Waste heat power generation system of vertical heat recovery coke oven

Abstract

The embodiment of the utility model provides a waste heat power generation system of a vertical heat recovery coke oven. The waste heat power generation system comprises the vertical heat recovery coke oven, a waste gas waste heat boiler, a power generator, a steam turbine, a main steam pipeline, a low-temperature reheat steam pipeline, a high-temperature reheat steam pipeline, a condensation deoxidization pipeline, a high-pressure bypass device and a low-pressure bypass device. The reheater is arranged in the waste gas waste heat boiler, steam generated by the waste gas waste heat boiler is heated to at least ultrahigh temperature and ultrahigh pressure, and the steam turbine drives the generator to generate power by using the steam which is at least heated to ultrahigh temperature and ultrahigh pressure, so that high-parameter and high-energy-efficiency waste heat utilization of the vertical heat recovery coke oven waste heat power generation system is realized; and the energy utilization rate is improved. A high-pressure bypass device and a low-pressure bypass device are additionally arranged, and the high-pressure bypass device is connected with the main steam pipeline and the low-temperature reheat steam pipeline in an on-off mode; the low-pressure bypass device is connected with the high-temperature reheat steam pipeline and the condensation deoxidization pipeline in an on-off mode. When the steam turbine has an accident, the condensed water can be recycled.

Description

Vertical Waste Heat Recovery Coke Oven Power Generation System Technical Field

[0001] The utility model relates to the technical field of coking power generation, in particular to a vertical waste heat recovery coke oven power generation system. Background Technique

[0002] The dry quenching process is an advanced coke production technology. Its working principle is to use cold inert gas (nitrogen or waste gas) to exchange heat with red-hot coke in the dry quenching furnace to cool the red coke. The inert gas that absorbs the heat of the red coke transfers the heat to the waste heat boiler to generate steam, and the generated steam can be supplied to the steam turbine generator set for power generation.

[0003] The high-efficiency energy-saving heat exchange vertical waste heat recovery coke oven has the characteristics of remarkable clean environmental protection, no chemical production pollution, high production efficiency, low investment, small floor area, low coal blending cost, etc., and is widely used. In some cases, the waste heat boiler配套 with the vertical waste heat recovery coke oven is a high-temperature and high-pressure boiler, and the corresponding steam turbine generator is a high-temperature and high-pressure generator set. The feed water temperature of the high-temperature and high-pressure boiler is approximately 104 °C, the steam temperature provided by the high-temperature and high-pressure boiler for the high-temperature and high-pressure generator is approximately 540 °C, and the steam pressure is approximately 9.8 MPa. The power generation efficiency of this kind of high-temperature and high-pressure thermal system has limitations, which limits the energy utilization rate, and the economic benefits of waste heat power generation need to be improved. Summary of the Invention

[0004] The purpose of the embodiment of the utility model is to provide a vertical waste heat recovery coke oven power generation system to improve the recovery efficiency of flue gas heat and further improve the economic benefits of waste heat power generation. The specific technical solution is as follows:

[0005] This application provides a vertical waste heat recovery coke oven power generation system, including:

[0006] A vertical waste heat recovery coke oven;

[0007] An exhaust gas waste heat boiler, including an economizer, an evaporator, a superheater, and a reheater that respectively exchange heat with the high-temperature flue gas provided by the vertical waste heat recovery coke oven. The economizer, evaporator, and superheater are used to sequentially heat the feed water entering the exhaust gas waste heat boiler into steam, and the steam is heated to at least ultra-high temperature and ultra-high pressure;

[0008] A generator;

[0009] A steam turbine, drivingly connected to the generator, for using steam to drive the generator to generate electricity. The steam turbine includes a high-pressure cylinder and a low-pressure cylinder;

[0010] A main steam pipeline, connecting the steam outlet of the superheater and the steam inlet of the high-pressure cylinder;

[0011] A low-temperature reheated steam pipeline, connecting the steam outlet of the high-pressure cylinder and the steam inlet of the reheater;

[0012] The high-temperature reheat steam pipeline connects the steam outlet of the reheater to the steam inlet of the low-pressure cylinder.

[0013] The condensate deaerator pipeline connects the economizer's water inlet and the low-pressure cylinder's exhaust port.

[0014] High-pressure bypass device, which can connect the main steam pipeline and the low-temperature reheat steam pipeline;

[0015] The low-pressure bypass device can connect and disconnect the high-temperature reheat steam pipeline and the condensate deaerator pipeline.

[0016] In some embodiments, the low-pressure bypass device includes a first bypass, a first valve, and a multi-stage desuperheating and pressure reducing device; the first bypass connects a high-temperature reheat steam pipeline and a condensate deaeration pipeline, and the first valve and the multi-stage desuperheating and pressure reducing device are disposed in the first bypass.

