A process method and process system for collaborative treatment of high-temperature raw coal gas for oil and gas separation, ammonia washing and dehumidification

Abstract

The present invention provides a process method and a process system for synergistically treating high-temperature raw coke oven gas for oil-gas separation, ammonia washing and dehumidification. The above method sequentially includes a dust removal treatment step, a pre-cooling treatment step, a washing treatment step, a tar fog removal treatment step, an ammonia washing treatment step and a dehumidification treatment step. The above system includes a dust collector, a pre-cooler, a washing tower, an electric tar precipitator, an ammonia washing tower and a dehumidification tower connected in sequence. The present invention adopts the purification process sequence of gas-solid separation, oil-gas separation, ammonia washing and dehumidification of raw coke oven gas, so that the pollutant content in the coal water generated by gas dehumidification is greatly reduced, the investment in the coal water treatment device is reduced, and the treatment cost is reduced. It solves the technical problems of high production cost and low energy utilization rate in the purification process of high-temperature raw coke oven gas in the prior art.

Description

Technical Field

[0001] The present invention relates to oil and gas separation and purification technologies, and in particular to a process method and a process system for synergistically treating high-temperature raw coke oven gas for oil and gas separation, ammonia washing, and dehumidification, belonging to the technical field of coal chemical industry. Background Art

[0002] The gas generated during the pyrolysis of coking coal or low-rank coal during carbonization is called high-temperature raw coke oven gas; the temperature of high-temperature raw coke oven gas is generally 550 - 650 °C. High-temperature raw coke oven gas contains a large amount of impurities such as dust, oil and gas, ammonia, and hydrogen sulfide; at the same time, the moisture in the coal material (8 - 12% is called coal water) vaporizes and mixes with the high-temperature raw coke oven gas. Currently, high-temperature raw coke oven gas is adiabatically cooled to about 80 - 85 °C by spraying ammonia water; the saturated gas is then indirectly cooled to 25 - 30 °C by a primary cooler, and the tar and water vapor in the gas condense into an oil-water mixture and are discharged to a tar-ammonia separation tank for oil-water separation. The cooled gas is pressurized by a fan and sent to an ammonium sulfate unit for ammonia washing. The tar-ammonia separation tank separates tar residue, tar, and coal water (remaining ammonia water). Since the raw coke oven gas contains a large amount of impurities such as dust, oil and gas, ammonia, and hydrogen sulfide, the coal water (remaining ammonia water) separated from the oil and water contains impurities such as ammonia, hydrogen sulfide, hydrogen cyanide, and organic aromatic hydrocarbons. The separated coal water is sent to a subsequent sewage treatment device for solvent extraction, ammonia distillation, biochemical, and membrane filtration treatment processes. Currently, this coal gas purification process flow is commonly used in the coal chemical industry, and its characteristics are mature technology and rich operation experience. The main problems existing in this process flow are: (1) The heat of high-temperature raw coke oven gas is not effectively utilized; (2) The coal water (remaining ammonia water) contains high concentrations of pollutants such as ammonia, hydrogen sulfide, hydrogen cyanide, and aromatic hydrocarbons, and the process for treating coal water is long, the operation cost is high, and it is difficult to meet the discharge standards.

[0003] Currently, the coal chemical industry urgently needs new process technologies that can solve the above problems, change the current situation of the coal gas purification process in the coal chemical industry, save energy consumption, and improve the environmental protection level. Summary of the Invention

[0004] The purpose of the present invention is to propose a process method and a process system for synergistically treating high-temperature raw coke oven gas for oil and gas separation, ammonia washing, and dehumidification in view of the problems of high production cost and low energy utilization rate in the process of purifying and treating high-temperature raw coke oven gas, so as to achieve low-cost and more reasonable purification and treatment of high-temperature raw coke oven gas.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] The technical purpose of the first aspect of the present invention is to provide a process method for synergistically treating high-temperature raw coke oven gas for oil and gas separation, ammonia washing, and dehumidification, which sequentially includes a dust removal treatment step, a pre-cooling treatment step, a washing treatment step, a tar fog removal treatment step, an ammonia washing treatment step, and a dehumidification treatment step.

