Gas separation process
First Claim
1. A process for separating CO2 from a first gas stream comprising CO2, the process comprising the steps of:
- (a) calcining an alkaline earth metal carbonate to generate an alkaline earth metal oxide and produce a first product gas stream comprising CO2;
(b) contacting the alkaline earth metal oxide with the first gas stream to carbonate the alkaline earth metal oxide and regenerate the alkaline earth metal carbonate;
(c) calcining the alkaline earth metal carbonate regenerated in step (b) to regenerate the alkaline earth metal oxide and produce a second product gas stream comprising CO2;
(d) optionally repeating steps (b) and (c) using the alkaline earth metal oxide regenerated in step (c);
(e) contacting the alkaline earth metal oxide regenerated in step (c) with water to form an alkaline earth metal hydroxide;
(f) heating the alkaline earth metal hydroxide in a second gas stream comprising CO2 to a temperature that is higher than the normal decomposition temperature for the alkaline earth metal hydroxide;
(g) dehydrating the alkaline earth metal hydroxide to regenerate the alkaline earth metal oxide;
(h) optionally repeating steps (e) to (g) using the alkaline earth metal oxide regenerated in step (g);
(i) contacting the alkaline earth metal oxide regenerated in step (g) with a third gas stream comprising CO2 to carbonate the alkaline earth metal oxide and regenerate the alkaline earth metal carbonate;
(j) optionally repeating steps (c) to (i) using the alkaline earth metal carbonate regenerated in step (i); and
(k) repeating steps (a) to (c), (e) to (g), and (i), and one or more of steps (d), (h), and (j) when performed, using the alkaline earth metal carbonate regenerated in step (i).
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Accused Products
Abstract
A process for the separation of carbon dioxide from gas mixtures is disclosed in which a metal oxide sorbent, which is used to capture and release carbon dioxide, is recycled. The process incorporates the regeneration of the carbon dioxide capture capacity of the metal oxide to maintain a high capture capacity over many cycles. The regeneration involves hydrating the metal oxide and then heating the resulting metal hydroxide under a gas atmosphere that is effective to suppress the dehydration of the hydroxide so that dehydration occurs at an elevated temperature. The regeneration may also be used independently from the carbon dioxide separation process to produce, from a metal hydroxide, a metal oxide having an enhanced resistance to attrition and fragmentation.
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Citations
21 Claims
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1. A process for separating CO2 from a first gas stream comprising CO2, the process comprising the steps of:
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(a) calcining an alkaline earth metal carbonate to generate an alkaline earth metal oxide and produce a first product gas stream comprising CO2; (b) contacting the alkaline earth metal oxide with the first gas stream to carbonate the alkaline earth metal oxide and regenerate the alkaline earth metal carbonate; (c) calcining the alkaline earth metal carbonate regenerated in step (b) to regenerate the alkaline earth metal oxide and produce a second product gas stream comprising CO2; (d) optionally repeating steps (b) and (c) using the alkaline earth metal oxide regenerated in step (c); (e) contacting the alkaline earth metal oxide regenerated in step (c) with water to form an alkaline earth metal hydroxide; (f) heating the alkaline earth metal hydroxide in a second gas stream comprising CO2 to a temperature that is higher than the normal decomposition temperature for the alkaline earth metal hydroxide; (g) dehydrating the alkaline earth metal hydroxide to regenerate the alkaline earth metal oxide; (h) optionally repeating steps (e) to (g) using the alkaline earth metal oxide regenerated in step (g); (i) contacting the alkaline earth metal oxide regenerated in step (g) with a third gas stream comprising CO2 to carbonate the alkaline earth metal oxide and regenerate the alkaline earth metal carbonate; (j) optionally repeating steps (c) to (i) using the alkaline earth metal carbonate regenerated in step (i); and (k) repeating steps (a) to (c), (e) to (g), and (i), and one or more of steps (d), (h), and (j) when performed, using the alkaline earth metal carbonate regenerated in step (i). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A process for separating CO2 from a first gas stream comprising CO2, the process comprising the steps of:
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(a) contacting an alkaline earth metal oxide with the first gas stream to carbonate the alkaline earth metal oxide and form an alkaline earth metal carbonate; (b) calcining the alkaline earth metal carbonate to regenerate the alkaline earth metal oxide and produce a product gas stream comprising CO2; (c) repeating steps (a) and (b) using the alkaline earth metal oxide regenerated in step (b); (d) contacting the alkaline earth metal oxide regenerated in step (b) with water to form an alkaline earth metal hydroxide; (e) heating the alkaline earth metal hydroxide in a second gas stream comprising CO2 to a temperature that is higher than the normal decomposition temperature for the alkaline earth metal hydroxide; (f) dehydrating the alkaline earth metal hydroxide in a third gas stream to regenerate the alkaline earth metal oxide; and (g) repeating steps (a) to (f) using the alkaline earth metal oxide regenerated in step (f). - View Dependent Claims (21)
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Specification