A coke oven raw gas waste heat recovery and utilization device

Abstract

The present invention discloses a coke oven raw gas waste heat recovery and utilization device, comprising a raw gas system and a steam-water system. The raw gas system comprises coke oven raw gas, a riser heat exchanger and an ammonia water spraying device. The raw gas flows through the inner cylinder of the riser heat exchanger through heat exchange and then enters the top pipe. The top pipe is connected to the ammonia water spraying device. The high-temperature and high-pressure water in the riser heat exchanger enters the steam-water system through a pipe. The steam-water system comprises a steam drum, a desalted water tank, a deaerator, a deaerator feed water pump, a steam drum feed water pump and a forced circulation pump that are interconnected. The process flow of the present invention is simple and reasonable, with automatic control and high safety. The riser heat exchanger has a simple structure, solves the problem of "fear of coking and blocking the riser", and has the ability to prevent "fear of dry burning and repeated water on and off". The double steam drum technology avoids dry burning of the riser heat exchanger, extends the service life of the riser heat exchanger, and ensures that saturated steam will not be interrupted.

Description

Technical Field

[0001] The present invention relates to the technical field of energy conservation and emission reduction in coking plants, and in particular to a device for recovering and utilizing waste heat from raw coal gas from a coke oven. Background Art

[0002] As an energy- and resource-intensive industry, the steel industry accounts for approximately 16% of China's total energy consumption, with energy consumption per ton of steel produced 20% higher than in developed countries. Therefore, in the context of global energy conservation and emission reduction, vigorously developing new technologies to promote low-energy steel production is of great significance. As a key production process in steel companies, coke oven production accounts for 7% to 8% of total energy consumption. During the coking process, 50 kilograms of standard coal are recycled for every ton of coke. Looking at the heat balance distribution of the coking process, the sensible heat (high-temperature waste heat) from the 950°C to 1050°C red coke ejected from the coking chamber accounts for 37% of the coke oven's total heat expenditure, the heat from the 650°C to 800°C raw coke gas (medium-temperature waste heat) accounts for 36%, the heat from the 180°C to 230°C flue gas (low-temperature waste heat) accounts for 16%, and heat loss from the furnace surface accounts for 11%.

[0003] The high-temperature waste heat brought out by red coke is generally recovered by dry quenching equipment for power generation; the medium-temperature waste heat carried by the raw gas in the coke oven riser is currently mostly cooled by spraying 70℃~75℃ circulating ammonia water to cool the medium-temperature raw gas. The raw gas is cooled to 82℃~85℃ due to the large amount of evaporation of ammonia water, and then sent to the primary cooler to be cooled to 22℃~35℃ to meet the technical requirements; for the low-temperature waste heat of the coke oven flue exhaust gas, which accounts for 16%, there is a mature technology for recycling and utilizing waste heat boilers; and for the low-temperature heat loss on the furnace surface, the only way to reduce heat loss is to strengthen insulation.

[0004] At present, the traditional process of spraying ammonia water to cool the raw gas in the riser of domestic coking plants not only loses the waste heat resources of the raw gas, but also loses the energy consumption of the cooling ammonia water heat exchange, resulting in a large amount of energy waste.

[0005] In addition, the heat dissipation of the coke oven riser causes the temperature of the furnace top platform to be high, and the working environment on the furnace top is relatively poor, threatening the physical and mental health of the workers. Summary of the Invention

[0006] The purpose of the present invention is to provide a coke oven raw gas waste heat recovery and utilization device, which has a reasonable processing flow, convenient construction, convenient maintenance, low cost, and can produce continuous and stable saturated steam.

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

[0008] The present invention provides a coke oven raw gas waste heat recovery and utilization device, comprising a raw gas system and a steam-water system. The raw gas system includes the coke oven raw gas, a riser heat exchanger, and an ammonia water spraying device. The raw gas flows through the inner cylinder of the riser heat exchanger through heat exchange and then enters the top pipe. The top pipe is connected to the ammonia water spraying device. The high-temperature and high-pressure water in the riser heat exchanger enters the steam-water system through a pipe.

[0009] The steam-water system includes a steam drum, a desalted water tank and a deaerator. The desalted water tank is connected to the deaerator through a deaerator feed water pump. The deaerator is connected to the steam drum through a steam drum feed water pump for water supply. The steam drum is connected to the riser heat exchanger through a forced circulation pump for water supply. The riser heat exchanger is connected to the steam drum through a pipeline to supply high-temperature and high-pressure water. The saturated steam generated in the steam drum is discharged through a steam pipe; the desalted water is transported to the desalted water tank through a desalted water pump; the deaerator is connected to the steam pipe of the steam drum through a pipeline.

[0010] Furthermore, the riser heat exchanger includes a heat-conducting inner tube, a coil, an outer tube, an insulation layer, an outer protective plate and a water leakage monitoring device. The heat-conducting inner tube, coil, outer tube, insulation layer and outer protective plate are arranged in sequence from the inside to the outside and connected as a whole. The water leakage monitoring device is installed at the bottom and the test end is located in the cavity between the heat-conducting inner tube and the outer tube; the bottom end of the riser heat exchanger is connected to the coke oven through a flange, and the raw gas discharged from the coke oven is transmitted to the heat-conducting inner tube through a pipeline; the bottom water inlet of the coil is connected to the main pipe for water supply through a branch pipe, and the top water outlet pipe of the coil is connected to the steam drum input pipe through a branch pipe.

[0011] Furthermore, the heat-conducting inner cylinder is specifically designed as a multi-layer structure, including a nano-heat-conducting layer, a high-temperature and corrosion-resistant alloy layer and a heat conductor layer arranged from the inside to the outside. The nano-heat-conducting layer, the high-temperature and corrosion-resistant alloy layer and the heat conductor layer are tightly attached together and welded and sealed at both ends.

[0012] Furthermore, the coil is specifically formed by bending double rows of special-shaped seamless tubes, the double rows of special-shaped seamless tubes are in close contact with the outer wall of the heat-conducting inner tube, and the curved surfaces of adjacent tubes of the double rows of special-shaped seamless tubes are in contact.

[0013] Furthermore, the outer cylinder is made of high temperature resistant and corrosion resistant material.

[0014] Furthermore, the water in the riser heat exchanger is in a bottom-in and top-out form, the bottom of the coil is connected to the water supply main pipe, and the upper outlet of the coil is connected to the return water main pipe.

[0015] Furthermore, two groups of steam drums are arranged in parallel.

[0016] A method for recovering waste heat using the coke oven raw gas waste heat recovery device as described above, comprising a raw gas heat exchange operation, a steam-water system operation, a deoxidation operation, a sewage and water drainage operation, a cooling operation, and a dosing and sampling operation;

[0017] Heat exchange operation of raw gas: the raw gas discharged from the coke oven enters the heat-conducting inner cylinder of the riser heat exchanger through a pipeline. After heat exchange, the raw gas flows into the bridge pipe. The ammonia spraying device sprays ammonia to cool the high-temperature flue gas. The flue gas is collected in the gas collecting pipe and then enters the gas primary cooler, where the circulating water and cooling water further reduce the temperature to about 21°C.

[0018] Steam-water system operation: desalted water enters the desalted water tank through the desalted water pump, and then passes through the deaerator feed water pump to the deaerator for thermal deoxygenation. The deoxygenated desalted water is sent to the steam drum through the steam drum feed water pump, flows out of the steam drum downcomer and is sent to the coil of the riser heat exchanger by the forced circulation pump. The desalted water in the coil absorbs heat from the heat-conducting inner cylinder during the upward flow and rises in temperature before entering the steam drum through the return water pipe. Steam and water separation is carried out in the steam drum, and the water is continuously sent to the riser heat exchanger for heat exchange through the forced circulation pump. The saturated steam is sent to the steam network through the steam pipe, and a portion of the saturated steam enters the deaerator for deoxygenation.

[0019] Deaeration operation: The water in the drum enters the deaerator for deaeration before being replenished. The saturated steam required by the deaerator is provided by the drum;

[0020] Dosing sampling operation: the water in the steam is treated with phosphate, and the phosphate solution is directly added to the steam drum through a metering pump. The metering pump is connected to the phosphate dosing device, and the dosing amount is manually controlled;

[0021] It also includes four sampling coolers, which are used for boiler water sampling, deoxygenated water sampling and saturated steam sampling respectively, among which boiler water sampling corresponds to two steam drums respectively.

[0022] Furthermore, it also includes sewage and drainage operations: the coke oven raw gas waste heat recovery and utilization device is provided with a periodic sewage expansion tank and a continuous sewage expansion tank, the continuous sewage pipes of the steam drum and deaerator are connected to the continuous sewage expansion tank, the steam in the continuous sewage expansion tank is connected to the deaerator, and the sewage is discharged into the dry quenching wastewater pool through a sealless automatic self-priming pump in the water accumulation pit, and is reused after unified treatment; the periodic sewage pipes of the steam drum and deaerator are connected to the periodic sewage expansion tank, and the sewage is discharged into the dry quenching wastewater pool through a sealless automatic suction pump in the water accumulation pit, and the emergency water discharge of the deaerator is connected to the buffer water tank for recycling; the emergency water discharge of the steam drum is connected to the periodic sewage expansion tank.

[0023] Furthermore, it also includes cooling operations: the circulating cooling water used by the system is taken out from the existing cooling water pipeline in the coking plant through a pipeline. The circulating cooling water is mainly used for cooling the forced circulation pump, cooling the steam drum feed pump, cooling the deaerator feed pump, cooling the desalination feed pump, and cooling the sampling device. The original circulating cooling water system of the coking plant can meet the water consumption of this system.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] 1) The coil formed by double-row special-shaped tubes has a large cross-sectional area. When the fluid with the same flow rate passes through the coil, the flow rate is small and the tube resistance is small, the air flow is smooth, and no air resistance will be generated. The selected forced circulation pump has a small head.

[0026] 2) The coil is made of special-shaped seamless tubes, and the contact surface with the heat-conducting inner tube of the riser heat exchanger is flat, with surface contact, which maximizes the heat exchange area and improves the heat exchange efficiency.

[0027] 3) The diameter of the branch pipe is large, the flow rate of the fluid in the pipe is low, the connection between the branch pipe and the main pipe is smooth, and when the fluid flows from the branch pipe to the main pipe, it does not impact the main pipe, reducing the vibration of the main pipe.

[0028] 4) To reduce management costs and safety risks for users, the coils are primarily constructed of high-temperature, high-pressure seamless alloy boiler tubes, with a pressure resistance exceeding 6 MPa and a very high safety factor. Within the riser heat exchanger, only the coils are pressurized; the rest of the structure is at atmospheric pressure and is not enclosed. According to relevant pressure vessel regulations, supervision and annual inspection are not required.

[0029] 5) The cavity formed between the heat-conducting inner tube and the outer protective plate of the riser heat exchanger is discontinuous, and the outer protective plate is a socket structure. In this way, the heat-conducting inner tube is only subjected to vertical stress during operation, but no lateral stress, avoiding the phenomenon of cracks in the bottom inner ring due to stress in two directions at the same time, and has high stability and long life.

[0030] 6) The riser heat exchanger needs to go through three layers of heat path with a total of 15mm from the inner wall of the heat-conducting inner tube to the hot water. The heat exchange is carried out by using coil water. In this way, the water in the coil is in a turbulent state with a forced high Reynolds number, and the heat transfer coefficient is significantly better than that of the laminar state.

[0031] 7) The heat-conducting inner tube of the riser heat exchanger is made of a high-temperature and corrosion-resistant alloy. The high-pressure heat exchange coil is housed in the outer cavity of the heat-conducting inner tube, which is open to the atmosphere. The water inside the coil is separated from the carbonization chamber by two layers of insulation. The cavity is open to the atmosphere, maintaining constant pressure. This stabilizes the rapidly fluctuating raw gas temperature field and keeps the heat exchange coil operating at a stable temperature of 160-200°C, preventing coil cracking. A drainage device is also provided. The pressure around the coil is constant, while the pressure inside the riser is below 150Pa. Even if a leak occurs, the water is drained out of the drain outlet to the sewer, preventing it from entering the carbonization chamber. A water leakage monitoring device is installed at the bottom of the heat exchanger. In the event of a coil leak, water is automatically discharged from the heat exchanger and the monitoring system simultaneously issues an alarm, reminding the operator to close the water inlet valve of the upper coil. If no one intervenes for an extended period, the system will intervene. This fundamentally ensures the safety of existing coke oven production and solves the problem of water leakage.

[0032] 8) The inner wall of the heat-conducting inner tube is made of imported high-temperature-resistant nano-thermal conductive material with a heat resistance of 1800°C. The tube wall is polished, leveraging the material's high corrosion resistance to maintain a consistently smooth metal surface. A reasonable heat exchange rate design ensures that the inner wall temperature does not drop below 480°C before the fire falls. This prevents tar in the raw gas from condensing, avoiding the formation of large amounts of graphite on the inner wall and clogging the bottom of the riser tube. During each coking cycle, the drastic temperature fluctuations in the riser tube heat exchanger cause the thin layer of deposited free carbon to naturally fall off and be burned away by the fire. This structure eliminates the need for manual cleaning of the riser tube heat exchanger, solving the problem of coking and clogging the riser tube.

[0033] 9) The middle high-temperature and corrosion-resistant alloy layer of the heat-conducting inner tube is made of high-heat-resistant alloy material. The structural design adopts design measures to eliminate large periodic stress field changes, so that it can work normally under periodic temperature field changes of 0-1200℃, so that it can withstand long-term dry burning and repeated water supply and discharge. In industrial tests, it dry-burned for more than 900 days without damage, which makes the riser heat exchanger have good ability to prevent "dry burning and repeated water supply and discharge".

[0034] 10) Double steam drum technology is adopted, in which one steam drum is used as a spare steam drum. When the equipment is under maintenance, or when the steam drum in use has problems and the steam drum needs annual inspection, the spare steam drum is activated; dry burning of the riser heat exchanger is avoided, and the service life of the riser heat exchanger is extended; the furnace top temperature is prevented from being too high, which affects the workers' operation; the saturated steam generated will not be interrupted and will not affect other production processes.

[0035] In summary, the process flow of the present invention is simple and reasonable, and the control is automatic; the design structure of the riser heat exchanger is simple, and the equipment size is small, which solves the problem of "fear of coking and blocking the riser", and has a good ability to prevent "fear of dry burning and repeated water supply and discharge"; the water leakage monitoring device design solves the problem of "fear of water leakage" and improves the safety of coke oven production; the double steam drum technology avoids dry burning of the riser heat exchanger, extends the service life of the riser heat exchanger, ensures that the saturated steam will not be interrupted, and does not affect other production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below with reference to the accompanying drawings.

[0037] Figure 1 This is a working diagram of the coke oven raw gas waste heat recovery and utilization device of the present invention;

[0038] Figure 2 This is a schematic structural diagram of a riser heat exchanger according to the present invention;

[0039] Figure 3 This is a working diagram of the cooling system of the present invention;

[0040] Figure 4 This is a workflow diagram of the sampling system of the present invention;

[0041] Figure 5 It is a partial schematic diagram of the raw gas system of the present invention.

[0042] Explanation of Reference Numerals: 1. Riser heat exchanger; 2. Steam drum; 3. Forced circulation pump; 4. Demineralised water pump; 5. Demineralised water tank; 6. Deaerator feed water pump; 7. Deaerator; 8. Steam drum feed water pump; 9. Saturated steam; 10. Demineralised water; 11. Raw gas; 12. Ammonia tank; 13. Continuous blowdown expansion tank; 14. Periodic blowdown expansion tank; 15. Sampling device; 1-1. Branch pipe; 1-2. Main pipe;

[0043] 101. Heat-conducting inner tube; 102. Coil; 103. Outer tube; 104. Insulation layer; 105. Outer protective plate; 106. Water leakage monitoring device. DETAILED DESCRIPTION

[0044] like Figure 1-4 As shown, a coke oven raw gas waste heat recovery and utilization device includes a raw gas system and a steam-water system. The raw gas system includes coke oven raw gas 11, a riser heat exchanger 1, and an ammonia water spraying device 12. The raw gas 11 flows through the inner tube of the riser heat exchanger 1 through heat exchange and then enters the top pipe. The top pipe is connected to the ammonia water spraying device 12, and the cooled ammonia water is returned to the chemical workshop for treatment. The high-temperature and high-pressure water in the riser heat exchanger 1 enters the steam-water system through a pipe.

[0045] The steam-water system includes a steam drum 2, a desalted water tank 5 and a deaerator 7. The desalted water tank 5 is connected to the deaerator 7 through a deaerator feed water pump 6. The deaerator 7 is connected to the steam drum 2 through a steam drum feed water pump 8 for water supply. The steam drum 2 is connected to the riser heat exchanger 1 through a forced circulation pump 3 for water supply. The riser heat exchanger 1 is connected to the steam drum 2 through a pipeline to supply high-temperature and high-pressure water. The saturated steam 9 generated in the steam drum 2 is discharged through a steam pipe; the desalted water 10 is transported to the desalted water tank 5 through a desalted water pump 4; the deaerator 7 is connected to the steam pipe of the steam drum 2 through a pipeline.