[0017] In some embodiments, the condensate deaerator pipeline includes an exhaust pipe, a condensing unit, a condensate pipe, a heater, a deaerator, and a feedwater pipe; the exhaust pipe is connected to the exhaust port of the low-pressure cylinder and the inlet of the condensing unit, respectively; the condensate pipe is connected to the outlet of the condensing unit and the inlet of the deaerator, respectively; the feedwater pipe is connected to the outlet of the deaerator and the inlet of the economizer; along the water flow direction of the condensate pipe, the heater and the deaerator are sequentially arranged on the condensate pipe; the first bypass is connected to the high-temperature reheat steam pipeline and the exhaust pipe; the low-pressure cylinder provides non-adjustable extraction steam to the heater and the deaerator respectively.

[0018] In some embodiments, the heater includes a first low-pressure heater and a second low-pressure heater; along the water flow direction of the condensate pipe, the second low-pressure heater and the first low-pressure heater are sequentially arranged on the condensate pipe and located between the deaerator and the condenser.

[0019] In some embodiments, the condensate deaeration pipeline includes a shaft seal heater, and along the water flow direction of the condensate pipe, the shaft seal heater, the second low-pressure heater, and the first low-pressure heater are sequentially arranged in the condensate pipe and located between the deaerator and the condensation device; the condensate deaeration pipeline includes a condensate pump, which is arranged in the condensate pipe and located between the shaft seal heater and the condensation device.

[0020] In some embodiments, the condensate deaeration pipeline includes a boiler feedwater pump, which is installed in the feedwater pipe.

[0021] In some embodiments, the high-pressure bypass device includes a second bypass and a second valve; the second bypass connects the main steam pipeline and the cryogenic reheat steam pipeline, and the second valve is disposed in the second bypass.

[0022] In some embodiments, the superheater includes a low-temperature superheater and a high-temperature superheater; the reheater includes a low-temperature reheater and a high-temperature reheater; along the flow direction of the high-temperature flue gas in the waste gas waste heat boiler, the high-temperature superheater, high-temperature reheater, low-temperature superheater, low-temperature reheater, evaporator, and economizer are arranged in sequence, and the economizer, evaporator, low-temperature superheater, and high-temperature superheater are used to heat the feedwater entering the waste gas waste heat boiler in sequence, and the low-temperature reheater and high-temperature reheater are used to heat the steam from the low-temperature reheat steam pipeline in sequence.

[0023] In some embodiments, the steam pressure output by the high-temperature superheater is P1, the temperature is T1, 13.7MPa≤P1<16.7MPa, and 560℃<T1≤610℃.

[0024] In some embodiments, the steam pressure output by the high-temperature superheater is P2, the temperature is T2, 16.7MPa≤P2<22.1MPa, and 560℃<T2≤610℃.

[0025] The vertical heat recovery coke oven waste heat power generation system provided in this embodiment includes: a vertical heat recovery coke oven, a waste gas heat boiler, a generator, a steam turbine, a main steam pipeline, a low-temperature reheat steam pipeline, a high-temperature reheat steam pipeline, a condensation deaerator pipeline, a high-pressure bypass device, and a low-pressure bypass device. The waste gas heat recovery boiler includes an economizer, an evaporator, a superheater, and a reheater, which exchange heat with the high-temperature flue gas provided by the vertical heat recovery coke oven. The economizer, evaporator, and superheater are used to sequentially heat the feedwater entering the waste gas heat recovery boiler into steam, and the steam is heated to at least ultra-high temperature and ultra-high pressure. A steam turbine and a generator are connected for driving the generator to generate electricity using steam. The steam turbine includes a high-pressure cylinder and a low-pressure cylinder. The main steam pipeline connects the steam outlet of the superheater and the steam inlet of the high-pressure cylinder. The low-temperature reheat steam pipeline connects the steam outlet of the high-pressure cylinder and the steam inlet of the reheater. The high-temperature reheat steam pipeline connects the steam outlet of the reheater and the steam inlet of the low-pressure cylinder. The condensate deaerator pipeline connects the water inlet of the economizer and the steam outlet of the low-pressure cylinder. A high-pressure bypass device connects the main steam pipeline and the low-temperature reheat steam pipeline in a switchable manner. A low-pressure bypass device connects the high-temperature reheat steam pipeline and the condensate deaerator pipeline in a switchable manner.

