US20180187573A1

US20180187573A1 - Steam power plant

Info

Publication number: US20180187573A1
Application number: US15/740,297
Authority: US
Inventors: Rudolf Gutscher
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-06-30
Filing date: 2016-06-21
Publication date: 2018-07-05
Also published as: AT517535A1; EP3317497B1; WO2017001241A1; PL3317497T3; EP3317497A1; AT517535B1; CN107849946A

Abstract

A steam power plant includes a working medium circuit having a first heat exchanger system to vaporize a working medium, a steam turbine system, a second heat exchanger system to condense the working medium, and a pump system to feed the condensed working medium into the first heat exchanger system. An absorption heat pump having an expeller system and a refrigerant circuit which at least partially includes the first heat exchanger system and the second heat exchanger system, is configured to transfer thermal energy from the second heat exchanger system to the first heat exchanger system. Leading from a turbine extraction point of the steam turbine system via the expeller system of the absorption heat pump line to a feed point in the working medium circuit is an expulsion line, with the working medium in the expulsion line providing thermal energy for an expulsion process of the absorption heat pump.

Description

The invention relates to a steam power plant according to the preamble of Patent Claim 1.
Steam power plants are known, in which the exhaust steam from steam turbines or steam machines is liquefied in a condenser system before it can be pumped again to the heat generator, for example, reactor, steam boiler, or gas and steam plant.
This has the disadvantage that the condensation heat is lost as heat loss.
The object of the present invention is therefore to specify a steam power plant of the type mentioned at the outset, using which the mentioned disadvantages can be avoided, and which has a high efficiency.
This is achieved according to the invention by the features of Patent Claim 1.
The efficiency of the steam power can thus be increased and therefore emissions of the steam power plant can be avoided. Furthermore, conventional cooling systems, for example, river-water cooling, dry cooling systems, air coolers, or cooling towers, depending on the scope of the embodiment of the invention, can be replaced or partially replaced. The condensation heat can be at least partially reclaimed by the absorption heat pump. In this case, the additional energy consumption of the absorption heat pump caused by the expeller system of the absorption heat pump can be provided by the working medium itself. Due to the turbine extraction, steam is used for the expeller system which could already emit a part of its available energy into the steam turbine system, whereby the energy available for obtaining current is only reduced slightly. The additional energy consumption for the absorption heat pump thus remains less than the condensation heat which is reclaimed and usable by the absorption heat pump. An overall system can thus be provided, which has an increased efficiency and is easily implementable as a whole. Using the present invention, it is also possible to implement the regular operation of a plant implemented in this manner in a sensible manner.
Furthermore, the invention relates to a method for operating a steam power plant according to Patent Claim 13.
The object of the invention is therefore furthermore to specify a method of the type mentioned at the outset, using which the mentioned disadvantages can be avoided, and which has a high efficiency.
This is achieved according to the invention by the features of Patent Claim 13.
The advantages of the method correspond in this case to the advantages of the steam power plant.
The dependent claims relate to further advantageous embodiments of the invention.
Reference is expressly hereby made to the wording of the patent claims, whereby the claims are incorporated into the description at this point by reference and are considered to be reproduced verbatim.

The invention will be described in greater detail with reference to the appended drawings, which merely illustrate preferred embodiments by way of example. In the figures:

FIG. 1 shows a conventional steam power plant as a schematic illustration;

FIG. 2 shows an absorption heat pump as a schematic illustration;

FIG. 3 shows a first preferred embodiment of a steam power plant as a schematic illustration;

FIG. 4 shows a second preferred embodiment of a steam power plant as a schematic illustration;

FIG. 5 shows a third preferred embodiment of a steam power plant as a schematic illustration; and

FIG. 6 shows a fourth preferred embodiment of a steam power plant as a schematic illustration.

FIGS. 3 to 6 show preferred embodiments of a steam power plant 1 having a working medium circuit 2 for a working medium, wherein the working medium circuit 2—viewed in the flow direction of the working medium—comprises a first heat exchanger system 3 for vaporizing the working medium, a steam turbine system 4, a second heat exchanger system 5 for condensing the working medium, and a working medium pump system 6. The first heat exchanger system 3 is provided to supply the working medium with thermal energy until it at least vaporizes. Vice versa, the second heat exchanger system 5 is provided to cool the working medium until it at least condenses. Water can particularly preferably be used as the working medium.
It is provided that at least one refrigerant circuit 7 of an absorption heat pump 8 at least partially comprises the first heat exchanger system 3 and at least partially comprises the second heat exchanger system 5, wherein the absorption heat pump 8 is designed to move thermal energy from the second heat exchanger system 5 to the first heat exchanger system 3, and an expulsion line 9 leads from a turbine extraction point 11 of the steam turbine system 4 via an expeller system 12 of the absorption heat pump 8 to a feed point 13 into the working medium circuit 2, wherein the working medium in the expulsion line 9 provides thermal energy for an expulsion process of the absorption heat pump 8.
Furthermore, a method for operating a steam power plant 1 in regular operation is provided, wherein, in a working medium circuit 2, a working medium is vaporized in a first heat exchanger system 3 and supplied to a steam turbine system 4, wherein the working medium is condensed after the steam turbine system 4 in a second heat exchanger system 5 and supplied via a working medium pump system 6 back to the first heat exchanger system 3, characterized in that by means of at least one refrigerant circuit 7 of an absorption heat pump 8, thermal energy is moved from the second heat exchanger system 5 to the first heat exchanger system 3, at a turbine extraction point 11, a part of the working medium branches from the steam turbine system 4 into an expulsion line 9, liquefies in an expeller system 12 of the absorption heat pump 8, and is returned back into the working medium circuit 2 at a feed point 13, wherein thermal energy is provided for an extraction process of the absorption heat pump 8 by this part of the working medium.
Thermodynamic cyclic processes are known both as counterclockwise and also as clockwise processes. Clockwise processes are predominantly used for the operation of engines and working machines in thermal power plants such as power plants, and counterclockwise processes are predominantly used for heat pump or refrigerator processes. The processes referred to as counterclockwise or clockwise relate with respect to this direction specification to the conventional thermodynamic direction specification and not to the flow direction of the respective working medium.
The combination of thermodynamic counterclockwise absorption heat pump processes in the refrigerant circuit 7 with a thermodynamic clockwise Clausius Rankine cyclic process in the working medium circuit 2 has proven to be advantageous. Namely in such a way that the thermal energy loss of the working medium circuit 2 in the second heat exchanger 5, which was previously dissipated by means of coolant media, can now be used for vaporizing a coolant suitable for this purpose and therefore for operating a counterclockwise cyclic process, and is withdrawn from the clockwise cyclic process, on which the operation of engines or working machines are based, at a point suitable for this purpose, namely the second heat exchanger system 5. The withdrawn waste heat is thereafter returned again at another suitable point of the same thermodynamic clockwise cyclic process from which this heat originates, with additional increase of the energy content of the absorption heat pump cyclic process, into the clockwise cyclic process, namely at the first heat exchanger system 3, whereby the efficiency of the thus resulting newly combined, simultaneously operated overall process, which is coupled to separate material flows, of the two cyclic processes used, is increased.
The efficiency of the steam power plant 1 can thus be increased and therefore emissions of the steam power plant 1 can be avoided. Furthermore, conventional cooling systems, for example, river-water cooling, dry cooling systems, air coolers, or cooling towers can be partially or entirely avoided or replaced, respectively, depending on the scope of the embodiment of the invention. The condensation heat can be at least partially reclaimed by the absorption heat pump 8. In this case, the additional energy consumption of the absorption heat pump 8 caused by the expeller system of the absorption heat pump 8 can be provided by the working medium from the working medium circuit 2 itself. Steam is used for the expeller system 12 by the turbine extraction point 11, which could already emit a part of its available energy into the steam turbine system 4, whereby the energy available for obtaining current is only slightly reduced. The additional energy consumption for the absorption heat pump 8 thus remains less than the usable condensation heat reclaimed by the absorption heat pump. An overall system can thus be provided, which has an increased efficiency as a whole and is easily implementable. Using the present invention, it is also possible to advantageously implement the regular operation of a system designed in this manner.
Dashed lines in FIGS. 1 to 6 indicate each type of the vaporized working medium, in particular water steam, and its pipeline and transportation systems. Solid lines in the following illustrations indicate each type of the condensed working medium from the working medium circuit 2 and its pipeline and transportation systems. Dot-short-dashed lines in the following illustrations indicate any type of the vaporized coolant and its pipeline and transportation systems. Dot-long-dashed lines in the following illustrations indicate any type of the condensed coolant and its pipeline and transportation systems. Closely dotted lines in the following illustrations indicate any type of the coolant water and its pipeline and transportation systems. Double-short-dashed lines in the following illustrations indicate any type of a strongly enriched solution with coolant and coolant solvent and its pipeline and transportation systems, i.e., so-called strong solutions.
Short-dashed lines in the following illustrations indicate any type of weakly enriched solutions or only still the solvent of a refrigerant solution and its pipeline and transportation systems, i.e., so-called lean solutions. Black arrows identify the flow direction of a system medium in its associated system.
In FIGS. 1 to 6, known details of steam power plants such as feed water containers, feed water preheaters, and the like are not shown for the sake of comprehensibility, but can be used if needed.
FIG. 1 shows, in a form illustrated as a process diagram, a simplified conventional working medium circuit 2, which can be operated as a clockwise thermodynamic Clausius Rankine cyclic process and on which known thermally operated plants, for example, thermal power plants, cogeneration plants, and so-called gas and steam turbine power plants, are based as a simplified main process. More extensive additional assemblies, which improve efficiency, for example, such as feed water preheater, intermediate superheater, but also system-relevant assemblies such as feed water containers etc. are not shown in the following descriptions of FIG. 1 to FIG. 6 because they are known, since this would excessively restrict the comprehensibility of the description of the invention.
In FIG. 1, the working medium pump system 6 conveys the condensate of the water steam, which is preferably used as the thermal carrier and working medium of the present clockwise thermodynamic Clausius Rankine cyclic process, with pressure increase to the first heat exchanger system 3, and provides it thereto as so-called feed water. In FIG. 1, the first heat exchanger 3 solely comprises a steam generator system 14.
A heat energy supply system 24 provides the required thermal energy for generating the water steam in the steam generator system 14 in FIG. 1. The heat energy supply system 24 stands for any type of fuel and/or heat energy supply system, for the purpose of generating and supplying heat for a steam generator system 14 heated thereby. Waste heat of gas turbine exhaust gas can also be used for this purpose, for example, and this is therefore also understood to be included. The heat energy supply system 24 therefore stands for any form of heat supply system for generating vaporized working medium. In the steam generator system 14, the condensate, also called feed water before the steam generator system 14, is vaporized by the supply of thermal energy, and water steam is generated having higher pressure and temperature than in the second heat exchanger system 5, which only comprises a coolant water condensation unit 20 in FIG. 1.
Finally, the generated water steam flows to the steam turbine system 4 through a fresh steam line 25. The steam turbine system 4 stands for any type of steam turbine system or engine system operated using steam for the purpose of converting thermal, kinetic, and potential energy into mechanical energy. Using the steam turbine system 4, a part of the energy of the generated water steam is converted into mechanical energy and transmitted to a working machine system or a generator system 26, which is coupled to the steam turbine system 4, whereby this transmitted energy component is largely made technically usable. The generator system 26 stands for any type of generator system coupled to an engine system, or another working machine system, for the purpose of generating electrical energy or performing mechanical work.
After the steam turbine system 4, water steam of lower temperature and lower pressure than before the steam turbine system 4 flows therefrom into the second heat exchanger system 5 in order to condense. In the second heat exchanger system 5, the water steam is finally condensed, whereby the phase of the water steam is converted from vapor into liquid.
This condensation takes place in FIG. 1 in a conventional steam power plant 1 with the aid of coolant water or other coolant media, for example, air. The coolant medium flows for this purpose via a coolant water feed line 10 into the second heat exchanger system 5, then largely absorbs the vaporization heat or condensation heat, respectively, of the water steam in the second heat exchanger system 5, whereby the introduced water steam changes its phase from vapor to liquid. The absorbed heat which is now located in the coolant medium is decoupled from the process by a coolant water return line 22 and frequently discarded. The recirculation of this waste heat has previously not been the case in most plants, since the heat is provided in a form which is no longer advantageously technically usable with respect to its thermodynamic state variables. This aspect is responsible for the greatest thermodynamic loss of the entire clockwise Clausius Rankine cyclic process in the working medium circuit 2. After the second heat exchanger system 5, the liquid condensate of the water steam is returned back to the process with the aid of the working medium pump 6 and the circuit of the working medium begins again, wherein the decoupled heat loss content is lost to the surroundings.
FIG. 2 shows by way of example, in a form illustrated as a process diagram, a known absorption heat pump 8. In this case, the refrigerant is vaporized by means of external heat supply of a material flow to be cooled in a vaporization unit 19. The refrigerant vapor is then conducted into an absorber system 27, where it is brought into solution using a suitable solvent. The strong solution, preferably ammonia with water, but also other known solutions for operating absorption heat pumps 8, is then suctioned by means of a suitable solvent pump system 28 and conducted into a solution heat exchanger system 29, designed in particular as a two-flow heat exchanger, where the lean solution, which is supplied from the expeller system 12 via the return line 39, transfers further heat to the enriched solution. The rich solution additionally charged with heat then flows into the adjoining expeller system 12, which is operated using the supply of external energy. In this case, in the expeller system 12, the refrigerant is thermally expelled from the saturated solution and the pressure, temperature, and energy content of the refrigerant, which is now in the form of vapor, are increased. This refrigerant vapor is then supplied to a liquefying unit 15, which is also used at the same time as a heat exchanger for heat transfer to an external material flow to be heated. In this case, the previously introduced heat is transferred to the external material flow and at the same time the refrigerant vapor is also condensed in the liquefying unit 15. The heat to be dissipated is dissipated from the heated material flow. The unsaturated solvent is discharged in the form of a lean solution from the expeller system 12 via the return line 39 and the solution heat exchanger system 29, where it emits its useful heat. A solvent throttle system 31 throttles the lean solution such that it can be returned via the return line 39 into the absorber system 27, to absorb refrigerant again and therefore to convert the non-enriched, lean solution into an enriched, strong solution. The condensed refrigerant is also supplied to a refrigerant throttle system 30 and thermodynamically throttled such that it again corresponds to its starting state. Thereafter, it is supplied to the vaporization unit 19, to again withdraw heat from the external material flow to be cooled and to be vaporized at the same time and be available for further consistently repeatable heat absorption.
