A tail gas deep capture and reuse system
Patent Information
- Application Number
- CN202621531208.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-29
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2036-09-29
AI Technical Summary
现有低温甲醇洗尾气治理技术中，单级水洗脱除效率低，无法实现超低排放，且稀醇水外排造成物料损耗，存在环保合规风险。
A deep capture and reuse system for exhaust gas is adopted, including an exhaust gas scrubbing tower, a water scrubbing tower, an activated carbon adsorption device, a circulating water condenser, and a methanol recovery tank. Through primary water scrubbing, secondary activated carbon deep adsorption, combined with hot nitrogen reverse regeneration and condensation recovery, deep recovery of methanol is achieved.
This achieves a further reduction in methanol content in exhaust gas, meets ultra-low emission requirements, realizes zero venting and zero waste of methanol, and improves methanol capture and recovery rate.
Smart Images
Figure CN224925863U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of coal chemical tail gas technology, specifically relating to a deep tail gas capture and reuse system. Background Technology
[0002] Low-temperature methanol washing is a mainstream and mature process for removing hydrogen sulfide and carbon dioxide from coal chemical feedstock gas. The unit continuously discharges atmospheric pressure tail gas from the top of the tail gas stripping tower. Current processes only employ simple water washing pretreatment and lack deep methanol recovery facilities. Under normal operating conditions, the methanol content in the tail gas is approximately 150 ppm. Due to atmospheric pressure fluctuations, tail gas diffusion is hindered during low-pressure periods, causing methanol and CO to easily accumulate around the unit. This results in continuous methanol loss and poses environmental compliance risks such as excessive VOC emissions and environmental pollution.
[0003] Current exhaust gas treatment solutions in the industry mostly adopt single-stage water washing or direct incineration: single-stage water washing removes methanol up to 80-150 ppm, and methanol is continuously lost as it is released into the air, and it is easy to accumulate when the gas pressure is low, which may cause environmental pollution risks. Incineration directly destroys methanol, and solvent recovery and utilization cannot be achieved, and material loss cannot be eliminated. At the same time, traditional exhaust gas treatment solutions do not consider the problem of recovering dilute methanol wastewater generated by the water washing unit, resulting in a waste of methanol resources. Utility Model Content
[0004] The purpose of this invention is to provide a deep capture and reuse system for exhaust gas, which solves the problems of low single-stage water washing removal efficiency, inability to achieve ultra-low emissions, and material loss caused by the discharge of dilute methanol water in the existing low-temperature methanol washing exhaust gas treatment technology.
[0005] This utility model is implemented by the following technical solution: a deep capture and reuse system for exhaust gas, which includes an exhaust gas scrubbing tower, a water scrubbing tower, an activated carbon adsorption device, a circulating water condenser, and a methanol recovery tank. The inlet of the tail gas scrubbing tower is connected to the tail gas outlet pipeline of the tail gas desorption tower, the outlet of the tail gas scrubbing tower is connected to the bottom inlet pipeline of the water scrubbing tower, the top outlet of the water scrubbing tower is connected to the inlet pipeline of the activated carbon adsorption device, the top outlet of the activated carbon adsorption device is connected to the vent pipeline, the bottom outlet of the activated carbon adsorption device is connected to the shell-side inlet pipeline of the circulating water condenser, the shell-side outlet of the circulating water condenser is connected to the inlet pipeline of the methanol recovery tank, and the outlet of the methanol recovery tank is connected to the inlet pipeline of the methanol-water separator via a reflux pump.
[0006] Furthermore, the bottom outlet of the exhaust gas scrubbing tower and the bottom outlet of the water scrubbing tower are respectively connected to the inlet pipeline of the methanol-water separator.
[0007] Furthermore, the activated carbon adsorption device includes two activated carbon adsorption tanks and a heater. The two activated carbon adsorption tanks are arranged in parallel. The inlet of the heater is connected to the nitrogen pipeline, and the outlet of the heater is connected to the inlet pipeline of the activated carbon adsorption tank.
[0008] Furthermore, the washing liquid inlet of the exhaust gas scrubbing tower and the washing liquid inlet of the water scrubbing tower are respectively connected to the demineralized water pipeline.
