CN103316565B - Efficient enrichment and separation equipment for ultralow-concentration gas - Google Patents

Abstract

A high-efficiency enrichment and separation device for ultra-low concentration gas, including: an air compressor, a mass flow meter, a solenoid valve, an infrared gas analyzer, a vacuum pump, an online collection system, and the like. Advantages of this equipment: double-tower adsorption-desorption system, one tower is adsorbed while the other tower is desorbed; room temperature, normal pressure adsorption, vacuum analysis, easy to achieve reaction conditions, and the possibility of industrialized large-scale production; can be separated and purified below 0.5 % ultra-low concentration gas, effectively solving the problem that less than 1% mine gas cannot be utilized. There are 3 adsorption pipelines connected in series in the adsorption tower, which increases the gas penetration time and improves the adsorption efficiency of the adsorbent; the adsorption tower is equipped with a buffer area, and the adsorption and desorption towers are connected through pipelines to reduce the time spent in the switching process. Among them, the energy consumption of the vacuum pump improves economic efficiency; the multi-stage concentration raising device can meet different working conditions, and can recover low-concentration methane in the product gas, further reducing methane emissions.

Description

A high-efficiency enrichment and separation device for ultra-low concentration gas

technical field

The invention discloses a high-efficiency enrichment and separation device for ultra-low concentration gas, which belongs to the field of resources and energy, and mainly includes: an air compressor, a mass flow meter, a solenoid valve, an infrared gas analyzer, a vacuum pump, an online collection system, and the like.

Background technique

China has abundant reserves of coalbed methane resources. Among the reserves of coalbed methane resources with a buried depth of less than 2000m, the mineable volume is about 36.86 trillion m ³ . -45%, or even lower, the combustion calorific value of coalbed methane with too low concentration is too low and has no economic value for long-distance pipeline transportation. In order to prevent coal mine gas explosions, the past treatment method is to ventilate the mine or carry out gas drainage to keep the mine gas concentration away from the explosive concentration range of 5%-15%. China emits 15 billion m ³ of coalbed methane into the atmosphere every year, mainly containing methane, accounting for about 1/3 of the world's total emissions. The greenhouse effect produced by CH ₄ is 21 times that of CO ₂ . The abnormal climate caused by methane emission into the atmosphere and the damage to the ozone layer have become a major problem faced by the whole world.

Therefore, how to concentrate and utilize methane has become the primary issue in the development of coalbed methane. The development of low-concentration coalbed methane purification technology can not only improve the safety of coal mines and reduce environmental pollution, but also help to solve the problems of irrational energy structure and energy shortage in my country. The pressure swing adsorption method can effectively solve this technical problem. This method can separate and purify low-concentration coal mine gas to obtain high-concentration methane gas. It is an effective and feasible device to solve the problem of mine gas waste. However, the pressure swing adsorption devices currently designed are still in the field of adsorption and purification of mine gas with a concentration of > 1%, and the field of adsorption and purification of gas with a concentration of less than 1% remains to be developed.

The device of the present invention absorbs and purifies 0.1%-5% of the gas, and makes up for the technology and equipment gap that the gas of less than 1% cannot be adsorbed and purified.

Contents of the invention

The purpose of the present invention is to provide a gas separation and adsorption device with an excess concentration of methane gas below 1%, which solves the problems of wasting energy and polluting the environment in the existing mine exhaust air directly discharged into the atmosphere, and achieves resource utilization The effect of using. The design of the S-type adsorption pipeline in series in the present invention can prolong the penetration time and improve the adsorption efficiency of methane; the design of the buffer zone between the two towers is a further improvement of the pressure equalization mode in the existing process, which largely uses The adsorption of purified gas in the adsorption tower is more reasonable and reduces energy consumption; the multi-stage concentration raising device can obtain different concentrations of methane gas according to different requirements, and the setting of the tail gas recovery station device can maximize the use of methane and further increase the methane concentration. Recovery rate. The present invention has reasonable overall structure design, small volume, reduced investment cost and occupied area, can effectively utilize methane in coal mine exhaust air to provide a large amount of clean energy, promote the volume of coal mine ventilation, and promote coal mine safety production.

The technical problem to be solved by the present invention is to provide a pressure swing adsorption tower, which effectively improves the adsorption efficiency of low-concentration gas. The device of the invention can enrich the coal mine gas with concentration lower than 0.5% to high-concentration methane gas with high calorific value and wide application.

A high-efficiency enrichment and separation device for ultra-low concentration gas, the first-stage concentration raising device of the device includes an air compressor 1, a first mass flow meter 2, a second mass flow meter 7, a first buffer tank 3, and a second buffer tank 6. The third buffer tank 11, the first solenoid valve 4a, the second solenoid valve 4b, the third solenoid valve 4c, the fourth solenoid valve 4d, the fifth solenoid valve 4e, the sixth solenoid valve 4f, the seventh solenoid valve 4g, Eighth solenoid valve 4h, vacuum pump 5, first infrared gas analyzer 8a, second infrared gas analyzer 8b, third infrared gas analyzer 8c, first pressure limiting valve 9, second pressure limiting valve 16, check valve 10. Acquisition card 12, computer 13, first stage adsorption tower 14a, first stage analysis tower 14b, rotameter 15, PLC17, first pressure gauge 18a, second pressure gauge 18b, third pressure gauge 18c, fourth pressure gauge Pressure gauge 18d, first liquid quantity display instrument 19a, second liquid quantity display instrument 19b, first drying pipe 20a, second drying pipe 20b, third drying pipe 20c, vacuum display instrument 21, the first stage adsorption tower The first adsorption pipeline 22, the second adsorption pipeline 23, the third adsorption pipeline 24, the first connecting pipeline 25, the first buffer zone A and the ninth electromagnetic valve 26a are set in the first stage of the desorption tower 14a in 14a, and the first stage desorption tower 14b is equipped with the first One analysis pipeline 27, the second analysis pipeline 28, the third analysis pipeline 29, the second connection pipeline 30, the second buffer zone B and the tenth electromagnetic valve 26b; the second stage, the third stage and the fourth stage concentration raising device and The equipment composition and installation location of the first level concentration raising device are the same;

Wherein, the air compressor 1 is connected in series through the first mass flow meter 2 and the first buffer tank 3, and the first buffer tank 3 is respectively connected to the first stage through the second solenoid valve 4b and the fourth solenoid valve 4d. The lower end of the adsorption tower 14a is connected to the first-stage desorption tower 14b; the first buffer tank 3 is connected in series with the gas path formed by the first drying pipe 20a, the second pressure limiting valve 16 and the first infrared gas analyzer 8a; Described first solenoid valve 4a, the 3rd solenoid valve 4c connect the lower end of the first stage adsorption tower 14a and the first stage desorption tower 14b respectively, and link to each other with the second solenoid valve 4b, the 4th solenoid valve 4d; The first stage The middle part of the first-stage adsorption tower 14a and the first-stage desorption tower 14b is connected by the eighth solenoid valve 4h; the first solenoid valve 4a and the third solenoid valve 4c are connected in parallel with each other and connected successively with the vacuum pump 5, the second buffer tank 6, and the second solenoid valve 4c. The second drying pipe 20b, the second mass flow meter 7, and the second infrared gas analyzer 8b are connected; the analysis gas outlet at the end of the second infrared gas analyzer 8b is connected to the raw gas inlet of the second-stage concentration raising device; The analytical gas outlet end of the second-level concentration raising device is connected to the raw material gas inlet of the third-level concentration raising device; the analytical gas outlet end of the third-level concentration raising device is connected to the raw material gas inlet of the fourth-level concentration raising device. The gas port is connected; the upper end of the first stage adsorption tower 14a is connected with the fifth electromagnetic valve 4e and the first pressure gauge 18a; the upper end of the first stage desorption tower 14b is connected with the sixth electromagnetic valve 4f and the second pressure gauge 18b; The first pressure gauge 18a and the second pressure gauge 18b are connected through the seventh solenoid valve 4g; the fifth solenoid valve 4e and the sixth solenoid valve 4f are connected in parallel and connected to the front section of the one-way valve 10; the one-way valve 10 The rear end is connected to the front section of the third buffer tank 11; the third buffer tank 11 is sequentially connected in series with the third drying pipe 20c, the first pressure limiting valve 9, the rotameter 15, and the third infrared gas analyzer 8c; The end product gas outlet of the three infrared gas analyzers 8c is connected to the tail gas recovery device; the tail gas recovery device is connected to the raw material gas inlet end of the first-level concentration raising device; the second-level, third-level and fourth-level concentration improvement The equipment composition and installation location of the device and the first-level concentration raising device are the same.

The first flowmeter 2 of the mass, the second flowmeter 7 are connected with the computer 12; the third pressure gauge 18c and the fourth pressure gauge 18d arranged at the lower end of the first stage adsorption tower 14a and the first stage desorption tower 14b are connected ; The first solenoid valve 4a, the second solenoid valve 4b, the third solenoid valve 4c, the fourth solenoid valve 4d, the fifth solenoid valve 4e, the sixth solenoid valve 4f, the seventh solenoid valve 4g, the eighth solenoid valve 4h , the ninth solenoid valve 26a, and the tenth solenoid valve 26b are connected to the PLC 17; the PLC 17 and the online acquisition card 12 are connected in series to the computer 13.

The internal structure of the first-stage adsorption tower 14a is: it consists of a first adsorption pipeline 22 , a second adsorption pipeline 23 , and a third adsorption pipeline 24 in S-shaped series and a first buffer zone A. Adsorbent activated carbon is placed in the pipeline, the area inside the adsorption tower outside the pipeline is the first buffer zone A, the first buffer zone A is connected to the third adsorption pipeline 24 through the first connecting pipeline 25, and the first connecting pipeline 25 is provided with a second Nine solenoid valves 26a.

The internal structure of the first-stage desorption tower 14b is as follows: it consists of a first desorption pipeline 27 , a second desorption pipeline 28 , and a third desorption pipeline 29 in an S-shaped series of pipelines and a second buffer area B. Adsorbent activated carbon is placed in the pipeline, and the area inside the adsorption tower outside the pipeline is the second buffer zone B. The second buffer zone B is connected to the third analysis pipeline 29 through the second connecting pipeline 30, and the second connecting pipeline 30 is provided with the second Ten solenoid valve 26b.

Furthermore, the ratio of the pipe diameter to the total length of the S-shaped pipes connected in series in the adsorption tower or the desorption tower is 1:4 to 1:12.

Built-in S-type series adsorption tower design parameters

The internal structure of this adsorption tower is shown in Figure 2 and Figure 3, the first adsorption pipeline 22, the second adsorption pipeline 23, the third adsorption pipeline 24 are the adsorption pipelines of S-shaped series connection, adsorbent activated carbon is placed in the pipeline, the first The buffer area A is connected to the third adsorption pipeline 24 through the first connecting pipeline 25, and the ninth electromagnetic valve 26a is arranged in the first connecting pipeline 25; the first analysis pipeline 27, the second analysis pipeline 28, and the third analysis pipeline 29 are S The adsorption pipeline is connected in series, and the activated carbon adsorbent is placed in the pipeline. The second buffer area B is connected with the third analytical pipeline 29 through the second connecting pipeline 30, and the second connecting pipeline 30 is provided with a tenth solenoid valve 26b.

The ratio of the pipe diameter to the total length in the adsorption desorption tower is generally 1:4 to 1:12. The diameter and length of the pipe affect the methane breakthrough time, thereby affecting the methane adsorption efficiency and the final methane recovery efficiency. Therefore, it needs to be determined according to the specific Specific values are selected for the feed gas flow rate and flow rate.

