CN110394026A - Large scale pressure swing adsorption cascade air separation unit - Google Patents

Abstract

The present invention provides a kind of extensive pressure-variable adsorption step air-separating plant.Air pressurized fan outlet is connected by dehydration carbon dioxide removal adsorption tower with the entrance of radial zeolite molecular sieve pressure-swing absorber group, and tower group entrance is respectively arranged with sequencing valve, and is connected to drawdown pump in the entrance of radial zeolite molecular sieve pressure-swing absorber group；The outlet of radial zeolite molecular sieve pressure-swing absorber group is connected by sequencing valve with the entrance of carbon molecular sieve pressure-swing absorber group, and the outlet of tower group is connected to drawdown pump；Pressure-swing absorber group realizes that part adsorption tower adsorbing separation, partial adsorbates tower desorption and regeneration are recycled by sequencing valve.

Description

Large scale pressure swing adsorption cascade air separation unit

1. Technical field

The invention provides a large-scale pressure swing adsorption cascade air separation device, which belongs to the technical field of air separation.

2. Background technology

The production of modern coal chemical industry, metallurgical industry, petroleum refining and sulfuric acid industry needs to consume a lot of oxygen, but the demand for nitrogen is small. Among the existing oxygen production methods, the air separation method is the most economical industrial oxygen production method. At present, in the field of air separation, cryogenic rectification (cryogenic separation) is a traditional oxygen production method, and pressure swing adsorption and membrane separation are emerging oxygen production methods. The cryogenic rectification method is mature, suitable for large-scale production of high-pressure oxygen and high-pressure nitrogen, can obtain high-purity oxygen and nitrogen, and has a high recovery rate, but the production ratio of oxygen and nitrogen is too small, only 21:78 (volume ratio ), it is difficult to meet the needs of industrial processes with high oxygen consumption and low nitrogen consumption. The pressure swing adsorption method is relatively mature, suitable for small and medium-scale production of oxygen, can obtain low-pressure oxygen of medium purity, and discharge nitrogen at low pressure, but the inert gases such as argon, helium and neon cannot be separated, which affects the further improvement of oxygen purity and The recovery rate needs to be improved. Membrane separation technology is being developed, suitable for small and ultra-small scale production of oxygen, capable of obtaining low-concentration oxygen, high investment and no separation membrane for large-scale industrial application.

However, for the production processes such as coal oxygen-enriched combustion, semi-coke oxythermal method to produce acetylene, metal oxythermal reduction smelting, heavy oil pyrolysis gasification coupling, and sulfuric acid industry, a large amount of low-pressure oxygen is consumed, while the demand for nitrogen is small. The investment and energy consumption of cryogenic separation is too large and the potential energy of oxygen pressure is lost. It is urgent to develop large-scale pressure swing adsorption air separation technology and equipment to meet the modern industry's demand for low-pressure high-purity oxygen.

3. Contents of the invention

In order to overcome the deficiencies in the existing air pressure swing adsorption separation technology, the purpose of the invention is to develop a large-scale pressure swing adsorption cascade air separation device, which can greatly improve the scale of air pressure swing adsorption separation and the purity of oxygen, Reduce the energy consumption of high-purity oxygen production, the investment in large-scale oxygen production and the amount of metal materials used.

The device adopted in the present invention utilizes the radial pressure swing adsorption tower to greatly increase the scale of air pressure swing adsorption separation, reduces the energy consumption of high-purity oxygen separation, and selectively adsorbs nitrogen and carbon molecular sieve pressure swing through the zeolite molecular sieve pressure swing adsorption tower group. The combined measure of selective adsorption of oxygen by the adsorption tower group greatly reduces the content of inert gases such as argon, helium and neon in oxygen, thereby improving the purity and recovery rate of oxygen, and at the same time can obtain high-purity nitrogen, thereby Realized large-scale, low-pressure, high-purity, low-energy cascade pressure swing adsorption separation of air.

The large-scale pressure swing adsorption cascade air separation device of the present invention is characterized in that: the outlet of the air pressurizing fan is connected to the inlet of the radial zeolite molecular sieve pressure swing adsorption tower group through the dehydration and carbon dioxide adsorption tower, and the inlet and outlet of the tower group are equipped with program-controlled valves, and A decompression pump is connected to the inlet of the radial zeolite molecular sieve pressure swing adsorption tower group; the outlet of the radial zeolite molecular sieve pressure swing adsorption tower group is connected to the inlet of the carbon molecular sieve pressure swing adsorption tower group through a program-controlled valve, and the outlet of the tower group is connected with The decompression pump; the pressure swing adsorption tower group realizes the adsorption and separation of part of the adsorption tower and the desorption and regeneration of part of the adsorption tower through the program-controlled valve.

