Process for removing s02 from gas with s02 content that is temporarily very high
AssigneeCansolv Technologies Inc.
InventorsXijian LI, FengDan WANG
Life of this patent
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Abstract
The invention is directed to a process and a system for removing sulfur dioxide from a feed gas stream. In the process the feed gas pre-scrubbed. Then SO2 is absorbed from the gas with an absorbing medium. The spent absorbing medium is regenerated. These process steps are interchanged with a caustic treatment in the pre-scrubbing zone in case of a very high SO2 content in the feed gas stream. The system comprises a pre-scrubbing unit, an absorption unit, and a regeneration unit. The system is characterized in that the pre-scrubber unit comprises an inlet for an aqueous solution comprising a strong base. These are a simple, cost-efficient and reliable process and facility for processing gas with a varying SO2 content.
Claims10
A process for removing sulfur dioxide from a feed gas stream, which process comprises:
- (i) contacting the feed gas stream with an aqueous stream in a pre-scrubbing zone;
- (ii) contacting at least a part of the pre-scrubbed gas stream obtained in step (i) with an aqueous lean absorbing medium in an absorption zone to absorb sulfur dioxide and to form a sulfur dioxide lean treated gas stream and a spent absorbing medium;
- (iii) stripping, preferably steam stripping, absorbed sulfur dioxide from at least a part of the spent absorbing medium obtained in step (ii) in a regeneration zone to form a regenerated aqueous absorbing medium and gas stream comprising sulfur dioxide;
- (iv) optionally recycling at least a portion of the regenerated aqueous absorbing medium obtained in step (iii) to step (ii);
- (v) optionally feeding the gas stream comprising sulfur dioxide to a Sulfur Removal Unit, preferably to a Claus Sulfur Removal Unit;
- whereby the series of steps (i) to (v) is interchanged with:
- (A) contacting the feed gas stream with an aqueous solution comprising a strong base in the pre-scrubbing zone to form a sulfur dioxide lean treated gas stream and an aqueous solution comprising sulfite and/or bisulfite ions.
A system for removing sulfur dioxide from a feed gas stream, which system comprises:
- a pre-scrubbing unit, preferably a pre-scrubbing tower, comprising a gas inlet, a gas outlet, a water inlet, and a water outlet, and a cooling unit;
- an absorption unit comprising a gas inlet, a gas outlet, an inlet for absorbing medium, and an outlet for absorbing medium, which absorption unit is in fluid communication with the pre-scrubbing unit to receive at least part of a pre-scrubbed gas stream;
- a regeneration unit comprising a gas inlet, a gas outlet, an inlet for absorbing medium, and an outlet for absorbing medium, which regeneration unit is in fluid communication with the absorption unit to receive at least part of a spent absorbing medium;
- the system characterized in that the pre-scrubber unit comprises an inlet for an aqueous solution comprising a strong base.
Dependencies are inferred from the claim text.