, that it, the split feedwater stream, should be Introduced in the high pressure part of the cycle. Cycle is shown by node points 1, 2, ....22. A bleed stream 30 is cooled successively in heat exchangers 130, and 131, so that stream 32 is nearly saturated. A diverted condensate stream 50, 51, 52, and a diverted feedwater stream 40, 41, 42 are used for reversible heat transfer, in heat exchangers 131/131 per previous teachings; via modulating control valves 150/151 respectively.

Fig 13M shows a variation to the approach of Fig 13L, to address the same condition of superheat thermal energy of bleed stream 30. Cycle Is shown by node points 1, 2, 21. The discussion of Fig 13L applies, except that the feedwater stream

50, is first cooled, in a reversible manner, in a water to water heat exchanger 151, using a modulating control valve 241 per teachings. A control valve 250, however, modulates the stream 50 to impose heat transfer reversibility in a heat exchanger 130. The stream 50 thus follows stream 30, and stream 40 follows stream 50, to "reach back" for the high grade bleed stream superheat energy.

Fig 13N shows a modified expansion line 1/2/5/7/8 vs a conventional expansion line 1/2/3/4. This will enhance the benefits of the proposed cycle arrangement, in which the flue gas to combustion air heating is decoupled. The objective is to have a COOLER cold reheat stream 5. The expansion line to point

51, with a moisture separator 51/52, is also included in the discussion. In the new expansion line, the intermediate pressure steam turbine is 2/5 or 2/51 rather than 3/99. The

HIGH PRESSURE, and INTERMEDIATE PRESSURE turbines, 1/2, and

2/5, or 2/51, when designed for a "deeper" expansion line, will provide cooler cold reheat stream, 5 or 52, as heat sinks, in the back pass of the boiler. This will yield a cooler flue gas temperature leaving the boiler. Thus, flue gas cooling, outside of the boiler, by the diverted condensate, and feedwater streams, per Fig 13E, will not by-pass the entire condensate, and feedwater heater train. This will result in full flow of feedwater through the top feedwater heaters. The bleed stream flow through these heaters, will, thus, not be reduced, thereby reducing the condenser loss. There will, however, be a decrease in the intermediate pressure turbine work, 2/5 or 2/51 vs 3/99.

There will, however, be an overall efficiency gain due to reduced condenser loss.

Fig 130 shows a composite decoupled cycle, based upon expansion line of Fig 13N. Cycle is shown by node points 1,

2, 19. Combustion air heating (not shown) is per Fig 13C.

Flue gas cooling in a duct 300 is per teachings of Fig 13E.

However, the flue gas temperature at 30 is cooler than in the earlier configuration. Therefore diverted feedwater stream 38 will NOT be heated to a temperature equal to or greater than the temperature of final feedwater stream 12. We will thus introduce stream 38 into the feedwater train at say point 9, the temperature at 38 being lesser than the temperature at point 9. However, the temperature for stream 38 will vary with load. In order to have a simple system, which will always permit the reintroduct ion of the diverted stream 38 into the final feedwater stream 12, two condensing heat exchangers

139/140 are shown. These heat exchangers draw heating bleed stream from the "parent" feedwater heaters via lines 50/51, with liquid drains cascading back (not shown). Thus, temperature for stream 41, flow path 39/40/41, will always permit reintroduct ion into the final feedwater stream 12. In a similar manner, cold reheat stream 14, which is cooler than usual, per discussion of Fig 13N, can ALTERNATELY be heated, using the bleed streams 53/52 in heat exchangers 114/116' respectively. However, BOTH the options, as discussed, CANNOT be applied simultaneously. This is because, UNLESS COOLER cold reheat stream 14 is used in the boiler 99, via heat transfer surface 116, the temperature at 30 will not be lowered. Thus, we can either DIRECTLY impart the bleed stream thermal energy to cold reheat via heat exchangers 114, and 116', OR

INDIRECTLY, as in discussion above, via streams 38/39.... 1.

Fig 13P shows the devices per the variation in the expansion line of Fig 12H. The conventional expansion line will follow 5/8/10/16/11; and the departure proposed is

16/17/18/18', and 16/17/18/90*/96/11. The key is very high temperature at 17, followed by expansion 17/18, and then

"pulling back" the expansion line along 18/18', using cold reheat stream 8 as the heat sink. As an alternate, continue expansion to 90', then follow cooling 90'/96, using condensate, feedwater, and/or combustion air streams as heat sinks, as will be discussed later. The cycle has its conventional con iguration along node points 1, 2, 20. A cold reheat stream 16 is heated to very high temperature, and very hot stream 17 is conducted to a turbine 317. It should be noted that the turbine 317 is separated from the main turbine train, and "drives" its own load 417. This is to emphasize that the turbine 317 being used in a steam cycle can very well be a transformed GAS TURBINE, using steam as working fluid. The gas turbine as it exists, may require minor modi ication, and will run on steam as working fluid as well. A high temperature exhaust stream 18 is first cooled in a heat exchanger 118, using a diverted stream of cold reheat 55, and a diverter ejector 156. A stream 56 is reintroduced as shown. A final exhaust stream 90, still at sufficiently high temperature, will provide useful thermal energy for the cycle, using combustion air, and/or condensate, and feedwater fluid streams in a reversible manner. Combustion air stream follows node points

70, 71, .... 4. A stream 73, if at a temperature lower than the final bleed stream saturation temperature, is heated in a duct

200, using steam coils 63, ...64. Combustion air stream 74 is thus heated to a temperature equal to the final feedwater temperature. If stream 72 is only a partial flow of the total combustion air for the boiler, a stream 272/273 is heated by bleed stream per teachings of Fig 13C. Similarly a stream 92 is cooled in a reversible manner, based upon teachings of Fig 13E in a duct 300. The nearly saturated exhaust 96, is condensed in a condenser to complete the cycle. Thus, the expansion line

"wanders around" on the Mollier Diagram, "knowing" that combustion air, and/or condensate, and feedwater streams, in reversible heat exchange, per teachings. This, therefore, provides the "safety net," before the final heat sink for the cycle, i.e. a condenser is reached.

Fig 13Q shows a similar approach as in Fig 13P, except that a nearly ATMOSPHERIC pressure cold reheat stream 16 is heated to very high temperature in the radiant section of the boiler. The node points for the Figs 13P, and 13Q are same, to the extent possible, to draw a parallel. Thus, only the variations will be discussed here. Refer to Fig 12H as well, for understanding the modified expansion line. Continuing from the above, a hot reheat stream 17' is conducted to a turbine train 317'. The main turbine train is shown separate from the very high temperature turbine train 317', which may have to be a low RPM machine; and can be adapted from the gas turbine technology as well. Because of the very high specific volume of stream 17', several parallel paths are shown. A heat exchanger 316 is to preheat the cold reheat stream 16, before stream 16' is heated in the boiler. Streams 90, 91, .., and other streams shown, are as discussed in Fig 13P.

Fig 14A shows an improved system for boiler superheater sprays. Cycle is shown by node points 1, 2, 20. The reheater spray is sometimes branched from the boiler feedwater pump barrel as stream 40. Similarly superheater spray 60 is branched from the feedwater stream, usually upstream of the boiler feed control valve 208, to ensure an uninterrupted supply of spray water. In both cases, the spray water, streams 40, 50, is imparted secondary thermal energy of bleed streams, in heat exchangers 101, 102, 103, 104. The heat exchangers 101/102 heat BOTH the spray streams, by having a common shell side, and a divided channel (tube) side. Heat exchangers 103/104, heat individual sprays, as shown, thus allowing design flexibility. Heating steam as well as condensate are conducted via lines 60 to 63. Heated streams 43/53 are controlled using control valves 143/153 respectively. Primary/secondary superheaters 90, ...93 are shown.

Fig 14B shows the boiler blow down system improvement. Cycle is shown by node points 1, 2, 16. Economizer 110, a boiler is 99, and blow down stream 50, in one proposed arrangement follows path 51, ...54. A control valve 153 determines the rate of flow of the boiler blow down stream 54. 5S A water turbine 153 will utilize the pressure energy. The boiler blow down stream 50 is cooled successively, in a reversible manner in heat exchangers 151/152. Streams 90/92 are modulated via control valves 191/193. Stream 91, and 94 are reintroduced at 6, and 110 respectively, based upon temperature match. Variations based upon teachings, can be considered, based upon economics, and other considerations. The boiler blow down thermal energy is "piggy backed" back to the boiler on an as is basis. In one variation, path 50, 75, 172, 76, 51, ... 54 is shown. A stream 50 is first cooled by combustion air stream

72, in a finned tube heat transfer surface 172. In a variation, boiler blow down stream per path 50, 40, 41, 51, ..54 is shown.

The stream 50 is first cooled by a diverted feedwater stream

60/61, in a heat exchanger 160, using a diverter ejector 161.

Nearly saturated stream 50, is first subcooled, near the exit point from the boiler, to avoid flashing. Heat exchanger 160 is located close to the boiler exit point. A more efficient, as well as more reliable system, is shown.

Fig 14C shows a passive thermal shield for the boiler drum.

Cycle is shown by node points 1, 2, 13. A high pressure feedwater stream 60 is diverted using a diverter ejector 107. The stream 60 is first cooled in a heat exchanger 150 using a stream 50, from the low pressure condensate system, using a diverter ejector 151. Stream 61 is used between the pressure boundary 65, and internal "shell" 66, for the boiler drum. Stream 62 is reintroduced into the final feedwater stream 8. A PASSIVE thermal shield system will make the design of component 65 less technically challenging.

