US4786485A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lignosulfonate-modified calcium hydroxide for SO2 control during furnace injection
Assignee: UNITED STATES ENVIRONMENTAL PROTECTION AGENCY RESEARCH TRIANGLE PARK NORTH CAROLINA
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Filing: 1986-11-12
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Granted: 1988-11-22
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Expires: 2006-11-12
Abstract
Abstract A sorbent is provided for removing sulphur-containing gases from fossil fuel-fired combustors which is a lignosulfonate-modified material comprising calcium hydroxide and/or calcium magnesium hydroxide and an alkali metal lignosulfonate. The sorbent may be introduced downstream of the flame zone of the combustor.
Inventors
- 👤 David A. Kirchgessner
- 👤 Jeffrey M. Lorrain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:05
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/508; B01J; B01J20/00; B01J20/02; B01J20/04; B01J20/041; B01J20/22; B01J20/24; B01J2220/00; B01J2220/40; B01J2220/46; B01J2220/48; B01J2220/4812; B01J2220/4825; B01J2220/4831
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
80 words
A method for removing sulfur oxide sulfur oxide-containing gases from exhaust gases of a fossil fuel-fired combustor comprising the step of introducing into said exhaust gases solid particles capable of reacting with said sulfur oxide-containing gases, said particles comprising a surface-modified sorbent selected from the group consisting of alkali metal lignosulfonate-modified calcium hydroxide and alkali metal lignosulfonate-modified calcium magnesium hydroxide, wherein said alkali metal lignosulfonate comprises up to 5% by weight of the total dry weight of said surface-modified sorbent.
Claim 2
Independent Claim
80 words
A method for removing sulfur oxide sulfur oxide-containing gases from exhaust gases of a fossil fuel-fired combustor comprising the step of introducing into said exhaust gases solid particles capable of reacting with said sulfur oxide-containing gases, said particles comprising a surface-modified sorbent selected from the group consisting of alkali metal lignosulfonate-modified calcium hydroxide and alkali metal lignosulfonate-modified calcium magnesium hydroxide, wherein said alkali metal lignosulfonate comprises up to 5% by weight of the total dry weight of said surface-modified sorbent.
Claim 3
Dependent Claim
20 words
The method according to claim 1, wherein said sorbent comprises calcium hydroxide and said alkali metal lignosulfonate comprises calcium lignosulfonate.
Claim 4
Dependent Claim
16 words
A method according to claim 2 wherein said particles comprise from 1 to 2% calcium lignosulfonate.
Claim 5
Dependent Claim
25 words
A method according to claim 3 wherein the particle size distribution of said particles is finer than the distribution of a corresponding nonlignosulfonate modified sorbent.
Claim 6
Dependent Claim
27 words
A method according to claim 2 wherein said particles are introduced into said exhaust gases at a temperature in the range of about 65° to 1230° C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |