A VOCs gas treatment system
The VOCs gas treatment system, consisting of a multi-stage compressor and cooler, solves the problem of nitrogen not being recovered and reused in the exhaust gas, achieving resource reuse and safety improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHAANXI CARBONIFICATION ENERGY CO LTD
- Filing Date
- 2025-07-28
- Publication Date
- 2026-07-31
AI Technical Summary
In existing technologies, methanol tail gas treatment fails to recover and reuse nitrogen in the tail gas, resulting in resource waste and increased operating costs, while also posing environmental pollution risks.
The processing module, consisting of a multi-stage compressor and cooler, combined with a gas-liquid separator and a resource recovery terminal device, performs multi-stage compression, cooling and separation of exhaust gas to recover nitrogen and methanol, thereby achieving resource reuse.
It achieves the complete recovery and utilization of both refined and crude exhaust gases, reducing resource waste and operating costs, and improving the system's safety performance.
Smart Images
Figure CN224573476U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of chemical technology, specifically a VOCs gas treatment system. Background Technology
[0002] In traditional coal-to-methanol processes, crude methanol needs to be purified by distillation to remove moisture and impurities. After being produced from the distillation column, refined methanol is temporarily stored in a refined methanol tank. After passing analysis, it is transferred to the finished product tank and protected by nitrogen. However, the diurnal temperature variation still causes high-concentration methanol vapor to escape through the breather valve. If it is directly released into the air (the main components are methanol and nitrogen), it will cause two problems: first, it will result in the loss of methanol products; second, it will cause environmental pollution, and long-term exposure may lead to occupational diseases. Therefore, a treatment device is needed to recover and treat the exhaust gas.
[0003] Currently, a two-stage water washing scheme is often used for treating refined methanol tail gas. The main process is that the tail gas enters the tail gas collection manifold, is pressurized by a fan and sent to the first and second stage water washing towers. The washed gas is then separated by a gas-water separator and discharged on-site after meeting the standards. However, this treatment method fails to recover and reuse the nitrogen present in the tail gas, which not only wastes resources but also increases operating costs. Utility Model Content
[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a VOCs gas treatment system.
[0005] To achieve the above objectives, this utility model provides the following technical solution: A VOCs gas treatment system includes an intake pipe for inputting exhaust gas, a treatment module on one side of the intake pipe, and a gas-liquid separator connected to the output end of the treatment module. The processing module includes a multi-stage compression structure and several coolers, with the coolers connected in series with the compression sections of the multi-stage compression structure to perform multi-stage compression of the gas. The inlet of the first section of the multi-stage compression structure is connected to the air intake pipeline, and the outlet of the last section of the multi-stage compression structure is connected to the gas-liquid separator. The output end of the gas-liquid separator is connected to a first pipeline and a second pipeline, respectively; The processing module also includes a resource recovery terminal device; In the treatment of refined tail gas, the resource recovery terminal devices are a hydrogen sulfide concentration tower and a distillation tower; The ends of the first and second pipelines furthest from the gas-liquid separator are connected to the input ends of the hydrogen sulfide concentration tower and the distillation tower, respectively, for nitrogen recovery and methanol recovery and reuse. In the treatment of crude methanol and pre-tower non-condensable gas tail gas, the resource recovery terminal devices are storage devices and fuel gas pipelines. The first and second pipelines are connected to the fuel gas pipeline network and the storage device, respectively, and are used for the use of the separated combustible gas and the storage of the liquid.
[0006] Furthermore, buffer tanks are installed near the inlet and outlet of the multi-stage compression structure to provide pressure stabilization and protection.
[0007] Furthermore, the multi-stage compression is converted into a two-stage compression, and the multi-stage compression structure is a reciprocating compressor; The output end of the intake pipe is connected to a first buffer tank. The output end of the first buffer tank is connected to a first inlet of the reciprocating compressor. The first outlet of the reciprocating compressor is connected to a first cooler. The output end of the first cooler is connected to a connecting pipe. The output end of the connecting pipe is connected to a second buffer tank. The output end of the second buffer tank is connected to a second inlet of the reciprocating compressor. The second outlet of the reciprocating compressor is connected to a third buffer tank. The output end of the third buffer tank is connected to a second cooler. The output end of the second cooler is connected to a gas-liquid separator.
[0008] Furthermore, a return pipe is also connected to the connecting pipe, and the other end of the return pipe is connected to the intake pipe. A regulating valve is installed on the return line to adjust the gas volume.
[0009] Furthermore, the intake pipeline is equipped with an online oxygen content analyzer and a shut-off valve to detect the oxygen content of the incoming gas and stop the gas supply in a timely manner.
