Non-boiler dry quenching waste heat recovery and power generation system

Abstract

The invention discloses a boiler-free dry quenching waste heat recovery and power generation system, and belongs to the technical field of coking products.A main flue gas heat exchanger and an auxiliary flue gas heat exchanger are adopted for heat exchange in the dry quenching waste heat recovery process, and inert gas working media are introduced during heat exchange to recover flue gas waste heat; and meanwhile, a dry quenching afterburning process technical recipe is introduced, a power generation process taking an inert gas working medium as a power cycle is realized, the system has the characteristics of simple system, short process chain, accurate control and high recovery heat efficiency, and the risk of serious dangerous accidents caused by a large amount of water gas during pipe explosion of a boiler taking water as a working medium can be reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of coking production, and particularly relates to a waste heat recovery and power generation system for coke dry quenching without a boiler. Background Art

[0002] The waste heat power generation technology for coke dry quenching utilizes inert gases such as nitrogen to cool coke in a coke dry quenching furnace, and recovers the heat of the high-temperature flue gas from the coke dry quenching furnace. The heat is absorbed by a waste heat boiler for coke dry quenching to generate high-temperature and high-pressure steam, which is sent to a steam turbine generator set for power generation or industrial heat supply, converting thermal energy into electrical energy and mechanical energy.

[0003] For the waste heat recovery in the traditional coke dry quenching process, heat exchange is carried out through a boiler for coke dry quenching to drive a steam turbine for power generation. Once the boiler for coke dry quenching fails, the coke dry quenching production can only be stopped, and serious production failures or safety accidents may occur. Solving the problem of a large amount of water gas generated by the "tube burst" of the boiler for coke dry quenching and minimizing the operation risk is a major technical problem in the current coke dry quenching industry. Secondly, the traditional power generation system of the boiler for coke dry quenching adopts a Rankine cycle with water-steam as the working medium. The key equipment of this system includes boilers, steam turbine generator sets, condensate pumps, deaerators, boiler feed pumps, etc., and is equipped with chemical water treatment equipment, circulating cooling water facilities or air-cooled heat exchange equipment. It has the disadvantages of low system power generation efficiency, long process flow, complex structure, poor unit peak shaving ability, and large occupied space. In addition, due to the influence of coke pushing from the coke oven and the equipment of the downstream screening and coke conveying system on coke dry quenching production, the unplanned start-up and shutdown are uncertain, and the coke dry quenching production fluctuates greatly, often causing irreversible damage to the service life of the refractory materials and boilers for coke dry quenching. Therefore, in order to solve the many disadvantages of the traditional coke dry quenching production process, change the traditional waste heat recovery process for coke dry quenching, and adopt a production working medium with higher power generation efficiency, more compact equipment, and greater safety and reliability is the current research focus.

[0004] In the prior art, such as a method for realizing maintenance without stopping production of a boiler for coke dry quenching reported in Chinese Patent CN106867549B, this method introduces a heat exchange device into the flue gas circulation system of the original coke dry quenching furnace, primary dust collector, boiler for coke dry quenching, secondary dust collector, circulating fan and feed water preheater. When the coke dry quenching process system is in normal production, the heat exchange device does not participate in the coke dry quenching production. When the boiler for coke dry quenching needs to be maintained, the coke dry quenching furnace operates normally, the boiler for coke dry quenching is isolated from the coke dry quenching process system for maintenance, and the inert gas after primary dust removal is sent into the heat exchange device for heat exchange and then enters the secondary dust collector. This avoids the influence on coke dry quenching production when the boiler for coke dry quenching is shut down for maintenance. However, this method can only temporarily solve the influence of the shutdown of the boiler for coke dry quenching on coke dry quenching production, and the heat exchange device with water-steam as the working medium still has the risk of "tube burst", and does not fundamentally solve the disadvantages of the power generation system of the boiler for coke dry quenching.

[0005] For another example, a coke dry quenching system using supercritical carbon dioxide as a circulating gas cooling working medium reported in Chinese Patent CN117778032A. In this system, a carbon dioxide boiler is used in the waste heat boiler. During production, the circulating gas sequentially passes through the coke dry quenching furnace, the primary dust collector, the carbon dioxide boiler, the secondary dust collector, and the circulating fan, and then enters the coke dry quenching furnace again to form a cycle. In the carbon dioxide boiler, supercritical carbon dioxide is used as the cooling working medium for the coke dry quenching circulating gas. In the carbon dioxide boiler, the circulating gas exchanges heat with supercritical carbon dioxide. The coke dry quenching circulating gas is cooled, and the supercritical carbon dioxide is heated and then used for turbine work. Then, after cooling and pressurization, it is sent to the carbon dioxide boiler to form a cycle. This patent does not consider the uncertainty of unplanned startup and shutdown. The coke dry quenching production fluctuates greatly, and the drastic fluctuation of the flue gas temperature of the circulating gas causes irreversible damage to the service life of the refractory materials of the coke dry quenching and the carbon dioxide boiler. Summary of the Invention

[0006] The object of the present invention is to provide a boilerless coke dry quenching waste heat recovery and power generation system. In the coke dry quenching waste heat recovery process, a main flue gas heat exchanger and a low-temperature flue gas heat exchanger are used for heat exchange. When exchanging heat, an inert gas working medium is introduced to recover the waste heat of the flue gas. At the same time, a power generation process with the inert gas working medium as the power cycle is realized. It has the characteristics of simple system, short process chain, precise control, and high heat recovery efficiency, and can reduce the dangerous state of a large amount of water gas formation caused by the explosion of the boiler with water as the working medium.

[0007] The present invention is realized through the following technical solutions: A boilerless coke dry quenching waste heat recovery and power generation system includes a flue gas waste heat recovery unit and a power cycle unit. The flue gas waste heat recovery unit includes a primary dust collector, a main flue gas heat exchanger, a secondary dust collector, and a secondary flue gas heat exchanger connected in sequence. The primary dust collector and the secondary flue gas heat exchanger are respectively connected to the coke dry quenching furnace. The power cycle unit, the main flue gas heat exchanger, and the secondary flue gas heat exchanger all use an inert gas as the working medium. The power cycle unit includes a turbine, a regenerator, a pre-cooler, and a main compressor connected in sequence. The inlet of the turbine is connected to the working medium outlet of the main flue gas heat exchanger, the outlet of the turbine is connected to the hot side of the regenerator, and the outlet of the main compressor is connected to the working medium inlet of the main flue gas heat exchanger through pipelines via the cold side of the regenerator and the secondary flue gas heat exchanger respectively. Considering the operating conditions of coke dry quenching, a temperature reduction and pressure reduction device is arranged between the working medium outlet of the main flue gas heat exchanger and the pre-cooler, and a standby compressor is arranged between the pre-cooler and the secondary flue gas heat exchanger to realize the special technical know-how of continuous coke dry quenching production.

[0008] The main flue gas heat exchanger includes a high-temperature flue gas heat exchanger and a low-temperature flue gas heat exchanger. The inlet of the turbine is connected to the working medium outlet of the high-temperature flue gas heat exchanger; the outlet of the main compressor is connected to the working medium inlet of the high-temperature flue gas heat exchanger through a pipeline via the cold side of the regenerator, and the outlet of the main compressor is connected to the working medium inlet of the low-temperature flue gas heat exchanger through a pipeline via the auxiliary flue gas heat exchanger. The working medium outlet of the low-temperature flue gas heat exchanger is connected to the working medium inlet of the high-temperature flue gas heat exchanger.

[0009] A fuel supply mechanism for adjusting the flue gas temperature is provided between the coke dry quenching furnace and the primary dust collector, and a flue gas temperature sensor is provided in front of the flue gas inlet of the main flue gas heat exchanger. Precise control of the waste heat recovery from coke dry quenching is achieved.

[0010] The bottoms of the primary dust collector and the secondary dust collector are respectively connected to the inlet of the gas ash conveying device, and the outlet of the gas ash conveying device is connected to the ash bin.

[0011] A circulation fan is provided between the secondary dust collector and the auxiliary flue gas heat exchanger.

[0012] The working process of the flue gas waste heat recovery unit includes: sequentially passing the high-temperature flue gas from the coke dry quenching furnace through dust removal by the primary dust collector, heat exchange by the high-temperature flue gas heat exchanger, heat exchange by the low-temperature flue gas heat exchanger, dust removal by the secondary dust collector, and heat exchange by the auxiliary flue gas heat exchanger, and then returning it to the cooling chamber of the coke dry quenching furnace.

[0013] The working process of the power cycle unit includes: S1. The high-temperature and high-pressure inert gas working medium that absorbs the waste heat of the high-temperature flue gas in the high-temperature flue gas heat exchanger is sequentially sent to the turbine to do work, heat exchange on the hot side of the regenerator, temperature reduction in the pre-cooler, and pressure increase by the main compressor to obtain a high-pressure and low-temperature inert gas working medium. A part of the high-pressure and low-temperature inert gas working medium is sent to the high-temperature flue gas heat exchanger after heat exchange on the cold side of the regenerator, and another part of the high-pressure and low-temperature inert gas working medium is heat exchanged by the auxiliary flue gas heat exchanger and then sent to the low-temperature flue gas heat exchanger for heat exchange and temperature increase. After mixing with the working medium from the cold side heat exchange of the regenerator, it is sent to the high-temperature flue gas heat exchanger again; S2. The high-temperature and high-pressure inert gas working medium that absorbs the waste heat of the high-temperature flue gas in the high-temperature flue gas heat exchanger is sequentially passed through a temperature reduction and pressure reduction device, a pre-cooler, a standby compressor, and an auxiliary flue gas heat exchanger, and then sent to the low-temperature flue gas heat exchanger.

[0014] In the flue gas waste heat recovery unit, the flue gas temperature entering the high-temperature flue gas heat exchanger is controlled at 950 - 1000 °C by the fuel supply mechanism; the flue gas temperature after heat exchange by the high-temperature flue gas heat exchanger is 270 °C, the flue gas temperature after heat exchange by the low-temperature flue gas heat exchanger is 150 °C, and the flue gas temperature after heat exchange by the auxiliary flue gas heat exchanger is 120 - 130 °C.

[0015] In the power cycle unit, the temperature of the high-temperature and high-pressure inert gas working medium ≥ 566 °C, and the pressure is 21.9 MPa; the temperature of the low-temperature and low-pressure inert gas working medium ≤ 35 °C, and the pressure is 8 MPa; the temperature of the high-pressure and low-temperature inert gas working medium ≤ 35 °C, and the pressure is 21.9 MPa; In the power cycle unit, a part of the high-pressure and low-temperature inert gas working medium is heated to 240 °C with a pressure of 21.9 MPa after heat exchange on the cold side of the regenerator; another part of the high-pressure and low-temperature inert gas working medium has a temperature of 104 °C and a pressure of 22 MPa after heat exchange in the secondary flue gas heat exchanger, and then is heated to 240 °C with a pressure of 21.9 MPa after heat exchange in the low-temperature flue gas heat exchanger, and is mixed with the working medium after heat exchange on the cold side of the regenerator.

[0016] It should be noted that the inert gas working medium described in the present invention includes but is not limited to supercritical carbon dioxide gas, carbon dioxide gas, helium gas, etc.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The present invention adopts the coke dry quenching supplementary combustion process technology. Through the fuel supply mechanism, the inlet temperature of the high-temperature flue gas heat exchanger in the system can be increased and stabilized, so that the flue gas temperature is stabilized at 950 - 1000 °C, ensuring that the production load fluctuation of coke dry quenching is smaller. At the same time, the system is simple, the control is precise, the investment is small, and the thermal efficiency of the equipment is improved.

[0018] (2) The present invention uses an inert gas working medium to exchange heat with the high-temperature flue gas heat exchanger, the low-temperature flue gas heat exchanger, and the secondary flue gas heat exchanger respectively, realizing the process flow of using the inert gas working medium as a new power cycle for power generation or other industrial drive systems applied in the coke dry quenching waste heat recovery system. It has the characteristics of a simple system, a short process chain, a high recovery thermal efficiency, and significantly adapting to the production load fluctuation of coke dry quenching.

[0019] (3) By circulating the inert gas working medium in the coke dry quenching flue gas heat exchanger, the present invention significantly reduces serious accidents such as explosion and combustion caused in the coke dry quenching furnace and the dust removal system after the traditional boiler tube explosion of coke dry quenching. The influence range is small, and the coke dry quenching production is safer.

[0020] (4) In the power cycle system with an inert gas as the working medium, the present invention designs a desuperheating and pressure-reducing device. When the unit fails or undergoes major repairs, the high-temperature and high-pressure inert gas working medium can be desuperheated and depressurized to a low-temperature and low-pressure gas working medium and enter the pre-cooler, and then the working medium circulation is realized through the standby compressor, ensuring the continuity of coke dry quenching production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic process flow diagram of the system of the present invention.

