JP5205365B2 - Fossil fuel fired thermal power generation system equipped with carbon dioxide separation and recovery device - Google Patents

Description

  The present invention relates to a fossil fuel-fired thermal power generation system including a carbon dioxide separation and recovery device.

As a fossil fuel-fired thermal power generation system equipped with a carbon dioxide separation and recovery device according to the present invention, a high-pressure, medium-pressure, low-pressure turbine, a steam turbine driven by fossil fuel, for example, steam generated by a coal fired boiler, Some have a device (PCC: Post Combustion CO ₂ Capture) for separating and collecting carbon dioxide from exhaust gas generated in the boiler.

  For example, Japanese Patent No. 4274848 discloses a fossil fuel-fired thermal power generation system equipped with a carbon dioxide separation and recovery device for generating a steam turbine having a high-pressure turbine, an intermediate-pressure turbine and a low-pressure turbine, and steam for driving them. Boiler, a carbon dioxide absorption tower having a carbon dioxide absorption liquid for absorbing and removing carbon dioxide from the combustion exhaust gas of the boiler, and a regeneration tower for regenerating the carbon dioxide absorption liquid that has absorbed carbon dioxide are removed. A compressor for compressing the carbon dioxide, a compressor turbine driven by a part of the exhaust steam of the high pressure turbine, an auxiliary turbine driven by a part of the exhaust steam of the intermediate pressure turbine, a compressor turbine, A supply pipe for supplying the exhaust steam of the auxiliary turbine to the reboiler of the regeneration tower as a heating source; System having is disclosed.

  Generally, in a carbon dioxide recovery device that recovers carbon dioxide from boiler exhaust gas, the absorption liquid is circulated between the absorption tower and the regeneration tower by driving the absorption liquid circulation pump, and is contained in the boiler exhaust gas in the absorption tower. The absorbed carbon dioxide is absorbed in the absorption liquid, and the carbon dioxide absorbed in the absorption liquid is separated and recovered by the regeneration tower.

  That is, the carbon dioxide component in the boiler exhaust gas is brought into contact with the absorption liquid in the absorption tower, and the absorption liquid at about 40 ° C. absorbs carbon dioxide through a chemical reaction (exothermic reaction) with the carbon dioxide in the gas.

At this time, the rich absorption liquid rich in carbon dioxide of about 70 ° C. by the chemical reaction between the absorption liquid and carbon dioxide exits the absorption tower, and is then regenerated about 120 ° C. absorption liquid supplied from the regeneration tower ( Heat exchange is performed with a lean absorbent, which is heated to about 110 ° C. and flows again into the absorption tower.

  The rich absorbent after the heat exchange is further heated to about 120 ° C. to 130 ° C. in the regeneration tower to separate carbon dioxide absorbed in the rich absorbent.

  The absorption liquid from which carbon dioxide has been separated in the regeneration tower becomes a lean absorption liquid and is again introduced into the absorption tower to absorb the carbon dioxide in the boiler exhaust gas.

  At this time, in order to heat the absorption liquid in the regeneration tower so that carbon dioxide is separated to become a lean absorption liquid, the reboiler supplying heating steam to the regeneration tower needs to generate a large amount of steam.

Japanese Patent No. 4274646

  In the fossil fuel-fired thermal power generation system provided with the carbon dioxide separation and recovery device described in the above-mentioned Japanese Patent No. 4274646, carbon dioxide is absorbed between the absorption tower and the regeneration tower of the carbon dioxide separation and recovery device for some reason, and When the pump tower that circulates the absorption liquid to be separated trips and the carbon dioxide separation and recovery device stops urgently, it is necessary to quickly stop the supply of the high-pressure turbine of the steam turbine and the exhaust steam of the intermediate-pressure turbine to the reboiler. However, when the supply of exhaust steam from the high-pressure turbine and intermediate-pressure turbine of the steam turbine to the reboiler is stopped urgently, the surplus exhaust steam that has lost its place of flow flows into the low-pressure turbine of the steam turbine. There is a possibility that a large load is applied to the rotor blades of the low-pressure turbine by rapidly exceeding the allowable swallowed steam amount allowed for the blade strength.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fossil fuel-fired thermal power generation system equipped with a carbon dioxide separation and recovery device that uses a part of steam discharged from a steam turbine for a reboiler or reclaimer of the carbon dioxide separation and recovery device. Even when the supply of steam to the reboiler and reclaimer suddenly becomes unnecessary, the load fluctuation of the fossil fuel-fired thermal power generation system is suppressed, stable operation can be continued, and the carbon dioxide separation and recovery device is stopped. An object of the present invention is to provide a fossil fuel-fired thermal power generation system equipped with a carbon dioxide separation and recovery device capable of recovering surplus steam generated thereby and increasing power generation output.

In order to achieve the above object, a fossil comprising a steam turbine apparatus having a boiler that generates steam by burning fossil fuel, a high pressure turbine, an intermediate pressure turbine, a first low pressure turbine, and a condenser. A fuel-fired thermal power generation system,
Absorption liquid in which carbon dioxide is absorbed by circulating the absorption liquid between the absorption tower that absorbs and recovers carbon dioxide contained in the boiler exhaust gas discharged by burning fossil fuel from the boiler, and the absorption tower In a fossil fuel-fired thermal power generation system equipped with a carbon dioxide separation and recovery device comprising a regeneration tower for absorbing liquid from which oxygen dioxide is separated from, and a carbon dioxide separation and recovery device comprising a reboiler for supplying steam to the regeneration tower, An extraction pipe for supplying extracted steam extracted from the exhaust steam of the steam turbine as a heat source to the reboiler, a first steam pipe communicating with the condenser and the extraction pipe, and a second provided separately from the steam turbine device. A low-pressure turbine, a generator that generates electric power using the power of the second low-pressure turbine, an extraction pipe and the second low-pressure turbine, and the extracted steam flowing down the extraction pipe is supplied to the second low-pressure turbine. A second steam line leading to down, the bleed pipe, the first steam pipe, and a second provided to the steam pipe, and a valve for controlling switching a channel extraction steam flows down.

