Method And Apparatus For Separating Gases
First Claim
1. A method of removing a gas dissolved in a liquid under pressure, said method comprising:
- reducing the pressure on said liquid at a first expansion ratio, a first portion of said gas being thereby released from said liquid;
separating said first portion of said gas from said liquid;
reducing the pressure on said liquid at a second expansion ratio greater than said first expansion ratio, a second portion of said gas being thereby released from said liquid;
separating said second portion of said gas from said liquid; and
reducing the pressure on said liquid at a third expansion ratio greater than said second expansion ratio, a third portion of said gas being thereby released from said liquid.
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Accused Products
Abstract
A method and apparatus for removing carbon dioxide from a synthesis gas stream containing hydrogen is disclosed. The method includes absorbing the carbon dioxide using a physical solvent under high pressure and then liberating the carbon dioxide in a series of expansion stages where the pressure on the solvent is reduced. The expansion ratio increases with each expansion stage. The apparatus includes expansion stages having throttling devices and expansion tanks operated at increasing expansion ratios. Carbon dioxide is liberated in this manner so as to minimize the energy required compress for transport via a pipe line for sequestration of the gas. Sequestration of the carbon dioxide is preferred to atmospheric venting to curb the release of greenhouse gases.
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Citations
21 Claims
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1. A method of removing a gas dissolved in a liquid under pressure, said method comprising:
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reducing the pressure on said liquid at a first expansion ratio, a first portion of said gas being thereby released from said liquid; separating said first portion of said gas from said liquid; reducing the pressure on said liquid at a second expansion ratio greater than said first expansion ratio, a second portion of said gas being thereby released from said liquid; separating said second portion of said gas from said liquid; and reducing the pressure on said liquid at a third expansion ratio greater than said second expansion ratio, a third portion of said gas being thereby released from said liquid. - View Dependent Claims (2)
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3. A method of removing a gas dissolved in a liquid under pressure, said method comprising:
reducing the pressure on said liquid in a product recovery pressure reduction stage and a plurality of subsequent pressure reduction stages beginning with a first subsequent pressure reduction stage, wherein each subsequent pressure reduction stage after said first subsequent pressure reduction stage occurs at an expansion ratio greater than the pressure reduction stage which preceded it, a portion of said gas being released from said liquid at each pressure reduction stage. - View Dependent Claims (4, 5)
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6. A method of removing carbon dioxide from a gas mixture comprising hydrogen, said method comprising:
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bringing said gas mixture into contact with a liquid physical solvent under pressure, said solvent preferentially absorbing carbon dioxide from said gas mixture; reducing the pressure on said solvent in a product recovery pressure reduction stage; further reducing the pressure on said solvent in a plurality of subsequent pressure reduction stages beginning with a first subsequent pressure reduction stage, wherein each subsequent pressure reduction stage after said first subsequent pressure reduction stage occurs at an expansion ratio greater than the pressure reduction stage which preceded it, a portion of said carbon dioxide absorbed by said solvent being released from said solvent at each pressure reduction stage. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus for removing gases dissolved in a liquid under pressure, said apparatus comprising:
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a first expansion means adapted to receive said solvent, gases dissolved in said solvent being released from said solvent in said first expansion means; a second expansion means adapted to receive said solvent from said first expansion means, said gases being released from said solvent in said second expansion means; a third expansion means adapted to receive said solvent from said second expansion means, said gases being released from said solvent in said third expansion means;
whereinsaid second expansion means is configured to reduce the pressure on said solvent at an expansion ratio greater than the expansion ratio of said first expansion means, and said third expansion means is configured to reduce the pressure on said solvent at an expansion ratio greater than the expansion ratio of said second expansion means. - View Dependent Claims (16)
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17. An apparatus for removing carbon dioxide from a gas mixture using a liquid physical solvent to preferentially absorb said carbon dioxide and yield a product gas having a lower concentration of carbon dioxide than said gas mixture, said apparatus comprising:
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an absorption vessel adapted to bring said liquid physical solvent into contact with said gas mixture under pressure, said absorption vessel having a solvent inlet for admitting said solvent to said absorption vessel, a gas inlet for admitting said gas mixture to said absorption vessel, a gas outlet for releasing said product gas from said absorption vessel, and a solvent outlet for releasing said solvent from said absorption vessel; a product recovery expansion means adapted to receive said solvent from said absorption vessel, carbon dioxide and other gases absorbed from said gas mixture being released from said solvent in said product recovery expansion means; a compressor having an inlet in fluid communication with said product recovery expansion means and an outlet in fluid communication with said gas inlet of said absorption vessel, said compressor moving gases released from said solvent in said product recovery expansion means back to said absorption vessel; a first expansion means adapted to receive said solvent from said product recovery expansion means, carbon dioxide being released from said solvent in said first expansion means; a second expansion means adapted to receive said solvent from said first expansion means, carbon dioxide being released from said solvent in said second expansion means; a third expansion means adapted to receive said solvent from said second expansion means, carbon dioxide being released from said solvent in said third expansion means; a compressor facility in fluid communication with said first, second, and third expansion means for receiving the carbon dioxide released from said solvent, said compressor facility compressing said carbon dioxide for transport away therefrom;
whereinsaid second expansion means is configured to reduce the pressure on said solvent at an expansion ratio greater than the expansion ratio of said first expansion means, and said third expansion means is configured to reduce the pressure on said solvent at an expansion ratio greater than the expansion ratio of said second expansion means. - View Dependent Claims (18, 19, 20, 21)
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Specification