[0046] Specifically, such as Figure 2 As shown, the riser heat exchanger 1 includes a heat-conducting inner tube 101, a coil 102, an outer tube 103, an insulation layer 104, an outer protective plate 105 and a water leakage monitoring device 106. The heat-conducting inner tube 101, the coil 102, the outer tube 103, the insulation layer 104 and the outer protective plate 105 are arranged in sequence from the inside to the outside and connected as a whole. The water leakage monitoring device 106 is installed at the bottom and the test end is located in the cavity of the heat-conducting inner tube 101 and the outer tube 103; the bottom end of the riser heat exchanger 1 is connected to the coke oven through a flange, and the raw gas 11 discharged from the coke oven is transmitted to the heat-conducting inner tube 101 through a pipeline; the bottom water inlet of the coil 102 is connected to the main pipe 1-2 for water supply through a branch pipe 1-1, and the top water outlet pipe of the coil 102 is connected to the steam drum input pipe through the branch pipe 1-1. Specifically, the cavity formed between the heat-conducting inner tube and the outer protective plate is discontinuous, and the outer protective plate is a socket-and-spigot structure. This allows the heat-conducting inner tube to be subjected only to vertical stress during operation, without lateral stress. This prevents cracks in the bottom inner ring caused by simultaneous stress in two directions, resulting in high stability and long life. The design of the water leakage monitoring device 106 automatically discharges water from the heat exchanger if a coil leak occurs. The monitoring system also issues an alarm, reminding the operator to close the water inlet valve on the upper coil. If no action is taken for an extended period, the system will initiate an intervention. This fundamentally ensures the safety of existing coke oven operations and resolves the issue of water leakage.

[0047] The heat-conducting inner cylinder 101 is specifically designed as a multi-layer structure, including a nano-thermal conductive layer, a high-temperature and corrosion-resistant alloy layer, and a heat conductor layer arranged from the inside out. The nano-thermal conductive layer, the high-temperature and corrosion-resistant alloy layer, and the heat conductor layer are tightly attached together and welded and sealed at both ends. Specifically, the inner wall of the heat-conducting inner cylinder is made of imported high-temperature resistant nano-thermal conductive material with a heat resistance temperature of 1800°C. The cylinder wall is polished, and the high corrosion resistance of the material is utilized to maintain the inner wall with a smooth metal surface. A reasonable heat exchange rate design is adopted to ensure that the inner wall temperature is not lower than 480°C before the fire falls, so that the tar in the raw gas will not condense, avoiding the phenomenon of large amounts of long graphite on the inner wall and clogging the bottom of the riser. During the discharge period of each coking cycle, due to the huge change in gas temperature in the riser heat exchanger, the thin layer of deposited free carbon naturally falls off and is burned by the fire. Therefore, the riser heat exchanger with this structure does not need to be manually cleaned, solving the problem of "fear of coking and clogging the riser." The middle high-temperature and corrosion-resistant alloy layer of the heat-conducting inner tube is made of high-heat-resistant alloy material. The structural design adopts design measures to eliminate large periodic stress field changes, so that it can work normally under periodic temperature field changes of 0 to 1200℃, so that it can dry-burn for a long time and repeatedly turn the water on and off. In the industrial test, it dry-burned for more than 900 days without any damage, which makes the riser heat exchanger have a good ability to prevent "dry burning and repeated water on and off".

[0048] The coil 102 is specifically composed of a double row of special-shaped seamless pipes that are bent. The double row of special-shaped seamless pipes are in close contact with the outer wall of the heat-conducting inner tube 101, and the adjacent tubes of the double row of special-shaped seamless pipes are in curved contact. Specifically, the double row of special-shaped pipes can be rectangular, semicircular or other geometric shapes. Their cross-sectional area is large. When the fluid of the same flow rate passes through the coil, the flow rate is small, the tube resistance is small, the air flow is smooth, and no air resistance is generated. The selected forced circulation pump has a small lift. The coil is made of special-shaped seamless pipes, and the contact surface with the heat-conducting inner tube of the riser heat exchanger is flat, and the surface is in contact, so that the heat exchange area is maximized and the heat exchange efficiency is high. A drainage device is set in the riser heat exchanger 1, so that the area around the coil is in a normal pressure state and the riser is in a positive pressure state of less than 150Pa. Even if a leak occurs, the leaked water can be discharged from the drain to the sewer to avoid entering the carbonization chamber.

