JPH06221115A - Heat recovery type power generation device - Google Patents

Abstract

PURPOSE:To provide a heat recovery type power generation device which recovers heat by utilizing low temperature exhaust heat, and thereby efficiently extracts power. CONSTITUTION:An absorption refrigerating cycle 10 is composed by connecting in order a steam absorber 14 which makes high-density absorbent solvent steam or moisture and generates low density absorbent solvent, a pump means 15 which extracts the absorbent solvent, a steam separator 17 which heats the absorbent solvent press-fed by the pump means and separates steam from the high-density solvent, and a condenser 18 which cools and condenses the separated steam, to each other. A steam expansion cycle 11 is assembled in the absorption refrigerating cycle 10, which steam expansion cycle 11 is provided with a steam generator performing water supply and heating by utiizing low temperature discharge heat and a power extracting steam turbine 33 driven by the steam from the steam generator 17. Exhaust from the steam turbine is guided into the steam absorber, while high-density absorbent solvent extracted from the bottom of the steam separator is guided to the steam absorber 14 through a pressure reducing device 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat recovery power generator utilizing low temperature exhaust heat from a steel plant or a food factory, and particularly, an absorption refrigeration cycle utilizing low temperature exhaust heat in combination with a vapor expansion cycle. The present invention relates to a heat recovery power generator with an improved steam Rankine cycle.

[0002]

2. Description of the Related Art A steam Rankine cycle is one of the heat recovery plants that utilize waste heat. In a normal steam Rankine cycle, low-temperature low-pressure steam from which the heat drop energy has been extracted is guided to a condenser and condensed there, after which the condensed condensate is boosted by a pump to generate high-temperature high-pressure steam from a boiler or the like. The high-temperature and high-pressure steam that is sent to the generator is circulated to a power generator such as a steam turbine to perform work, but in this steam Rankine cycle, the low-temperature formed by the condenser that extracts the latent heat of the steam is formed. The pressure level limits the energy extraction.

Therefore, in the steam Rankine cycle, the cooling water temperature of the condenser is one of the major factors that determine the thermal efficiency and capacity of the plant. Due to this factor,
Even if there is low temperature exhaust heat of about 100 ° C or more from a steel mill or food factory, the heat drop between this low temperature exhaust heat and the atmospheric temperature on the low temperature low pressure side is not sufficient, and the plant output cannot be improved. , No attempt has been made to recover the power of the low temperature exhaust heat.

However, due to the recent tightness of the energy environment and the emergence of global environmental problems associated with the burning of fossil fuels, there has been an attempt to review and utilize the thermal energy in the low temperature region which has not been used conventionally. In the conventional steam Rankine cycle, the cooling source temperature on the low temperature side is determined from the atmospheric temperature or the seawater temperature, and is about 300K. The enthalpy of saturated steam at this temperature is 2550 KJ /
It is kg.

On the other hand, the condensation temperature of water vapor is 280K.
If it can be reduced to, since the enthalpy at this temperature is 2514 KJ / kg, the energy corresponding to the difference can be extracted extra. Initial temperature is 370
If K, the enthalpy at this temperature is 267
Since it is 0 KJ / kg and energy is extracted from 2670 KJ / kg, the cycle output of about 30% can be improved.

In the steam Rankine cycle plant, improving the conditions on the low temperature side (cooling source temperature side) in this way leads to an improvement in the cycle plant output. This is especially important in plants that use low-temperature exhaust heat as a driving heat source.

[0007]

In the conventional plant technology using the steam Rankine cycle, a heat-driven absorption refrigerating machine is used in order to lower the temperature on the low temperature side to the atmospheric temperature or lower by utilizing exhaust heat. I have to do it. All heat transfer in a conventional plant using an absorption chiller is carried out via a heat exchanger, so the temperature difference of the absorption chiller is affected by the required temperature difference of the heat exchanger. It disappeared and there was a problem in practical application.

The present invention has been made in consideration of the above-mentioned circumstances, and heat is recovered by utilizing low-temperature exhaust heat having a relatively low temperature, and power can be efficiently taken out by energy recycling. An object is to provide a power generation device.

Another object of the present invention is to improve the steam Rankine cycle to efficiently operate the exhaust heat at a relatively low temperature to improve the energy recovery efficiency and to improve the low temperature low pressure side steam condition of the steam Rankine cycle. It is to provide a heat recovery power generation device that can be achieved.

Another object of the present invention is to replace a part of electric power or turbine driven steam obtained by burning fossil fuel with an energy cycle utilizing exhaust heat at a relatively low temperature,
It is an object of the present invention to provide a heat recovery power generation device capable of improving final energy efficiency and protecting the global environment.

Another object of the present invention is to provide a heat recovery power generation device which can utilize the power recovered by heat recovery of exhaust heat at a relatively low temperature for power generation, heat pump drive and compressor drive. There is.

[0012]

In order to solve the above-mentioned problems, the heat recovery power generation device according to the present invention has the following features:
As described above, a vapor absorber that absorbs water vapor or water in a high-concentration absorbent solution to generate a low-concentration absorbent aqueous solution, pump means for taking out this absorbent aqueous solution and pumping it up, and this pump Absorption refrigeration cycle by sequentially connecting a vapor separator that heats the aqueous absorbent solution pumped by the means to separate it into water vapor and a high-concentration absorbent solution, and a condenser that cools and condenses the separated water vapor. On the other hand, in this absorption refrigeration cycle,
A turbine that worked in the steam turbine by combining a steam expansion cycle that includes a steam generator that uses low-temperature exhaust heat to heat feed water and a steam turbine for extracting power that is driven by steam from the steam generator. The exhaust gas is guided to the vapor absorber, and the high-concentration absorbent solution taken out from the bottom of the water vapor separator is guided to the vapor absorber via a decompression device.

In order to solve the above problems, the heat recovery power generation device according to the present invention is condensed by the condenser as described in claim 2 in addition to the contents described in claim 1. A step-up pump means for taking out the condensed water and pumping it up is provided, and the condensed water pumped up by the step-up pump means is guided to the steam generator. Further, as described in claim 3, the steam absorber is cooled. A cooling device having a pipe is provided, and a high-concentration absorbent solution is supplied to the steam absorber from the upper part, while turbine exhaust is supplied from the lower part, and further, as described in claim 4, The separator is provided with a heating device for heating the low-concentration aqueous solution of the absorbent, and the low-concentration aqueous solution of the absorbent is allowed to flow down into the heating device in a heat-exchangeable manner. A cooler is installed in the pipe that guides the high-concentration absorbent solution taken out from the bottom of the separator to the vapor absorber, and the cooler is provided with the high-concentration absorbent solution from the vapor absorber. It is formed by a counter-flow heat exchanger capable of exchanging heat with an aqueous solution, or, as described in claim 6, the steam separator has a pressure inside the steam generator lower than the pressure inside the steam generator during operation. The pressure is set to be higher than that of the absorber.

Further, in order to solve the above-mentioned problems, the heat recovery power generation device according to the present invention is capable of exchanging heat with low temperature exhaust heat in the steam generator and the steam separator. Different heating devices are respectively provided, and the heating device of the steam generator and the heating device of the steam separator are connected in series to form a multi-stage structure. Further, as described in claim 8, the steam turbine has a multi-stage structure. The turbine extraction air reheat system is taken out from the middle stage of the steam turbine while the turbine extraction air reheat system is constructed. The downstream side is connected to the downstream paragraph of the steam turbine.

[0015]

This heat recovery power generator uses the exhaust heat of a relatively low temperature in the steam generator to heat the feed water to generate steam, which is guided to the steam turbine to drive the steam turbine. Then, while the power is taken out, the back side of the steam turbine is connected to a steam absorber, and the steam of the turbine exhaust is absorbed by the steam or an absorbent solution that absorbs water in the steam absorber. Since it is possible to lower the pressure on the side and to extract steam energy to the low pressure and low temperature level in the steam turbine,
Even if heat recovery is performed by using low temperature exhaust heat having a relatively low temperature, power can be efficiently taken out by energy recycling.

In this heat recovery power generation device, the steam Rankine cycle is improved so that heat can be efficiently recovered from exhaust heat of a relatively low temperature.
Since the steam can be effectively used up to the low pressure level, the energy recovery efficiency can be improved and the steam condition on the low temperature / low pressure side of the steam Rankine cycle can be improved.

Further, in this heat recovery power generator, the power obtained by recovering the heat of the relatively low temperature exhaust heat can be used for power generation, compressor drive and heat pump drive. A part of the electric power or turbine driving steam obtained by burning the fuel can be replaced and replaced, the final energy efficiency can be improved, and the global environment can be protected.

