Gas separation method and device

• US 6,923,844 B2
• Filed: 11/21/2002
• Issued: 08/02/2005
• Est. Priority Date: 11/27/2001
• Status: Expired due to Term

• Current Assignee: Taiyo Nippon Sanso Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: Taiyo Nippon Sanso Corporation (Mitsubishi Chemical Group Corp.)
• Inventors: Kawai, Masato, Nakamura, Akihiro, Urakami, Tatsushi, Nagasaka, Tooru
• Primary Examiner(s): Spitzer, Robert H.
• Application Number:
  US10/495,630
• Publication Number:
  US 20050000355A1
• Time in Patent Office: 985 Days
• Field of Search: 95/8, 95/12, 95/19, 95/22, 95 96-106, 951/27, 951/30, 961/11, 961/13, 961/14, 961/30, 961/33, 961/43, 961/44
• US Class Current: 95/12
• CPC Class Codes: B01D 2253/102 Carbon
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2253/308 Pore size
• CPC Class Codes: B01D 2256/10 Nitrogen
• CPC Class Codes: B01D 2256/18 Noble gases
• CPC Class Codes: B01D 2257/102 Nitrogen
• CPC Class Codes: B01D 2257/11 Noble gases
• CPC Class Codes: B01D 2258/0216 from CVD treatment or semi-conductor manufacturing
• CPC Class Codes: B01D 2259/40007 Controlling pressure or temperature swing adsorption
• CPC Class Codes: B01D 2259/40052 Recycled product or process gas
• CPC Class Codes: B01D 2259/40081 Counter-current
• CPC Class Codes: B01D 2259/402 using two beds
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: B01D 53/053 with storage or buffer vessel

Abstract

A gas separation method and apparatus that recovers efficiently principal gas components from a feed gas that includes a plurality of components, and enables supplying the product gases continuously at a stable flow rate and component concentration. A first separation step using a first adsorption column and a second separation step using a second adsorption column are provided, a circulating feed gas, consisting of the recovered exhaust gases discharged in each of the steps and the feed gas, is used as a gas to be separated. The outflow rate and component concentration of a second gas product are maintained constant by controlling the outflow rate of the first gas product.

Claims

1. A gas separation method in which principal gas components are separated from a feed gas that includes at least a first gas component and a second gas component using a pressure swing adsorption method, comprising:

a first separation step in which the first gas component is separated as a first gas product by using a first adsorbent that hardly adsorbs the first gas component and easily adsorbs the second gas component; and

a second separation step in which the second gas component is separated as a second gas product by using a second adsorbent that easily adsorbs the first gas component and hardly adsorbs the second gas component;

wherein

in the first and second separation step, a circulating feed gas is used as the gas to be separated, where the circulating feed gas consists of recovered discharge gases that are discharged when the adsorbents are regenerated and the feed gas; and

based on at least one of the component concentration in the circulating feed gas and the pressure of the gas delivery path, the second gas product is extracted at a constant outflow rate and component concentration by controlling the outflow rate of the first gas product.

4. A gas separation method according to any one of the claims 1 to 3, wherein the first gas component of the feed gas is nitrogen and the second gas component of the feed gas is krypton or xenon.

5. A gas separation method according to claim 4, wherein the first adsorbent that fills the first adsorption column is activated carbon, and the second adsorbent that fills the second adsorption column is an adsorbent that can separate krypton or xenon from a mixed gas consisting of krypton or xenon and nitrogen by using the difference in adsorption rates between nitrogen and krypton or xenon.

6. A gas separation step according to claim 5, wherein the pore diameter of the second adsorbent that fills the second adsorption column is approximately 0.4 nm.

7. A gas separation method according to any one of the claims 1 to 3, wherein the first adsorbent that fills the first adsorption column is activated carbon, and the second adsorbent that fills the second adsorption column is an adsorbent that can separate krypton or xenon from a mixed gas consisting of krypton or xenon and nitrogen by using the difference in adsorption rates between nitrogen and krypton or xenon.

8. A gas separation step according to claim 7, wherein the pore diameter of the second adsorbent that fills the second adsorption column is approximately 0.4 nm.

2. A gas separation method in which principal gas components are separated from a feed gas that includes at least a first gas component and a second gas component using a pressure swing adsorption method comprising:

a first separation step in which the first gas component is separated as a first gas product by using a first adsorbent that hardly adsorbs the first gas component and easily adsorbs the second gas component; and

a second separation step in which the second gas component is separated as a second gas product by using a second adsorbent that easily adsorbs the first gas component and hardly adsorbs the second gas component; and

wherein

in the first and second separation steps, a circulating feed gas being used as the gas to be separated, where the circulating feed gas consists of recovered discharge gases that are discharged when the adsorbents are regenerated, and the feed gas;

a second gas component supplied from the outside is mixed with the circulating feed gas; and

based on at least one of the flow rate and the component concentration of the first gas product, the second gas product is extracted at a constant outflow rate and component concentration by controlling the supply flow rate of the second gas component from the outside.

