A combined treatment device and method for cooling and purifying coal gas

Abstract

The present invention relates to the cooling of coke oven gas in coking production and the purification of coal powder in the gas, and in particular to a combined treatment device and method for cooling and purifying coal gas. From top to bottom, there are a first coal powder purification stage, a primary cooling stage and a second coal powder purification stage, and also include a flushing circulation pump and a tail liquid circulation pump; the first coal powder purification stage is provided with a first flushing pipe, a distribution plate, a cyclone separation device, a second flushing pipe and a liquid cut-off plate from top to bottom, a raw gas inlet is provided on the top of the body, and a first outlet and a second outlet are provided on the bottom side wall; the primary cooling stage is divided into three parts from top to bottom: a heating water section, a circulating water section and a low-temperature water section, and is provided with a third flushing pipe; the second coal powder purification stage is provided with a circulating ammonia water spraying device and a cyclone separation device from top to bottom, and a coal gas outlet and a third outlet are provided on the bottom side wall of the second coal powder purification stage body. While removing coal powder from the coal gas, the heat of the coal gas is not wasted, the calorific value of the coal gas is fully utilized, and there is no external discharge of liquid in the entire process, which is energy-saving and environmentally friendly.

Description

Technical Field

[0001] The invention relates to the cooling of coke oven gas in coking production and the purification of coal powder in the gas, and in particular to a combined treatment device and method for cooling and purifying the gas. Background Art

[0002] The primary cooler is the main equipment in the coke oven gas cooling process. With the increasing production capacity of coke ovens, the amount of coal powder entrained in the raw gas has increased dramatically, blocking the interior of the primary cooler equipment, resulting in a significant decrease in cooling efficiency, frequent maintenance, increased energy consumption and operating costs, and increased difficulty in subsequent gas purification. If a direct cooling tower is set up in front of the primary cooler and the gas is directly sprayed with circulating ammonia water, a large amount of coal powder can be removed, but a large amount of heat in the gas is wasted, and the cooling of the circulating ammonia water also consumes a large amount of low-temperature water. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the present invention provides a combined treatment device and method for coal gas cooling and purification. While removing coal powder from coal gas, the heat of coal gas is not wasted, the calorific value of coal gas is fully utilized, and there is no external liquid in the whole process, which is energy-saving and environmentally friendly, laying a good foundation for subsequent coal gas purification treatment.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A coal gas cooling and purification combined treatment device, the device is divided into three sections, namely, a coal powder purification section, a primary cooling section and a coal powder purification section two from top to bottom, and also includes a flushing circulation pump and a tail liquid circulation pump; the coal powder purification section one is provided with a first flushing pipe, a distribution plate, a cyclone separation device, a second flushing pipe and a liquid cut-off plate from top to bottom, a raw gas inlet is provided on the top of the main body, and a first outlet and a second outlet are provided on the bottom side wall; the primary cooling section is divided into a heating water section, a circulating water section and a low-temperature water section from top to bottom, and the primary cooling section is provided with a third flushing pipe; the coal powder purification section two is provided with a circulating ammonia water spraying device and a cyclone separation device from top to bottom, and the coal powder purification section two The bottom side wall of the main body is provided with a coal gas outlet and a third outlet.

[0006] The first outlet and the second outlet are connected to the tail liquid circulation pump through pipelines respectively, the third outlet is connected to the tail liquid circulation pump through a pipeline, and the tail liquid circulation pump is connected to the raw gas pipeline through a pipeline.

[0007] The first flushing pipe, the second flushing pipe and the third flushing pipe are respectively connected to the flushing circulation pump through pipelines, and the third outlet is connected to the flushing circulation pump through a pipeline.

