JP2013100726A - Residual heat low boiling point electric power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a residual heat low boiling point electric power generation system capable of performing condensing process of a steam power generation system and a process for using residual heat in a well-balanced manner, while significantly increasing efficiency of energy of the entire system including the steam power generation system with a simple structure.SOLUTION: A low boiling point heat cycle is formed, which includes a heat exchanger 22 performing heat exchange by separating and introducing some of residual heat steam discharged from a steam turbine ST from a pipe passage from a steam turbine ST outlet to a low pressure condenser 15 in a steam power generation system 10 and a low boiling point medium turbine T using a low boiling point medium as compared with water and driving an electric power generator by the low boiling point medium heated via the heat exchanger 22, and is connected to the steam power generation system 10.

Description

  The present invention is a residual heat low-boiling point power generation system capable of performing a condensate process and a residual heat utilization process of a steam power generation system in a well-balanced manner with a simple configuration while significantly improving the energy efficiency of the entire system including the steam power generation system It is about.

  Conventionally, incinerators such as sludge have been using heat from exhaust gas from the incinerator as a heat source, and various devices such as a steam power generation device and a white smoke prevention device have been installed to effectively use the exhaust heat.

  Here, in Patent Document 1, a mixed medium having a steam system having a steam turbine driven by steam using nuclear power as a heat source and a mixed medium turbine driven by a gaseous mixed medium heated by the exhaust of the steam turbine. A power plant with a system is described.

Japanese Patent Laid-Open No. 11-257025

  By the way, the residual heat of the steam output from the steam turbine of the steam power generator attached to the incinerator described above is discarded by a condenser or the like, which hinders improvement in energy efficiency of the entire incineration system. It was.

  Further, an extra energy is required to drive a cooler, a cooling pump, and the like for cooling the residual heat of the water vapor in a condenser and the like, and further improvement in energy efficiency of the entire incineration system is desired.

  In addition, although it is not described in detail in the prior art document 1, what integrates a condenser and a heat exchange function is described. In this case, in the configuration of the integrated condenser, since it is considered that heat exchange of all the remaining heat steam is performed, the power generation capacity of the steam power generation apparatus and the power generation capacity of the power generation apparatus that generates power via the heat exchange apparatus In some cases, it is difficult to distribute the high-temperature steam condensate treatment and the residual heat utilization treatment in a well-balanced manner according to the power generation state of the steam power generation apparatus.

  The present invention has been made in view of the above, and with a simple configuration, while significantly improving the energy efficiency of the entire system including the steam power generation system, the condensate process of the steam power generation system and the residual heat utilization process are performed. An object of the present invention is to provide a residual heat low boiling point power generation system that can be performed in a well-balanced manner.

  In order to solve the above-described problems and achieve the object, a residual heat low boiling point power generation system according to the present invention is discharged from a steam power generation turbine outlet to a condenser in a steam power generation system. A heat exchanger that separates and introduces a portion of the residual heat steam and performs heat exchange, and a low-boiling medium that has a lower boiling point than water and that drives the generator with the low-boiling medium heated through the heat exchanger. A low-boiling point heat cycle including a boiling point power generation turbine is formed and connected to the steam power generation system.

  Further, the residual heat low boiling point power generation system according to the present invention, in the above invention, adjusts the distribution of the water vapor flow rate from the pipe line to the condenser side and the water vapor flow rate from the pipe line to the heat exchanger side. It is characterized by having a regulating valve for performing.

  The residual heat low-boiling point power generation system according to the present invention performs heat exchange by introducing high-temperature wastewater discharged from a flue gas treatment device that cools exhaust gas from a heat source of the external steam power generation system in the above-described invention. A high-temperature waste water heat exchange device is provided on the low boiling point heat cycle.

  The remaining heat low boiling point power generation system according to the present invention is the above invention, wherein a part of the steam is extracted from the low pressure steam sump of the external steam power generation system, and the low boiling point power generation system is on the low boiling point heat cycle. The low-pressure steam heat exchange device provided in the front stage of the turbine performs heat exchange between the extracted steam and the low boiling steam, and sends the low boiling steam to the low boiling power turbine as superheated steam. Features.

