Coke oven gas primary cooling device

Abstract

The invention belongs to the technical field of coke oven gas primary cooling, and particularly relates to a coke oven gas primary cooling device which comprises a high-temperature dust remover, a coal gas heat exchanger, an electrical tar precipitator and a desulfurizing tower, a gas inlet of the high-temperature dust remover is communicated with a coal gas outlet of a coke oven, and a gas outlet of the high-temperature dust remover is communicated with a gas inlet of the coal gas heat exchanger; a gas outlet of the gas heat exchanger is communicated with a gas inlet of the electrical tar precipitator, a gas outlet of the electrical tar precipitator is communicated with a gas inlet of the desulfurizing tower, and a gas outlet of the desulfurizing tower is communicated with a fuel gas inlet of the coke oven. The device has the beneficial effects that the use of ammonia with strong corrosivity is avoided, the wet gas generated by the coke oven is used as a circulating heat-carrying medium, the recycling of coke oven gas heat is realized, the online cleaning of the tube pass of the gas heat exchanger is realized by improving the gas heat exchanger, and the service life of the gas heat exchanger is prolonged. The problem of tar blockage in the coal gas cooling process is solved, and the process is cleaner and more efficient compared with a traditional process.

Description

Technical Field

[0001] The invention belongs to the technical field of primary cooling of coke oven gas, and in particular relates to a primary cooling device for coke oven gas. Background Art

[0002] The primary cooling of coal gas refers to the process of spraying ammonia water through the gas collecting pipe and setting up a primary cooler to reduce the temperature of the outgoing coal from 650℃-800℃ to about 25℃. Traditional cooling methods require spraying ammonia water to initially remove dust, sulfur, naphthalene and other impurities in the coal gas. However, due to the high temperature of the flue gas out of the furnace, a large amount of ammonia water needs to be sprayed. A large amount of ammonia vapor will be generated during the spraying process, causing environmental pollution, equipment corrosion and other problems. In addition, product purification and ammonia loss in the subsequent process will cause additional production costs. Summary of the invention

[0003] The present application provides a coke oven gas primary cooling device, aiming to solve the problems of the prior art that the gas cooling process is complex, the cost is high, and the cooling process causes equipment corrosion and environmental pollution.

[0004] The present application provides a coke oven gas primary cooling device, comprising a high-temperature dust collector, a gas heat exchanger, an electric tar precipitator and a desulfurization tower, wherein the air inlet of the high-temperature dust collector is connected to the gas outlet of the coke oven, the air outlet of the high-temperature dust collector is connected to the air inlet of the gas heat exchanger, the air outlet of the gas heat exchanger is connected to the air inlet of the electric tar precipitator, the air outlet of the electric tar precipitator is connected to the air inlet of the desulfurization tower, and the air outlet of the desulfurization tower is connected to the fuel air inlet of the coke oven.

[0005] The device described in the present application avoids the use of highly corrosive ammonia that pollutes the environment, and adopts the wet coal gas (mixed gas of water vapor and coal gas) produced by the coke oven as the circulating heat carrier medium, thereby realizing the recycling of the heat of the coke oven gas. By improving the coal gas heat exchanger, online cleaning of the coal gas heat exchanger tube is realized, and the problem of tar blockage during the coal gas cooling process is solved, making this process cleaner and more efficient than the traditional process.

[0006] According to some embodiments of the coke oven gas primary cooling device described in the present application, it also includes a gas circulation pipe, one end of which is connected to the gas outlet of the high-temperature dust collector through a two-way valve, and the other end of the gas circulation pipe is connected to the calcined product outlet of the coke oven.

[0007] According to some embodiments of the coke oven gas primary cooling device described in the present application, a flow control valve is provided on the gas circulation pipe.

[0008] According to some embodiments of the coke oven gas primary cooling device described in the present application, the flow rate of the coal gas circulating through the coal gas circulation pipe is 1 / 4-1 / 5 of the total amount of the coal gas treated by the high-temperature dust collector.

[0009] According to some embodiments of the coke oven gas primary cooling device of the present application, the gas heat exchanger includes a main pipe and a sleeve heat exchange cylinder connected to the main pipe, one end of the main pipe is connected to the gas outlet of the high-temperature dust collector, and the other end of the main pipe is a closed end;

[0010] One end of the tube-in-tube heat exchange tube is connected to the main pipe, and the other end of the tube-in-tube heat exchange tube is connected to the air inlet of the electric tar precipitator.

[0011] According to some embodiments of the coke oven gas primary cooling device described in the present application, it also includes a tar separation tank, the other end of the shell and tube heat exchange tube is connected to the inlet of the tar separation tank, and the air outlet of the tar separation tank is connected to the air inlet of the electric tar precipitator.

[0012] According to some embodiments of the coke oven gas primary cooling device of the present application, the shell and tube heat exchange tube is vertically arranged to the main pipe, and the shell and tube heat exchange tube is vertically arranged.

[0013] According to some embodiments of the coke oven gas primary cooling device described in the present application, the number of the shell and tube heat exchanger tubes is several, the tube sides of the several shell and tube heat exchanger tubes are arranged in parallel, the shell sides of the several shell and tube heat exchanger tubes are arranged in parallel, the shell sides of the shell and tube heat exchanger tubes are provided with cooling water inlets and outlets, and the cooling water inlet is provided with an inlet valve.

[0014] According to some embodiments of the coke oven gas primary cooling device described in the present application, the number of the shell and tube heat exchange tubes is 6.

[0015] According to some embodiments of the coke oven gas primary cooling device described in the present application, a coke discharge port and a water discharge port are provided at the bottom of the tar separation tank, and a manhole is also provided on the tar separation tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the coke oven gas primary cooling device described in this application;

[0017] Figure 2 This is a schematic diagram of the structure of the gas heat exchanger described in this application;

[0018] In the figure: 1. high-temperature dust collector, 2. coal gas heat exchanger; 3. electric tar precipitator; 4. desulfurization tower; 5. tar separation tank, 6. two-way valve; 21. shell and tube heat exchanger, 22. drain valve, 23. water inlet valve; 24. coke discharge port; 25. drain port, 26. manhole, 27. main pipe, 28 the gas outlet of the tar separation tank. DETAILED DESCRIPTION

[0019] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0020] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0021] An embodiment of the present application provides a coke oven gas primary cooling device, comprising a high-temperature dust collector, a gas heat exchanger, an electric tar precipitator and a desulfurization tower, wherein the air inlet of the high-temperature dust collector is connected to the gas outlet of the coke oven, the air outlet of the high-temperature dust collector is connected to the air inlet of the gas heat exchanger, the air outlet of the gas heat exchanger is connected to the air inlet of the electric tar precipitator, the air outlet of the electric tar precipitator is connected to the air inlet of the desulfurization tower, and the air outlet of the desulfurization tower is connected to the fuel air inlet of the coke oven.

[0022] The temperature of the coal gas flowing out of the coal gas outlet of the coke oven is generally around 600-800℃. After passing through the high-temperature dust collector, most of the solid impurities are filtered out. The coal gas filtered by the high-temperature dust collector is then indirectly cooled through the coal gas heat exchanger from top to bottom. The temperature of the coal gas cooled by the coal gas heat exchanger is controlled at 50-55℃ to reduce the condensation of naphthalene and cause equipment blockage. In this process, most of the water vapor in the coal gas is condensed and separated from the coal gas. The coal gas treated by the coal gas heat exchanger enters the electric tar collector to further remove tar, and then enters the desulfurization tower to directly cool the coal gas to 35℃, remove gases such as hydrogen sulfide and hydrogen cyanide, and obtain dry and clean coal gas, which enters the fuel system of the coke oven for combustion to provide energy for the coke oven.

[0023] The device described in the present application avoids the use of highly corrosive ammonia that pollutes the environment, and adopts the wet coal gas (mixed gas of water vapor and coal gas) produced by the coke oven as the circulating heat carrier medium, thereby realizing the recycling of the heat of the coke oven gas. By improving the coal gas heat exchanger, online cleaning of the coal gas heat exchanger tube is realized, and the problem of tar blockage during the coal gas cooling process is solved, making this process cleaner and more efficient than the traditional process.