[0010] Furthermore, an emergency pipeline is connected between the third buffer tank and the second cooler. One end of the emergency pipeline is connected to the first emergency flare, and an emergency valve is also installed on the emergency pipeline.
[0011] Furthermore, the liquid storage device includes an isobutyl oil tank and a crude methanol tank; The second pipeline is connected to the isobutyl oil tank at the end furthest from the gas-liquid separator. The second pipeline is also connected to a third pipeline, one end of which is connected to the crude methanol tank; The second pipeline is also equipped with an online near-infrared spectroscopy analyzer for real-time fluid detection.
[0012] Furthermore, in the treatment of crude methanol and pre-tower non-condensable gas tail gas, a fourth pipeline is connected to the first pipeline, and the fourth pipeline is connected to the second emergency flare.
[0013] Compared with existing technologies, this VOCs gas treatment system has the following advantages: I. This utility model utilizes a reciprocating compressor and cooler to perform multi-stage compression and cooling, increasing the fluid pressure and reducing the temperature. A gas-liquid separator separates the gas and liquid, transporting them to a resource recovery terminal for processing. Furthermore, the gas above the refined carbide storage tank is completely recovered and reused in the refined carbide tail gas, fed into a hydrogen sulfide concentration tower for secondary waste gas recovery. In the crude carbide tail gas, crude carbide VOCs and pre-tower non-condensable gases are recovered and co-combusted. This achieves complete recovery and reuse of both refined and crude carbide tail gas without the need for emission outlets, solving the problem of resource waste caused by the failure to recover and reuse nitrogen in existing refined carbide tail gas treatments.
[0014] Second, this utility model improves the safety performance of the system by installing an online oxygen content analyzer on the air intake pipe to detect the oxygen concentration in the gas when external gas enters the system in real time, and by installing a corresponding emergency flare on the system. Attached Figure Description
[0015] Figure 1 This is a flowchart of the crude carbide exhaust gas treatment process of this utility model; Figure 2 This is a flowchart of the exhaust gas treatment process of this utility model.
[0016] In the diagram: 1. Online oxygen content analyzer; 2. First buffer tank; 3. Reciprocating compressor; 4. First cooler; 5. Second buffer tank; 6. Third buffer tank; 7. Second cooler; 8. Gas-liquid separator; 9. First pipeline; 10. Second pipeline; 11. Inlet pipeline; 12. Return pipeline; 13. Connecting pipeline. Detailed Implementation
[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0018] like Figure 1-2As shown, this utility model provides a technical solution: a VOCs gas treatment system, including an intake pipe 11 for tail gas input, a treatment module disposed on one side of the intake pipe 11, and a gas-liquid separator 8 connected to the output end of the treatment module. The treatment module includes a multi-stage compression structure and several coolers, with the coolers connected in series with the compression sections of the multi-stage compression structure for multi-stage compression of the gas. The inlet of the first section of the multi-stage compression structure is connected to the intake pipe 11, and the outlet of the last section of the multi-stage compression structure is connected to the gas-liquid separator 8. The output end of the gas-liquid separator 8 is connected to a first pipe... The processing module also includes a resource recovery terminal device; in the treatment of crude methanol tail gas, the resource recovery terminal device is a hydrogen sulfide concentration tower and a distillation tower; the ends of the first pipeline 9 and the second pipeline 10 away from the gas-liquid separator 8 are respectively connected to the input ends of the hydrogen sulfide concentration tower and the distillation tower for nitrogen recovery and methanol recovery and reuse; in the treatment of crude methanol and pre-tower non-condensable gas tail gas, the resource recovery terminal device is a storage device and a fuel gas pipeline network; the first pipeline 9 and the second pipeline 10 are respectively connected to the fuel gas pipeline network and the storage device for the use of the separated combustible gas and the storage of the liquid.
[0019] Buffer tanks are installed near the inlet and outlet of the multi-stage compression structure to provide pressure stabilization and protection. The multi-stage compression is a two-stage compression, and the multi-stage compression structure is a reciprocating compressor 3. The output end of the intake pipe 11 is connected to the first buffer tank 2. The output end of the first buffer tank 2 is connected to the first inlet of the reciprocating compressor 3. The first outlet of the reciprocating compressor 3 is connected to the first cooler 4. The output end of the first cooler 4 is connected to the connecting pipe 13. The output end of the connecting pipe 13 is connected to the second buffer tank 5. The output end of the second buffer tank 5 is connected to the second inlet of the reciprocating compressor 3. The second outlet of the reciprocating compressor 3 is connected to the third buffer tank 6. The output end of the third buffer tank 6 is connected to the second cooler 7. The output end of the second cooler 7 is connected to the gas-liquid separator 8.
