초록 ▼

The concentration of adsorbate in the feed gas to an on-stream bed of a cyclical swing adsorption process is monitored and the data processed to predict the time required to complete the on-stream mode of that bed and the purge flow rate and/or other regeneration mode operating condition of the conc

The concentration of adsorbate in the feed gas to an on-stream bed of a cyclical swing adsorption process is monitored and the data processed to predict the time required to complete the on-stream mode of that bed and the purge flow rate and/or other regeneration mode operating condition of the concurrently off-stream bed is modified in response to changes in said predicted time whereby the regeneration mode of the off-steam bed is completed at the same time as the on-stream mode of the concurrent on-stream bed.

대표청구항 ▼

The invention claimed is: 1. A cyclical swing adsorption process in which one adsorber bed is in an on-stream mode, during which adsorbate is adsorbed from a feed gas mixture passing through the bed, while another adsorber bed is in a regeneration mode, during which the adsorbed adsorbate is desorb

The invention claimed is: 1. A cyclical swing adsorption process in which one adsorber bed is in an on-stream mode, during which adsorbate is adsorbed from a feed gas mixture passing through the bed, while another adsorber bed is in a regeneration mode, during which the adsorbed adsorbate is desorbed from the bed, and said beds alternate between said modes, wherein the time required to complete the on-stream mode is determined by the total amount of the adsorbate in the feed gas mixture fed to the bed during said mode, the concentration of the adsorbate in the feed gas mixture is monitored during said on-stream mode and the time required to complete the on-stream mode predicted from said monitored concentration, and at least one regeneration mode operating condition is modified in response to changes in said predicted time whereby the regeneration mode is completed at the same time as the concurrent on-stream mode. 2. The process according to claim 1, wherein there is a minimum time for completion of the on-stream mode based on a datum concentration of the adsorbate in the feed gas mixture and the predicted time for completion changes only when the monitored concentration exceeds said datum concentration to the extent that the predicted time exceeds said minimum time. 3. The process according to claim 1, wherein the adsorbate is carbon dioxide. 4. The process according to claim 2, wherein the adsorbate is carbon dioxide and said datum concentration is about 400 ppm. 5. The process according to claim 3, wherein the feed gas mixture is air, the said adsorbate is carbon dioxide and water is additionally adsorbed during the on-stream mode. 6. The process according to claim 1, wherein the concentration of the adsorbate is monitored by measurement in the feed gas mixture upstream of the on-stream adsorber bed. 7. The process according to claim 1, wherein the concentration of the adsorbate is monitored by measurement in the on-stream adsorber bed. 8. The process according to claim 1, wherein the at least one regeneration mode operating condition comprises the flow rate of purge gas through the adsorber bed in the regeneration mode. 9. The process according to claim 1, wherein the at least one regeneration mode operating condition comprises the heat of purge gas fed to the adsorber bed in the regeneration mode. 10. The process according to claim 1, wherein the process is a cyclical thermal swing adsorption process. 11. The process according to claim 1, wherein there are two or more adsorbates in the feed gas mixture, the time required to complete the on-stream mode is determined by the total amount of two or more of the adsorbates in the feed gas mixture fed to the bed during said mode, the concentrations of said adsorbates in the feed gas mixture determining the said on-stream time are monitored during said on-stream mode and the time required to complete the on-stream mode predicted from said monitored concentrations, and at least one regeneration mode operating condition is modified in response to changes in said predicted time whereby the regeneration mode is completed at the same time as the concurrent on-stream mode. 12. An air separation process in which air is compressed in a main air compressor to provide compressed air; carbon dioxide is removed from the compressed air by a cyclical swing adsorption process in which one adsorber bed is in an on-stream mode, during which carbon dioxide is adsorbed from the compressed air to provide a carbon dioxide-freed air feed, while another adsorber bed is in a regeneration mode, during which the carbon dioxide is desorbed from the bed, and said beds alternate between said modes; and the carbon dioxide-freed air feed is fed to an air separation unit to provide at least one product stream enriched in a component of the carbon dioxide-freed air feed, wherein the time required to complete the on-stream mode is determined by the total amount of the carbon dioxide in the compressed air, the concentration of the carbon dioxide in the compressed air is monitored during said on-stream mode and the time required to complete the on-stream mode predicted from said monitored concentration, and at least one regeneration mode operating condition is modified in response to changes in said predicted time whereby the regeneration mode is completed at the same time as the concurrent on-stream mode. 13. The air separation process according to claim 12, wherein the concentration of the adsorbate is monitored by measurement in the feed gas mixture upstream of the on-stream adsorber bed. 14. A cyclical swing adsorption apparatus for conducting a process as claimed in claim 1, said apparatus comprising: at least two adsorber beds; a control circuit for maintaining one bed in an on-stream mode for a time determined by total amount of adsorbate in the feed gas mixture fed to the bed during said mode, during which on-stream mode adsorbate can be adsorbed from a feed gas mixture passing through the bed, and another bed in a regeneration mode, during which the adsorbed adsorbate can be desorbed from the bed, and alternating said beds between said modes; and a total adsorber sensor for measuring the total amount of the adsorbate in the feed gas mixture fed to the bed during the on-stream mode, thereby determining the duration of the on-stream mode; a concentration monitor for monitoring the concentration of the adsorbate in the feed gas mixture during said on-stream mode; and a processor for predicting, from said monitored concentration, the time required to complete the on-stream mode, said control circuit modifying at least one regeneration mode operating condition in response to changes in said predicted time whereby the regeneration mode is completed at the same time as the concurrent on-stream mode. 15. A cyclical swing adsorption apparatus for conducting a process as claimed in claim 14, wherein said total adsorber sensor is common with said concentration monitor. 16. The cyclical swing adsorption apparatus according to claim 14, wherein the concentration monitor measures the concentration of the adsorbent in the feed gas mixture upstream of the on-stream adsorber bed. 17. The cyclical swing adsorption apparatus according to claim 14, wherein the concentration monitor measures the concentration of the adsorbent in the on-stream adsorber bed. 18. The cyclical swing adsorption apparatus according to claim 14, wherein the control circuit controls the flow rate of purge gas through the adsorber bed in the regeneration mode. 19. The cyclical swing adsorption apparatus according to claim 14, wherein control circuit controls the heat of purge gas fed to the adsorber bed in the regeneration mode. 20. The cyclical swing adsorption apparatus according to claim 14, wherein the apparatus is a cyclical thermal swing adsorption. 21. An air separation system for conducting a process as claimed in claim 12 comprising: a main air compressor to provide compressed air; a cyclical swing adsorption apparatus to provide a carbon dioxide-freed air feed, and an air separation unit for separating said carbon dioxide-freed air feed to provide at least one product stream enriched in a component thereof, said cyclical swing adsorption apparatus comprising: at least two adsorber beds; a control circuit for maintaining one bed in an on-stream mode for a time determined by total amount of adsorbate in the feed gas mixture fed to the bed during said mode, during which on-stream mode adsorbate can be adsorbed from a feed gas mixture passing through the bed, and another bed in a regeneration mode, during which the adsorbed adsorbate can be desorbed from the bed, and alternating said beds between said modes; and a total adsorber sensor for measuring the total amount of the adsorbate in the feed gas mixture fed to the bed during the on-stream mode, thereby determining the duration of the on-stream mode; a concentration monitor for monitoring the concentration of the adsorbate in the feed gas mixture during said on-stream mode; and a processor for predicting, from said monitored concentration, the time required to complete the on-stream mode, said control circuit modifying at least one regeneration mode operating condition in response to changes in said predicted time whereby the regeneration mode is completed at the same time as the concurrent on-stream mode.