[0007] Further, in the dust removal treatment step, the dust concentration in the high-temperature raw coke oven gas is reduced to ≤0.5 g / m 3 , and its temperature is maintained above 450 °C; in the precooling treatment step, the raw coke oven gas is cooled to 155 - 165 °C, preferably 160 °C; in the washing treatment step, the raw coke oven gas is successively subjected to oil washing and water washing, so that the tar content in the raw coke oven gas is <1 - 2 g / m 3 ; in the tar mist removal treatment step, an electrostatic tar precipitator is used to reduce the tar content in the raw coke oven gas to <30 mg / m 3 ; in the ammonia washing treatment step, ammonium sulfate mother liquor or phosphoric acid is used as the absorption liquid to absorb ammonia in the raw coke oven gas; in the dehumidification treatment step, the raw coke oven gas is condensed to 23 - 28 °C for dehydration to obtain purified raw coke oven gas.

[0008] Further, as a more specific embodiment, the process method includes the following steps:

[0009] Step 1, dust removal treatment: The high-temperature raw coke oven gas is subjected to dust removal treatment to make its dust concentration ≤0.5 g / m 3 , and the temperature of the raw coke oven gas after dust removal treatment is maintained above 450 °C, preferably 550 - 500 °C;

[0010] Step 2, precooling treatment: The raw coke oven gas after dust removal is precooled to remove tar. The temperature of the raw coke oven gas after precooling is controlled at 155 - 165 °C, preferably 160 °C, and the tar content in the raw coke oven gas after precooling treatment is <20 g / m 3 ;

[0011] Step 3, washing treatment: The raw coke oven gas after precooling treatment is successively subjected to oil washing and water washing. Tar is used as the wash oil for oil washing to absorb tar fractions such as uncondensed phenol oil, light oil, and heavy benzene in the raw coke oven gas, and the initial temperature of the wash oil in contact with the raw coke oven gas is 1 - 5 °C higher than the dew point of the raw coke oven gas, preferably 3 °C; the water washing is to wash the raw coke oven gas with ammonia water to remove the oil mist entrained in the raw coke oven gas, and the initial temperature of the ammonia water in contact with the raw coke oven gas is 1 - 5 °C higher than the dew point of the raw coke oven gas, preferably 1 °C. After the washing treatment, the tar content in the raw coke oven gas is <1 - 2 g / m 3 ;

[0012] Step 4, tar mist removal treatment: The raw coke oven gas after washing treatment is treated with an electrostatic tar precipitator to remove the tar mist in the raw coke oven gas under the action of an electrostatic field, and the tar content in the raw coke oven gas is reduced to <30 mg / m 3 ;

[0013] Step 5, ammonia washing treatment: After the tar fog removal treatment, the raw coke oven gas is subjected to ammonia washing treatment. The operating temperature for ammonia washing is 65 - 68°C. The ammonium sulfate mother liquor is used as the absorption liquid to contact the raw coke oven gas countercurrently to absorb the ammonia in it. Part of the used ammonium sulfate mother liquor is crystallized, and part of the crystallized mother liquor exchanges heat with the remaining used ammonium sulfate mother liquor and then returns to the crystallizer. The heat-exchanged ammonium sulfate mother liquor is used for circulating ammonia washing, and part of it is discharged and enters the crystallization separation device;

[0014] Step 6, dehumidification treatment: The raw coke oven gas after ammonia washing treatment is condensed to 23 - 28°C for dehydration to obtain purified raw coke oven gas.

[0015] Further, the dust removal treatment in Step 1 includes at least two - stage dust removal. Those skilled in the art should understand that generally, the dust concentration in high - temperature raw coke oven gas can be as high as 40 - 60 g / m 3 , and those skilled in the art can select the dust removal technology in the existing technology according to the dust removal effect to finally achieve the technical index that the dust concentration in the raw coke oven gas after dust removal ≤ 0.5 g / m 3 . As a specific implementation method, the dust removal treatment includes two - stage dust removal treatment. The first - stage dust removal treatment adopts a cyclone plate diversion and variable - diameter dust removal chamber structure, and the second - stage dust removal treatment adopts a dust removal process integrating gravity moving particle bed technology and fluidized bed elutriation technology to achieve the above - mentioned technical index.

[0016] Further, both the dust collector and the gas transportation pipeline used in the above - mentioned dust removal treatment adopt a hot - air jacket heat - preservation structure to ensure that the temperature of the high - temperature raw coke oven gas after dust removal treatment is 450°C higher than the oil - gas condensation temperature.

[0017] Further, the precooling in Step 2 adopts a horizontal tube indirect cooling method, and the cooling medium is heat - conducting oil. The heat - conducting oil is heated from about 130°C initially to about 230°C, and the heated heat - conducting oil is sent to the waste heat recovery device.

[0018] Those skilled in the art should understand that generally, the tar content in high - temperature raw coke oven gas is related to the coal material and the pyrolysis process. For example, the tar content in coke oven raw coke oven gas is 100 - 120 g / m 3 , and the low - temperature pyrolysis raw coke oven gas contains 300 - 400 g / m of tar 3 . Through the precooling in Step 2, by controlling the precooling end - point temperature, the tar content in the raw coke oven gas is reduced to < 20 g / m 3 .

[0019] Further, the oil washing in Step 3 is carried out by using a washing oil spraying method to contact the raw coke oven gas countercurrently. Preferably, fillers are added during the oil washing process to increase the residence time of the raw coke oven gas and achieve more thorough oil washing.

[0020] Those skilled in the art should understand that after pre-cooling treatment, most of the tar in the raw coke oven gas is removed. Before washing treatment, the raw coke oven gas contains about 10-15 g / m of phenol oil, light oil and crude benzene. 3 , and after washing treatment, the tar content in the gas is reduced to <1-2 g / m 3 .

[0021] Further, in the ammonia washing treatment in step five, the mass concentration of sulfuric acid in the ammonium sulfate mother liquor is 2-4%, and sulfuric acid is continuously added during the ammonia washing process to maintain this concentration range.

[0022] Further, the operating temperature of ammonia washing is coordinately controlled according to the balance among the water vapor content in the raw coke oven gas, the amount of water vapor condensation during ammonia washing, and the water evaporation amount of the vacuum crystallizer;

[0023] Further, the operating temperature of the crystallizer is 50-52 °C, and the pressure is 13 kPa (absolute pressure); after heat exchange, the temperature of the ammonium sulfate mother liquor is cooled from 65-68 °C to 57-61 °C, and the temperature of the crystallized mother liquor is increased from 50-52 °C to 55-57 °C.

[0024] Further, in the ammonia washing treatment step, if phosphoric acid is used as the absorption liquid, ammonia in the raw coke oven gas is absorbed by phosphoric acid to generate ammonium hydrogen phosphate, and the rich phosphonium liquid is desorbed to produce ammonia water.

[0025] Further, after the aforementioned deoiling and ammonia washing treatments, in step six of the dehumidification treatment, the NH3 content in the coal water generated by the condensation of water vapor in the raw coke oven gas is <30 mg / L, the COD is <800 mg / L, and it does not contain H2S, HCN and polycyclic organic aromatic hydrocarbons that are difficult to degrade, and it can meet the discharge standard after simple wastewater treatment.

[0026] Further, the dehumidification treatment adopts a horizontal tube indirect cooling method with water as the cooling medium.