3. A gas separation method in which principal gas components are separated from a feed gas that includes at least a first gas component and a second gas component using a pressure swing adsorption method comprising:

a first separation step in which the first gas component is separated as a first gas product by using a first adsorbent that hardly adsorbs the first gas component and easily adsorbs the second gas component; and

a second separation step in which the second gas component is separated as a second gas product by using a second adsorbent that easily adsorbs the first gas component and hardly adsorbs the second gas component; and

wherein

in the first and second separation steps, a circulating feed gas is used as the gas to be separated, where the circulating feed gas consists of recovered discharge gases that are discharged when the adsorbents are regenerated, and the feed gas;

a second component gas supplied from the outside is mixed with the circulating feed gas; and

based on at least one of the component concentration in the circulating feed gas and the pressure in the gas delivery path, the second gas product being extracted at a constant outflow rate and component concentration by controlling the supply flow rate of the second gas component from the outside.

9. A gas separation apparatus that separates principal gas components from a feed gas that includes at least a first gas component and a second gas component by using a pressure swing adsorption method, comprising:

a feed gas storage tank into which the feed gas flows,

a compressor for compressing a circulating feed gas from the feed gas storage tank,

a first separation unit having a first adsorption column for separating the first gas component in the circulating feed gas from the compressor as a first gas product, and

a second separation unit having a second adsorption column that separates a second gas component in the circulating feed gas as a second gas product; and

the gas separation apparatus being formed such that;

a first adsorbent that hardly adsorbs the first gas component and easily adsorbs the second gas component is used in a first adsorption column;

a second adsorbent that easily adsorbs the first gas component and hardly adsorbs the second component gas is used in a second adsorption column;

the circulating feed gas, consisting of recovered discharge gases that are discharged when these adsorbents are regenerated and the feed gas, flows into the first or second adsorption columns as gas to be separated; and

based on at least one of the component concentration in the circulating feed gas and the pressure of the gas delivery path, it is possible to adjust the outflow rate of the first gas product.

10. A gas separation apparatus that separates principal gas components from a feed gas that includes at least a first gas component and a second gas component by using a pressure swing adsorption method, comprising:

a feed gas storage tank into which the feed gas flows,

a compressor that compresses a circulating feed gas from the feed gas storage tank,

a first separation unit having a first adsorption column that separates a first gas component in the circulating feed gas from the compressor as a first gas product, and

a second separation unit having a second adsorption column that separates a second gas component in the circulating feed gas as a second gas product; and

the gas separation apparatus being formed such that;

a first adsorbent that hardly adsorbs the first gas component and easily adsorbs the second gas component is used in the first adsorption column;

a second adsorbent that easily adsorbs the first gas component and hardly adsorbs the second gas component is used in the second adsorption column;

the circulating feed gas, consisting of recovered discharge gases that are discharged when these adsorbents are regenerated and the feed gas, flows into the first or second adsorption columns as gas to be separated;

the second gas component can be supplied to the circulating feed gas from the outside; and

based on at least one of the outflow rates and the component concentration of the first gas product, it is possible to adjust the flow rate of the second gas component supplied from the outside.

12. A gas separation apparatus according to any one of the claims 9 to 11, wherein the first adsorbent that fills the first adsorption column is activated carbon, and the second adsorbent that fills the second adsorption column is an adsorbent that can separate krypton or xenon from a mixed gas consisting of krypton or xenon and nitrogen by using the difference in adsorption rates between nitrogen and krypton or xenon.

13. A gas separation apparatus according to claim 12, wherein the pore diameter of the second adsorbent that fills the second adsorption column is approximately 0.4 nm.

14. A gas separation apparatus according to claim 10 or 11, wherein the apparatus is formed such that at least one of the first gas product and the second gas product can be returned to the circulating feed gas based on the flow rate of at least one of the first gas product and the second gas product.

15. A gas separation apparatus according to claim 14, wherein the first adsorbent that fills the first adsorption column is activated carbon, and the second adsorbent that fills the second adsorption column is an adsorbent that can separate krypton or xenon from a mixed gas consisting of krypton or xenon and nitrogen by using the difference in adsorption rates between nitrogen and krypton or xenon.

16. A gas separation apparatus according to claim 15, wherein the pore diameter of the second adsorbent that fills the second adsorption column is approximately 0.4 nm.

11. A gas separation apparatus that separates principal gas components from a feed gas that includes at least a first gas component and a second gas component by using a pressure swing adsorption method, comprising:

a feed gas storage tank into which the feed gas flows,

a compressor for compressing a circulating feed gas from the feed gas storage tank,

a first separation unit having a first adsorption column that separates the first gas component in the circulating feed gas from the compressor as a first gas product; and

a second separation unit having a second adsorption column that separates the second gas component in the circulating feed gas as a second gas product;

the gas separation apparatus being formed such that;

a first adsorbent that hardly adsorbs the first gas component and easily adsorbs the second gas component is used in the first adsorption column;

a second adsorbent that easily adsorbs the first gas component and hardly adsorbs the second component gas is used in the second adsorption column;

the circulating feed gas, consisting of the recovered discharge gases that are discharged when the adsorbents are regenerated and the feed gas, flows into the first or second adsorption columns as gas to be separated;

the second gas component can be supplied to the circulating feed gas from the outside; and

based on at least one of the component concentration in the circulating feed gas and the pressure of the gas delivery path, it is possible to adjust the flow rate of the second gas component supplied from the outside.