KR19990087240A - How to generate rotary axial force in hydrogen fueled power plant - Google Patents

Abstract

Hydrogen 2 is used as a fuel source in power plants. Hydrogen (2) is combusted (8) in pure oxygen (1) to provide steam (71), which is then expanded in one or more power turbines (24, 26, 28), each steam It is reheated by another combustion of hydrogen with oxygen between successive turbines 10, 12. The heat available in the steam charged from the turbine 76 is recovered (6) by being transferred to hydrogen and oxygen prior to combustion. Since no hydrocarbon fuel or atmospheric air is used for combustion, NOx generation is eliminated and only the emissions 77 from the power plant are water.

Description

How to generate rotary axial force in hydrogen fueled power plant

In conventional power plants, hydrocarbon fuels such as natural gas or distilled oil are burned in air to provide hot gases. In gas turbine power plants, hot gases, typically compressed to about 1000-1500 kPa (150-200 psia), are expanded in the turbine to provide axial force. In steam turbine power plants, hot gases transfer heat to the feed water to generate steam, which is then expanded in the steam turbine to provide axial force. In both cases, the turbine drives a load, such as an electric generator or compressor, to deliver useful axial force.

Unfortunately, combustion of hydrocarbon fuels in air results in the formation of nitrogen oxides ("NOx") that are considered air pollutants. During combustion, NOx first converts atmospheric nitrogen into combustion air for three sources, namely (i) NOx, commonly referred to as “thermal NOx”, and (ii) HN ₃ in the fuel for NOx. From conversions based on native nitrogen mixtures such as (ammonia) and HCN, and (iii) the action between atmospheric nitrogen and hydrocarbon fragments formed from the collapse of hydrocarbons in fuels commonly referred to as "prompt NOx" Is generated.

Combustion of hydrogen fuel in pure oxygen will remove NOx as a whole because there is no hydrocarbon and no atmospheric nitrogen to generate prompt and fuel based NOx. Combustion for rocket engines is typically generated by burning liquid hydrogen in liquid oxygen. However, unlike rocket engines, power plant turbines must operate without degradation for a long time and must be able to effectively use the energy available from the fuel.

Therefore, it is desirable to provide an effective method of supplying axial force without generating NOx by burning hydrogen fuel in oxygen in a turbine power plant.

Summary of the Invention

Accordingly, it is an object of the present invention to provide a method of supplying axial force without generating NOx by burning hydrogen fuel in oxygen in a turbine power plant.

In summary, this object is not only an object of the present invention, but also (i) combusts the flow of compressed hydrogen in the flow of compressed oxygen in the combustor, consuming at least a portion of the compressed oxygen flow and Providing a flow, (ii) expanding the flow of hot compressed steam to provide a flow of at least partially expanded steam, and providing axial force by at least a portion of the expansion being achieved in the turbine; Iii) achieving a method of rotationally generating axial force comprising transferring heat from at least partially expanded flow of steam to at least one of a flow of compressed hydrogen and compressed oxygen prior to its combustion.

In a preferred embodiment of the invention, the flows of hydrogen and oxygen are compressed above their highest pressures before their combustion, and the step of transferring heat from the flow of expanded steam provides heat to both flows of compressed hydrogen and oxygen. Delivery.

The present invention relates to a method of burning hydrogen in a turbine power plant. In particular, the invention relates to a power plant in which hydrogen is combusted in oxygen and exhaust heat is recovered by a recoverer.

1 is a schematic diagram of a first embodiment of a turbine power plant according to the invention, in which all of the oxygen for combustion of hydrogen fuel is supplied to the first combustor after oxygen has passed through one or more cooling flow paths,

FIG. 2 is a schematic diagram of a second embodiment of a turbine power plant according to the present invention in which only oxygen stoichiometry for hydrogen fuel is supplied to each combustor. FIG.