The invention is based on the concept of reusing heat loss energy of a clockwise thermodynamic cyclic process for operating engines and/or working machines. Previously, this energy was in the form which was not thermodynamically sensible to reuse after the condensation with respect to the thermodynamic properties of the medium water as a consequence of the necessity for condensation of the water steam in the coolant water condensation unit 20 of the second heat exchanger system 5 for the operation of the clockwise Clausius Rankine process. It remained predominantly unused and was dissipated by means of coolant medium to the surroundings. The reuse of the heat loss is achieved in that, as described above, the clockwise cyclic process, coupled with one or more counterclockwise cyclic processes connected in parallel, which are operated as the absorption heat pump 8, in the first heat exchanger system 3 and the second heat exchanger system 5, is operated simultaneously in regular operation and the heat then to be reused is withdrawn at a point suitable for this purpose, by means of the counterclockwise cyclic process or processes, from the clockwise cyclic process and, with the aid of the counterclockwise cyclic process or processes, which are operated as the absorption heat pump 8, the thermodynamic state variables of the refrigerant change in a suitable manner, so that the withdrawn heat of the clockwise cyclic process returns to this Clausius Rankine process itself, with the aid of the absorption heat pump 8, at a point suitable for this purpose.
In this case, the heat required for expelling the refrigerant is withdrawn during regular operation of the plant from a turbine extraction point 11. The withdrawal point is selected in this case such that the required withdrawal vapor energy content is available for the operation of the expeller system 12. In particular, it can be provided that the withdrawal pressure at the turbine extraction point 11 is higher than the pressure of the condensed working medium for the boiler feed in the first heat exchanger 3, so that the working medium can be returned into the working medium circuit 2 of the clockwise cyclic process after passing through the expeller system 12.
It can particularly preferably be provided that the second heat exchanger system 5 has the vaporization unit 19 of the refrigerant circuit 7. In particular, the vaporization unit 19 can be designed as a heat exchanger, in which the working medium circuit 2 is connected to the primary side of the vaporization unit 19, and the refrigerant circuit 7 is connected to the secondary side of the vaporization unit 19.
It can preferably be provided that the first heat exchanger system 3 has the steam generator system 14 of the working medium circuit 2 and the liquefying unit 15 of the refrigerant circuit 7, and the liquefying unit 15 is designed as a heat exchanger between working medium circuit 2 and refrigerant circuit 7. In the first heat exchanger system 3, the working medium can therefore be preheated in the liquefying unit 15 and subsequently be vaporized in the steam generator system 14.
Furthermore, it can be provided that the feed point 13 of the expulsion line 9 into the working medium circuit 2 is arranged between the steam generator system 14 and the liquefying unit 15. In this case, the return feed of the working medium from the expulsion line 9 is particularly energetically advantageous at this point.
In particular, it can be provided that a further working medium pump system 16 is arranged between the feed point 13 of the expulsion line 9 in the working medium circuit 2 and the steam generator system 14. The working medium can thus be reliably brought to the pressure required for feeding into the steam generator system 14. If the working medium pump system 6 can be dimensioned large enough and the pressures in the hot steam withdrawal points at the turbine extraction point 11 and/or the fresh steam extraction point 17 permit this, omitting the further working medium pump system 16 is possible.
In addition, for the startup and shutdown of the steam power plant 1, as long as the steam turbine system 4 is not yet in operation, or in case of malfunction as a redundancy, the expeller system 12 can be supplied by means of fresh steam withdrawal from the fresh steam line 25. The switchover to the regular operation is preferably to take place as rapidly as possible, since the fresh steam has higher energetic value than the steam from the turbine extraction point 1:1 and can therefore be energetically used in the steam turbine system 4 until reaching the turbine extraction point 11, so that a higher overall efficiency of the plant results than in the case of operation of the expeller system 12 by means of fresh steam. Due to the arrangement of both the fresh steam extraction point 17 and also the turbine extraction point 11, the energy consumption during startup operation and/or shutdown operation of the steam power plant 1 can be kept low. Furthermore, the advantage thus results that in the event of a load change of the steam power plant 1, as will become more frequently necessary due to the increased use of renewable energy in the networks, the absorption pump 8 can be operated flexibly, whereby the absorption pump 8 is not limited to a constant load of the steam power plant 1.
It can be provided in this case that the expulsion line 9 has on the intake side, in addition to the turbine extraction point 11, a predefinably closable fresh steam extraction point 17, which fresh steam extraction point 17 is arranged between the first heat exchanger system 3 and the steam turbine system 4. It can be provided in this case that the predefinably closable fresh steam extraction point 17 is closable by means of a fresh steam extraction valve 33, to later be able to switch over to the turbine extraction point 11.
Furthermore, the fresh steam extraction point 17 can be provided with a fresh steam extraction throttle 32, to adapt the fresh steam state to the expeller system 12. A throttle is a device for system pressure regulation and thermodynamic throttling of system media.
A steam forming station can preferably be used for the fresh steam extraction throttle 32, to regulate both the pressure and also the temperature. The injection water used for the steam forming station can be withdrawn in particular from working medium circuit 2, preferably between working medium pump system 6 and the steam generator system 14.
In particular in the case of a fresh steam extraction point 17, it can be provided that the turbine extraction point 11 is provided with a first backflow safeguard system 34. The backflow safeguard system 34 stands for any type of backflow safeguard system for the purpose of preventing the incorrect flow direction of system media, in this case of the working medium of the working medium circuit 2.
Furthermore, it can be provided that a predefinably closable bypass line 18 of the working medium circuit 2 leads from the fresh steam extraction point 17 to the second heat exchanger system 5. The bypass line 18 can be closed by means of a bypass valve 35. Furthermore, a second backflow safeguard system 36 can be arranged in the working medium circuit 2 after the steam turbine system 4, to prevent fresh steam from the bypass line 38 from reaching the outlet of the steam turbine system 4.