The present invention specifically selects the optimum ratio of pipe diameter and total length in the adsorption desorption tower as 1:9 to design the adsorption tower and desorption tower with a feed gas flow rate of 500 sccm. Therefore, the dimensions of the first adsorption pipeline, the second adsorption pipeline and the third adsorption pipeline in the adsorption tower are Φ80mm×4mm and 240mm long, and the size of the adsorption tower is Φ126mm×10mm and 250mm long; the outer wall of the adsorption pipeline and the inner wall of the adsorption tower The void acts as a buffer zone. Place special barbed wire in the adsorption pipeline and buffer area, fill the adsorption pipeline in the adsorption tower with 250g of activated carbon with a specific surface area of 600-800m ² /g after modification, and fill ^the buffer area with activated carbon 25g; the structural dimensions and fillings of the analytical tower and the adsorption tower are the same.

Compared with the general adsorption tower, the present invention has a built-in S-type series adsorption tower, and the design of the S-shaped pipeline increases the penetration time of the gas in the adsorption tower, which can more fully absorb low-concentration methane gas, and the final gas methane The concentration can reach more than 70%-99%, the highest can reach 99.88%; the recovery efficiency can reach more than 95-99%, the highest can reach 99.99%, which is 5-8% higher than the efficiency of the general adsorption tower, and due to the existence of the buffer area , reduce the energy consumption of the vacuum pump during the switching process, and improve economic efficiency.

The present invention has the following advantages: a double-tower adsorption-desorption system, one tower performs adsorption while the other tower performs desorption; room temperature, normal pressure adsorption, vacuum analysis, reaction conditions are easy to achieve, and there is the possibility of industrialized large-scale production; With an ultra-low concentration of 0.5% gas, it effectively solves the problem that mine gas below 1% cannot be fully utilized.

The difference from other inventions is that there are three adsorption and analysis pipelines connected in series in the adsorption and desorption tower, which increases the gas penetration time and improves the adsorption efficiency of the adsorbent; Connect two adsorption and desorption towers in different working states to reduce the energy consumption of the vacuum pump during the switching process and improve economic efficiency; the multi-stage concentration raising device can meet different working conditions and can recover low concentrations in the product gas methane, further reducing methane emissions.

Description of drawings

Below in conjunction with accompanying drawing, the present invention will be further described.

Fig. 1 is a kind of structural frame diagram of the present invention.

The serial numbers in the figure indicate the first-stage concentration raising device: air compressor 1, first mass flow meter 2, second mass flow meter 7, first buffer tank 3, second buffer tank 6, third buffer tank 11, first Solenoid valve 4a, second solenoid valve 4b, third solenoid valve 4c, fourth solenoid valve 4d, fifth solenoid valve 4e, sixth solenoid valve 4f, seventh solenoid valve 4g, eighth solenoid valve 4h, vacuum pump 5, No. An infrared gas analyzer 8a, a second infrared gas analyzer 8b, a third infrared gas analyzer 8c, a first pressure limiting valve 9, a second pressure limiting valve 16, a one-way valve 10, an acquisition card 12, a computer 13, the first An adsorption tower 14a, a first-stage analytical tower 14b, a rotameter 15, a PLC 17, a first pressure gauge 18a, a second pressure gauge 18b, a third pressure gauge 18c, a fourth pressure gauge 18d, and a first liquid volume indicator 19a , the second liquid volume indicator 19b, the first drying tube 20a, the second drying tube 20b, the third drying tube 20c, and the vacuum indicator 21;

The equipment composition and installation location of the second, third and fourth level concentration raising devices and the first level concentration raising device are the same;

Figure 2a is a top view of the built-in structure of the first-stage adsorption tower

Figure 2b is a top view of the built-in structure of the first-stage analytical tower

22, 23, 24 pipelines are S-shaped adsorption pipelines connected in series, and adsorbent activated carbon is placed in the pipelines. The buffer area A is connected to the adsorption pipeline 24 through a pipeline 25, and the ninth electromagnetic valve 26a is arranged in the pipeline 25; 27, 28, The pipeline 29 is an S-shaped adsorption pipeline connected in series, and activated carbon as an adsorbent is placed in the pipeline, and the buffer area B is connected to the adsorption pipeline 29 through a pipeline 30, and a tenth electromagnetic valve 26b is arranged in the pipeline 30.

Figure 3a is a side view of the built-in pipeline of the first-stage adsorption tower

Figure 3b is a side view of the built-in pipeline of the first-stage analytical tower

The first adsorption pipeline 22, the second adsorption pipeline 23, and the third adsorption pipeline 24 are S-shaped adsorption pipelines connected in series, and adsorbent activated carbon is placed in the pipelines, and the first buffer area A and the third adsorption pipeline 24 pass through the first connecting pipeline. 25 connected, the first connecting pipeline 25 is provided with the ninth solenoid valve 26a; the first analysis pipeline 27, the second analysis pipeline 28, and the third analysis pipeline 29 pipelines are adsorption pipelines in S-shaped series, and adsorbent activity is placed in the pipelines. Carbon, the second buffer area B is connected with the third analysis pipeline 29 through the second connection pipeline 30, and the tenth electromagnetic valve 26b is arranged in the second connection pipeline 30.

Detailed ways

The specific structure of the present invention will be described in detail according to FIG. 1 . The separation and absorption device containing low-concentration methane gas includes a gas distribution device, an air compressor 1, which mixes methane gas with a raw material gas purity of 99.99% and air into a certain concentration of low-concentration methane gas; gas flow control and a buffer drying device. Flow meter 2, second mass flow meter 7, first buffer tank 3, second buffer tank 6, third buffer tank 11, first drying pipe 20a and second drying pipe 20b connected between buffer tank and flow meter , the third drying pipe 20c, through the first mass flow meter 2 to detect and control the amount of gas entering the device of the present invention, through the first buffer tank 3, the second buffer tank 6 and the third buffer tank 11 to limit the gas pressure in the device pipeline , remove the moisture in the gas through the first drying pipe 20a, the second drying pipe 20b, and the third drying pipe 20c, reducing the consumption of subsequent precision instruments; the gas flow control system, the first electromagnetic valve 4a, the second electromagnetic valve 4b, The third solenoid valve 4c, the fourth solenoid valve 4d, the fifth solenoid valve 4e, the sixth solenoid valve 4f, the seventh solenoid valve 4g, the eighth solenoid valve 4h and the one-way valve 10; online collection system, gas concentration online collection card 12, PLC17 and computer 13; the main adsorption analysis device, the first adsorption tower 14a, and the first stage analysis tower 14b.