Referring to the drawings, like reference numerals refer to like elements, and FIG. 1 shows a schematic diagram of a first embodiment of the hydrogen fueled power plant of the present invention. The first component of the power plant is a load (not shown), such as an oxygen source (1), a hydrogen source (2), a recoverer (6), first, second and third combustors (8, 10, 12), an electric generator. There are respective high, medium and low pressure power turbines 14, 16, 18 that drive the engine. The turbine is preferably of the conventional type and comprises a plurality of different rows of stationary vanes and rotating blades. The stationary vanes are fixed to the cylinder, and the rotary blades are fixed to a centrally arranged rotation axis. The combustor may be of a conventional type used in gas turbines or may be of special design.

Preferably, oxygen 30 from oxygen source 1 is at about 143 ° K (258 ° R) or cooler temperature and oxygen is a cryogenic liquid. Preferably, boost compressor 3 raises the pressure of oxygen above its supercritical pressure for oxygen at about 4,970 kPa (720 psia), more preferably up to about 34,500 kPa (5,000 psia). . Compressed oxygen 32 then flows through recoverer 6 where the oxygen is heated, preferably to about 540 ° C. (1,000 ° F.). Since the oxygen 32 is preferably compressed above its critical pressure, the heated oxygen 34 released from the recoverer remains primarily in the liquid state. However, if sub-critical pressure oxygen is supplied to the recoverer 6 which is lower than the critical pressure including oxygen in gaseous state, the heated oxygen 34 will be in gaseous state.

The recoverer has a heat transfer surface formed therein that allows heat to flow from the low pressure steam 76 described below to compressed oxygen 32 without contact between oxygen and steam. The recoverer 6 can be cellular and tubular, with compressed oxygen 32 flowing through the finned tube and low pressure steam 76 flowing over the tube.

From the recoverer 6, the heated and compressed oxygen 34 is divided into three vapors 38, 40, 42. Oxygen vapor 38 flows through a cooling flow path 24 formed in the high pressure turbine 14, the high pressure turbine cools the turbine component, and the turbine component flows through the high pressure turbine 14. It is not excessively heated by the hot compressed steam / oxygen mixture 71. Turbine components extending through the cooling flow path 24 may include rotating blades and stationary vanes. Using principles known in the art, the blades and vanes have cooling fluid passages formed therein, the cooling flow passages transferring heat from the hot steam / oxygen mixture 71 to the blades and vanes, and subsequently It is delivered to the oxygen 38 flowing through the cooling path 24, thereby heating the oxygen 38 and cooling the blades and vanes. The other heated oxygen 39, which is preferably heated to about 650 ° C. (1,200 ° F.), is then discharged from the cooling flow path 24 and exits the turbine. Equally, oxygen vapors 40, 42 flow through the cooling flow path 26 to the medium and low pressure turbines 16, 18, respectively.

Preferably, the cooling flow paths 24, 26, 28 are of closed loop type and all oxygen 38, 40, 42 entering the cooling flow path is from the turbines 14, 16, 18. Is released. As an alternative, for the purpose of effective cooling, any amount of oxygen 38, 40, 42 flows from the cooling flow paths 24, 26, 28 into the steam / oxygen mixture 71-76 flowing through the turbine. Can be.

Through the preferred embodiment, the compressed oxygen 34 is used as a cooling fluid for the turbine component, and the turbine also cavities oxygen and hydrogen exclusively or by using separate oxygen and hydrogen cooling flow paths through the selected turbine component. Is cooled by the compressed hydrogen (54). As a variant, such cooling may be achieved by recycling the vapor from the recoverer, as described below.

Returning to FIG. 1, the steam of the other heated and compressed oxygen 39, 41, 43 released from the turbines 14-18 is then directed to the first combustor 8.

Preferably, hydrogen 50 from hydrogen source 1 is 17 ° K (30 ° R) or lower temperature, which is a cryogenic liquid. The boost compressor 4 preferably raises the pressure of the hydrogen 50 at about 1,280 kPa (185 psia), more preferably at about 34,500 kPa (5,000 psia) above the supercritical pressure for hydrogen. Compressed hydrogen 52 then flows through recoverer 6 which is heated in a manner similar to compressed oxygen 32 and preferably to about 540 ° C. (1,000 ° F.). Since the hydrogen 32 is preferably compressed above its critical pressure, such heating is achieved without changing the state so that the heated hydrogen 54 released from the recoverer is generally in the liquid state. However, if hydrogen lower than the critical pressure containing hydrogen in the gaseous state is supplied to the recoverer 6, the heated hydrogen 54 will be in the gaseous state.

