EP0076683A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus and method for controlling the pH of a continuous process stream
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1982-10-04
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Granted: —
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Expires: 2002-10-04
Abstract
Abstract The invention provides a pH control system and method for maintaining the proper pH in a continuous process stream (20, 27). A continuous sample stream (21) has its pH and composition time-averaged in a backmixing vessel (22) to reduce the dynamic gain of the pH control system, and the pH of the time-averaged sample is determined by a pH analyzer (23). A pH controller (24) is responsive to the pH as determined by the analyzer (23) to control the rate of addition of reagent or buffer to the process stream (by regulating the setting of valve 25) on a continuous basis.
Inventors
- 👤 Loren H. Haag
- 👤 Richard Weber
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 18:53
CPC Classifications
G; G05; G05D; G05D21/00; G05D21/02; B; B01; B01D; B01D53/00; B01D53/14; B01D53/1412; B01D53/1425; B01D53/1456; B01D53/1468; Y; Y10; Y10T; Y10T436/00; Y10T436/12
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
152 words
A system for controlling the pH of a continuous process stream characterized in that it comprises : (a) a conduit (20, 27) for substantially continuously conveying a process stream; (b) a pH analyzing means (23); (c) means (22) for time-averaging the pH and composition of liquid samples, said means (22) being connected (21) for receiving a substantially continuous sample of said process stream from said conduit (20, 27) and connected for the passage of time-averaged samples to the pH analyzing means (23); and (d) pH control means (24) connected to said conduit (20) upstream of the connection (21) to the time-averaging means (22), said pH control means (24) being operatively connected to said pH analyzing means (23) and being operative in response to said analysis of said pH analyzing means (23) for delivering reagent (via 25) to said process stream (20) to achieve a desired pH for said process stream (20, 27).
Claim 2
Independent Claim
152 words
A system for controlling the pH of a continuous process stream characterized in that it comprises : (a) a conduit (20, 27) for substantially continuously conveying a process stream; (b) a pH analyzing means (23); (c) means (22) for time-averaging the pH and composition of liquid samples, said means (22) being connected (21) for receiving a substantially continuous sample of said process stream from said conduit (20, 27) and connected for the passage of time-averaged samples to the pH analyzing means (23); and (d) pH control means (24) connected to said conduit (20) upstream of the connection (21) to the time-averaging means (22), said pH control means (24) being operatively connected to said pH analyzing means (23) and being operative in response to said analysis of said pH analyzing means (23) for delivering reagent (via 25) to said process stream (20) to achieve a desired pH for said process stream (20, 27).
Claim 3
Dependent Claim
60 words
The system of claim 1 further characterized by comprising a static mixing means (26) disposed in said conduit (20) between the location at which reagent is added to the process stream (20) and the location at which a substantially continuous sample is passed (21) to the time-averaging means (22) for thoroughly mixing any added reagent with the process stream (20).
Claim 4
Dependent Claim
47 words
The system of claim 1 or claim 2 further characterized by comprising a rapid oxidation zone or vessel (31) connected between said pH analyzing means (23) and said time-averaging means (22) for rapidly oxidizing the time-averaged sample prior to pH analysis in the pH analyzing means (23).
Claim 5
Independent Claim
32 words
The system of any one of claims 1 to 3 further characterized by comprising an oxidation basin (30) connected to said conduit (27) downstream of the connection to said time-averaging means (22).
Claim 6
Independent Claim
22 words
The system of any one of claims 1 to 4 further characterized in that said time-averaging means (22) comprises a backmixing vessel.
Claim 7
Dependent Claim
26 words
The system of claim 5 further characterized by means for passing part of the sample leaving the backmixing vessel into the sample entering the backmixing vessel.
Claim 8
Independent Claim
28 words
The system of any one of claims 1 to 6 characterized by being in combination with a wet-gas scrubber for neutralizing the acidity of the wet-gas scrubber effluent.
Claim 9
Independent Claim
100 words
A method of continuously controlling the pH of a process stream, characterized in that it comprises the steps of: (a) obtaining (21) a substantially continuous sample of the process stream; (b) time-averaging (22) the sample (e.g. by returning to the entrance of a vessel a portion of the sample leaving the vessel); (c) substantially continuously determining or analyzing (23) the pH of said time-averaged sample; and (d) substantially continuously adding (25) a reagent to an upstream portion (20) of the process stream to control the pH of the sample stream (21) in response to the pH-analysis of the time-averaged sample.
Claim 10
Independent Claim
100 words
A method of continuously controlling the pH of a process stream, characterized in that it comprises the steps of: (a) obtaining (21) a substantially continuous sample of the process stream; (b) time-averaging (22) the sample (e.g. by returning to the entrance of a vessel a portion of the sample leaving the vessel); (c) substantially continuously determining or analyzing (23) the pH of said time-averaged sample; and (d) substantially continuously adding (25) a reagent to an upstream portion (20) of the process stream to control the pH of the sample stream (21) in response to the pH-analysis of the time-averaged sample.
Claim 11
Dependent Claim
27 words
The method of claim 8 further characterized by comprising the step of : (e) statically mixing (26) the added reagent (from 25) into said process stream (20).
Claim 12
Dependent Claim
28 words
The method of claim 8 or claim 9 further characterized by comprising the step of (f) rapidly oxidizing (31) the time-averaged sample prior to the analyzing step (c).
References Cited (Backward Citations)
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