Raw gas cooling and purifying system and process

Abstract

The invention discloses a raw gas cooling and purifying system and process. The system comprises a cooling and purifying module, an ammonia washing and purifying module and an ammonia water recycling module, the raw gas outlet end of the cooling and purifying module is in fluid communication with the raw gas inlet end of the ammonia washing and purifying module, and the steam outlet end of the cooling and purifying module is in fluid communication with the steam inlet end of the ammonia water recycling module; the ammonia water outlet end of the ammonia washing purification module is in fluid communication with the ammonia water inlet end of the ammonia water recovery module; heavy tar and medium oil in the raw coke oven gas are separated and collected in the cooling and purifying module, the raw coke oven gas discharged from the cooling and purifying module enters the ammonia washing and purifying module to be cooled, a light oil product is separated, and steam generated by the cooling and purifying module enters the ammonia water recycling module to be recycled; ammonia water discharged by the ammonia washing purification module enters the ammonia water recovery module for distillation recovery treatment. The invention can solve the problems of low heat recovery rate, poor oil separation effect, high circulating cooling water consumption and the like in the existing raw gas cooling and purifying process.

Description

Technical Field

[0001] The present invention relates to the technical field of raw gas purification, and more particularly to a raw gas cooling and purification system and process. Background Art

[0002] The steel and coal chemical industries are pillar industries in my country and are of great significance to national development. In recent years, under the national "dual carbon" policy, energy conservation and carbon reduction have become key goals for the future development of these two sectors. According to the specific requirements for the energy efficiency benchmark for coke oven processes in the national standard GB21342-2013, only 2% of the domestic coking industry's coke oven production capacity currently exceeds the benchmark, while over 40% of the capacity falls below the benchmark. Therefore, energy conservation and carbon reduction efforts in coke oven production processes are not only of great significance but also offer significant potential for further development.

[0003] Statistics show that during the entire coke oven production process, 32%-36% of the heat is carried away by high-temperature raw gas. If fully utilized, this heat could reduce energy consumption by over 15kgce / t and CO2 emissions by over 40kg / t. In existing coke oven production processes, the raw gas produced reaches temperatures of 800-1200°C. Currently, the industry's primary cooling and purification process for this raw gas is to directly cool it to 80-90°C using a circulating ammonia spray method before feeding it into subsequent raw gas refining processes.

[0004] In this process, not only is a large amount of heat from the raw gas not fully recovered and utilized, but a large amount of circulating cooling water is consumed to exchange heat for the circulating ammonia. Furthermore, due to the direct spraying of the circulating ammonia, oil products such as tar, phenols, and polycyclic aromatic compounds in the raw gas enter the circulating ammonia, greatly increasing the difficulty of separating and recovering these oil products, and increasing the difficulty and cost of subsequent treatment of the remaining ammonia. Against this backdrop, there is an urgent need to develop a raw gas cooling and purification process with higher resource and energy utilization rates to improve the energy efficiency of the coking process. Summary of the Invention

[0005] To this end, the technical problem to be solved by the present invention is to provide a raw gas cooling and purification system and process, which can not only greatly recover the energy in the raw gas and reduce the use of circulating cooling water, but also greatly improve the water quality of the residual ammonia water, reduce the energy consumption and difficulty of subsequent wastewater treatment, thereby solving the existing problems of low raw gas heat recovery rate, poor tar oil separation effect, high circulating cooling water consumption, and poor residual ammonia water quality.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A raw gas cooling and purification system comprises a cooling and purification module, an ammonia washing and purification module, and an ammonia water recovery module; the raw gas outlet of the cooling and purification module is in fluid communication with the raw gas inlet of the ammonia washing and purification module, the steam outlet of the cooling and purification module is in fluid communication with the steam inlet of the ammonia water recovery module; the ammonia water outlet of the ammonia washing and purification module is in fluid communication with the ammonia water inlet of the ammonia water recovery module;

[0008] In the cooling and purification module, heavy tar and medium oil in the raw gas are separated and collected, and the raw gas discharged from the cooling and purification module enters the ammonia washing purification module, and the steam generated by the cooling and purification module enters the ammonia water recovery module for reuse; after being processed by the ammonia washing purification module, the light oil in the raw gas is separated and collected, and the raw gas discharged from the ammonia washing purification module enters the subsequent processing unit, and the ammonia water discharged from the ammonia washing purification module enters the ammonia water recovery module for distillation recovery treatment.

[0009] The above-mentioned raw gas cooling and purification system, the cooling and purification module includes a quenching oil tower, a quenching oil tower bottom delivery pump, a quenching oil tower first heat exchanger, a clarifier, a quenching oil tower lower section circulation pump, a heavy tar effluent pump, a quenching oil tower upper section circulation pump and a quenching oil tower second heat exchanger;

[0010] The quenching oil tower includes an upper circulating oil tower and a lower circulating oil tower; the raw gas outlet of the coke oven riser is fluidly connected to the raw gas inlet of the lower circulating oil tower, the raw gas outlet of the lower circulating oil tower is fluidly connected to the raw gas inlet of the upper circulating oil tower, and the raw gas outlet of the upper circulating oil tower is fluidly connected to the raw gas inlet of the ammonia washing purification module; in the quenching oil tower, the raw gas and circulating oil flow in opposite directions;

[0011] The circulating oil outlet of the lower circulating oil tower is in fluid communication with the circulating oil inlet of the bottom delivery pump of the quenching oil tower, the circulating oil outlet of the bottom delivery pump of the quenching oil tower is in fluid communication with the circulating oil inlet of the first heat exchanger of the quenching oil tower, the circulating oil outlet of the first heat exchanger of the quenching oil tower is in fluid communication with the circulating oil inlet of the clarification tank, the heavy tar outlet of the clarification tank is in fluid communication with the fluid inlet of the heavy tar efflux pump, the fluid outlet of the heavy tar efflux pump is in fluid communication with the fluid inlet end of the heavy tar product collecting device; the circulating oil outlet of the clarification tank is in fluid communication with the circulating oil inlet of the lower circulating oil tower; the heat exchange medium inlet of the first heat exchanger of the quenching oil tower is in fluid communication with the fluid outlet of the heat exchange medium, and the steam outlet of the first heat exchanger of the quenching oil tower is in fluid communication with the steam inlet of the ammonia recovery module;

[0012] The side line fluid outlet of the upper circulating oil tower is fluidly connected to the circulating oil inlet of the upper circulating pump of the quenching oil tower, the circulating oil outlet of the upper circulating pump of the quenching oil tower is fluidly connected to the circulating oil inlet of the second heat exchanger of the quenching oil tower, the circulating oil first outlet of the second heat exchanger of the quenching oil tower is fluidly connected to the circulating oil inlet of the upper circulating oil tower, the circulating oil second outlet of the second heat exchanger of the quenching oil tower is fluidly connected to the fluid inlet end of the petroleum product collection device; the heat exchange medium inlet of the second heat exchanger of the quenching oil tower is fluidly connected to the fluid outlet of the heat exchange medium, and the steam outlet of the second heat exchanger of the quenching oil tower is fluidly connected to the steam inlet of the ammonia recovery module.

[0013] The present invention divides the quenching oil tower into an upper circulating oil tower and a lower circulating oil tower, wherein the upper circulating oil tower and the lower circulating oil tower circulate light tar with a lower temperature and heavy tar with a higher temperature respectively; after the system is in operation, the circulating oil in the upper circulating oil tower and the lower circulating oil tower are collected from the raw gas according to different boiling point ranges, part of the oil collected from the raw gas is returned to the circulating oil tower, and part is discharged as a product; the additional circulating oil added when the system is started is also designed according to the oil composition in the raw gas, or the designed boiling point range of the oil. Compared to the full-section circulation of the quenching oil tower, the present invention divides the quenching oil tower into two sections for separate circulation, which has the following advantages: 1. The recovered oil product is more valuable, as the two mixed oil products (light oil and heavy oil) are collected separately; 2. The lower section circulating oil contains solid dust particles, which, when mixed with the lower section circulating oil, have good fluidity at high temperatures and are not prone to fouling and clogging equipment. If the two sections of circulating oil are mixed together, the circulating oil temperature will be too low, making the oil fluidity even worse and prone to fouling and clogging equipment; therefore, the oil products divided into two temperature sections are also beneficial for separating solid dust particles from raw gas. 3. The recovered heat is more valuable: After the upper and lower sections of circulating oil leave the quenching tower, heat exchange is required to recover heat. If the two sections of oil are combined, only a low-temperature oil product is obtained, and ultimately only low-grade, low-pressure steam can be separated. However, after the upper and lower circulating oil are separated in the present invention, the lower section circulating oil can separate medium-pressure steam of higher temperature and quality.