As in the case of oxygen 32, the recoverer has a heat transfer surface formed therein, which allows the heat to flow from the low pressure steam 76 to the compressed hydrogen 52 without contact between the hydrogen and the vapor. do.

From the recoverer 6, the heated and compressed hydrogen 54 is separated into three vapors 56, 58, 60 which are directed to the first, second and third combustors 8, 10, 12, respectively. As will be described below, the pressure of the steam / oxygen mixtures 73-76 flowing through the medium and low pressure turbines 16, 18 is less than the pressure flowing through the high pressure turbine 14. Thus, in a preferred embodiment of the present invention, hydrogen vapors 58, 60 are partially expanded into small power turbines 20, 22 before they are introduced into second and third combustors 10, 12, respectively. This allows some of the energy that is expanded to compress the hydrogen 52 and recovers it as useful.

In the embodiment of the invention shown in FIG. 1, all of the oxygen 44 necessities for the combustor of three hydrogen vapors 56, 58, 60 in each of the three combustors 8, 10, 12 are defined. 1 is introduced into the combustor 8. As a result, in the first combustor 8, the first portion 56 of all hydrogen fuel is combusted with a portion of the oxygen 44, and combustion in the first combustor 8 is such as oxygen enriched / fuel lean. It may be a feature. This combustion prevents the temperature from becoming too high, as would be generated if hydrogen was stoichiometrically fired.

The product of the combustion of hydrogen and oxygen in the first combustor is pure water in the form of supercritical steam. As a result, the first combustor 8 releases a hot compressed gas 71 comprising a mixture of supercritical steam and oxygen. Preferably, sufficient hydrogen 56 is combusted in the first combustor 8 and heats the high pressure steam / oxygen mixture 71 to about 1,650 ° C. (3,000 ° F.).

From the first combustor 8, the high pressure steam / oxygen mixture 71 is expanded to medium pressure in the high pressure turbine 14 to provide a useful axial force. In this way, the temperature of the vapor / oxygen mixture 72 is preferably reduced to about 810 ° C. (1,500 ° F.). The medium pressure steam / oxygen mixture 72 discharged from the high pressure turbine 14 is then reheated in the second combustor 10, and the second portion 59 of hydrogen fuel in the second combustor is the steam / oxygen mixture 72. It burns with a part of oxygen in). Since not all residual oxygen is combusted in the second combustor 10, combustion may also be characterized as oxygen enriched / fuel lean. Combustion in the second combustor 10 preferably continues to raise the temperature of the medium pressure steam / oxygen mixture to about 1,650 ° C. (3,000 ° F.).

The reheated intermediate steam / oxygen mixture 73 from the second combustor 10 is then expanded again to low pressure in the medium pressure turbine 16 to provide additional axial force. In this way, its temperature is reduced again, preferably to about 810 ° C (1,500 ° F). The low pressure steam / oxygen mixture 74 discharged from the medium pressure turbine 16 is then reheated in the third combustor 12, and within the third combustor the third portion 57 of the hydrogen fuel is steam / oxygen mixture 74. Combustion with the remaining portion of oxygen in) preferably continues to raise the temperature of the low pressure steam / oxygen mixture to about 1,650 ° C. (3,000 ° F.).

Since oxygen is preferably consumed up to combustion in the third combustor 12, this combustion may be characterized as stoichiometric, and the fuel released by the third combustor is generally pure steam.

The low pressure steam 75 heated from the third combustor 12 is further expanded in the low pressure turbine 18, the low pressure turbine of which is preferably reduced back to about 810 ° C. (1,500 ° F.). Thus, the low pressure turbine 18 still provides a lot of axial force. Preferably, the pressure of the expanded steam 76 discharged from the low pressure turbine 18 is lower than atmospheric pressure, such as about 7 kPa (1 psia).

