Coke oven flue gas waste heat recovery power generation system and process

Abstract

The invention relates to a coke oven flue gas waste heat recovery power generation system and process, and the system comprises a coke oven flue gas waste heat recovery unit and an organic Lamberkine cycle power generation unit; the coke oven flue gas waste heat recovery unit consists of a flue gas source flue, a waste heat recovery flue, a flue gas heat exchanger, a flue gas fan, a chimney and a bypass flue; the organic Lamberkine cycle power generation unit consists of a working medium expansion machine, a power generator, a power generation grid-connected cabinet, a working medium condenser and a working medium pump; coke oven flue gas with the temperature of about 210 DEG C is subjected to heat exchange and cooling through the flue gas heat exchanger, then pressurized through the fan, led to the chimney and discharged to the atmosphere, and waste heat recovery of the coke oven flue gas is completed; heat of coke oven flue gas in the flue gas heat exchanger is converted into the organic working medium, the high-temperature organic working medium expands in the working medium expansion machine to do work, then the power generator is driven to generate power, and energy conversion and utilization are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of coke oven waste heat recovery and utilization, and in particular to a coke oven flue gas waste heat recovery power generation system and process using an organic Rankine cycle. Background Art

[0002] In the coking process, the coke oven flue gas is the waste gas generated after the combustion and heat exchange of the heated coal gas. The heat it brings out accounts for about 17% of the heat input of the coking production. If it is directly discharged into the atmosphere without purification and heat recovery, it will cause energy loss and environmental pollution. The waste heat of the coke oven flue gas belongs to low-grade calorific value waste heat. Although the flue gas temperature range of different forms of coking ovens is different, most of them are below 270℃ or even lower, which is not easy to recycle.

[0003] Heat recovery from coke oven flue gas is very important for reducing energy consumption in the coking process and reducing comprehensive carbon emissions. At present, the mainstream method for recovering waste heat from coke oven flue gas is to use waste heat boilers to produce hot water or low-pressure saturated steam and incorporate it into the steam network.

[0004] For example, a "coke oven flue gas waste heat recovery device" disclosed in a Chinese utility model patent with publication number CN204373429U includes a flue gas system part, a steam-water system part and a power generation system part. The flue gas of the coke oven flue gas part is successively introduced into the chimney through the heat pipe waste heat boiler and the economizer by the induced draft fan for discharge; the industrial water of the steam-water system part is sent to the economizer after softening and deoxygenation treatment, and then heat exchanged with the flue gas from the heat pipe waste heat boiler is carried out in the steam drum of the heat pipe waste heat boiler to separate the steam and water to produce 0.7-1.0MPa saturated steam; the steam after steam-water separation enters the power generation system part for power generation, so that the saturated steam is reduced in pressure to 0.3-0.5MPa.

[0005] However, for coking plants, the overall demand for hot water and low-pressure steam is not large, and the hot water and steam produced by utilizing waste heat from other production processes can already meet the needs of hot water and steam users. Therefore, it is necessary to explore a feasible method that can efficiently recover the waste heat of coke oven flue gas, and at the same time, the recovered energy can be more directly used by users. Summary of the invention

[0006] The present invention provides a coke oven flue gas waste heat recovery power generation system and process, wherein the coke oven flue gas with a temperature of about 210°C is cooled by heat exchange in a flue gas heat exchanger, and then pressurized by a fan and led to a chimney for discharge into the atmosphere, thereby completing the waste heat recovery of the coke oven flue gas; the heat of the coke oven flue gas in the flue gas heat exchanger is converted into an organic working fluid, and the high-temperature organic working fluid expands and performs work in a working fluid expander, thereby driving a generator to generate electricity, thereby realizing energy conversion and utilization.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A coke oven flue gas waste heat recovery power generation system comprises a coke oven flue gas waste heat recovery unit and an organic Langken cycle power generation unit; the coke oven flue gas waste heat recovery unit comprises a flue gas source flue, a waste heat recovery flue, a flue gas heat exchanger, a flue gas fan, a chimney and a bypass flue; the flue gas source flue is connected to the flue gas heat exchanger, the flue gas fan and the chimney in sequence through the waste heat recovery flue, and the flue gas source flue is directly connected to the chimney through the bypass flue; a waste heat recovery unit inlet gate is arranged on the waste heat recovery flue close to the flue gas source flue; a bypass flue close to the flue gas source flue is provided with a bypass flue damper; a waste heat recovery unit outlet damper is arranged on the waste heat recovery flue near the chimney; the flue gas heat exchanger is a radial heat pipe heat exchanger; the organic Langken cycle power generation unit is composed of a working fluid expander, a generator, a power generation grid cabinet, a working fluid condenser and a working fluid pump; the organic working fluid outlet of the flue gas heat exchanger is connected to the organic working fluid inlet of the flue gas heat exchanger through an organic working fluid circulation pipeline; a working fluid expander, a working fluid condenser and a working fluid pump are arranged in sequence on the organic working fluid circulation pipeline along the flow direction of the organic working fluid; the working fluid expander is also connected to a generator, and the generator is connected to the external power grid through the power generation grid cabinet.