[0014] The above-mentioned raw gas cooling and purification system, the ammonia washing and purification module includes an ammonia washing tower, an ammonia water circulation tank, a circulating ammonia water washing pump and a circulating ammonia water cooler; the raw gas outlet end of the cooling and purification module is fluidly connected to the raw gas inlet end of the ammonia washing tower, and the raw gas outlet end of the ammonia washing tower is fluidly connected to the raw gas inlet end of the subsequent processing unit; in the ammonia washing tower, the raw gas and the circulating ammonia water flow in opposite directions;

[0015] The circulating ammonia water outlet of the ammonia washing tower is fluidly connected to the circulating ammonia water inlet of the ammonia water circulation tank, the circulating ammonia water first outlet of the ammonia water circulation tank is fluidly connected to the circulating ammonia water inlet of the circulating ammonia water elution pump, the circulating ammonia water outlet of the circulating ammonia water elution pump is fluidly connected to the circulating ammonia water inlet of the circulating ammonia water cooler, and the circulating ammonia water outlet of the circulating ammonia water cooler is fluidly connected to the circulating ammonia water inlet of the ammonia washing tower; the circulating ammonia water second outlet of the ammonia water circulation tank is fluidly connected to the ammonia water inlet end of the ammonia water recovery module; the light oil outlet of the ammonia water circulation tank is fluidly connected to the fluid inlet end of the light oil product collection device.

[0016] The above-mentioned raw gas cooling and purification system, the ammonia recovery module includes an ammonia still, an ammonia still raw material heat exchanger, an ammonia still top condenser, an ammonia buffer tank, an ammonia still reflux pump, an ammonia still feed pump and an ammonia still bottom discharge pump; the ammonia outlet end of the ammonia washing purification module is fluidly connected to the ammonia inlet of the ammonia still feed pump, the ammonia outlet of the ammonia still feed pump is fluidly connected to the ammonia inlet of the ammonia still raw material heat exchanger, and the ammonia outlet of the ammonia still raw material heat exchanger is fluidly connected to the ammonia inlet of the ammonia still The ammonia vapor outlet of the ammonia still tower is in fluid communication with the ammonia vapor inlet of the ammonia still tower top condenser, the condensed fluid outlet of the ammonia still tower top condenser is in fluid communication with the condensed fluid inlet of the ammonia aqueous buffer tank, the ammonia aqueous outlet of the ammonia aqueous buffer tank is in fluid communication with the ammonia aqueous inlet of the ammonia still tower reflux pump, the circulating ammonia aqueous outlet of the ammonia still tower reflux pump is in fluid communication with the circulating ammonia aqueous inlet of the ammonia still tower, and the recovered ammonia aqueous outlet of the ammonia still tower reflux pump is in fluid communication with the fluid inlet end of the ammonia aqueous collection device;

[0017] The ammonia evaporation wastewater outlet of the ammonia evaporation tower is in fluid communication with the ammonia evaporation wastewater inlet of the ammonia evaporation tower raw material heat exchanger, which is in fluid communication with the ammonia evaporation wastewater inlet of the ammonia evaporation tower bottom discharge pump, which is in fluid communication with the fluid inlet of the ammonia evaporation wastewater debiochemical system. The steam outlet of the cooling and purification module is in fluid communication with the steam inlet of the ammonia evaporation tower. The ammonia recovery module may also include an ammonia evaporation tower reboiler for heating materials within the ammonia evaporation tower.

[0018] The above-mentioned raw gas cooling and purification system, the ammonia washing purification module includes an ammonia washing tower, an ammonia water circulation tank, a circulating ammonia water elution pump and a circulating ammonia water cooler; the raw gas outlet of the upper circulating oil tower is fluidly connected to the raw gas inlet of the ammonia washing tower, and the raw gas outlet of the ammonia washing tower is fluidly connected to the raw gas inlet of the subsequent processing unit; in the ammonia washing tower, the raw gas and the circulating ammonia water flow in opposite directions;

[0019] The circulating ammonia water outlet of the ammonia scrubbing tower is in fluid communication with the circulating ammonia water inlet of the ammonia water circulation tank, the circulating ammonia water first outlet of the ammonia water circulation tank is in fluid communication with the circulating ammonia water inlet of the circulating ammonia water elution pump, the circulating ammonia water outlet of the circulating ammonia water elution pump is in fluid communication with the circulating ammonia water inlet of the circulating ammonia water cooler, and the circulating ammonia water outlet of the circulating ammonia water cooler is in fluid communication with the circulating ammonia water inlet of the ammonia scrubbing tower; the light oil outlet of the ammonia water circulation tank is in fluid communication with the fluid inlet end of the light oil product collecting device;

[0020] The ammonia recovery module includes an ammonia still, an ammonia still raw material heat exchanger, an ammonia still top condenser, an ammonia buffer tank, an ammonia still reflux pump, an ammonia still feed pump and an ammonia still bottom discharge pump; the circulating ammonia water second outlet of the ammonia circulation tank is fluidly connected to the ammonia water inlet of the ammonia still feed pump, the ammonia water outlet of the ammonia still feed pump is fluidly connected to the ammonia water inlet of the ammonia still raw material heat exchanger, the ammonia water outlet of the ammonia still raw material heat exchanger is fluidly connected to the ammonia water inlet of the ammonia still, and the ammonia still The ammonia vapor outlet of the tower is in fluid communication with the ammonia vapor inlet of the ammonia still column top condenser, the condensed fluid outlet of the ammonia still column top condenser is in fluid communication with the condensed fluid inlet of the ammonia aqueous buffer tank, the ammonia aqueous outlet of the ammonia aqueous buffer tank is in fluid communication with the ammonia aqueous inlet of the ammonia still column reflux pump, the circulating ammonia aqueous outlet of the ammonia still column reflux pump is in fluid communication with the circulating ammonia aqueous inlet of the ammonia still column, and the recovered ammonia aqueous outlet of the ammonia still column reflux pump is in fluid communication with the fluid inlet end of the ammonia aqueous collection device;

[0021] The ammonia evaporation wastewater outlet of the ammonia evaporation tower is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower raw material heat exchanger, the ammonia evaporation wastewater outlet of the ammonia evaporation tower raw material heat exchanger is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower bottom discharge pump, and the ammonia evaporation wastewater outlet of the ammonia evaporation tower bottom discharge pump is fluidly connected to the fluid inlet end of the ammonia evaporation wastewater biochemical system; the steam outlet of the first heat exchanger of the quenching oil tower is fluidly connected to the steam inlet of the ammonia evaporation tower, and the steam outlet of the second heat exchanger of the quenching oil tower is also fluidly connected to the steam inlet of the ammonia evaporation tower.

[0022] A raw gas cooling and purification process, which uses the above-mentioned raw gas cooling and purification system to cool and purify the raw gas, includes the following steps:

[0023] Step (1), using the cooling and purification module to cool the raw gas and separate solid particles, liquid and gas in the raw gas to obtain heavy tar products, medium oil products and preliminarily cooled and purified raw gas; steam obtained by heat exchange with the raw gas is used for ammonia distillation in the ammonia recovery module;

[0024] Step (2), using the ammonia washing purification module to perform circulating ammonia washing on the preliminarily cooled and purified raw gas, the preliminarily cooled and purified raw gas is washed with circulating ammonia water to obtain purified raw gas, the circulating ammonia water collected after washing is treated and separated to obtain a light oil product, a portion of the circulating ammonia water from which the light oil is removed is used for circulating ammonia washing of the raw gas, and a portion enters the ammonia water recovery module to distill and recover ammonia water;

[0025] Step (3): utilizing the ammonia recovery module to distill and recover the ammonia, and the ammonia wastewater enters the biochemical system for biochemical treatment.

[0026] In the above-mentioned raw gas cooling and purification process, in step (1), the cooling and purification module includes a quenching oil tower, a quenching oil tower bottom delivery pump, a quenching oil tower first heat exchanger, a clarifier, a quenching oil tower lower section circulation pump, a heavy tar effluent pump, a quenching oil tower upper section circulation pump and a quenching oil tower second heat exchanger;

[0027] The quenching oil tower includes an upper circulating oil tower and a lower circulating oil tower; the raw gas outlet of the coke oven riser is fluidly connected to the raw gas inlet of the lower circulating oil tower, and the raw gas outlet of the lower circulating oil tower is fluidly connected to the raw gas inlet of the upper circulating oil tower; in the quenching oil tower, the raw gas and circulating oil flow in opposite directions;

[0028] The circulating oil outlet of the lower circulating oil tower is in fluid communication with the circulating oil inlet of the bottom delivery pump of the quenching oil tower, the circulating oil outlet of the bottom delivery pump of the quenching oil tower is in fluid communication with the circulating oil inlet of the first heat exchanger of the quenching oil tower, the circulating oil outlet of the first heat exchanger of the quenching oil tower is in fluid communication with the circulating oil inlet of the clarification tank, the heavy tar outlet of the clarification tank is in fluid communication with the fluid inlet of the heavy tar efflux pump, the fluid outlet of the heavy tar efflux pump is in fluid communication with the fluid inlet end of the heavy tar product collecting device; the circulating oil outlet of the clarification tank is in fluid communication with the circulating oil inlet of the lower circulating oil tower; the heat exchange medium inlet of the first heat exchanger of the quenching oil tower is in fluid communication with the fluid outlet of the heat exchange medium;

[0029] The side line fluid outlet of the upper circulating oil tower is in fluid communication with the circulating oil inlet of the upper circulating pump of the quenching oil tower, the circulating oil outlet of the upper circulating pump of the quenching oil tower is in fluid communication with the circulating oil inlet of the second heat exchanger of the quenching oil tower, the circulating oil first outlet of the second heat exchanger of the quenching oil tower is in fluid communication with the circulating oil inlet of the upper circulating oil tower, the circulating oil second outlet of the second heat exchanger of the quenching oil tower is in fluid communication with the fluid inlet end of the medium oil product collecting device; the heat exchange medium inlet of the second heat exchanger of the quenching oil tower is in fluid communication with the fluid outlet of the heat exchange medium;