Furthermore, it can be provided in the method that in the startup operation and/or shutdown operation of the steam power plant 1, the working medium is guided past the steam turbine system 4 to the second heat exchanger system 5 and/or the expeller system 12 of the absorption heat pump 8. In this case, the working medium is guided past the turbine system 4.
In addition, until reaching provided steam parameters of the vaporized working medium or in case of malfunction, at least parts of the vaporized working medium can be discharged from the working medium circuit 2 via an outlet valve 37 to the surroundings, wherein in particular the mass flow of working medium discharged via the outlet valve 37 from the working medium circuit 2 is compensated for via an external process water supply 38. The provided steam parameters of the vaporized working medium, in particular pressure and temperature, can preferably be selected such that they are sufficient for operating the expeller system 12. An absolute pressure greater than 1 [bar_abs] is preferably provided here. The maximum pressure at the turbine extraction point is to be designed so that the energy content of the steam is sufficient for the operation of the expeller system 12 and the condensate is sufficient and can be recirculated as described above. In particular, it can be provided that the absolute pressure at the turbine extraction point 11 is at least 10% less than the intake pressure of the fresh steam from the fresh steam line 25 at the steam turbine system 25.
Furthermore, it can be provided in particular that the steam forming station is arranged in the expulsion line 9 before the expeller system 12 for pressure and temperature regulation.
FIG. 3 shows, in a form illustrated as a process diagram, a first preferred embodiment as a combination of the counterclockwise with the clockwise cyclic processes, as is implementable as an overall process, with the aid of an absorption heat pump 8. In this case, the refrigerant of the absorption heat pump 8 is vaporized by means of condensation heat of the exhaust steam of the steam turbine system 4 from the working medium circuit 2 in the vaporization unit 19 of the refrigerant circuit 7. The vaporization unit 19 in this case replaces the coolant water condensation unit 20 from FIG. 1 and is used simultaneously as the vaporization unit 19 for the refrigerant of the absorption heat pump 8, which changes its phase from liquid into vapor on the secondary side of the vaporization unit 19, in that it withdraws its heat from the steam flowing in from the steam turbine system 4, until this steam also changes its phase from vapor into liquid on the primary side of the vaporization unit 19.
The outflowing condensate of the working medium is suctioned in the first preferred embodiment by the working medium pump system 6 and transported by means of pressurizing through the working medium pump system 6, in the direction of liquefying unit 15 of the refrigerant circuit 7. In this refrigerant circuit 7, the condensate of the working medium now withdraws the charged thermal energy from the simultaneously operated, superimposed, absorption heat pump process and thus increases its energy content. Subsequently, the working medium thus preheated is suctioned as feed water by means of the further working medium pump system 16 of higher pressure than the above-described working medium pump system 6, pressurized by means of the downstream further working medium pump system 16, and conducted into the steam generator system 14. Due to the above-described preheating of the working medium from the working medium circuit 2 in the liquefying unit 15, the fuel consumption is therefore reduced from the heat energy supply system 24, which supplies the remaining thermal energy until reaching the required total system design heating power of the plant for steam generation. Due to the described preheating by means of reclamation of the vaporization heat from the exhaust steam of the steam turbine system 4, the fuel and/or heat energy consumption, in comparison to conventional processes as described in FIG. 1, is significantly reduced and the efficiency of the novel overall system is increased accordingly. In the steam generator system 14, the liquid working medium now changes its phase from liquid into vapor due to heat supply from the heat energy supply system 24. The vaporized working medium exits from the steam generator system 14 as so-called fresh steam and is guided to the steam turbine system 4.
In the steam turbine system 4, the energy thereof is withdrawn from the fresh steam enough to operate the mechanically coupled working machine system or generator system 26. The useful work performed here is discharged by the generator system 26 to a consumer in the form of useful energy. The exhaust steam from the steam turbine system 4 is returned back to the clockwise part of the overall process, which corresponds to the working medium circuit 2.
The counterclockwise cyclic process by means of absorption heat pump 8, which is simultaneous to, coupled to, and superimposed on this clockwise part of the overall process in regular operation for the first preferred embodiment, now functions as follows. The refrigerant vapor arising in the vaporization unit 19 flows into the absorber system 27 and merges therein with the solvent to form an enriched, strong solution. This is subsequently suctioned by the solvent pump system 28 and pressurized. The strong solution is then supplied to the solution heat exchanger system 29, wherein a first additional thermal energy absorption already takes place therein by exchange with the unsaturated, lean solution draining out of the expeller system 12 via the return line 39. The strong solution of higher energy which is thus preheated flows into the expeller system 12, where the refrigerant in solution is thermally expelled with the aid of supplied heat from the expulsion line 9. The remaining lean solution is, as already described, discharged via the return line 39, exchanges its thermal energy in the solution heat exchanger system 29 as much as possible with the rich solution and is supplied to a solvent throttle system 31. This solvent throttle system 31 now throttles the lean solution and discharges it via the return line 39 further in the direction of the absorber system 27 sufficiently that it can again merge with the refrigerant vapor to form a strong solution. The refrigerant vapor released in the expeller system 12 is conducted to the liquefying unit 15. In this liquefying unit 15, the refrigerant vapor exchanges its thermal energy content with the condensate of the working medium of the working medium circuit 2 until it condenses. Subsequently, the refrigerant condensate is conducted to a refrigerant throttle system 30, which in turn throttles the inflowing refrigerant condensate enough that it is then supplied to the vaporization unit 19, again reaches its thermal state variables as at the starting point in time of the system passage, whereby the counterclockwise cyclic process of the refrigerant circuit 7 is closed in that it can be vaporized again. The superimposed counterclockwise process then begins again with the vaporization of the refrigerant under supply of thermal energy from the exhaust steam of the steam turbine system 4.
