US 12,502,638 B2Granted

Process and plant for removing carbon dioxide from synthesis gas

AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude

InventorSophia Schmidt

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Abstract

The present invention relates to a process for removing carbon dioxide from a synthesis gas having at least hydrogen and carbon dioxide in which the synthesis gas is at least partially freed of carbon dioxide in an absorption apparatus by physical absorption at elevated absorption pressure. The carbon dioxide is subsequently desorbed by pressure reduction relative to the absorption pressure in a plurality of serially arranged flash stages and an at least partially regenerated absorption medium is withdrawn from the last of the plurality of serially arranged flash stages, recompressed to absorption pressure and recycled into the absorption apparatus for use as absorption medium. It is also provided according to the invention that a partially regenerated absorption medium from a flash stage upstream of the last of the plurality of serially arranged flash stages is recompressed to absorption pressure and recycled into the absorption apparatus for use as absorption medium.

Claims17

Dependent claims

A process for removing carbon dioxide from synthesis gas, wherein the synthesis gas comprises at least hydrogen and carbon dioxide, comprising the steps of

(a) providing a physical absorption medium;
(b) supplying the synthesis gas to an absorption apparatus and removing carbon dioxide from the synthesis gas by physical absorption of the carbon dioxide in the absorption medium at absorption pressure in the absorption apparatus, wherein the absorption medium and the synthesis gas are run in countercurrent in the absorption apparatus and wherein an absorption medium laden at least with carbon dioxide and a synthesis gas at least partially freed of carbon dioxide are withdrawn from the absorption apparatus;
(c) removing carbon dioxide from the laden absorption medium withdrawn from the absorption apparatus by desorption of the carbon dioxide in a plurality of serially arranged flash stages by pressure reduction relative to the absorption pressure, wherein the pressure prevailing in a flash stage is reduced from flash stage to flash stage in the flow direction of the absorption medium;
(d) withdrawing an at least partially regenerated absorption medium from the last of the plurality of serially arranged flash stages, recompressing the at least partially regenerated absorption medium to absorption pressure and recycling the at least partially regenerated compressed absorption medium for use as absorption medium in the absorption apparatus according to step (b);
(e) withdrawing a partially regenerated absorption medium from a flash stage upstream of the last of the plurality of serially arranged flash stages, recompressing the partially regenerated absorption medium to absorption pressure and recycling the partially regenerated compressed absorption medium for use as absorption medium in the absorption apparatus according to step (b).

2 more elements

A plant for removing carbon dioxide from synthesis gas, wherein the synthesis gas comprises at least hydrogen and carbon dioxide, comprising the following plant components in operative connection with one another:

(a) a means for providing a physical absorption medium;
(b) an absorption apparatus and a means for supplying the synthesis gas to the absorption apparatus, wherein the absorption apparatus is configured such that the carbon dioxide is removable from the synthesis gas by physical absorption in the absorption medium at absorption pressure and the absorption apparatus is configured such that the absorption medium and the synthesis gas may be run in countercurrent in the absorption apparatus and wherein the absorption apparatus is further configured such that an absorption medium laden at least with carbon dioxide and a synthesis gas at least partially freed of carbon dioxide are withdrawable from the absorption apparatus;
(c) a means for removing carbon dioxide from the laden absorption medium withdrawable from the absorption apparatus by desorption, wherein the means comprise at least a plurality of serially arranged flash stages, wherein said flash stages are configured such that a pressure reduction relative to the absorption pressure may be carried out therein and the flash stages are further configured such that the pressure prevailing in a flash stage can decrease from flash stage to flash stage in the flow direction of the medium;
(d) a means for withdrawing an at least partially regenerated absorption medium from the last of the plurality of serially arranged flash stages, a means for recompressing the at least partially regenerated absorption medium to absorption pressure and means for recycling the at least partially regenerated compressed absorption medium for use as absorption medium in the absorption apparatus according to (b);
(e) a means for withdrawing a partially regenerated absorption medium from a flash stage upstream of the last of the plurality of serially arranged flash stages, means for recompressing the partially regenerated absorption medium to absorption pressure and a means for recycling the partially regenerated compressed absorption medium for use as absorption medium in the absorption apparatus according to (b).

2 more elements

Dependencies are inferred from the claim text.