Fig 14D shows improved boiler feedwater pump recirculat ion system. Cycle is shown by node points 1, 2 16. A boiler feedwater pump 208 has a pump reelrculat ion line 55, which is cooled in a heat exchanger 150, by a diverted stream 50, using a diverter ejector 104, and an ON/OFF valve 103. Valve 103 can be an open valve as well. The proposed cooling arrangement is to reduce the wear, and tear on the pump recirculat ion valve (not shown). For an explanation, consider this. Stream 8 is nearly saturated. Pump 208 imparts pressure energy of the order of 12 to 15 BTU/Lb. The pump recirculat ion valve throttles this pressure energy, which appears as heat energy, due to turbulence. This results in the formation of tiny steam bubbles, which is detrimental to the pump recirculat ion valve. The proposed cooling, in heat exchanger 150 will alleviate this problem. Beyond point 56, for other part of the innovation, the pressure energy of stream 55 is dissipated via a series of parallel paths 57, 58, 59. The ON/OFF valves 90, 91, and 92 are controlled by a controller 65, to effect a desired flow rate In a stream 165. The pressure at stream 60 is dissipated, via nozzle(s) 61, by first converting pressure energy into kinetic energy, which in turn is dissipated in a tank 162. The tank 162 communicates with a storage tank 108 via line 62, and an equalizing line 63. The nozzle 61 can be located in the storage tank 108, without the need of tank 162.

Fig 14E shows an improved system configuration for the discharge of steam dumps, and non condensables into the condenser. Cycle is shown by node points 1, 2 15. Steam dumps 60 are conducted to the condenser, via a slightly pressurized tank 160, relative to the condenser. This pressure is maintained by a line 64 via a restriction orifice 164. A loop seal 61 is shown. A stream 63 condenses stream 60 in tank 160, via sprays. Supersaturated drains 62 are conducted back to the condensate stream 2 on the suction side, via gravity, and BELOW water surface. Noncondensables are removed from the condenser, using an ejector 140, via an induced fluid line 41. The motivating fluid, is main steam fluid stream 40. Current technology follows flow path 42, to a heat exchanger 103. The noncondensables 50, 51, 52 are sent to the condenser via restriction orifices, and a line 53. An ON/OFF control valve 153, a controller 55 are shown. For start-up, the non condensables follow path 53 to the condenser. After startup, a flow path 54/42 is established by realignment of valves 153/154, via controller 55. Noncondensables from some of the feedwater heaters, when at required pressure, are introduced directly into the discharge line 42 of ejector 140, rather than into the suction line 41, via the condenser path. The thermal energy of steam, which accompanies noncondensables, is thus preserved in the cycle as well.

Fig 14F applies teachings to repair a damaged feedwater heater, in lieu of total replacement, as well as enhance cycle thermal efficiency; as follows : a) Full flow bleed stream 4 is conducted to a feedwater heater 99, via an external heat exchanger 104. This is to use bleed stream superheat thermal energy in a reversible manner. Feedwater stream 10 is modulated via a control valve 112.

Stream 12 is reintroduced into the cycle at a suitable point, based upon teachings. The existing integral desuperheat ing zone of the feedwater heater is "neutralized," using a jumper 30.

This is necessary, since the velocity through this zone is extremely high, and is likely to damage the tubes through erosion, if permitted to maintain the high velocity. b) An external condensing heat exchanger 120 is added, with bleed stream conducted via stream 31, and drains via stream 32 to the "parent" heater 199. Feedwater stream follows path 20/21. Line 32 is used for BOTH the bleed stream as well as liquid drains, as an alternate. c) An external drain cooling heat exchanger 140, with a diverted feedwater stream 40/41, via a diverter ejector 141 is shown. Existing drain cooling zone 97 is "neutralized" via the use of a jumper pipe 55.

An external tank 150, and a new water level 60 is shown. A level control valve 152 will maintain the level as before, except that the new level is now at 60.

Fig 14G shows very high pressure, and temperature boiler drum being replaced by a more manageable pressure component. Cycle is shown by node points 1, 2, 3, ..19. The drum is replaced by headers 12, and 7, and intermediate reservoirs 8, 9, 10, ..11. The "smaller" pressure components will have thinner parts. The concept can be applied to cycles with an above critical throttle pressure in stream 15. Additionally, an innovative ejector 104, "driven" by the power of feedwater pump 203 is shown. Induced fluid stream comes through a downcomer 13, and up via heat transfer surface 105. Motivating fluid stream for ejector 104 is feedwater stream 4, providing a passive arrangement, in lieu of a conventional boiler recirculat ion system.

Fig 14H shows deletion of deaerator heater storage tank. Cycle is shown by node points 1, 2, ....10. Stream 25 is bleed stream, and a condensate control valve 106 supplies condensate to the deaerator heater 108, via spray lines 107, trays 125, and water level 27. A hot well 1 provides reservoir, for BOTH the condensate pump 302, as well as, feedwater pump(s) 308, and 309. Deaerator heater 108 is designed to be at a level, suitable to operate a vertical booster pump 308. Pumps are "tied together" electronically, via controls, using a controller 20. The feedwater pump 309, or the booster pump 308 will not run, unless condensate pump 302 is running, thus alleviating the need for a separate water reservoir.

