Method for using a regenerable catalyzed trap
First Claim
1. A method for removing pollutants comprising nitrogen oxides and sorbable components comprising sulfur oxides and phosphorus oxides from a lean gaseous stream containing the same, the method comprising:
- (a) in a trapping period, passing the gaseous stream within a sorbing temperature range through a catalyzed trap member comprising a combination of a regenerable sorbent material and an oxidation catalyst, and sorbing at least some of said sorbable components into the sorbent material to thereby provide a sorbable component-depleted gaseous stream exiting the catalyzed trap member;
(b) in a desorbing period, introducing a combustible component into the gaseous stream upstream of the catalyzed trap member and combusting the combustible component in the presence of the oxidation catalyst, the combustible component being introduced in an amount which is limited in order to maintain the bulk composition of the gaseous stream lean but which is enough to heat at least a portion of the sorbent material to within a desorbing temperature range to thereby thermally desorb the sorbable component from the sorbent material and provide a sorbable component-enriched gaseous stream exiting the catalyzed trap member; and
(c) passing the sorbable component-depleted stream to a catalytic treatment zone for the abatement of said pollutants and by-passing the sorbable component-enriched stream around said catalytic treatment zone.
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Accused Products
Abstract
A method of at least periodically removing from a lean gaseous stream a sorbable component such as SOx includes passing the gaseous stream through a trap member having an oxidation catalyst combined with a sorbent material at a temperature within the sorbing temperature range of the sorbent material. The sorbed component is periodically removed by introducing a combustible component into the gaseous stream and oxidizing it on the trap member to thermally desorb the sorbed component. The amount of combustible component introduced is limited to maintain the gaseous stream composition lean, but is sufficient to increase the surface temperature of at least part of the trap member to above the bulk temperature of the gaseous stream. Sorbing and desorbing periods are alternated and a composition and an apparatus to carry out the process is provided.
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Citations
12 Claims
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1. A method for removing pollutants comprising nitrogen oxides and sorbable components comprising sulfur oxides and phosphorus oxides from a lean gaseous stream containing the same, the method comprising:
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(a) in a trapping period, passing the gaseous stream within a sorbing temperature range through a catalyzed trap member comprising a combination of a regenerable sorbent material and an oxidation catalyst, and sorbing at least some of said sorbable components into the sorbent material to thereby provide a sorbable component-depleted gaseous stream exiting the catalyzed trap member; (b) in a desorbing period, introducing a combustible component into the gaseous stream upstream of the catalyzed trap member and combusting the combustible component in the presence of the oxidation catalyst, the combustible component being introduced in an amount which is limited in order to maintain the bulk composition of the gaseous stream lean but which is enough to heat at least a portion of the sorbent material to within a desorbing temperature range to thereby thermally desorb the sorbable component from the sorbent material and provide a sorbable component-enriched gaseous stream exiting the catalyzed trap member; and (c) passing the sorbable component-depleted stream to a catalytic treatment zone for the abatement of said pollutants and by-passing the sorbable component-enriched stream around said catalytic treatment zone. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification