Carbon black tail gas purification and cyclic utilization system

Abstract

The invention relates to the technical field of carbon black tail gas utilization, and discloses a carbon black tail gas purification and cyclic utilization system which comprises a flue gas heat exchanger, a spray scrubbing tower, a flue gas cooler, a gas-liquid separator, a tail gas preheater, a tail gas mixer and a combustion chamber, according to the carbon black tail gas purification and cyclic utilization system, through the combination of the flue gas heat exchanger, the spray washing tower, the flue gas cooler, the gas-liquid separator and other devices, the energy utilization efficiency is greatly improved, meanwhile, after tail gas cyclic utilization is achieved through the system, the energy consumption of carbon black production can be remarkably reduced, and the energy cost is saved. And by recycling the carbon black tail gas, the use of fuel oil can be saved, so that the production cost can be reduced, and the market competitiveness of the product can be improved. The stable combustion temperature and the impurity-reduced tail gas are used as fuel, so that the stability of a carbon black production process is improved, the quality of the carbon black is improved, and the requirement of the market on high-quality carbon black is met.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon black tail gas utilization, in particular to a carbon black tail gas purification and recycling system. Background Art

[0002] Carbon black production involves the combustion of coal tar and air, generating a high-temperature, high-velocity airflow that flows axially through a throat at the rear of the combustion chamber. Feedstock oil is then injected radially into the throat, where it undergoes high-temperature cracking within the reactor, producing carbon black. The collected carbon black is then fed through a blower to a pelletizer, where it is pelletized into granules approximately 1mm in diameter. The finished carbon black product is then dried in a dryer and sent to product storage tanks for packaging and storage. A portion of the separated carbon black exhaust is fed into a boiler for combustion to generate electricity, while the excess is discharged. Since the discharged carbon black exhaust has a certain calorific value, discharging it not only wastes energy but also pollutes the environment. Summary of the Invention

[0003] In order to solve the problems raised in the above background technology, the present invention is implemented through the following technical solutions: a carbon black tail gas purification and recycling system, the system comprising: The flue gas heat exchanger is used to exchange heat between the carbon black tail gas at 200-230℃ and 2500Pa and the tail gas at normal temperature, reducing the high temperature of the carbon black tail gas to 120℃; The spray scrubber adopts a multi-layer uniform spray structure to further cool the exhaust gas to 70-90°C and remove dust from the exhaust gas; The flue gas cooler, including a circulating water heat exchange section and a chilled water heat exchange section, is used to reduce the exhaust gas temperature to 40-60°C and condense the water vapor carried in the exhaust gas; Gas-liquid separator, used to separate liquid water from tail gas; The tail gas preheater uses the waste heat from the high-temperature flue gas of the reactor to heat the tail gas to 120-150℃; Exhaust gas mixer, used to fully mix the preheated exhaust gas with the heated air; The combustion chamber is used for the mixed combustion of tail gas and fuel oil or natural gas, and provides heat to the carbon black reactor.

[0004] Furthermore, the normal temperature exhaust gas needs to be washed, cooled, dehydrated and pressurized before heat exchange with the carbon black exhaust gas. After heat exchange, the normal temperature exhaust gas is heated to 120-150°C and then further heated in the heater of the carbon black waste heat comprehensive utilization system.

[0005] Furthermore, the washing water in the spray washing tower is used after heat exchange with the circulating water in the liquid accumulation tank; The condensed water precipitated from the carbon black tail gas is filtered and then enters the liquid storage tank as circulating water.

[0006] Furthermore, a quenching water tank is provided outside the liquid accumulation tank, and a filter and a spray water pump are sequentially provided at the water outlet of the liquid accumulation tank; The filtered circulating water in the liquid accumulation tank is cooled by a quenching water tank, and the cooled circulating water is transported to the spray washing tower by a spray water pump.

[0007] Furthermore, the flue gas cooler is provided with an inlet 2 on the bottom side, and an outlet 2 on the top side. A chilled water heat exchange part and a circulating water heat exchange part are provided in the middle section of the flue gas cooler, and coils are provided inside the circulating water heat exchange part and the chilled water heat exchange part. The lower end of the circulating water heat exchange part is provided with a circulating water inlet, and the upper end is provided with a circulating water outlet, and the lower end of the chilled water heat exchange part is provided with a chilled water inlet, and the upper end is provided with a chilled water outlet; A second drain outlet is provided at the bottom of the flue gas cooler.