In the present invention, the zeolite molecular sieve loaded in the radial zeolite molecular sieve PSA tower group is one of 5A molecular sieve, lithium X molecular sieve, lithium A molecular sieve, 13X molecular sieve and alkaline earth metal modified molecular sieve.

In the present invention, the pressure swing adsorption separation device is operated by vacuum pressure swing adsorption or low pressure swing adsorption.

In the present invention, the carbon molecular sieve PSA tower is a radial PSA tower or an axial PSA tower.

In the present invention, the radial pressure swing adsorption tower is arranged in concentric circles from the outside to the inside by the tower wall, the isolation cylinder and the central pipe. The upper part of the air chamber is sealed with the isolation cylinder, the isolation cylinder and the isolation cylinder form an auxiliary adsorption chamber, the isolation cylinder and the central pipe form an adsorption chamber, and the inner bottom of the central pipe is equipped with an anti-dead zone guiding cone; the bottom side of the tower wall is connected to the tangential air intake The central pipe connected to the outlet of the adsorption tail gas is arranged on the top of the tower; the tower wall, central pipe and isolation cylinder are sealed and connected with the bottom plate; the auxiliary adsorption chamber and the bottom of the adsorption chamber are respectively equipped with an auxiliary adsorbent discharge port and an adsorbent discharge port.

In the present invention, the concentration of oxygen-enriched air obtained by separating the air radially through the zeolite molecular sieve pressure swing adsorption tower group is 50%-85%.

4. Description of drawings

Figure 1 is a schematic diagram of the device of the present invention.

Explanation of reference signs

1. Fan, 2. Dehydration and carbon dioxide pre-adsorption tower, 3. Radial zeolite molecular sieve pressure swing adsorption tower, 4. Decompression pump, 5. Carbon molecular sieve pressure swing adsorption tower, 6. Program-controlled valve.

The characteristics of the device of the present invention will be described in detail below in conjunction with FIG. 1 and the embodiments.

5. Specific implementation

The following examples are all in accordance with the large-scale pressure swing adsorption cascade air separation device shown in Fig. 1 . The process described in Figure 1 specifically includes:

After the filtered air is pressurized by the fan 1 and pretreated by the dehydration and decarbonation adsorption tower 2, the dry and decarbonated pressurized air first passes through the radial zeolite molecular sieve pressure swing adsorption tower 3 for adsorption and separation, nitrogen is adsorbed by the zeolite molecular sieve, Oxygen-enriched air flows out of the zeolite molecular sieve pressure swing adsorption tower 3; the zeolite molecular sieve pressure swing adsorption tower 3 is switched through the program-controlled valve 6, and the high-purity nitrogen is decompressed and desorbed from the zeolite molecular sieve pressure swing adsorption tower 3 by the decompression pump 4 as a product for delivery Or outflow, zeolite molecular sieve pressure swing adsorption tower 3 recycling. The oxygen-enriched air flowing out of the zeolite molecular sieve pressure swing adsorption tower 3 enters the carbon molecular sieve pressure swing adsorption tower 5, the oxygen is absorbed by the carbon molecular sieve, and the residual nitrogen, argon and helium, etc. flow out of the carbon molecular sieve pressure swing adsorption tower 5 and are discharged; through the program-controlled valve 6 Switch the carbon molecular sieve pressure swing adsorption tower 5, high-purity oxygen is decompressed and desorbed from the carbon molecular sieve pressure swing adsorption tower 5 by the decompression pump 4 and sent out as a product, and the carbon molecular sieve pressure swing adsorption tower 5 is recycled. The pressure swing adsorption tower group realizes the adsorption and separation of part of the adsorption tower and the desorption and regeneration of part of the adsorption tower through the program-controlled valve.

The zeolite molecular sieve filled in the radial zeolite molecular sieve PSA tower group is one of 5A molecular sieve, lithium X molecular sieve, lithium A molecular sieve, 13X molecular sieve and alkaline earth metal modified molecular sieve.

The pressure swing adsorption separation device is operated by vacuum pressure swing adsorption or low pressure swing adsorption.

The carbon molecular sieve PSA tower is a radial PSA tower or an axial PSA tower.