Further, in this heat recovery power generation device, an absorption refrigeration cycle is constituted by the vapor absorber, pump means, vapor separator and decompression means, and the absorbent solution for absorbing water vapor or water is absorbed in the absorption refrigeration cycle. Circulate,
Even if the absorbent solution absorbs water vapor or water in the vapor absorber to cause a concentration decrease, this low-concentration aqueous absorbent solution separates the water vapor by heating in the vapor separator to increase the concentration. This high-concentration absorbent solution is depressurized and re-guided to the steam absorber, so that the absorption capacity of water vapor absorbed by the absorbent solution in the steam absorber is maintained effectively and continuously. can do. This water vapor absorption capacity can be further improved by cooling the inside of the vapor absorber.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the heat recovery power generator according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing the overall structure of a heat recovery power generator according to the present invention. This heat recovery power generation device performs heat recovery by utilizing low temperature exhaust heat emitted from various plants such as steel mills and food factories and having a relatively low temperature, for example, about 100 ° C. or higher, and power generation and The power for driving the heat pump and the compressor is taken out. The heat recovery power generator is a first-type absorption refrigeration cycle 10 applied to an absorption refrigerator or the like.
The steam Rankine cycle 12 applied to a power plant or the like as a power take-out device is improved by combining the steam expansion cycle 11 utilizing low temperature exhaust heat.

The first-type absorption refrigeration cycle 10 includes a vapor absorber 14 as a low pressure generating means and a low pressure tank equipped with a cooling device 13, and a high concentration absorbent such as lithium bromide (LiBr) in the vapor absorber 14. A pressurizing pump 15 as pump means for taking out and pumping up a low-concentration absorbent aqueous solution in which water vapor or water is absorbed in the solution;
A vapor separator 17 equipped with a heating device 16 that utilizes low temperature exhaust heat to heat the pressurized low-concentration aqueous solution of the absorbent; and a condenser 18 that cools and condenses the water vapor separated by the vapor separator 17. A decompression valve (expansion valve) 19 as a decompression device for taking out and decompressing the absorbent solution that has been separated by the vapor separator 17 and has a high concentration, and a high-concentration absorption reduced by the decompression valve 19. It is composed of a cooler 20 for cooling the agent solution as needed. LiBr is mainly used as an absorbent, and H ₂ O- is used to prevent crystallization.
_{LiBr-LiCl, H 2 O-} LiBr-LiSCN,
_{H 2 O-LiBr-ZnCl 2} , H 2 O-LiBr-Z
There are combinations such as nBr ₂ .

The cooler 20 is installed, if necessary, on the downstream side of the pressure reducing valve 19 of the pipe 21 for guiding the high-concentration absorbent solution collected at the bottom of the vapor separator 17 to the vapor absorber 14. The cooler 20 is formed of a counterflow heat exchanger, and is provided so as to be able to exchange heat with the low-concentration low-temperature absorbent aqueous solution from the vapor absorber 14.

On the other hand, the condenser 18 is provided with a cooling device 24 for cooling the water vapor separated by the vapor separator 17, and the condensed water cooled and condensed by the cooling device 24 is taken out by a step-up pump 25 as pump means. Is pressurized and sent to the steam generator 26 of the steam expansion cycle 11 as feed water. From the downstream side of the booster pump 25, the drain valve 2
The drain pipe 28 provided with 7 may be branched, and the condensed water may be drained through the drain pipe 28. In this case, water is supplied to the steam generator 26 by a water supply pipe 30 having a water supply valve 29.
Through.

The steam expansion cycle 11 includes a steam generator 26 equipped with a heating device 32 for heating the feed water by utilizing low temperature exhaust heat, and a steam turbine for power extraction in which the steam generated by the steam generator 26 is guided. 33 and 33. The steam turbine 33 is connected to a generator, a compressor or the like via a coupling (not shown) and drives the generator or the compressor. When driving the generator,
Electric power is generated by a steam-driven turbine, and this electric power can cover the required electric power for the pumps, cooling towers, etc. in the system, making it possible to provide a power generator with extremely high energy savings. Become.

