Cryogenic system for removing acid gases from a hydrocarbon gas stream, and method of removing acid gases

摘要

A system for removing acid gases from a raw gas stream the system includes a cryogenic distillation tower. The tower receives and separates the raw gas stream into an overhead methane stream and a bottom liquefied acid gas stream. Refrigeration equipment downstream of the cryogenic distillation tower cools the overhead methane stream and returns a portion of the overhead methane stream to the cryogenic distillation tower as liquid reflux. The system also may include a first molecular sieve bed upstream of the distillation tower and a second molecular sieve bed downstream of the distillation tower. The first molecular sieve bed adsorbs water while the second molecular sieve bed adsorbs additional acid gases from the cooled overhead methane stream.

主权项

1. A system for removing acid gases from a raw gas stream, comprising:
a distillation tower for receiving and then separating the raw gas stream into an overhead methane stream and a bottom liquefied acid gas stream; a first solid adsorbent bed upstream of the distillation tower for at least partially removing a first contaminant from the raw gas stream; and a second solid adsorbent bed downstream of the distillation tower for adsorbing a least some of a second contaminant from the cooled overhead methane stream,
wherein the second solid adsorbent bed downstream of the distillation tower is a regenerated solid adsorbent bed configured for service as the first solid absorbent bed upstream of the distillation tower when saturated with the second contaminant, wherein the distillation tower is a cryogenic distillation tower, the system further comprising: refrigeration equipment downstream of the cryogenic distillation tower for cooling the overhead methane stream and returning a portion of the overhead methane stream to the cryogenic distillation tower as liquid reflux; wherein the refrigeration equipment generates liquid reflux in a sufficient quantity to remove acid gases from the raw gas stream within the cryogenic distillation tower down to a first selected composition, and delivers the overhead methane stream to the second solid adsorbent bed downstream of the cryogenic distillation tower to remove the remaining acid gases down to a second selected composition.