The experimental device controls the switch of the electromagnetic valve through PLC to realize the continuous cycle of the separation process of methane and nitrogen. After the coal bed gas is boosted by the compressor, it flows into two adsorption towers with activated carbon alternately through the opening and closing of the control valve. When the coal seam gas passes through the adsorption tower, the methane is absorbed by the activated carbon and stays in the adsorption tower, and the remaining gas is discharged from the upper end of the adsorption tower. The flow rate of the exhaust gas is regulated by a rotameter. The analytical gas containing high-concentration methane is drawn out from the lower end of the adsorption tower by vacuuming, and the vacuuming pressure is about 20kPa. The analytical gas flow is measured by a mass flow meter. The cycle timing is realized by Omron PLC controller.

In the two-tower vacuum pressure swing adsorption process, each adsorption tower has to go through five process steps: pressure charging, adsorption, pressure equalization drop, vacuum pumping, and pressure equalization rise. Take the first-stage adsorption tower 14a to perform the adsorption work, and the first-stage desorption tower 14b to perform the analysis work as an example for illustration:

(1) Pressurization: After the first-stage adsorption tower 14a completes the pressure equalization rise, the feed gas enters the first-stage adsorption tower 14a to boost the pressure of the adsorption tower;

(2) Adsorption: After the first-stage adsorption tower 14a completes the pressure boost, the feed gas continues to enter the adsorption tower, and simultaneously opens the exhaust valve on the upper end of the first-stage adsorption tower 14a, and the product gas containing low-concentration methane flows out from the upper end of the adsorption tower;

(3) average pressure drop: when the adsorption of the first stage adsorption tower 14a reaches saturation, the two adsorption towers are connected, and now the pressure of the first stage adsorption tower 14a decreases, and the pressure of the first stage analysis tower 14b increases;

(4) Vacuuming: After the equalizing pressure drop finishes, the first-stage adsorption tower 14a is vacuumed, and at this moment, the pressure of the adsorption tower decreases, and the adsorbed methane gas is resolved from the adsorbent to obtain the analytical gas containing high-concentration methane, And regenerate the adsorbent to prepare for the next adsorption;

(5) Equal pressure rise: After vacuuming, connect the two adsorption towers, and use part of the high-pressure gas in the first-stage desorption tower 14b to boost the pressure of the first-stage adsorption tower 14a.

The specific flow chart will be described in detail by taking the first-stage adsorption tower 14a to perform methane adsorption work and the first-stage desorption tower 14b to perform methane analysis work. After the raw material gas is mixed with air by the air compressor 1 to form low-concentration methane gas, it flows through the first mass flow meter 2 to display the gas flow rate. Most of the gas flows through the first buffer tank 3 and enters the main adsorption analysis device, and a small part flows into The first drying pipe 20a finally enters the first infrared analyzer 8a to analyze the concentration through the second pressure limiting valve 16; at this moment, the second solenoid valve 4b, the third solenoid valve 4c, the fifth solenoid valve 4e, and the seventh solenoid valve 4g are opened, The first electromagnetic valve 4a, the fourth electromagnetic valve 4d, the sixth electromagnetic valve 4f, and the eighth electromagnetic valve 4h are closed, and the gas containing low-concentration methane is adsorbed and purified by the activated carbon adsorbent in the first-stage adsorption tower 14a, and most of the product gas flow The gas pressure is recorded by the first pressure gauge 18a, passes through the fifth electromagnetic valve 4e, passes through the check valve 10 through the buffer third drying pipe 20c, and flows out after the concentration of the product gas is recorded by the third infrared gas analyzer 8c, and a small part of the product gas passes through The sixth electromagnetic valve 4f flows into the first-stage desorption tower 14b, and releases the methane adsorbed by the activated carbon in the first-stage desorption tower 14b as the blowback gas, forming an analysis gas containing high-concentration methane, and the analysis gas flows into the third electromagnetic valve 4c, After passing through the vacuum pump 5, the second buffer tank 6 and the second drying pipe 20b, a small part of the analytical gas flows into the third infrared gas analyzer 8c to record the concentration, and most of the analytical gas is collected by the gas collecting equipment. After the activated carbon adsorption saturation in the first-stage adsorption tower 14a and the activated carbon in the first-stage desorption tower 14b were resolved completely, by automatic switching, the ninth solenoid valve 26a in the first connection pipeline 25, the second solenoid valve in the second connection pipeline 30, etc. The tenth solenoid valve 26b is opened, the third adsorption pipeline 24 and the third analysis pipeline 29 communicate with the first buffer zone A and the second buffer zone B respectively, the eighth solenoid valve 4h is opened, and the first-stage adsorption tower 14a and the first-stage The analytical tower 14b is communicated, and the gas with higher pressure in the first-stage adsorption tower 14a flows through the eighth electromagnetic valve 4h through the first buffer zone A provided in the first-stage adsorption tower 14a and enters the first-stage analytical tower 14b. The second buffer zone B then enters the first-stage desorption tower 14b. After the air pressure is balanced, the ninth electromagnetic valve 26a and the tenth electromagnetic valve 26b built in the first connecting pipeline 25 and the second connecting pipeline 30 are closed, and the third adsorption pipeline 24 , the third analytical pipeline 29 are respectively disconnected from the first buffer area A and the second buffer area B, the eighth electromagnetic valve 4h is closed, the first electromagnetic valve 4a, the fourth electromagnetic valve 4d, the fifth electromagnetic valve 4e, the sixth electromagnetic valve The valve 4f is opened, the second electromagnetic valve 4b, the third electromagnetic valve 4c, and the seventh electromagnetic valve 4g are closed, the first-stage adsorption tower 14a performs methane analysis work, and the first-stage analysis tower 14b performs methane adsorption work, and the cycle works until the next time The cycle begins.