[0009] Furthermore, the flue gas heat exchanger is composed of a shell and a heat exchange element, one end of the shell is the flue gas inlet end, and the other end is the flue gas outlet end; the interior of the shell is divided into a preheating section, an evaporation section and a superheating section in the direction from the flue gas outlet end to the flue gas inlet end; the heat exchange element is composed of an inlet header, an internal coil, and an outlet header; the inlet header and the outlet header are both arranged vertically with the internal coil; the inlet header is arranged close to the flue gas outlet end, and the outlet header is arranged close to the flue gas inlet end; the internal coil is a radial heat exchange tube, which is composed of a heat exchange tube body and a jacket structure, and the jacket structure is filled with liquid working fluid.

[0010] Furthermore, the internal coil is composed of multiple rows and columns of radial heat exchange tubes, and two adjacent radial heat exchange tubes are connected via elbows.

[0011] Furthermore, an expander inlet filter is provided on the organic working fluid circulation pipeline upstream of the working fluid expander, and a working fluid pump inlet filter is provided on the organic working fluid circulation pipeline upstream of the working fluid pump.

[0012] Furthermore, the waste heat recovery unit inlet damper, the bypass flue damper and the waste heat recovery unit outlet damper are interlocked and controlled by a control system.

[0013] A coke oven flue gas waste heat recovery power generation process comprises the following steps:

[0014] 1) The coke oven flue gas with a temperature below 210°C after dust removal is introduced into the coke oven flue gas waste heat recovery unit through the flue gas source flue; the inlet damper of the waste heat recovery unit is opened, the bypass flue damper is closed, and the outlet damper of the waste heat recovery unit is opened; the coke oven flue gas enters the flue gas heat exchanger for heat exchange, and the heat is taken away by the organic working fluid; the coke oven flue gas whose temperature is reduced to below 165°C after heat exchange is pressurized by the flue gas fan and discharged to the atmosphere through the chimney;

[0015] 2) In the organic Langken cycle power generation unit, the high-temperature organic working fluid after heat exchange with the coke oven flue gas is filtered and then enters the working fluid expander, pushing the working fluid expander to do work, and then driving the generator to generate electricity, and the electric energy is sent to the external power grid through the power generation grid cabinet; the expanded organic working fluid is sent to the working fluid condenser, and becomes liquid organic working fluid after cooling and condensation. The liquid organic working fluid enters the working fluid pump after filtering, and is pressurized by the working fluid pump and sent to the flue gas heat exchanger for heat exchange with the coke oven flue gas, completing the cycle of the organic working fluid.

[0016] Furthermore, when the coke oven flue gas waste heat recovery unit fails or is shut down for maintenance, the inlet gate of the waste heat recovery unit is closed, the bypass flue gate is opened, and the outlet gate of the waste heat recovery unit is closed; the coke oven flue gas in the flue gas source flue is directly introduced into the chimney through the bypass flue for discharge.

[0017] Furthermore, the organic working fluid is pentafluoropropane.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1) The waste heat from low-grade coke oven flue gas is converted into high-grade energy;

[0020] 2) Set up a safety interlock mechanism to ensure continuous and stable operation of the system;

[0021] 3) The flue gas heat exchanger uses radial heat pipe forced circulation, which has better stability and safety than the heat exchanger using conventional natural circulation, higher circulation rate and higher thermal efficiency;

[0022] 4) The organic working fluid circulating in the organic Langken cycle power generation unit is preferably pentafluoropropane with a low boiling point, which can be vaporized at a lower temperature; for the coke oven flue gas with a low calorific value, the waste heat recovery efficiency is higher and the recovery capacity is stronger under the premise of meeting the work requirements of the generator;

[0023] 5) The flue gas heat exchanger adopts a steam drum-free design, which has a more compact structure and lower manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a coke oven flue gas waste heat recovery power generation system according to the present invention.

[0025] Figure 2a It is a structural schematic diagram of the flue gas heat exchanger of the present invention.

[0026] Figure 2b The structure of the heat exchange element in the flue gas heat exchanger of the present invention is schematically shown. Figure 1 ( Figure 2a side view).

[0027] Figure 2c Schematic diagram of the structure of the heat exchange element in the flue gas heat exchanger of the present invention ( Figure 2a looking down).

[0028] Figure 3 It is a schematic diagram of the principle of the flue gas heat exchanger of the present invention.

[0029] In the figure: Ⅰ. Coke oven flue gas waste heat recovery unit Ⅱ. Organic Langken cycle power generation unit 1. Flue gas source flue 2. Flue gas heat exchanger inlet flue 3. Flue gas heat exchanger outlet flue 4. Flue gas fan outlet flue 5. Bypass flue 6. Waste heat recovery unit inlet gate 7. Flue gas heat exchanger 71. Radial heat exchange tube 72. Jacket structure 73. Inlet header 74. Outlet header A. Preheating section B. Evaporation section C. Superheating section 8. Flue gas fan 9. Waste heat recovery unit outlet gate 10. Chimney 11. Bypass flue gate 12. Expander inlet filter 13. Working fluid expander 14. Generator 15. Power generation grid cabinet 16. Working fluid condenser 17 Working fluid pump inlet filter 18. Working fluid pump 19. Organic working fluid outlet pipe 20. Organic working fluid inlet pipe 21. Cooling water inlet pipe 22. Cooling water return pipe DETAILED DESCRIPTION

[0030] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0031] like Figure 1 As shown, the coke oven flue gas waste heat recovery and power generation system described in the present invention is a process system that uses an organic Rankine cycle to recover the coke oven flue gas waste heat and generate electricity. It is also a process system that stably and efficiently converts low-grade coke oven flue gas waste heat into high-grade energy.

[0032] The coke oven flue gas waste heat recovery power generation system described in the present invention comprises two subsystems: a coke oven flue gas waste heat recovery unit I and an organic Rankine cycle power generation unit II. Among them:

[0033] The coke oven flue gas waste heat recovery unit I consists of a flue gas source flue 1, a waste heat recovery flue, a flue gas heat exchanger 7, a flue gas fan 8, a chimney 10 and a bypass flue 5; the waste heat recovery flue further includes a flue gas heat exchanger inlet flue 2, a flue gas heat exchanger outlet flue 3 and a flue gas fan outlet flue 4.

[0034] The organic Rankine cycle power generation unit II is composed of a working fluid expander 13, a generator 14, a power generation grid cabinet 15, a working fluid condenser 16 and a working fluid pump 18, and also includes an expander inlet filter 12, a working fluid pump inlet filter 17, an organic working fluid outlet pipe 19, an organic working fluid inlet pipe 29, a cooling water inlet pipe 21 and a cooling water return pipe 22, etc.

[0035] like Figure 2a-2c As shown, the flue gas heat exchanger 7 consists of a shell and a heat exchange element, one end of the shell is the flue gas inlet end, and the other end is the flue gas outlet end; the interior of the shell is divided into a preheating section A, an evaporation section B and a superheating section C in the direction from the flue gas outlet end to the flue gas inlet end; the heat exchange element consists of an inlet header 73, an internal coil, and an outlet header 74; the inlet header 73 and the outlet header 74 are both arranged perpendicular to the internal coil; the inlet header 73 is arranged close to the flue gas outlet end, and the outlet header 74 is arranged close to the flue gas inlet end; the internal coil is a radial heat exchange tube 71, which consists of a heat exchange tube body and a jacket structure 72, and the jacket structure 72 is filled with liquid working medium.

[0036] like Figure 3 As shown, the working principle of the flue gas heat exchanger 7 is as follows:

[0037] Gas side: The flue gas heat exchanger 7 is placed vertically or horizontally, and the high-temperature flue gas enters from the flue gas inlet, passes through the superheating section C, the evaporation section B, and the preheating section A in sequence, and finally flows out from the flue gas outlet. The superheating section C, the evaporation section B, and the preheating section A are connected in series through elbows.

[0038] Medium side: The superheating section C, the evaporating section B and the preheating section A in the flue gas heat exchanger 7 have the same structure, and all include radial heat exchange tubes (or enhanced heat transfer tubes).

[0039] When the coke oven flue gas enters the flue gas heat exchanger 7 and flows through the internal coil, it transfers heat to the liquid working medium in the jacket structure. The liquid working medium absorbs heat and vaporizes, transferring heat to the organic working medium in the heat exchange tube body. After the heat exchange, the liquid working medium condenses into liquid again. This repeated absorption and release of heat completes the heat exchange process between the coke oven flue gas and the organic working medium.

[0040] The organic working fluid first enters the flue gas heat exchanger 7 through the organic working fluid circulation pipeline, is distributed to each radial heat exchange tube through the inlet header 73, and is heated by the liquid working fluid in the jacket structure that has been heated by the coke oven flue gas. That is, the heat of the flue gas is transferred to the organic working fluid through the liquid working fluid. The organic working fluid that has absorbed the heat is collected in the outlet header 74 and enters the organic working fluid circulation pipeline, and then drives the working fluid expander 13 to do work, and then drives the generator 14 to generate electricity. The above process is repeated.

[0041] In conventional radial tube heat exchangers, the circulation method used is usually a natural circulation method with a steam drum. In the flue gas heat exchanger 7 of the present invention, the steam drum required in conventional natural circulation is eliminated, and forced circulation is performed by the working fluid pump 18, so that the internal structure of the system is simpler, the height of the pipeline is not limited by the steam drum, the weight of the equipment and the auxiliary support structure are greatly reduced, and the investment cost is reduced. The forced circulation greatly increases the circulation rate of the organic working fluid, thereby making the heat utilization rate higher and enhancing the safety and stability of the equipment operation.

[0042] In the present invention, after dust removal, the coke oven flue gas enters the coke oven flue gas waste heat recovery unit I through the flue gas source flue 1, and the temperature of the coke oven flue gas entering the coke oven flue gas waste heat recovery unit I is about 210°C. When the system is operating normally, the inlet gate 6 of the waste heat recovery unit is opened, the bypass flue gate 11 is closed, and the outlet gate 9 of the waste heat recovery unit is opened. The coke oven flue gas in the flue gas source flue 1 enters the flue gas heat exchanger 7 through the flue gas heat exchanger inlet flue 2. The temperature of the flue gas after heat exchange is reduced to below 165°C, and its heat is taken away by the organic working medium. After completing the heat exchange and cooling, the coke oven flue gas is led out from the flue gas heat exchanger outlet flue 3, pressurized by the flue gas fan 8, and discharged into the atmosphere after entering the chimney 10 through the flue gas fan outlet flue 4.

[0043] When the coke oven flue gas waste heat recovery unit is not operating normally (failure or maintenance), the waste heat recovery unit inlet damper 6 is closed, the bypass flue damper 11 is opened, and the waste heat recovery unit outlet damper 9 is closed. The coke oven flue gas in the flue gas source flue is directly introduced into the chimney 10 without cooling and heat exchange, and discharged to the atmosphere through the suction of the chimney 10.

[0044] The organic working fluid circulating in the organic Rankine cycle power generation unit II of the present invention is heated by the flue gas heat exchanger 7 to generate superheated steam, which is filtered by the expander inlet filter 12 and enters the working fluid expander 13, driving the working fluid expander 13 to do work, thereby driving the generator 14 to generate electricity. The electric energy generated by the generator 14 is sent to the external power grid through the power generation grid cabinet 15. The organic working fluid coming out of the working fluid expander 13 is sent to the working fluid condenser 16 for cooling and condensation, and then becomes liquid at 35°C again. The condensed organic working fluid is filtered by the working fluid pump inlet filter 17 and enters the working fluid pump 18. The working fluid pump 18 pressurizes the low-temperature liquid organic working fluid and sends it back to the flue gas heat exchanger 7 for heating, completing the circulation of the organic working fluid.