Fig 141 shows thermal energy storage during low load for use for peaking power, using Dowtherm or other suitable fluid. The cycle is shown by node points 1, 2, ....19. The bleed streams are 20, ..26. The add on system follows path 60, 61, ..70, 71 during thermal energy storage cycle. The bleed streams 30, ..36 are from the main cycle, and drains 40, ..46 are cascaded to the corresponding heaters. For peak load, streams 85/86, and 87/88, modulated by valves 186/188, to impose heat transfer reversibility in heat exchangers 180/181 is shown. The heat source, Dowtherm stream follows path 80, ..83, between tanks 71, and 60. Valves 182/169, and a pump 161 are used to effect each cycle, i.e. thermal energy storage, and recovery. The system shown can be gravity based as well, by properly locating various components. The extra peaking power is produced by turbine train 50, ...53, connected across the main turbine train. A condenser 153 communicates with the main condenser by gravity, if so chosen.

Fig 14J shows the application of centrifugal force principle, and elimination of turbulence in a conduit, to enrich air for combustion, and other uses. The objective is separating nitrogen to a large extent, and having oxygen enriched air stream. A blower 101 moves ambient air stream 1/2 through the system. To minimize remixing of the two gases, through turbulent flow, the relative velocity between the "conduit wall" and air, is designed to be a very small, in order to effect LAMINAR flow. The ambient air stream moves through a "spinner" 88 shown by points 20, 21, 22; driven by a motor 122. The "spinner" 88 is a round conduit formed into a "spring like" shape. A controller 120 receives pressure signals 80/81. When RELATIVE velocity between the walls of the "spinner" 88, and the air stream, flowing through it, is "close to zero," the pressure differential between 80, and 81 will be "near zero" as well. This objective is aimed for by the drive 122. The heavier oxygen molecules, molecular weight 32, vs 28 for nitrogen, are then "peeled-off, " as streams 23, and 24 respectively. Flue gas streams 53, 54, 55 is recirculated to temper the very high flame temperature as a result of using enriched air. Blowers 25, 26, 27, and boiler 99, fuel 98 are shown. The system also has heat exchangers 70, 71, 72 for heat exchange with other parts of the cycle based upon teachings.

Another stream 40 is steam at atmospheric pressure. A heat exchanger 140 heats this stream to very high temperature. A stream 41 is then passed over a catalyst bed to break down steam (water), into its constituents, oxygen, and hydrogen, shown by streams 123, and 124 respectively. This separation, using the "spinner" approach, discussed above, is designated by

42. The heat exchangers 60, 61 are to exchange thermal energy based upon teachings. The "spinner" rotating velocity, and the diameter of the "spring like" shape is adjusted to effect the necessary centrifugal differential force on the gas stream constituents to be separated. The teachings can be used for other applications, such as S02, NOX separation in flue gas stream etc.

Fig 15A shows teachings, as applied in repowering a steam cycle with a gas turbine cycle. Steam cycle is shown by node points 1, 2, ..17. Gas turbine cycle is per node points 50, 51, ..53. Gas turbine exhaust stream 53 is cooled in a reversible manner using stream 20 via a condensing heat exchanger coil 120, and by streams 32, and 40 in a duct 300 based upon teachings of Fig 13E. High temperature stream 53 is first cooled by a diverted cold reheat stream 60, via a diverter ejector 161. The stream 61 is recombined with full flow of cold reheat stream 14. The high grade thermal energy of stream 53, 1000 Deg. F, is "piggy backed" via cold reheat, back to the boiler 99. The stream 60 can be replaced, and/or augmented by final feedwater stream as based upon teachings of stream 13/14/140 of Fig 13E.

Fig 15B shows teachings as applied to add an INDIRECTLY heated pull-through cycle to a steam cycle, using combustion air as working fluid. Cycle is shown by node points 1, 2, ..17. Combustion air is first used as working fluid in a pull-through cycle. Combustion air stream 49, at the outlet of the air heater 171, is heated indirectly in a heat exchanger 183, using a diverted flue gas stream 83, diverted from the point 283 of the boiler. The point 283 is branched from the convection pass of the boiler, with minimum quantity of suspended solids. Stream 84 is reintroduced into the cycle. The pull-through cycle follows path 50, 51, 52, 53. Stream 51 is cooled in a duct 300 per teachings, and discussion of Fig 15A. The temperature of streams 84, and 53 will determine the point of reintroduct ion into the cycle, based upon teachings. If

"mixing" of streams 53, and 71 results in a very high temperature at point 81, a heat recovery heat exchanger 181 is added using teachings. In addition, the air heater 171 can be made reversible per teachings. Supplementary firing at points

49, and/or 50 (not shown), is used to optimize the cycle design. The teachings of Fig 15A regarding stream 60 is used here as well .