[0020] In the treatment of the exhaust gas from the refined tank, gas at 0.1 MPa and 45-55°C from the top of the refined tank enters the inlet pipe 11 through a pipeline. Then, it enters the first buffer tank 2 for pressure stabilization, preventing pressure fluctuations at the inlet of the reciprocating compressor 3 that could cause surge or efficiency reduction. After pressure stabilization, the gas enters the inlet of the reciprocating compressor 3, where it is compressed to 0.25 MPa before entering the first cooler 4 for cooling to 40°C. This reduces the gas temperature, decreases the power consumption of subsequent compression, and prevents damage to downstream equipment due to high temperatures. The cooled gas phase then enters the second buffer tank 5, where its pressure is stabilized at 0.25 MPa to prevent pressure fluctuations or liquid carryover in the reciprocating compressor 3. Damaged gas enters the second-stage inlet of reciprocating compressor 3, where it is compressed to 0.50 MPa. It then enters the third buffer tank 6 for buffering, mitigating the pressure fluctuations after the second-stage compression and protecting the second cooler 7 and gas-liquid separator 8. The gas is then cooled in the second cooler 7 to promote the liquefaction of condensable components in the gas phase, facilitating subsequent separation. After cooling to 30°C, it enters the gas-liquid separator 8, where the gas and liquid phases, pressurized to 0.50 MPa and 30°C, are separated. The separated gas is sent to a low-temperature methanol washing hydrogen sulfide concentration tower for nitrogen recovery and reuse, while the liquid phase is sent to a pre-distillation tower for recycling. This process achieves complete recovery and reuse of the gas above the methanol storage tank in the hydrogen sulfide concentration tower for secondary waste gas recovery and reduces the loss of low-pressure nitrogen.
[0021] In the treatment of crude methanol and pre-tower non-condensable gas tail gas, the reciprocating compressor 3 and the corresponding cooler, along with the buffer tank, are used to achieve two-stage compression and cooling of the gas. Then, the gas phase and liquid phase are separated at 0.45MPa and 30℃. The separated combustible gas is transported to the boiler for co-firing, while the liquid phase is stored in the storage device to achieve the recovery and reuse of VOCs.
[0022] The connecting pipe 13 is also connected to the return pipe 12, and the other end of the return pipe 12 is connected to the intake pipe 11. The return pipe 12 is equipped with a regulating valve to regulate the gas volume. In use, the return pipe 12 is also equipped with a check valve to restrict one-way flow and prevent the gas in the intake pipe 11 from passing through a compression section. When needed, the gas volume is adjusted by controlling the regulating valve so that part of the gas processed by the first cooler 4 flows back to the intake pipe 11 through the return pipe 12, which can prevent the compressor from surging.
[0023] An online oxygen analyzer 1 and a shut-off valve are installed on the inlet pipeline 11 to detect the oxygen content of the incoming gas and stop the gas supply in time. An emergency pipeline is also connected between the third buffer tank 6 and the second cooler 7. One end of the emergency pipeline is connected to the first emergency flare, and an emergency valve is also installed on the emergency pipeline. In use, the online oxygen analyzer 1 and the shut-off valve are both located between the inlet and the return pipeline 12. The online oxygen analyzer 1 detects the oxygen concentration online in real time. When the oxygen content is <0.5%, the gas enters the first buffer tank 2 normally and then passes through equipment such as the reciprocating compressor 3 to compress, cool, and separate the gas. This separates and recovers VOCs and non-condensable gases in the tank area of the coal-to-methanol plant, avoiding the risk of explosion caused by excessive oxygen concentration during the process. When the oxygen content is ≥0.5%, the shut-off valve is automatically closed in an emergency to stop the gas supply, and the gas is introduced into the first emergency flare for incineration through the emergency valve to ensure system safety.
[0024] The liquid storage device includes an isobutyl oil tank and a crude methanol tank; the isobutyl oil tank is connected to the end of the second pipeline 10 away from the gas-liquid separator 8; a third pipeline is also connected to the second pipeline 10, and one end of the third pipeline is connected to the crude methanol tank; a near-infrared spectroscopy online analyzer is also installed on the second pipeline 10 for real-time fluid detection; in use, corresponding control valves are installed on the side of the second pipeline 10 and the third pipeline near the tank body to open or close the pipelines, and then the separated fluid is detected in real time by the near-infrared spectroscopy online analyzer. Based on the detection results, the corresponding second pipeline 10 and the third pipeline are selected to be opened or closed, and the fluid is sent to the isobutyl oil tank or the crude methanol tank through an underground tank.