[0027] Another object of the present invention also discloses a process system for synergistic treatment of high-temperature raw coke oven gas oil-gas separation, ammonia washing and dehumidification, including a dust collector, a pre-cooler, a washing tower, an electric tar precipitator, an ammonia washing tower and a dehumidification tower connected in sequence; wherein, the washing tower is fed at the bottom and discharged at the top, the lower half is an oil washing section, the upper half is a water washing section, the bottom of the oil washing section is externally connected to an oil washing pump and is connected to the top of the oil washing section through an oil washing cooler; the bottom of the water washing section is externally connected to an ammonia water pump and is connected to the top of the water washing section.

[0028] Further, the bottom of the ammonia washing tower is also externally connected to an ammonium sulfate mother liquor pump, which is provided with branches. The first branch is connected to the mother liquor cooler and then returns to the top of the ammonia washing tower, and the second branch is connected to the crystallizer. The discharge port of the crystallizer is connected to the mother liquor cooler through a crystallized mother liquor pump and then returns to the crystallizer, and the crystallizer is also externally connected to a vacuum pump.

[0029] Further, the dust collector includes a primary dust collector and a secondary dust collector connected in sequence. The primary dust collector is a dust collector with a swirl plate for flow guiding and a variable-diameter dust chamber structure, and the secondary dust collector is a dust collector integrating the gravity moving particle bed technology and the fluidized bed elutriation technology. The filter media outlet of the secondary dust collector is connected to the fluidized bed inlet, and the filter media at the fluidized bed filter media outlet is sent to the filter media inlet of the secondary dust collector through a lifting device.

[0030] Further, the pre-cooler is a condensation tower using the indirect tube cooling method, with feed at the top of the tower and discharge at the bottom of the tower. A coke oil pump is externally connected to the bottom of the tower to partially discharge the tar removed from the raw coal gas and partially recycle it to the sprayer at the top of the tower.

[0031] Further, the oil washing section is filled with packing, which can increase the contact time between the raw coal gas and the wash oil to achieve more thorough tar elution.

[0032] Further, sprayers are respectively arranged at the tops of the oil washing section and the water washing section of the washing tower.

[0033] Further, the ammonia washing tower is a spray tower, with feed at the bottom of the tower and discharge at the top of the tower. The raw coal gas in the tower contacts the absorption liquid in a countercurrent manner.

[0034] Further, the dehumidification tower is a cooling tower using the indirect tube cooling method, with feed at the top of the tower and discharge at the bottom of the tower.

[0035] Further, a blower is externally connected to the dehumidification tower to collect and transport the treated clean raw coal gas.

[0036] The process method and process system for the coordinated treatment of high-temperature raw coal gas for oil-gas separation, ammonia washing, and dehumidification of the present invention have the following advantages compared with the prior art:

[0037] 1) The present invention adopts the purification process sequence of gas-solid separation, oil-gas separation, ammonia washing, and dehumidification of the raw coal gas, which greatly reduces the pollutant content in the coal water generated by gas dehumidification, reduces the investment in the coal water treatment device, and reduces the treatment cost.

[0038] 2) The present invention arranges the process of cooling and recovering tar after the high-temperature raw coal gas dust removal process, reduces the solid particle content in the tar, and simplifies the subsequent tar processing process.

[0039] 3) The present invention adopts the thermal method for ammonia washing. The operating temperature of the ammonia washing tower is controlled at the gas dew point temperature, and the ammonia washing effect is good. The ammonium sulfate mother liquor is crystallized under vacuum to extract ammonium sulfate, fully realizing waste recycling.

[0040] 4) The present invention first removes the dust in the high-temperature raw coal gas and separates the tar in the gas by cooling and washing, solving the technical problem of difficult separation of the solid, oil, and water phases in the subsequent gas purification process.