The steam turbine 33 may be a mixed-flow turbine or an axial-flow turbine, but a condenser is not provided on the back side of the turbine and the steam absorber 14 as a low-pressure tank is used.
Is directly connected to the bottom of. By directing the turbine exhaust in which the steam turbine 33 has been expanded to work by working on the steam absorber 14 and the heat energy has been extracted, the turbine back pressure is not reduced to steam condensation, but is reduced to the steam atmosphere of the absorbent, A sufficient heat drop can be secured. As a result, the thermal energy (enthalpy) of the steam in the steam turbine 33 can be utilized to a considerably low pressure / low temperature level.

In order to efficiently absorb water vapor or water in the steam absorber 14 in which the turbine exhaust is guided, it is necessary to keep the absorbent solution such as a lithium bromide solution at a low temperature. A cooling device 13 is provided at 14. In the cooling device 13, a large number of cooling pipes 13a arranged in the vapor absorber 14 are arranged in parallel,
The cooling water branched from the supply header 35 is supplied into each cooling pipe 13a to cool the inside of the vapor absorber 14, thereby efficiently absorbing the water vapor into the high-concentration absorbent solution.
The cooling water that has cooled the inside of the vapor absorber 14 is collected by the drain header 36 and drained to the outside. The cooling pipes 13a arranged in the vapor absorber 14 may be connected in series, and in this case, the supply header 35 and the drain header 36 are unnecessary.

For example, a lithium bromide solution that absorbs water vapor or water can reduce the water vapor pressure to several Torr (Torr = mmHg) regardless of the temperature of about 30 ° C. This corresponds to a condensing temperature of several degrees Celsius, and the temperature of the cooling fluid is equal to or lower than 0 degrees Celsius.

As described above, if the action of absorbing water vapor by the absorbent solution is used, it is possible to reasonably reduce the pressure to a considerably low pressure at the atmospheric temperature level.

Also, the high-concentration absorbent solution is used for the vapor absorber 1.
Water vapor or water is absorbed in 4 to reduce the concentration of the absorbent solution from, for example, 60 wt% to 55 wt%, and the diluted solution is diluted. At that time, in order to efficiently contact the absorbent solution and the steam of the turbine exhaust in the steam absorber 14 and generate uniform absorption, the turbine exhaust is injected from the lower part (lower part) of the steam absorber 14, The high-concentration absorbent solution is supplied from the upper part (top part) of the vapor absorber 14 through the nozzle 37 to the cooling device 1.
Each cooling pipe 1 of the cooling device 13 is made to flush toward 3
Sequential flow along 3a ensures even absorption of water vapor or water into the absorbent solution.

Cooling pipe 13a provided in the vapor absorber 14
Is not limited to that shown in FIG. 1, and a cooling pipe with heat exchange fins or a plate with holes having cooling pipes may be arranged in a multi-stage structure.

A plurality of heating pipes 16a are arranged in parallel in the heating device 16 arranged in the vapor separator 17 of the first type absorption refrigeration cycle 10, and a low temperature exhaust heat fluid is provided in each heating pipe 16a. While the supply header 40 for supplying the water is connected, a drainage header 41 is provided on the downstream side of each heating pipe 16a.
The fluid collected by the drain header 41 is discharged to the outside. Each heating tube 16a may be connected in series or may have fins.

In the vapor separator 17, the low-concentration aqueous solution of the absorbent is heated by utilizing low temperature exhaust heat to separate the water vapor from the absorbent solution, while the water-separated absorbent solution is moved in the absorbent flowing direction. It is necessary to make it flow down by the action of gravity and gradually increase the concentration. Therefore, it is necessary to spray the low-concentration aqueous solution of the absorbent toward the heating device 16 by the nozzle 43 provided on the upper part of the steam separator 17, while advancing the steam separation action in a low-pressure atmosphere from the steam generator 26.

That is, the operating pressure in the steam separator 17 is higher than the internal pressure of the steam absorber 14, and the steam generator 2
It is necessary to keep the pressure lower than the internal pressure of 6. The steam separator 17 heats the absorbent aqueous solution that has absorbed water vapor and has a low concentration, separates the water vapor to increase its concentration, and sends the separated water vapor to the steam turbine 33 again.
The internal pressure of the steam separator 17 needs to be higher than the steam absorption pressure of the steam absorber 14 and lower than the turbine inlet steam pressure of the steam turbine 33.

Since the vapor absorber 14, the vapor separator 17, and the vapor generator 26 are maintained in the above-mentioned pressure relationship, pump means for pumping up the low-concentration absorbent aqueous solution produced in the vapor absorber 14. 15 and pump means 25 for pumping the condensed water separated and condensed by the steam separator 17 to the steam generator 26 as feed water, respectively. In the steam generator 26, low temperature exhaust heat is used to generate high pressure again. A heating device 32, which is a steam converting means for generating steam, is required.

Further, the steam generator 26 is provided with a superheater (not shown) which superheats the steam generated by the heating device 32, and superheats the steam generated by this superheater to obtain a vapor of higher dryness. Can be Also in this case, it is desirable to use low-temperature exhaust heat for the superheater, in which case the superheater, the heating device 32 of the steam generator 26 and the heating device 16 of the steam separator 17 are sequentially connected in series in this order. To be done.

Next, the operation of the heat recovery power generator will be described.

In this heat recovery power generator, about 100 ° C.
An example will be described in which a low temperature exhaust heat is used and a lithium bromide solution is used as the absorbent solution.

A low temperature exhaust heat of about 100 ° C. is used for the heating device 32 provided in the steam generator 26 of the heat recovery power generating device, and the steam pressure in the steam generator 26 is about 100 ° C. by utilizing this low temperature exhaust heat. High pressure / temperature steam is generated at 80 kPa (saturated steam temperature of about 95 ° C).

The steam generated by the steam generator 26 is guided to the steam turbine 33, where it works and expands to become low-temperature low-pressure steam, which serves as low-pressure generating means (low-pressure tank). Guided to the absorber 14. In the steam turbine 33, the energy of working steam is converted into motive power and taken out, and a generator and a compressor (both not shown)
Etc. are driven.

In this heat recovery power generator, the turbine back side of the steam turbine 33 is connected to the steam absorber 14 as a low pressure generating means, and the turbine back pressure is absorbed by the absorbent solution instead of the conventional condenser. It has been lowered to use.

The low-pressure steam flowing out from the steam turbine 33 is absorbed in the steam absorber 14 by a lithium bromide solution which is a high-concentration absorbent solution of, for example, about 60 wt%. The lithium bromide solution flows down from the upper part of the vapor absorber 14 while passing through each cooling pipe 13a.
Cooling water of, for example, about 30 ° C. is supplied into each of the cooling pipes 13 a via the supply header 35 to cool the lithium bromide solution which is the absorbent solution to about 35 ° C.

As a result, the pressure in the vapor absorber 14 is 1 k.
It decreases to about Pa. Therefore, in the steam turbine 33, the steam condition at the turbine inlet (80 kPa, 2665 K
J / kg) to the exit state (1 kPa, 2085 KJ /
It is theoretically possible to extract steam energy up to kg). Turbine efficiency is 1 in the actual heat recovery power generator
If not 65% but, for example, about 65%, the final energy extraction amount in the steam turbine 33 will be 390 KJ / kg.

By the way, the water vapor absorption action in the vapor absorber 14 decreases or disappears when the concentration of the aqueous absorbent solution decreases due to the absorption of water vapor, so that in the heat recovery power generator, the vapor separator 17 is used. The steam is separated from the aqueous solution of the absorbent having a low concentration by the heating device 16 that uses low temperature exhaust heat to recover the concentration of the absorbent solution to increase the concentration.

The absorbent solution that absorbs water vapor circulates between the vapor absorber 14 and the vapor separator 17 so that the vapor absorbing and separating actions can be continuously performed.

On the other hand, the aqueous solution of the absorbent (lithium bromide aqueous solution) which has absorbed the water vapor (water) in the vapor absorber 14 is reduced in concentration from 60 wt% to 55 wt%, diluted and taken out from the vapor absorber 14. The pressure is increased from 1 kPa to about 1 by the pressurizing pump 15 as pump means.
It can be raised to about 0 kPa. The pressure-increased low-concentration aqueous solution of the absorbent is raised in temperature from about 35 ° C. to about 80 ° C. by the heat exchanger 20 and is sent to the steam separator 17 to flow into the steam separator 17.

In the steam separator 17, low temperature exhaust heat of about 100 ° C. is heated by the circulating heating device 16 to separate water vapor from the aqueous absorbent solution. The concentration of the lithium bromide solution, which is the absorbent aqueous solution, gradually increases due to the separation of the water vapor from the absorbent aqueous solution, and finally the concentration thereof is increased to, for example, 60 wt% and then discharged from the lower part of the vapor separator 17.

The high-concentration absorbent solution (lithium bromide solution) discharged from the vapor separator 17 is decompressed by the decompression valve 19 and then guided to the heat exchanger 20 as a cooling device, where the low-concentration absorbent solution is introduced. About 45 by exchanging heat with the aqueous solution of absorbent
The temperature is lowered to about 0 ° C. and flashed from the upper part of the vapor absorber 14 into the vapor absorber 14.

On the other hand, the water vapor separated by the vapor separator 17 is guided to the condenser 18 by a pipe and is cooled by the cooling device 24 in the condenser 18 to become condensed water. This condensed water is taken out from the lower part of the condenser 18 and is heated to about 80 k by a booster pump 25 as a pump means.
The pressure is increased to Pa or higher and sent to the steam generator 26.
When the supply of water to be supplied to the steam generator 26 is ensured, the condensed water whose pressure is increased by the pressure increasing pump 25 may be discharged to the outside.

The feed water supplied to the steam generator 26 is heated by a heating device 32 utilizing low temperature waste heat, and is heated to about 80 k
It becomes water vapor of Pa. It is preferable that the generated steam is superheated by a superheater (not shown), and is guided to the steam turbine 33 after being superheated to improve turbine efficiency.

FIG. 2 is a steam enthalpy-entropy diagram showing the expansion process of water vapor in the heat recovery power generation apparatus. In the figure, reference character a indicates ideal adiabatic expansion in the steam turbine 33 and reference character b. Shows the actual expansion process in the steam turbine 33. According to FIG. 2, the steam turbine 33
It can be seen that the steam in the turbine blade of No. 2 starts to expand from about 80 kPa and finally becomes low pressure steam of 1 kPa with a wetness of about 10% (dryness of 90%) and flows out to the steam absorber 14.

On the other hand, the water-steam loop of the steam expansion cycle 11 constituting the power generation cycle is slightly complicated as compared with the first-type absorption refrigeration cycle 10 which is a steam absorbent loop. The steam separated by the steam separator 17 of the absorption refrigeration cycle 10 is once condensed by the condenser 18 to be condensed water, which is then boosted to about 80 kPa by the booster pump 25 and sent to the steam generator 26 with high pressure. , Here it is steaming again. This requires that the pressure for separating water vapor from the aqueous absorbent solution be lower than the pressure of the steam generator 26.

Further, the steam once absorbed in the absorbent aqueous solution is heated in the steam separator 17 at a low pressure using low temperature exhaust heat to extract steam, and the extracted steam is condensed into water. By returning the pressure and raising the pressure of this condensed water by the pressure raising pump 25, it is possible to take out higher pressure steam even if the exhaust heat having the same temperature is used.

FIG. 3 shows the state change c when a lithium bromide solution is used as an absorbent solution that absorbs water vapor or water, on a Duhring diagram.
d shows the crystal line of a lithium bromide solution.

Vapor absorber 14 of this heat recovery power generator
The cooling water used in the cooling devices 13 and 24 of the condenser 18 is manufactured in a cooling water manufacturing device (not shown), and is also used in the heating devices 16 and 32 of the steam separator 17 and the steam generator 26. The low-temperature waste heat that is exhausted is waste heat steam or warm waste water, and the low-temperature waste heat of about 100 ° C. discharged from a steel plant or the like is discharged from another plant, for example, about 3
Various uses can be made up to low temperature exhaust heat exceeding 00 ° C.

In this heat recovery power generation device, even if the exhaust heat has a relatively low temperature, the heat energy of the low temperature exhaust heat is converted into the enthalpy of high-pressure steam, and this heat energy is utilized to the state of extremely low enthalpy. Since the enthalpy difference is taken out as power, the power extraction efficiency can be improved.

Unlike the conventional steam Rankine cycle configuration in which low-temperature cooling water is produced by an absorption refrigerator and is used as cooling water for a condenser to increase the extraction enthalpy, this heat recovery is performed. In the improved steam Rankine cycle used in a power generator, the cycle final pressure is reduced to the pressure obtained by the steam absorbing action of the steam absorbent solution.

As a result, the steam Rankine cycle applied to the heat recovery power generator does not require a large condenser, and the steam absorber 14 in place of the condenser transfers heat via the heat transfer surface of each cooling pipe. Since the steam is absorbed directly by the direct contact, the size and size can be reduced, while the pressure inside the steam absorber 14 can be reduced.
It makes it possible to greatly improve plant efficiency. This indicates that the heat recovery power generator can be applied to power plants where the use of cooling water is restricted within the continent.