To provide the required thermal energy for the thermal expulsion of the refrigerant in the expeller system 12, in regular operation, a withdrawal of the hot steam from a turbine extraction point 11 from the steam turbine system 4 is provided. In addition, the component of the water steam of the overall system generated in the steam generator system 14 required for this purpose can be branched off from the fresh steam line 25 to the steam turbine system 4. A system-external steam supply is also an implementable option, but is not explicitly shown here. All three or also both illustrated variants can also be implemented simultaneously for reasons of redundancy.
The first backflow safeguard system 34 can be provided at the turbine extraction point 11, so that the steam of the steam generator system 14 cannot flow because of its higher pressure via the turbine extraction point 11 into the steam turbine system 4.
The withdrawn hot steam for operating the expeller system 12 is supplied thereto, changes its phase in the expeller system 12 from vapor to liquid, and is subsequently recirculated as condensate into the working medium circuit 2. The advantage of the turbine extraction point 11 is that the fresh steam, which is of higher value from a thermodynamic viewpoint, can be used until reaching the extraction parameters at the turbine extraction point 11 or making the energy usable by means of working machine and/or generator system 26. The overall efficiency of the overall plant is thus significantly improved.
The turbine extraction point 11 is to be designed so that withdrawn steam has a sufficiently high energy content to operate the expeller system 12 and the condensate arising in the expeller system 12 can be supplied back to the working medium circuit 2 via the feed point 13. In the design of the turbine extraction point 11, it is to be taken into consideration that the withdrawn steam enables the supply of the expeller system 12 from full load operation until reaching the minimum load of the steam turbine system 4. An absolute pressure greater than 1 [bar_abs] is preferably provided here. The maximum pressure at the turbine extraction point 11 is to be designed so that the energy content of the steam is sufficient for the operation of the expeller system 12 and the condensate can be recirculated as previously described.
In particular, it can be provided that the absolute pressure at the turbine extraction point 11 is less by at least 5%, preferably 10%, particularly preferably 15% than an intake pressure of the fresh steam from the fresh steam line 25 at the steam turbine system 4.
In order to be able to start up or shut down the steam power plant 1, even before reaching the required fresh steam parameters in the fresh steam line 25, which enables the initiation of the steam turbine system 4, or upon the shutdown of the steam turbine system 4, or in cases of malfunction, the fresh steam can be discarded via an outlet valve 37, or can be conducted via the bypass line 18 by means of the predefinably blockable bypass valve 35 to the second heat exchanger 5. If the bypass line 18 is used, the second backflow safeguard system 36 is preferably provided, so that no steam can flow backwards into the steam turbine system 4. In regular operation, the bypass line 18 remains closed. As long as steam is discarded via the outlet valve 37, the discarded steam quantity is to be replaced in the same quantity from an external process water supply 38. A parallel operation of the outlet valve 37 for discarding the fresh steam and the bypass line 18 is possible and is provided for the startup and shutdown of the steam power plant 1.
During the operation of the bypass line 18, the introduced heat can be dissipated in the second heat exchanger system 5 by the operation of the refrigerant circuit 7, wherein the expulsion line 9 is supplied via the open fresh steam extraction valve 33.
By way of the present first preferred embodiment of the steam power plant 1 as a superposition of a clockwise with a counterclockwise cyclic process, a novel overall process thus results, the efficiency of which is significantly greater than that from FIG. 1. The use of the absorption heat pump 8 in comparison to a compression heat pump offers the advantage that larger material flows can be transferred in a technically simply implementable manner. In addition, in this first embodiment, the coolant water condensation unit 20 from FIG. 1 is completely replaced.
It can furthermore preferably be provided that the second heat exchanger system 5 has a coolant water condensation unit 20 of the working medium circuit 2. This is shown by way of example in the second preferred embodiment in FIG. 4. In this case, the second heat exchanger system 5 can in particular contain both a vaporization unit 19 and also the coolant water condensation unit 20. The absorption heat pump 8 can thus be embodied smaller with respect to the capacity, and/or the steam power plant 1 can better carry out load changes, since rapidly occurring condensation heat can be dissipated easily via the coolant water.
It can be provided in this case that the vaporization unit 19 and the coolant water condensation unit 20 are designed as essentially of equal size with respect to the heat exchange capacity. In case of malfunction, a complete redundancy can thus be ensured.
Furthermore, it can be provided that the heat exchange capacity of the coolant water condensation unit 20 is only designed as large enough that it is sufficient for the startup operation. It can thus be ensured that the condensation heat can be dissipated in the startup operation, while it is at least primarily dissipated in regular operation via the vaporization unit 19.
It can preferably be provided that the working medium circuit 2 in the second heat exchanger system 5 leads in parallel through the vaporization unit 19 of the refrigerant circuit 7 and the coolant water condensation unit 20. In this case, the working medium circuit 2 can divide after the steam turbine system 4 into multiple lines, which lead in parallel through the vaporization unit 19 and the coolant water condensation unit 20, wherein the working medium circuit 2 can subsequently be brought together again. The working medium of the working medium circuit 2 can thus divide into multiple lines after the steam turbine system 4, wherein the parallel through-flow of the steam from the working medium circuit 2 through the vaporization unit 19 and the coolant water condensation unit 20 is ensured, wherein the working medium circuit 2 is subsequently brought together again after the exit from the vaporization unit 19 and the coolant water condensation unit 20. In this case, the vaporization unit 19 and the coolant water condensation unit 20 can each be designed as separate heat exchangers which are specially optimized for the heat transfer to the refrigerant or coolant, whereby these heat exchangers can be optimized with respect to material selection, flow resistance, and heat transfer. Furthermore, the absorption heat pump 8 is thus integratable easily into existing plants. Furthermore, in the case of the parallel arrangement and/or steam inflow from the working medium circuit 2 into the vaporization unit 19 and the coolant water condensation unit 20, the entry enthalpy is equal, so that the effectivity of the refrigerant circuit 7 can be optimized as a whole.