[0041] It should be understood that the terms and expressions used herein are for the purpose of description and not of limitation. Thus, based on what is known, those skilled in the art in this field can understand these concepts and easily design other structures, methods, and systems to achieve several objects of the present invention. Importantly, it can be considered that the claims include equivalent structures as long as they do not depart from the spirit and scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of a process system for the collaborative treatment of high-temperature raw coke oven gas for oil-gas separation, ammonia washing, and dehumidification in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] The present invention will be further described below in conjunction with embodiments:

[0044] Example 1

[0045] This example discloses a process system for the collaborative treatment of high-temperature raw coke oven gas for oil-gas separation, ammonia washing, and dehumidification, as Figure 1 shown, including a primary dust collector 10, a secondary dust collector 20, a pre-cooling tower 30, a washing tower 40, an electric tar precipitator 50, an ammonia washing tower 60, and a dehumidification tower 70 connected in sequence;

[0046] Among them, the primary dust collector 10 adopts a swirl plate diversion and variable-diameter dust removal chamber structure, and the secondary dust collector 20 is a gravity moving particle bed filled with filter media. It is also connected to a fluidized bed 21, and the used filter media can be output to the fluidized bed for purification treatment;

[0047] The pre-cooling tower 30 is an inter-pipe cooling tower with cooling medium tar as heat transfer oil flowing through it. A raw coke oven gas inlet is provided at the top, a raw coke oven gas outlet is provided at the lower part, and a coke oil pump 31 is also externally connected at the bottom to discharge part of the removed tar and circulate part of it to the sprayer at the top of the tower;

[0048] The washing tower 40 is divided into two sections. The lower half is an oil washing section 41, and the upper half is a water washing section 44. The raw coke oven gas feed inlet is provided at the lower part of the oil washing section 41, and the outlet is provided at the top of the tower. Sprayers are respectively configured at the tops of the two sections. Packing is also filled in the oil washing section 41. A washing oil pump 42 is externally connected to the bottom of the oil washing section 41 and is connected to the sprayer of the oil washing section 41 through an oil washing cooler 43; A ammonia water pump 45 is externally connected to the bottom of the water washing section 44 and is connected to the sprayer of the water washing section 44;

[0049] The ammonia scrubber 60 is a spray tower. The raw coke oven gas inlet is arranged at the bottom of the tower, and the outlet is arranged at the top of the tower. A sprayer is also arranged at the top of the tower. Inside the tower, the raw coke oven gas contacts the mother liquor countercurrently; the bottom of the ammonia scrubber 60 is externally connected to an ammonium sulfate mother liquor pump 61, which has branches. The first branch returns to the top of the ammonia scrubber after connecting to the mother liquor cooler 62, and the second branch connects to the crystallizer 63. The outlet of the crystallizer 63 is connected to the mother liquor cooler 62 through a crystallized mother liquor pump 64 and then returns to the crystallizer 63. The crystallizer 63 is also externally connected to a vacuum pump 65;

[0050] The dehumidification tower 70 is an intermediate tube cooling tower, with cooling medium water flowing through it. The raw coke oven gas inlet is arranged at the top, and the raw coke oven gas outlet is arranged at the lower part. A condensate drain outlet is also arranged at the bottom; the raw coke oven gas outlet is also connected to a blower 71 to collect and transport the treated clean raw coke oven gas.

[0051] Example 2

[0052] This example discloses a process method for purifying raw coke oven gas using the above process system, including the following steps:

[0053] Step 1, dust removal treatment: The high-temperature raw coke oven gas discharged from the coke oven carbonization chamber is sequentially passed through a primary dust collector 10 and a secondary dust collector 20 for dust removal treatment. The temperature of the high-temperature raw coke oven gas entering the dust removal device is 600 °C, and the dust concentration is 55 g / m 3 , and the temperature of the raw coke oven gas at the outlet of the dust collector is 510 °C, and the dust concentration ≤ 0.5 g / m 3 ;