[0008] A combined treatment method for coal gas cooling and purification comprises the following steps:

[0009] 1) Raw coal gas enters the coal powder purification section from the raw coal gas inlet, and enters the cyclone separation device after passing through the distribution plate. The airflow carrying a large amount of coal powder is swirled out. Under the centrifugal force generated by the gas rotation and the gravity of the coal particles themselves, most of the coal particles are thrown to the inner wall of the coal powder purification section and adsorbed on the inner wall surface;

[0010] 2) The rotating jetted airflow collides with the liquid cut-off plate when flowing downward, and some coal particles are adsorbed on the liquid cut-off plate; the first flushing pipe and the second flushing pipe of the distribution plate flush the coal powder adsorbed on the inner wall of the distribution plate, the cyclone separation device, the liquid cut-off plate, and the coal powder purification section, and flows out through the first outlet and the second outlet on the side of the liquid cut-off plate;

[0011] 3) The coal gas enters the primary cooling stage, where most of the naphthalene in the coal gas is removed while cooling the coal gas;

[0012] 4) The coal gas enters the second stage of coal powder purification, and the internal circulating ammonia water is sprayed to absorb the coal powder and naphthalene remaining in the coal gas, and flows to the bottom along the inner wall of the second stage of coal powder purification under the action of the cyclone separation device;

[0013] 5) The spraying liquid is divided into two paths at the third outlet. One path is transported by the flushing circulation pump to the upper part of the low-temperature water in the first stage of coal powder purification and the primary cooling stage to flush the adsorbed coal powder in the first stage of coal powder purification; in the upper part of the low-temperature water in the primary cooling stage, the spraying liquid enters the third flushing pipe to flush the tar naphthalene mixture on the wall of the heat exchange tube; the flushing liquid of the two sections and the other spraying liquid of the second stage of coal powder purification are transported to the front end of the raw gas pipeline by the tail liquid circulation pump, and are recycled within the system without being discharged externally.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1) After the gas is purified for a period of time, the coal powder is removed and the temperature remains basically unchanged, so there is no waste of gas heat energy.

[0016] 2) Compared with the installation of primary coolers and direct cooling towers, it saves equipment, civil engineering investment, and site space, and has great economic and technical advantages, especially in the renovation of old factories.

[0017] 3) Reduce the blockage inside the primary cooler, reduce the flow resistance of the gas, reduce the fan load, and achieve obvious energy-saving effects.

[0018] 4) After the circulating ammonia water is sprayed to absorb the residual coal powder in the coal gas, it is also used as the flushing liquid for the low-temperature water section in the coal gas purification section and the primary cooling section. It is recycled and sent to the front end of the coal gas purification system without external discharge, which is energy-saving and environmentally friendly.

[0019] 5) The present invention has simple equipment, simple construction and operation, perfect and reasonable structure, reduced operation cost, small investment and low energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1It is a schematic diagram of the structure and process principle of the present invention.

[0021] In the figure: 1-distribution plate 2-cyclone separation device 3-first flushing pipe 4-liquid cut-off plate 5-second flushing pipe 6-circulating ammonia water spraying device 7-cyclone separation device 8-third flushing pipe 9-flushing circulation pump 10-tail liquid circulation pump 11-first outlet 12-second outlet 13-third outlet 14-raw gas inlet 15-gas outlet DETAILED DESCRIPTION

[0022] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0023] Example:

[0024] like Figure 1 As shown, a coal gas cooling and purification combined treatment device is divided into three sections, which are coal powder purification section one, primary cooling section and coal powder purification section two from top to bottom, and also includes a flushing circulation pump 9 and a tail liquid circulation pump 10.

[0025] The first section of the coal powder purification is provided with a first flushing pipe 3, a distribution plate 1, a cyclone separation device 2, a second flushing pipe 5 and a liquid cut-off plate 4 from top to bottom. A raw gas inlet 14 is provided on the top of the body, and a first outlet 11 and a second outlet 12 are provided on the bottom side wall.

[0026] The primary cooling section is divided into three parts from top to bottom: a heating water section, a circulating water section and a low-temperature water section. The primary cooling section is provided with a third flushing pipe 8.

[0027] The second stage of the coal powder purification is provided with a circulating ammonia water spraying device 6 and a cyclone separation device 7 from top to bottom, and a coal gas outlet 15 and a third outlet 13 are provided on the bottom side wall of the second stage of the coal powder purification body.

[0028] The first outlet 11 and the second outlet 12 are connected to the tail liquid circulation pump 10 through pipelines respectively, the third outlet 13 is connected to the tail liquid circulation pump 10 through a branch pipeline, and the tail liquid circulation pump 10 is connected to the raw gas pipeline through a pipeline.

[0029] The first flushing pipe 3, the second flushing pipe 5, and the third flushing pipe 8 are connected to the flushing circulation pump 9 through pipelines respectively, and the third outlet 13 is connected to the flushing circulation pump 9 through another branch pipeline.

[0030] A combined treatment method for coal gas cooling and purification comprises the following steps:

[0031] 1) Raw coal gas enters from the raw coal gas inlet 14 at the top of the device, and enters the cyclone separation device 2 after passing through the distribution plate 1. The airflow carrying a large amount of coal powder is rotated and sprayed out. Due to the centrifugal force generated by the rotation of the gas and the gravity of the coal particles themselves, most of the coal particles are thrown to the inner wall of the coal powder purification section and adsorbed on the inner wall surface.

[0032] 2) The rotating jetted airflow collides with the liquid cut-off plate 4 when flowing downward, and some coal particles are adsorbed on the liquid cut-off plate 4. The first flushing pipe 3 and the second flushing pipe 5 flush the coal powder adsorbed on the distribution plate 1, the cyclone separation device 2, the liquid cut-off plate 4, and the inner wall of the first stage of coal powder purification, and flows out through the first outlet 11 and the second outlet 12 on the side of the liquid cut-off plate 4. Most of the coal powder in the coal gas in the first stage of coal powder purification is removed, and the temperature of the gas remains basically unchanged.

[0033] 3) After the coal powder purification stage, the coal gas enters the primary cooling stage. The primary cooling stage is divided into three parts from top to bottom: heating water section, circulating water section, and low-temperature water section. While cooling the coal gas, most of the naphthalene in the coal gas is removed.

[0034] 4) After the first stage of coal powder purification and the primary cooling stage, the large particles of coal powder and naphthalene in the coal gas are basically removed, but there are still fine coal powder and naphthalene remaining in the coal gas, which increases the difficulty of subsequent process treatment. A circulating ammonia water spraying device 6 and a cyclone separation device 7 are added to the third stage of coal powder purification. In the second stage of coal powder purification, the circulating ammonia water is continuously sprayed to absorb the coal powder and naphthalene remaining in the coal gas, and flows to the bottom of the body along the wall under the action of the cyclone separation device 7.

[0035] 5) At the third outlet 13, the spray liquid outlet pipe is divided into two paths. One path of spray liquid is transported by the flushing circulation pump 9 to the upper part of the low-temperature water in the first stage of coal powder purification and the primary cooling stage, and the adsorbed coal powder is flushed in the first stage of coal powder purification; in the upper part of the low-temperature water in the primary cooling stage, the spray liquid enters the flushing pipe 8 to flush the tar naphthalene mixture on the wall of the heat exchange tube; the flushing liquid of the two sections and the other spray liquid of the second purification section are transported to the front end of the raw gas pipeline by the tail liquid circulation pump 10, and are recycled in the system without being discharged externally.

[0036] The first stage of coal powder purification of the present invention separates a large amount of coal powder by cyclone, the primary cooling stage cools and purifies the coal gas, and the second stage of coal gas purification further separates coal powder and naphthalene by cyclone, and the spray liquid is recycled without external discharge, which is energy-saving and environmentally friendly. After the coal gas is purified for one stage, the coal powder is removed, the temperature remains basically unchanged, and there is no waste of coal gas thermal energy. Compared with the setting of a primary cooler and a direct cooling tower, it saves equipment and civil engineering investment, saves site space, and has great economic and technical advantages in the transformation of old factories. It reduces the blockage inside the primary cooler, reduces the flow resistance of coal gas, reduces the load of the fan, and has obvious energy-saving effect. After the circulating ammonia water is sprayed to absorb the residual coal powder in the coal gas, it is also used as the flushing liquid of the first stage of coal gas purification and the low-temperature water section in the primary cooling stage, recycled, and sent to the front end of the coal gas purification system without external discharge, which is energy-saving and environmentally friendly. The present invention has simple equipment, simple construction and operation, perfect and reasonable structure, reduces operating costs, requires less investment, and has low energy consumption.

[0037] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A combined treatment method for coal gas cooling and purification, characterized in that: A coal gas cooling and purification combined treatment device is adopted, the device is divided into three sections, namely, a coal powder purification section, a primary cooling section and a coal powder purification section 2 from top to bottom, and also includes a flushing circulation pump and a tail liquid circulation pump; the coal powder purification section 1 is provided with a first flushing pipe, a distribution plate, a cyclone separation device, a second flushing pipe and a liquid cut-off plate from top to bottom, a raw gas inlet is provided on the top of the body, and a first outlet and a second outlet are provided on the bottom side wall; the primary cooling section is divided into a heating water section, a circulating water section and a low-temperature water section from top to bottom, and the primary cooling section is provided with a third flushing pipe; the coal powder purification section 2 is provided with a circulating ammonia water spraying device and a cyclone separation device from top to bottom, and the coal powder purification section 2 is provided with a coal gas outlet and a third outlet on the bottom side wall of the body; The first outlet and the second outlet are connected to the tail liquid circulation pump through pipelines respectively, the third outlet is connected to the tail liquid circulation pump through a pipeline, and the tail liquid circulation pump is connected to the raw gas pipeline through a pipeline; The first flushing pipe, the second flushing pipe, and the third flushing pipe are respectively connected to the flushing circulation pump through pipelines, and the third outlet is connected to the flushing circulation pump through a pipeline; The specific steps include: 1) Raw coal gas enters the coal powder purification section from the raw coal gas inlet, and enters the cyclone separation device after passing through the distribution plate. The airflow carrying a large amount of coal powder is swirled out. Under the centrifugal force generated by the gas rotation and the gravity of the coal particles themselves, most of the coal particles are thrown to the inner wall of the coal powder purification section and adsorbed on the inner wall surface; 2) The rotating jetted airflow collides with the liquid cut-off plate when flowing downward, and some coal particles are adsorbed on the liquid cut-off plate; the first flushing pipe and the second flushing pipe flush the coal powder adsorbed on the inner wall of the distribution plate, the cyclone separation device, the liquid cut-off plate, and the coal powder purification section, and flows out through the first outlet and the second outlet on the side of the liquid cut-off plate; 3) The coal gas enters the primary cooling stage, where most of the naphthalene in the coal gas is removed while cooling the coal gas; 4) The coal gas enters the second stage of coal powder purification, and the internal circulating ammonia water is sprayed to absorb the coal powder and naphthalene remaining in the coal gas, and flows to the bottom along the inner wall of the second stage of coal powder purification under the action of the cyclone separation device; 5) The spraying liquid is divided into two paths at the third outlet. One path is transported by the flushing circulation pump to the upper part of the low-temperature water in the first stage of coal powder purification and the primary cooling stage to flush the adsorbed coal powder in the first stage of coal powder purification; in the upper part of the low-temperature water in the primary cooling stage, the spraying liquid enters the third flushing pipe to flush the tar naphthalene mixture on the wall of the heat exchange tube; the flushing liquid of the two sections and the other spraying liquid of the second stage of coal powder purification are transported to the front end of the raw gas pipeline by the tail liquid circulation pump, and are recycled within the system without being discharged externally.

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