  In the remaining heat low boiling point power generation system according to the present invention as set forth in the invention described above, the low boiling point heat cycle is a Rankine cycle using the low boiling point medium.

  In the remaining heat low boiling point power generation system according to the present invention as set forth in the invention described above, the low boiling point thermal cycle is a carina cycle using a mixed medium of the low boiling point medium and water.

  According to the present invention, a heat exchange device that performs heat exchange by separating and introducing a part of the remaining steam discharged from the steam power generation turbine from a pipeline from the steam power generation turbine outlet to the condenser in the steam power generation system, A low-boiling point heat cycle comprising a low-boiling point power cycle using a medium having a lower boiling point than water vapor and driving a generator with the low-boiling point medium heated via the heat exchange device, Since it is cascade-connected to the system, the condensate treatment of the steam power generation system and the residual heat utilization treatment can be performed in a well-balanced manner with a simple configuration while significantly improving the energy efficiency of the entire system including the steam power generation system. .

FIG. 1 is a block diagram showing a configuration of an incineration system including a residual heat power generation system according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing a configuration of an incineration system including a residual heat power generation system according to Embodiment 2 of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of an incineration system including a residual heat power generation system according to Embodiment 1 of the present invention. As shown in FIG. 1, the incineration system 1 includes an incinerator 2, a boiler 3, a dust collector 4, a flue gas treatment tower 5, a steam power generation system 10, and a residual heat low boiling point power generation system 20.

  The incinerator 2 incinerates an incineration object such as sludge, and incinerates the incineration object using air supplied from the blower 6 and fuel supplied as necessary, for example, about 850 ° C. Is output to the boiler 3 as a high-temperature combustion gas. The incinerator 2 is realized by a fluidized incinerator or a circulating incinerator, but may be realized by other incineration methods.

  The boiler 3 serves as a heat source for the steam power generation system 10. The dust collector 4 collects and removes the combustion ash from the combustion gas of the combustion furnace 2 sent through the boiler 3, and sends the combustion gas from which the combustion ash has been removed to the flue gas treatment tower 5. In addition, the temperature of the combustion gas sent from the boiler 3 is about 250-300 degreeC, for example. The flue gas treatment tower 5 supplies normal temperature water, lowers the temperature of the combustion gas sent from the dust collector 4 to, for example, about 40 to 50 ° C., and blows the combustion gas from a chimney (not shown) via the blower 7. Release into the atmosphere. The heat of the high temperature waste water out of the water in which the smoke treatment tower is heat-exchanged is used for the residual heat low boiling point power generation system 20.

  The steam power generation system 10 is a system that generates electricity by driving the steam turbine ST by a Rankine cycle using water as a medium, using the combustion gas of the boiler 3 as a heat source, and driving a generator 14 coupled to the steam turbine ST. .

  The boiler 3 heats the circulating water to convert it into water vapor, and the converted high-temperature and high-pressure water vapor is input to the steam header 11. The steam header 11 is a steam header, temporarily accumulates water vapor from the boiler 3, and distributes it to each pipe. Although a plurality of pipes are not shown in FIG. 1, pipes that supply water vapor to a system other than the water vapor power generation system 10 are combined.

