CN101920155A - Zero-emission gas drying process and device - Google Patents

Abstract

The invention provides a zero-emission gas drying process and device, which mainly solves the problems of waste and high cost caused by direct discharge of gas in the regeneration tower to pollute the environment or combustion in the process of decompression regeneration in the prior art. The process includes three steps: adsorption, regeneration, and switching. During regeneration, the dried product gas is used as regeneration heating gas and blowing cooling gas. The regeneration of the adsorbent can be completed at a lower heating temperature to obtain a product gas with a low dew point. Regenerating heating air and blowing cold air back to the adsorption process, without any gas being discharged into the atmosphere, is truly "zero emission".

Description

Zero-emission gas drying process and device

technical field

The invention relates to a gas drying process and device, in particular to a zero-emission gas drying process and device.

Background technique

At present, the adsorption-type natural gas dehydration device usually adopts a double-tower structure, and its working principle is: when one tower is performing dehydration and adsorption work, the other tower is performing adsorbent regeneration. The tower for dehydration adsorption uses the adsorbent in the tower to absorb the moisture contained in the raw gas, thereby drying the raw gas; the tower for regeneration of the adsorbent generally directly enters the natural gas used as regeneration gas into the heater and heats it to After the temperature required for regeneration, it enters the tower, flows through the adsorbent bed, heats the adsorbent, and desorbs the moisture adsorbed by the adsorbent, so as to achieve the purpose of adsorbent regeneration.

When the tower for adsorbent regeneration is working, it will continuously discharge regeneration gas. The discharged regeneration gas contains a large amount of water vapor and has a high temperature. The moisture in the wet regeneration gas must be separated. In the closed cycle regeneration process or the open regeneration process, the industry usually adopts air cooling or water cooling to cool the regeneration gas, and then separates the condensed water and other condensed liquids. At present, for compressed air drying, the gas discharged during regeneration is generally directly discharged into the atmosphere, and the combustible gas is directly burned as torch gas.

However, this method has the following disadvantages:

For process gases, natural gas, carbon dioxide, carbon monoxide, hydrogen and toxic and harmful gases, they cannot be discharged directly into the atmosphere, otherwise they will cause harm to the atmosphere and pollute the environment.

When it is directly burned as the torch gas, a large amount of energy is wasted and the cost of the product is increased.

If the exhaust gas is recovered and treated, equipment and capital will be increased; the process of exhaust gas will cause the pressure in the tank to decrease, which will easily cause the pulverization of the adsorbent.

Contents of the invention

The invention provides a zero-emission gas drying process and device to solve the problems of the prior art that the gas in the regeneration tower is directly discharged to pollute the environment or burned to cause waste and high cost during the decompression regeneration process.

Technical solution of the present invention is:

The zero-emission gas drying process includes the following steps:

(1) Adsorption

(1.1) Filtration and separation of the free liquid contained in the raw gas;

(1.2) Introduce pressurized gas gained after step (1.1) to carry out adsorption drying in the tower for adsorption work;

(1.3) filtering the gas obtained after the treatment in step (1.2) to separate the solid dust particles in the gas;

(1.4) Part of the gas obtained after the treatment in step (1.3) is introduced into the gas utilization system, and the other part is introduced into the step (2) for regeneration;

(2) regeneration

(2.1) heating the gas introduced through the step (1.4), so that the temperature rises to the temperature required for the regeneration of the adsorbent to form a high-temperature dry gas;

(2.2) Introduce the high-temperature dry gas into the adsorbent for regeneration, and the high-temperature dry gas heats the adsorbent, decomposes the moisture absorbed in the adsorbent, completes the dehydration regeneration of the adsorbent, and forms high-temperature regenerated moisture at the same time;

(2.3) cooling the high-temperature regenerated moisture-containing gas after step (2.2) to condense the contained water vapor;

(2.4) Carry out gas-liquid separation to the obtained product after step (2.3), pressurize the obtained gas and enter (1) the adsorption link to dry; the obtained free liquid is discharged;

(3) switch

Step (1) adsorption and step (2) regeneration are switched according to the adsorption requirements, and the adsorption is cycled.

The above-mentioned step (3) is switched, and the switch can be switched by a valve; the valve switch can be controlled by a pneumatic actuator or manually.

In the step (2.2) above, the heating of the dry gas can be primary heating or secondary heating.