[0026] When the steam turbine is operating normally, both the high-pressure bypass and low-pressure bypass devices are disconnected. The high-pressure bypass disconnects the main steam pipeline from the cryogenic reheat steam pipeline, while the low-pressure bypass disconnects the high-temperature reheat steam pipeline from the condensation and deaeration pipeline. The main steam pipeline delivers steam to the high-pressure cylinder to drive the turbine, which in turn powers the generator. The cryogenic steam discharged from the high-pressure cylinder returns to the reheater via the cryogenic reheat steam pipeline for secondary heating, and then enters the low-pressure cylinder via the high-temperature reheat steam pipeline to continue performing work. The condensation and deaeration pipeline condenses and deaerates the exhaust steam from the low-pressure cylinder before supplying it back to the economizer, forming a closed-loop cycle.

[0027] When a turbine accident occurs, the main steam valve closes, and both the high-pressure and low-pressure bypass devices are opened. The high-pressure bypass device connects to the main steam pipeline and the low-temperature reheat steam pipeline, while the low-pressure bypass device connects to the high-temperature reheat steam pipeline and the condensate deaerator pipeline. Steam is delivered from the main steam pipeline to the high-pressure bypass device, then enters the reheater and the low-pressure bypass device, and finally flows into the condensate deaerator pipeline to be cooled into condensate for recovery.

[0028] In the embodiments of this application, on the one hand, the structure of the waste gas waste heat boiler is improved by installing a reheater inside the waste gas waste heat boiler and raising the steam generated by the waste gas waste heat boiler to at least ultra-high temperature and ultra-high pressure. The turbine uses the steam heated to at least ultra-high temperature and ultra-high pressure to drive the generator to generate electricity, realizing high-parameter and high-efficiency waste heat utilization of the coke oven waste heat power generation system, further improving the energy utilization rate of high-temperature flue gas and increasing power generation efficiency. On the other hand, the turbine-side structure is improved by adding a high-pressure bypass device and a low-pressure bypass device. The high-pressure bypass device can connect the main steam pipeline and the low-temperature reheat steam pipeline; the low-pressure bypass device can connect the high-temperature reheat steam pipeline and the condensation deaerator pipeline. When the steam turbine is operating normally, both the high-pressure bypass device and the low-pressure bypass device are in the open state. When a steam turbine accident occurs, the main steam valve of the steam turbine is closed, and both the high-pressure bypass device and the low-pressure bypass device are adjusted to the open state. The main steam pipeline delivers steam to the high-pressure bypass device, and then into the reheater and the low-pressure bypass device. After that, it enters the condensate deaerator pipeline, where it can be cooled into condensate and recycled.

[0029] Of course, any product implementing this utility model does not necessarily need to achieve all of the above advantages at the same time. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.

[0031] Figure 1 is a schematic diagram of the structural layout of a vertical heat recovery coke oven waste heat power generation system provided in an embodiment of this application.

[0032] The attached figures are labeled as follows:

[0033] Waste heat boiler 10, economizer 11, evaporator 12, superheater 13, low-temperature superheater 131, high-temperature superheater 132, reheater 14, low-temperature reheater 141, high-temperature reheater 142, steam drum 15, generator 20, steam turbine 30, high-pressure cylinder 31, low-pressure cylinder 32, main steam pipeline 40, low-temperature reheat steam pipeline 50, high-temperature reheat steam pipeline 60, condensate deaerator pipeline 70, exhaust pipe 71. Condensation device 72, condensate pipe 73, heater 74, first low-pressure heater 741, second low-pressure heater 742, shaft seal heater 79, deaerator 75, demineralized water inlet pipe 751, condensate pump 76, boiler feed pump 77, feed pipe 78, high-pressure bypass device 80, second bypass 81, second valve 82, low-pressure bypass device 90, first bypass 91, first valve 92, multi-stage desuperheater and pressure reducer 93. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art based on this application are within the protection scope of the present utility model.

[0035] The purpose of this application is to improve waste heat recovery efficiency, achieve efficient energy utilization, reduce energy consumption and production costs, and reduce environmental pollution. This solution addresses the problem of low heat recovery efficiency of flue gas at the tail end of vertical waste gas boiler processes by employing a high-pressure, high-parameter waste heat utilization system, thereby improving the energy conversion efficiency of the coking process and the economic benefits for enterprises.

[0036] Figure 1 is a schematic diagram of the structural layout of a vertical heat recovery coke oven waste heat power generation system provided in an embodiment of this application. As shown in Figure 1, a vertical heat recovery coke oven waste heat power generation system includes: a vertical heat recovery coke oven (not shown), a waste gas waste heat boiler 10, a generator 20, a steam turbine 30, a main steam pipeline 40, a low-temperature reheat steam pipeline 50, a high-temperature reheat steam pipeline 60, a condensation deaerator pipeline 70, a high-pressure bypass device 80, and a low-pressure bypass device 90.

[0037] The waste gas waste heat boiler 10 includes an economizer 11, an evaporator 12, a superheater 13, and a reheater 14, which exchange heat with the high-temperature flue gas provided by the vertical heat recovery coke oven. The economizer 11, evaporator 12, and superheater 13 are used to sequentially heat the feedwater entering the waste gas waste heat boiler 10 into steam, and the steam is heated to at least ultra-high temperature and ultra-high pressure. A steam turbine 30 and a generator 20 are driven together to generate electricity by using steam to drive the generator 20. The steam turbine 30 includes a high-pressure cylinder 31 and a low-pressure cylinder 32. The main steam pipeline 40 is connected to the superheater 13. The steam outlet of the high-pressure cylinder 31 and the steam inlet of the low-pressure cylinder 32 are connected; the low-temperature reheat steam pipeline 50 connects the steam outlet of the high-pressure cylinder 31 and the steam inlet of the reheater 14; the high-temperature reheat steam pipeline 60 connects the steam outlet of the reheater 14 and the steam inlet of the low-pressure cylinder 32; the condensation deaerator pipeline 70 connects the water inlet of the economizer 11 and the steam outlet of the low-pressure cylinder 32; the high-pressure bypass device 80 can be switched on and off to connect the main steam pipeline 40 and the low-temperature reheat steam pipeline 50; the low-pressure bypass device 90 can be switched on and off to connect the high-temperature reheat steam pipeline 60 and the condensation deaerator pipeline 70.

[0038] The waste gas waste heat boiler 10 also includes a steam drum 15 and a water-cooled wall. The water-cooled wall is arranged around the flue of the high-temperature flue gas of the waste gas waste heat boiler 10. The steam drum 15 is connected to the water-cooled wall, the economizer 11, the evaporator 12 and the superheater 13 respectively.

[0039] The working process of a vertical heat recovery coke oven waste heat power generation system is as follows:

[0040] High-temperature flue gas enters the inlet of the waste gas waste heat boiler 10 through the flue and flows from top to bottom, passing sequentially through the heat exchanger 13, evaporator 12, and economizer 11. The feedwater from the condensate deaerator pipeline 70 enters the waste gas waste heat boiler 10 first, then flows into the economizer 11. The water exchanges heat with the high-temperature flue gas in the economizer 11, raising its temperature to slightly below the saturation temperature under the pressure of the steam drum 15, before leaving the economizer 11 and entering the steam drum 15.

[0041] Water heated by the economizer 11 enters the steam drum 15, mixes with the saturated water inside the steam drum 15, and then enters the evaporator 12 and the water-cooled wall through the downcomer below the steam drum 15.

[0042] The water in the water-cooled wall exchanges heat with the high-temperature flue gas to generate saturated steam, which is then sent to the steam drum 15.

[0043] Water and high-temperature flue gas exchange heat in the evaporator 12 and begin to generate steam. A steam-water mixture is formed inside the tube of the evaporator 12. The steam-water mixture leaves the evaporator 12 and enters the upper part of the steam drum 15.

[0044] The steam drum 15 is equipped with a steam-water separator, which can separate the steam and water in the steam-water mixture. The water falls into the water space inside the steam drum 15, while the steam comes out from the top of the steam drum 15 to the superheater 13.

[0045] Inside the superheater 13, steam and high-temperature flue gas exchange heat and absorb heat, turning saturated steam into superheated steam, which is heated to at least ultra-high temperature and ultra-high pressure.

[0046] When the steam turbine 30 is operating normally, both the high-pressure bypass device 80 and the low-pressure bypass device 90 are disconnected. The high-pressure bypass device 80 disconnects the main steam pipeline 40 from the low-temperature reheat steam pipeline 50, and the low-pressure bypass device 90 disconnects the high-temperature reheat steam pipeline 60 from the condensation deaerator pipeline 70. The main steam pipeline 40 delivers steam to the high-pressure cylinder 31 to drive the steam turbine 30 to rotate, which in turn drives the generator 20 to generate electricity. The low-temperature steam discharged from the high-pressure cylinder 31 returns to the reheater 14 for secondary heating via the low-temperature reheat steam pipeline 50, and then enters the low-pressure cylinder 32 through the high-temperature reheat steam pipeline 60 to continue performing work. The condensation deaerator pipeline 70 condenses and deaerates the exhaust steam from the low-pressure cylinder 32 and then supplies it back to the economizer 11, forming a closed loop.