[0030] In step (2), the ammonia washing purification module includes an ammonia washing tower, an ammonia water circulation tank, a circulating ammonia water elution pump and a circulating ammonia water cooler; the raw gas outlet of the upper circulating oil tower is fluidly connected to the raw gas inlet of the ammonia washing tower, and the raw gas outlet of the ammonia washing tower is fluidly connected to the raw gas inlet of the subsequent processing unit; in the ammonia washing tower, the raw gas and the circulating ammonia water flow directions are opposite;

[0031] The circulating ammonia water outlet of the ammonia scrubbing tower is in fluid communication with the circulating ammonia water inlet of the ammonia water circulation tank, the circulating ammonia water first outlet of the ammonia water circulation tank is in fluid communication with the circulating ammonia water inlet of the circulating ammonia water elution pump, the circulating ammonia water outlet of the circulating ammonia water elution pump is in fluid communication with the circulating ammonia water inlet of the circulating ammonia water cooler, and the circulating ammonia water outlet of the circulating ammonia water cooler is in fluid communication with the circulating ammonia water inlet of the ammonia scrubbing tower; the light oil outlet of the ammonia water circulation tank is in fluid communication with the fluid inlet end of the light oil product collecting device;

[0032] In step (3), the ammonia recovery module includes an ammonia still, an ammonia still raw material heat exchanger, an ammonia still top condenser, an ammonia buffer tank, an ammonia still reflux pump, an ammonia still feed pump, and an ammonia still bottom discharge pump; the second outlet of the circulating ammonia of the ammonia circulation tank is fluidly connected to the ammonia inlet of the ammonia still feed pump, the ammonia outlet of the ammonia still feed pump is fluidly connected to the ammonia inlet of the ammonia still raw material heat exchanger, and the ammonia outlet of the ammonia still raw material heat exchanger is fluidly connected to the ammonia inlet of the ammonia still. The ammonia vapor outlet of the ammonia still column is in fluid communication with the ammonia vapor inlet of the ammonia still column top condenser, the condensed fluid outlet of the ammonia still column top condenser is in fluid communication with the condensed fluid inlet of the ammonia aqueous buffer tank, the ammonia aqueous outlet of the ammonia aqueous buffer tank is in fluid communication with the ammonia aqueous inlet of the ammonia still column reflux pump, the circulating ammonia aqueous outlet of the ammonia still column reflux pump is in fluid communication with the circulating ammonia aqueous inlet of the ammonia still column, and the recovered ammonia aqueous outlet of the ammonia still column reflux pump is in fluid communication with the fluid inlet end of the ammonia aqueous collection device;

[0033] The ammonia evaporation wastewater outlet of the ammonia evaporation tower is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower raw material heat exchanger, the ammonia evaporation wastewater outlet of the ammonia evaporation tower raw material heat exchanger is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower bottom discharge pump, and the ammonia evaporation wastewater outlet of the ammonia evaporation tower bottom discharge pump is fluidly connected to the fluid inlet end of the ammonia evaporation wastewater biochemical system; the steam outlet of the first heat exchanger of the quenching oil tower is fluidly connected to the steam inlet of the ammonia evaporation tower, and the steam outlet of the second heat exchanger of the quenching oil tower is also fluidly connected to the steam inlet of the ammonia evaporation tower.

[0034] In the above-mentioned raw gas cooling and purification process, in step (1): the raw gas enters the lower circulating oil tower, and contacts the lower circulating oil in the lower circulating oil tower in countercurrent, performs heat exchange and separates gas, liquid and solid particles; the raw gas after being washed and cooled by the lower circulating oil continues to flow upward and enter the upper circulating oil tower; the lower circulating oil discharged from the lower circulating oil tower is discharged through the bottom transfer pump of the quenching oil tower to the first heat exchanger of the quenching oil tower for heat exchange with the heat exchange medium, and then enters the clarification tank; the heat absorbed from the lower circulating oil by the first heat exchanger of the quenching oil tower is used for distilling ammonia water in the ammonia distillation tower;

[0035] The solid particles and heavy tar carried in the lower circulating oil are deposited on the bottom of the clarifier tank, and are sent out of the system by the heavy tar effluent pump and the heavy tar product is collected. The oil in the upper part of the clarifier tank is used as the lower circulating oil and returned to the lower circulating oil tower through the lower circulating pump of the quenching oil tower to continue eluting and cooling the raw gas.

[0036] In the upper circulating oil tower, the raw gas and the upper circulating oil in the upper circulating oil tower are in countercurrent contact for heat exchange; the raw gas after heat exchange is discharged from the top of the upper circulating oil tower and enters the ammonia scrubber; the upper circulating oil is discharged through the side line of the upper circulating oil tower and pumped to the second heat exchanger of the quenching oil tower via the upper circulating pump of the quenching oil tower for heat exchange with the heat exchange medium. After heat exchange, the upper circulating oil is divided into two parts, one part is returned to the upper circulating oil tower for elution and cooling of the raw gas, and the other part is discharged from the system as a medium oil product; the heat absorbed from the upper circulating oil by the second heat exchanger of the quenching oil tower is used to distill ammonia water in the ammonia distillation tower;

[0037] In step (2): the raw gas enters from the lower inlet of the ammonia scrubber, contacts with the circulating ammonia water in countercurrent for heat exchange, and the raw gas after heat exchange and cooling is discharged from the top of the ammonia scrubber into the subsequent processing unit; the circulating ammonia water after heat exchange is discharged from the kettle of the ammonia scrubber into the ammonia water circulation tank; in the ammonia water circulation tank, light oil products are collected from the upper layer of the ammonia water circulation tank, and a part of the liquid phase in the lower layer of the ammonia water circulation tank is pumped as circulating ammonia water to the circulating ammonia water cooler for heat exchange through the circulating ammonia water elution pump, and the circulating ammonia water after heat exchange returns to the ammonia scrubber to circulate and elute the raw gas; another part of the liquid phase in the lower layer of the ammonia water circulation tank is pumped as residual ammonia water into the ammonia still tower raw material heat exchanger through the ammonia still tower feed pump for heat exchange and then enters the ammonia still tower;

[0038] In step (3), the residual ammonia water is treated by steam distillation; the ammonia-containing steam discharged from the top of the ammonia evaporation tower is cooled by the top condenser of the ammonia evaporation tower and then enters the ammonia water buffer tank; the ammonia water in the ammonia water buffer tank is partially refluxed to the top of the ammonia evaporation tower through the ammonia evaporation tower reflux pump, and the rest is discharged from the system as an ammonia water product; the ammonia evaporation wastewater discharged from the bottom of the ammonia evaporation tower enters the ammonia evaporation tower raw material heat exchanger to exchange heat with the residual ammonia water entering the ammonia evaporation tower, and is sent to the subsequent biochemical treatment system through the ammonia evaporation tower bottom discharge pump.

[0039] In the above-mentioned raw gas cooling and purification process, in step (1): the temperature of the raw gas is 500-800°C; the temperature of the lower circulating oil discharged from the kettle of the lower circulating oil tower is 260-320°C; the heat exchange medium of the first heat exchanger of the quenching oil tower is circulating condensed water, the temperature of the circulating condensed water is 134-250°C, and the absolute pressure is 0.3-3.0 MPa; the temperature of the lower circulating oil entering the clarifier is 180-250°C;

[0040] The temperature of the upper circulating oil discharged from the side line of the upper circulating oil tower is 130-160°C; the heat exchange medium of the second heat exchanger of the quenching oil tower is circulating condensed water, the temperature of the circulating condensed water is 112-135°C, and the absolute pressure is 0.15-0.3Mpa; the temperature of the medium oil product is 120-145°C;

[0041] The heat exchange medium of the first heat exchanger of the quenching oil tower generates medium-low pressure steam with a steam pressure of 0.3 to 3.0 MPa after heat exchange; the heat exchange medium of the second heat exchanger of the quenching oil tower generates low pressure steam with a steam pressure of 0.15 to 0.5 MPa after heat exchange; part of the medium-low pressure steam is used as the heating source of the ammonia still tower, and the other part is transported out of the system; all of the low pressure steam is used as the heating source of the ammonia still tower;

[0042] In step (2), the temperature of the raw gas entering the ammonia scrubber is 105-115°C; the temperature of the cooled raw gas discharged from the top of the ammonia scrubber is 50-80°C; the temperature of the circulating ammonia water discharged from the kettle of the ammonia scrubber is 65-85°C; the heat exchange medium of the circulating ammonia water cooler is circulating cooling water, and the temperature of the circulating cooling water is 25-35°C; the temperature of the light oil product is 65-85°C; the temperature of the residual ammonia water entering the ammonia still is 80-95°C;

[0043] In step (3), the temperature of the ammonia steam discharged from the top of the ammonia evaporation tower is 92-98° C., the temperature of the ammonia evaporation wastewater discharged from the bottom of the ammonia evaporation tower is 102-110° C.; and the concentration of the ammonia water in the ammonia water buffer tank is 12-20 wt%.