  According to the present invention, in a fossil fuel-fired thermal power generation system equipped with a carbon dioxide separation and recovery device that uses a part of the steam discharged from the steam turbine for a reboiler or reclaimer of the carbon dioxide separation and recovery device, the carbon dioxide separation and recovery device is urgently stopped. However, even when the supply of steam to the reboiler and reclaimer suddenly becomes unnecessary, fluctuations in the load of the fossil fuel-fired thermal power generation system can be suppressed, stable operation can be continued, and the carbon dioxide separation and recovery device must be stopped. The surplus steam generated by the above can be recovered to increase the power generation output.

1 is a schematic system diagram showing a fossil fuel-fired thermal power generation system including a carbon dioxide separation and recovery device according to a first embodiment of the present invention. FIG. 2 is a partial view showing a fossil fuel-fired thermal power generation system in the first embodiment shown in FIG. 1. The schematic system | strain diagram which shows the fossil fuel-fired thermal power generation system provided with the carbon dioxide separation-and-recovery apparatus which is 2nd Example of this invention. FIG. 4 is a partial view showing the fossil fuel-fired thermal power generation system in the first embodiment shown in FIG. 3.

  A fossil fuel-fired thermal power generation system equipped with a carbon dioxide separation and recovery device according to an embodiment of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the equivalent component through each drawing.

  A fossil fuel-fired thermal power generation system equipped with a carbon dioxide separation and recovery device according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a fossil fuel-fired thermal power generation system equipped with a carbon dioxide separation and recovery device according to a first embodiment of the present invention.

  A fossil fuel-fired thermal power generation system 100 constituting the fossil-fuel-fired thermal power generation system including the carbon dioxide separation and recovery apparatus of the first embodiment shown in FIG. 1 is a condensate that is supplied from a condenser by burning fossil fuel. A fossil fuel-fired boiler 1 that heats water and generates high-temperature and high-pressure steam, and a high-pressure turbine 3 that drives the steam generated in the boiler 1 through the main steam pipe 2 from the boiler 1 are provided.

  Steam generated by the high-pressure turbine 3 and depressurized to flow down the high-pressure turbine exhaust pipe 4 is supplied to the boiler 1 and is heated again by the boiler 1 to become reheated steam.

  The fossil fuel-fired thermal power generation system 100 generates a power by an intermediate pressure turbine 6 that drives the reheat steam heated by the boiler 1 through the high temperature reheat steam pipe 5 from the boiler 1 and drives it. The first low-pressure turbine 8 that guides and drives the decompressed steam through the intermediate-pressure turbine exhaust pipe 7 and the first condenser 9 that generates power in the low-pressure turbine 8 to condense the decompressed steam. With.

  The condenser 9 includes a cooling water pipe 10, and condenses the steam by exchanging heat between the steam guided to the condenser 9 and the cooling water flowing in the cooling water pipe. The condensate condensate in the condenser 9 is sent again to the boiler 1 and is sent as steam to the high-pressure turbine 3 to constitute a steam turbine heat cycle.

  The high-pressure turbine 3, the intermediate-pressure turbine 6 and the low-pressure turbine 8 are connected by a turbine rotor 11. A generator 12 is connected to the turbine rotor 11, and the generator 12 is driven by the rotational power of the high-pressure turbine 3, the intermediate-pressure turbine 6 and the low-pressure turbine 8, and the output of the steam turbine is taken out as electric power. Yes.

  In the fossil fuel-fired thermal power generation system 100, a first extraction pipe branched from the intermediate pressure turbine exhaust pipe 7 of the intermediate pressure turbine 6 and extracting and guiding a part of the exhaust steam flowing down the intermediate pressure turbine exhaust pipe 7. 40 and a first bleed pipe 40, and a PCC device air supply pipe for supplying bleed steam flowing down through the first bleed pipe 40 to a reboiler 25 and a reclaimer 26 installed in a carbon dioxide separation and recovery device 200 described later. 41. A stop valve 50 is provided in the PCC device air supply pipe 41.

  The fossil fuel-fired thermal power generation system equipped with the carbon dioxide separation and recovery device of the first embodiment shown in FIG. 1 includes the fossil fuel-fired thermal power generation system 100 and the boiler 1 of the fossil fuel-fired thermal power generation system 100. A carbon dioxide separation and recovery device (PCC device) 200 that separates and recovers carbon dioxide contained in boiler exhaust gas discharged by burning fossil fuel is installed.

  In the carbon dioxide separation and recovery apparatus 200 shown in FIG. 1, boiler exhaust gas containing carbon dioxide discharged from the boiler 1 and branched and supplied from the boiler exhaust gas system 13 flows down through the boiler exhaust gas pipe 14. After being boosted by the boiler exhaust gas booster fan 15 provided in the boiler exhaust gas, the boiler exhaust gas cooler 16 is supplied to the boiler exhaust gas cooler 16 to be cooled, and the boiler exhaust gas cooler 16 is supplied to the absorption tower 17 for absorbing the carbon dioxide gas in the absorption liquid.

  The treatment gas that has been absorbed in the absorption liquid by the absorption tower 17 into the boiler exhaust gas and becomes boiler exhaust gas that does not contain carbon dioxide passes through the absorption tower 17 through the absorption tower outlet boiler exhaust pipe 18 to the chimney 19. It is supplied and discharged from the chimney 19 to the atmosphere.

  Of the boiler exhaust gas containing carbon dioxide supplied from the boiler 1 through the boiler exhaust gas system 13, the boiler exhaust gas not supplied to the absorption tower 17 is provided in the bypass gas pipe 20 that bypasses the carbon dioxide separation and recovery device 200. By opening the bypass butterfly valve 21, the bypass butterfly valve 21 is directly led to the chimney 19 through the bypass gas pipe 20.

  The rich absorption liquid containing a large amount of carbon dioxide by absorbing the carbon dioxide gas contained in the boiler exhaust gas in the absorption tower 17 is provided in the supply path of the absorption liquid for supplying the absorption liquid of the absorption tower 17 to the regeneration tower 22. The pressure is increased by the rich absorbing liquid transfer pump 23, supplied to the absorbing liquid heat exchanger 24 provided in the absorbing liquid supply path, heated by the absorbing liquid heat exchanger 24, and then supplied to the regeneration tower 22.

  The rich absorption liquid supplied from the absorption tower 17 to the regeneration tower 22 is heated by supplying the steam generated by the reboiler 25 and the reclaimer 26 from the reboiler 25 and the reclaimer 26 to the regeneration tower 22, and the regeneration tower 22. The carbon dioxide gas absorbed inside is separated.

  Carbon dioxide separated from the rich absorption liquid inside the regeneration tower 22 by heating with the steam supplied from the reboiler 25 is discharged from the regeneration tower 22 and cooled by an outlet gas cooler 27 provided on the outlet side of the regeneration tower 22. After that, the water contained in the carbon dioxide gas is separated by being supplied to the reflux drum 28 for separating the water. The carbon dioxide gas from which moisture has been separated is supplied from the reflux drum 28 through a carbon dioxide gas exhaust pipe 29 to a carbon dioxide liquefaction storage facility (not shown) and stored.

  Further, the water separated by the reflux drum 28 is pressurized by a reflux drum pump 30 and returned to the regeneration tower 22.

  A part of the absorption liquid in the regeneration tower 22 is extracted through the regeneration tower absorption liquid extraction pipe 31 and branched and supplied to the reboiler 25 and the reclaimer 26, respectively, and the steam turbine of the fossil fuel-fired thermal power generation system 100 is supplied. Heated steam extracted from the cycle, that is, extracted steam extracted from the intermediate pressure turbine 6 is heated by the reboiler 25 supplied as a heat source.

  The reclaimer 26 is a device for purifying the absorbing liquid that uses the extracted steam extracted from the intermediate-pressure turbine 6 as a heat source to heat the absorbing liquid, separates impurities contained in the absorbing liquid, and discharges them outside the system.

  As the heating steam necessary for heating the reboiler 25 and the reclaimer 26, a part of the exhaust steam flowing down the intermediate pressure turbine 6 constituting the fossil fuel-fired thermal power generation system 100 is extracted, and the first extraction pipe 40 and the PCC device are extracted. It is obtained by supplying air to the reboiler 25 and the reclaimer 26 through the air supply pipe 41.

  The absorption liquid obtained by separating carbon dioxide by heating the absorption liquid in the regeneration tower 22 is pressurized by a lean absorption liquid transfer pump 32 provided in the return path of the absorption liquid for returning the absorption liquid from the regeneration tower 22 to the absorption tower 17. Similarly, it is supplied to the lean absorption liquid cooler 33 provided in the return path of the absorption liquid, cooled by the lean absorption liquid cooler 33, and then returned to the absorption tower 17, so that the absorption liquid and the regeneration tower 17 are regenerated. It circulates between the towers 22.

  The carbon dioxide separation and recovery apparatus 200 supplies the extracted steam extracted from the intermediate pressure turbine 6 through the first extraction pipe 40 and the PCC apparatus supply pipe 41 to the reboiler 25 and the reclaimer 26 as a heat source and regenerates from the regeneration tower 22. The absorption liquid extracted through the tower absorption liquid extraction pipe 31 is indirectly heated by the reboiler 25 to generate normal steam at a desired temperature and pressure, and the generated steam is supplied through the reboiler outlet steam pipe 34. It is configured to supply to the regeneration tower 22.

  The PCC device air supply pipe 41 on the upstream side of the reboiler 25 and the reclaimer 26 branches to a reboiler side pipe 35 and a reclaimer side pipe 36, the reboiler side pipe 35 is connected to the reboiler 25, and the reclaimer side pipe 36 is connected to the reclaimer 26. ing. The reboiler side pipe 34 is provided with a flow rate control valve 37, and the reclaimer side pipe 35 is provided with a flow rate control valve 38. The reboiler 25 is configured so that steam generated in the reboiler 25 has a desired temperature and pressure. The flow rate of the extracted steam from the intermediate pressure turbine supplied to the engine is adjusted.

  The fossil fuel-fired thermal power generation system 100 is further installed separately from the second low-pressure turbine air supply pipe 46 branched from the first extraction pipe 40 and the main steam turbine device connected by the turbine rotor 11, The second low-pressure turbine 42 driven by the extracted steam from the intermediate-pressure turbine 6 introduced through the second low-pressure turbine air supply pipe 46, the steam decompressed by driving the second low-pressure turbine 42 are introduced, and the introduced steam and cooling are introduced. A second condenser 45 is provided for heat exchange with the cooling water flowing in the pipe 10 to cool the steam and condense it. The condensate that has been condensed by the second condenser 45 is sent to the boiler 1 again.