The radial pressure swing adsorption tower is arranged in concentric circles from the outside to the inside by the tower wall, the isolation cylinder and the center pipe. The upper part of the cylinder forms a sealed air chamber, the isolation cylinder and the isolation cylinder form an auxiliary adsorption chamber, the isolation cylinder and the central tube form an adsorption chamber, and the inner bottom of the central tube is provided with an anti-dead zone guiding cone; the bottom side of the tower wall is connected to a tangential air inlet, The central pipe connecting the outlet of the adsorption tail gas is arranged at the top of the tower; the tower wall, the central pipe and the isolation cylinder are sealed and connected with the bottom plate; the auxiliary adsorption chamber and the bottom of the adsorption chamber are respectively equipped with an auxiliary adsorbent discharge port and an adsorbent discharge port.

The concentration of the oxygen-enriched air obtained by separating the air radially through the zeolite molecular sieve pressure swing adsorption tower group is 50%-85%.

Example 1

The zeolite molecular sieve treated in this embodiment is a lithium A molecular sieve, the pressure swing adsorption separation device is a vacuum pressure swing adsorption, and the carbon molecular sieve pressure swing adsorption tower is a radial pressure swing adsorption tower:

The process is as follows:

After the filtered air is pressurized by the fan 1 and pretreated by the dehydration and decarbonation adsorption tower 2, the dry and decarbonated pressurized air is first adsorbed and separated by the radial zeolite molecular sieve vacuum pressure swing adsorption tower 3, and the nitrogen is absorbed by the lithium A type Molecular sieve adsorption, 70% of the oxygen-enriched air flows out of the zeolite molecular sieve vacuum pressure swing adsorption tower 3; through the program control valve 6, the zeolite molecular sieve vacuum pressure swing adsorption tower 3 is switched, and the high-purity nitrogen is reduced from the zeolite molecular sieve pressure swing adsorption tower 3 by the decompression pump 4 Compressed and desorbed as a product for delivery, the zeolite molecular sieve vacuum pressure swing adsorption tower 3 is recycled; the 70% oxygen-enriched air flowing out of the zeolite molecular sieve vacuum pressure swing adsorption tower 3 enters the radial carbon molecular sieve vacuum pressure swing adsorption tower 5, and the oxygen is absorbed by the carbon molecular sieve Adsorption, residual nitrogen, argon, helium, etc. flow out of the radial carbon molecular sieve vacuum pressure swing adsorption tower 5; through the program control valve 6, the carbon radial molecular sieve vacuum pressure swing adsorption tower 5 is switched, and the high-purity oxygen is pumped from the vacuum pump 4 The radial carbon molecular sieve vacuum pressure swing adsorption tower 5 decompresses and desorbs it as a product to be sent out. The vacuum pressure swing adsorption tower 5 of the radial carbon molecular sieve is recycled. The pressure swing adsorption tower group realizes the adsorption separation of part of the adsorption tower and the desorption regeneration of part of the adsorption tower through the program-controlled valve.

The results show that the oxygen purity in the process of Example 1 reaches 99.95%, and the recovery rate is greater than 95%; the nitrogen purity is 95%, and the recovery rate is 85%; the energy consumption of oxygen separation in the low temperature rectification method is reduced by 35%.

Example 2

The zeolite molecular sieve treated in this embodiment is a 5A molecular sieve, the pressure swing adsorption separation device is a low pressure swing adsorption, and the carbon molecular sieve pressure swing adsorption tower is an axial pressure swing adsorption tower:

The process is as follows:

After the filtered air is pressurized by the fan 1 and pretreated by the dehydration and decarbonation adsorption tower 2, the dry and decarbonated pressurized air first passes through the radial zeolite molecular sieve low-pressure pressure swing adsorption tower 3 for adsorption and separation, and the nitrogen is absorbed by the 5A molecular sieve Adsorption, 65% of the oxygen-enriched air flows out of the zeolite molecular sieve low pressure swing adsorption tower 3; the zeolite molecular sieve low pressure swing adsorption tower 3 is switched by the program control valve 6, and the high-purity nitrogen is decompressed from the zeolite molecular sieve pressure swing adsorption tower 3 by the decompression pump 4 The desorbed product is sent out, and the zeolite molecular sieve low pressure swing adsorption tower 3 is recycled; the 65% oxygen-enriched air flowing out of the zeolite molecular sieve low pressure swing adsorption tower 3 enters the radial carbon molecular sieve low pressure swing adsorption tower 5, and oxygen is absorbed by the carbon molecular sieve , the residual nitrogen, argon and helium flow out of the axial carbon molecular sieve low-pressure pressure swing adsorption tower 5 and are discharged; the carbon axial molecular sieve low-pressure pressure swing adsorption tower 5 is switched through the program-controlled valve 6, and the high-purity oxygen is pumped from the diameter by the pressure-reducing pump 4 The carbon molecular sieve vacuum pressure swing adsorption tower 5 is decompressed and desorbed as a product, and the vacuum desorption is sent as a product, and the axial carbon molecular sieve low-pressure pressure swing adsorption tower 5 is recycled. The pressure swing adsorption tower group realizes the adsorption separation of part of the adsorption tower and the desorption regeneration of part of the adsorption tower through the program-controlled valve.