[0044] In the above-mentioned raw gas cooling and purification process, the heavy tar is a substance with a boiling point greater than 180°C and less than or equal to 300°C, including asphaltenes, anthracene, phenanthrene, carbazole, quinoline and xylenol; the medium oil product is a substance with a boiling point greater than 85°C and less than or equal to 180°C, including naphthalene, methylnaphthalene, indole, dimethylnaphthalene and phenol; the light oil product is a substance with a boiling point greater than 50 and less than or equal to 85°C, including benzene, toluene, xylene and pyridine.

[0045] The technical solution of the present invention achieves the following beneficial technical effects:

[0046] 1. The raw gas cooling and purification system and process of the present invention, by setting up two upper and lower circulating oil towers in the quenching oil tower, can not only recover most of the heat in the raw gas, but also effectively separate and recover the solid particles, heavy tar and medium oil in the raw gas; then the ammonia scrubber is used to further rinse and cool the raw gas discharged from the quenching oil tower, which can further recover the waste heat and entrained light oil in the raw gas; finally, the ammonia water recovered in the ammonia scrubber is treated in an ammonia evaporator to recover the ammonia water and improve the water quality of the remaining ammonia water, thereby reducing the difficulty of its biochemical treatment. In the raw gas cooling and purification process of the present invention, the steam consumed by the ammonia evaporator is entirely derived from the medium and low pressure steam recovered by the quenching oil tower, which not only realizes the effective recovery and utilization of the waste heat of the raw gas, greatly reduces the spray circulation volume of the circulating ammonia water and the amount of circulating cooling water, but also effectively separates and recovers the light, medium and heavy oil products in the raw gas during the cooling and purification process, and also significantly improves the water quality of the remaining ammonia water, thereby significantly reducing the difficulty of its treatment. This is of great significance for achieving long-term stable operation and energy saving and consumption reduction of the raw gas cooling and purification system.

[0047] 2. Compared with the existing raw gas cooling and purification process, the raw gas cooling and purification system of the present invention has the following advantages: it can effectively recover the waste heat of raw gas; greatly reduce the amount of circulating ammonia water, and the amount of circulating ammonia water is reduced by at least 50% compared with the existing process; greatly reduce the amount of system circulating condensed water, and the amount of circulating cooling water is reduced by at least 50% compared with the existing process; it can effectively improve the water quality of residual ammonia water, and the biodegradability of residual ammonia water (BOD / COD, i.e. B / C ratio) is increased by 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the raw gas cooling and purification system and process in Example 1 of the present invention.

[0049] The reference numerals in the figure are as follows: T01-quench oil tower; T02-ammonia washing tower; T03-ammonia still tower; E01-quench oil tower first heat exchanger; E02-quench oil tower second heat exchanger; E03-circulating ammonia water cooler; E04-ammonia still tower raw material heat exchanger; E05-ammonia still tower top condenser; E06-ammonia still tower reboiler; L01-clarifier; L02-ammonia water circulation tank; L03-ammonia water buffer tank; P01-quench oil tower bottom delivery pump; P02-quench oil tower lower section circulation pump; P03-heavy tar effluent pump; P04-quench oil tower upper section circulation pump; P05-circulating ammonia water elution pump; P06-ammonia still tower feed pump; P07-ammonia still tower reflux pump; P08-ammonia still tower bottom discharge pump. DETAILED DESCRIPTION

[0050] Example 1

[0051] like Figure 1 As shown, the raw gas cooling and purification system of this embodiment includes a cooling and purification module, an ammonia washing and purification module, and an ammonia water recovery module;

[0052] The cooling and purification module includes a quenching oil tower T01, a quenching oil tower bottom delivery pump P01, a quenching oil tower first heat exchanger E01, a clarifier L01, a quenching oil tower lower section circulation pump P02, a heavy tar effluent pump P03, a quenching oil tower upper section circulation pump P04, and a quenching oil tower second heat exchanger E02. The quenching oil tower T01 includes an upper section circulation oil tower and a lower section circulation oil tower. The raw gas outlet of the coke oven riser is fluidly connected to the raw gas inlet of the lower section circulation oil tower, and the raw gas outlet of the lower section circulation oil tower is fluidly connected to the raw gas inlet of the upper section circulation oil tower. In the quenching oil tower T01, the raw gas and circulating oil flow in opposite directions.

[0053] The circulating oil outlet of the lower circulating oil tower is in fluid communication with the circulating oil inlet of the bottom delivery pump P01 of the quenching oil tower, the circulating oil outlet of the bottom delivery pump P01 of the quenching oil tower is in fluid communication with the circulating oil inlet of the first heat exchanger E01 of the quenching oil tower, the circulating oil outlet of the first heat exchanger E01 of the quenching oil tower is in fluid communication with the circulating oil inlet of the clarification tank L01, the heavy tar outlet of the clarification tank L01 is in fluid communication with the fluid inlet of the heavy tar efflux pump P03, the fluid outlet of the heavy tar efflux pump P03 is in fluid communication with the fluid inlet end of the heavy tar product collection device; the circulating oil outlet of the clarification tank L01 is in fluid communication with the circulating oil inlet of the lower circulating oil tower; the heat exchange medium inlet of the first heat exchanger E01 of the quenching oil tower is in fluid communication with the fluid outlet of the heat exchange medium;

[0054] The sideline fluid outlet of the upper circulating oil tower is in fluid communication with the circulating oil inlet of the upper circulating pump P04 of the quenching oil tower, the circulating oil outlet of the upper circulating pump P04 of the quenching oil tower is in fluid communication with the circulating oil inlet of the second heat exchanger E02 of the quenching oil tower, the circulating oil first outlet of the second heat exchanger E02 of the quenching oil tower is in fluid communication with the circulating oil inlet of the upper circulating oil tower, the circulating oil second outlet of the second heat exchanger E02 of the quenching oil tower is in fluid communication with the fluid inlet end of the medium oil product collection device; the heat exchange medium inlet of the second heat exchanger E02 of the quenching oil tower is in fluid communication with the fluid outlet of the heat exchange medium;

[0055] The ammonia cleaning module includes an ammonia cleaning tower T02, an ammonia water circulation tank L02, a circulating ammonia water elution pump P05, and a circulating ammonia water cooler E03; the raw gas outlet of the upper circulating oil tower is fluidly connected to the raw gas inlet of the ammonia cleaning tower T02, and the raw gas outlet of the ammonia cleaning tower T02 is fluidly connected to the raw gas inlet of the subsequent treatment unit; in the ammonia cleaning tower, the raw gas and the circulating ammonia water flow in opposite directions;

[0056] The circulating ammonia water outlet of the ammonia scrubber T02 is in fluid communication with the circulating ammonia water inlet of the ammonia water circulation tank L02, the circulating ammonia water first outlet of the ammonia water circulation tank L02 is in fluid communication with the circulating ammonia water inlet of the circulating ammonia water elution pump P05, the circulating ammonia water outlet of the circulating ammonia water elution pump P05 is in fluid communication with the circulating ammonia water inlet of the circulating ammonia water cooler E03, and the circulating ammonia water outlet of the circulating ammonia water cooler E03 is in fluid communication with the circulating ammonia water inlet of the ammonia scrubber T02; the light oil outlet of the ammonia water circulation tank L02 is in fluid communication with the fluid inlet end of the light oil product collecting device;

[0057] The ammonia recovery module includes an ammonia still T03, an ammonia still raw material heat exchanger E04, an ammonia still top condenser E05, an ammonia buffer tank L03, an ammonia still reflux pump P07, an ammonia still feed pump P06, an ammonia still reboiler E06 and an ammonia still bottom discharge pump P08; the second outlet of the circulating ammonia water of the ammonia circulation tank L02 is fluidly connected to the ammonia water inlet of the ammonia still feed pump P06, the ammonia water outlet of the ammonia still feed pump P06 is fluidly connected to the ammonia water inlet of the ammonia still raw material heat exchanger E04, the ammonia water outlet of the ammonia still raw material heat exchanger E04 is fluidly connected to the ammonia water inlet of the ammonia still T03, and the ammonia still The ammonia vapor outlet of the ammonia tower T03 is fluidly connected to the ammonia vapor inlet of the ammonia still tower top condenser E05, the condensed fluid outlet of the ammonia still tower top condenser E05 is fluidly connected to the condensed fluid inlet of the ammonia solution buffer tank L03, the ammonia solution outlet of the ammonia solution buffer tank L03 is fluidly connected to the ammonia solution inlet of the ammonia still tower reflux pump P07, the circulating ammonia solution outlet of the ammonia still tower reflux pump P07 is fluidly connected to the circulating ammonia solution inlet of the ammonia still tower T03, and the recovered ammonia solution outlet of the ammonia still tower reflux pump P07 is fluidly connected to the fluid inlet end of the ammonia solution collecting device; the ammonia still tower reboiler E06 is used to heat the material in the ammonia still tower;

[0058] The ammonia evaporation wastewater outlet of the ammonia evaporation tower T03 is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower raw material heat exchanger E04, the ammonia evaporation wastewater outlet of the ammonia evaporation tower raw material heat exchanger E04 is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower bottom discharge pump P08, and the ammonia evaporation wastewater outlet of the ammonia evaporation tower bottom discharge pump P08 is fluidly connected to the fluid inlet end of the ammonia evaporation wastewater biochemical system; the steam outlet of the first heat exchanger E01 of the quenching oil tower is fluidly connected to the steam inlet of the ammonia evaporation tower T03, and the steam outlet of the second heat exchanger E02 of the quenching oil tower is also fluidly connected to the steam inlet of the ammonia evaporation tower T03.