Fig 15C shows a repowering arrangement using teachings. Cycle is shown by node points 1, 2, ....16. Ambient air stream 20, a pressurized recuperator 121, a post recuperator expansion turbine 322, a compressor 320, and a first turbine 321 are per teachings. An indirect heat transfer surface 122, "drives" the air cycle. Stream 26 is reintroduced into the cycle, with an alternate reintroduct ion point via path 27, when temperature at point 26 is equal to or greater than temperature at point 72. The combustion air stream 26 can be heated per teachings of Fig 13C as well, to optimize the cycle design. An energy mismatch in the air heater 171 can be addressed based upon the teachings of the air heater reversibility.

Fig 16A shows use of high grade thermal energy of reheater drains. Cycle is shown by node points 1, 2, ..14. Liquid drains 16, from a tank 116, having high grade thermal energy, follow path 17, 18, 19, into a top feedwater heater 107. Final feedwater stream 20, is diverted through a heat exchanger 118 via a diverter ejector 108. Temperature at point 9 is elevated, thus improving thermal efficiency. In addition, the level control valve in stream 19 (not shown) is subjected to less severe design conditions. In another arrangement, the drains 17 are first slightly subcooled, using stream 50/51 via a control valve 150. A controller 53 is designed to maintain level in tank 116, by sequentially opening a series of ON/OFF gate valves 152. The diverter ejector 108 will permit reintroduct ion of stream 17 into stream 8. The diverter ejector 108 is necessary because the pressure of stream 17 is LOWER than pressure of stream 8. The stream 17 is thus "pumped" forward by power of pump 206 itself, through the use of the diverter ejector 108. A water turbine in stream 19 (not shown), similar to the turbine 153 of Fig 14B is used to convert pressure energy to propulsive power. Fig 16B arrangement pertains to increasing electric output for higher circulating water temperature for summer operation.

Cycle is shown by node points 1, 2, ..14. Circulating water for condenser cooling is shown by node points 60, 61, 62, 63, 64, and a pump 260. When the circulating water temperature is higher, the back pressure in the condenser will go up, which in turn will not permit a nuclear power plant reactor to be run at its licensed thermal rating. A portion of bleed stream 50 is diverted as stream 51, into a series of heat transfer surfaces

55, 56, 57; immersed in stream 62, discharge of circulating water stream. A series of ON/OFF gate valves 152, 153, 154 are for varying the quantity of diverted steam in stream 51. This is to ensure that ONLY necessary, and sufficient steam flow via stream 51, is diverted around the last stages of the low pressure turbine, to meet the intended objective; which is to allow the reactor to be run at licensed thermal power.

Controllers 97/98, determine the number of valves 152, 153, ... that will be opened to run the reactor at licensed thermal rating. Liquid drains 58 are conducted to a tank 158, with discharge into the condenser via a loop seal 59. In a variation, a stream 90 is diverted, via a diverter ejector 192, and cooled in a heat exchanger 190, by a cooling stream 95. A modulating valve 191 is used to vary the flow in stream 90. A controller 97 determines the rate of flow in diverted streams

90, and 51, in order to run the reactor at licensed thermal duty. The key is to keep the main steam valves (not shown) in full open position, with an optional signal (not shown), into the controller 97. If the condenser CANNOT handle waste heat load, due to higher circulating water temperature, then HIGHER grade thermal energy is discarded from the cycle, via stream

51, and/or 90, or some combination thereof. Other suitable control signals, such as condenser back pressure can also be input into controllers 97/98 to effect the desired plant alignment, once the waste heat discharge system is upgraded, as shown. Additional control input, 30 from the main steam valve

(not shown), and 31 from condenser back pressure are shown, to be used to optimize the design.

Fig 17A shows the use of innovative ejector for part load operation of a steam cycle. Cycle is shown by node points 1,

2, ..18. Variable resistance is introduced into the cycle, by using an innovative ejector thereby keeping the main steam control valve(s) almost FULLY open. The innovative ejector can be at one or more locations such as 61, 62, 63. Location 60 is between the primary, and secondary superheaters 130, and 131.

This will always ensure a constant design temperature at point

130, inlet to the turbine train. The induced fluid can be cold reheat stream 55, or a higher pressure bleed stream 56. An optional dedicated turbine 350 can be added to provide induced fluid stream 51. A feedwater heater 111 can also be added using bleed stream 52. The innovative ejector can use induced fluid as streams 51, 55, 56 or some combination thereof, to keep valve 160 fully open, with minor final trimming for load control. A positioner 161 provides the signal via a controller

(not shown), per teachings of Fig 4E. Similarly, the innovative ejector, in locations 61/62 uses streams 91/96 as induced fluid from suitable bleed stream. The innovative ejector 61, is located between the primary, and secondary reheaters 114/115 to ensure a constant design temperature, usually 1000 Deg. F, at point 15. If the reheater 114 is not part of the design, the innovative ejector, upstream of reheater 115 will still yield the intended results.

Fig 17B shows a series of ejectors to replace some of the turbines in a turbine train. The condensate/feedwater train is shown by node points 50, 51, ....59, 67, 68. Combustion air 30, fuel 31, and innovative ejectors are shown by 201, 202, and

203. Bleed streams 71, 72, ..78, for feedwater heating, are provided from the ejector train, as well as the turbine train.

It should be pointed out that induced fluid streams 80, 81, and

82 are drawn from hot reheat stream, and can be from cold reheat streams as well, per design optimization. A dedicated steam turbine 364 provides bleed stream 74 as well as cold reheat stream 60. Hot reheat stream 63 is conducted to the turbine train 363/365. Stream 82 is recirculated via an innovative ejector 203. Similarly streams 80/81 are recirculated by innovative ejectors 201/202 respectively. The key is that the innovative ejector does "work" as in a simulated "turbine/compressor" combination in lieu of the turbines. The arrangement shown also results in lesser number of different turbines, thus allowing for lesser spare part inventory. The number of innovative ejectors, and the turbines, or part of the turbine train it replaces, can be varied to optimize the cycle design, based upon teachings. Fig 17C shows the use of innovative ejector as a device to produce a working fluid stream by "combining/mixing" a multitude of fluid streams. An innovative ejector is used to impart kinetic energy to the "water; steam" stream, which in turn is shared with the kinetic energy imparted to the products of combustion. The "water" added is thus not for cooling purpose ONLY. The conventional part of the gas turbine system is 1, 2, 3, 4. In the first part of the discussion, point 4 is at atmospheric pressure. A gravity based system with tanks

120/122, a condensing heat exchanger 105, make up water 20, streams 21/22 to provide preheated water, is shown. A very high pressure pump 223 draws suction via a stream 23, which is heated by waste heat of gas turbine exhaust stream 4, per teachings. A very high temperature, and pressure (steam) stream

25, a fuel stream 62, and the very high temperature, and pressure products of combustion stream 50 are "combined/mixed" in a suitable flow ratio, via an innovative ejector 150. The

"mixing" follows the principle of innovative ejector, per teachings of Figs 4A, 4B, ... The innovative ejector 150 yields working fluid stream 52, suitable for use in the gas turbine

303. The key is to use the benefit of Imparting very high pressure energy to the LIQUID stream 24, and recover it as very high work, i.e. enthalpy drop, in the "GAS (steam)" streams

26/27/28/29. Nozzles 126/127/128/129 are to impart velocity to the streams 26, 27, ...before "mixing," to minimize "mixing" losses. In a similar manner, teachings are applied in following flow path 60/360/61. In this case the pressure at point 4/60 is above atmospheric, i.e. 104 is a pressurized recuperator.

Additionally, an alternate path 70/270/71/72/272 also follows teachings, in which the pressure at points 4, and/or 71 is subatmospheric, i.e. a pull-through cycle concept is applied at the tail end. We can "mix and match" various teachings to optimize the cycle design. We MUST however impart pressure energy to the LIQUID stream 24, and recover it via "GAS" stream, as discussed earlier. A controller 180 is shown to control the temperature in stream 3, by processing temperature input via signal 81, and modulating the flow in stream 24 via a signal 80, and a control valve (not shown) in stream 24.

Fig 17D shows an innovative ejector as a topping cycle, using flue gas under pressure as motivating fluid, and subatmospheric pressure air from a pull-through cycle as induced fluid. Ambient air stream 1, a compressor 301, and a pressurized stream 2, is preheated in a heat exchanger 102.

Heated stream 3 is divided into a stream 4 for combustion at high pressure, and a stream 20 for use in an innovative arrangement for coal transport system. A pulverizer 330 provides coal dust 30, 31 from coal feed 80. The pulverized coal is sent to storage tanks 230/231, which are pressurized intermittently to provide pressurized fuel streams 32/33. A controller 40, compressed air stream 20, and control valves

121/122, opening alternately; in conjunction with control valves 130/131 provide a continuous feed via a line 34. Several tanks, in addition to tanks 230/231 are used to compensate for lag time, in switching from the atmospheric pressure to pressurized cycle, in the coal feed operation. A burner 103 provides products of combustion 5 as motivating fluid for an innovative ejector 305. The ejector has a "honey comb" sacrificial surface 405 to handle severe erosion. Stream 6 is designed to be at atmospheric pressure, and below fusion temperature for ash. Boiler 99 is designed in a conventional manner. A pull-through cycle draws ambient air stream 50. A blower 350 moves working fluid stream 51 through the boiler 99.