The above-mentioned adsorbent can be silica gel, aluminum gel or molecular sieve.

The zero-emission gas drying device of the present invention includes a drier 101 composed of drying tanks 1 and 2. The upper and lower ports of the drier 101 communicate with the upper piping system 102 and the lower piping system 103 respectively, and the upper piping system 102 is connected by parallel valves. 3, 4 and parallel valves 5, 6 are formed in parallel, and the connecting pipe 17 of valves 3, 4 communicates with the pre-filter 16 arranged on the intake pipe 21; the lower piping system 103 is composed of parallel valves 7, 8 and Parallel valves 9 and 10 are connected in parallel, and the connecting pipe 27 of the valves 7 and 8 communicates with the post filter 15 arranged on the exhaust pipe 22 through the connecting pipe 18. It is characterized in that: the valves 5 and 6 The connecting pipe 23 communicates with the cooler 13 arranged on the connecting pipe 28, and the gas-liquid separator 14 connected with the connecting pipe 24 is also arranged on the connecting pipe 28; between the pre-filter 16 and the connecting pipe 17 A pressurizing device 12 and a connecting pipe 25 are provided, and the two ends of the connecting pipe 25 communicate with the pre-filter 16 and the pressurizing device 12 respectively; the connecting pipe 24 communicates with the pressurizing device 12; the valves 9, 10 The connection pipe 20 communicates with the heater 11 provided on the connection pipe 19 .

The pressurizing device 12 mentioned above is an injector; the pre-filter 16 can be equipped with a gas-liquid separator or a precision oil removal filter.

The above-mentioned heater 11 may be a primary heating of one heater or a secondary heating of two heaters.

The above-mentioned cooler 13 may be an air-cooled cooler or a water-cooled cooler.

The heater 11 mentioned above may be a plate-fin heat exchanger, a tube-fin heat exchanger, or a shell-and-tube heat exchanger.

The above-mentioned gas-liquid separator 14 can be separated by inertial separation and filtration or a combination of inertia and filtration to form separation.

The advantage that the present invention has is:

1. Zero emission of gas in the regeneration process

The zero-emission gas drying process and device provided by the present invention do not discharge any gas into the atmosphere during the working process, avoiding pollution to the atmospheric environment and waste caused by burning and discharging gas.

2. Reduce costs

The zero-emission gas drying process and device provided by the present invention do not need additional equipment for recovering exhaust gas, reducing capital investment, and the process is simple, easy to operate, and the process of depressurization and boosting after regeneration is omitted, which reduces the cost. .

3. Wide range of application

The zero-emission gas drying process and device provided by the present invention are suitable for dehydration and drying of flammable, explosive, poisonous and harmful gases such as process gas, natural gas, hydrogen, carbon monoxide, and carbon dioxide.

4. Avoid powdering of adsorbent during regeneration

The zero-emission gas drying process and device provided by the invention effectively avoids the pulverization of the adsorbent during the regeneration process.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the present invention.

Details of drawings: 1-drying tank A; 2-drying tank B; 3, 4, 5, 6, 7, 8, 9, 10-valve; 11-heater; 12-ejector; 13-cooler; 14 -gas-liquid separator; 15-post-filter; 16-pre-filter; 17, 18, 19, 20, 23, 24, 25, 27, 28-connecting pipe; 21-intake pipe; 22-exhaust Tube; 101-dryer; 102-upper piping system; 103-lower piping system.

Detailed ways

The zero-emission gas drying process of the present invention comprises the following steps:

(1) Adsorption

(1.1) Filtration and separation of the free liquid contained in the raw gas;

(1.2) Pressurizing the gas obtained after the step (1.1) is introduced into the tower for adsorption and drying; the adsorbent in the adsorption tower can be silica gel, aluminum glue or molecular sieve;

(1.3) filtering the gas obtained after the treatment in step (1.2) to separate the solid dust particles in the gas;

(1.4) Part of the gas obtained after the treatment in step (1.3) is introduced into the gas utilization system, and the other part is introduced into the step (2) for regeneration;

(2) regeneration

(2.1) Heating the gas introduced through step (1.4), can choose primary heating or secondary heating, so that the temperature rises to the temperature required by the regeneration of the adsorbent to form a high-temperature dry gas;