[0024] In some embodiments of the present application, the coke oven gas primary cooling device further includes a gas circulation pipe, one end of which is connected to the gas outlet of the high-temperature dust collector through a two-way valve, and the other end of which is connected to the outlet of the calcined product of the coke oven. The provision of the gas circulation pipe can reduce the processing load of the coke oven gas primary cooling device, and the gas flowing out through the gas circulation pipe is connected to the outlet of the calcined product of the coke oven, that is, the gas flowing out through the gas circulation pipe contacts and exchanges heat with the fly ash produced by the coke oven, so that the outlet temperature of the fly ash is reduced to below 300°C, and the circulating gas is heated, and the heated gas contacts the material added to the coke oven, preheats the material to raise the temperature of the material, and generates new gas. The heat of the coke oven is saved, and the production cost is reduced.

[0025] In some embodiments of the present application, a flow control valve is provided on the gas circulation pipe.

[0026] In some embodiments of the present application, the flow rate of the coal gas circulating through the coal gas circulation pipe is 1 / 4-1 / 5 of the total amount of coal gas treated by the high-temperature dust collector.

[0027] In some embodiments of the present application, the coal gas heat exchanger includes a main pipe and a sleeve heat exchanger connected to the main pipe, one end of the main pipe is connected to the gas outlet of the high-temperature dust collector, and the other end of the main pipe is a closed end;

[0028] The sleeve heat exchanger includes a tube side and a shell side sleeved on the outside of the tube side. One end of the sleeve heat exchanger tube side is connected to the main pipe, and the other end of the sleeve heat exchanger tube side is connected to the air inlet of the electric tar precipitator. The coal gas filtered by the high-temperature dust collector enters the sleeve heat exchanger from top to bottom for cooling. The wet coal gas goes through the tube side and the cooling water goes through the shell side. During the cooling process, most of the water vapor and coal tar are condensed and removed, separated from the coal gas, and flow down along the tube wall of the heat exchanger, while the cooled coal gas enters the electric tar precipitator for the next operation.

[0029] During the cooling process of the shell-and-tube heat exchanger, the temperature of the coal gas at its outlet is controlled at 50-55°C to prevent naphthalene condensation from causing equipment blockage. In this process, the water vapor generated by the heat exchange of the cooling water returns to the cooling water circulation system, replacing the step of spraying ammonia water in the traditional process, reducing the application of ammonia water, avoiding the problems of equipment corrosion and environmental pollution caused by the use of ammonia water, making the coal gas cooling operation more environmentally friendly and lower in cost.

[0030] In some embodiments of the present application, a tar separation tank is further included, the other end of the shell and tube heat exchange tube is connected to the inlet of the tar separation tank, and the air outlet of the tar separation tank is connected to the air inlet of the electric tar precipitator.

[0031] The water and coal tar separated by cooling of the shell and tube heat exchanger flow into the tar separation tank along the inner wall of the shell and tube heat exchanger tube. In the tar separation tank, the tar and water are separated into layers due to different densities and then discharged from different discharge ports.

[0032] In some embodiments of the present application, the shell and tube heat exchange tube is perpendicularly arranged to the main pipe, and the shell and tube heat exchange tube is vertically arranged.

[0033] In some embodiments of the present application, the number of the shell heat exchange tubes is several, the tube sides of several of the shell heat exchange tubes are arranged in parallel, the shell sides of several of the shell heat exchange tubes are arranged in parallel, the shell sides of the shell heat exchange tubes are all provided with cooling water inlet and outlet, and the cooling water inlet is provided with a water inlet valve. The shell sides of multiple shell heat exchange tubes are used in parallel, so that during the gas cooling process, the cooling water inlet valve of one of the shell heat exchange tubes can be closed, that is, the cooling of the wet gas entering the shell heat exchange tube can be stopped, and the high temperature characteristics of the wet gas can be used to heat the tar adhered to the inner wall of the shell heat exchange tube, so that the tar is gasified and then separated from the inner wall of the shell heat exchange tube, so as to achieve self-cleaning of the shell heat exchange tube, avoid the problem of blockage due to the adhesion of tar, and further reduce the production cost.