[0022] Among them, 1 is a coke dry quenching chamber, 2 is a primary dust collector, 3 is a main flue gas heat exchanger, 301 is a high-temperature flue gas heat exchanger, 302 is a low-temperature flue gas heat exchanger, 4 is a circulation fan, 5 is a secondary dust collector, 6 is a secondary flue gas heat exchanger, 7 is a turbine, 8 is a recuperator, 9 is a pre-cooler, 10 is a main compressor, 11 is a desuperheating and pressure-reducing device, 12 is a standby compressor, 13 is a fuel supply mechanism, 14 is a gas ash conveying device, and 15 is an ash bin. Detailed implementation manners

[0023] The invention objectives, technical solutions and beneficial effects of the present invention will be further described in detail below.

[0024] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further descriptions of the claimed present invention. Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0025] To solve the problems of coke dry quenching boiler failures and minimize operation risks, the present invention not only provides a flue gas heat exchanger using inert gas as the working medium to realize the flue gas waste heat recovery process, but also provides a power generation process using inert gas working medium as the power cycle. Specifically, by setting a flue gas heat exchange system using inert gas as the working medium in the coke dry quenching process system, the flue gas heat exchange system is composed of a main flue gas heat exchanger 3 and a secondary flue gas heat exchanger 6. The inert gas working medium exchanges heat with the high-temperature flue gas after passing through the primary dust collector 2 in the main flue gas heat exchanger 3. After the temperature of the flue gas is reduced, it is dusted by the secondary dust collector 5 and pressurized by the circulation fan 4, and then the temperature of the flue gas is further reduced by the secondary flue gas heat exchanger 6 and returned to the coke dry quenching chamber 1 for circulating cooling of the red coke. Secondly, since the inert gas working medium absorbs heat in the main flue gas heat exchanger 3 of the coke dry quenching, the high-temperature and high-pressure inert gas working medium enters the turbine 7 to expand and do work, so as to perform industrial drive or power generation. Among them, the exhaust working medium of the turbine 7 releases heat through the pre-cooler 9 and is pressurized by the main compressor 10 and exchanges heat with the recuperator 8, and then is sent back to the secondary flue gas heat exchanger 6 for preheating and the main flue gas heat exchanger 3 to complete the coke dry quenching waste heat recovery and power generation cycle.

[0026] In the present invention, since there is no dry-wet state conversion in the coke dry quenching flue gas heat exchanger and the ramp rate of the turbine 7 group is high, the influence range after the coke dry quenching production failure can be significantly reduced, making the coke dry quenching production safer. For the actual process system, it has the advantages of compact equipment, small floor area, flexible configuration of water cooling and air cooling, and energy saving.

[0027] To overcome the influence of the production load fluctuation of coke dry quenching on the waste heat recovery of the coke dry quenching flue gas heat exchanger, the present invention adopts the coke dry quenching supplementary combustion process technology. When the production load of coke dry quenching fluctuates, the fuel supply mechanism 13 is used to increase the inlet temperature of the main flue gas heat exchanger 3 of coke dry quenching, and it is stabilized in the range of 950 - 1000 °C. So that the inert gas working medium is heated at a constant pressure in the main flue gas heat exchanger 3, and the temperature can reach 566 °C or even higher before entering the turbine 7. Of course, under the allowable conditions of the turbine's sliding pressure operation, the coke dry quenching supplementary combustion system can be flexibly withdrawn. In order to fully absorb the heat of the high-temperature circulating flue gas in the coke dry quenching system, for the main flue gas heat exchanger 3 of the present invention, a high-temperature flue gas heat exchanger 301 and a low-temperature flue gas heat exchanger 302 are designed to be arranged successively from top to bottom. The high-temperature flue gas heat exchanger 301 and the low-temperature flue gas heat exchanger 302 are used for the recovery of flue gas thermal energy, with inert gas as the working medium, and the thermal energy is converted into mechanical energy and electrical energy.

[0028] In summary, the technical advantages of the present invention can be further summarized as follows: As described in the present invention, using the power cycle of the inert gas working medium to replace the traditional Rankine power cycle with water and steam as the working medium can increase the power generation efficiency by 3 - 5%, adapt to the production load fluctuation of coke dry quenching, and the adjustment rate is 3 - 4 times that of the traditional steam turbine unit.

[0029] As described in the present invention, the equipment is compact and occupies a small area. The turbine 7 is used for power generation. The turbine 7 is 1 / 10 of the traditional steam turbine, and the flue gas heat exchanger also has a volume smaller than that of the traditional waste heat boiler.