[0045] In order to make the purpose, technical scheme and technical effect of the present invention clearer, the technical scheme in the embodiment of the present invention is now clearly and completely described. However, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. In combination with the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] [Example]

[0047] like Figure 1 As shown, in this embodiment, the coke oven flue gas waste heat recovery power generation system includes a coke oven flue gas waste heat recovery unit I and an organic Rankine cycle power generation unit II. Among them:

[0048] The coke oven flue gas waste heat recovery unit I comprises a hot flue gas source flue 1, a flue gas heat exchanger inlet flue 2, a flue gas heat exchanger outlet flue 3, a flue gas fan outlet flue 4, a bypass flue 5, a waste heat recovery unit inlet damper 6, a flue gas heat exchanger 7, a flue gas fan 8, a waste heat recovery unit outlet damper 9, a chimney 10, a bypass flue damper 11, etc.

[0049] The organic Rankine cycle power generation unit II includes a working fluid expander inlet filter 12, a working fluid expander 13, a generator 14, a power generation grid cabinet 15, a working fluid condenser 16, a working fluid pump inlet filter 17, a working fluid pump 18, an organic working fluid outlet pipe 19, an organic working fluid inlet pipe 20, a cooling water inlet pipe 21, a cooling water return pipe 22, etc.

[0050] Taking the typical coke oven working condition as an example, the coke oven flue gas temperature at the inlet of the coke oven flue gas waste heat recovery unit I is about 210℃, and the flue gas flow rate is about 400000Nm 3 / h, the main components of coke oven flue gas are CO2, H2O, N2, and O2, and the volume fractions of the above components are 4.18, 13.58%, 72.64%, and 9.6%, respectively.

[0051] When the coke oven flue gas waste heat recovery power generation system operates normally, the waste heat recovery unit inlet damper 6 is opened, the bypass flue damper 11 is closed, and the waste heat recovery unit outlet damper 9 is opened. The coke oven flue gas in the flue gas source flue 1 enters the flue gas heat exchanger 7 through the flue gas heat exchanger inlet flue 2. After heat exchange, the temperature drops to 165°C and is discharged from the flue gas heat exchanger outlet flue 3. After being pressurized by the flue gas fan 8, it is introduced into the chimney 10.

[0052] According to calculation, in this embodiment, the waste heat recovered per unit volume of coke oven flue gas is 61.6 kJ / Nm 3, combined with the flue gas volume and considering the heat exchange efficiency, the waste heat recovery heat achieved by the flue gas heat exchanger 7 is 61.6×400000×0.96=23654400 kJ / h, i.e. 6571 kW.

[0053] On the other hand, the organic working fluid enters the flue gas heat exchanger 7 for heat exchange, enters the working fluid expander inlet filter 12 through the organic working fluid outlet pipe 19, enters the working fluid expander 13 after filtration to perform work, and further drives the generator 14 to generate electricity, and the generated electric energy is sent to the external power grid through the power generation grid cabinet 15. The expanded organic working fluid is condensed into liquid through the working fluid condenser 16 for heat exchange, enters the working fluid pump 18 after filtration through the working fluid pump inlet filter 17, and is sent to the flue gas heat exchanger 7 for heat exchange through the organic working fluid inlet pipe 20 after pressurization, completing the organic Rankine cycle.

[0054] In this embodiment, considering that the comprehensive power generation efficiency of the organic Rankine cycle is about 13%, the electric energy sent to the power grid is about 6571×0.13=854 kW, that is, the energy obtained after waste heat recovery is 854 kW.

