US 12,076,690 B2Granted

Process and plant for purifying crude synthesis gas

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

InventorsAlfred Gubrinski, Sharon Corbet, Dorit Rappold, Pankaj Puri

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Abstract

The invention relates to a process for removal of unwanted, in particular acidic gas constituents, for example carbon dioxide and hydrogen sulfide, from a crude synthesis gas by gas scrubbing with a scrubbing medium. According to the invention the flash gases obtained during the decompression of the laden scrubbing medium are supplied to a recompressor in order to recycle these to the crude synthesis gas and thus utilize them materially after the recompression. Alternatively or in addition the flash gases may also be supplied to a decompression turbine to recover refrigeration and mechanical work. If the recompressor and/or the decompression turbine are/is designed to have multiple stages, the flash gases obtained at different pressure levels are preferably supplied to a corresponding pressure level of the recompressor and/or of the decompression turbine.

Claims6

Dependent claims

A process for purifying a crude synthesis gas by gas scrubbing with a scrubbing medium comprising:

(a) providing and supplying the crude synthesis gas to a prescrubber for removal of trace components,
(b) supplying a gaseous tops product from the prescrubber to an H2S scrubber for removal of H2S,
(c) supplying a gaseous tops product from the H2S scrubber to a CO2 scrubber for removal of CO2,
(d) discharging a purified synthesis gas stream as a gaseous tops product from the CO2 scrubber,
(e) supplying a liquid bottoms product from the prescrubber to an intermediate-pressure prescrubbing flash vessel, supplying a gaseous tops product from the intermediate-pressure prescrubbing flash vessel to a recompressor, supplying a liquid bottoms product from the intermediate-pressure prescrubbing flash vessel to a low-pressure prescrubbing flash vessel, supplying a gaseous tops product from the low-pressure prescrubbing flash vessel to the recompressor, supplying a liquid bottoms product from the low-pressure prescrubbing flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium,
(f) supplying a liquid bottoms product from the H2S scrubber to an intermediate-pressure H2S flash vessel, supplying a gaseous tops product from the intermediate-pressure H2S flash vessel to the recompressor, supplying a liquid bottoms product from the intermediate-pressure H2S flash vessel to a low-pressure H2S flash vessel, supplying a gaseous tops product from the low-pressure H2S flash vessel to the recompressor, supplying a liquid bottoms product from the low-pressure H2S flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium,
(g) supplying a liquid bottoms product from the CO2 scrubber to an intermediate-pressure CO2 flash vessel, supplying a gaseous tops product from the intermediate-pressure CO2 flash vessel to the recompressor, supplying a liquid bottoms product from the intermediate-pressure CO2 flash vessel to a low-pressure CO2 flash vessel, supplying a gaseous tops product from the low-pressure CO2 flash vessel to the low-pressure H2S flash vessel and/or to the recompressor, supplying a liquid bottoms product from the low-pressure CO2 flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium,
(h) recycling the gas stream compressed by the recompressor to the prescrubber for the crude synthesis gas.

5 more elements

A process for purifying a crude synthesis gas by gas scrubbing with a scrubbing medium comprising:

(a) providing and supplying the crude synthesis gas to a prescrubber,
(b) supplying a gaseous tops product from the prescrubber to an H2S scrubber,
(c) supplying a gaseous tops product from the H2S scrubber to a CO2 scrubber,
(d) introducing at least a portion of a gaseous tops product from the CO2 scrubber into a multi-stage expander to recover mechanical work and refrigeration and to discharge an expanded, purified synthesis gas stream from the multi-stage expander,
(e) supplying a liquid bottoms product from the prescrubber to an intermediate-pressure prescrubbing flash vessel, supplying a gaseous tops product from the intermediate-pressure prescrubbing flash vessel to a recompressor, supplying a liquid bottoms product from the intermediate-pressure prescrubbing flash vessel to a low-pressure prescrubbing flash vessel, supplying a gaseous tops product from the low-pressure prescrubbing flash vessel to the recompressor, supplying a liquid bottoms product from the low-pressure prescrubbing flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium,
(f) supplying a liquid bottoms product from the H2S scrubber to an intermediate-pressure H2S flash vessel, supplying a gaseous tops product from the intermediate-pressure H2S flash vessel to the first stage or a subsequent stage of the multi-stage expander or into the conduit downstream of the expander, supplying a liquid bottoms product from the intermediate-pressure H2S flash vessel to a low-pressure H2S flash vessel, supplying a gaseous tops product from the low-pressure H2S flash vessel to the recompressor, supplying a liquid bottoms product from the low-pressure H2S flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium,
(g) supplying a liquid bottoms product from the CO2 scrubber to an intermediate-pressure CO2 flash vessel, supplying a gaseous tops product from the intermediate-pressure CO2 flash vessel to the first stage or a subsequent stage of the multi-stage expander or into the conduit downstream of the expander, supplying a liquid bottoms product from the intermediate-pressure CO2 flash vessel to a low-pressure CO2 flash vessel, supplying a gaseous tops product from the low-pressure CO2 flash vessel to the low-pressure H2S flash vessel and/or to the recompressor, supplying a liquid bottoms product from the low-pressure CO2 flash vessel to at least one apparatus for flash regeneration and/or hot regeneration of the scrubbing medium,
(h) recycling the gas stream compressed by the recompressor to the prescrubber for the crude synthesis gas.

5 more elements

Dependencies are inferred from the claim text.