[0025] In the treatment of crude methanol and pre-tower non-condensable gas tail gas, the first pipeline 9 is connected to the fourth pipeline, which is connected to the second emergency flare. During operation, control valves are installed at the ends of the first and fourth pipelines furthest from the gas-liquid separator 8 to open or close the first and fourth pipelines. Under normal circumstances, the separated gas enters the fuel gas network through the first pipeline 9 and is sent to the boiler for co-firing. In case of emergency, the pipeline is switched to the second emergency flare on the fourth pipeline to ensure system safety. The system is also equipped with corresponding controllers to coordinate the work of various devices to ensure the recovery and treatment of waste gas and emergency handling in case of accidents.
Claims
1. A VOCs gas treatment system, comprising an intake pipe (11) for tail gas input, a treatment module disposed on one side of the intake pipe (11), and a gas-liquid separator (8) connected to the output end of the treatment module, characterized in that: The processing module includes a multi-stage compression structure and several coolers, and the several coolers are connected in series with the compression section of the multi-stage compression structure to compress the gas in multiple stages. One inlet of the multi-stage compression structure is connected to the air intake pipe (11), and the last outlet of the multi-stage compression structure is connected to the gas-liquid separator (8). The output end of the gas-liquid separator (8) is connected to the first pipeline (9) and the second pipeline (10). The processing module also includes a resource recovery terminal device; In the treatment of refined tail gas, the resource recovery terminal device is a hydrogen sulfide concentration tower and a distillation tower; The ends of the first pipeline (9) and the second pipeline (10) that are away from the gas-liquid separator (8) are respectively connected to the input ends of the hydrogen sulfide concentration tower and the distillation tower for nitrogen recovery and methanol recovery and reuse. In the crude methanol and pre-tower non-condensable gas tail gas, the resource recovery terminal device is a storage device and a fuel gas pipeline network; The first pipeline (9) and the second pipeline (10) are respectively connected to the fuel gas pipeline network and the storage device, and are used for the use of the separated combustible gas and the storage of the liquid.
2. The VOCS gas treatment system of claim 1, wherein: Buffer tanks are installed near the inlet and outlet of the multi-segment compression structure to stabilize pressure and provide protection.
3. The VOCS gas treatment system of claim 2, wherein: The multi-stage compression is a two-stage compression, and the multi-stage compression structure is a reciprocating compressor (3). The output end of the intake pipe (11) is connected to the first buffer tank (2), the output end of the first buffer tank (2) is connected to a section of the input port of the reciprocating compressor (3), a section of the outlet of the reciprocating compressor (3) is connected to the first cooler (4), the output end of the first cooler (4) is connected to the connecting pipe (13), the output end of the connecting pipe (13) is connected to the second buffer tank (5), the output end of the second buffer tank (5) is connected to the second section of the inlet of the reciprocating compressor (3), the second section of the outlet of the reciprocating compressor (3) is connected to the third buffer tank (6), the output end of the third buffer tank (6) is connected to the second cooler (7), and the output end of the second cooler (7) is connected to the gas-liquid separator (8).
4. The VOCS gas treatment system of claim 3, wherein: The connecting pipe (13) is also connected to a return pipe (12), and the other end of the return pipe (12) is connected to the intake pipe (11); The return pipeline (12) is equipped with a regulating valve for regulating the gas volume.
5. The VOCS gas treatment system of claim 1, wherein: The intake pipe (11) is also equipped with an online oxygen content analyzer (1) and a shut-off valve, which are used to detect the oxygen content of the incoming gas and stop the gas supply in time.
6. The VOCS gas treatment system according to claim 3, wherein: An emergency pipeline is also connected to the pipeline between the third buffer tank (6) and the second cooler (7). One end of the emergency pipeline is connected to the first emergency flare, and an emergency valve is also installed on the emergency pipeline.
7. The VOCS gas treatment system of claim 1, wherein: It also includes a liquid storage device, which comprises an isobutyl oil tank and a crude methanol tank; The second pipeline (10) is connected to the isobutyl oil tank at the end furthest from the gas-liquid separator (8); The second pipeline (10) is also connected to a third pipeline, one end of which is connected to the crude methanol tank; The second pipeline (10) is also equipped with an online near-infrared spectroscopy analyzer for real-time fluid detection.
8. The VOCS gas treatment system of claim 1, wherein: In the crude methanol and pre-tower non-condensable gas tail gas, the first pipeline (9) is connected to a fourth pipeline, and the fourth pipeline is connected to a second emergency flare.