US4908194A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for baghouse brown plume pollution control
Assignee: CRSS Inc
•
Filing: 1988-03-29
•
Granted: 1990-03-13
•
Expires: 2008-03-29
Abstract
Abstract Baghouse SO x /NO x pollution control process comprising injecting from 1 to 25% urea or ammonia along with dry, finely divided sodium bicarbonate or Nahcolite, a naturally occurring form of sodium bicarbonate. The process removes both SO x and NO x from the flue gases of utility and industrial plants, incinerators and the like by dry injection into a flue gas duct a sufficient distance upstream of a baghouse to collect spent reagent and additive. The sodium reagent reacts with the SO 2 to form sodium sulfate and also removes NO x in the form of NO. The urea or ammonia additive prevents the conversion of NO to NO 2 by the sodium reagent, and reduces the concentration of the NO 2 in the exit flue gases to below the NO 2 brown plume visibility threshold (about 30 ppm NO 2 , not corrected to 0% O 2 , depending on ambient conditions). The additive may be used wet (sprayed into the flue gases in a concentrated water solution) or dry.
Inventors
- 👤 Richard G. Hooper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:46
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/60; Y; Y02; Y02A; Y02A50/00; Y02A50/20
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
178 words
An SO x /NO x air pollution control process employing a baghouse to simultaneously control particulate emissions comprising the steps of: (a) introducing a sodium-based reagent into a stream of flue gas containing SO x and NO x , said flue gas having a temperature above about 200° F.; (b) introducing urea as an additive into said flue gases in an amount ranging from about 1 to about 25% by weight of said sodium-based reagent; (c) maintaining said reagent and said additive in contact with said flue gas for a time sufficient to react said reagent with some of said SO x and NO x thereby reducing the concentration of said SO x and NO x in said flue gas; (d) said additive, as compared to use of said reagent without said additive, increasing the percent SO x removal and the percent NO x removal by said reagent while suppressing conversion of NO to NO 2 by said reagent to below about the visible brown plume threshold; and (e) collecting said reacted reagent and additive in a baghouse.
Claim 2
Dependent Claim
178 words
An SO x /NO x air pollution control process employing a baghouse to simultaneously control particulate emissions comprising the steps of: (a) introducing a sodium-based reagent into a stream of flue gas containing SO x and NO x , said flue gas having a temperature above about 200° F.; (b) introducing urea as an additive into said flue gases in an amount ranging from about 1 to about 25% by weight of said sodium-based reagent; (c) maintaining said reagent and said additive in contact with said flue gas for a time sufficient to react said reagent with some of said SO x and NO x thereby reducing the concentration of said SO x and NO x in said flue gas; (d) said additive, as compared to use of said reagent without said additive, increasing the percent SO x removal and the percent NO x removal by said reagent while suppressing conversion of NO to NO 2 by said reagent to below about the visible brown plume threshold; and (e) collecting said reacted reagent and additive in a baghouse.
Claim 3
Dependent Claim
38 words
An SO x /NO x air pollution control process as in claim 1 wherein said sodium-based reagent is selected from the group consisting essentially of sodium bicarbonate, Nahcolite, soda ash, trona, carbonated trona, sodium sesquicarbonate, and combinations thereof.
Claim 4
Dependent Claim
29 words
An SO x /NO x air pollution control process as in claim 2 wherein said reagent is selected from the group consisting essentially of dry Nahcolite and sodium bicarbonate.
Claim 5
Dependent Claim
18 words
An SO x /NO x air pollution control process as in claim 3 wherein said additive is urea.
Claim 6
Dependent Claim
88 words
An SO x /NO x air pollution control process as in claim 4 wherein: (a) said reagent introduction step includes feeding said reagent in a dry, finely divided condition from a first hopper at a metered rate in relation to a predetermined amount of SO x reduction desired; and (b) said urea introduction step includes feeding said urea in a dry crystalline form from a second hopper at a rate within said 1 to 25% by weight range in relation to a predetermined NO 2 removal percent desired.
Claim 7
Dependent Claim
96 words
An SO x /NO x air pollution control process as in claim 4 wherein: (a) said reagent introduction step includes feeding said reagent in a dry finely divided condition into the flue gas to be treated from a hopper at a metered rate in relation to a predetermined amount of SO x reduction desired; and (b) said urea introduction step includes spraying said urea in a solution form into the flue gas to be treated at a rate within said 1 to 25% by weight range in relation to a predetermined NO 2 removal percent desired.
Claim 8
Dependent Claim
30 words
An SO x /NO x air pollution control process as in claim 3 wherein said urea is used in an amount of from about 5% to 25% of said reagent.
Claim 9
Dependent Claim
88 words
An SO x /NO x air pollution control process as in claim 7 wherein: (a) said reagent introduction step includes feeding said reagent in a dry, finely divided condition from a first hopper at a metered rate in relation to a predetermined amount of SO x reduction desired; and (b) said urea introduction step includes feeding said urea in a dry crystalline form from a second hopper at a rate within said 1 to 25% by weight range in relation to a predetermined NO 2 removal percent desired.
Claim 10
Dependent Claim
30 words
An SO x /NO x air pollution control process as in claim 1 wherein said urea is used in an amount of from about 5% to 25% of said reagent.
Claim 11
Dependent Claim
88 words
An SO x /NO x air pollution control process as in claim 9 wherein: (a) said reagent introduction step includes feeding said reagent in a dry, finely divided condition from a first hopper at a metered rate in relation to a predetermined amount of SO x reduction desired; and (b) said urea introduction step includes feeding said urea in a dry crystalline form from a second hopper at a rate within said 1 to 25% by weight range in relation to a predetermined NO 2 removal percent desired.
Claim 12
Dependent Claim
96 words
An SO x /NO x air pollution control process as in claim 13 wherein: (a) said reagent introduction step includes feeding said reagent in a dry, finely divided condition into the flue gas to be treated from a hopper at a metered rate in relation to a predetermined amount of SO x reduction desired; and (b) said urea introduction step includes spraying said urea in a solution form into the flue gas to be treated at a rate within said 1 to 25% by weight range in relation to a predetermined NO 2 removal percent desired.
Claim 13
Dependent Claim
72 words
An SO x /NO x air pollution control process as in claim 4 wherein: (a) said reagent introduction step includes feeding said reagent in a dry finely divided condition into the flue gas to be treated from a hopper at a metered rate in relation to a predetermined amount of SO x reduction desired; and (b) said additive injection steps include spraying concentrated aqueous solutions of said additive into said flue gases.
References Cited (Backward Citations)
US4767605A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-12 | 1993-09-11 | 1994-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-12 | 1997-09-11 | 1998-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-12 | 2001-09-11 | 2002-03-13 | $7700.00 | Window Closed / Lapsed |