The raised methane gas gradually enters the second, third or even fourth level concentration raising device for further concentration raising. According to the requirements, a 3-4 level concentration raising device is installed, and the tail gas enters the tail gas recovery device. When the methane concentration exceeds 0.1%, The tail gas will be recycled to the first-stage methane cycle device, and methane pressure swing adsorption will be carried out again to improve the methane adsorption efficiency.

In the low-concentration separation and adsorption device adopted by the present invention, the principle of adsorption and concentration is to utilize activated carbon with high specific surface area and well-developed pores _to have different adsorption properties for low-concentration methane and other components such as N and _O at a certain pressure and temperature. The methane in it is separated by adsorption. Since the selected adsorbent - activated carbon has a greater adsorption capacity for methane than N ₂ and O ₂ , methane is adsorbed on the adsorbent, and the product gas from methane removal is discharged from the exhaust port as clean exhaust gas. In a vacuum environment, the saturated activated carbon decomposes methane to form desorption gas, which is collected by the post-installed gas collection device. The adsorption characteristics of activated carbon are also restored during the process of vacuum desorption of methane, ready for the next round of adsorption operation.

The system control mode of the device of the present invention is divided into two types: manual and automatic, and the manual mode is suitable for debugging and maintenance of equipment. The automatic method can not only reduce the problem of simultaneously controlling multiple valves in the pressure swing adsorption process, but also reduce the cumbersome operation, and automatically switch between the adsorption and analysis scenarios of the two towers to improve the automation level. The methane adsorption and separation control device collects all data through the online acquisition card 12, and transmits the electrical signal to the computer 13, and the computer sends instructions to the PLC 17 to automatically control the switches of the solenoid valves and the adsorption and analysis of the two main towers. The control device has the advantages of advanced technology, stable and reliable operation, timely and accurate data collection, timely instruction issuing and execution, durable equipment quality, humanized data collection and control interface design, etc.

In order to ensure the safe and stable operation of the equipment and prevent accidents, the present invention sets the first buffer tank 3, the second buffer tank 6, and the third buffer tank 11 at each control point, especially at the air inlet, before and after separation and adsorption. directional valve 10 and pressure limiting valve 16; when the internal pressure of the device exceeds the preset safety pressure value range of the first pressure gauge 18a and the second pressure gauge 18b, it will automatically alarm and run the safety control program to reduce the internal pressure of the equipment to protect the equipment Safe operation, or directly and automatically cut off the power supply to terminate the reaction. Install methane concentration sensors inside and in key parts of the plant. When methane leaks, the methane concentration sensor can trigger protection devices such as the ventilation system in time, and at the same time give the device an alarm signal to prompt the operator to take corresponding measures.

Detailed ways

Under normal pressure, 25-35°C adsorption, vacuum analysis at 20kPa, and a gas flow rate of 500 sccm, the ratios of adsorption and analysis pipe diameters to total lengths in different adsorption and desorption towers are 1:4, 1:9 and 1:12, adsorption in the desorption tower, the desorption pipeline and the buffer area are filled with activated carbon with a specific surface area of 600-800m ² /g after modification and a specific surface area of 1000-2500m ² /g, for pressure swing adsorption, and According to the actual situation, a 3-4 level concentration raising device is set up to increase the methane concentration step by step.

Specific embodiments 1. Adsorption at normal pressure and 25°C, vacuum analysis at 20kPa, gas flow at 500sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:4, and 1000m ² /g of modified activated carbon is used Under the condition of being used as an adsorbent, the methane concentration of the raw material gas is 0.10%, the methane concentration of the first-stage imported raw material gas is 0.10%, the concentration of the analytical gas flowing out of the first-stage desorption tower is 2.88%, and the product gas flow out of the first-stage adsorption tower The concentration is 0.02%; the methane concentration of the second-stage imported raw material gas is 2.88%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 17.92%, the concentration of the product gas flowing out of the second-stage adsorption tower is 0.21%, and the concentration of the second-stage product gas Enter the exhaust gas recovery device for recovery, and return to the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 17.92%, the concentration of the analytical gas flowing out of the third-stage desorption tower is 47.81%, and the product flowing out of the third-stage adsorption tower The gas concentration is 0.36%. The third-stage product gas enters the exhaust gas recovery device for recovery, and then flows back into the first-stage concentration raising device; the fourth-stage imported raw material gas methane concentration is 47.81%, and the concentration of the analytical gas flowing out of the fourth-stage desorption tower is 78.86%, the concentration of the product gas flowing out of the fourth-stage adsorption tower is 0.43%, the fourth-stage product gas enters the waste gas recovery device for recovery, and returns to the first-stage concentration raising device, and the final concentration of methane discharged into the atmosphere is lower than 0.02%; The recovery efficiency of methane is 95.12%.

Specific embodiment 2. Adsorption at normal pressure and 25°C, vacuum analysis at 20kPa, gas flow at 500 sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:9, and 1000m ² /g of modified activated carbon is used Under the condition of being used as an adsorbent, the methane concentration of the raw material gas is 0.10%, the methane concentration of the first-stage imported raw material gas is 0.10%, the concentration of the analytical gas flowing out of the first-stage desorption tower is 3.12%, and the product gas flow out of the first-stage adsorption tower The concentration is 0.01%; the methane concentration of the second-stage imported raw material gas is 3.12%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 19.26%, the concentration of the product gas flowing out of the second-stage adsorption tower is 0.15%, and the concentration of the second-stage product gas Enter the exhaust gas recovery device for recovery, and return to the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 19.26%, the concentration of the analytical gas flowing out of the third-stage desorption tower is 56.95%, and the product flowing out of the third-stage adsorption tower The gas concentration is 0.27%. The third-stage product gas enters the waste gas recovery device for recovery, and then flows back into the first-stage concentration raising device; the fourth-stage imported raw material gas methane concentration is 56.95%, and the concentration of the analytical gas flowing out of the fourth-stage desorption tower is 82.32%, the concentration of the product gas flowing out of the fourth-stage adsorption tower is 0.38%, the fourth-stage product gas enters the exhaust gas recovery device for recovery, and returns to the first-stage concentration raising device, and the final concentration of methane discharged into the atmosphere is lower than 0.01%; The methane recovery efficiency is 96.56%.