Preferably, the overall pressure drop represented by the fuel from the first combustor 8 to the recoverer 6 is separated between approximately high pressure, medium pressure and low pressure turbines 14, 16 and 18, respectively. The expansion rate in the turbine is the cube root of three.

In a preferred embodiment, although combustion in the third combustor 12 consumes all residual oxygen, it may be more environmentally desirable to use lean combustion in the third combustor 12 and discharge from the third combustor. The fuel being made will accept some excess oxygen. Moreover, although the embodiment shown in FIG. 1 uses three turbines 24, 26, 18, more or fewer turbines will also be used to optimize thermodynamic efficiency and cost.

The vapor 76 exiting from the low pressure turbine 18 is directed to the recoverer 6, where the temperature is further reduced by transferring heat to the incoming flow of cryogenic oxygen and hydrogen 32, 52, respectively. . By transferring heat from the steam exhausted from the low pressure turbine 16 to the oxygen 32 and hydrogen 52 fuels, the optimal utilization makes the input of energy within the cycle to maximize thermal efficiency. The temperature of the vapor 77 exiting the recoverer 6 will affect the temperature and mass flow rate of the incoming steam 76 as well as the inlet and outlet temperature and flow rate of oxygen and hydrogen. Preferably, the vapor 77 will be effectively cooled and condensed in the recoverer 6. The condensate 77 is then discharged for use as treated water or discharged to the environment. As a variant, the recoverer 6 may only partially cool the vapor 76, in which case the partially cooled and expanded steam exiting the recoverer will then be directed to a condenser (not shown).

Therefore, according to the present invention, the rotational axial force is effectively provided without generation of NOx. In addition, the discharge from the power plant is pure water, which can be safely released into the environment after most of it is slightly cooled.

2 shows a second embodiment of the present invention. In this embodiment, oxygen 132 and hydrogen 152 are supplied by oxygen and hydrogen sources 101 and 102, respectively. Preferably, oxygen 132 and hydrogen 152 are compressed above their critical pressures, but are not cryogenic, such as at temperatures around 20,500 kPa (3,000 psia). Oxygen 132 and hydrogen 152 are heated in recoverer 106 by transfer of heat from low pressure steam 176, as described above. In this embodiment, oxygen 134 and hydrogen 154 are preferably heated to about 260-540 ° C. (500-1,000 ° F.).

From recoverer 6, heated oxygen 134 and heated hydrogen 154 are each separated into three vapors. The first portion 144 of oxygen and the first portion of hydrogen 160 are combusted in the first combustor 108. However, in this embodiment, combustion is generally stoichiometric so that substantially all of the oxygen 144 is consumed by burning all of the hydrogen 160. As a result, the first combustor 108 generally releases pure steam 171, ie, steam at a pressure greater than the supercritical pressure of the steam (about 21,840 kPa (3,168 psia)) into a supercritical high pressure flow.

Despite the stoichiometric nature of the combustion, the temperature is prevented from becoming excessive by the introduction of the flow of supercritical steam 181, 188 into the first combustor 108, as described below, which is the combustion temperature. Adjust As a result, the high pressure supercritical steam 171 discharged from the first combustor 108 includes steam formed by combustion of oxygen 144 and hydrogen 160 as well as injection of steam 181 and 188. . Preferably, the supercritical steam 171 emitted by the first combustor 108 is at a pressure and temperature of about 20,500 kPa (3,000 psia) and 1,650 ° C. (3,000 ° F.), respectively.

From the first combustor 108, the high pressure supercritical steam 171 is partially expanded to medium pressure in the high pressure turbine 114 to provide useful axial force. In doing so, the temperature of the steam is preferably reduced to about 810 ° C. (1,500 ° F.). The medium pressure steam 172 released from the high pressure turbine 114 is then reheated in the second combustor 110, in which the second portion 159 of the hydrogen fuel is with the second portion 136 of oxygen. Is burned. In addition, combustion in the second combustor 110 is preferably carried out under generally stoichiometric conditions, and is provided with substantially pure medium pressure steam 173. Combustion in the second combustor 110 preferably raises the temperature of the medium pressure steam 173 to 1,650 ° C (3,000 ° F).

The reheated medium pressure steam 173 from the second combustor 110 is then further expanded to low pressure in the medium pressure turbine 116 to provide additional axial force. In doing so, this temperature is preferably reduced back to about 810 ° C. (1,500 ° F.). The low pressure steam 174 discharged from the medium pressure turbine 116 is then reheated in the third combustor 112, in which the third portion 157 of the hydrogen fuel is with the third portion 135 of hydrogen. Is burned. In addition, combustion in the third combustor 112 is preferably carried out under generally stoichiometric conditions, and is provided with a generally pure low pressure steam 175. Combustion in the third combustor 112 raises the temperature of the low pressure steam 175 to preferably about 1,650 ° C. (3,000 ° F.).

The reheated low pressure steam 175 from the third combustor 112 is then further expanded in the low pressure turbine 18, in which the temperature is preferably reduced back to about 810 ° C. (1,500 ° F.). Thus, the low pressure turbine 118 still provides a lot of axial force. Preferably, the pressure of the expanded steam 176 discharged from the low pressure turbine 118 is lower than the atmospheric pressure as above, and the overall pressure drop represented by the fuel is high, medium and low pressure turbines 114, 116, 118). Moreover, although the embodiment shown in FIG. 2 uses three turbines 14, 16, 18, more or fewer turbines may also be used as described above.

Steam 176 exiting from the low pressure turbine 118 is directed to the recoverer 106, where the temperature is up to the incoming flow of oxygen 132 and hydrogen 152, respectively, as described above. Further reduced by delivery to compressed water 179. Cooled steam 177 is then directed to condenser 198. Condensate from condenser 198 is split into two vapors 178, 199. Vapor 199 is released for other use or to the environment.

Condensation vapor 178 is compressed by pump 200 to a pressure above its critical pressure, preferably to about 20,500 kPa (3,000 psia). Although compressed water 179 may be injected directly into first combustor 108 to control the combustion temperature, compressed water 179 preferably flows first through recoverer 106, which recovers its temperature. Is raised by transferring heat from the expanded steam 176. Inside recoverer 106, water 179 is divided into two vapors 180, 181.

The first vapor 180 is discharged from the recoverer 6 just like the flow of supercritical steam after flowing through only part of the heat transfer device. Preferably the temperature is raised to about 260 ° C (500 ° F). Steam 180 discharged from recoverer 106 is then divided into three streams 182, 184, and 186, each of which, as described above, is a high, medium and low pressure turbine 114, 116, 118. Flow through some of the cooling flow paths 124, 126, and 128 formed within the components of FIG. In each cooling flow path, heat is transferred to the steam, preferably raising the temperature to about 540 ° C. (1,000 ° F.). The flow of heated supercritical steam 183, 185, 187 exiting the turbine is then introduced into the first combustor 108 to cool the combustion temperature, as described above. 2 shows a closed loop turbine steam cooling apparatus, all or some of the steam destined for the cooling flow paths 124, 126, 128 may be discharged directly into the steam flowing through its respective turbine.

The second vapor of supercritical steam 181 from recoverer 106 is released after flowing through the entirety of the heat transfer device, the temperature of which rises above the temperature of steam 180 and preferably the turbine cooling flow path. Elevated temperatures, such as vapor flows 183, 185, and 187 discharged from 124, 126, and 128, to about 540 ° C (1,000 ° F). From recoverer 106, the second flow of heated supercritical steam is directed directly to first combustor 108.