Further, since the heat recovery power generator uses the low temperature exhaust heat of the temperature only in the improved steam Rankine cycle 12, the steam absorber 14 and the absorbed steam by the aqueous lithium bromide solution are heated and separated. The steam separator 17 and the steam generator 26 that generates water vapor by heating the water by the low temperature exhaust heat have different pressures.
The tanks 14, 17, and 26 are connected to each other by a lithium bromide aqueous solution and condensed water piping, and a pump means is installed in the middle of the tank to utilize the pressurizing action of the pump. On the contrary, a pressure reducing device such as a valve or a steam turbine 33 is installed in a portion of the steam Rankine cycle 12 from the high pressure portion to the low pressure portion to generate a pressure reducing action.

In the vapor absorber 14 and the vapor separator 17, the lithium bromide concentration decreases or increases due to water vapor absorption and water vapor generation, respectively, but in order to achieve this process with high efficiency, the vapor absorber 14 is provided with a cooling device 13. In addition to the installation, the cooling device 13 removes heat generated when absorbing water vapor, and in order to obtain the effect of sequentially forming a concentration decrease of the aqueous solution, a high-concentration aqueous solution is dropped from above through the cooling device 13. .

Similarly, in the steam separator 17, the concentration of the aqueous solution gradually increases due to heating, and the concentrated aqueous solution does not mix with the aqueous solution of low concentration. The aqueous solution is flowed down or dropped from above through the heating device 16.

FIG. 4 shows another embodiment of the heat recovery power generation device according to the present invention.

The heat recovery power generator shown in this embodiment shows the steam expansion cycle 11A side.
The configuration on the seed absorption refrigeration cycle side does not differ from that of the heat recovery power generation device shown in FIG. The heat recovery power generation device shown in FIG. 4 is suitable when the low temperature exhaust heat used is relatively high temperature.

In this heat recovery power generation device, the steam turbine 33A used in the steam expansion cycle has a multi-stage blade structure (multi-stage paragraph structure), and the turbine extraction reheat system 50 is taken out from the middle stage of the steam turbine 33A.
The turbine extraction air reheating system 50 has a reheater 51 in the middle thereof, and the downstream side of the reheater 51 is connected to the downstream paragraph of the steam turbine 33A.

The reheater 51 used in the turbine extraction air reheat system 50 also serves as a cooler for the condenser 18, and the steam separated by the steam separator 17 in the reheater 51 (for example, 60 mmHg, 42 to 45). (° C) is heat-exchanged, and this steam is cooled and condensed to reheat the turbine extraction air. The turbine bleed air absorbs the latent heat of steam to improve system efficiency.

[0065]

As described above, in the heat recovery power generation device according to the present invention, the feed water is heated by using the exhaust heat having a relatively low temperature in the steam generator to generate steam, This steam is guided to the steam turbine to drive the steam turbine, and power is taken out, while the back side of the steam turbine is connected to a steam absorber, and the turbine is used as an absorbent solution that absorbs steam or water in the steam absorber. Since the steam of the exhaust gas is absorbed, the turbine back side of the steam turbine can be made even lower in pressure, and the steam energy can be taken out to the low pressure and low temperature level in the steam turbine. The heat can be recovered by utilizing it, and the power can be efficiently taken out by energy recycling.

In this heat recovery power generator, the steam Rankine cycle is improved so that heat can be efficiently recovered from the exhaust heat of a relatively low temperature.
Since the steam can be effectively used up to the low pressure level, the energy recovery efficiency can be improved and the steam condition on the low temperature / low pressure side of the steam turbine Rankine cycle can be improved.

Further, in this heat recovery power generator, the power obtained by recovering the heat of the exhaust heat of a relatively low temperature can be used for power generation, compressor drive, and heat pump drive. It is possible to select and substitute a part of electric power or turbine driving steam obtained by burning fuel, improve final energy efficiency, and protect the global environment.