[0054] Step 2, precooling treatment: The dust-removed raw coke oven gas is passed through a precooling tower 30 for precooling and tar removal. The temperature of the precooled raw coke oven gas is controlled at 160 °C. The tar content in the precooled raw coke oven gas < 20 g / m 3 ; The removed tar is pumped out by a tar pump 31, with part discharged externally and part recycled to the sprayer at the top of the precooling tower 30;

[0055] Step 3, washing treatment: The precooled raw coke oven gas is passed into the bottom of the washing tower 40 and sequentially passes through an oil washing section 41 and a water washing section 44. The oil washing uses tar as the washing oil to absorb tar fractions such as uncondensed phenol oil, light oil, and heavy benzene in the raw coke oven gas, and the initial temperature of the washing oil in contact with the raw coke oven gas is kept 3 °C higher than the dew point of the raw coke oven gas; the water washing is to wash the raw coke oven gas with ammonia water to remove the oil mist entrained in the raw coke oven gas. The initial temperature of the ammonia water in contact with the raw coke oven gas is 1 °C higher than the dew point of the raw coke oven gas. After the washing treatment, the tar content in the raw coke oven gas < 1 - 2 g / m 3 ;

[0056] Step 4, tar mist removal treatment: The raw coke oven gas after the washing treatment is passed through an electrostatic tar precipitator 50 for treatment, and the tar mist in the raw coke oven gas is removed under the action of an electrostatic field. The tar content in the raw coke oven gas is reduced to < 30 mg / m 3 ;

[0057] Step Five, ammonia washing treatment: After the tar fog removal treatment, the raw coal gas is introduced into the ammonia washing tower 60 for ammonia washing treatment. The operating temperature for ammonia washing is 65 - 68°C. Using ammonium sulfate mother liquor (sulfuric acid mass concentration 3%) as the absorption liquid, it contacts the raw coal gas countercurrently to absorb the ammonia in it. Part of the used ammonium sulfate mother liquor is introduced into the crystallizer 63 for crystallization. The operating temperature of the crystallizer 63 is 50 - 52°C, and the pressure is 13 kPa (absolute pressure). Part of it returns to the top of the ammonia washing tower after passing through the mother liquor cooler 62 for circulating ammonia washing of the heat-exchanged ammonium sulfate mother liquor. Part of the crystallized mother liquor in the crystallizer 63 is pumped to the mother liquor cooler 62 by the crystallized mother liquor pump 64, returns to the crystallizer 63 after heat exchange with the ammonium sulfate mother liquor, and part is discharged into the crystallization separation device; in the above process, the temperature of the ammonium sulfate mother liquor is cooled from 65 - 68°C to 57 - 61°C, and the crystallized mother liquor is heated from 50 - 52°C to 55 - 57°C;

[0058] Step Six, dehumidification treatment: The raw coal gas after ammonia washing treatment is introduced into the dehumidification tower 70 and condensed to 23 - 28°C for dehydration to obtain purified raw coal gas. The content of NH3 in the coal water generated by the condensation of water vapor in the raw coal gas is < 30 mg / L, COD < 800 mg / L, and it does not contain H2S, HCN, and hardly degradable polycyclic organic aromatic hydrocarbons, and it can meet the discharge standard after simple wastewater treatment.