[0009] The advantages of this invention are: the use of a coupled process of "first-stage water washing and second-stage activated carbon deep adsorption" further reduces the methanol content in the exhaust gas, meeting the requirements for ultra-low emissions; An activated carbon adsorption device, hot nitrogen reverse regeneration, and condensation recovery are used to condense and collect methanol, which is then returned to the feed gas end for reuse. The diluted methanol water from the washing process is sent to a methanol-water separation tower for distillation and recovery, achieving zero venting and zero waste of methanol in the tail gas and improving the methanol capture and recovery rate. Attached Figure Description
[0010] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0011] Figure 1 This is a flowchart of the production system of this utility model; In the diagram: 1. Tail gas scrubbing tower; 2. Water scrubbing tower; 3. Activated carbon adsorption device; 31. Activated carbon adsorption tank; 32. Heater; 4. Circulating water condenser; 5. Methanol recovery tank; 6. Reflux pump; 7. Methanol-water separation tower; 8. Tail gas stripping tower; 9. Demineralized water pipeline; 10. Nitrogen pipeline; 11. Vent pipeline. Detailed Implementation
[0012] Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.
[0013] like Figure 1 As shown, a deep capture and reuse system for exhaust gas includes an exhaust gas scrubbing tower 1, a water scrubbing tower 2, an activated carbon adsorption device 3, a circulating water condenser 4, a methanol recovery tank 5, and a methanol-water separation tower 7.
[0014] The inlet of the tail gas scrubbing tower 1 is connected to the tail gas outlet pipeline of the tail gas stripping tower 8. The methanol-containing tail gas discharged from the tail gas stripping tower 8 enters the bottom of the tail gas scrubbing tower 1 via the pipeline. The washing liquid inlet of the tail gas scrubbing tower 1 is connected to the demineralized water pipeline 9. The demineralized water is introduced from the top of the tail gas scrubbing tower 1 as the washing liquid, contacting the tail gas flowing upwards in a counter-current manner to perform preliminary washing of the tail gas and absorb methanol vapor from the tail gas. The bottom outlet of the tail gas scrubbing tower 1 is connected to the inlet pipeline of the methanol-water separator 7. The washed aqueous solution (containing methanol) is discharged from the bottom of the tail gas scrubbing tower 1 and returned to the methanol-water separator 7 for recycling.
[0015] The outlet of the tail gas scrubbing tower 1 is connected to the bottom inlet pipeline of the water scrubbing tower 2. The tail gas, after preliminary scrubbing, exits from the top of the tail gas scrubbing tower 1 and enters the bottom of the water scrubbing tower 2. The washing liquid inlet of the water scrubbing tower 2 is connected to the demineralized water pipeline 9. The demineralized water is introduced from the top of the water scrubbing tower 2 and comes into countercurrent contact with the tail gas flowing upwards, performing secondary water scrubbing and absorption on the tail gas to further absorb residual methanol vapor. The bottom outlet of the water scrubbing tower 2 is connected to the inlet pipeline of the methanol-water separator 7. The aqueous solution after scrubbing exits from the bottom of the water scrubbing tower 2 and returns to the methanol-water separator 7 for recycling.
[0016] The top outlet of the water washing tower 2 is connected to the inlet pipeline of the activated carbon adsorption device 3. The exhaust gas after secondary water washing is discharged from the top of the water washing tower 2 and enters the activated carbon adsorption tank 31 of the activated carbon adsorption device 3 for deep adsorption treatment.
[0017] The activated carbon adsorption device 3 includes two activated carbon adsorption tanks 31 and a heater 32. The two activated carbon adsorption tanks 31 are connected in parallel. Each tank is filled with activated carbon to adsorb trace amounts of methanol remaining in the exhaust gas. The inlet of the heater 32 is connected to the nitrogen line 10, and the outlet is connected to the inlet line of each activated carbon adsorption tank 31. When one activated carbon adsorption tank 31 becomes saturated, it switches to the standby tank 31 for continued operation. The saturated activated carbon adsorption tank 31 undergoes thermal desorption and regeneration by introducing heated nitrogen through the heater 32. The heated nitrogen is then introduced into the saturated activated carbon adsorption tank 31 to thermally desorb the activated carbon, and the desorbed methanol vapor is discharged along with the nitrogen.
[0018] The top outlet of the activated carbon adsorption device 3 is connected to the venting pipeline 11. The exhaust gas treated by activated carbon adsorption is discharged from the top of the activated carbon adsorption tank 31 and discharged in compliance with standards through the venting pipeline 11.