[0059] Example 2

[0060] like Figure 1 As shown, the raw gas cooling and purification process of this embodiment adopts the raw gas cooling and purification system of Example 1 for purification and cooling, and includes the following steps:

[0061] Step (1), the raw gas (temperature of 500°C) from the coke oven riser enters the lower circulating oil tower, contacts with the lower circulating oil in the lower circulating oil tower in countercurrent, exchanges heat and separates gas, liquid and solid particles; the raw gas after being washed and cooled by the lower circulating oil continues to flow upward and enters the upper circulating oil tower; the lower circulating oil (temperature of 260°C) discharged from the lower circulating oil tower is discharged to the first heat exchanger E01 of the quenching oil tower through the bottom delivery pump P01 of the quenching oil tower to exchange heat with the heat exchange medium (low-pressure condensate with a pressure of 0.3 MPa and a temperature of 134°C), and the temperature is reduced to 180°C after the heat exchange, and then enters the clarification tank L01, and the low-pressure condensate after heat exchange is prepared into 0.3 MPa low-pressure steam for distilling ammonia water in the ammonia distillation tower T03;

[0062] The solid particles and heavy tar carried in the lower circulating oil are deposited on the bottom of the clarifier L01 and are sent out of the system by the heavy tar effluent pump P03 to collect the heavy tar product. The oil in the upper part of the clarifier L01 is used as the lower circulating oil and returned to the lower circulating oil tower through the lower circulating pump P02 of the quenching oil tower to continue eluting and cooling the raw gas.

[0063] In the upper circulating oil tower, the raw gas is in countercurrent contact with the upper circulating oil in the upper circulating oil tower for heat exchange; the raw gas after heat exchange (temperature dropped to 105°C) is discharged from the top of the upper circulating oil tower and enters the ammonia washing tower T02; the upper circulating oil after heat exchange (temperature increased to 130°C) is discharged through the side line of the upper circulating oil tower and pumped to the second heat exchanger E02 of the quenching oil tower through the upper circulating pump P04 of the quenching oil tower for heat exchange with the heat exchange medium (low-pressure condensate with a pressure of 0.15Mpa and a temperature of 112°C). The upper circulating oil after heat exchange (temperature dropped to 120°C) is divided into two parts, one part returns to the upper circulating oil tower to rinse and cool the raw gas, and the other part is discharged from the system as a medium oil product; the low-pressure condensate after heat exchange is prepared into 0.15Mpa low-pressure steam for distilling ammonia water in the ammonia distillation tower T03

[0064] Step (2), the raw gas enters from the lower inlet of the ammonia scrubber T02, contacts with the circulating ammonia water in countercurrent for heat exchange, and the raw gas after heat exchange cooling (the temperature drops to 50°C) is discharged from the top of the ammonia scrubber T02 and enters the subsequent treatment unit; the circulating ammonia water after heat exchange (the temperature rises to 65°C) is discharged from the bottom of the ammonia scrubber T02 into the ammonia water circulation tank L02; in the ammonia water circulation tank L02, the light oil product is collected from the upper layer of the ammonia water circulation tank L02, and the temperature of the light oil product is 65°C; the ammonia water circulation tank L0 A portion of the liquid phase in the lower layer is pumped as circulating ammonia water through the circulating ammonia water elution pump P05 to the circulating ammonia water cooler E03 for heat exchange. The heat exchange medium is circulating cooling water at a temperature of 25°C. After heat exchange, the temperature of the circulating ammonia water drops to 35°C and returns to the ammonia scrubber T02 for circulating elution of the raw coal gas. Another portion of the liquid phase in the lower layer of the ammonia water circulation tank L02 is fed as residual ammonia water through the ammonia still feed pump P06 to the ammonia still feed heat exchanger E04. After heat exchange with the ammonia still wastewater, the temperature is raised to 80°C and enters the ammonia still T03.

[0065] Step (3) treating the remaining ammonia water by steam distillation; the ammonia-containing steam (temperature of 92° C.) discharged from the top of the ammonia evaporation tower T03 is cooled to 40° C. by the ammonia evaporation tower top condenser E05 and then enters the ammonia water buffer tank L03, wherein the concentration of ammonia water in the ammonia water buffer tank L03 is 12 wt %. A portion of the ammonia water in the ammonia water buffer tank L03 is refluxed to the top of the ammonia evaporation tower T03 through the ammonia evaporation tower reflux pump P07, and a portion is discharged from the system as an ammonia water product; the ammonia evaporation wastewater (temperature of 102° C.) discharged from the bottom of the ammonia evaporation tower T03 enters the ammonia evaporation tower raw material heat exchanger E04 and is heat-exchanged with the remaining ammonia water entering the ammonia evaporation tower T03, and the heat exchange temperature is reduced to 85° C., and the wastewater is sent to the subsequent biochemical treatment system through the ammonia evaporation tower bottom discharge pump P08.

[0066] In this embodiment, the composition of the raw gas includes: H2, CH4, CO, CO2, other hydrocarbons, and water vapor; the main components of the collected heavy tar are asphaltene, anthracene, phenanthrene, quinoline and xylenol, the main components of the medium oil product are naphthalene, methylnaphthalene and phenol, and the main components of the light oil product are benzene, toluene, xylene and pyridine.

[0067] For the convenience of comparison between Example 2 and the conventional circulating ammonia water direct cooling of raw gas cooling purification process, the process of treating 1000000m 3 Taking raw coal gas as an example, the specific indicators under the two processes are compared. The comparative data are shown in Table 1:

[0068] Table 1

[0069]

[0070] Example 3

[0071] The raw gas cooling and purification process of this embodiment includes the following steps:

[0072] Step (1), the raw gas (temperature of 800°C) from the coke oven riser enters the lower circulating oil tower, contacts with the lower circulating oil in the lower circulating oil tower in countercurrent, exchanges heat and separates gas, liquid and solid particles; the raw gas after being washed and cooled by the lower circulating oil continues to flow upward and enters the upper circulating oil tower; the lower circulating oil (temperature of 320°C) discharged from the lower circulating oil tower is discharged to the first heat exchanger E01 of the quenching oil tower through the bottom delivery pump P01 of the quenching oil tower to exchange heat with the heat exchange medium (low-pressure condensate with a pressure of 3.0 MPa and a temperature of 235°C), and the temperature is reduced to 250°C after the heat exchange, and then enters the clarification tank L01, and the low-pressure condensate after heat exchange is prepared into 3.0 MPa low-pressure steam for distilling ammonia water in the ammonia distillation tower T03;

[0073] The solid particles and heavy tar carried in the lower circulating oil are deposited on the bottom of the clarifier L01 and are sent out of the system by the heavy tar effluent pump P03 to collect the heavy tar product. The oil in the upper part of the clarifier L01 is used as the lower circulating oil and returned to the lower circulating oil tower through the lower circulating pump P02 of the quenching oil tower to continue eluting and cooling the raw gas.

[0074] In the upper circulating oil tower, the raw gas is in countercurrent contact with the upper circulating oil in the upper circulating oil tower for heat exchange; the raw gas after heat exchange (temperature dropped to 115°C) is discharged from the top of the upper circulating oil tower and enters the ammonia washing tower T02; the upper circulating oil after heat exchange (temperature increased to 160°C) is discharged through the side line of the upper circulating oil tower and pumped to the second heat exchanger E02 of the quenching oil tower through the upper circulating pump P04 of the quenching oil tower for heat exchange with the heat exchange medium (low-pressure condensate with a pressure of 0.3Mpa and a temperature of 134°C). The upper circulating oil after heat exchange (temperature dropped to 145°C) is divided into two parts, one part returns to the upper circulating oil tower to rinse and cool the raw gas, and the other part is discharged from the system as a medium oil product; the low-pressure condensate after heat exchange is prepared into 0.3Mpa low-pressure steam for distilling ammonia water in the ammonia distillation tower T03

[0075] In step (2), the raw gas enters from the lower inlet of the ammonia scrubber T02, and is countercurrently contacted with the circulating ammonia water for heat exchange. The raw gas after heat exchange cooling (the temperature drops to 80°C) is discharged from the top of the ammonia scrubber T02 and enters the subsequent treatment unit; the circulating ammonia water after heat exchange (the temperature rises to 85°C) is discharged from the bottom of the ammonia scrubber T02 into the ammonia water circulation tank L02; in the ammonia water circulation tank L02, the light oil product is collected from the upper layer of the ammonia water circulation tank L02, and the temperature of the light oil product is 85°C; the ammonia water circulation tank L0 A portion of the liquid phase in the lower layer is pumped as circulating ammonia water through the circulating ammonia water elution pump P05 to the circulating ammonia water cooler E03 for heat exchange. The heat exchange medium is circulating cooling water at a temperature of 35°C. After heat exchange, the temperature of the circulating ammonia water drops to 50°C. The circulating ammonia water returns to the ammonia scrubber T02 to circulate and elute the raw coal gas. Another portion of the liquid phase in the lower layer of the ammonia water circulation tank L02 is sent as residual ammonia water through the ammonia still feed pump P06 to the ammonia still feed heat exchanger E04. After heat exchange with the ammonia still wastewater, the temperature is raised to 95°C and enters the ammonia still T03.

