US5246594A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for controlling the ph value of an acid scrubbing liquid
Assignee: GEA Group AG
•
Filing: 1992-05-15
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Granted: 1993-09-21
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Expires: 2012-05-15
Abstract
Abstract The acid scrubbing liquid which has a pH value below 3 and is used in a scrubbing zone to remove acid components from a gas. At least part of the scrubbing liquid is circulated. A partial stream of the scrubbing liquid at a constant rate is mixed with an alkaline solution stream which has a constant concentration and is supplied at a constant volume rate, the pH value of the resulting mixture is continually measured, a setpoint in the range from 5 to 9 is selected for the pH value of the mixture, and a neutral or alkaline correcting liquid is added to the scrubbing liquid in response to a decrease of the measured pH value below said setpoint. The scrubbing liquid may mainly consist of water.
Inventors
- 👤 Bertold Stegemann
- 👤 Gunter Kloos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:38
CPC Classifications
G; G05; G05D; G05D21/00; B; B01; B01D; B01D53/00; B01D53/34; B01D53/346; B01D53/46; B01D53/68; G05D21/02
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
149 words
A process for scrubbing a gas, comprising said steps of: (a) passing a gas through a scrubber into contact with a scrubbing solution having a pH at most 3 and collecting said scrubbing solution following contact of said gas therewith; (b) recirculating said collected scrubbing solution into contact with said gas; (c) feeding collected scrubbing solution at a constant rate into admixture with an alkaline solution fed at a constant rate and having a predetermined alkaline concentration thereby forming a mixture having a set point pH in a range of from 5 to 9 and feeding said mixture to said scrubbing solution; (d) continuously measuring a pH of said mixture; and (e) upon a decrease of said pH measured in step (d) from said set point pH adding to said scrubbing solution a liquid capable of raising said pH, thereby restoring pH of said mixture to said set point.
Claim 2
Dependent Claim
149 words
A process for scrubbing a gas, comprising said steps of: (a) passing a gas through a scrubber into contact with a scrubbing solution having a pH at most 3 and collecting said scrubbing solution following contact of said gas therewith; (b) recirculating said collected scrubbing solution into contact with said gas; (c) feeding collected scrubbing solution at a constant rate into admixture with an alkaline solution fed at a constant rate and having a predetermined alkaline concentration thereby forming a mixture having a set point pH in a range of from 5 to 9 and feeding said mixture to said scrubbing solution; (d) continuously measuring a pH of said mixture; and (e) upon a decrease of said pH measured in step (d) from said set point pH adding to said scrubbing solution a liquid capable of raising said pH, thereby restoring pH of said mixture to said set point.
Claim 3
Dependent Claim
16 words
The process defined in claim 1 wherein said set point pH range is 6 to 8.
Claim 4
Dependent Claim
18 words
The process defined in claim 1 wherein said pH in said set point pH range is about 7.
Claim 5
Dependent Claim
13 words
The process defined in claim 1 wherein said liquid is a neutral liquid.
Claim 6
Dependent Claim
13 words
The process defined in claim 1 wherein said liquid is an alkaline liquid.
Claim 7
Dependent Claim
27 words
The process defined in claim 1 wherein said liquid is added to a sump of said scrubber in which the scrubbing solution is collected in step (a).
Claim 8
Dependent Claim
45 words
The process defined in claim 1 wherein a level of the scrubbing solution is maintained constant by the addition of water thereto, a portion of scrubbing solution being discharged in response to said decrease of the pH, thereby restoring pH by said addition of water.
Claim 9
Dependent Claim
23 words
The process defined in claim 1 wherein the collected scrubbing solution at a constant rate is withdrawn from the recirculated collected scrubbing solution.
Claim 10
Dependent Claim
16 words
The process defined in claim 1 wherein said liquid is added to the recirculated scrubbing solution.
Claim 11
Dependent Claim
128 words
A process of controlling the pH value of an acid scrubbing liquid, which is used at a pH value below 3 in a scrubbing zone for removing acid components from a gas and is circulated at least in part, comprising the steps of: (a) mixing a partial stream of the scrubbing liquid at a constant rate with an alkaline solution stream which has a constant concentration and is supplied at a constant volume rate; (b) continuously measuring the pH value of the resulting mixture; (c) maintaining a setpoint in the range from 5 to 9 for the pH value of the mixture; and (d) adding a neutral or alkaline correcting liquid to the scrubbing liquid in response to a decrease of the measured pH value below said setpoint.
Claim 12
Dependent Claim
128 words
A process of controlling the pH value of an acid scrubbing liquid, which is used at a pH value below 3 in a scrubbing zone for removing acid components from a gas and is circulated at least in part, comprising the steps of: (a) mixing a partial stream of the scrubbing liquid at a constant rate with an alkaline solution stream which has a constant concentration and is supplied at a constant volume rate; (b) continuously measuring the pH value of the resulting mixture; (c) maintaining a setpoint in the range from 5 to 9 for the pH value of the mixture; and (d) adding a neutral or alkaline correcting liquid to the scrubbing liquid in response to a decrease of the measured pH value below said setpoint.
Claim 13
Dependent Claim
14 words
The process according to claim 1 wherein the scrubbing liquid consists mainly of water.
Claim 14
Dependent Claim
25 words
The process according to claim 1 wherein the pH value of the scrubbing liquid withdrawn from the scrubbing zone is not in excess of 2.
Claim 15
Dependent Claim
13 words
The process according to claim 1 wherein the correcting liquid consists of water.
Claim 16
Dependent Claim
39 words
The process according to claim 1 wherein a salt content of the scrubbing liquid is measured and in case of an undesirably high salt content, a part of the scrubbing liquid is removed from circulation and replaced by water.
Claim 17
Dependent Claim
24 words
The process according to claim 1 wherein the liquid mixture from the means for measuring the pH value is supplied to the scrubbing liquid.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-09-20 | 1997-03-22 | 1997-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-20 | 2001-03-22 | 2001-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-20 | 2005-03-22 | 2005-09-21 | $7700.00 | Window Closed / Lapsed |