[0008] Furthermore, the circulating water in the flue gas cooler is heated to 40-45°C by heat exchange and then sent to the cooling tower of the owner's circulating water system for cooling and then recycled; After the chilled water is heated to 13-17℃, it is sent to the owner's chilled water system for cooling in the freezing tank before being recycled.

[0009] Furthermore, a portion of the tail gas separated by the gas-liquid separator enters a Roots pressure blower for pressurization.

[0010] Furthermore, the tail gas preheater utilizes the waste heat of the high-temperature flue gas discharged from the reactor to preheat the tail gas.

[0011] Furthermore, part of the tail gas separated by the gas-liquid separator enters the tail gas preheater, and part enters the flue gas heat exchanger as normal temperature gas.

[0012] A method for purifying and recycling carbon black tail gas, comprising the following steps: S1, cool the carbon black tail gas at 200-230℃ and 2500Pa to 120℃ through a flue gas heat exchanger; S2, the carbon black tail gas enters the spray washing tower for spray washing and cooling, the temperature drops to 70-90℃, and the dust content does not exceed 10mg / Nm³; S3, carbon black tail gas exchanges heat with circulating water and chilled water in the flue gas cooler, the temperature drops to 40-60℃, and the water vapor in the tail gas condenses into condensed water; S4, the tail gas is separated from the liquid water by the gas-liquid separator, and the separated tail gas is pressurized to the cracking pressure of 60-75KPa in the furnace by the No. 1 pressure blower; S5. A portion of the pressurized tail gas enters the tail gas preheater and is preheated to 120-150°C. The preheated tail gas is mixed with the heated air in the tail gas mixer and then enters the combustion chamber to be mixed with coal tar or natural gas for combustion.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. The carbon black tail gas purification and recycling system greatly improves energy utilization efficiency through the combination of flue gas heat exchanger, spray scrubber, flue gas cooler, gas-liquid separator and other equipment. At the same time, after the system realizes tail gas recycling, it can significantly reduce the energy consumption of carbon black production and save energy costs.

[0014] 2. The carbon black tail gas purification and recycling system can save fuel oil by recycling the carbon black tail gas, thereby reducing production costs and improving product market competitiveness.

[0015] 3. The carbon black tail gas purification and recycling system uses tail gas with stable combustion temperature and reduced impurities as fuel, which is beneficial to improving the stability of the carbon black production process, thereby improving the quality of carbon black and meeting the market demand for high-quality carbon black.

[0016] 4. The carbon black tail gas purification and recycling system can reduce the pollution of tail gas emissions to the environment and realize the recycling of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic flow chart of the carbon black tail gas purification and recycling system of the present invention; Figure 2 Schematic diagram of equipment layout in the carbon black tail gas purification and recycling system of the present invention; Figure 3 This is a front view of the flue gas heat exchanger structure of the present invention; Figure 4 This is a top view of the flue gas heat exchanger structure of the present invention; Figure 5 This is a front view of the spray scrubber structure of the present invention; Figure 6 This is a front view of the flue gas cooler structure of the present invention; Figure 7 This is a side view of the flue gas cooler structure of the present invention; Figure 8 This is the front view of the gas-liquid separator structure of the present invention.