[0030] As described in the present invention, using the flue gas recovery system to replace the traditional coke dry quenching boiler and using the inert gas working medium as the power cycle can greatly reduce the risk of explosion of the coke dry quenching furnace 1 and the dust removal system caused by the "pipe burst" of the coke dry quenching boiler, and the safety of the coke dry quenching process system is significantly improved.

[0031] As described in the present invention, due to the adoption of the high-temperature flue gas heat exchanger 301, the low-temperature flue gas heat exchanger 302 and the auxiliary flue gas heat exchanger 6, the waste heat of the high-temperature flue gas can be recovered as much as possible, and the energy-saving effect is remarkable.

[0032] As described in the present invention, the main flue gas heat exchanger 3 with inert gas as the working medium has strong adaptability to the variable working conditions of coke dry quenching production, and solves the problem of "insufficient water circulation power" of the boiler with water and steam as the working medium at low load.

[0033] As described in the present invention, the working medium of the inert gas is not limited to carbon dioxide, helium, etc.

[0034] As described in the present invention, the primary dust collector adopts a dust collector using the cyclone separation principle, and is not limited to also adopting a dust collector using the gravity dust removal principle, etc.

[0035] The present invention will be further described in detail below in conjunction with embodiments, but the implementation manners of the present invention are not limited thereto. Embodiment

[0036] This embodiment relates to a boilerless coke dry quenching waste heat recovery and power generation system, which is mainly applied to the waste heat recovery and power generation system of coke dry quenching flue gas, such as Figure 1 As shown, it mainly includes equipment such as a primary dust collector 2, a high-temperature flue gas heat exchanger 301, a low-temperature flue gas heat exchanger 302, a secondary dust collector 5, a circulation fan 4, a by-pass flue gas heat exchanger 6, a turbine 7, a regenerator 8, a pre-cooler 9, a main compressor 10, a standby compressor 12, etc., and specifically realizes the following process circulation flow: (1) Circulation flow of flue gas waste heat recovery Coke dry quenching furnace 1 - Primary dust collector 2 - High-temperature flue gas heat exchanger 301 - Low-temperature flue gas heat exchanger 302 - Secondary dust collector 5 - Circulation fan 4 - By-pass flue gas heat exchanger 6 - Coke dry quenching furnace 1.

[0037] Specifically, the coke dry quenching furnace 1 sends high-temperature flue gas into the primary dust collector 2. After the flue gas removing particulate impurities passes through the high-temperature flue gas heat exchanger 301 and the low-temperature flue gas heat exchanger 302 for heat release twice, it enters the secondary dust collector 5. After the secondary dust collector 5 captures finer particulate dust in the flue gas, the circulation fan 4 is used to send the flue gas into the by-pass flue gas heat exchanger 6, and the flue gas temperature is further reduced, and finally it is sent back to the cooling chamber of the coke dry quenching furnace 1 to realize the circulation of flue gas waste heat recovery.

[0038] The bottoms of the primary dust collector 2 and the secondary dust collector 5 are respectively connected to the inlets of the gas ash conveying device 14, and the outlet of the gas ash conveying device 14 is then connected to the ash bin 15 to realize the collection of particulate impurities and dust in the flue gas.

[0039] (2) Power circulation flow of inert gas working medium (during normal production) a. High-temperature and high-pressure inert gas working medium - Turbine 7 - Regenerator 8 (hot side) - Pre-cooler 9 - Main compressor 10 - Regenerator 8 (cold side) - High-temperature flue gas heat exchanger 301 - High-temperature and high-pressure inert gas working medium; b. High-temperature and high-pressure inert gas working medium - Turbine 7 - Regenerator 8 (hot side) - Pre-cooler 9 - Main compressor 10 - By-pass flue gas heat exchanger 6 - Low-temperature flue gas heat exchanger 302 - High-temperature flue gas heat exchanger 301 - High-temperature and high-pressure inert gas working medium.