  On the inlet side of the second low-pressure turbine 42, a low-pressure turbine inlet control valve 43 that controls the amount of steam flowing into the second low-pressure turbine 42 to control the output of the second low-pressure turbine 42 is provided. In addition, a generator 44 is connected to the second low-pressure turbine 42 so that the power of the second low-pressure turbine 42 is taken out as electric power.

  Further, the fossil fuel-fired thermal power generation system 100 branches from the first extraction pipe 40 upstream from the second low-pressure turbine air supply pipe 46, and the steam flowing down the first extraction pipe 40 flows to the first condenser 9. A condenser condenser pipe 48 is provided.

  The intermediate pressure turbine exhaust pipe 7 is provided with an intermediate pressure turbine exhaust pressure adjustment valve 55 for adjusting the exhaust steam pressure of the intermediate pressure turbine.

  The second low-pressure turbine air supply pipe 38 is provided with a switching valve 47, and the condenser air supply pipe 48 is provided with a switching valve 49.

  FIG. 2 is a partial view showing a part of the fossil fuel-fired thermal power generation system 100 in the fossil fuel-fired thermal power generation system provided with the carbon dioxide separation and recovery device of the first embodiment shown in FIG.

  The fossil fuel-fired thermal power generation system 100 shown in FIG. 2 includes an intermediate pressure turbine exhaust pressure detector 52 that is provided in the intermediate pressure turbine exhaust pipe 7 and detects the intermediate pressure turbine exhaust pressure, and a PCC device air supply pipe 41. An air supply pressure detector 53 that detects the air supply pressure is provided.

  A control device 300 is installed, and the operation of the second low-pressure turbine 42 is controlled by the turbine control device 300. That is, the opening degree of the second low-pressure turbine inlet control valve 43 is adjusted by a command signal from the control device 300 to control the flow rate of the steam supplied to the low-pressure turbine 42.

  By the way, when the main equipment of the carbon dioxide separation and recovery apparatus 200 trips for some reason, for example, the rich absorption liquid transfer pump 23 or the lean absorption liquid transfer pump 31 that transfers the absorption liquid trips and the carbon dioxide separation and recovery apparatus 200 When the operation is urgently stopped, it may be necessary to immediately stop the supply of steam from the fossil fuel-fired thermal power generation system 100 to the carbon dioxide separation and recovery device 200.

  When the supply of steam to the carbon dioxide separation and recovery device 200 is immediately stopped, surplus steam flows into the first low-pressure turbine 8 of the steam turbine through the intermediate-pressure turbine exhaust pipe 7 and the intermediate-pressure turbine exhaust pressure adjustment valve 52. As a result, the amount of steam flowing through the first low-pressure turbine 8 suddenly increases, and the allowable swallowing steam amount allowed for the strength of the turbine blades of the first low-pressure turbine 8 is rapidly exceeded, and the allowable range for the blades of the low-pressure turbine is increased. Excessive load may be applied. As a means for avoiding a sudden load fluctuation of the low-pressure turbine due to such an emergency stop of the carbon dioxide separation and recovery device 200, in the present invention, a second low-pressure turbine is provided, and an emergency escape destination of surplus steam is provided. It is provided.

  The control device 300 provided in the fossil fuel-fired thermal power generation system 100 shown in FIG. 2 controls the operation of the second low-pressure turbine 42 and the extraction steam that flows through the first extraction pipe 40 during the emergency stop of the carbon dioxide separation and recovery device 200. For sequentially switching the supply destination of the carbon dioxide from the carbon dioxide separation and recovery device 200 to the first condenser 9 and the second low-pressure turbine 42.

  When the carbon dioxide separation / recovery device 200 is urgently stopped, for example, the rich absorption liquid transfer pump 23 or the lean absorption liquid transfer pump 32, which is the main device of the carbon dioxide separation / recovery device 200, trips and the carbon dioxide separation / recovery device 200 is operated. When it is necessary to immediately stop the steam supplied to the reboiler 25 from the steam turbine cycle of the fossil fuel-fired thermal power generation system 100, the rich absorbing liquid transfer pump 23 and the lean absorbing liquid transfer pump 32 are respectively connected. A rich absorption liquid transfer pump trip signal 23a or a lean absorption liquid transfer pump trip signal 32a is sent from the installed sensor to the control device.

  As another means for detecting an abnormality in the carbon dioxide separation / recovery device 200, the air supply pressure detector 53 detects a change in the pressure of the steam flowing down in the PCC device air supply pipe 41, and the detector 53 detects the pressure. When an abnormal variation is detected, a trip signal is sent from the detector 53 to the control device 300.

  When the control device 300 detects the input of the trip signal, the stop valve 50 is automatically fully closed by the command signal from the control device 300 to block the flow of the extracted steam into the carbon dioxide separation and recovery device 200. Further, the switching valve 49 is opened by a command signal from the control device 300, the supply destination of the extracted steam is switched from the carbon dioxide separation and recovery device 200 to the first condenser 9, and the excess extracted steam is temporarily recovered. It flows into the first condenser 9 through the air pipe 48 and is collected. Thereafter, the opening of the second switching valve 47 and the second low-pressure turbine inlet control valve 43 is adjusted while the switching valve 49 is gradually closed by the command signal of the control device 300, and the destination of the extracted steam is changed to the second low-pressure turbine 42. Gradually switch control to. Further, when the surplus steam supply destination is switched from the carbon dioxide separation and recovery device 200 to the first condenser 9 and the second low-pressure turbine 42, the control device 300 detects the pressure fluctuation of the medium-pressure turbine exhaust. Based on the signal from the pressure detector 52, the switching valve 49, the switching valve 47, and the second low-pressure turbine inlet control valve 43 are controlled so that the intermediate-pressure turbine exhaust does not excessively decrease pressure by switching the flow path. Control the opening. If medium-pressure turbine exhaust steam is extracted excessively by switching the supply flow path, the pressure of the intermediate-pressure turbine exhaust may drop excessively, and the intermediate-pressure turbine final stage blade may be subjected to a load exceeding the allowable amount. According to this configuration, it is possible to perform flow path switching control while avoiding a load on the final stage blade of the intermediate pressure turbine.