[0018] In the figure: 1. Flue gas heat exchanger; 101. Carbon black tail gas inlet; 102. Inspection port 1; 103. Normal temperature tail gas inlet; 104. Normal temperature tail gas outlet; 105. Inspection port 2; 106. Carbon black tail gas outlet; 2. Spray scrubber; 201. Inlet 1; 202. Spray pipe; 203. Outlet 1; 204. Drain outlet 1; 3. Flue gas cooler; 301. Inlet 2; 302. Circulating water heat exchange unit; 3021. Circulating water inlet; 3022. Circulating water outlet; 303. Chilled water heat exchange unit; 3031. Chilled water inlet; 3032. Chilled water outlet; 304. Outlet 2; 305. Drain outlet 2; 4. Gas-liquid separator; 401. Inlet 3; 402. Centrifugal zone; 403. Outlet 3; 404. Drain outlet 3; 5. Liquid accumulation tank; 20. Carbon black tail gas pressurization end; 21. Normal temperature tail gas pressurization end; 22. Online heat exchange system end; 23. Venting end; 30. Cooling tower of the owner's circulating water system; 31. Refrigeration tank of the owner's chilled water system; 32. Low-temperature circulating water terminal; 33. High-temperature circulating water terminal; 40. No. 1 booster fan; 41. No. 2 booster fan; 50. Filter; 51. Spray water pump; 52. Quick cooling water tank. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] The embodiment of the carbon black tail gas purification and recycling system is as follows: See also Figures 1-8 , a carbon black tail gas purification and recycling system, the system comprising: The flue gas heat exchanger 1 is used to exchange heat between carbon black exhaust gas at 200-230°C and 2500Pa and normal temperature exhaust gas, so that the high-temperature carbon black exhaust gas is reduced to 120°C. The carbon black exhaust gas is transported to the flue gas heat exchanger 1 from the carbon black exhaust gas pressurizing end 20. The carbon black exhaust gas comes from the exhaust gas generated in the carbon black production, and the normal temperature exhaust gas is transported to the flue gas heat exchanger 1 from the normal temperature exhaust gas pressurizing end 21; the normal temperature exhaust gas needs to be washed, cooled, dehydrated and pressurized before heat exchange with the carbon black exhaust gas. After heat exchange, the normal temperature exhaust gas is heated to 120-150°C, and then further heated in the heater of the carbon black waste heat comprehensive utilization system at the online heat exchange system end 22. The online heat exchange system uses the heat generated in the carbon black production process to heat the 120-150°C exhaust gas to 250-350°C through the online secondary exhaust gas heat exchanger.

[0021] It should be noted that a carbon black exhaust gas inlet 101 is provided on the side of the bottom of the flue gas heat exchanger 1, a carbon black exhaust gas outlet 106 is provided on the side of the top, a normal temperature exhaust gas inlet 103 is provided on the lower end side of the middle section of the flue gas heat exchanger 1, and a normal temperature exhaust gas outlet 104 is provided on the upper end side of the middle section; an inspection port 1 102 is provided at the position opposite to the carbon black exhaust gas inlet 101 at the bottom of the flue gas heat exchanger 1, and an inspection port 2 105 is provided on the top of the flue gas heat exchanger 1; the carbon black exhaust gas and the normal temperature exhaust gas enter the interior of the flue gas heat exchanger 1 through the carbon black exhaust gas inlet 101 and the normal temperature exhaust gas inlet 103 respectively to achieve heat exchange.

[0022] The spray washing tower 2 adopts a multi-layer uniform spray structure, and adopts a countercurrent spraying method of spraying water and exhaust gas to reduce the exhaust gas temperature, and at the same time wash and purify the water vapor and impurities in the exhaust gas; the spray washing tower 2 is used to further cool the exhaust gas to 70-90°C and remove dust from the exhaust gas; the washing water in the spray washing tower 2 is used after heat exchange with the circulating water in the liquid accumulation tank 5; the condensed water precipitated in the carbon black exhaust is filtered and then enters the liquid accumulation tank 5 as circulating water.

[0023] The liquid accumulation tank 5 is provided with a quenching water tank 52 on the outside of the liquid accumulation tank 5, and the water outlet end of the liquid accumulation tank 5 is provided with a filter 50 and a spray water pump 51 in sequence; the quenching water tank 52 is used to cool the filtered circulating water in the liquid accumulation tank 5, and the spray water pump 51 is used to transport the cooled circulating water to the spray washing tower 2.

[0024] It should be noted that an inlet 201 is provided on the side of the bottom of the spray washing tower 2, and an outlet 203 is provided on the top. Multiple groups of spray pipes 202 are provided inside the spray washing tower 2 from top to bottom. The spray pipes 202 spray washing water downward, and a drain outlet 204 is provided at the bottom of the spray washing tower 2; the exhaust gas enters the interior of the spray washing tower 2 through the inlet 201, and then transports the exhaust gas upward, so that the exhaust gas passes through the washing water sprayed by multiple groups of spray pipes 202 in turn; the washed exhaust gas is finally output through the outlet 203, and the washing water is discharged from the drain outlet 204, and enters the liquid accumulation tank 5 after sedimentation and filtration.

[0025] The flue gas cooler 3 includes a circulating water heat exchange section and a chilled water heat exchange section, which is used to reduce the exhaust gas temperature to 40-60°C and condense the water vapor carried in the exhaust gas. The circulating water in the flue gas cooler 3 is heated to 40-45°C through heat exchange and then sent to the owner's circulating water system cooling tower 30 for cooling and then recycled. The chilled water is heated to 13-17°C and then sent to the owner's chilled water system freezing tank 31 for cooling and then recycled.

