Systems and methods for removing sulfur dioxide from a gas stream

摘要

Methods for removing sulfur dioxide front a gas stream are disclosed. A method may include passing a gas stream comprising SO2 through a gas scrubbing apparatus. A scrubbing liquor comprising hydroxide ions and at least one oxidation catalyst may be flowed into the gas scrubbing apparatus, thereby contacting the gas stream with the scrubbing liquor. In response to the contacting, at least 90 wt. % of the sulfur dioxide may be removed from the gas stream. Concomitant to the contacting, at least some of the sulfur dioxide may react with at least some of the hydroxide ions, thereby forming sulfite ions in the scrubbing liquor. Some of the sulfite ions may be oxidized, via the oxidation catalyst, thereby forming sulfate ions in the scrubbing liquor. A used scrubbing liquor may be discharged from the scrubbing apparatus.

主权项

1. A method comprising:
(a) passing a gas stream (110) comprising SO2 (112) through a gas scrubbing apparatus (100);
wherein, prior to the passing step, the SO2 concentration in the gas stream is from 1 to 400 ppm; (b) first flowing a scrubbing liquor (160) comprising hydroxide ions (162), and at least one oxidation catalyst (164) through a liquid inlet (142) of the gas scrubbing apparatus;
wherein, during the flowing, the scrubbing liquor (160) comprises at least 5 ppm of the oxidation catalyst; (c) contacting, in the scrubbing apparatus, the gas stream (110) with the scrubbing liquor (160); (d) removing, in response to the contacting step, at least 90 wt. % of the SO2 from the gas stream, thereby creating a treated gas stream (120); (e) concomitant to the contacting step:
(i) reacting at least some of the SO2 with at least some of the hydroxide ions thereby forming sulfite ions (132) in the scrubbing liquor;(ii) oxidizing some of the sulfite ions via the oxidation catalyst thereby forming sulfate ions (134) in the scrubbing liquor; (f) second flowing a used scrubbing liquor (130) comprising at least some of the sulfite ions (132) and at least some of the sulfate ions (134) through a liquid outlet (144) of the scrubbing apparatus (100).