Furthermore, it can be provided that the second heat exchanger system 5 has a valve system 21 for the predefinable division of a working medium flow between the vaporization unit 19 and the coolant water condensation unit 20 arranged in parallel. The heat quantity to be emitted to condense the working medium in the second heat exchanger system 5 can thus be divided in a targeted manner between the absorption heat pump 8 and the coolant water condensation unit 20, whereby the steam power plant 1 can change the output without problems and the absorption heat pump 8 can be operated in the optimum parameter range.
In the second preferred embodiment in FIG. 4, as described above, in contrast to FIG. 3, the coolant water condensation unit 20 provided in FIG. 1 remains and the exhaust steam of the steam turbine system 4 is divided using the valve system 21 in accordance with the overall system design, so that in each case a part of this waste heat of the vaporization unit 19 is available for heat emission to the refrigerant and/or a part of the waste heat is supplied to the coolant water condensation unit 20 and is dissipated by means of coolant medium through the coolant water recirculation line 22 to the surroundings. In this case, only the component of the waste heat from the steam turbine system 4 which is transferred in the vaporization unit 19 to the refrigerant is used for the increase of efficiency of the overall system in comparison to the process in FIG. 1 On both sides, the working medium is condensed in the vaporization unit 19 and/or the coolant water condensation unit 20 and after exit of the condensed working medium 2 from the vaporization unit 19 and the coolant water condensation unit 20 it is brought together again and jointly transported further unified in the clockwise cyclic process part of the overall system. All further system functions of this second preferred embodiment are equivalent to those described in the first preferred embodiment from FIG. 3. If the fresh steam is to be conducted via the bypass line 18 into the vaporization unit 19, the functionality is thus as described in FIG. 3. In addition to FIG. 3, the fresh steam can also be discharged via the bypass line 18 directly to the coolant water condensation unit 20, which improves the operational flexibility of the steam power plant 1 and increases its availability. The illustrated arrangement is used, inter alia, in comparison to FIG. 3, for simpler integration into already existing systems and is to be understood as a partial superposition of counterclockwise and clockwise cyclic processes using an absorption heat pump process. It is also used to more strongly incorporate financially or locally provided aspects of existing plants or also in new projects into the design of the steam power plant 1.
Alternatively, it can be provided that a coolant water recirculation line 22 leading out of coolant water condensation unit 20 leads through the vaporization unit 19 of the refrigerant circuit 7. In this case, a heat exchange does not take place between the working medium circuit 2 and the refrigerant circuit 7 in the second heat exchanger system 5 directly via a heat exchanger, but rather via the coolant water as a carrier medium. This has the advantage that in an existing steam power plant 1, the working medium circuit 2 in the second heat exchanger system 5 can remain unchanged, whereby retrofitting is possible particularly simply.
FIG. 5 shows, in a form illustrated as a process diagram, a third preferred embodiment of the steam power plant 1. In this case, the existing vaporization unit 19 remains in place as in FIG. 4 and the vaporization heat of the refrigerant is withdrawn from the coolant water recirculation line 22 of the coolant water condensation unit 20. The remaining process is equivalent to that in FIG. 3, wherein no division of the exhaust vapor flow as in FIG. 4 is required. The valve system 21 from FIG. 4 is therefore omitted. Because of the low temperatures of the coolant water, the thermodynamic design is the least productive with respect to the overall efficiency in this case in comparison to the other preferred exemplary embodiments in FIG. 3 and FIG. 4.
Furthermore, it can be provided that a further refrigerant circuit 23 at least partially comprises the first heat exchanger system 3 and at least partially comprises the second heat exchanger system 5, wherein in particular the further refrigerant circuit 23 corresponds in the structure to the refrigerant circuit 7. The absorption heat pump 8 can then have multiple refrigerant circuits 7, 23 operating in parallel, which can be switched in depending on demand and load. A steam power plant which reacts very flexibly to output changes can thus be achieved. For reasons of design, production, and costs, the counterclockwise absorption heat pump cyclic process can then be divided onto multiple refrigerant circuits 7, 23 to be operated in parallel.
FIG. 6 shows by way of example, in a form illustrated as a process diagram, a fourth preferred embodiment of the steam power plant 1. In this case, a steam power plant 1 according to FIG. 3 having two counterclockwise absorption heat pump processes operated in parallel is illustrated, which each have a separate refrigerant circuit 7, 23. Furthermore, still further parallel arrangements having three, four, or even more refrigerant circuits 7, 23 can also be provided, which simultaneously ensure the heat loss displacement. In this case, in each of these parallel processes, the component of the heat loss is displaced from the clockwise cyclic process part of the working medium circuit 2 which corresponds to the design of the refrigerant circuit 7, 23. This multiple arrangement operated in parallel is sensible to optimize the overall plant for greater part load capability, while simultaneously obtaining redundancy with respect to the availability of the overall system.
For reasons of design, production, and cost, the counterclockwise absorption heat pump cyclic process part of the overall system can also be divided in the preferred embodiments according to FIGS. 4 and 5 onto multiple refrigerant circuits 7, 23 to be operated in parallel, as shown in FIG. 6 for FIG. 3. In this case, in each of these parallel processes, the component of the heat loss is displaced from the clockwise cyclic process part which corresponds to the design of the respective refrigerant circuit 7, 23.
In this case, the individual designs of the second heat exchanger system 5 of the different preferred embodiments can be combined with one another to combine the advantages of the individual preferred exemplary embodiments. It can preferably be provided, for example, that the preferred embodiment in FIG. 6 is additionally designed having a coolant water condensation unit 20, which is operated according to the second or the third preferred embodiment.

Claims

1.-15. (canceled)

16. A steam power plant, comprising:

a working medium circuit for circulation of a working medium, said working medium circuit, when viewed in a flow direction of the working medium, including a first heat exchanger system configured to vaporize the working medium, a steam turbine system having a turbine extraction point, a second heat exchanger system configured to condense the working medium, and a working medium pump system configured to feed the working medium condensed in the second heat exchanger system into the first heat exchanger system;

an absorption heat pump including an expeller system and a refrigerant circuit, said refrigerant circuit configured to at least partially comprise the first heat exchanger system and to at least partially comprise the second heat exchanger system, said absorption heat pump configured to transfer thermal energy from the second heat exchanger system to the first heat exchanger system; and

an expulsion line leading from the turbine extraction point of the steam turbine system via the expeller system of the absorption heat pump to a feed point in the working medium circuit, with the working medium in the expulsion line providing thermal energy for an expulsion process of the absorption heat pump.

17. The steam power plant of claim 16, wherein the first heat exchanger system includes a steam generator system of the working medium circuit and a liquefying unit of the refrigerant circuit, said liquefying unit being configured as a heat exchanger between the working medium circuit and the refrigerant circuit.

18. The steam power plant of claim 17, wherein the feed point of the expulsion line is arranged in the working medium circuit between the steam generator system and the liquefying unit.

19. The steam power plant of claim 17, further comprising a further working medium pump system arranged between the feed point of the expulsion line in the working medium circuit and the steam generator system.

20. The steam power plant of claim 16, wherein the expulsion line has an inlet side in communication with a predefinably closable fresh steam extraction point which is arranged between the first heat exchanger system and the steam turbine system.

21. The steam power plant of claim 20, wherein the working medium circuit includes a predefinably closable bypass line which leads from the fresh steam extraction point to the second heat exchanger system.

22. The steam power plant of claim 16, wherein the second heat exchanger system includes a vaporization unit of the refrigerant circuit.

23. The steam power plant of claim 16, wherein the second heat exchanger system includes a coolant water condensation unit of the working medium circuit.

24. The steam power plant of claim 23, wherein the second heat exchanger system includes a vaporization unit of the refrigerant circuit, said working medium circuit leading in the second heat exchanger system in parallel through the vaporization unit of the refrigerant circuit and the coolant water condensation unit.

25. The steam power plant of claim 24, wherein the second heat exchanger system includes a valve system for dividing a flow of the working medium flow between the vaporization unit and the coolant water condensation unit which is arranged in parallel.

26. The steam power plant of claim 24, further comprising a coolant water recirculation line extending from the coolant water condensation unit and leading through the vaporization unit of the refrigerant circuit.

27. The steam power plant of claim 16, further comprising a further refrigerant circuit configured to at least partially comprise the first heat exchanger system and to at least partially comprise the second heat exchanger system, wherein in particular the further refrigerant circuit has a structure which corresponds to a structure of the refrigerant circuit.

28. A method for operating a steam power plant in regular operation, said method comprising:

vaporizing in a first heat exchanger system a working medium in a working medium circuit;

supplying the vaporized working medium to a steam turbine system;

condensing the working medium downstream of the steam turbine system in a second heat exchanger system;

supplying the condensed working medium back to the first heat exchanger system with the assistance of a working medium pump system;

transferring thermal energy with the assistance of a refrigerant circuit of an absorption heat pump from the second heat exchanger system to the first heat exchanger system;

branching a part of the working medium at a turbine extraction point from the steam turbine system into an expulsion line;

liquefying the part of the working medium in an expeller system of the absorption heat pump; and

returning the liquefied part of the working medium at a feed point back into the working medium circuit

wherein thermal energy for an expulsion process of the absorption heat pump is provided by said part of the working medium.

29. The method of claim 28, further comprising guiding the working medium in a startup operation and/or shutdown operation of the steam power plant past the steam turbine system to the second heat exchanger system and/or the expeller system of the absorption heat pump.

30. The method of claim 28, further comprising discharging at least part of the vaporized working medium via an outlet valve to the surroundings, until reaching provided steam parameters of the vaporized working medium or in case of malfunction, wherein in particular a mass flow, which is discharged via the outlet valve, of working medium from the working medium circuit is compensated for via an external process water supply.