Coke oven gas purification system for efficiently recycling heat source of coking plant

Abstract

The utility model discloses a coke oven gas purification system for efficiently recycling a heat source of a coking plant, which comprises a heat source recycling unit and a coke oven gas purification unit, the coke oven gas purification unit comprises a dust removal system, a desulfurization system and an ammonium sulfate elution benzene system, and the heat source recycling unit comprises a heat source recycling pipe and a boiler. The interior of a desulfurization waste liquid treatment device of the desulfurization system is sequentially divided into a stirring chamber, a crystallization chamber and a drying chamber from top to bottom through a plurality of oblique cones, the stirring chamber, the crystallization chamber and the drying chamber are communicated, a hollow shaft and a mandrel movably installed in the hollow shaft are coaxially arranged in the stirring chamber, an outer stirring plate is arranged on the upper portion of the hollow shaft through a connecting rod, and an inner stirring plate is arranged on the hollow shaft; a middle stirring plate is arranged between the outer side stirring plate and the inner side stirring plate, a cooling mechanism is arranged in the crystallization chamber, a jacket is arranged on the outer side of the drying chamber, and a steam outlet of the boiler is communicated with the jacket. In conclusion, the device has the advantages of high desulfurization waste liquid extraction efficiency, good product quality, good extraction effect and efficient recycling of a heat source.

Description

Technical Field

[0001] This utility model relates to the field of coke oven gas purification technology, specifically to a coke oven gas purification system for efficient heat source recovery in coking plants. Background Technology

[0002] The heat generated during the production process of a coking plant includes heat from the gas collecting pipe, heat from the flue gas, and heat from the wet quenching steam. The temperature of the gas collecting pipe can reach 800℃, the temperature of the flue gas can reach 200-300℃, and the temperature of the wet quenching steam can reach 400℃. This heat can be used to produce steam of different grades through heat exchange equipment.

[0003] During coking, approximately 75% of coal becomes coke, but about 25% generates various chemical products and gas, which mix and are discharged as coke oven gas. The recovery and utilization of these chemical products and gas from coke oven gas is crucial for the comprehensive utilization of coal resources. The purification process of coke oven gas is essentially the process of collecting these chemical products. This process typically includes cold-blown electrostatic precipitator stripping of ammonia, desulfurization, ammonium sulfate treatment, and benzene washing, ultimately yielding purified gas. Steam heat is used throughout the entire purification process to assist in the purification treatment at each stage. The most critical step in the coke oven gas purification process is desulfurization, which produces desulfurization wastewater containing SO4. 2- SO3 2- S2O3 2- Substances such as SCN- make desulfurization wastewater unsuitable for biochemical treatment, and direct discharge would cause significant environmental problems. Due to its high salt content, the best solution is to recover the salt from the desulfurization wastewater. This would address both the economic challenges of difficult discharge and the environmental issues caused by the wastewater, while also providing economically viable purified products. Currently, the salt recovery and extraction process for desulfurization wastewater faces challenges such as low extraction efficiency and product purity, as well as complex production processes. The remaining wastewater still contains a high salt content, failing to meet the treatment requirements for desulfurization wastewater. Therefore, developing a coke oven gas purification system for efficient heat recovery in coking plants, characterized by high extraction efficiency, good product quality, and effective extraction results, is objectively necessary. Utility Model Content

[0004] The purpose of this invention is to provide a coke oven gas purification system for efficient heat recovery in coking plants, which has high extraction efficiency, good product quality, and good extraction effect.

[0005] The purpose of this utility model is achieved as follows: it includes a heat source recovery unit and a coke oven gas purification unit. The coke oven gas purification unit includes a dust removal system, a desulfurization system, and an ammonium sulfate washing and benzene removal system. The heat source recovery unit includes a heat source recovery pipe and a boiler installed on the heat source recovery pipe. The desulfurization system includes a desulfurization tower and a desulfurization waste liquid treatment device connected to the desulfurization tower's discharge port. The interior of the desulfurization waste liquid treatment device is divided into a connected stirring chamber, a crystallization chamber, and a drying chamber from top to bottom by multiple inclined cones. A hollow shaft and a mandrel movably installed inside the stirring chamber are coaxially arranged. A drive mechanism that drives the hollow shaft and the mandrel to rotate is installed on the top of the stirring chamber. An outer stirring plate is arranged on the upper part of the hollow shaft through a connecting rod. An inner stirring plate is arranged on the hollow shaft. A middle stirring plate is arranged between the outer and inner stirring plates. The middle stirring plate is connected to the lower part of the mandrel through a connecting rod. A cooling mechanism is arranged in the crystallization chamber. A jacket is arranged on the outside of the drying chamber. The steam outlet of the boiler is connected to the jacket.

[0006] Furthermore, the cooling mechanism includes a cold water tank, an inlet pipe, and an outlet pipe. The inlet pipe and the outlet pipe are respectively located on opposite sides of the cold water tank. Several rectangular tubes are sequentially arranged at the bottom of the cold water tank along the direction from the inlet pipe to the outlet pipe. The bottom of the rectangular tubes is sealed, and a baffle plate is installed in the middle of the rectangular tube. The upper end of the baffle plate is connected to the top of the cold water tank, and a flow channel is left between the lower end and the bottom of the rectangular tube.

[0007] Furthermore, several heat-conducting plates are installed on the rectangular tube.

[0008] Furthermore, a pulverizing rod is installed at the lower end of the mandrel after it extends into the drying chamber.

[0009] Furthermore, a spiral guide plate is installed in the annular space between the jacket and the side wall of the drying chamber.

[0010] Furthermore, the hollow shaft and the mandrel rotate in opposite directions.

[0011] In operation, the heat source recovery unit utilizes the heat from the gas collecting pipes, flue gas, and wet quenching steam generated during the coking plant's production process. This heat is collected and recovered and then introduced into the boiler to generate high-temperature steam. The coke oven gas purification unit purifies the coke oven gas. It removes dust through a dust removal system, desulfurizes the gas through a desulfurization system, and further processes benzene removal through an ammonium sulfate washing and benzene removal system. During desulfurization, a desulfurization tower is used, and the resulting desulfurization wastewater is fed into a desulfurization wastewater treatment device, first entering the mixing chamber. The desulfurization waste liquid is stirred by rotating outer, middle, and inner stirring plates, ensuring thorough mixing and reducing the difficulty of subsequent crystallization and extraction. The liquid is then introduced into the crystallization chamber, where a cooling mechanism lowers its temperature, improving crystallization efficiency and preventing the sodium thiosulfate in the waste liquid from decomposing due to excessively high external temperatures. This further reduces the difficulty of crystallization. After crystallization, the crystals are sent to the drying chamber, where steam generated by the boiler is introduced into the jacket to dry the crystals using high-temperature steam. The crystals are then discharged after drying. In this invention, rotating outer, middle, and inner stirring plates are used to stir the desulfurization waste liquid. Controlling the rotational speed and direction of the hollow shaft and core shaft promotes eddy currents in the waste liquid, causing continuous collisions and fusion, thus increasing the solubility and achieving uniform stirring. This reduces the difficulty of subsequent crystallization and improves the crystallization effect. Secondly, a cooling mechanism is used to cool the desulfurization waste liquid, accelerating the crystallization speed, improving crystallization efficiency, and preventing the sodium thiosulfate in the waste liquid from decomposing due to excessively high external temperatures. This reduces the difficulty of crystallization and improves extraction efficiency. Effects: Furthermore, utilizing boiler steam for crystal drying improves product quality and ease of use. Simultaneously, the boiler's heat source comes from the heat generated during the coking process, including heat from the gas collecting pipes, flue gas, and wet quenching steam. This efficiently recovers waste heat from coking, solving the problem of wasted surplus heat in the coking plant. The heat is also reused in the coke oven gas purification system and desulfurization wastewater treatment device, addressing the difficulty in discharging desulfurization wastewater and recovering useful chemical products, thus increasing economic and environmental benefits for the enterprise. In summary, this invention boasts advantages such as high desulfurization wastewater extraction efficiency, good product quality, excellent extraction effect, and efficient heat source recovery. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0013] Figure 2 for Figure 1 A magnified structural diagram of node A in the middle;

[0014] In the diagram: 1-Heat source recovery pipe, 2-Boiler, 3-Stirring chamber, 4-Crystallization chamber, 5-Drying chamber, 6-Hollow shaft, 7-Core shaft, 8-Outer stirring plate, 9-Inner stirring plate, 10-Middle stirring plate, 11-Jacket, 12-Cold water tank, 13-Inlet pipe, 14-Outlet pipe, 15-Rectangular pipe, 16-Water baffle, 17-Heat-conducting plate, 18-Crushing rod, 19-Spiral guide plate, 20-Desulfurization waste liquid treatment device. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the present invention shall fall within the protection scope of the present invention.

[0016] like Figures 1-2 As shown, this utility model includes a heat source recovery unit and a coke oven gas purification unit. The coke oven gas purification unit includes a dust removal system, a desulfurization system, and an ammonium sulfate washing and benzene removal system. The heat source recovery unit includes a heat source recovery pipe 1 and a boiler 2 installed on the heat source recovery pipe 1. The boiler 2 is existing equipment that uses the heat source to generate steam. The desulfurization system includes a desulfurization tower and a desulfurization waste liquid treatment device 20 connected to the desulfurization tower's discharge port. The desulfurization tower is existing equipment and is not shown in this utility model. The interior of the desulfurization waste liquid treatment device 20 is divided into a connected stirring chamber 3, a crystallization chamber 4, and a drying chamber 5 from top to bottom by multiple inclined cones. A hollow shaft 6 and a mandrel 7 are coaxially arranged in the stirring chamber 3 and movably installed inside it. A drive motor is installed on the top of the stirring chamber 3 to drive the hollow shaft 6 and the mandrel 7 to rotate respectively. The structure includes a drive mechanism, which is existing technology, used to drive the hollow shaft 6 and the spindle 7 to rotate. In actual use, the spindle 7 can be driven by a separate motor, and the hollow shaft 6 can be driven by another separate motor. A corresponding gear transmission mechanism is set between the motor and the hollow shaft 6. An outer stirring plate 8 is set on the upper part of the hollow shaft 6 through a connecting rod, and an inner stirring plate 9 is set on the hollow shaft 6. A middle stirring plate 10 is set between the outer stirring plate 8 and the inner stirring plate 9. The middle stirring plate 10 is connected to the lower part of the spindle 7 through a connecting rod. A cooling mechanism is set in the crystallization chamber 4. The cooling mechanism is an existing structure used to cool the desulfurization waste liquid in the crystallization chamber 4 and promote the crystallization of the desulfurization waste liquid. A jacket 11 is set on the outside of the drying chamber 5, and the steam outlet of the boiler 2 is connected to the jacket 11.

[0017] In operation, the heat source recovery unit is used to recover heat from the gas collecting pipes, flue gas, and wet quenching steam generated during the coking plant's production process. This heat is collected and recovered and then introduced into boiler 2 to generate high-temperature steam. The coke oven gas purification unit is used for the purification of coke oven gas. Dust is removed from the coke oven gas through a dust removal system, desulfurization is performed through a desulfurization system, and subsequent benzene removal is carried out through an ammonium sulfate washing and benzene removal system. During desulfurization, a desulfurization tower is used for operation, and the resulting desulfurization waste liquid is introduced into the desulfurization waste liquid treatment device 20. It first enters the stirring chamber 3, where a rotating external... The side stirring plate 8, the middle stirring plate 10, and the inner stirring plate 9 agitate the desulfurization waste liquid, ensuring thorough mixing and stirring to reduce the difficulty of subsequent crystallization and extraction. The waste liquid is then introduced into the crystallization chamber 4, where a cooling mechanism is used to cool it down, improving the crystallization efficiency and preventing sodium thiosulfate in the waste liquid from decomposing due to excessively high external temperatures. This reduces the difficulty of crystallization. After crystallization, the waste liquid that cannot crystallize is discharged, and the crystals are sent to the drying chamber 5. Simultaneously, steam generated by the boiler 2 is introduced into the jacket 11, and the high temperature of the steam is used to dry the crystals. After drying, the crystals are discharged. In this invention, the desulfurization waste liquid is stirred by rotating outer stirring plate 8, middle stirring plate 10, and inner stirring plate 9. The rotational speed and direction of the hollow shaft 6 and core shaft 7 are controlled to induce eddies in the waste liquid, causing continuous collisions and fusion, thereby increasing the solubility and achieving uniform stirring. This reduces the difficulty of subsequent crystallization and improves the crystallization effect. Secondly, a cooling mechanism is used to cool the desulfurization waste liquid, accelerating the crystallization speed, improving crystallization efficiency, and preventing the sodium thiosulfate in the waste liquid from decomposing due to excessively high external temperatures. This reduces the difficulty of crystallization and improves the extraction efficiency. The effect is achieved; in addition, the steam generated by boiler 2 is used to dry the crystals, which improves the product quality of the crystals and makes them easier to use. On the other hand, the heat source of boiler 2 comes from the heat of the gas collecting pipe, flue gas and wet quenching steam in the coking plant production process, which efficiently recovers the waste heat of coking. This not only solves the problem of waste of surplus heat source in coking plant, but also recovers the heat for coke oven gas purification system and desulfurization waste liquid treatment device 20, solving the problem of difficult discharge of desulfurization waste liquid, and recovering useful chemical products, which increases the economic and environmental benefits of the enterprise.

[0018] The cooling mechanism includes a cold water tank 12, an inlet pipe 13, and an outlet pipe 14. The inlet pipe 13 and the outlet pipe 14 are respectively arranged on opposite sides of the cold water tank 12. Several rectangular tubes 15 are arranged sequentially along the bottom of the cold water tank 12 from the inlet pipe 13 to the outlet pipe 14. The bottom of the rectangular tubes 15 is sealed. A baffle plate 16 is arranged in the middle of the rectangular tubes 15. The upper end of the baffle plate 16 is connected to the top of the cold water tank 12, and a flow channel is left between the lower end and the bottom of the rectangular tubes 15. During operation, cold water enters the cold water tank 12 from the inlet pipe 13. It is blocked by the baffle plate 16 and flows downward along the first rectangular pipe 15. When it reaches the bottom of the rectangular pipe 15, it flows back upward into the cold water tank 12. Then it flows downward along the second rectangular pipe 15. After reaching the bottom of the rectangular pipe 15, it flows back upward into the cold water tank 12, and so on. The cold water flows in the cold water tank 12 and several rectangular pipes 15. During the flow, it absorbs heat from the desulfurization waste liquid, reduces the temperature of the desulfurization waste liquid, and achieves the purpose of cooling the desulfurization waste liquid.

[0019] A number of heat-conducting plates 17 are provided on the rectangular tube 15. The heat-conducting plates 17 have good heat conduction efficiency, which can increase the heat exchange area of ​​cold water and desulfurization waste liquid, and improve the heat exchange efficiency of cold water and desulfurization waste liquid, thereby ensuring the crystallization efficiency of desulfurization waste liquid.

[0020] After the lower end of the mandrel 7 extends into the drying chamber 5, a stirring rod 18 is provided. The stirring rod 18 is set on the mandrel 7 and rotates together with the mandrel 7. It can stir the crystals in the drying chamber 5, breaking them up on the one hand and turning them over on the other, thereby improving the drying efficiency and effect of the crystals and preventing them from clumping.

[0021] A spiral guide plate 19 is provided in the annular space between the jacket 11 and the side wall of the drying chamber 5. In this invention, steam is introduced into the jacket 11 to dry the crystals in the drying chamber 5. However, in actual use, the uneven distribution of steam in the jacket 11 leads to uneven drying of the crystals. To solve this problem, the spiral guide plate 19 is provided so that the steam flows along the spiral channel formed by the spiral guide plate 19, eliminating dead zones in the steam flow, improving the uniformity of steam distribution, and thus improving the problem of uneven drying of the crystals.