[0076] Step (3) treating the remaining ammonia water by steam distillation; the ammonia-containing steam (temperature of 98° C.) discharged from the top of the ammonia evaporation tower T03 is cooled to 40° C. by the ammonia evaporation tower top condenser E05 and then enters the ammonia water buffer tank L03, wherein the concentration of ammonia water in the ammonia water buffer tank L03 is 20wt%. A portion of the ammonia water in the ammonia water buffer tank L03 is refluxed to the top of the ammonia evaporation tower T03 through the ammonia evaporation tower reflux pump P07, and a portion is discharged from the system as an ammonia water product; the ammonia evaporation wastewater (temperature of 110° C.) discharged from the bottom of the ammonia evaporation tower T03 enters the ammonia evaporation tower raw material heat exchanger E04 for heat exchange with the remaining ammonia water entering the ammonia evaporation tower T03 (temperature reduced to 98° C.), and is sent to the subsequent biochemical treatment system through the ammonia evaporation tower bottom discharge pump P08.

[0077] In this embodiment, the composition of the raw gas includes: H2, CH4, CO, CO2, other hydrocarbons, and water vapor; the main components of the collected heavy tar are asphaltene, anthracene and phenanthrene, the main components of the medium oil product are naphthalene, methylnaphthalene, phenol, quinoline and xylenol, and the main components of the light oil product are benzene, toluene, xylene and pyridine.

[0078] For the convenience of comparison between Example 3 and the conventional circulating ammonia water direct cooling raw gas cooling purification process, the process of treating 1000000m 3 Taking raw coal gas as an example, the specific indicators under the two processes are compared. The comparative data are shown in Table 2:

[0079] Table 2

[0080]

[0081]

[0082] As can be seen from the data in Tables 1 and 2, when treating the same volume of raw gas as in Examples 2 and 3, the conventional raw gas cooling and purification process using direct cooling with circulating ammonia water not only fails to recover waste heat from the raw gas, but also results in a lower oil product recovery rate and lower quality of the recovered oil product. Furthermore, it requires a greater amount of circulating ammonia water and consumes more circulating cooling water. Furthermore, the residual ammonia water treatment step requires additional low-pressure steam, resulting in a poorer biodegradability of the resulting residual ammonia water. This demonstrates that the raw gas cooling and purification process of the present invention offers significant advantages over conventional processes.

[0083] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the claims of this patent application.

Claims

1. A raw gas cooling and purification system, characterized in that: It includes a cooling and purification module, an ammonia washing and purification module, and an ammonia water recovery module; the raw gas outlet of the cooling and purification module is fluidly connected to the raw gas inlet of the ammonia washing and purification module, the steam outlet of the cooling and purification module is fluidly connected to the steam inlet of the ammonia water recovery module; the ammonia water outlet of the ammonia washing and purification module is fluidly connected to the ammonia water inlet of the ammonia water recovery module; In the cooling and purification module, heavy tar and medium oil in the raw gas are separated and collected, and the raw gas discharged from the cooling and purification module enters the ammonia washing purification module, and the steam generated by the cooling and purification module enters the ammonia water recovery module for reuse; after being processed by the ammonia washing purification module, the light oil in the raw gas is separated and collected, and the raw gas discharged from the ammonia washing purification module enters the subsequent processing unit, and the ammonia water discharged from the ammonia washing purification module enters the ammonia water recovery module for distillation recovery treatment.

2. The raw gas cooling and purification system according to claim 1, characterized in that: The cooling and purification module includes a quenching oil tower (T01), a quenching oil tower bottom delivery pump (P01), a quenching oil tower first heat exchanger (E01), a clarifier (L01), a quenching oil tower lower section circulation pump (P02), a heavy tar effluent pump (P03), a quenching oil tower upper section circulation pump (P04) and a quenching oil tower second heat exchanger (E02); The quenching oil tower (T01) includes an upper circulating oil tower and a lower circulating oil tower; the raw gas outlet of the coke oven riser is fluidly connected to the raw gas inlet of the lower circulating oil tower, the raw gas outlet of the lower circulating oil tower is fluidly connected to the raw gas inlet of the upper circulating oil tower, and the raw gas outlet of the upper circulating oil tower is fluidly connected to the raw gas inlet of the ammonia washing purification module; in the quenching oil tower (T01), the raw gas and circulating oil flow in opposite directions; The circulating oil outlet of the lower circulating oil tower is fluidly connected to the circulating oil inlet of the bottom delivery pump (P01) of the quenching oil tower, the circulating oil outlet of the bottom delivery pump (P01) of the quenching oil tower is fluidly connected to the circulating oil inlet of the first heat exchanger (E01) of the quenching oil tower, the circulating oil outlet of the first heat exchanger (E01) of the quenching oil tower is fluidly connected to the circulating oil inlet of the clarification tank (L01), the heavy tar outlet of the clarification tank (L01) is fluidly connected to the heavy tar effluent pump (P 03), the fluid inlet of the heavy tar effluent pump (P03) is fluidly connected to the fluid inlet end of the heavy tar product collection device; the circulating oil outlet of the clarification tank (L01) is fluidly connected to the circulating oil inlet of the lower circulating oil tower; the heat exchange medium inlet of the first heat exchanger (E01) of the quenching oil tower is fluidly connected to the fluid outlet of the heat exchange medium, and the steam outlet of the first heat exchanger (E01) of the quenching oil tower is fluidly connected to the steam inlet of the ammonia recovery module; The side line fluid outlet of the upper circulating oil tower is fluidly connected to the circulating oil inlet of the upper circulating pump (P04) of the quenching oil tower, the circulating oil outlet of the upper circulating pump (P04) of the quenching oil tower is fluidly connected to the circulating oil inlet of the second heat exchanger (E02) of the quenching oil tower, the first circulating oil outlet of the second heat exchanger (E02) of the quenching oil tower is fluidly connected to the circulating oil inlet of the upper circulating oil tower, the second circulating oil outlet of the second heat exchanger (E02) of the quenching oil tower is fluidly connected to the fluid inlet end of the petroleum product collection device; the heat exchange medium inlet of the second heat exchanger (E02) of the quenching oil tower is fluidly connected to the fluid outlet of the heat exchange medium, and the steam outlet of the second heat exchanger (E02) of the quenching oil tower is fluidly connected to the steam inlet of the ammonia recovery module.

3. The raw gas cooling and purification system according to claim 1, characterized in that: The ammonia washing and purification module includes an ammonia washing tower (T02), an ammonia water circulation tank (L02), a circulating ammonia water washing pump (P05) and a circulating ammonia water cooler (E03); the raw gas outlet of the cooling and purification module is fluidically connected to the raw gas inlet of the ammonia washing tower (T02), and the raw gas outlet of the ammonia washing tower (T02) is fluidically connected to the raw gas inlet of the subsequent treatment unit; in the ammonia washing tower, the raw gas and the circulating ammonia water flow in opposite directions; The circulating ammonia water outlet of the ammonia washing tower (T02) is fluidly connected to the circulating ammonia water inlet of the ammonia water circulation tank (L02); the circulating ammonia water first outlet of the ammonia water circulation tank (L02) is fluidly connected to the circulating ammonia water inlet of the circulating ammonia water elution pump (P05); the circulating ammonia water outlet of the circulating ammonia water elution pump (P05) is fluidly connected to the circulating ammonia water inlet of the circulating ammonia water cooler (E03); the circulating ammonia water outlet of the circulating ammonia water cooler (E03) is fluidly connected to the circulating ammonia water inlet of the ammonia washing tower (T02); the circulating ammonia water second outlet of the ammonia water circulation tank (L02) is fluidly connected to the ammonia water inlet end of the ammonia water recovery module; the light oil outlet of the ammonia water circulation tank (L02) is fluidly connected to the fluid inlet end of the light oil product collection device.

4. The raw gas cooling and purification system according to claim 1, characterized in that: The ammonia recovery module includes an ammonia still (T03), an ammonia still raw material heat exchanger (E04), an ammonia still top condenser (E05), an ammonia buffer tank (L03), an ammonia still reflux pump (P07), an ammonia still feed pump (P06) and an ammonia still bottom discharge pump (P08); the ammonia outlet of the ammonia washing purification module is fluidly connected to the ammonia inlet of the ammonia still feed pump (P06), the ammonia outlet of the ammonia still feed pump (P06) is fluidly connected to the ammonia inlet of the ammonia still raw material heat exchanger (E04), and the ammonia outlet of the ammonia still raw material heat exchanger (E04) is fluidly connected to the ammonia inlet of the ammonia still (T03). The ammonia vapor outlet of the ammonia evaporation tower (T03) is in fluid communication with the ammonia vapor inlet of the ammonia evaporation tower top condenser (E05), the condensed fluid outlet of the ammonia evaporation tower top condenser (E05) is in fluid communication with the condensed fluid inlet of the ammonia aqueous buffer tank (L03), the ammonia aqueous outlet of the ammonia aqueous buffer tank (L03) is in fluid communication with the ammonia aqueous inlet of the ammonia evaporation tower reflux pump (P07), the circulating ammonia aqueous outlet of the ammonia evaporation tower reflux pump (P07) is in fluid communication with the circulating ammonia aqueous inlet of the ammonia evaporation tower (T03), and the recovered ammonia aqueous outlet of the ammonia evaporation tower reflux pump (P07) is in fluid communication with the fluid inlet end of the ammonia aqueous collection device; The ammonia evaporation wastewater outlet of the ammonia evaporation tower (T03) is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower raw material heat exchanger (E04), the ammonia evaporation wastewater outlet of the ammonia evaporation tower raw material heat exchanger (E04) is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower bottom discharge pump (P08), the ammonia evaporation wastewater outlet of the ammonia evaporation tower bottom discharge pump (P08) is fluidly connected to the fluid inlet end of the ammonia evaporation wastewater debiochemical system; the steam outlet end of the cooling and purification module is fluidly connected to the steam inlet end of the ammonia evaporation tower (T03).

5. The raw gas cooling and purification system according to claim 2, characterized in that: The ammonia washing purification module includes an ammonia washing tower (T02), an ammonia water circulation tank (L02), a circulating ammonia water elution pump (P05) and a circulating ammonia water cooler (E03); the raw gas outlet of the upper circulating oil tower is fluidly connected to the raw gas inlet of the ammonia washing tower (T02), and the raw gas outlet of the ammonia washing tower (T02) is fluidly connected to the raw gas inlet of the subsequent treatment unit; in the ammonia washing tower, the raw gas and the circulating ammonia water flow in opposite directions; The circulating ammonia water outlet of the ammonia scrubbing tower (T02) is in fluid communication with the circulating ammonia water inlet of the ammonia water circulation tank (L02); the circulating ammonia water first outlet of the ammonia water circulation tank (L02) is in fluid communication with the circulating ammonia water inlet of the circulating ammonia water elution pump (P05); the circulating ammonia water outlet of the circulating ammonia water elution pump (P05) is in fluid communication with the circulating ammonia water inlet of the circulating ammonia water cooler (E03); the circulating ammonia water outlet of the circulating ammonia water cooler (E03) is in fluid communication with the circulating ammonia water inlet of the ammonia scrubbing tower (T02); the light oil outlet of the ammonia water circulation tank (L02) is in fluid communication with the fluid inlet end of the light oil product collecting device; The ammonia recovery module includes an ammonia still (T03), an ammonia still raw material heat exchanger (E04), an ammonia still top condenser (E05), an ammonia buffer tank (L03), an ammonia still reflux pump (P07), an ammonia still feed pump (P06) and an ammonia still bottom discharge pump (P08); the second outlet of the circulating ammonia of the ammonia circulation tank (L02) is fluidically connected to the ammonia inlet of the ammonia still feed pump (P06), the ammonia outlet of the ammonia still feed pump (P06) is fluidically connected to the ammonia inlet of the ammonia still raw material heat exchanger (E04), and the ammonia outlet of the ammonia still raw material heat exchanger (E04) is fluidically connected to the ammonia inlet of the ammonia still (T03). the ammonia vapor outlet of the ammonia evaporation tower (T03) is in fluid communication with the ammonia vapor inlet of the ammonia evaporation tower top condenser (E05), the condensed fluid outlet of the ammonia evaporation tower top condenser (E05) is in fluid communication with the condensed fluid inlet of the ammonia aqueous buffer tank (L03), the ammonia aqueous outlet of the ammonia aqueous buffer tank (L03) is in fluid communication with the ammonia aqueous inlet of the ammonia evaporation tower reflux pump (P07), the circulating ammonia aqueous outlet of the ammonia evaporation tower reflux pump (P07) is in fluid communication with the circulating ammonia aqueous inlet of the ammonia evaporation tower (T03), and the recovered ammonia aqueous outlet of the ammonia evaporation tower reflux pump (P07) is in fluid communication with the fluid inlet end of the ammonia aqueous collection device; The ammonia evaporation wastewater outlet of the ammonia evaporation tower (T03) is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower raw material heat exchanger (E04), the ammonia evaporation wastewater outlet of the ammonia evaporation tower raw material heat exchanger (E04) is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower bottom discharge pump (P08), and the ammonia evaporation wastewater outlet of the ammonia evaporation tower bottom discharge pump (P08) is fluidly connected to the fluid inlet end of the ammonia evaporation wastewater biochemical system; the steam outlet of the first heat exchanger (E01) of the quench oil tower is fluidly connected to the steam inlet of the ammonia evaporation tower (T03), and the steam outlet of the second heat exchanger (E02) of the quench oil tower is also fluidly connected to the steam inlet of the ammonia evaporation tower (T03).

6. A process for cooling and purifying raw coal gas, characterized in that: The raw gas cooling and purification system according to claim 1 is used to cool and purify the raw gas, comprising the following steps: Step (1), using the cooling and purification module to cool the raw gas and separate solid particles, liquid and gas in the raw gas to obtain heavy tar products, medium oil products and preliminarily cooled and purified raw gas; steam obtained by heat exchange with the raw gas is used for ammonia distillation in the ammonia recovery module; Step (2), using the ammonia washing purification module to perform circulating ammonia washing on the preliminarily cooled and purified raw gas, the preliminarily cooled and purified raw gas is washed with circulating ammonia water to obtain purified raw gas, the circulating ammonia water collected after washing is treated and separated to obtain a light oil product, a portion of the circulating ammonia water from which the light oil is removed is used for circulating ammonia washing of the raw gas, and a portion enters the ammonia water recovery module to distill and recover ammonia water; Step (3): utilizing the ammonia recovery module to distill and recover the ammonia, and the ammonia wastewater enters the biochemical system for biochemical treatment.

7. The raw gas cooling and purification process according to claim 6, characterized in that: In step (1), the cooling and purification module includes a quenching oil tower (T01), a quenching oil tower bottom delivery pump (P01), a quenching oil tower first heat exchanger (E01), a clarifier (L01), a quenching oil tower lower section circulation pump (P02), a heavy tar effluent pump (P03), a quenching oil tower upper section circulation pump (P04) and a quenching oil tower second heat exchanger (E02); The quenching oil tower (T01) includes an upper circulating oil tower and a lower circulating oil tower; the raw gas outlet of the coke oven riser is fluidly connected to the raw gas inlet of the lower circulating oil tower, and the raw gas outlet of the lower circulating oil tower is fluidly connected to the raw gas inlet of the upper circulating oil tower; in the quenching oil tower (T01), the raw gas and circulating oil flow in opposite directions; The circulating oil outlet of the lower circulating oil tower is in fluid communication with the circulating oil inlet of the bottom delivery pump (P01) of the quenching oil tower, the circulating oil outlet of the bottom delivery pump (P01) of the quenching oil tower is in fluid communication with the circulating oil inlet of the first heat exchanger (E01) of the quenching oil tower, the circulating oil outlet of the first heat exchanger (E01) of the quenching oil tower is in fluid communication with the circulating oil inlet of the clarification tank (L01), the heavy tar outlet of the clarification tank (L01) is in fluid communication with the fluid inlet of the heavy tar effluent pump (P03), the fluid outlet of the heavy tar effluent pump (P03) is in fluid communication with the fluid inlet end of the heavy tar product collecting device; the circulating oil outlet of the clarification tank (L01) is in fluid communication with the circulating oil inlet of the lower circulating oil tower; the heat exchange medium inlet of the first heat exchanger (E01) of the quenching oil tower is in fluid communication with the fluid outlet of the heat exchange medium; The sideline fluid outlet of the upper circulating oil tower is in fluid communication with the circulating oil inlet of the upper circulating pump (P04) of the quenching oil tower, the circulating oil outlet of the upper circulating pump (P04) of the quenching oil tower is in fluid communication with the circulating oil inlet of the second heat exchanger (E02) of the quenching oil tower, the first circulating oil outlet of the second heat exchanger (E02) of the quenching oil tower is in fluid communication with the circulating oil inlet of the upper circulating oil tower, the second circulating oil outlet of the second heat exchanger (E02) of the quenching oil tower is in fluid communication with the fluid inlet end of the medium oil product collecting device; the heat exchange medium inlet of the second heat exchanger (E02) of the quenching oil tower is in fluid communication with the fluid outlet of the heat exchange medium; In step (2), the ammonia washing purification module includes an ammonia washing tower (T02), an ammonia water circulation tank (L02), a circulating ammonia water elution pump (P05) and a circulating ammonia water cooler (E03); the raw gas outlet of the upper circulating oil tower is fluidly connected to the raw gas inlet of the ammonia washing tower (T02), and the raw gas outlet of the ammonia washing tower (T02) is fluidly connected to the raw gas inlet of the subsequent processing unit; in the ammonia washing tower, the raw gas and the circulating ammonia water flow in opposite directions; The circulating ammonia water outlet of the ammonia scrubbing tower (T02) is in fluid communication with the circulating ammonia water inlet of the ammonia water circulation tank (L02); the circulating ammonia water first outlet of the ammonia water circulation tank (L02) is in fluid communication with the circulating ammonia water inlet of the circulating ammonia water elution pump (P05); the circulating ammonia water outlet of the circulating ammonia water elution pump (P05) is in fluid communication with the circulating ammonia water inlet of the circulating ammonia water cooler (E03); the circulating ammonia water outlet of the circulating ammonia water cooler (E03) is in fluid communication with the circulating ammonia water inlet of the ammonia scrubbing tower (T02); the light oil outlet of the ammonia water circulation tank (L02) is in fluid communication with the fluid inlet end of the light oil product collecting device; In step (3), the ammonia recovery module includes an ammonia still (T03), an ammonia still raw material heat exchanger (E04), an ammonia still top condenser (E05), an ammonia buffer tank (L03), an ammonia still reflux pump (P07), an ammonia still feed pump (P06) and an ammonia still bottom discharge pump (P08) of the ammonia still; the circulating ammonia second outlet of the ammonia circulation tank (L02) is fluidly connected to the ammonia inlet of the ammonia still feed pump (P06), the ammonia outlet of the ammonia still feed pump (P06) is fluidly connected to the ammonia inlet of the ammonia still raw material heat exchanger (E04), and the ammonia outlet of the ammonia still raw material heat exchanger (E04) is fluidly connected to the ammonia still (T03). The ammonia inlet of the ammonia evaporation tower (T03) is fluidly connected, the ammonia vapor outlet of the ammonia evaporation tower (T03) is fluidly connected to the ammonia vapor inlet of the ammonia evaporation tower top condenser (E05), the condensed fluid outlet of the ammonia evaporation tower top condenser (E05) is fluidly connected to the condensed fluid inlet of the ammonia buffer tank (L03), the ammonia outlet of the ammonia buffer tank (L03) is fluidly connected to the ammonia inlet of the ammonia evaporation tower reflux pump (P07), the circulating ammonia outlet of the ammonia evaporation tower reflux pump (P07) is fluidly connected to the circulating ammonia inlet of the ammonia evaporation tower (T03), and the recovered ammonia outlet of the ammonia evaporation tower reflux pump (P07) is fluidly connected to the fluid inlet end of the ammonia collection device; The ammonia evaporation wastewater outlet of the ammonia evaporation tower (T03) is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower raw material heat exchanger (E04), the ammonia evaporation wastewater outlet of the ammonia evaporation tower raw material heat exchanger (E04) is fluidly connected to the ammonia evaporation wastewater inlet of the ammonia evaporation tower bottom discharge pump (P08), and the ammonia evaporation wastewater outlet of the ammonia evaporation tower bottom discharge pump (P08) is fluidly connected to the fluid inlet end of the ammonia evaporation wastewater biochemical system; the steam outlet of the first heat exchanger (E01) of the quench oil tower is fluidly connected to the steam inlet of the ammonia evaporation tower (T03), and the steam outlet of the second heat exchanger (E02) of the quench oil tower is also fluidly connected to the steam inlet of the ammonia evaporation tower (T03).