(2.2) Introduce the high-temperature dry gas into the adsorbent for regeneration, and the high-temperature dry gas heats the adsorbent, decomposes the moisture absorbed in the adsorbent, completes the dehydration regeneration of the adsorbent, and forms high-temperature regenerated moisture at the same time;

(2.3) cooling the high-temperature regenerated moisture-containing gas after step (2.2) to condense the contained water vapor;

(2.4) Carry out gas-liquid separation to the obtained product after step (2.3), pressurize the obtained gas and enter (1) the adsorption link to dry; the obtained free liquid is discharged;

(3) switch

Step (1) adsorption and step (2) regeneration are switched according to the adsorption requirements, and the adsorption is cycled. Switching can be done through valves, and valve switching can be controlled by pneumatic actuators or manually.

In this drying process, the dried product gas is used as regeneration heating gas and blowing cooling gas during regeneration, and the regeneration of the adsorbent can be completed at a lower heating temperature to obtain a product gas with a low dew point. Regenerating heating air and blowing cold air back to the adsorption process, without any gas being discharged into the atmosphere, is truly "zero emission".

Below in conjunction with accompanying drawing, device of the present invention is described in detail, as shown in Figure 1:

The zero-emission gas drying device includes a dryer 101 composed of a drying tank 1 and a drying tank 2. The upper and lower ports of the dryer 101 communicate with the upper piping system 102 and the lower piping system 103 respectively. The upper piping system 102 is connected by a parallel valve 3 , valve 4 and parallel valve 5, valve 6 are connected in parallel, the connecting pipe 17 of valve 3 and valve 4 communicates with the pre-filter 16 arranged on the intake pipe 17; the lower piping system 103 is composed of parallel valve 7, valve 8 It is formed in parallel with valve 9 and valve 10 connected in parallel, the connecting pipe 27 of valve 7 and valve 8 communicates with the post filter 15 arranged on the exhaust pipe 22 through connecting pipe 18, and the connecting pipe 23 of valve 5 and valve 6 communicates with The cooler 13 that is arranged on the connecting pipe 28 communicates, and the gas-liquid separator 14 that is connected with the connecting pipe 24 is also arranged on the connecting pipe 28; Pipe 25, the two ends of connecting pipe 25 communicate with pre-filter 16 and pressurizing device 12 respectively; Connecting pipe 24 communicates with pressurizing device 12; The heater 11 communicates.

When drying tank 1 is performing adsorption work and drying tank 2 is performing regeneration:

Adsorption work: the wet gas enters the pre-filter 16 from the intake pipe 21, and after separating the free water in the gas, it enters the top of the drying tank 1 through the connecting pipe 25, injector 12, connecting pipe 17, and valve 3 in turn, and automatically Through the adsorbent bed from top to bottom, the moisture in the gas is absorbed, and the dry gas is discharged from the bottom of the drying tank, and enters the post-filter 15 through the valve 7, the connecting pipe 27, and the connecting pipe 18 to remove the dust particles in the gas. , enter the exhaust pipe 22 and be sent to the gas consumption point. During the adsorption process, the valves 4, 5, 8 and 9 are closed.

Regeneration work: Part of the dry gas is led out from the connecting pipe 27, and enters the heater 11 through the connecting pipe 19 to be heated up, then enters the bottom of the drying tank 2 through the connecting pipe 20 and the valve 10, and the hot air flows through the adsorbent bed from bottom to top layer, heats the adsorbent and takes away the resolved water vapor, which is discharged from the top of the tank and enters the cooler 13 through the valve 6 and the connecting pipe 23. After the gas is cooled, the water vapor in the gas is separated through the connecting pipe 28 and the separator 14. The condensed water enters the ejector 12 through the connecting pipe 24, and enters the adsorption tank 1 together after being merged with the airflow from the connecting pipe 25. After reaching the preset regeneration heating temperature, the heater 11 stops working, that is, it enters the regeneration blowing cooling stage until the regeneration process ends. After the regeneration process ends, it marks the end of a working cycle, and the two drying tanks are switched. At this time, the drying tank 2 performs adsorption , while the drying tank 1 enters the regeneration process.