[0026] It should be noted that an inlet 2 301 is provided on the bottom side of the flue gas cooler 3, and an outlet 2 304 is provided on the top side. A chilled water heat exchange part 303 and a circulating water heat exchange part 302 are distributed above and below the middle section of the flue gas cooler 3; coils are provided inside the circulating water heat exchange part 302 and the chilled water heat exchange part 303, and a circulating water inlet 3021 is provided at the lower end of the circulating water heat exchange part 302, and a circulating water outlet 3022 is provided at the upper end; a chilled water inlet 3031 is provided at the lower end of the chilled water heat exchange part 303, and a chilled water outlet 3032 is provided at the upper end; a drain outlet 2 305 is provided at the bottom of the flue gas cooler 3. The exhaust gas enters the flue gas cooler 3 through the second inlet 301, and then passes through the circulating water heat exchange part 302 and the chilled water heat exchange part 303 in sequence to achieve cooling. The low-temperature circulating water enters the corresponding coil from the circulating water inlet 3021, and the high-temperature circulating water is discharged from the coil from the circulating water outlet 3022. The low-temperature chilled water enters the corresponding coil from the chilled water inlet 3031, and the high-temperature chilled water is discharged from the coil from the chilled water outlet 3032; the water vapor carried in the exhaust gas is condensed and discharged from the second drain outlet 305.

[0027] The high-temperature circulating water discharged from the coil enters the owner's circulating water system cooling tower 30 for cooling, and the cooled circulating water re-enters the coil for use through the circulating water inlet 3021; ​​the high-temperature chilled water discharged from the coil enters the owner's chilled water system freezing tank 31 for cooling, and the cooled chilled water re-enters the coil for use through the chilled water inlet 3031.

[0028] Gas-liquid separator 4 is a centrifugal gas-liquid separator equipped with spiral blades that cause the exhaust gas to rotate at high speed within the separator, utilizing centrifugal force to achieve gas-liquid separation. A drain outlet is provided at the bottom of gas-liquid separator 4 to remove the separated condensed water. Gas-liquid separator 4 is used to separate liquid water from the exhaust gas. A portion of the exhaust gas separated by gas-liquid separator 4 enters the Roots booster blower (No. 2 booster blower 41) for pressurization. A portion of the exhaust gas separated by gas-liquid separator 4 enters the exhaust preheater, while a portion enters the flue gas heat exchanger 1 as ambient temperature gas.

[0029] The tail gas at room temperature enters the flue gas heat exchanger 1 through the normal temperature tail gas pressurizing end 21 , and another part of the tail gas is discharged through the venting end 23 .

[0030] It should be noted that an inlet three 401 is provided on the side of the bottom of the gas-liquid separator 4, an outlet three 403 is provided on the side of the top, at least two groups of centrifugal zones 402 are provided inside the middle section of the gas-liquid separator 4, and a drain three 404 is provided at the bottom of the gas-liquid separator 4; the exhaust gas enters the gas-liquid separator 4 through the inlet three 401, and then enters the centrifugal zone 402 to realize gas-liquid separation, and the separated exhaust gas is discharged through the outlet three 403, and the separated liquid is discharged through the drain three 404.

[0031] The tail gas preheater uses a tube heat exchanger to heat the tail gas to 120-150°C using the waste heat of the high-temperature flue gas discharged from the reactor. The tail gas preheater uses the waste heat of the high-temperature flue gas discharged from the reactor to preheat the tail gas.

[0032] Exhaust gas mixer, used to fully mix the preheated exhaust gas with the heated air; The combustion chamber is built with high-temperature resistant and heat-insulating materials. It is used for the mixed combustion of exhaust gas and fuel oil or natural gas, and provides heat to the carbon black reactor.