Further, in this heat recovery power generation device, an absorption refrigeration cycle is constituted by the vapor absorber, the pump means, the vapor separator and the pressure reduction means, and the absorbent solution for absorbing water vapor or water is absorbed in the absorption refrigeration cycle. Circulate,
Even if the absorbent solution absorbs water vapor or water in the vapor absorber to cause a concentration decrease, this low-concentration aqueous absorbent solution separates the water vapor by heating in the vapor separator to increase the concentration. This high-concentration absorbent solution is decompressed and re-guided to the steam absorber, so that the absorbent solution can effectively and continuously maintain the absorption capacity of water vapor absorbed by the absorbent solution in the steam absorber. be able to. This water vapor absorption capacity can be further improved by cooling the inside of the vapor absorber.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram showing an embodiment of a heat recovery power generation device according to the present invention.

FIG. 2 is an entropy-enthalpy diagram of water vapor showing an example of state changes in the vapor expansion process during operation of the heat recovery power generator according to the present invention.

FIG. 3 is a Duhring diagram of a lithium bromide solution showing an example of the state change of the absorbent solution during the operation of the heat recovery power generator according to the present invention.

FIG. 4 is a configuration diagram on the steam expansion cycle side showing another embodiment of the heat recovery power generation device according to the present invention.

[Explanation of symbols]

 10 Absorption Refrigeration Cycle 11, 11A Steam Expansion Cycle 12 Steam Rankine Cycle 13 Cooling Device 14 Vapor Absorber 15 Pressurizing Pump (Pump Means) 16 Heating Device 17 Steam Separator 18 Condenser 19 Pressure Reduction Valve (Decompressor) 20 Cooler 24 Cooling Device 25 Booster pump (pump means) 26 Steam generator 32 Heating device 33, 33A Steam turbine 50 Turbine extraction reheat system 51 Reheater

Claims (8)

[Claims] 1. A vapor absorber that absorbs water vapor or water in a high-concentration absorbent solution to produce a low-concentration absorbent aqueous solution, pump means for taking out this absorbent aqueous solution and pumping it up, and this pump means. The absorption refrigeration cycle is performed by sequentially connecting a vapor separator that heats the absorbent aqueous solution sent by pressure to separate it into water vapor and a high-concentration absorbent solution, and a condenser that cools and condenses the separated water vapor. On the other hand, in this absorption refrigeration cycle, a steam expansion cycle including a steam generator for heating feed water by utilizing low temperature exhaust heat and a steam turbine for power extraction driven by steam from the steam generator is provided. In combination, the turbine exhaust working in the steam turbine is guided to the steam absorber and the high-concentration absorbent melt extracted from the bottom of the steam separator is combined. A heat recovery power generation device characterized in that the liquid is guided to a vapor absorber through a pressure reducing device. 2. The heat recovery system according to claim 1, further comprising booster pump means for taking out condensed water condensed by said condenser and pumping it up, and guiding the condensed water pumped up by said booster pump means to a steam generator. Power generator. 3. The steam absorber has a cooling device having a cooling pipe, and a high concentration absorbent solution is supplied to the steam absorber from the upper part, while turbine exhaust is supplied from the lower part. The heat recovery power generation device described. 4. The heat recovery power generation according to claim 1, wherein the steam separator is provided with a heating device for heating the low-concentration absorbent aqueous solution, and the low-concentration absorbent aqueous solution is allowed to flow down to the heating device in a heat-exchangeable manner. apparatus. 5. A cooler is provided in the pipe for guiding the high-concentration absorbent solution taken out from the bottom of the vapor separator to the vapor absorber, and the cooler is provided with the high-concentration absorbent solution from the vapor absorber. 2. The heat recovery power generation device according to claim 1, wherein the heat recovery power generation device is formed by a counterflow heat exchanger capable of exchanging heat with the low concentration absorbent aqueous solution. 6. The heat recovery power generation device according to claim 1, wherein the steam separator is set such that the internal pressure is lower than the internal pressure of the steam generator and higher than the internal pressure of the steam absorber during operation. 7. The steam generator and the steam separator are each provided with a heating device capable of exchanging low temperature waste heat and heat, and the heating device of the steam generator and the heating device of the steam separator are connected in series to provide a multi-stage. The heat recovery power generation device according to claim 1, which has a structure. 8. The steam turbine is constructed in a multi-stage structure, and a turbine extraction reheat system is taken out from the middle stage of the steam turbine. In this turbine extraction reheat system, a cooler provided in a condenser serves as a reheater. The heat recovery power generation device according to claim 1, wherein the heat recovery power generation device is configured and a downstream side of the turbine extraction reheat system is connected to a downstream side paragraph of the steam turbine.