[0040] Specifically, the high-temperature flue gas after the primary deduster 2 of the coke dry quenching furnace 1 first enters the high-temperature flue gas heat exchanger 301. The high-temperature flue gas heat exchanger 301 uses an inert gas working medium for heat exchange to obtain a high-temperature and high-pressure inert gas working medium, which is discharged from the outlet of the high-temperature flue gas heat exchanger 301 and connected to the turbine 7 for power generation or other industrial drives. The inert gas working medium adiabatically expands and does work in the turbine 7. After the pressure and temperature of the working medium decrease, it enters the hot side of the regenerator 8 through a pipeline and exchanges heat with the inert gas working medium on the countercurrent cold side, so that the temperature of the cold side working medium is increased and the heat of the hot side working medium is utilized. The working medium coming out of the regenerator 8 after heat exchange enters the precooler 9 and is cooled by external cooling water or air. After releasing heat, a low-temperature and low-pressure inert gas working medium is obtained, and then it enters the main compressor 10 to be pressurized to obtain a high-pressure and low-temperature inert gas working medium. Part of the high-pressure and low-temperature inert gas working medium flows into the regenerator 8 from the cold side inlet of the regenerator 8. After the working medium absorbs heat, it is sent to the high-temperature flue gas heat exchanger 301 through the cold side outlet of the regenerator 8 and is used to recover the heat of the high-temperature flue gas again; another part of the high-pressure and low-temperature inert gas working medium is sent to the secondary flue gas heat exchanger 6 through a pipeline. The working medium absorbs the heat of the flue gas at the outlet of the circulation fan 4 in the secondary flue gas heat exchanger 6. After the temperature of the inert gas working medium rises, it enters the low-temperature flue gas heat exchanger 302. After the temperature of the inert gas working medium is further increased, it converges with the working medium from the cold side outlet of the regenerator 8 mentioned above, and finally enters the high-temperature heat exchanger. The inert gas working medium reaches the high-temperature and high-pressure outlet parameters and then enters the turbine 7 for power generation or other industrial drives.

[0041] (3) Power cycle process of the inert gas working medium (when the unit fails or is overhauled) A desuperheating and pressure-reducing device 11 and a standby compressor 12 are set. The inert gas working medium that absorbs the waste heat in the main flue gas heat exchanger 3 is successively passed through the desuperheating and pressure-reducing device 11, the precooler 9, the standby compressor 12 and the secondary flue gas heat exchanger 6, and then sent into the main flue gas heat exchanger 3 to realize the circulation of the inert gas working medium during the shutdown of the coke dry quenching, that is: High-temperature and high-pressure inert gas working medium - desuperheating and pressure-reducing device 11 - precooler 9 - standby compressor 12 - secondary flue gas heat exchanger 6 - low-temperature flue gas heat exchanger 302 - high-temperature flue gas heat exchanger 301 - high-temperature and high-pressure inert gas working medium.

[0042] Since the coke dry quenching production must be continuous, the coke dry quenching flue gas operates in a closed-loop system. When any equipment in the coke dry quenching system fails and shuts down, the coke dry quenching production needs to stop. Therefore, the coke dry quenching flue gas heat exchanger needs to be very safe and reliable. The equipment in the new power cycle system with inert gas as the working medium also needs to be safe and reliable. Since the main function of coke dry quenching is to quench coke and the waste heat recovery is secondary, to ensure the safety temperature of the system and to enable the equipment in the system to guarantee the continuous production of coke dry quenching during equipment failure shutdown or major overhaul. In this embodiment, a desuperheating and pressure-reducing device 11 is specifically designed. When the unit fails or undergoes major overhaul, the high-temperature and high-pressure inert gas can be desuperheated and pressure-reduced to a low-temperature and low-pressure gas working medium and enter the pre-cooler 9, and then the working medium circulation is realized through the standby compressor 12.

[0043] In a possible embodiment, in order to ensure the waste heat utilization efficiency of coke dry quenching, multi-factor dynamic control is carried out on the flue gas temperature, flue gas flow rate, etc., to eliminate the influence of the production load fluctuation of coke dry quenching on the coke dry quenching flue gas heat exchanger and the power generation system. This embodiment adopts a coke dry quenching supplementary combustion process with special know-how and mixes it with the high-temperature gas from the coke dry quenching furnace 1, which can increase the inlet temperature of the high-temperature flue gas heat exchanger 301 and stabilize it in the range of 950-1000 °C. Specifically, the coke dry quenching supplementary combustion process technology includes a gas fuel supply mechanism and pipeline, a flue gas temperature sensor for measuring the flue gas inhaled into the above-mentioned flue gas heat exchanger, etc., and controls the fuel supply amount through the above-mentioned supply mechanism based on the temperature of the above-mentioned temperature sensor, so as to be able to stabilize the flue gas temperature at the inlet of the high-temperature flue gas heat exchanger 301. Compared with the traditional coke dry quenching system, it can accurately control and stabilize the efficiency of the coke dry quenching flue gas heat exchanger.