  The surplus steam that has flowed into the second low pressure turbine from the intermediate pressure turbine by switching the flow path drives the second low pressure turbine and drives the generator 44 to obtain electric power. The steam discharged by driving the second low-pressure turbine is collected in the condenser 45, condensed, and sent to the boiler 1.

  The amount of steam required by the reboiler 25 is much larger than the amount of steam required by the reclaimer 26, and about 15% to 20% of the total amount of evaporation of the boiler is required. Although a large amount of surplus steam is generated, the emergency escape function of surplus steam can be effectively exhibited by performing the control operation described above with the control device 300. Therefore, it is possible to avoid the steam that exceeds the allowable amount from abruptly flowing into the low-pressure turbine (first low-pressure turbine) side of the steam turbine apparatus, and the load fluctuations of the boiler 1 and the steam turbine due to surplus steam are suppressed, so carbon dioxide The stable operation of the fossil fuel-fired thermal power generation system 100 can be continued even when the separation and recovery device 200 is in an emergency stop.

  Further, even when the carbon dioxide separation / recovery device 200 is stopped, it is possible to supply the second low-pressure turbine to recover the electric power without throwing away a large amount of surplus steam, thereby increasing the power generation amount.

  A fossil fuel-fired thermal power generation system equipped with a carbon dioxide separation and recovery device according to a second embodiment of the present invention will be described with reference to FIGS.

The fossil fuel-fired thermal power generation system provided with the carbon dioxide separation and recovery device of the second embodiment, which is the present embodiment, is a fossil fuel-fired thermal power generation system provided with the carbon dioxide separation and recovery device of the first embodiment described above. Since the basic configuration is common, description of the configuration common to both will be omitted, and only different parts will be described below.

  The fossil fuel-fired thermal power generation system equipped with the carbon dioxide separation and recovery device according to the second embodiment shown in FIG. 3 separates carbon dioxide from the fossil fuel-fired thermal power generation system 100 constituting the steam turbine device and the boiler exhaust gas. And a carbon dioxide separation and recovery device 200 for recovery.

  In this embodiment, the fossil fuel-fired thermal power generation system 100 includes a second extraction pipe 54 that branches from the high-pressure turbine exhaust pipe 4 of the high-pressure turbine 3 and a part of the steam that flows down the high-pressure turbine exhaust pipe 4 flows down. The back pressure turbine air supply pipe 55 connected to the first extraction pipe 40 through which part of the steam flowing down the intermediate pressure turbine exhaust pipe 7 flows, and the extraction extracted through the second extraction pipe 54 and the back pressure turbine air supply pipe 55 A back pressure turbine 56 driven by steam and a generator 65 that generates electric power by the power of the back pressure turbine 56 are installed.

  On the inlet side of the back pressure turbine 56, there are a first back pressure turbine inlet control valve 59 for controlling the amount of steam flowing from the second extraction pipe 54 side to the back pressure turbine 56, and a back pressure turbine supply pipe 55 side. A second back-pressure turbine inlet control valve 60 that controls the amount of steam flowing into the pressure turbine 56 is provided. Further, on the outlet side of the back pressure turbine 56, a back pressure turbine exhaust pipe 61 for driving the back pressure turbine 56 to flow down the reduced back pressure turbine exhaust and a back pressure turbine exhaust pipe 61 are provided. PCC device air supply piping which is connected to the stop valve 62 and the back pressure turbine exhaust pipe 61 and supplies back pressure turbine exhaust to the reboiler 25 and the reclaimer 26 installed in the carbon dioxide separation and recovery device 200 described later. 41.

  A second low pressure turbine inlet pipe 63 having a stop valve 64 is connected to the second extraction pipe 54. The second low-pressure turbine inlet pipe 63 is connected to the second low-pressure turbine 42, and is configured to guide the steam flowing down the second low-pressure turbine inlet pipe 63 to the second low-pressure turbine 42.

  Further, a second condenser air supply pipe 66 that branches from the second low-pressure turbine inlet pipe 63 and communicates with the first condenser 9 is provided, and a switching valve 67 is provided in the second condenser air supply pipe 66. Is provided.

  The fossil fuel-fired thermal power generation system 100 branches from the first extraction pipe 40 and communicates with the second low-pressure turbine inlet pipe 63, and guides the extraction steam flowing down the first extraction pipe 40 to the second low-pressure turbine 42. A third bleed pipe 70 is provided. The third extraction pipe 70 is provided with a switching valve 71 that switches and controls the flow path of the extraction steam to the second low-pressure turbine side.

  Further, the first extraction pipe 40 branches downstream from the condenser air supply pipe 48 and the third extraction pipe 70, and is connected to the PCC device air supply pipe 41 so that the extraction steam flowing down the first extraction pipe 40 is back-flowed. A first back pressure turbine bypass pipe 72 that bypasses the pressure turbine 56 and leads to the PCC device air supply pipe 41 is provided. The back pressure turbine bypass pipe 72 includes a switching valve 73.