In the embodiment shown in FIG. 2, the recoverer 106 is located downstream of the low pressure turbine 118, but the recoverer may also be advantageously located upstream of the low pressure turbine. This is achieved by reducing the pressure difference between the flow of compressed oxygen 132, hydrogen 152 and water 179 that flows through the recoverer on the one hand and the steam 176 that flows through the recoverer on the other hand. This will reduce the stress imposed on the heat transfer component. In such embodiments, the low pressure turbine 118 may be condensed and the low pressure combustor may be removed.

As described above, the present invention may be embodied in other specific forms without departing from the spirit or main characteristics of the present invention, and therefore, reference should be made in the appended claims rather than in the foregoing specification as indicating the scope of the invention.

Claims (20)

In the method of generating the rotational axial force, a) combusting a first flow of compressed hydrogen in a first combustor within a first flow of compressed oxygen, thereby consuming at least a first portion of the first flow of compressed oxygen, Providing a flow, b) expanding the first flow of the hot compressed steam to provide a flow of at least partially expanded steam, at least a portion of the expansion being achieved in the first turbine, thereby providing axial force; c) transferring heat from at least partially expanded steam to at least one of said first flows of compressed hydrogen and compressed oxygen prior to said combustion. The method of claim 1, Transferring heat from the flow of expanded steam includes transferring heat to the first flow of compressed hydrogen prior to its combustion. The method of claim 2, Compressing the first flow of hydrogen substantially before the combustion and before the transfer of heat thereof from the expanded steam. The method of claim 3, wherein Compressing the flow of hydrogen comprises compressing the hydrogen to a pressure at least equal to a critical pressure of the hydrogen. The method of claim 1, Transferring heat from the flow of expanded steam includes transferring heat up to the first flow of compressed oxygen prior to its combustion. The method of claim 5, Compressing the first flow of oxygen prior to its combustion and its transfer of heat from the expanded steam. The method of claim 6, Compressing the first flow of oxygen comprises compressing the oxygen to a pressure at least equal to a critical pressure of the oxygen. The method of claim 1, Transferring heat from the flow of expanded steam comprises transferring to both the flow of compressed hydrogen and the flow of compressed oxygen prior to its combustion. The method of claim 1, Only a first portion of the oxygen in the first flow of compressed oxygen is combusted with the first flow of compressed hydrogen in the first combustor so that the combustion is heated and compressed along the hot compressed steam. Generating a mixture of oxygen, wherein the mixture of compressed oxygen and steam continues to expand in the first turbine, producing a partially expanded mixture of oxygen and steam. The method of claim 9, Combusting a second flow of hydrogen compressed in the mixture of partially expanded oxygen and steam in a second combustor, consuming a second portion of the oxygen in the first flow of compressed oxygen, reheating and partially expanding Generating a rotational axial force which provides a flow of purified steam. The method of claim 10, Expanding the flow of the reheated and partially expanded steam in a second turbine to supply additional axial force. The method of claim 1, Substantially all of the oxygen in the first flow of compressed oxygen is combusted with the first flow of compressed hydrogen. The method of claim 12, Wherein said combustion is generally stoichiometrically generated. The method of claim 1, Condensing the at least partially expanded steam after the transfer of heat therefrom to provide water. The method of claim 14, a) compressing the water; b) introducing the compressed water into the first combustor for cooling the flow of the hot compressed steam provided by the combustion. The method of claim 14, a) compressing the water; b) transferring heat to the compressed water to provide heat to provide a flow of cooling steam; c) introducing a first flow of cooling steam into the first combustor for cooling the first flow of the hot compressed steam provided by the combustion. The method of claim 1, The compressed steam is only partially expanded in the first turbine, introducing a second flow of compressed hydrogen and a second flow of compressed oxygen into the flow of the partially expanded steam, the same in the second combustor By combusting, providing a flow of reheated partially expanded steam. The method of claim 17, Expanding the flow of the reheated partially expanded steam in a second turbine to provide additional axial force. The method of claim 1, Cooling heat the first turbine and heating the oxygen by transferring heat from the first turbine to the first flow of compressed oxygen. The method of claim 19, Transferring heat from the first turbine to a first flow of compressed oxygen comprises at least a portion of the flow of compressed oxygen through the first turbine.