  Water vapor is supplied from the steam header 11 to the high-pressure steam sump 12. The high-pressure steam sump 12 corresponds to the work of the steam turbine ST, supplies necessary steam to the steam turbine ST to drive the steam turbine ST, and sends surplus steam to the high-pressure condenser 13 to supply steam. to keep balance. For example, the high-pressure steam sump 12 is provided on the high-pressure condenser 13 side when the steam turbine ST is in a low load state or when more steam than the steam amount required by the steam turbine ST is supplied from the boiler 3 side. Return water vapor to

  The steam turbine ST is driven when high-temperature and high-pressure steam supplied from the high-pressure steam sump 12 is input to the inlet, and drives the generator 14 to generate power. Worked low-temperature and low-pressure steam (preheated steam) is discharged from the outlet of the steam turbine ST. This residual heat steam is input to the low-pressure condenser 15 through the regulating valve 10a, but a part of the residual heat steam is provided along with the regulating valve 10a in the middle of the piping branched from the steam turbine ST side of the regulating valve 10a. The control valve 10b and the control valve 10c provided in the middle of the piping that joins from the low pressure condenser 15 side of the control valve 10a are supplied to the heat exchange device 22 of the residual heat low boiling point power generation system 10. The three regulating valves 10a to 10c are flow regulating valves, and distribute the flow rate of the residual heat steam discharged from the steam turbine ST outlet to the low pressure condenser 15 side and the residual heat low boiling point power generation system 20 side. For example, when the load of the steam turbine ST is low, the supply flow rate to the residual heat low boiling point power generation system 20 side is increased so that stable power generation of the residual heat low boiling point power generation system 20 can be performed.

  The low-pressure condenser 15 reduces the temperature of the residual heat steam by the cooling water generated by the cooling pump 15a and the cooling device 15b and condenses them. By this condensation, the outlet side of the steam turbine ST becomes a negative pressure state, and the conversion efficiency of the steam turbine ST can be increased.

  Here, the heat exchange of the preheated steam circulating through the regulating valves 10b and 10c is also performed by the heat exchange device 22, and the temperature of the preheated steam is lowered. For this reason, the condensing capacity of the low-pressure condenser 15 is smaller than that of the conventional one, and the configuration of the low-pressure condenser 15 can be simplified. Further, the cooling capacity and configuration of the cooling pump 15a and the cooler 15b can be small. In addition, it is possible to reduce the amount of residual heat that was discarded in the low-pressure condenser 15, and to use a part of the residual heat that was discarded in the conventional low-pressure condenser 15 in the residual heat low-boiling point power generation system. That is, a part of the heat energy discarded in the conventional low-pressure condenser 15 can be effectively used in the residual heat low-boiling point power generation system 20, and the cooling pump 15 a that realizes the condensing capacity of the low-pressure condenser 15. Since the driving energy of 15b is reduced, the energy efficiency of the entire system is synergistically improved. Furthermore, even when the remaining heat steam output from the steam turbine ST of the steam power generation system 10 is in a relatively high temperature state, the flow rate of the remaining heat steam to the low pressure condenser 15 side and the flow rate to the heat exchange device 22 side. Therefore, the condensate treatment of the remaining heat steam and the utilization processing of the remaining heat can be performed in a well-balanced manner.

  The condensate tank 16 stores the water supplied from the low-pressure condenser 15 and the water supplied from the high-pressure condenser 13 via the pump 16a, and is sent to the deaerator 17 via the pump 16b. The The pressure balance in the condensate tank 16 is achieved by controlling the driving of the pumps 16a and 16b.

  The deaerator 17 further heats the input condensate to remove air such as oxygen dissolved in the water. When the deaerator 17 removes air, corrosion of the boiler 3 and piping can be prevented. The decompression and temperature reduction device 18 decompresses and reduces the water vapor stored in the high-pressure steam sump 12 and stores it in the low-pressure steam sump 19. The deaerator 17 heats the steam using the low-pressure steam sump 19. Then, the water dissolved in water is removed by once volatilizing and recondensing the water. The degassed water is supplied again to the boiler 3 and circulates through the Rankine cycle of the steam power generation system 10.

  On the other hand, the residual heat low boiling point power generation system 20 is a system cascade-connected to the steam power generation system 10 described above, and drives the low boiling point medium turbine T by a Rankine cycle using a medium having a boiling point lower than that of water. This is a system for generating electricity by driving a generator 23 coupled to a medium turbine T. The reason why the low boiling point medium is used is that high-pressure steam can be easily obtained with a low-temperature heat source called residual heat steam. This low boiling point medium is, for example, ammonia or alternative chlorofluorocarbon. Ammonia is a colorless and transparent low-boiling medium that naturally exists in nature, and its evaporation temperature is -33.3 ° C., 4.0 MPa, 79.6 ° C. under air, and has good thermophysical properties. The global warming potential is zero and the ozone depletion potential is zero.