Specific embodiment 3. Adsorption at normal pressure and 25°C, vacuum analysis at 20kPa, gas flow at 500 sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:12, and 1000m ² /g of modified activated carbon is used Under the condition of being used as an adsorbent, the methane concentration of the raw material gas is 0.10%, the methane concentration of the first-stage imported raw material gas is 0.10%, the concentration of the analytic gas flowing out of the first-stage desorption tower is 3.02%, and the product gas flow out of the first-stage adsorption tower The concentration is 0.02%; the methane concentration of the second-stage imported raw material gas is 3.02%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 18.63%, the concentration of the product gas flowing out of the second-stage adsorption tower is 0.19%, and the concentration of the second-stage product gas Enter the exhaust gas recovery device for recovery, and return to the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 18.63%, the concentration of the analytical gas flowing out of the third-stage desorption tower is 51.41%, and the product flowing out of the third-stage adsorption tower The gas concentration is 1.28%. The third-stage product gas enters the exhaust gas recovery device for recovery, and then flows back into the second-stage adsorption tower; the fourth-stage imported raw material gas methane concentration is 51.41%, and the analytical gas concentration of the fourth-stage desorption tower is 79.95%. %, the concentration of the product gas flowing out of the fourth-stage adsorption tower is 0.38%, the fourth-stage product gas enters the waste gas recovery device for recovery, and returns to the first-stage concentration raising device, and the final methane concentration discharged into the atmosphere is lower than 0.02%; methane The recovery efficiency is 95.82%.

Specific embodiment 4. Adsorption at normal pressure and 25°C, vacuum analysis at 15kPa, gas flow at 500sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:4, and 2500m ² /g of modified activated carbon is used Under the conditions used as an adsorbent, the methane concentration of the raw material gas is 0.50%, the methane concentration of the first-stage imported raw material gas is 0.50%, the concentration of the analytical gas flowing out of the first-stage desorption tower is 4.32%, and the concentration of the product gas flowing out of the first-stage adsorption tower is 0.02%; the methane concentration of the second-stage imported raw material gas is 4.32%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 27.66%, the concentration of the product gas flowing out of the second-stage adsorption tower is 0.09%, and the second-stage product gas enters the The exhaust gas recovery device recycles and returns to the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 27.66%, the concentration of the analytical gas flowing out of the third-stage desorption tower is 71.69%, and the product gas outflow of the third-stage adsorption tower The concentration is 0.26%, and the third-stage product gas enters the waste gas recovery device for recovery, and then flows back into the first-stage concentration raising device; the concentration of methane discharged into the atmosphere is lower than 0.02%; the recovery efficiency of methane is 96.44%.

Specific embodiment 5. Adsorption at normal pressure and 25°C, vacuum analysis at a vacuum pressure of 20kPa, gas flow rate of 500sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:9, and 2500m ² /g of modified activated carbon is used Under the conditions used as an adsorbent, the methane concentration of the raw material gas is 0.50%, the methane concentration of the first-stage imported raw material gas is 0.50%, the concentration of the analytical gas flowing out of the first-stage desorption tower is 4.86%, and the concentration of the product gas flowing out of the first-stage adsorption tower is 0.01%; the methane concentration of the second-stage imported raw material gas is 4.86%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 30.42%, the concentration of the product gas flowing out of the second-stage adsorption tower is 0.07%, and the second-stage product gas enters the The exhaust gas recovery device recycles and returns to the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 30.42%, the concentration of the analytical gas flowing out of the third-stage desorption tower is 74.55%, and the product gas outflow of the third-stage adsorption tower The concentration is 0.21%, and the third-stage product gas enters the waste gas recovery device for recovery, and then flows back into the second-stage adsorption tower; the concentration of methane finally discharged into the atmosphere is lower than 0.01%; the recovery efficiency of methane is 97.30%.

Specific embodiment 6. Adsorption at normal pressure and 25°C, vacuum analysis at 20kPa, gas flow at 500sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:12, and 2500m ² /g of modified activated carbon is used Under the conditions used as an adsorbent, the methane concentration of the raw material gas is 0.50%, the methane concentration of the first-stage imported raw material gas is 0.50%, the concentration of the analytical gas flowing out of the first-stage desorption tower is 4.55%, and the concentration of the product gas flowing out of the first-stage adsorption tower is is 0.03%; the methane concentration of the second-stage imported raw material gas is 4.55%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 29.31%, the concentration of the product gas flowing out of the second-stage adsorption tower is 0.08%, and the second-stage product gas enters the The exhaust gas recovery device recycles and returns to the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 29.31%, the concentration of the analytical gas flowing out of the third-stage desorption tower is 72.86%, and the product gas outflow of the third-stage adsorption tower The concentration is 0.23%, and the third-stage product gas enters the waste gas recovery device for recovery, and then flows back into the first-stage concentration raising device; the final methane concentration discharged into the atmosphere is lower than 0.03%; the recovery efficiency of methane is 96.93%.

Specific embodiment 7. Adsorption at normal pressure and 35°C, vacuum analysis at 20kPa, gas flow at 500 sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:4, and 1000m ² /g of modified activated carbon is used Under the condition of being used as an adsorbent, the methane concentration of the raw material gas is 1.00%, the methane concentration of the first-stage imported raw material gas is 1.00%, the concentration of the desorbed gas flowing out of the first-stage desorption tower is 19.12%, and the product gas flow out of the first-stage adsorption tower The concentration is 0.05%; the methane concentration of the second-stage imported raw material gas is 19.12%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 65.23%, the concentration of the product gas flowing out of the second-stage adsorption tower is 0.33%, and the concentration of the second-stage product gas Enter the exhaust gas recovery device for recovery, and return to the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 65.23%, the concentration of the analytical gas flowing out of the third-stage desorption tower is 84.88%, and the product flowing out of the third-stage adsorption tower The gas concentration is 0.41%. The third-stage product gas enters the exhaust gas recovery device for recovery, and then flows back into the second-stage adsorption tower; the final methane concentration discharged into the atmosphere is lower than 0.05%; the methane recovery efficiency is 98.25%.