[0047] When an accident occurs in turbine 30, the main steam valve of turbine 30 is closed, and both the high-pressure bypass device 80 and the low-pressure bypass device 90 are adjusted to the open state. The high-pressure bypass device 80 connects the main steam pipeline 40 and the low-temperature reheat steam pipeline 50, and the low-pressure bypass device 90 connects the high-temperature reheat steam pipeline 60 and the condensate deaerator pipeline 70. The main steam pipeline 40 delivers steam to the high-pressure bypass device 80, then into the reheater 14 and the low-pressure bypass device 90, and finally into the condensate deaerator pipeline 70 for cooling into condensate for recovery.

[0048] In one embodiment of this application, the structure of the waste heat boiler 10 is improved by installing a reheater 14 within the waste heat boiler 10, and raising the steam generated by the waste heat boiler 10 to at least ultra-high temperature and ultra-high pressure. The turbine 30 uses the steam heated to at least ultra-high temperature and ultra-high pressure to drive the generator 20 to generate electricity, realizing high-parameter and high-efficiency waste heat utilization of the coke oven waste heat power generation system, further improving the energy utilization rate of high-temperature flue gas and increasing power generation efficiency. On the other hand, the structure of the turbine 30 is improved by adding a high-pressure bypass device 80 and a low-pressure bypass device 90. The high-pressure bypass device 80 can be switched on and off to connect the main steam pipeline 40 and the low-temperature reheat steam pipeline 50; the low-pressure bypass device 90 can be switched on and off to connect the high-temperature reheat steam pipeline 60 and the condensation deaerator pipeline 70. When the steam turbine 30 is operating normally, both the high-pressure bypass device 80 and the low-pressure bypass device 90 are in the off state. When an accident occurs in the steam turbine 30, the main steam valve of the steam turbine 30 is closed, and both the high-pressure bypass device 80 and the low-pressure bypass device 90 are adjusted to the open state. The main steam pipeline 40 delivers steam to the high-pressure bypass device 80, and then into the reheater 14 and the low-pressure bypass device 90. After that, it enters the condensate deaerator pipeline 70, where it can be cooled into condensate and recycled.

[0049] The low-pressure bypass device 90 includes a first bypass 91, a first valve 92, and a multi-stage desuperheating and pressure reducing device 93; the first bypass 91 is connected to the high-temperature reheat steam pipeline 60 and the condensate deaeration pipeline 70, and the first valve 92 and the multi-stage desuperheating and pressure reducing device 93 are located in the first bypass 91.

[0050] The first bypass 91 is an auxiliary channel connecting the high-temperature reheat steam pipeline 60 and the condensation deaerator pipeline 70. It is used to introduce high-temperature reheat steam into the condensation deaerator pipeline 70 in the event of an accident in the turbine 30. The first bypass 91 can be implemented using a high-temperature alloy pipeline to avoid the risk of steam leakage.

[0051] The first valve 92 can be an electric or pneumatic regulating valve. The multi-stage desuperheating and pressure reducing device 93 includes pressure reducing valves and water spray cooling structures connected in series, which reduce steam pressure and temperature in stages. For example, the multi-stage desuperheating and pressure reducing device 93 can be equipped with a three-stage desuperheating and pressure reducing unit, so that the temperature and pressure parameters of the steam are gradually reduced to the range that the condensation deaeration pipeline 70 can withstand.

[0052] The condensate deaerator pipeline 70 includes an exhaust pipe 71, a condensing device 72, a condensate pipe 73, a heater 74, a deaerator 75, and a feedwater pipe 78. The exhaust pipe 71 is connected to the exhaust port of the low-pressure cylinder 32 and the inlet of the condensing device 72. The condensate pipe 73 is connected to the outlet of the condensing device 72 and the inlet of the deaerator 75. The feedwater pipe 78 is connected to the outlet of the deaerator 75 and the inlet of the economizer 11. Along the water flow direction of the condensate pipe 73, the heater 74 and the deaerator 75 are sequentially arranged on the condensate pipe 73. The first bypass 91 connects the high-temperature reheat steam pipeline 60 and the exhaust pipe 71. The low-pressure cylinder 32 provides non-adjustable extraction steam to the heater 74 and the deaerator 75 respectively.

[0053] The exhaust pipe 71 is a pipe used to transport the steam discharged from the low-pressure cylinder 32. Specifically, it can be made of seamless steel pipe welded together. Its function is to transport the waste heat steam discharged from the turbine 30 to the condensing device 72 for condensation.

[0054] The condensing device 72 is used to convert steam into liquid water, and can be a condenser or an air-cooled island or other equipment.

[0055] Heater 74 uses unadjusted extraction steam provided by low-pressure cylinder 32 to preheat condensate.