  The residual heat low boiling point power generation system 20 includes a heat exchange device 22 that performs heat exchange between residual heat steam supplied from the steam power generation system 10 side and a medium having a lower boiling point than water. In addition, a heat exchange device 21 that performs heat exchange between the high-temperature wastewater supplied from the flue gas treatment tower 5 and the low-boiling point medium may be disposed in the front stage of the heat exchange device 22. By using the high temperature waste water supplied from the smoke treatment tower 5, the energy efficiency of the entire incineration system 1 can be further increased.

  Ammonia, which is a low-boiling point medium supplied by the pump 25, easily becomes ammonia vapor via the heat exchange devices 21 and 22, and this high-pressure ammonia vapor is supplied to the inlet of the low-boiling point turbine T to generate a generator. The work which drives 23 is performed. The worked ammonia vapor is discharged from the outlet of the low-boiling-point medium turbine T, is input to the condenser 24, is converted into ammonia liquid, and is circulated through the pump 25.

  Further, by introducing the steam extracted from the low-pressure steam sump 19 to the steam heater 35, the low-boiling-point medium steam can be superheated and the efficiency can be improved.

  In the first embodiment, the residual heat low boiling point power generation system 20 is cascade-connected to the steam power generation system 10, and a part of the residual heat steam discharged by the steam turbine ST from the pipe line from the outlet of the steam turbine ST to the low pressure condenser 15 is obtained. Since heat exchange is performed by separating and introducing heat, the thermal energy discarded by the steam power generation system 10 can be used effectively, and the configurations and capacities of the low-pressure condenser 15, the cooling pump 15a, and the cooler 15b can be increased. Since it can be made small and the energy used can be reduced, the energy efficiency of the entire incineration system 1 can be remarkably improved. Moreover, since the residual heat low-boiling point power generation system 20 generates power using a low-boiling point medium, it can be easily vaporized even when using the residual heat steam with a small thermal energy. Power generation. Furthermore, even when the residual heat steam output from the steam turbine of the steam power generation system is in a relatively high temperature state, the flow rate of the residual heat steam to the low-pressure condenser 15 side and the flow rate to the heat exchange device 22 side are determined. Since it can adjust, the condensate process of residual heat steam and the utilization process of residual heat can be performed with good balance.

(Embodiment 2)
In the first embodiment described above, the residual heat low boiling point power generation system 20 constitutes a Rankine cycle using ammonia, but in this second embodiment, the residual heat low boiling point power generation system corresponding to the residual heat low boiling point power generation system 20. The system 30 constitutes a carina cycle using a mixed medium of ammonia and water, which is an example of a mixed medium of a low boiling point medium and water.

  FIG. 2 is a block diagram showing a configuration of an incineration system including a residual heat power generation system according to Embodiment 2 of the present invention. As shown in FIG. 2, in the residual heat power generation system 30 of the incineration system 101, in addition to the configuration of the residual heat power generation system 20, a gas-liquid separator 31 is provided between the heat exchange device 22 and the low boiling point medium turbine T. The regenerator 32 is provided between the pump 25 and the heat exchange device 21, the absorber 34 is provided between the low boiling point medium turbine T and the condenser 24, and the pressure reducing valve 33 is provided with the regenerator 32 and the absorber 34. Between.

  The Carina cycle uses a mixed medium of ammonia and water as a low boiling point medium, and performs efficient heat recovery by non-isothermal evaporation and non-isothermal condensation (absorption) in the process of evaporation and condensation, respectively. It is.

