Patent ID: 6517801
Filing Date: 2003-02-11
Classification: B01D,C01B,Y02P

Abstract:
A method of treating a feed gas stream containing hydrogen sulphide and carbon dioxide, comprising the steps of:i) burning in a furnace part of the hydrogen sulphide content of the feed gas stream so as to form sulphur dioxide and water vapour, supplying oxygen gas to the furnace to support combustion of the said part of the feed gas stream and reacting in the furnace resulting sulphur dioxide with hydrogen sulphide so as to form an effluent gas stream containing sulphur vapour, water vapour, hydrogen sulphide, sulphur dioxide and carbon dioxide; ii) extracting the sulphur vapour from the effluent gas stream by condensation as to form a sulphur-depleted gas stream; iii) reducing to hydrogen sulphide the sulphur dioxide and other reducible sulphur species in the sulphur-depleted gas stream so as to form a reduced gas stream; iv) removing most of the water vapour from the reduced gas stream so as to form a water vapour-depleted gas stream; v) contacting a first part of the water vapour-depleted gas stream with at least one liquid phase absorbent for hydrogen sulphide in at least one absorber vessel so as selectively to absorb hydrogen sulphide from the water vapour-depleted gas stream and to form a hydrogen sulphide-depleted gas stream; (vi) discharging the hydrogen sulphide-depleted gas stream as a purge stream; (vii) desorbing hydrogen sulphide from the said absorbent so as to form at least one hydrogen sulphide rich gas stream; (viii) returning to the furnace as a first recycle stream or streams at least part of the said hydrogen sulphide rich gas stream; and (ix) returning to the furnace as a second recycle stream a second part of the water vapour-depleted gas stream.