A gas turbine 352, an exhaust stream 53, and a heat recovery heat exchanger 102 are shown. Stream 54 "drives" a once through cycle 62, via a heat exchanger 154. Stream 55, at a relatively low temperature, is divided into a stream 60, to be recompressed via innovative ejector 305, and a stream 56 to be recompressed via a compressor 356. Stream 57, at a relatively low temperature, "drives" a once through cycle 61, using low boiling point working fluid, in a heat exchanger 157. The heat exchanger 157, and compressor 356 can be located to suit, relative to each other, based upon optimization. The key is to have the products of combustion temperature at stream 5 of the order of 3000 Deg. F. This stream, at suitable pressure, including atmospheric pressure, in turn is used in an innovative ejector to do part of the "work" of the compression stroke of a pull-through cycle.

Fig 17E shows teachings as applied to address smaller rate of throttle flow in a bottoming cycle for a gas turbine based combined cycle system. A gas turbine system, with ambient air

50, a pressurized recuperator 154, and a post recuperator expansion turbine 352 is per previous teachings. A very high pressure, and temperature stream 5 is motivating fluid for an innovative ejector 106, with a discharge stream 7 at above critical pressure. Pressure in stream 8 is further reduced by an innovative ejector 108 to deliver the required design pressure in stream 9, for a turbine train 310/311/312. Stream

22 provides regeneration thermal energy for the gas turbine cycle, in a heat exchanger 122. Stream 24 provides reheat thermal energy for the low pressure steam cycle, in a heat exchanger 124. Similarly stream 20 is used for heating stream 3 in a heat exchanger 120. Liquid drains are collected in a tank

40 to form the rest of the cycle. A start up line 60, with a restriction orifice 61, and an ON/OFF valve 62 is shown. Thus a relatively low flow stream 5, because of very high pressure, and temperature, is transformed into a higher flow stream 10.

A recap is presented to indicate that the variations, based upon teachings, are included, without violating the spirit of the invention. The working fluids are interchangeable, i.e. water, ammonia, carbon dioxide, or any other fluid, as working fluids can be interchanged based upon teachings. Heat capacity of the fluids, in the heat exchange process is equated, except INTENTIONAL departure, based upon discussion of Fig 131, and ITS TEACHINGS. THUS in some cases, when the thermal energy of a particular stream is "discarded," an optimization exercise will offer the best cycle con iguration, and design parameters.

The heat transfer reversibilit is imposed via sensible heat transfer only. This "tool" can be applied for heat transfer reversibility, both for below critical and ac streams, as long as heat transfer involves SENSIBLE heat ONLY.

Additionally, reversibility in mixing is also imposed, when the temperature for the streams to be mixed, can be equalled, by heating, before mixing, to effect reversibility in the mixing process .

Various temperature and pressure values used in the discussion are not the design values, and are used as aid to understanding the invention. These values are not to be construed to serve any other function.

The invention has been illustrated with respect to specific embodiments, it is to be understood that numerous variations, changes, and modifications can be made thereto, without violating the intent and the spirit of the disclosure; and includes their equivalents.

Claims

Claims: I claim: (Please cancel Claims 1-3, and add Claims 4-9)

1. A power cycle in which HEAT TRANSFER REVERSIBILITY is used to the maximum extent, by using, and recognizing the sensible heat, of both liquid, and vapor. This is achieved, wherever possible, by suitably modulating the appropriate stream in the heat exchange process. When appropriate, the latent heat, is removed, as the heat source consideration, by designing the parts of the system applicable, to be above critical pressure, the latent heat being zero in this application of feedstream heating. The resulting single stage feedstream heating is then the key component in the building blocks of an ideal cycle.

2. A power cycle, in which there is no phase change, such as a gas turbine cycle, wherein, the expansion in the turbine is conducted to the subatmospheric pressure regime. The gases are then suitably cooled, and then recompressed to be discharged into the atmosphere, yielding net positive work. Additionally, a cycle in which, the gas cycle arrangement involves multiple reheats at suitable pressures .to maximize the thermal efficiency, and to use up all the oxygen in the air stream. In order to yield a cooler gas turbine exhaust, a gas turbine cycle in which, a larger quantity of heat energy is recirculated by incorporating a recuperator at a suitable place in the cycle, in which an expander is introduced downstream of the said recuperator. The proposed features, then become the basic building blocks of a more complex/composite cycle .

3. A power cycle in which single stage feedstream heating, and expansion below the atmospheric pressure, in a single phase, gas turbine cycle, are the basic building blocks of a more composite cycle, in direct as well as indirect heating of working fluid(s). A power cycle applicable for mobile power plant, in which the building blocks are suitably applied, and on board compressed air is shown, to eliminate the negative work of compression, thereby freeing more net work attributable to premium fuel.