[0056] The function of the deaerator 75 is to reduce the oxygen content in the boiler feedwater to prevent pipeline corrosion. It can be a medium-pressure deaerator. The deaerator 75 is equipped with a demineralized water inlet pipe 751 for replenishing demineralized water.

[0057] Non-adjustable extraction steam refers to steam directly extracted from the 30th stage of the steam turbine without active adjustment. This can be achieved by setting up extraction ports, which provide a heat source for heater 74 and deaerator 75.

[0058] Specifically, the heater 74 includes a first low-pressure heater 741 and a second low-pressure heater 742; along the water flow direction of the condensate pipe 73, the second low-pressure heater 742 and the first low-pressure heater 741 are sequentially arranged in the condensate pipe 73 and located between the deaerator 75 and the condensation device 72.

[0059] Specifically, the vertical heat recovery coke oven waste heat power generation system also includes a shaft seal heater 79. Along the water flow direction of the condensate pipe 73, the shaft seal heater 79, the second low-pressure heater 742 and the first low-pressure heater 741 are sequentially arranged in the condensate pipe 73 and located between the deaerator 75 and the condensation device 72.

[0060] Specifically, the condensate deaeration pipeline 70 includes a condensate pump 76, which is installed in the condensate pipe 73 and located between the shaft seal heater 79 and the condensation device 72.

[0061] Specifically, the condensate deaeration pipeline 70 includes a boiler feedwater pump 77, which is installed in the feedwater pipe 78.

[0062] At startup, the plant provides qualified demineralized water to the deaerator 75. After deoxygenation in the deaerator 75, the water is pressurized by the boiler feedwater pump 77 and sent to the waste heat boiler 10. In the waste heat boiler 10, the water undergoes sufficient heat exchange with the high-temperature flue gas, heating it to at least ultra-high temperature and ultra-high pressure steam (ultra-high temperature and ultra-high pressure or subcritical). This steam is then sent to the main steam valve of the high-pressure cylinder 31 of the turbine 30. Low-temperature reheat steam is drawn from the exhaust port of the high-pressure cylinder 31 of the turbine 30 and connected to the reheater 14 of the waste heat boiler 10. After further heat absorption in the reheater 14, the low-temperature reheat steam becomes ultra-high temperature reheat steam, which is then drawn from the outlet header of the reheater 14 and connected to the low-pressure cylinder 32 of the turbine 30.

[0063] After the high-temperature reheat steam has completed its work in the low-pressure cylinder 32 of the turbine 30, it is cooled into condensate by the condenser 72. The condensate is pressurized by the condensate pump 76 and then sent back to the deaerator 75 after passing through the shaft seal heater 79, the second low-pressure heater 742, and the first low-pressure heater 741. It is then circulated to the waste heat boiler 10 by the boiler feedwater pump 77. The turbine 30 has three stages of non-adjustable steam extraction, which are used by the deaerator 75, the second low-pressure heater 742, and the first low-pressure heater 741, respectively.

[0064] This scheme utilizes the synergistic effect of shaft seal heater 79 and multi-stage low-pressure heater to recover heat from turbine exhaust steam, shaft seal steam and multi-stage extraction steam in stages, significantly improving the utilization efficiency of low-temperature heat sources.

[0065] The high-pressure bypass device 80 includes a second bypass 81 and a second valve 82; the second bypass 81 connects the main steam pipeline 40 and the low-temperature reheat steam pipeline 50, and the second valve 82 is located in the second bypass 81.

[0066] The second bypass 81 is a steam delivery channel independent of the high-pressure cylinder 31 of the turbine 30, used to establish a bypass path between the main steam pipeline 40 and the low-temperature reheat steam pipeline 50. The second valve 82 can be an electrically or pneumatically operated regulating valve. When the turbine 30 is operating normally, the second valve 82 is closed. When the turbine 30 experiences a fault, the second valve 82 is opened.

[0067] Specifically, when a fault occurs in the turbine 30, the second valve 82 is opened, and the ultra-high temperature and ultra-high pressure steam in the main steam pipeline 40 directly enters the low-temperature reheat steam pipeline 50 through the second bypass 81, and then enters the reheater 14 for secondary heating. Thus, the steam can maintain reheat circulation without having to pass through the high-pressure cylinder 31 to perform work, avoiding system heat interruption due to the shutdown of the high-pressure cylinder 31. Furthermore, this solution, by setting up the high-pressure bypass device 80, can maintain steam circulation and prevent the reheater 14 from dry-burning when the turbine 30 fails.

[0068] The superheater 13 includes a low-temperature superheater 131 and a high-temperature superheater 132; the reheater 14 includes a low-temperature reheater 141 and a high-temperature reheater 142; along the flow direction of the high-temperature flue gas in the waste gas waste heat boiler 10, the high-temperature superheater 132, the high-temperature reheater 142, the low-temperature superheater 131, the low-temperature reheater 141, the evaporator 12, and the economizer 11 are arranged in sequence, and the economizer 11, the evaporator 12, the low-temperature superheater 131, and the high-temperature superheater 132 are used to heat the feedwater entering the waste gas waste heat boiler 10 in sequence, and the low-temperature reheater 141 and the high-temperature reheater 142 are used to heat the steam from the low-temperature reheat steam pipeline 50 in sequence.

[0069] This scheme sets up two-stage superheaters (low temperature and high temperature) and two-stage reheaters (low temperature and high temperature), arranged sequentially according to the direction of flue gas temperature decay, so that high-grade thermal energy is preferentially used for high-temperature superheating and reheating processes.

[0070] In some embodiments, the steam pressure output by the high-temperature superheater 132 is P1, the temperature is T1, 13.7MPa≤P1<16.7MPa, and 560℃<T1≤610℃; the steam parameters of the turbine 30 are matched with the steam parameters output by the waste heat boiler 10. This solution improves the energy utilization rate of high-temperature flue gas by increasing the steam parameters of the high-temperature superheater 132 and the high-pressure cylinder 31.

[0071] For example, the feedwater temperature of the waste gas waste heat boiler 10 is 133℃, and the steam parameters of the output steam of the waste gas waste heat boiler 10 are P1 = 13.8MPa and T1 = 571℃. The inlet steam parameters of the steam turbine 30 are approximately 13.2MPa and 566℃.

[0072] In some embodiments, the steam pressure output by the high-temperature superheater 132 is P2, the temperature is T2, 16.7MPa≤P2<22.1MPa, and 560℃<T2≤610℃; the steam parameters of the turbine 30 are matched with the steam parameters output by the waste heat boiler 10. This solution further improves the energy utilization rate of high-temperature flue gas by further increasing the steam parameters of the high-temperature superheater 132 and the high-pressure cylinder 31.

[0073] For example, the feedwater temperature of the waste gas waste heat boiler 10 is 133℃, and the steam parameters of the output steam of the waste gas waste heat boiler 10 are P2 = 17.6MPa and T2 = 571℃. The inlet steam parameters of the steam turbine 30 are approximately 16.7MPa and 566℃.

[0074] The embodiments of this application have at least the following advantages:

[0075] 1. In terms of technology, the coking process system requires minimal changes and is easy to implement.

[0076] 2. In terms of investment, taking a vertical waste gas waste heat boiler unit with an annual output of 450,000 tons as an example, the ultra-high temperature and ultra-high pressure scheme only requires about 20 million yuan more in investment than the high temperature and high pressure scheme, which is a small amount of additional investment.

[0077] 3. In terms of economic benefits, taking the 450,000-ton-per-year vertical waste gas waste heat boiler unit and the steam turbine generator set using a pure condensing unit (direct air-cooled type) as an example, the ultra-high temperature and ultra-high pressure scheme increases the annual revenue by about 21 million yuan (calculated at an electricity price of 0.5 yuan), and the investment payback period is about 0.9 years, which is more economically beneficial.

[0078] As the scale of vertical waste gas heat boilers gradually increases, when the capacity of steam turbine generator sets reaches 70MW or above, the energy utilization rate can be further improved by adopting subcritical ultra-high temperature steam turbine generator sets.

[0079] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model are included within the scope of protection of this utility model.

Claims

1. A vertical heat recovery coke oven waste heat power generation system, characterized in that, include: Vertical heat recovery coke oven; The waste heat boiler (10) includes an economizer (11), an evaporator (12), a superheater (13), and a reheater (14) that exchange heat with the high-temperature flue gas provided by the vertical heat recovery coke oven. The economizer (11), the evaporator (12), and the superheater (13) are used to heat the feedwater entering the waste heat boiler (10) into steam in sequence, and the steam is heated to at least ultra-high temperature and ultra-high pressure. A generator (20) and a steam turbine (30) are connected to the generator (20) for generating electricity by using the steam. The steam turbine (30) includes a high-pressure cylinder (31) and a low-pressure cylinder (32). A main steam pipeline (40) is connected to the steam outlet of the superheater (13) and the steam inlet of the high-pressure cylinder (31). Low-temperature reheat steam pipeline (50) connects the steam outlet of the high-pressure cylinder (31) and the steam inlet of the reheater (14); A high-temperature reheat steam pipeline (60) connects the steam outlet of the reheater (14) and the steam inlet of the low-pressure cylinder (32); a condensation deaerator pipeline (70) connects the water inlet of the economizer (11) and the steam outlet of the low-pressure cylinder (32); A high-pressure bypass device (80) can connect the main steam pipeline (40) and the low-temperature reheat steam pipeline (50) in a switchable manner; The low-pressure bypass device (90) can connect the high-temperature reheat steam pipeline (60) and the condensation deaerator pipeline (70) in a switchable manner.