[0055] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A coke oven flue gas waste heat recovery power generation system, characterized in that: It includes a coke oven flue gas waste heat recovery unit and an organic Langken cycle power generation unit; the coke oven flue gas waste heat recovery unit is composed of a flue gas source flue, a waste heat recovery flue, a flue gas heat exchanger, a flue gas fan, a chimney and a bypass flue; the flue gas source flue is connected to the flue gas heat exchanger, the flue gas fan and the chimney in sequence through the waste heat recovery flue, and the flue gas source flue is directly connected to the chimney through the bypass flue; a waste heat recovery unit inlet damper is arranged on the waste heat recovery flue close to the flue gas source flue; a bypass flue damper is arranged on the bypass flue close to the flue gas source flue; An outlet gate of a waste heat recovery unit is arranged on the waste heat recovery flue of the chimney; the flue gas heat exchanger is a radial heat pipe heat exchanger; the organic Langken cycle power generation unit is composed of a working fluid expander, a generator, a power generation grid-connected cabinet, a working fluid condenser and a working fluid pump; the organic working fluid outlet of the flue gas heat exchanger is connected to the organic working fluid inlet of the flue gas heat exchanger through an organic working fluid circulation pipeline; a working fluid expander, a working fluid condenser and a working fluid pump are arranged in sequence on the organic working fluid circulation pipeline along the flow direction of the organic working fluid; the working fluid expander is also connected to a generator, and the generator is connected to an external power grid through a power generation grid-connected cabinet.

2. A coke oven flue gas waste heat recovery power generation system according to claim 1, characterized in that: The flue gas heat exchanger is composed of a shell and a heat exchange element, one end of the shell is the flue gas inlet end, and the other end is the flue gas outlet end; the interior of the shell is divided into a preheating section, an evaporation section and a superheating section in sequence from the flue gas outlet end to the flue gas inlet end; the heat exchange element is composed of an inlet header, an internal coil, and an outlet header; the inlet header and the outlet header are both arranged vertically with the internal coil; the inlet header is arranged close to the flue gas outlet end, and the outlet header is arranged close to the flue gas inlet end; the internal coil is a radial heat exchange tube, which is composed of a heat exchange tube body and a jacket structure, and the jacket structure is filled with liquid working medium.

3. A coke oven flue gas waste heat recovery power generation system according to claim 2, characterized in that: The internal coil is composed of multiple rows and columns of radial heat exchange tubes, and two adjacent radial heat exchange tubes are connected via elbows.

4. The coke oven flue gas waste heat recovery power generation system according to claim 1, characterized in that: An expander inlet filter is arranged on the organic working medium circulation pipeline upstream of the working medium expander, and a working medium pump inlet filter is arranged on the organic working medium circulation pipeline upstream of the working medium pump.

5. The coke oven flue gas waste heat recovery power generation system according to claim 1, characterized in that: The waste heat recovery unit inlet damper, the bypass flue damper and the waste heat recovery unit outlet damper are interlocked and controlled by a control system.

6. A coke oven flue gas waste heat recovery power generation process based on the system as claimed in any one of claims 1 to 5, characterized in that: The steps include: 1) The coke oven flue gas with a temperature below 210°C after dust removal is introduced into the coke oven flue gas waste heat recovery unit through the flue gas source flue; the inlet damper of the waste heat recovery unit is opened, the bypass flue damper is closed, and the outlet damper of the waste heat recovery unit is opened; the coke oven flue gas enters the flue gas heat exchanger for heat exchange, and the heat is taken away by the organic working fluid; the coke oven flue gas whose temperature is reduced to below 165°C after heat exchange is pressurized by the flue gas fan and discharged to the atmosphere through the chimney; 2) In the organic Langken cycle power generation unit, the high-temperature organic working fluid after heat exchange with the coke oven flue gas is filtered and then enters the working fluid expander, pushing the working fluid expander to do work, and then driving the generator to generate electricity, and the electric energy is sent to the external power grid through the power generation grid cabinet; the expanded organic working fluid is sent to the working fluid condenser, and becomes liquid organic working fluid after cooling and condensation. The liquid organic working fluid enters the working fluid pump after filtering, and is pressurized by the working fluid pump and sent to the flue gas heat exchanger for heat exchange with the coke oven flue gas, completing the cycle of the organic working fluid.

7. A coke oven flue gas waste heat recovery power generation process according to claim 6, characterized in that: When the coke oven flue gas waste heat recovery unit fails or is shut down for maintenance, the inlet gate of the waste heat recovery unit is closed, the bypass flue gate is opened, and the outlet gate of the waste heat recovery unit is closed; the coke oven flue gas in the flue gas source flue is directly introduced into the chimney through the bypass flue for discharge.

8. The coke oven flue gas waste heat recovery power generation process according to claim 6, characterized in that: The organic working fluid is pentafluoropropane.

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