Specific embodiment 8. Adsorption at normal pressure and 35°C, vacuum analysis at 20kPa, gas flow at 500 sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:9, and 1000m ² /g of modified activated carbon is used Under the condition of being used as an adsorbent, the methane concentration of the raw material gas is 1.00%, the methane concentration of the first-stage imported raw material gas is 1.00%, the concentration of the desorbed gas flowing out of the first-stage desorption tower is 20.32%, and the product gas flowing out of the first-stage adsorption tower The concentration is 0.03%; the concentration of the product gas flowing out of the second-stage adsorption tower is 20.32%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 70.36%, and the concentration of the product gas flowing out of the second-stage adsorption tower is 0.29%. The product gas enters the exhaust gas recovery device for recovery, and returns to the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 70.36%, the concentration of the analytical gas flowing out of the third-stage desorption tower is 86.69%, and the third-stage adsorption tower flows out The concentration of the product gas is 0.35%, the third-stage product gas enters the waste gas recovery device for recovery, and returns to the first-stage concentration raising device; the final methane concentration discharged into the atmosphere is lower than 0.03%; the recovery efficiency of methane is 98.96%.

Specific embodiments 9. Adsorption at normal pressure and 35°C, vacuum analysis at 20kPa, gas flow at 500sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:12, and 1000m ² /g of modified activated carbon is used Under the condition of being used as an adsorbent, the methane concentration of the raw material gas is 1.00%, the methane concentration of the first-stage imported raw material gas is 1.00%, the concentration of the desorbed gas flowing out of the first-stage desorption tower is 18.75%, and the product gas flowing out of the first-stage adsorption tower The concentration is 0.06%; the concentration of the product gas flowing out of the second-stage adsorption tower is 18.75%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 59.85%, and the concentration of the product gas flowing out of the second-stage adsorption tower is 0.35%. The product gas enters the waste gas recovery device for recovery, and flows back into the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 59.85%, the concentration of the desorbed gas flowing out of the third-stage desorption tower is 83.91%, and the outflow of the third-stage adsorption tower The concentration of the product gas is 0.43%, the third-stage product gas enters the waste gas recovery device for recovery, and returns to the first-stage concentration raising device; the final methane concentration discharged into the atmosphere is lower than 0.06%; the recovery efficiency of methane is 97.47%.

Specific embodiments 10. Adsorption at normal pressure and 35°C, vacuum analysis at 20kPa, gas flow at 500 sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:4, and 2500m ² /g of modified activated carbon is used Under the condition of being used as an adsorbent, the methane concentration of the raw material gas is 5.00%, the methane concentration of the first-stage imported raw material gas is 5.00%, the concentration of the analytic gas flowing out of the first-stage desorption tower is 36.52%, and the product gas flow out of the first-stage adsorption tower The concentration is 0.02%; the methane concentration of the second-stage imported raw material gas is 36.52%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 83.38%, the concentration of the product gas flowing out of the second-stage adsorption tower is 0.31%, and the concentration of the second-stage product gas Enter the exhaust gas recovery device for recovery, and return to the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 83.38%, the concentration of the analytical gas flowing out of the third-stage desorption tower is 96.75%, and the product flowing out of the third-stage adsorption tower The gas concentration is 0.40%, and the third-stage product gas enters the waste gas recovery device for recovery, and returns to the first-stage concentration raising device to return to the first-stage concentration raising device; the final concentration of methane discharged into the atmosphere is lower than 0.02%; the recovery of methane The efficiency is 99.36%.

Specific embodiments 11. Adsorption at normal pressure and 35°C, vacuum analysis at 20kPa, gas flow at 500 sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:9, and 2500m ² /g of modified activated carbon is used Under the condition of being used as an adsorbent, the methane concentration of the raw material gas is 5.00%, the methane concentration of the first-stage imported raw material gas is 5.00%, the concentration of the desorbed gas flowing out of the first-stage desorption tower is 39.76%, and the product gas flow out of the first-stage adsorption tower The concentration is 0.01%; the methane concentration of the second-stage imported raw material gas is 39.76%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 87.21%, the concentration of the product gas flowing out of the second-stage adsorption tower is 0.25%, and the concentration of the second-stage product gas Enter the exhaust gas recovery device for recovery, and return to the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 87.21%, the concentration of the analytical gas flowing out of the third-stage desorption tower is 99.88%, and the product flowing out of the third-stage adsorption tower The gas concentration is 0.36%. The third-stage product gas enters the exhaust gas recovery device for recovery, and then flows back into the first-stage concentration raising device; the final methane concentration discharged into the atmosphere is lower than 0.01%; the methane recovery efficiency is 99.99%.

Specific embodiments 12. Adsorption at normal pressure and 35°C, vacuum analysis at 20kPa, gas flow at 500 sccm, adsorption in the adsorption tower, the ratio of the diameter of the analysis pipe to the total length is 1:12, and 2500m ² /g of modified activated carbon is used Under the condition of being used as an adsorbent, the methane concentration of the raw material gas is 5.00%, the methane concentration of the first stage imported raw material gas is 5.00%, the concentration of the analytical gas flowing out of the first stage desorption tower is 35.85%, and the product gas flow out of the first stage adsorption tower The concentration is 0.03%; the methane concentration of the second-stage imported raw material gas is 35.85%, the concentration of the analytical gas flowing out of the second-stage desorption tower is 80.38%, the concentration of the product gas flowing out of the second-stage adsorption tower is 0.34%, and the concentration of the second-stage product gas Enter the exhaust gas recovery device for recovery, and return to the first-stage concentration raising device; the methane concentration of the third-stage imported raw material gas is 80.38%, the concentration of the analytical gas flowing out of the third-stage desorption tower is 94.43%, and the product flowing out of the third-stage adsorption tower The gas concentration is 0.41%. The third-stage product gas enters the exhaust gas recovery device for recovery, and then flows back into the first-stage concentration raising device; the final methane concentration discharged into the atmosphere is lower than 0.03%; the methane recovery efficiency is 99.04%.