The results show that the oxygen purity in the process of Example 1 reaches 99%, and the recovery rate is greater than 95%; the nitrogen purity is 93%, and the recovery rate is 80%; the energy consumption of oxygen separation is reduced by 25% compared with the cryogenic rectification method.

The large-scale pressure swing adsorption cascade air separation device provided by the present invention doubles the processing capacity of the pressure swing adsorption air separation by using the radial pressure swing adsorption tower, which can reach more than 30000m ³ /h, reaching the performance of low temperature rectification air separation Processing capacity; the combined measure of selectively adsorbing nitrogen through the zeolite molecular sieve pressure swing adsorption tower, and then selectively adsorbing oxygen through the carbon molecular sieve pressure swing adsorption tower greatly improves the oxygen purity of the pressure swing adsorption air separation and reduces the argon in oxygen The content of inert gases such as , helium and neon has achieved the separation effect of cryogenic rectification air separation, but the energy consumption of high-purity oxygen separation has been reduced by more than 25% in cryogenic rectification air separation, thus realizing large-scale, low-pressure, high-purity air , Low energy consumption pressure swing adsorption cascade separation.

Claims (6)

1. The large-scale pressure swing adsorption cascade air separation device is characterized in that the outlet of the air pressurizing fan is connected to the inlet of the radial zeolite molecular sieve pressure swing adsorption tower group through the dehydration and decarbonation adsorption tower, and the inlet and outlet of the tower group are equipped with program-controlled valves. A decompression pump is connected to the inlet of the radial zeolite molecular sieve pressure swing adsorption tower group; the outlet of the radial zeolite molecular sieve pressure swing adsorption tower group is connected to the inlet of the pressure swing adsorption tower group through a program-controlled valve carbon molecular sieve, and the outlet of the tower group is connected to the inlet of the pressure swing adsorption tower group. There is a decompression pump; the pressure swing adsorption tower group realizes the adsorption and separation of part of the adsorption tower and the desorption and regeneration of part of the adsorption tower through the program-controlled valve. 2. The large-scale pressure swing adsorption cascade air separation device according to claim 1, wherein the zeolite molecular sieve packed in the radial zeolite molecular sieve pressure swing adsorption tower group is 5A molecular sieve, lithium X type molecular sieve, lithium A type molecular sieve , 13X molecular sieve and one of alkaline earth metal modified molecular sieves. 3. The large-scale pressure swing adsorption cascade air separation device according to claim 1, characterized in that the pressure swing adsorption separation device is operated by vacuum pressure swing adsorption or low pressure swing adsorption. 4. The large-scale pressure swing adsorption cascade air separation device according to claim 1, wherein the carbon molecular sieve pressure swing adsorption tower is a radial pressure swing adsorption tower or an axial pressure swing adsorption tower. 5. The large-scale pressure swing adsorption cascade air separation device according to claim 1, wherein the radial pressure swing adsorption tower is arranged in concentric circles from the outside to the inside by the tower wall, the isolation cylinder and the center pipe, and the isolation cylinder and The top of the central tube is closed by the adsorbent compression plate to form the upper part of the adsorption section; the tower wall and the isolation cylinder form an upper sealed air chamber, the isolation cylinder and the isolation cylinder form an auxiliary adsorption chamber, and the isolation cylinder and the central tube form an adsorption chamber. The anti-dead zone guide cone is installed at the bottom; the bottom side of the tower wall is connected to the tangential air inlet, and the central pipe connected to the outlet of the adsorption exhaust gas is arranged on the top of the tower; the tower wall, the central pipe and the isolation cylinder are sealed and connected with the bottom plate; the auxiliary adsorption chamber and the adsorption chamber An auxiliary adsorbent discharge port and an adsorbent discharge port are respectively installed at the bottom. 6. The large-scale pressure swing adsorption cascade air separation device according to claim 1, characterized in that the concentration of oxygen-enriched air obtained by separating the air radially from the zeolite molecular sieve pressure swing adsorption tower group is 50%-85%.