  The high-pressure turbine exhaust pipe 4 is branched downstream of the second extraction pipe 54 and connected to the first back-pressure turbine bypass pipe 72, and the extraction steam of the high-pressure turbine bypasses the back-pressure turbine 56 and is sent to the PCC device. A second back pressure turbine bypass pipe 74 is provided that passes through the air pipe 41 and leads to the reboiler 25 and the reclaimer 26 of the carbon dioxide separation and recovery device 200. The second back pressure turbine bypass pipe 74 includes a switching valve 68 that controls the amount of extracted steam that bypasses the back pressure turbine.

  FIG. 4 is a partial view showing a part of the fossil fuel-fired thermal power generation system 100 in the fossil fuel-fired thermal power generation system equipped with the carbon dioxide separation and recovery device of the second embodiment shown in FIG.

  The fossil fuel-fired thermal power generation system 100 is provided with a control device 400, and the operation of the second low-pressure turbine 42 and the back pressure turbine 56 is controlled by the control device 400.

  In the fossil fuel-fired thermal power generation system 100 according to the second embodiment, the steam is extracted from the intermediate pressure turbine exhaust pipe 7 during the steam turbine rated load operation, and the first extraction pipe 40, the back pressure turbine air supply pipe 55, and the second A system in which medium-pressure turbine exhaust is supplied to the back-pressure turbine 56 through the back-pressure turbine inlet control valve 60 is adopted. On the other hand, when the steam turbine shifts from the rated load operation to the partial load operation, the steam pressure of the exhaust of the intermediate pressure turbine 6 decreases and cannot be sufficiently pumped to the back pressure turbine. The high pressure turbine 3 to the high pressure turbine exhaust pipe instead of the system for supplying the intermediate pressure turbine exhaust to the back pressure turbine 56 through the first extraction pipe 40, the back pressure turbine air supply pipe 55, and the back pressure turbine air supply pipe side control valve 60. 4 is switched to a system in which a part of the high-pressure steam flowing down to 4 is supplied to the back-pressure turbine 56 through the second extraction pipe 54 and the first back-pressure turbine inlet control valve 59, and the steam necessary for driving the back-pressure turbine 56. The pressure is secured.

  In the fossil fuel-fired thermal power generation system 100, when the steam turbine is in partial load operation, a command signal is transmitted from the control device 400 to open the switching valve 57 provided in the second extraction pipe, and the high-pressure turbine 3 The extracted steam is guided to the back pressure turbine 56, the opening degree of the first back pressure turbine inlet control valve 59 is adjusted to control the flow rate, and the back pressure turbine 56 is driven and controlled by the extracted steam from the high pressure turbine.

  Next, after the steam turbine shifts from the partial load operation to the rated load operation, the steam pressure flowing through the intermediate pressure turbine exhaust pipe 7 rises to a pressure sufficient to pump to the back pressure turbine 56, and then the control device 400. The control valve 54 and the first back pressure turbine inlet control valve 59 are closed and the switch valve 58 is opened to guide the bleed steam of the intermediate pressure turbine to the back pressure turbine 56, and the second back pressure turbine inlet. The flow rate is controlled by adjusting the opening degree of the control valve 60, and the back pressure turbine 56 is driven and controlled by the steam extracted from the intermediate pressure turbine exhaust. The back pressure turbine exhaust after driving the back pressure turbine 56 is sent to the reboiler 25 and the reclaimer 26 of the carbon dioxide separation and recovery device 200 through the back pressure turbine exhaust pipe 61 and the PCC device air supply pipe 41.

  By the way, when the back pressure turbine 56 trips for some reason during partial load operation of the steam turbine, for example, when an abnormal value of the generator output signal of the back pressure turbine 56 is input to the control device 400, the control device 400. A command signal is transmitted from the control valve 54 to close the switching valve 54 and the first back pressure turbine inlet control valve 59. Further, the switching valve 68 is opened, and the extracted steam is guided to the PCC device air supply pipe 41 through the second back pressure turbine bypass pipe 74 and the first back pressure turbine bypass pipe 72.

  Further, when the carbon dioxide separation and recovery device 200 trips during partial load operation of the steam turbine, for example, the rich absorbent transfer pump 23 or the lean absorbent transfer pump 32 that is the main equipment of the carbon dioxide separation and recovery device 200 trips. When the operation of the carbon dioxide separation and recovery device 200 is urgently stopped and the steam supplied to the reboiler 25 from the steam turbine cycle of the fossil fuel-fired thermal power generation system 100 needs to be immediately stopped, the rich absorbent transfer pump 23 In addition, a rich absorption liquid transfer pump trip signal 23 a or a lean absorption liquid transfer pump trip signal 32 a input from sensors installed in the lean absorption liquid transfer pump 32 is sent to the control device 400.

  As another means for detecting an abnormality in the carbon dioxide separation / recovery apparatus 200, the first air supply pressure detector 75 provided in the back pressure turbine air supply pipe 55 causes the steam flowing down in the PCC apparatus air supply pipe 41 to flow. When a change in pressure is detected and the detector 75 detects an abnormal change in pressure, a trip signal is sent from the detector 75 to the control device 400.

  When the back pressure turbine 56 is stopped and the bypass system is used, the back pressure turbine air supply pipe 55 is not used, and the first air supply pressure detector 75 cannot be used. Therefore, the second air supply pressure detector 76 provided on the downstream side of the junction of the PCC device air supply pipe 41 and the first back pressure turbine bypass pipe 72 detects the pressure fluctuation of the air supply, and the detector 76 detects the pressure. When an abnormal fluctuation is detected, a trip signal is sent from the detector 76 to the control device 400.