Claims (2)

1. A high-efficiency enrichment and separation device for ultra-low concentration gas, characterized in that: the first-stage concentration raising device of the device comprises: an air compressor (1), a first mass flow meter (2), a second mass flow meter ( 7), the first buffer tank (3), the second buffer tank (6), the third buffer tank (11), the first solenoid valve (4a), the second solenoid valve (4b), the third solenoid valve (4c) , the fourth solenoid valve (4d), the fifth solenoid valve (4e), the sixth solenoid valve (4f), the seventh solenoid valve (4g), the eighth solenoid valve (4h), the vacuum pump (5), the first infrared gas Analyzer (8a), second infrared gas analyzer (8b), third infrared gas analyzer (8c), first pressure limiting valve (9), second pressure limiting valve (16), check valve (10) , acquisition card (12), computer (13), first stage adsorption tower (14a), first stage desorption tower (14b), rotameter (15), PLC (17), first pressure gauge (18a), The second pressure gauge (18b), the third pressure gauge (18c), the fourth pressure gauge (18d), the first liquid volume display (19a), the second liquid volume display (19b), the first drying pipe (20a ), the second drying tube (20b), the third drying tube (20c) and vacuum indicator (21); The equipment composition and installation location of the second, third and fourth level concentration raising devices and the first level concentration raising device are the same; The internal structure of the first-stage adsorption tower (14a) is as follows: the first adsorption pipeline (22), the second adsorption pipeline (23), and the third adsorption pipeline (24) are composed of three sections of pipelines in S-shaped series and the first adsorption pipeline. A buffer zone A is composed of; adsorbent activated carbon is placed in the pipeline, and the area inside the adsorption tower outside the pipeline is the first buffer zone A, and the first buffer zone A is connected to the third adsorption pipeline (24) through the first connecting pipeline (25) , the ninth electromagnetic valve (26a) is arranged in the first connection pipeline (25); the internal structure of the first stage desorption tower (14b) is: comprising the first desorption pipeline (27), the second desorption pipeline (28), the The three-section pipeline (29) is an S-shaped pipeline connected in series. Adsorbent activated carbon is placed in the pipeline, and the area inside the adsorption tower outside the pipeline is the second buffer area B, and the second buffer area B is connected to the third analysis pipeline (29 ) are connected by a second connecting pipeline (30), and a tenth electromagnetic valve (26b) is arranged in the second connecting pipeline (30); Wherein, the air compressor (1) is connected in series through the first mass flow meter (2) and the first buffer tank (3), and the first buffer tank (3) is passed through the second solenoid valve (4b), The fourth electromagnetic valve (4d) links to each other with the lower end of the first-stage adsorption tower (14a) and the first-stage desorption tower (14b) respectively; The first surge tank (3) is connected with the first drying pipe (20a), the second The gas path formed by the pressure limiting valve (16) and the first infrared gas analyzer (8a) is connected in series; the first electromagnetic valve (4a) and the third electromagnetic valve (4c) are respectively connected to the first-stage adsorption tower (14a ) and the lower end of the first stage desorption tower (14b), and link to each other with the second solenoid valve (4b), the fourth solenoid valve (4d); the first stage adsorption tower (14a) and the first stage desorption tower (14b ) The middle part of the tower body is connected through the eighth solenoid valve (4h); the first solenoid valve (4a) and the third solenoid valve (4c) are connected in parallel with each other and then connected with the vacuum pump (5), the second buffer tank (6), the first Two drying pipes (20b), the second mass flow meter (7), and the second infrared gas analyzer (8b) are connected; the analysis gas outlet at the end of the second infrared gas analyzer (8b) is connected to the second-stage concentration raising device The raw material gas inlet is connected; the analysis gas outlet of the second-level concentration raising device is connected with the raw material gas inlet of the third-level concentration raising device; the analysis gas outlet of the third-level concentration raising device is connected to the fourth-level concentration raising device. The raw material gas inlet of the first-stage concentration raising device is connected; the upper end of the first-stage adsorption tower (14a) is connected with the fifth solenoid valve (4e) and the first pressure gauge (18a); the first-stage desorption tower (14b) The upper end is connected with the sixth solenoid valve (4f) and the second pressure gauge (18b); the first pressure gauge (18a) and the second pressure gauge (18b) are connected through the seventh solenoid valve (4g), and the fifth The solenoid valve (4e) and the sixth solenoid valve (4f) are connected in parallel to the front section of the one-way valve (10); the rear end of the one-way valve (10) is connected to the front section of the third buffer tank (11); the third The buffer tank (11) is connected in series with the third drying pipe (20c), the first pressure limiting valve (9), the rotameter (15), and the third infrared gas analyzer (8c) in sequence; the third infrared gas analyzer (8c) The end product gas outlet is connected to the tail gas recovery device; the tail gas recovery device is connected to the feed gas inlet end of the first-stage concentration raising device; Described first mass flow meter (2), second flow meter (7) link to each other with computer (13); The 3rd pressure gauge that is arranged in the first stage adsorption tower (14a) and the first stage desorption tower (14b) lower end (18c) is connected with the fourth pressure gauge (18d); the first solenoid valve (4a), the second solenoid valve (4b), the third solenoid valve (4c), the fourth solenoid valve (4d), the fifth solenoid valve Valve (4e), sixth solenoid valve (4f), seventh solenoid valve (4g), eighth solenoid valve (4h), ninth solenoid valve (26a), tenth solenoid valve (26b) are connected to PLC (17) ; The PLC (17) is connected with the computer (13) after being connected in series with the online acquisition card (12). 2. A high-efficiency enrichment and separation device for ultra-low concentration gas according to claim 1, characterized in that the ratio of the pipe diameter to the total length of the S-shaped series pipes in the adsorption tower or the desorption tower is 1:4-1: 12.