[0059] Finally, it should be noted that: The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process method for synergistically treating high-temperature raw coke oven gas for oil-gas separation, ammonia washing, and dehumidification It is characterized in that It includes the following steps: Step 1, dust removal treatment: Perform dust removal treatment on the high-temperature raw coal gas to make its dust concentration ≤ 0.5 g / m 3 , and keep the temperature of the raw coal gas after dust removal treatment above 450 °C; Step 2, pre-cooling treatment: Pre-cool the raw coal gas after dedusting to remove tar. The temperature of the raw coal gas after pre-cooling is controlled at 155-165°C, and the tar content in the raw coal gas after pre-cooling treatment is <20 g / m 3 ; Step 3, washing treatment: The pre-cooled raw coal gas is successively subjected to oil washing and water washing. Tar is used as the wash oil for the oil washing to absorb the uncondensed phenol oil, light oil and heavy benzene in the raw coal gas, and the initial temperature of the wash oil in contact with the raw coal gas is maintained 1-5°C higher than the dew point of the raw coal gas; the water washing is to wash the raw coal gas with ammonia water to remove the oil mist entrained in the raw coal gas, and the initial temperature of the ammonia water in contact with the raw coal gas is 1-5°C higher than the dew point of the raw coal gas. After the washing treatment, the tar content in the raw coal gas is <2 g / m 3 ; Step 4, tar mist treatment: The raw coal gas after washing treatment is processed by an electrostatic tar precipitator to remove the tar mist in the raw coal gas under the action of an electrostatic field, and the tar content in the raw coal gas is reduced to <30 mg / m 3 ; Step 5, ammonia washing treatment: After the tar fog removal treatment, the raw coke oven gas is subjected to ammonia washing treatment. The operating temperature of ammonia washing is 65 - 68°C. The ammonium sulfate mother liquor is used as the absorption liquid to contact the raw coke oven gas countercurrently to absorb the ammonia in it. Part of the used ammonium sulfate mother liquor is crystallized. The crystallized mother liquor part exchanges heat with the remaining part of the used ammonium sulfate mother liquor and then returns to the crystallizer. The heat-exchanged ammonium sulfate mother liquor is used for circulating ammonia washing, and part of it is discharged into the crystallization separation device; Step 6, dehumidification treatment: The raw coke oven gas after ammonia washing treatment is condensed to 23 - 28°C for dehydration to obtain purified raw coke oven gas; The process system adopted by the process method for the collaborative treatment of high-temperature raw coke oven gas oil-gas separation, ammonia washing and dehumidification includes: a dust collector, a pre-cooler, a washing tower, an electrostatic tar precipitator, an ammonia washing tower and a dehumidification tower connected in sequence; among them, the washing tower is fed at the bottom and discharged at the top. The lower half of it is an oil washing section, and the upper half is a water washing section. The bottom of the oil washing section is externally connected to an oil washing pump and is connected to the top of the oil washing section through an oil cooler; the bottom of the water washing section is externally connected to an ammonia water pump and is connected to the top of the water washing section; The bottom of the ammonia washing tower is also externally connected to an ammonium sulfate mother liquor pump. The ammonium sulfate mother liquor pump is provided with branches. The first branch returns to the top of the ammonia washing tower after connecting to the mother liquor cooler, and the second branch is connected to the crystallizer. The discharge port of the crystallizer is connected to the mother liquor cooler through a crystallized mother liquor pump and then returns to the crystallizer. The crystallizer is also externally connected to a vacuum pump; The dust collector includes a primary dust collector and a secondary dust collector connected in sequence. The primary dust collector is a dust collector with a swirl plate diversion and variable-diameter dust removal chamber structure, and the secondary dust collector is a dust collector integrating gravity moving particle bed technology and fluidized bed elutriation technology; The pre-cooler is a condensation tower using an inter-tube cooling method, fed at the top and discharged at the bottom. The bottom is externally connected to a coke oven gas pump to discharge part of the tar removed from the raw coke oven gas and circulate part of it to the sprayer at the top; 2. The process method according to claim 1, characterized in that, The oil washing in Step 3 is to contact the raw coke oven gas countercurrently by means of oil washing spray, and fillers are added during the oil washing process.

3. The process method according to claim 1, characterized in that, The operating temperature of the crystallizer in Step 5 is 50 - 52°C, and the pressure is 13 kPa; after heat exchange, the temperature of the ammonium sulfate mother liquor is cooled from 65 - 68°C to 57 - 61°C, and the temperature of the crystallized mother liquor is raised from 50 - 52°C to 55 - 57°C.

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