[0049] The outer tube 103 is constructed of high-temperature and corrosion-resistant materials. This not only isolates the entire heat exchange structure from the outside world, but also prevents any water leaks from entering the insulation layer 104 and damaging the insulation material. The insulation layer 104 adheres closely to the outer wall of the outer tube, further minimizing heat loss and lowering the operating temperature of the coke oven roof. The outer guard plate 105, surrounding the insulation layer, acts as a pressure-bearing component, protecting the riser heat exchanger from damage from the external environment.

[0050] Water in the riser heat exchanger 1 enters from the bottom and exits from the top. The bottom of the coil 102 is connected to the water supply main, and the upper outlet of the coil 102 is connected to the return main. The cavity within the coil area is filled with air. Still air has a lower thermal conductivity than insulation materials and does not generate convective heat transfer, thus effectively reducing heat loss.

[0051] The steam drum 2 is provided in two groups in parallel to form a double steam drum, one of which is used as a spare steam drum. When the equipment is under maintenance, or when a problem occurs in the steam drum in use and the steam drum needs annual inspection, the spare steam drum is activated; dry burning of the riser heat exchanger is avoided, and the service life of the riser heat exchanger is extended; the furnace top temperature is prevented from being too high, which affects the workers' operation; the generated saturated steam will not be interrupted and will not affect other production processes.

[0052] A method for recovering waste heat using the coke oven raw gas waste heat recovery device as described above, comprising a raw gas heat exchange operation, a steam-water system operation, a deoxidation operation, a sewage and water drainage operation, a cooling operation, and a dosing and sampling operation;

[0053] Raw gas heat exchange operation: The raw gas 11 discharged from the coke oven enters the heat-conducting inner cylinder 101 of the riser heat exchanger 1 through a pipeline. After heat exchange, the raw gas 11 flows into the bridge pipe. The ammonia spraying device 12 sprays ammonia to cool the high-temperature flue gas. The flue gas is collected in the gas collecting pipe and then enters the gas primary cooler, where the circulating water and cooling water further reduce the temperature to about 21°C.

[0054] Steam-water system operation: desalted water 10 enters the desalted water tank 5 through the desalted water pump 4, and then passes through the deaerator feed water pump 6 to the deaerator 7 for thermal deoxygenation. The deoxygenated desalted water 10 is sent to the steam drum 2 through the steam drum feed water pump 8, flows out of the downcomer of the steam drum 2 and is sent to the coil 102 of the riser heat exchanger 1 by the forced circulation pump 3. The desalted water in the coil 102 absorbs heat from the heat-conducting inner cylinder 101 during the upward flow and is heated up before entering the steam drum 2 through the return pipe. Steam and water separation is performed in the steam drum 2, wherein the water is further sent to the riser heat exchanger 1 through the forced circulation pump 3 for heat exchange. The saturated steam 9 is sent to the steam network through the steam pipe, and a part of the saturated steam 9 enters the deaerator 7 for deoxygenation.

[0055] Deoxygenation operation: The water in the drum 2 enters the deaerator 7 for deoxygenation before being replenished. The saturated steam required by the deaerator 7 is provided by the drum 2;

[0056] Dosing sampling operation: the water in the steam drum 2 is treated with phosphate, and the phosphate solution is directly added to the steam drum 2 through a metering pump. The metering pump is connected to the phosphate dosing device, and the dosing amount is manually controlled;

[0057] like Figure 3 、4 As shown, it also includes four sampling coolers, which are used for boiler water sampling, deoxygenated water sampling and saturated steam sampling respectively. The boiler water sampling corresponds to two steam drums respectively. The setting of the sampling cooler is mainly to monitor the water quality and steam quality to ensure that timely adjustments are made when problems are found.

[0058] It also includes sewage and drainage operations: the coke oven raw gas waste heat recovery and utilization device is provided with a regular sewage expansion tank 14 and a continuous sewage expansion tank 13, the continuous sewage pipes of the steam drum 2 and the deaerator 7 are connected to the continuous sewage expansion tank 13, the steam in the continuous sewage expansion tank 13 is connected to the deaerator 7, and the sewage is discharged into the dry quenching wastewater pool through a non-sealed automatic self-priming pump in the water accumulation pit, and is reused after unified treatment; the regular sewage pipes of the steam drum 2 and the deaerator 7 are connected to the regular sewage expansion tank 14, and the sewage is discharged into the dry quenching wastewater pool through a non-sealed automatic suction pump in the water accumulation pit, and the emergency water discharge of the deaerator 7 is connected to the buffer water tank for recycling; the emergency water discharge of the steam drum 2 is connected to the regular sewage expansion tank 14.