4. A power generation system having a boiler, for combustion of fuels to produce steam at very high pressure, substantially above critical pressure; a connected steam turbine train to expand the above critical pressure steam to a pressure, which is still at above critical pressure at the outlet of the first steam turbine; conducting the said above critical pressure stream to a plurality of heat exchangers, disposed in parallel, to heat feedstream, combustion air, cold reheat, in a manner, resulting in equal heat capacity for the two streams, in said plurality of heat exchangers, having steam and liquid interface, based upon overall heat transfer coefficient, and heat capacities of the said fluids; equal heat capacity heat exchangers heating feedwater, combustion air, cold reheat, having liquid drains combined, for introduction into feedstream stream; having remaining steam stream from the outlet of the said first steam turbine conducted to rest of turbine train, with reheaters connected thereto, and a condenser to produce liquid feedstream.

5. The power generation system of Claim 4 having above critical stream from outlet of first steam turbine; having said above critical steam used for heating of working fluid stream, of a second power generation system, having design conditions substantially at above critical pressure, thus resulting in a combined cycle configuration; having heat exchange conducted in a manner resulting in equal heat capacities for said above critical pressure heating stream and said working fluid stream of the said second cycle; having working fluid stream of the said second power generation system at pressure below critical pressure, and having said feedstream heated by the said above critical pressure stream, from the said first power generation cycle, such that said below critical pressure stream is heated to remain in liquid phase.

6. A power generation system comprising of a compressor, a combustor to produce hot gases, a first gas turbine, called truncated gas turbine, to expand the hot gases to a pressure substantially above atmospheric pressure, a recuperator under pressure, called pressurized recuperator, to exchange thermal energy between the compressed air, from the outlet of the said compressor, and the hot gases leaving the said truncated gas turbine, a second gas turbine to expand the hot gases, leaving the said pressurized recuperator, to a pressure equal to the atmospheric pressure; the said gas turbines having a plurality of combustors disposed between the said turbines.

7. The power generation system of Claim 6 in which the said first and second gas turbines are part of a closed system, allowing the said second gas turbine to discharge the exhaust to a pressure which is below atmospheric pressure; the said gas turbines having a plurality of combustors disposed between the said turbines; the said recuperator of the gas turbine cycle having a heat transfer surface having above critical pressure stream as the heat sink, producing an above critical pressure gas stream; the said above critical pressure stream expanded in a first turbine to a pressure still at pressure which is above critical pressure; the said above critical pressure stream heating compressed air from the outlet of a compressor, of the said gas turbine cycle, in manner that equates heat capacities of the said streams; the said power generation system having an intermediate recuperator, before the said second gas turbine, used to regenerate thermal energy in heating of the said compressed air; the said power generation system having a plurality of gas turbines with a plurality of intermediate reheats, and plurality of intermediate recuperators, with a final gas turbine at the outlet of the last of the said intermediate recuperators; a power generation system having a plurality of fuel additions, as in a reheat gas turbine cycle, the heat capacity of the streams, the said compressed air, and the said products of combustion, in the intermediate recuperator equalled, by diverting a portion of the said products of combustion, with high grade thermal energy, entering the said intermediate recuperator, for use in a heat recovery system.

8. A power generation system, having working fluid stream at substantially high pressure and temperature, having a pressure increasing device, a turbine, said turbine having a plurality of outlets to have the ability to draw partially expanded working fluid stream, having a load connected thereto; the said high pressure and temperature stream having a plurality of parallel paths, each of the said paths having a nozzle, thus imparting high velocity to the said parallel streams; the said partially expanded stream also having a plurality of parallel paths, each of the said paths having a nozzle, thus imparting high velocity to the said streams; the said streams combining in a common conduit, through a plurality of sequentially opening valves; the said valves being controlled by a controller to satisfy a predetermined criteria; the said criteria controlling the said controller.

9. A power generation system having a boiler, for combustion of fuels to produce steam at subcritical pressure, a connected steam turbine train, and reheaters, to expand the subcritical pressure steam into a condenser, to produce the liquid feedstream, and a plurality of bleed streams for regenerative heating; the said power generation system having combustion air stream, condensate stream, feedwater stream, heated successively with the said plurality of regenerative bleed streams, using latent beat; the said power generation system having liquid drains from the said heating of said combustion air stream, said condensate stream, said feedwater stream, conducted to a vertical heat exchanger; the said beat exchangers heating said condensate stream, said feedwater stream; the said liquid stream from the said combustion air heating, conducted to the said heat exchangers; the said power generation system having a flue gas stream, leaving the said boiler, cooled successively using a diverted and modulated stream of said feedwater stream, and said condensate stream, in a manner, that will equal the heat capacities, of the said flue gas stream, and the said diverted feedwater, and said condensate streams; the said flue gas stream being cooled further by being passed over a plurality of tubes; the said plurality of tubes having the said condensate stream, passing thru, at atmospheric pressure, via gravity flow, between overhead tanks; the said power generation system having the superheat of said bleed streams, transferred to a diverted flow of said combustion air stream, said condensate stream, said feedwater stream, in a manner, that will equal the heat capacities of the said streams in the said heat exchange process; the said power generation system having a blow down stream from the said boiler, cooled successively, by diverting said condensate, and said feedwater stream, in a manner, that will equal the heat capacities of said streams in the heat exchange process .