[0044] During normal operation, high-temperature flue gas at 950 - 1000 °C enters the high-temperature flue gas heat exchanger 301. The temperature and pressure of the inert gas working medium discharged from the cold side outlet of the regenerator 8 are approximately 240 °C and 21.9 MPa. After mixing with the working medium discharged from the outlet of the low-temperature flue gas heat exchanger 302 (temperature and pressure are approximately 240 °C and 21.9 MPa), it enters the high-temperature flue gas heat exchanger 301, exchanges heat with the high-temperature flue gas entering the high-temperature flue gas heat exchanger 301, and the inert gas working medium is heated to reach 566 °C or higher and 21.9 MPa, then enters the turbine 7. The main compressor 10 sucks in the inert gas working medium at low temperature and low pressure (8 MPa, 35 °C) and compresses it to obtain the inert gas working medium at low temperature and high pressure (22 MPa, 35 °C). Among them, a part enters the secondary flue gas heat exchanger 6 to absorb the heat of the coke dry quenching flue gas in the secondary flue gas heat exchanger 6. The outlet temperature of the coke dry quenching flue gas is approximately 120 °C. The working medium (104 °C / 22 MPa) discharged from the outlet of the secondary flue gas heat exchanger 6 enters the low-temperature flue gas heat exchanger 302. After exchanging heat with the flue gas, the high-temperature and high-pressure working medium (240 °C / 21.9 MPa) is mixed with a part of the working medium from the regenerator 8 and then enters the high-temperature flue gas heat exchanger 301. After the high-temperature flue gas of coke dry quenching exchanges heat in the high-temperature flue gas heat exchanger 301, the outlet flue gas temperature is approximately 270 °C. After passing through the low-temperature flue gas heat exchanger 302, the flue gas temperature is approximately 150 °C, enters the coke dry quenching secondary dust collector 5, and then enters the coke dry quenching furnace 1 after being pressurized by the gas circulation fan 4 and cooled in the secondary flue gas heat exchanger 6.

[0045] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification or equivalent change made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A boiler-free coke dry quenching waste heat recovery and power generation system, characterized by: The invention comprises a flue gas waste heat recovery unit and a power circulation unit, wherein the flue gas waste heat recovery unit comprises a primary dust collector (2), a main flue gas heat exchanger (3), a secondary dust collector (5) and an auxiliary flue gas heat exchanger (6) which are connected in sequence, and the primary dust collector (2) and the auxiliary flue gas heat exchanger (6) are respectively connected to a dry quenching furnace (1). The power cycle unit, the main flue gas heat exchanger (3) and the auxiliary flue gas heat exchanger (6) all use inert gas as the working fluid. The power cycle unit comprises a turbine (7), a regenerator (8), a precooler (9) and a main compressor (10) which are connected in sequence. The air inlet of the turbine (7) is connected to the working fluid outlet of the main flue gas heat exchanger (3), the air outlet of the turbine (7) is connected to the hot side of the regenerator (8), and the air outlet of the main compressor (10) is connected to the working fluid inlet of the main flue gas heat exchanger (3) through pipelines via the cold side of the regenerator (8) and the auxiliary flue gas heat exchanger (6). A temperature and pressure reduction device (11) is provided between the working medium outlet of the main flue gas heat exchanger (3) and the precooler (9), and a compressor (12) is provided between the precooler (9) and the auxiliary flue gas heat exchanger (6).

2. The boiler-free CDQ waste heat recovery and power generation system according to claim 1 is characterized in that: The main flue gas heat exchanger (3) comprises a high-temperature flue gas heat exchanger (301) and a low-temperature flue gas heat exchanger (302); an air inlet of the turbine (7) is connected to a working fluid outlet of the high-temperature flue gas heat exchanger (301); an air outlet of the main compressor (10) is connected to a working fluid inlet of the high-temperature flue gas heat exchanger (301) via a pipeline through a cold side of a heat regenerator (8); an air outlet of the main compressor (10) is connected to a working fluid inlet of the low-temperature flue gas heat exchanger (302) via a pipeline through an auxiliary flue gas heat exchanger (6); and a working fluid outlet of the low-temperature flue gas heat exchanger (302) is connected to the working fluid inlet of the high-temperature flue gas heat exchanger (301).