[0059] like Figure 3 As shown, the system also includes cooling operations: circulating cooling water is piped from the existing cooling water pipeline within the coking plant. This circulating cooling water is primarily used to cool the forced circulation pump 3, the drum feedwater pump 8, the deaerator feedwater pump 6, the desalination feedwater pump 4, and the sampling device 15. Specifically, natural water circulation is achieved through piping connections, and cooling is achieved through heat exchange. The coking plant's existing circulating cooling water system can meet the water needs of this system.

[0060] In addition, the riser heat exchanger can also use desalted water as a medium for heat exchange to directly generate steam (saturated or superheated), or it can use heat transfer oil (molten salt, etc.) as the heat exchange medium, use the heat transfer oil (molten salt) to first exchange the heat of the raw gas, and then use it directly or generate steam for application.

[0061] In general, the waste heat recovery and utilization system adopts an automatic control system when working, and normal operation does not require human intervention. The water feed pump and forced circulation pump are in hot standby state. Once a fault occurs, the system automatically detects and switches automatically; each riser heat exchanger has temperature monitoring data. Once an abnormality occurs in a riser heat exchanger, the system will automatically alarm and automatically prompt the number that needs to be processed. It is only necessary to manually close the corresponding water inlet valve, and there is no need to deal with the large system.

[0062] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A coke oven raw gas waste heat recovery and utilization device, comprising a raw gas system and a steam-water system, characterized in that: The raw gas system comprises raw gas (11), a riser heat exchanger (1) and an ammonia water spraying device (12); the raw gas (11) flows through the inner tube of the riser heat exchanger (1) and enters the top pipe after heat exchange; the top pipe is connected to the ammonia water spraying device (12); the high-temperature and high-pressure water in the riser heat exchanger (1) enters the steam-water system through a pipe; The steam-water system comprises a steam drum (2), a desalted water tank (5) and a deaerator (7); the desalted water tank (5) is connected to the deaerator (7) via a deaerator feed water pump (6); the deaerator (7) is connected to the steam drum (2) via a steam drum feed water pump (8) for water supply; the steam drum (2) is connected to the riser heat exchanger (1) via a forced circulation pump (3) for water supply; the riser heat exchanger (1) is connected to the steam drum (2) via a pipeline for high-temperature and high-pressure water supply; the saturated steam (9) generated in the steam drum (2) is discharged via a steam pipeline; the desalted water (10) is transported to the desalted water tank (5) via a desalted water pump (4); the deaerator (7) is connected to the steam pipeline of the steam drum (2) via a pipeline; The steam drums (2) are provided in two groups in parallel; The riser heat exchanger (1) comprises a heat-conducting inner tube (101), a coil (102), an outer tube (103), a thermal insulation layer (104), an outer protective plate (105), and a water leakage monitoring device (106); the heat-conducting inner tube (101), the coil (102), the outer tube (103), the thermal insulation layer (104), and the outer protective plate (105) are sequentially arranged from the inside to the outside and connected as a whole; The cavity formed between the heat-conducting inner cylinder (101) and the outer protective plate (105) is discontinuous, and the outer protective plate (105) is a socket-and-spigot structure; The heat-conducting inner cylinder (101) is specifically designed as a multi-layer structure, comprising a nano heat-conducting layer, a high-temperature and corrosion-resistant alloy layer, and a heat conductor layer arranged from the inside out, wherein the nano heat-conducting layer, the high-temperature and corrosion-resistant alloy layer, and the heat conductor layer are tightly attached together, and the two ends are welded and sealed together; The coil (102) is specifically formed by bending a double row of special-shaped seamless pipes, the double row of special-shaped seamless pipes are in close contact with the outer wall of the heat-conducting inner cylinder (101), and the curved surfaces of adjacent pipes of the double row of special-shaped seamless pipes are in contact; The inner wall temperature of the heat-conducting inner cylinder (101) is not lower than 480°C before the fire falls, so that the tar in the raw gas will not condense, and a large amount of graphite will not grow on the inner wall and block the bottom of the riser.

2. The coke oven raw gas waste heat recovery and utilization device according to claim 1 is characterized in that: The water leakage monitoring device (106) is installed at the bottom of the riser heat exchanger (1) and the test end is located in the cavity of the heat-conducting inner tube (101) and the outer tube (103); the bottom end of the riser heat exchanger (1) is connected to the coke oven through a flange, and the raw gas (11) discharged from the coke oven is transmitted to the heat-conducting inner tube (101) through a pipeline; the bottom water inlet of the coil (102) is connected to the main pipe (1-2) for water supply through a branch pipe (1-1), and the top water outlet pipe of the coil (102) is connected to the steam drum input pipe through the branch pipe (1-1).