8. The raw gas cooling and purification process according to claim 7, characterized in that: In step (1): the raw gas enters the lower circulating oil tower, and contacts the lower circulating oil in the lower circulating oil tower in countercurrent, performs heat exchange and separates gas, liquid and solid particles; the raw gas after being washed and cooled by the lower circulating oil continues to flow upward and enter the upper circulating oil tower; the lower circulating oil discharged from the lower circulating oil tower is discharged into the first heat exchanger (E01) of the quenching oil tower through the bottom delivery pump (P01) of the quenching oil tower to exchange heat with the heat exchange medium, and then enters the clarification tank (L01); the heat absorbed from the lower circulating oil by the first heat exchanger (E01) of the quenching oil tower is used to distill ammonia water in the ammonia distillation tower (T03); Solid particles and heavy tar entrained in the lower circulating oil are deposited on the bottom of the clarifier (L01), and are sent out of the system via the heavy tar effluent pump (P03) and the heavy tar product is collected. The oil product in the upper part of the clarifier (L01) is used as the lower circulating oil and is returned to the lower circulating oil tower via the lower circulating pump (P02) of the quenching oil tower to continue eluting and cooling the raw coal gas. In the upper circulating oil tower, the raw gas and the upper circulating oil in the upper circulating oil tower are in countercurrent contact for heat exchange; the raw gas after heat exchange is discharged from the top of the upper circulating oil tower and enters the ammonia scrubber (T02); the upper circulating oil is discharged through the side line of the upper circulating oil tower and pumped to the second heat exchanger (E02) of the quenching oil tower via the upper circulating pump (P04) of the quenching oil tower for heat exchange with the heat exchange medium. After heat exchange, the upper circulating oil is divided into two parts, one part is returned to the upper circulating oil tower to rinse and cool the raw gas, and the other part is discharged as a medium oil product system; the heat absorbed from the upper circulating oil by the second heat exchanger (E02) of the quenching oil tower is used to distill ammonia water in the ammonia distillation tower (T03); In step (2): the raw gas enters from the lower inlet of the ammonia scrubber (T02), contacts with the circulating ammonia water in countercurrent for heat exchange, and the raw gas after heat exchange and cooling is discharged from the top of the ammonia scrubber (T02) and enters the subsequent treatment unit; the circulating ammonia water after heat exchange is discharged from the bottom of the ammonia scrubber (T02) into the ammonia water circulation tank (L02); in the ammonia water circulation tank (L02), the light oil product is collected from the upper layer of the ammonia water circulation tank (L02), and the ammonia water circulation tank (L02) is used to collect the light oil product. A portion of the liquid phase in the lower layer of the annular tank (L02) is pumped as circulating ammonia water through the circulating ammonia water elution pump (P05) to the circulating ammonia water cooler (E03) for heat exchange. After heat exchange, the circulating ammonia water returns to the ammonia scrubbing tower (T02) to circulate and elute the raw coal gas; another portion of the liquid phase in the lower layer of the ammonia water circulation tank (L02) is pumped as residual ammonia water through the ammonia still feed pump (P06) to the ammonia still feed heat exchanger (E04) for heat exchange before entering the ammonia still (T03). In step (3), the remaining ammonia water is treated by steam distillation; the ammonia-containing steam discharged from the top of the ammonia evaporation tower (T03) is cooled by the ammonia evaporation tower top condenser (E05) and then enters the ammonia water buffer tank (L03); a portion of the ammonia water in the ammonia water buffer tank (L03) is refluxed to the top of the ammonia evaporation tower (T03) through the ammonia evaporation tower reflux pump (P07), and a portion is discharged from the system as an ammonia water product; the ammonia evaporation wastewater discharged from the bottom of the ammonia evaporation tower (T03) enters the ammonia evaporation tower raw material heat exchanger (E04) to exchange heat with the remaining ammonia water entering the ammonia evaporation tower (T03), and is sent to the subsequent biochemical treatment system through the ammonia evaporation tower bottom discharge pump (P08).

9. The raw gas cooling and purification process according to claim 8, characterized in that: In step (1), the temperature of the raw gas is 500-800°C; the temperature of the lower circulating oil discharged from the kettle of the lower circulating oil tower is 260-320°C; the heat exchange medium of the first heat exchanger (E01) of the quenching oil tower is circulating condensed water, the temperature of the circulating condensed water is 134-250°C, and the absolute pressure is 0.3-3.0 MPa; the temperature of the lower circulating oil entering the clarifier (L01) is 180-250°C; The temperature of the upper circulating oil discharged from the side line of the upper circulating oil tower is 130-160°C; the heat exchange medium of the second heat exchanger (E02) of the quenching oil tower is circulating condensed water, the temperature of the circulating condensed water is 112-135°C, and the absolute pressure is 0.15-0.3Mpa; the temperature of the intermediate oil product is 120-145°C; The heat exchange medium of the first heat exchanger (E01) of the quenching oil tower generates medium-low pressure steam with a steam pressure of 0.3 to 3.0 MPa after heat exchange; the heat exchange medium of the second heat exchanger (E02) of the quenching oil tower generates low pressure steam with a steam pressure of 0.15 to 0.5 MPa after heat exchange; part of the medium-low pressure steam is used as a heating source for the ammonia still (T03), and the other part is transported out of the system; all of the low pressure steam is used as a heating source for the ammonia still (T03); In step (2), the temperature of the raw gas entering the ammonia scrubber (T02) is 105-115°C; the temperature of the cooled raw gas discharged from the top of the ammonia scrubber (T02) is 50-80°C; the temperature of the circulating ammonia water discharged from the bottom of the ammonia scrubber (T02) is 65-85°C; the heat exchange medium of the circulating ammonia water cooler (E03) is circulating cooling water, and the temperature of the circulating cooling water is 25-35°C; the temperature of the light oil product is 65-85°C; the temperature of the residual ammonia water entering the ammonia distillation tower (T03) is 80-95°C; In step (3), the temperature of the ammonia steam discharged from the top of the ammonia evaporation tower (T03) is 92-98°C, and the temperature of the ammonia evaporation wastewater discharged from the bottom of the ammonia evaporation tower (T03) is 102-110°C; the concentration of the ammonia water in the ammonia water buffer tank (L03) is 12-20wt%.

10. The process for cooling and purifying raw gas according to claim 7, characterized in that: The heavy tar is a substance with a boiling point greater than 180°C and less than or equal to 300°C, including asphaltenes, anthracene, phenanthrene, carbazole, quinoline and xylenol; the medium oil product is a substance with a boiling point greater than 85°C and less than or equal to 180°C, including naphthalene, methylnaphthalene, indole, dimethylnaphthalene and phenol; the light oil product is a substance with a boiling point greater than 50 and less than or equal to 85°C, including benzene, toluene, xylene and pyridine.

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