  When the control device 400 receives the input of the trip signal, the switching valves 57 and 68 are closed and the switching valve 67 is opened by the command signal from the control device 400, and the extracted steam is supplied to the second low-pressure turbine inlet pipe 63 and the second recovery valve. It is guided to the first condenser 9 through the water supply pipe 66 and collected. Thereafter, the opening of the stop valve 64 and the inlet control valve 43 of the second low-pressure turbine 42 is adjusted while the switching valve 67 is gradually closed by the command signal of the control device 400, and the destination of the extracted steam is changed to the second low-pressure turbine 42. Gradually switch control to.

  On the other hand, when the back pressure turbine 56 trips for some reason during the rated load operation of the steam turbine, a command signal is transmitted from the control device 400, the switching valve 58 is closed, the switching valve 73 is opened, and the extracted steam is discharged. 1 It is led to the PCC device air supply pipe 41 through the back pressure turbine bypass pipe 72.

  When the carbon dioxide recovery device trips, a trip signal is input to the control device 400 from the rich absorbing liquid transfer pump 23, the lean absorbing liquid transfer pump 32, the detectors 75 and 76, and the like.

  When the control device 400 receives the trip signal of the carbon dioxide separation and recovery device 200, the switching valves 58 and 73 are closed by the command signal from the control device 400, the switching valve 49 is opened, and the excess steam is temporarily removed from the first condenser 9. Collect with. Thereafter, the switching valve 49 is gradually closed according to the command signal of the control device 400, and the opening degree of the switching valve 71 and the inlet control valve 43 of the second low-pressure turbine 42 is adjusted so that the supply destination of the extracted steam is the second low-pressure turbine. The control is gradually switched to 42. Further, when switching the flow of the extracted steam to the first condenser 9 and the second low-pressure turbine 42 through the third extraction pipe 70 and the condenser supply pipe 48, the control device 400 changes the pressure fluctuation of the intermediate pressure turbine exhaust. Based on the signal of the intermediate pressure turbine exhaust pressure detector 52 to be detected, the switching valve 49, the switching valve 71, and the second low pressure are set so that the intermediate pressure turbine exhaust does not drop excessively beyond a predetermined set value by switching the flow path. The opening degree of the turbine inlet control valve 43 is controlled. If the medium-pressure turbine exhaust steam is extracted excessively due to the switching of the flow path, the pressure of the intermediate-pressure turbine exhaust will drop excessively, and there may be a load exceeding the allowable amount on the final stage blade of the intermediate-pressure turbine. According to the configuration, the flow path switching control can be performed while avoiding a load on the final stage blade of the intermediate pressure turbine.

  In the fossil fuel-fired thermal power generation system equipped with the carbon dioxide separation and recovery device having the above-described configuration, during rated load operation, the exhaust of the intermediate pressure turbine 6 can be supplied to the back pressure turbine 56 to generate electric power, and during partial load operation, The exhaust from the high pressure turbine 3 can be supplied to the back pressure turbine 56 to generate electric power.

  Further, according to the control described above, even when the back pressure turbine 56 trips for some reason during partial load operation and rated load operation, the extracted steam is discharged from the back pressure turbine 56 while stopping the operation of the back pressure turbine 56. Can be supplied to the carbon dioxide separation and recovery device 200 side, and the carbon dioxide separation and recovery device can be continuously operated.

  Further, even when the carbon dioxide separation and recovery device 200 is stopped, surplus steam can escape to the second low-pressure turbine, and steam exceeding the allowable amount suddenly flows into the low-pressure turbine (first low-pressure turbine) side of the steam turbine. This can be avoided, and load fluctuations of the boiler 1 and the steam turbine due to surplus steam are suppressed, so that stable operation of the fossil fuel-fired thermal power generation system 100 can be continued.

  Further, even when the carbon dioxide separation / recovery device 200 and the back pressure turbine are stopped, a large amount of surplus steam can be sent to the second low pressure turbine without being discarded and recovered as electric power, thereby increasing the power generation amount.

1 Boiler 3 High Pressure Turbine 6 Medium Pressure Turbine 7 Medium Pressure Turbine Exhaust Pipe 8 First Low Pressure Turbine 9 Condenser 17 Absorption Tower 22 Regeneration Tower 25 Reboiler 26 Reclaimer 40 First Extraction Pipe 41 PCC Device Air Supply Pipe 42 Second Low Pressure Turbine 44, 65 Generator 46 Second low pressure turbine air supply pipe 47, 49, 57, 58, 67, 68, 71, 73 Switching valve 50, 62, 64 Stop valve 48 Condenser air supply pipe 52 Air supply pressure detector 54 2 Extraction pipe 55 Back pressure turbine supply pipe 56 Back pressure turbine 61 Back pressure turbine exhaust pipe 63 Second low pressure turbine inlet pipe 66 Second condenser supply pipe 70 Third extraction pipe 72 First back pressure turbine bypass valve 74 Two back-pressure turbine bypass valve 100 Fossil fuel-fired thermal power generation system 200 Carbon dioxide separation and recovery device 300, 400 Control device

Claims (5)