3. The coke oven raw gas waste heat recovery and utilization device according to claim 1, characterized in that: The outer cylinder (103) is made of high temperature resistant and corrosion resistant material.

4. The coke oven raw gas waste heat recovery and utilization device according to claim 1, characterized in that: The water in the riser heat exchanger (1) enters from the bottom and exits from the top. The bottom of the coil (102) is connected to the water supply main pipe, and the upper outlet of the coil (102) is connected to the return water main pipe.

5. A method for recovering waste heat using the coke oven raw gas waste heat recovery device according to any one of claims 1 to 4, characterized in that: Including raw gas heat exchange operations, steam-water system operations, deoxidation operations, sewage and drainage operations, cooling operations, and dosing and sampling operations; Heat exchange operation of raw gas: the raw gas (11) discharged from the coke oven enters the heat-conducting inner cylinder (101) of the riser heat exchanger (1) through a pipeline. The raw gas (11) after heat exchange flows into the bridge pipe. The ammonia water spraying device (12) sprays ammonia water to cool the high-temperature flue gas. The flue gas is collected in the gas collecting pipe and then enters the gas primary cooler. The circulating water and cooling water further reduce the temperature to about 21°C. Steam-water system operation: desalted water (10) enters the desalted water tank (5) through the desalted water pump (4), and then passes through the deaerator feed water pump (6) to the deaerator (7) for thermal deoxidation. The desalted water (10) after deoxidation is sent to the steam drum (2) through the steam drum feed water pump (8), flows out from the downcomer of the steam drum (2) and is sent to the coil (102) of the riser heat exchanger (1) by the forced circulation pump (3). The desalted water in the coil (102) absorbs heat from the heat-conducting inner cylinder (101) and heats up during the upward flow, and enters the steam drum (2) through the return water pipe. Steam and water separation is performed in the steam drum (2), wherein the water is continuously sent to the riser heat exchanger (1) through the forced circulation pump (3) for heat exchange. The saturated steam (9) is sent to the steam pipe network through the steam pipe, wherein a part of the saturated steam (9) enters the deaerator (7) for deoxidation. Deoxygenation operation: the steam drum (2) enters the deaerator (7) for deoxygenation treatment before water replenishment, and the saturated steam required by the deaerator (7) is provided by the steam drum (2); Dosing sampling operation: the water in the drum (2) is treated with phosphate, and the phosphate solution is directly added to the drum (2) through a metering pump, the metering pump is connected to the phosphate dosing device, and the dosing amount is manually controlled; it also includes four sampling coolers, which are respectively used for boiler water sampling, deoxygenated water sampling and saturated steam sampling, wherein the boiler water sampling corresponds to two drums respectively.

6. The method for recovering waste heat using the coke oven raw gas waste heat recovery and utilization device according to claim 5, characterized in that: The invention also includes sewage discharge and drainage operations: the coke oven raw gas waste heat recovery and utilization device is provided with a periodic sewage expansion tank (14) and a continuous sewage expansion tank (13); the continuous sewage pipes of the drum (2) and the deaerator (7) are connected to the continuous sewage expansion tank (13); the steam in the continuous sewage expansion tank (13) is connected to the deaerator (7); the sewage is discharged into the dry quenching wastewater pool through a non-sealed automatic self-priming pump in a water accumulation pit, and is reused after unified treatment; the periodic sewage pipes of the drum (2) and the deaerator (7) are connected to the periodic sewage expansion tank (14); the sewage is discharged into the dry quenching wastewater pool through a non-sealed automatic self-priming pump in the water accumulation pit, and the emergency water discharge of the deaerator (7) is connected to the periodic sewage expansion tank (14).

7. The method for recovering waste heat using the coke oven raw gas waste heat recovery and utilization device according to claim 5, characterized in that: The system also includes cooling operations: the circulating cooling water used by the system is taken out from the existing cooling water pipeline in the coking plant through a pipeline; the circulating cooling water is mainly used for cooling the forced circulation pump (3), the drum feed water pump (8), the deaerator feed water pump (6), the desalted water pump (4), and the sampling device (15). The original circulating cooling water system of the coking plant can meet the water demand of the system.

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