[0019] The bottom outlet of the activated carbon adsorption unit 3 is connected to the shell-side inlet pipeline of the circulating water condenser 4. Methanol vapor (containing nitrogen) generated during desorption from the activated carbon adsorption tank 31 is discharged from the bottom of the activated carbon adsorption tank 31 and enters the shell side of the circulating water condenser 4. The circulating water condenser 4 uses circulating water as the cooling medium to condense the methanol vapor into liquid. Nitrogen is discharged and recovered from the circulating water condenser 4. The shell-side outlet of the circulating water condenser 4 is connected to the inlet pipeline of the methanol recovery tank 5. The condensed methanol liquid is collected in the methanol recovery tank 5.
[0020] The outlet of methanol recovery tank 5 is connected to the inlet pipeline of methanol-water separator 7 via reflux pump 6. The methanol liquid collected in methanol recovery tank 5 is transported back to methanol-water separator 7 for recycling via reflux pump 6, achieving deep recovery of methanol.
[0021] The working process of this utility model is as follows: The methanol-containing tail gas discharged from tail gas stripping tower 8 enters the bottom of tail gas scrubbing tower 1, where it undergoes preliminary scrubbing by countercurrent contact with demineralized water introduced from the top. The scrubbing aqueous solution is discharged from the bottom of tail gas scrubbing tower 1 and returned to methanol-water separator 7. The tail gas after preliminary scrubbing is discharged from the top of tail gas scrubbing tower 1 and enters the bottom of water scrubbing tower 2, where it undergoes secondary water scrubbing and absorption by countercurrent contact with demineralized water introduced from the top. The water scrubbing aqueous solution is discharged from the bottom of water scrubbing tower 2 and returned to methanol-water separator 7. The tail gas after secondary water scrubbing is discharged from the top of water scrubbing tower 2 and enters activated carbon adsorption unit 3.
[0022] In the activated carbon adsorption device 3, the exhaust gas passes through the activated carbon adsorption tank 31, where trace amounts of methanol are adsorbed by the activated carbon. The purified exhaust gas is discharged from the top of the activated carbon adsorption tank 31 and discharged through the vent pipeline 11 in compliance with emission standards. An online methanol concentration detector is installed on the vent pipeline 11 to monitor the methanol concentration in the exhaust gas in real time. When one activated carbon adsorption tank 31 becomes saturated, it is switched to a standby activated carbon adsorption tank 31 for continued operation. The saturated activated carbon adsorption tank 31 undergoes thermal desorption by introducing heated nitrogen gas through the heater 32. The desorbed methanol vapor enters the circulating water condenser 4 and is condensed into liquid. The condensate is collected in the methanol recovery tank 5 and then returned to the methanol-water separator 7 for recycling via the reflux pump 6.
[0023] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A deep exhaust gas capture and reuse system, characterized in that, It includes a tail gas scrubbing tower, a water scrubbing tower, an activated carbon adsorption device, a circulating water condenser, and a methanol recovery tank; The inlet of the tail gas scrubbing tower is connected to the tail gas outlet pipeline of the tail gas desorption tower, the outlet of the tail gas scrubbing tower is connected to the bottom inlet pipeline of the water scrubbing tower, the top outlet of the water scrubbing tower is connected to the inlet pipeline of the activated carbon adsorption device, the top outlet of the activated carbon adsorption device is connected to the vent pipeline, the bottom outlet of the activated carbon adsorption device is connected to the shell-side inlet pipeline of the circulating water condenser, the shell-side outlet of the circulating water condenser is connected to the inlet pipeline of the methanol recovery tank, and the outlet of the methanol recovery tank is connected to the inlet pipeline of the methanol-water separator via a reflux pump.
2. The exhaust gas deep capture and reuse system according to claim 1, characterized in that, The bottom outlet of the exhaust gas scrubbing tower and the bottom outlet of the water scrubbing tower are respectively connected to the inlet pipeline of the methanol-water separator.
3. The exhaust gas deep capture and reuse system according to claim 2, characterized in that, The activated carbon adsorption device includes two activated carbon adsorption tanks and a heater. The two activated carbon adsorption tanks are arranged in parallel. The inlet of the heater is connected to a nitrogen pipeline, and the outlet of the heater is connected to the inlet pipeline of the activated carbon adsorption tank.
4. The exhaust gas deep capture and reuse system according to claim 3, characterized in that, The washing liquid inlet of the exhaust gas scrubbing tower and the washing liquid inlet of the water scrubbing tower are respectively connected to the demineralized water pipeline.