A boiler that burns fossil fuel to generate steam, a high-pressure turbine that is driven by steam generated in the boiler, an intermediate-pressure turbine that is driven by steam that is discharged from the high-pressure turbine and reheated by the boiler, and Fossil fuel-fired thermal power comprising a first low-pressure turbine driven by steam discharged from an intermediate-pressure turbine, and a steam turbine device having a condenser for condensing steam discharged from the first low-pressure turbine. A power generation system;
Absorbing carbon dioxide by circulating the absorption liquid between the absorption tower for absorbing and recovering carbon dioxide contained in the boiler exhaust gas discharged by burning fossil fuel from the boiler and the absorption tower Fossil fuel-fired thermal power generation equipped with a carbon dioxide separation and recovery device comprising: an absorption liquid regeneration tower for separating oxygen dioxide from the absorption liquid; and a carbon dioxide separation and recovery device comprising a reboiler for supplying steam to the regeneration tower A system,
An extraction pipe for supplying the extracted steam extracted from the exhaust steam of the intermediate pressure turbine to the reboiler as a heat source;
A first steam pipe communicating with the condenser and the extraction pipe;
A second low-pressure turbine provided separately from the steam turbine device;
A generator for generating power with the power of the second low-pressure turbine;
A second steam pipe that communicates with the extraction pipe and the second low-pressure turbine and guides the extraction steam that flows down the extraction pipe to the second low-pressure turbine;
And a valve for switching and controlling the flow path through which the extraction steam flows, provided in the extraction pipe, the first steam pipe, and the second steam pipe. Fossil fuel-fired thermal power generation system equipped with a recovery device. A fossil fuel-fired thermal power generation system comprising the carbon dioxide separation and recovery device according to claim 1,
A pressure detector for detecting the pressure of steam discharged from the intermediate pressure turbine;
The trip signal from the carbon dioxide separation and recovery device is received, and the opening / closing control of the valves provided in the extraction pipe and the first and second steam pipes is performed using the pressure value input from the pressure detector. A control device for performing,
When the control device receives a trip signal from the carbon dioxide separation and recovery device, the control device closes a valve provided in the extraction pipe so that the pressure value does not exceed a predetermined value.
Open control of the valve provided in the first steam pipe, and then close control of the valve provided in the first steam pipe and open control of the valve provided in the second steam pipe, A fossil fuel-fired thermal power generation system characterized in that start-up control of the second low-pressure turbine is performed. A boiler that burns fossil fuel to generate steam, a high-pressure turbine that is driven by steam generated in the boiler, an intermediate-pressure turbine that is driven by steam that is discharged from the high-pressure turbine and reheated by the boiler, and Fossil fuel-fired thermal power comprising a first low-pressure turbine driven by steam discharged from an intermediate-pressure turbine, and a steam turbine device having a condenser for condensing steam discharged from the first low-pressure turbine. A power generation system;
Absorbing carbon dioxide by circulating the absorption liquid between the absorption tower for absorbing and recovering carbon dioxide contained in the boiler exhaust gas discharged by burning fossil fuel from the boiler and the absorption tower Fossil fuel-fired thermal power generation equipped with a carbon dioxide separation and recovery device comprising: an absorption liquid regeneration tower for separating oxygen dioxide from the absorption liquid; and a carbon dioxide separation and recovery device comprising a reboiler for supplying steam to the regeneration tower A system,
A back pressure turbine,
A generator driven by the power of the back pressure turbine;
A first extraction pipe for supplying steam extracted from the exhaust steam of the intermediate pressure turbine as a working fluid to the back pressure turbine;
A second extraction pipe that supplies steam extracted from the exhaust steam of the high-pressure turbine to the back-pressure turbine as a working fluid;
A first steam pipe for supplying the exhaust steam of the back pressure turbine to the reboiler;
A second low-pressure turbine provided separately from the steam turbine device;
A generator for generating power with the power of the second low-pressure turbine;
A second steam pipe for guiding the extracted steam flowing down the first extraction pipe to the condenser;
A first steam supply system that guides extracted steam flowing down the first extracted piping to the second low-pressure turbine;
A third steam pipe for guiding the extracted steam flowing down the second extracted pipe to the condenser;
A second steam supply system for guiding the extracted steam flowing down the second extracted piping to the second low-pressure turbine;
It said first and second bleed pipe, third and steam pipe to the first free, provided the first and second steam supply system, the valve for the extraction steam to control switching of the flow channel flowing down When,
A fossil fuel-fired thermal power generation system equipped with a carbon dioxide separation and recovery device. A fossil fuel-fired thermal power generation system comprising the carbon dioxide separation and recovery device according to claim 3,
A pressure detector for detecting the pressure of steam discharged from the intermediate pressure turbine;
Receiving a trip signal from the carbon dioxide separation and recovery device, using the pressure value input from the pressure detector, and said first and second bleed pipe, and a third steam pipe to the first free, second A control device that controls opening and closing of valves provided in the first and second steam supply systems,
When the control device receives a trip signal from the carbon dioxide separation and recovery device during partial load operation of the steam turbine device, the control device closes a valve provided in the second extraction pipe, and the pressure value is determined in advance. The valve provided in the third steam pipe is opened and controlled so that the valve provided in the third steam pipe is closed and the second steam supply system is closed. Controlling the opening of the second low-pressure turbine by opening the provided valve;
When a trip signal is received from the carbon dioxide separation and recovery device during rated load operation of the steam turbine device, the valve provided in the first extraction pipe is closed and the pressure value exceeds a predetermined value. So that the valve provided in the second steam pipe is controlled to open, and then the valve provided in the second steam pipe is closed and the valve provided in the first steam supply system is controlled. A fossil fuel-fired thermal power generation system characterized in that the second low-pressure turbine is controlled to open and controlled to start. A fossil fuel-fired thermal power generation system comprising the carbon dioxide separation and recovery device according to claim 3,
A first back pressure turbine bypass system for supplying the extracted steam flowing down the first extraction pipe to the reboiler by bypassing the back pressure turbine;
A second back pressure turbine bypass system for supplying the extracted steam flowing down the second extraction pipe to the reboiler by bypassing the back pressure turbine;
Valves provided in the first and second back pressure turbine bypass systems;
When a trip signal is received from the back pressure turbine, the valves provided in the first and second extraction pipes are closed and controlled, and the valves provided in the first and second back pressure turbine bypass systems are controlled. A fossil fuel-fired thermal power generation system comprising a carbon dioxide separation and recovery device.

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