[0034] In some embodiments of the present application, the number of the shell and tube heat exchange tubes is 6.

[0035] In some embodiments of the present application, the bottom of the tar separation tank is provided with a coke discharge port and a water discharge port, and the tar separation tank is also provided with a manhole. The provision of the manhole facilitates the cleaning of the tar separation tank.

[0036] The technical solution of the present application is described in detail below in conjunction with specific embodiments and drawings. Specific embodiments

[0038] A coke oven gas primary cooling device comprises a high-temperature dust collector 1, a gas heat exchanger 2, an electric tar collector 3, a desulfurization tower 4 and a gas circulation pipe, wherein the air inlet of the high-temperature dust collector 1 is connected to the gas outlet of the coke oven, the air outlet of the high-temperature dust collector 1 is connected to the air inlet of the gas heat exchanger 2, the air outlet of the gas heat exchanger 2 is connected to the air inlet of the electric tar collector 3, the air outlet of the electric tar collector 3 is connected to the air inlet of the desulfurization tower 4, and the air outlet of the desulfurization tower 4 is connected to the fuel air inlet of the coke oven;

[0039] One end of the gas circulation pipe is connected to the gas outlet of the high-temperature dust collector 1 through a two-way valve 6, and the other end of the gas circulation pipe is connected to the calcined product outlet of the coke oven, which is used to cool the calcined products of the coke oven and preheat the raw materials added to the coke oven. In order to facilitate the control of the circulation flow of the gas, a flow control valve is provided on the gas circulation pipe to control the amount of circulating gas to 1 / 5 of the total amount of gas processed by the high-temperature dust collector 1.

[0040] In order to avoid problems such as pipeline blockage and equipment corrosion caused by direct cooling of coal gas, the gas heat exchanger 2 used in the present application includes a main pipe 27 and a shell and tube heat exchanger tube 21 connected to the main pipe 27, one end of the main pipe 27 is connected to the air outlet of the high-temperature dust collector 1, and the other end of the main pipe 27 is a closed end; the shell and tube heat exchanger tube 21 includes a tube side and a shell side sleeved on the outside of the tube side, one end of the tube side is connected to the main pipe 27, and the other end of the tube side is connected to the air inlet of the electric tar precipitator 3.

[0041] In order to facilitate the separation of water, coal tar and coal gas generated during the condensation process of the coal gas heat exchanger 2, the sleeve heat exchange cylinder 21 is vertically arranged with the main pipe 27, and the sleeve heat exchange cylinder 21 is arranged vertically. In order to facilitate the storage of water and coal tar generated by condensation, the device is also provided with a tar separation tank 5, the other end of the sleeve heat exchange cylinder 21 is connected to the inlet of the tar separation tank 5, and the air outlet 28 of the tar separation tank 5 is connected to the air inlet of the electric tar collector 3. A coke discharge port 24 and a water outlet 25 are provided at the bottom of the tar separation tank 5. In order to facilitate the cleaning of the tar separation tank 5, a manhole 26 is provided on the tar separation tank 5.

[0042] In the embodiment of the present application, the number of the shell and tube heat exchange tubes 21 is 6, the tube sides of the 6 shell and tube heat exchange tubes 21 are arranged in parallel, and the shell sides of several shell and tube heat exchange tubes 21 are arranged in parallel. The shell side of the shell and tube heat exchange tube 21 is provided with a cooling water inlet and outlet, and a water inlet valve 23 is provided at the cooling water inlet, so as to control the cooling water inlet and outlet of a single shell and tube heat exchange tube 21.

[0043] Method for using the coke oven gas primary cooling device described in Example 1 of the present application:

[0044] During the production process, the gas outlet of the coke oven is connected to the high-temperature dust collector 1. After the wet gas flowing out of the coke oven is processed by the high-temperature dust collector 1, under the action of the two-way valve 6, part of the gas flows into the gas heat exchanger 2, and the other part flows into the fuel air inlet of the coke oven through the gas circulation pipe.

[0045] In this embodiment, the temperature of the coal gas after being treated by the high-temperature dust collector 1 is about 250°C. The wet coal gas flowing into the fuel air inlet of the coke oven through the coal gas circulation pipe contacts the fly ash (the temperature of the fly ash is about 800°C) produced by the calcination of the coke oven, so that the temperature of the fly ash is reduced to below 300°C, and the circulating coal gas is heated. The circulating coal gas carrying heat contacts the materials added to the coke oven, raising the temperature of the materials and saving energy. The materials generate new wet coal gas during the calcination process, and the wet coal gas enters the high-temperature dust collector 1 for treatment. In order to ensure that the ratio of coal gas and water vapor in the coal gas produced by the coke oven is 1:3, the amount of circulating coal gas is controlled to be 1 / 5 of the total amount of coal gas treated by the high-temperature dust collector 1 to maintain the balance of the ratio of coal gas and water vapor, otherwise it will cause problems such as insufficient heat carrying capacity and tar accumulation in the pipeline.

[0046] The wet gas flowing into the gas heat exchanger 2 simultaneously enters six parallel-connected shell-and-tube heat exchange cylinders 21. Cooling water flows through the shell side of the shell-and-tube heat exchange cylinders 21. After the wet gas is processed by the gas heat exchanger 2, water and tar are condensed and separated from the gas, flow down along the tube wall of the gas heat exchanger 2, and fall into the tar separation tank 5. The gas flows out from the gas outlet of the tar separation tank 5 and enters the electric tar collector 3. In order to facilitate the discharge of tar and condensed water in the tar separation tank 5, the bottom of the tar separation tank 5 has a certain inclination angle to facilitate the outflow of liquid. In order to prevent tar from adhering to the inner wall of the tar separation tank 5, a steam coil can be installed on the tar separation tank 5. When cleaning the tar, the bottom of the tar separation tank 5 is heated to facilitate the outflow of tar. The water and tar flowing into the tar separation tank 5 will be stratified. The tar discharge port 24 and the water discharge port 25 of the tar separation tank 5 can be used to discharge the tar and water accumulated in the tar separation tank 5 respectively. A manhole 26 is provided on the tar separation tank 5 to facilitate the cleaning of the tar separation tank 5.

[0047] To prevent tar from adhering to the inner wall of the tube of the gas heat exchanger 2 and causing blockage. During operation, high-temperature wet gas can be used to flush the six sleeve heat exchange cylinders 21 one by one. The specific operation is: after the coke oven gas primary cooling device has been running for 30 minutes, close the water inlet valve 23 of the first sleeve heat exchange cylinder 21 (the first of the six sleeve heat exchangers from left to right), and open its drainage valve 22. At this time, the wet gas entering the tube of the sleeve heat exchange cylinder 21 is not cooled, and the temperature of the wet gas is as high as about 250°C. Under the flushing effect of the high-temperature wet gas, the tar adhering to the inner wall of the tube is gasified again, realizing the self-cleaning of the sleeve heat exchange cylinder 21 and avoiding blockage caused by the adhesion of tar. After the high-temperature wet gas runs in the first sleeve heat exchange cylinder 21 for 5 minutes without cooling, the tar adhering to the sleeve heat exchanger is basically flushed clean, and then the cooling water inlet valve 23 is reopened for normal cooling. Then close the cooling water inlet valve 23 of the second sleeve heat exchanger tube 21, and repeat the above operation until all six sleeve heat exchanger tubes 21 are self-cleaned, so as to realize continuous operation of primary cooling of coke oven gas without clogging.