2. The vertical heat recovery coke oven waste heat power generation system according to claim 1, characterized in that, The low-pressure bypass device (90) includes a first bypass (91), a first valve (92), and a multi-stage desuperheating and pressure reducing device (93); the first bypass (91) connects the high-temperature reheat steam pipeline (60) and the condensation deaeration pipeline (70), and the first valve (92) and the multi-stage desuperheating and pressure reducing device (93) are located in the first bypass (91).

3. The vertical heat recovery coke oven waste heat power generation system according to claim 2, characterized in that, The condensation deaerator pipeline (70) includes an exhaust pipe (71), a condensing device (72), a condensate pipe (73), a heater (74), a deaerator (75), and a water supply pipe (78); the exhaust pipe (71) is connected to the exhaust port of the low-pressure cylinder (32) and the inlet of the condensing device (72), respectively; the condensate pipe (73) is connected to the outlet of the condensing device (72) and the inlet of the deaerator (75), respectively; the water supply pipe (78) The outlet of the deaerator (75) and the inlet of the economizer (11) are connected; along the water flow direction of the condensate pipe (73), the heater (74) and the deaerator (75) are sequentially arranged on the condensate pipe (73); the first bypass (91) is connected to the high-temperature reheat steam pipeline (60) and the exhaust pipe (71); the low-pressure cylinder (32) provides non-adjustable extraction steam to the heater (74) and the deaerator (75) respectively.

4. The vertical heat recovery coke oven waste heat power generation system according to claim 3, characterized in that, The heater (74) includes a first low-pressure heater (741) and a second low-pressure heater (742); along the water flow direction of the condensate pipe (73), the second low-pressure heater (742) and the first low-pressure heater (741) are sequentially arranged in the condensate pipe (73) and located between the deaerator (75) and the condenser (72).

5. The vertical heat recovery coke oven waste heat power generation system according to claim 4, characterized in that, The condensate deaeration pipeline (70) includes a shaft seal heater (79). Along the water flow direction of the condensate pipe (73), the shaft seal heater (79), the second low-pressure heater (742), and the first low-pressure heater (741) are sequentially arranged in the condensate pipe (73) and located between the deaerator (75) and the condensing device (72). The condensate deaeration pipeline (70) includes a condensate pump (76), which is arranged in the condensate pipe (73) and located between the shaft seal heater (79) and the condensing device (72).

6. The vertical heat recovery coke oven waste heat power generation system according to claim 4, characterized in that, The condensation deaeration pipeline (70) includes a boiler feedwater pump (77), which is installed in the feedwater pipe (78).

7. The vertical heat recovery coke oven waste heat power generation system according to claim 1, characterized in that, The high-pressure bypass device (80) includes a second bypass (81) and a second valve (82); the second bypass (81) connects the main steam pipeline (40) and the low-temperature reheat steam pipeline (50), and the second valve (82) is located in the second bypass (81).

8. The vertical heat recovery coke oven waste heat power generation system according to claim 1, characterized in that, The superheater (13) includes a low-temperature superheater (131) and a high-temperature superheater (132); the reheater (14) includes a low-temperature reheater (141) and a high-temperature reheater (142); along the flow direction of the high-temperature flue gas in the waste gas boiler (10), the high-temperature superheater (132), the high-temperature reheater (142), the low-temperature superheater (131), the low-temperature reheater (141), the evaporator (12), and the economizer (11) are arranged in sequence, and the economizer (11), the evaporator (12), the low-temperature superheater (131), and the high-temperature superheater (132) are used to heat the feedwater entering the waste gas boiler (10) in sequence, and the low-temperature reheater (141) and the high-temperature reheater (142) are used to heat the steam from the low-temperature reheat steam pipeline (50) in sequence.

9. The vertical heat recovery coke oven waste heat power generation system according to claim 8, characterized in that, The steam pressure output by the high-temperature superheater (132) is P1, the temperature is T1, 13.7MPa≤P1<16.7MPa, and 560℃<T1≤610℃.

10. The vertical heat recovery coke oven waste heat power generation system according to claim 8, characterized in that, The steam pressure output by the high-temperature superheater (132) is P2, the temperature is T2, 16.7MPa≤P2<22.1MPa, and 560℃<T2≤610℃.

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