[0022] The hollow shaft 6 and the core shaft 7 rotate in opposite directions. The outer stirring plate 8 and the inner stirring plate 9 are fixed to the hollow shaft 6. As the hollow shaft 6 rotates synchronously, the middle stirring plate 10 is fixed to the core shaft 7. As the core shaft 7 rotates synchronously, the outer stirring plate 8 and the inner stirring plate 9 drive the desulfurization waste liquid on the outside and inside of the stirring chamber 3 to rotate and form vortices. The middle stirring plate 10 drives the desulfurization waste liquid between the outer stirring plate 8 and the inner stirring plate 9 to rotate. When the hollow shaft 6 and the core shaft 7 rotate in opposite directions, the vortices formed by the three desulfurization waste liquids collide and merge with each other, thereby making the desulfurization waste liquid more fully mixed and stirred, improving the stirring and mixing efficiency, and reducing the difficulty of crystal extraction.

Claims

1. A coking plant heat source efficient recycling coke oven gas purification system comprising a heat source recycling unit and a coke oven gas purification unit, the coke oven gas purification unit comprising a dust removal system, a desulfurization system and an ammonium sulfate benzene washing and desorption system, characterized in that The heat source recycling unit comprises a heat source recycling pipe (1) and a boiler (2) arranged on the heat source recycling pipe (1), the desulfurization system comprises a desulfurization tower and a desulfurization waste liquid treatment device (20) communicated with a liquid outlet of the desulfurization tower, the inside of the desulfurization waste liquid treatment device (20) is sequentially separated into a stirring chamber (3), a crystallization chamber (4) and a drying chamber (5) communicated from top to bottom through a plurality of inclined cones, a hollow shaft (6) and a movable core shaft (7) movably arranged in the hollow shaft (6) are coaxially arranged in the stirring chamber (3), a driving mechanism for driving the hollow shaft (6) and the core shaft (7) to rotate is arranged on the top of the stirring chamber (3), an outer stirring plate (8) is arranged on the upper part of the hollow shaft (6) through a connecting rod, an inner stirring plate (9) is arranged on the hollow shaft (6), a middle stirring plate (10) is arranged between the outer stirring plate (8) and the inner stirring plate (9), the middle stirring plate (10) is connected with the lower part of the core shaft (7) through a connecting rod, a cooling mechanism is arranged in the crystallization chamber (4), a jacket (11) is arranged outside the drying chamber (5), and the steam outlet of the boiler (2) is communicated with the jacket (11).

2. The coke oven gas cleaning system for efficient recovery of heat sources in a coking plant according to claim 1, characterized in that: The cooling mechanism comprises a cold water tank (12), a water inlet pipe (13) and a water outlet pipe (14), the water inlet pipe (13) and the water outlet pipe (14) are arranged on opposite sides of the cold water tank (12) respectively, a plurality of rectangular pipes (15) are sequentially arranged on the bottom of the cold water tank (12) in the direction from the water inlet pipe (13) to the water outlet pipe (14), the bottom of the rectangular pipe (15) is blocked, a waterproof plate (16) is arranged in the middle of the rectangular pipe (15), the upper end of the waterproof plate (16) is connected with the top of the cold water tank (12), and a flow channel is left between the lower end of the waterproof plate (16) and the bottom of the rectangular pipe (15).

3. The coke oven gas cleaning system for efficient recovery of heat sources in a coking plant according to claim 2, characterized in that: A plurality of heat-conducting plates (17) are arranged on the rectangular pipe (15).

4. The coke oven gas cleaning system for efficient recovery of heat sources in a coking plant according to claim 1, characterized in that: After the lower end of the core shaft (7) extends into the drying chamber (5), a stirring and crushing rod (18) is arranged.

5. The coke oven gas cleaning system for efficient recovery of heat sources in a coking plant as claimed in claim 1 wherein: A spiral guide plate (19) is arranged in the annular space between the jacket (11) and the side wall of the drying chamber (5).

6. The coke oven gas cleaning system for efficient recovery of heat sources in a coking plant as claimed in claim 1 wherein: The rotation directions of the hollow shaft (6) and the core shaft (7) are opposite.

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