[0048] During the self-cleaning process of the shell and tube heat exchanger tube 21, the tar is gasified under the action of high temperature, and the tar mist cannot be condensed, resulting in incomplete tar separation, which will increase the load of the electric tar collector 3. Therefore, multiple shell and tube heat exchanger tubes 21 are connected in parallel as much as possible. If the subsequent process has high requirements on product quality, a control valve and a cleaning pipeline can be installed at the gas inlet of the shell and tube heat exchanger tube 21. The high-temperature clean gas enters from the bottom and returns to the shell and tube heat exchanger inlet from the top after cleaning.

[0049] The coal gas flowing out of the tar separation tank 5 enters the electric tar collector 3 to further remove tar, and then enters the desulfurization tower 4 for direct cooling. The desulfurizer is sprayed out from the top of the desulfurization tower 4, and the coal gas rises from the bottom of the desulfurization tower 4. The countercurrent contact heat exchange desulfurization is carried out, and the coal gas is cooled to 35°C. The removed sulfur element and naphthalene crystals enter the sedimentation tank for separation, and the circulating liquid is pumped to the top of the desulfurization tower 4 again. The clean and dry coal gas obtained enters the fuel system of the coke oven and is burned to provide energy for the coke oven.

[0050] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A coke oven gas primary cooling device, characterized in that: It includes a high-temperature dust collector, a gas heat exchanger, an electric tar precipitator and a desulfurization tower. The air inlet of the high-temperature dust collector is connected to the gas outlet of the coke oven, the air outlet of the high-temperature dust collector is connected to the air inlet of the gas heat exchanger, the air outlet of the gas heat exchanger is connected to the air inlet of the electric tar precipitator, the air outlet of the electric tar precipitator is connected to the air inlet of the desulfurization tower, and the air outlet of the desulfurization tower is connected to the fuel air inlet of the coke oven.

2. The coke oven gas primary cooling device according to claim 1, characterized in that: It also includes a gas circulation pipe, one end of which is connected to the gas outlet of the high-temperature dust collector through a two-way valve, and the other end of the gas circulation pipe is connected to the calcined product outlet of the coke oven.

3. The coke oven gas primary cooling device according to claim 2, characterized in that: The gas circulation pipe is provided with a flow control valve.

4. The coke oven gas primary cooling device according to claim 2, characterized in that: The flow rate of the coal gas circulating through the coal gas circulation pipe is 1 / 4-1 / 5 of the total amount of the coal gas treated by the high-temperature dust collector.

5. The coke oven gas primary cooling device according to claim 1, characterized in that: The coal gas heat exchanger comprises a main pipe and a sleeve heat exchange cylinder connected to the main pipe, one end of the main pipe is connected to the gas outlet of the high-temperature dust collector, and the other end of the main pipe is a closed end; The shell-and-tube heat exchange tube comprises a tube side and a shell side sleeved on the outside of the tube side. One end of the tube side is connected to the main pipe, and the other end of the tube side is connected to the air inlet of the electric tar collector.

6. The coke oven gas primary cooling device according to claim 5, characterized in that: It also includes a tar separation tank, the other end of the shell and tube heat exchange tube is connected to the inlet of the tar separation tank, and the air outlet of the tar separation tank is connected to the air inlet of the electric tar collector.

7. The coke oven gas primary cooling device according to claim 5, characterized in that: The sleeve heat exchange tube is vertically arranged with respect to the main pipe, and the sleeve heat exchange tube is vertically arranged.

8. The coke oven gas primary cooling device according to claim 5 or 6, characterized in that: There are several shell-and-tube heat exchange tubes, the tube sides of several shell-and-tube heat exchange tubes are arranged in parallel, the shell sides of several shell-and-tube heat exchange tubes are arranged in parallel, the shell sides of the shell-and-tube heat exchange tubes are all provided with cooling water inlets and outlets, and the cooling water inlets are provided with water inlet valves.

9. The coke oven gas primary cooling device according to claim 5 or 6, characterized in that: The number of the shell and tube heat exchange tubes is 6.

10. The coke oven gas primary cooling device according to claim 6, characterized in that: The bottom of the tar separation tank is provided with a tar discharge port and a water discharge port, and the tar separation tank is also provided with a manhole.

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