[0033] A method for purifying and recycling carbon black tail gas, comprising the following steps: S1, cool the carbon black tail gas at 200-230℃ and 2500Pa to 120℃ through flue gas heat exchanger 1; S2, carbon black tail gas enters spray washing tower 2 for spray washing and cooling, the temperature drops to 70-90℃, and the dust content does not exceed 10mg / Nm³; S3, carbon black tail gas exchanges heat with circulating water and chilled water in flue gas cooler 3, the temperature drops to 40-60℃, and the water vapor in the tail gas condenses into condensed water; S4, the tail gas passes through the gas-liquid separator 4 to separate the liquid water therein, and a portion of the separated tail gas is pressurized to the furnace cracking pressure of 60-75KPa by the No. 1 pressure blower 40; S5. A portion of the pressurized tail gas enters the tail gas preheater and is preheated to 120-150°C. The preheated tail gas is mixed with the heated air in the tail gas mixer and then enters the combustion chamber to be mixed with coal tar or natural gas for combustion.

[0034] Among them, the parameters of each equipment in the carbon black tail gas purification and recycling system are as follows: Equipment parameters of flue gas heat exchanger:

[0035] Equipment parameters of spray scrubber:

[0036] Equipment parameters of flue gas cooler:

[0037] Equipment parameters of gas-liquid separator:

[0038] Equipment parameters of spray water pump:

[0039] Physical indicators in the system: Pressurized air indicators:

[0040] Circulating water indicators:

[0041] Chilled water indicators:

[0042] Indicators after system purification:

[0043] Process flow of carbon black tail gas purification and recycling system: Process flow: The high-temperature carbon black exhaust gas from the carbon black system exhaust pressure fan with a temperature of about 200-230℃ and a pressure of about 2500Pa enters the flue gas heat exchanger 1 for heat exchange with the normal-temperature exhaust gas that has been washed, cooled, dehydrated and pressurized. The high-temperature exhaust gas is reduced to about 120℃ and then enters the spray washing tower 2 at the rear end; among them, the normal-temperature exhaust gas is heated to about 120-150℃ and further heated in the heater of the carbon black waste heat comprehensive utilization system.

[0044] The exhaust gas entering spray scrubber 2 is scrubbed, further cooling it and removing any residual dust. To reduce water usage during the scrubbing process, the water is recycled. To lower its temperature, the water is heat-exchanged with circulating water before use. Condensed water from the exhaust gas is filtered and then deposited in liquid storage tank 5 for use as circulating water.

[0045] After scrubbing, the exhaust gas, at a temperature of approximately 70-90°C, continues to enter the flue gas cooler 3 at the rear end, where it exchanges heat with circulating water and chilled water, respectively. The flue gas cooler 3 has a circulating water section at the bottom and a chilled water section at the top. After heat exchange, the exhaust gas temperature drops to approximately 40-60°C. The water vapor carried in the exhaust gas is condensed into liquid water, which flows from the bottom of the flue gas cooler 3 into the liquid storage tank 5. The circulating water temperature rises from 32°C (low-temperature circulating water end 32) to approximately 42°C (high-temperature circulating water end 33), where it is cooled in the cooling tower 30 of the owner's circulating water system before being recycled. The chilled water temperature rises from 8-10°C to approximately 15°C, where it is cooled in the chiller tank 31 of the owner's chilled water system before being recycled.

[0046] The tail gas, at approximately 40°C, carries a small amount of liquid water and enters the gas-liquid separator 4. After the liquid water is separated, the tail gas is pressurized by a Roots blower and then enters the carbon black waste heat comprehensive utilization system. Finally, it enters the carbon black combustion chamber, where it is mixed with fuel oil or natural gas and burned to provide heat energy for the carbon black reaction. The separated water enters the liquid storage tank 5 and is subsequently recycled to the spray scrubber 2.

[0047] Among them, the carbon black waste heat comprehensive utilization system includes an exhaust gas preheater, an exhaust gas mixer and a combustion chamber. The exhaust gas preheater adopts a tube heat exchanger, which uses the waste heat of the high-temperature flue gas discharged from the reactor to preheat the exhaust gas, increase the temperature of the exhaust gas entering the combustion chamber, and enhance the combustion effect.

[0048] The mixed combustion system consists of an exhaust gas mixer and a combustion chamber. The exhaust gas mixer fully mixes the preheated exhaust gas with the heated air. The combustion chamber is built with high-temperature resistant and heat-insulating materials to ensure stable combustion and effective heat transfer to the carbon black reactor.

[0049] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A carbon black tail gas purification and recycling system, characterized by: The system comprises: The flue gas heat exchanger is used to exchange heat between the carbon black tail gas at 200-230℃ and 2500Pa and the tail gas at normal temperature, reducing the high temperature of the carbon black tail gas to 120℃; The spray scrubber adopts a multi-layer uniform spray structure to further cool the exhaust gas to 70-90°C and remove dust from the exhaust gas; The flue gas cooler, including a circulating water heat exchange section and a chilled water heat exchange section, is used to reduce the exhaust gas temperature to 40-60°C and condense the water vapor carried in the exhaust gas; Gas-liquid separator, used to separate liquid water from tail gas; The tail gas preheater uses the waste heat from the high-temperature flue gas of the reactor to heat the tail gas to 120-150℃; Exhaust gas mixer, used to fully mix the preheated exhaust gas with the heated air; The combustion chamber is used for the mixed combustion of tail gas and fuel oil or natural gas, and provides heat to the carbon black reactor.

2. The carbon black tail gas purification and recycling system according to claim 1, characterized in that: The normal temperature tail gas needs to be washed, cooled, dehydrated and pressurized before heat exchange with the carbon black tail gas. After heat exchange, the normal temperature tail gas is heated to 120-150°C and then further heated in the heater of the carbon black waste heat comprehensive utilization system.

3. The carbon black tail gas purification and recycling system according to claim 1, characterized in that: The washing water in the spray washing tower is used after heat exchange with the circulating water in the liquid accumulation tank; The condensed water precipitated from the carbon black tail gas is filtered and then enters the liquid storage tank as circulating water.

4. The carbon black tail gas purification and recycling system according to claim 3, characterized in that: A quenching water tank is provided outside the liquid accumulation tank, and a filter and a spray water pump are sequentially provided at the water outlet of the liquid accumulation tank; The filtered circulating water in the liquid accumulation tank is cooled by a quenching water tank, and the cooled circulating water is transported to the spray washing tower by a spray water pump.

5. The carbon black tail gas purification and recycling system according to claim 1, characterized in that: The flue gas cooler is provided with an inlet 2 on the bottom side, and an outlet 2 on the top side. A chilled water heat exchange part and a circulating water heat exchange part are provided in the middle section of the flue gas cooler, and coils are provided inside the circulating water heat exchange part and the chilled water heat exchange part. The lower end of the circulating water heat exchange part is provided with a circulating water inlet, and the upper end is provided with a circulating water outlet, and the lower end of the chilled water heat exchange part is provided with a chilled water inlet, and the upper end is provided with a chilled water outlet; A second drain outlet is provided at the bottom of the flue gas cooler.

6. The carbon black tail gas purification and recycling system according to claim 4, characterized in that: The circulating water in the flue gas cooler is heated to 40-45°C by heat exchange and then sent to the cooling tower of the owner's circulating water system for cooling and recycling; After the chilled water is heated to 13-17℃, it is sent to the owner's chilled water system for cooling in the freezing tank before being recycled.

7. The carbon black tail gas purification and recycling system according to claim 1, characterized in that: A portion of the tail gas separated by the gas-liquid separator enters the Roots pressure blower for pressurization.

8. The carbon black tail gas purification and recycling system according to claim 1, characterized in that: The tail gas preheater utilizes the waste heat of the high-temperature flue gas discharged from the reactor to preheat the tail gas.

9. The carbon black tail gas purification and recycling system according to claim 7, characterized in that: A portion of the tail gas separated by the gas-liquid separator enters the tail gas preheater, and a portion enters the flue gas heat exchanger as normal temperature gas.

10. A method for purifying and recycling carbon black tail gas, applied to the carbon black tail gas purification and recycling system according to claim 1, characterized in that: The following methods are included: S1, cool the carbon black tail gas at 200-230℃ and 2500Pa to 120℃ through a flue gas heat exchanger; S2, the carbon black tail gas enters the spray washing tower for spray washing and cooling, the temperature drops to 70-90℃, and the dust content does not exceed 10mg / Nm³; S3, carbon black tail gas exchanges heat with circulating water and chilled water in the flue gas cooler, the temperature drops to 40-60℃, and the water vapor in the tail gas condenses into condensed water; S4, the tail gas is separated from the liquid water by the gas-liquid separator, and the separated tail gas is pressurized to the furnace cracking pressure of 60-75KPa by the No. 1 pressure blower; S5. A portion of the pressurized tail gas enters the tail gas preheater and is preheated to 120-150°C. The preheated tail gas is mixed with the heated air in the tail gas mixer and then enters the combustion chamber to be mixed with coal tar or natural gas for combustion.

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