3. The boiler-free CDQ waste heat recovery and power generation system according to claim 1 is characterized in that: A fuel supply mechanism (13) for adjusting the temperature of flue gas is provided between the dry quenching furnace (1) and the primary dust collector (2), and a flue gas temperature sensor is provided before the flue gas inlet of the main flue gas heat exchanger (3).

4. The boiler-free CDQ waste heat recovery and power generation system according to claim 1 is characterized in that: The bottoms of the primary dust collector (2) and the secondary dust collector (5) are respectively connected to the inlet of the gas ash conveying device (14), and the outlet of the gas ash conveying device (14) is connected to the ash bin (15).

5. The boiler-free CDQ waste heat recovery and power generation system according to claim 1 is characterized in that: A circulating fan (4) is provided between the secondary dust collector (5) and the auxiliary flue gas heat exchanger (6).

6. The boiler-free CDQ waste heat recovery and power generation system according to claim 2 is characterized in that: The working process of the flue gas waste heat recovery unit comprises: the high-temperature flue gas of the dry quenching furnace (1) is sequentially subjected to dust removal by a primary dust collector (2), heat exchange by a high-temperature flue gas heat exchanger (301), heat exchange by a low-temperature flue gas heat exchanger (302), dust removal by a secondary dust collector (5), heat exchange by an auxiliary flue gas heat exchanger (6), and then returned to the cooling chamber of the dry quenching furnace (1).

7. The boiler-free CDQ waste heat recovery and power generation system according to claim 6 is characterized in that: The working process of the power circulation unit includes: S1. The high-temperature and high-pressure inert gas working medium after absorbing the waste heat of the high-temperature flue gas in the high-temperature flue gas heat exchanger (301) is sequentially sent to the turbine (7) to perform work, the regenerator (8) to perform heat exchange on the hot side, the precooler (9) to reduce the temperature, and the main compressor (10) to increase the pressure to obtain the high-pressure and low-temperature inert gas working medium. A part of the high-pressure and low-temperature inert gas working medium is sent to the high-temperature flue gas heat exchanger (301) after heat exchange on the cold side of the regenerator (8), and the other part of the high-pressure and low-temperature inert gas working medium is sent to the low-temperature flue gas heat exchanger (302) after heat exchange and temperature increase, and is mixed with the working medium after heat exchange on the cold side of the regenerator (8) and then sent to the high-temperature flue gas heat exchanger (301); S2. The high-temperature and high-pressure inert gas working fluid that absorbs the waste heat of the high-temperature flue gas in the high-temperature flue gas heat exchanger (301) is sequentially passed through a temperature reduction and pressure reduction device (11), a precooler (9), a standby compressor (12) and an auxiliary flue gas heat exchanger (6), and then sent to a low-temperature flue gas heat exchanger (302).

8. The boiler-free CDQ waste heat recovery and power generation system according to claim 6 is characterized by: In the flue gas waste heat recovery unit, the temperature of the flue gas entering the high-temperature flue gas heat exchanger (301) is controlled to be 950-1000°C by the fuel supply mechanism (13); the temperature of the flue gas after heat exchange in the high-temperature flue gas heat exchanger (301) is 270°C, the temperature of the flue gas after heat exchange in the low-temperature flue gas heat exchanger (302) is 150°C, and the temperature of the flue gas after heat exchange in the auxiliary flue gas heat exchanger (6) is 120-130°C.

9. The boiler-free CDQ waste heat recovery and power generation system according to claim 6, characterized in that: In the power circulation unit, the temperature of the high-temperature and high-pressure inert gas working fluid is ≥566°C, and the pressure is 21.9MPa; the temperature of the low-temperature and low-pressure inert gas working fluid is ≤35°C, and the pressure is 8MPa; the temperature of the high-pressure and low-temperature inert gas working fluid is ≤35°C, and the pressure is 21.9MPa.

10. The boiler-free CDQ waste heat recovery and power generation system according to claim 9, characterized in that: In the power circulation unit, a portion of the high-pressure and low-temperature inert gas working fluid is heated by the cold side of the regenerator (8) to increase its temperature to 240°C and its pressure to 21.9 MPa; another portion of the high-pressure and low-temperature inert gas working fluid is heated by the auxiliary flue gas heat exchanger (6) to a temperature of 104°C and a pressure of 22 MPa, and then is heated by the low-temperature flue gas heat exchanger (302) to increase its temperature to 240°C and its pressure to 21.9 MPa, and is mixed with the working fluid after heat exchange from the cold side of the regenerator (8).

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