The pre-filter 16 of the present invention can add a first-stage gas-liquid separator or precision oil removal filter according to the temperament of the gas to be dried, that is, according to the formula of "gas-liquid separator + pre-filter + precision oil removal filter" The heater 11 can adopt one heater for primary heating or two heaters for secondary heating; the cooler 13 can be air-cooled or water-cooled, and the heat exchanger can be plate-fin, tube-fin or shell-and-tube ; Separator 14 can be separated by inertial separation and filtration or a combination of inertia and filtration to form separation.

Claims (10)

1. a drying gas in order to achieve zero release technology is characterized in that, may further comprise the steps:

(1) absorption

(1.1) contained free fluid in the unstrpped gas is carried out isolated by filtration;

(1.2) will after handling, step (1.1) the gained gas pressurized introduce adsorption dry in the tower that adsorbs work;

(1.3) will after handling, step (1.2) filter the solid dust particle in the divided gas flow by gained gas;

(1.4) will a gained gas part introduce the gas system that uses after step (1.3) is handled, another part is introduced step (2) regeneration;

(2) regeneration

(2.1) gas of introducing through step (1.4) is heated, make temperature rise to the temperature of adsorbent reactivation requirement, form high temperature drying gas;

(2.2) high temperature drying gas is introduced in the adsorbent of regenerating, high temperature drying gas heats adsorbent, and moisture adsorbed in the adsorbent is resolved, and finishes the dehydration regeneration to adsorbent, forms high temperature regeneration simultaneously and contains moisture;

(2.3) high temperature regeneration after handling through step (2.2) is contained moisture and cool off, make its moisture vapor condensation;

(2.4) gains after handling through step (2.3) are carried out gas-liquid separation, enter (1) absorption link after the gas pressurized that obtains and carry out drying; The free fluid that obtains is discharged;

(3) switch

Step (1) absorption and step (2) regeneration require to switch according to absorption, circulation absorption.

2. according to the described drying gas in order to achieve zero release technology of claim 1, it is characterized in that: described step (3) is switched, and described switching is to switch by valve; It is to start actuator control to switch or switch manually that described valve switches.

3. according to claim 1 or 2 described drying gas in order to achieve zero release technologies, it is characterized in that: described step (2.1) is one-level heating or secondary heating to the heating of dry gas.

4. according to the described gas heat exchange of claim 3 drying process, it is characterized in that: described adsorbent is silica gel, aluminium glue or molecular sieve.

5. drying gas in order to achieve zero release device, comprise the drier (101) that constitutes by drying chamber (1), (2), the upper and lower port of described drier (101) reaches down with last piping (102) respectively, and piping (103) is communicated with, described valve (3), (4) and valve (5), (6) formation in parallel in parallel that goes up piping (102) by parallel connection, the tube connector (17) of described valve (3), (4) is communicated with fore filter (16) on being arranged at air inlet pipe (21); Described piping (103) down is by valve (7), (8) and valve (9), (10) formation in parallel in parallel of parallel connection, the tube connector (27) of described valve (7), (8) is communicated with by tube connector (18) with post-filter (15) on being arranged at blast pipe (22), it is characterized in that: the tube connector (23) of described valve (5), (6) is communicated with cooler (13) on being arranged at tube connector (28), also is provided with the gas-liquid separator (14) that is connected with tube connector (24) on the described tube connector (28); Be provided with pressue device (12) and tube connector (25) between described fore filter (16) and the tube connector (17), the two ends of tube connector (25) are communicated with fore filter (16) and pressue device (12) respectively; Described tube connector (24) is communicated with pressue device (12); The tube connector (20) of described valve (9), (10) is communicated with heater (11) on being arranged at tube connector (19).

6. drying gas in order to achieve zero release device according to claim 5 is characterized in that: described pressue device (12) is an injector; Described fore filter (16) configuration gas-liquid separator or accurate oil removal filter.

7. according to claim 5 or 6 described drying gas in order to achieve zero release devices, it is characterized in that: described heater (11) is the one-level heating of a heater or the secondary heating of two heaters.

8. gas heat exchange drying device according to claim 7 is characterized in that: described cooler (13) is air-cooled cooler or water-cooled cooler.

9. drying gas in order to achieve zero release device according to claim 8 is characterized in that: described heater (11) is plate-fin heat exchanger, fin-tube type heat exchanger or shell-and-tube heat exchanger.

10. drying gas in order to achieve zero release device according to claim 9 is characterized in that: described gas-liquid separator (14) is that inertial separation isolated by filtration or inertia are combined to form with filtration and separate.