  The gas-liquid separator 31 separates the mixed medium input from the heat exchange device 22 into high-concentration ammonia vapor and low-concentration ammonia water that cannot be completely evaporated by the heat exchange device 22. The high-concentration ammonia vapor in a high pressure state is sent to the low boiling point medium turbine T, and drives the low boiling point medium turbine T as in the Rankine cycle. On the other hand, the low-concentration aqueous ammonia is sent to the regenerator 32 that is a heat exchange device, and the low-concentration aqueous ammonia that has been cooled by the heat exchange with the mixed medium circulated from the pump 25 is absorbed through the pressure reducing valve 33. Sent to.

  In the absorber 34, the high-concentration ammonia vapor discharged from the low-boiling-point medium turbine T outlet and the low-concentration ammonia water input via the pressure reducing valve 33 are merged, and in the absorber 34, the high-concentration ammonia vapor is It is condensed and absorbed all at once by the cooled and decompressed low concentration ammonia water. By this absorption, the exhaust of the low boiling point medium turbine T can be set to a negative pressure, and the turbine output can be improved. Further, by introducing the steam extracted from the low-pressure steam sump 19 to the steam heater 35, the low boiling point medium steam can be superheated, and the efficiency can be further improved.

  In the second embodiment, since the residual heat low boiling point power generation system forms a carina cycle using a mixed medium of low boiling point and water, the energy efficiency can be further increased as compared with the first embodiment.

DESCRIPTION OF SYMBOLS 1,101 Incineration system 2 Incinerator 3 Boiler 4 Dust collector 5 Smoke treatment tower 6,7 Blower 10 Steam power generation system 10a-10c Regulating valve 11 Steam header 12 High-pressure steam sump 13 High-pressure condenser 14, 23 Generator 15 Low-pressure condenser 15a Cooling pump 15b Cooler 16 Condensate tank 16a, 16b Pump 17 Deaerator 18 Depressurization and temperature reduction device 19 Low-pressure steam sump 20, 30 Residual heat low boiling point power generation system 21, 22 Heat exchanger 24 Condenser 25 Pump 31 Gas-liquid separator 32 Regenerator 33 Pressure reducing valve 34 Absorber 35 Steam heater ST Steam turbine T Low boiling point medium turbine

Claims (6)

A heat exchange device that separates and introduces a portion of the remaining steam discharged from the steam power generation turbine from a pipeline from the steam power generation turbine outlet to the condenser in the steam power generation system, and performs heat exchange;
A low-boiling-point power generation turbine that uses a medium having a lower boiling point than water and drives a generator by the low-boiling point medium heated through the heat exchange device;
A residual heat low boiling point power generation system, characterized in that a low boiling point heat cycle comprising: is formed and connected to the steam power generation system.   2. The residual heat according to claim 1, further comprising an adjustment valve that performs distribution adjustment between a water vapor flow rate from the pipe line to the condenser side and a water vapor flow rate from the pipe line to the heat exchange device side. Low boiling point power generation system.   A high-temperature wastewater heat exchange device that performs heat exchange by introducing high-temperature wastewater discharged by a smoke treatment device that cools exhaust gas from a heat source of the external steam power generation system is provided on the low-boiling-point heat cycle. The residual heat low boiling point power generation system according to claim 1 or 2, characterized in that   A portion of the steam is extracted from the low-pressure steam reservoir of the external steam power generation system, and the extracted steam is extracted by a low-pressure steam heat exchange device provided on the low-boiling point heat cycle and before the low-boiling point power generation turbine. The low-boiling point steam is sent to the low-boiling-point power generation turbine as superheated steam by performing heat exchange between the low-boiling point steam and the low-boiling point steam. Boiling point power generation system.   The residual heat low boiling point power generation system according to any one of claims 1 to 4, wherein the low boiling point thermal cycle is a Rankine cycle using the low boiling point medium.   The residual heat low boiling point power generation system according to any one of claims 1 to 4, wherein the low boiling point heat cycle is a carina cycle using a mixed medium of the low boiling point medium and water.

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