Patent US3850741A successfully refreshed from Google Patents.
US3850741A
Expired / Lapsed
US
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Method of cleaning heat exchangers
Assignee: ENCLEAN SPECIALTY CHEMICALS Inc ("ENCLEAN") A CORP OF DE
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Filing: 1973-05-23
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Granted: 1974-11-26
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Expires: 1993-05-23
Abstract
Abstract A method for removing carbonaceous fouling from shell and tube heat exchangers used in hydrocarbon processes which uses as the solvent a highly aromatic hydrocarbon and utilizes heat from the process itself to accomplish the removal of the carbonaceous fouling material is disclosed. This method is particularly useful to maintain the efficiency of heat exchangers between scheduled shutdown of particular units for extensive preventive maintenance.
Inventors
- 👤 J Callahan
- 👤 G Laningham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:08
CPC Classifications
C; C10; C10G; C10G75/00; F; F28; F28G; F28G9/00; F28D; F28D21/00; F28D2021/0019; F28D2021/0059
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
145 words
A METHOD FOR REMOVING CARBONACEOUS FOULING FROM SHELL AND TUBE HEAT EXCHANGERS USED IN HYDROCARBON PROCESSES WHICH COMPRISE THE STEPS OF: A. DISPLACING A PROCESS STREAM ON ONE SIDE OF THE HEAT EXCHANGER WITH A HYDROCARBON SOLVENT HAVING AT LEAST ABOUT 50 WT. PERCENT AROMATIC CONTENT, A KAURI-BUTANOL VALUE OF AT LEAST ABOUT 90 AND A MINIMUM INTIAL BOILING POINT OF AT LEAST ABOUT 350*F AND AN END POINT TEMPERATURE OF AT LEAST ABOUT 500*F, AND RETAINING SAID SOLVENT IN SAID ONE SIDE OF THE HEAT EXCHANGER; B. HEATING THE SOLVENT BEING RETAINED IN ONE SIDE OF THE EXCHANGER BY PASSING A PROCESS STREAM THROUGH THE OTHER SIDE OF THE HEAT EXCHANGER AS IN NORMAL OPERATION OF THE HEAT EXCHANGER FOR A PERIOD OF AT LEAST ABOUT 8 HOURS TO REMOVE THE CARBONACEOUS FOULING; AND C. DISPLACING THE SOLVENT AND REMOVED FOULING WITH PROCESS STREAM.
Claim 2
Independent Claim
145 words
A METHOD FOR REMOVING CARBONACEOUS FOULING FROM SHELL AND TUBE HEAT EXCHANGERS USED IN HYDROCARBON PROCESSES WHICH COMPRISE THE STEPS OF: A. DISPLACING A PROCESS STREAM ON ONE SIDE OF THE HEAT EXCHANGER WITH A HYDROCARBON SOLVENT HAVING AT LEAST ABOUT 50 WT. PERCENT AROMATIC CONTENT, A KAURI-BUTANOL VALUE OF AT LEAST ABOUT 90 AND A MINIMUM INTIAL BOILING POINT OF AT LEAST ABOUT 350*F AND AN END POINT TEMPERATURE OF AT LEAST ABOUT 500*F, AND RETAINING SAID SOLVENT IN SAID ONE SIDE OF THE HEAT EXCHANGER; B. HEATING THE SOLVENT BEING RETAINED IN ONE SIDE OF THE EXCHANGER BY PASSING A PROCESS STREAM THROUGH THE OTHER SIDE OF THE HEAT EXCHANGER AS IN NORMAL OPERATION OF THE HEAT EXCHANGER FOR A PERIOD OF AT LEAST ABOUT 8 HOURS TO REMOVE THE CARBONACEOUS FOULING; AND C. DISPLACING THE SOLVENT AND REMOVED FOULING WITH PROCESS STREAM.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein the solvent and removed fouling are displaced into the process stream itself.
Claim 4
Dependent Claim
23 words
The method of claim 1 wherein the flow of the process stream on the side not being cleaned remains uninterrupted during step (a).
Claim 5
Dependent Claim
20 words
The method of claim 1 wherein the heat exchanger is taken out of service and cooled prior to step (a).
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein the solvent includes about 10 volume percent of a chlorinated benzene.
Claim 7
Dependent Claim
21 words
The method of claim 5 wherein the solvent and removed fouling displaced by the process stream is removed from the process.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein the solvent is a heavy aromatic naphtha.
Claim 9
Dependent Claim
51 words
The method of claim 7 wherein the solvent has an aromatic content of from about 75 wt. percent to 98 wt. percent and a boiling range of from about 400*F minimum initial boiling point to about 600*F minimum end point and a Kauri-butanol value of from about 100 to about 110.
Claim 10
Dependent Claim
21 words
The method of claim 8 wherein the cleaning was continued for a period of from about 18 to about 24 hours.
Claim 11
Independent Claim
167 words
A method for removing carbonaceous fouling on the side of a shell and tube heat exchanger carrying crude oil in the crude preheat train of a petroleum refinery which comprises the steps of: a. displacing the crude in the heat exchanger with a heavy aromatic naphtha solvent having an aromatic content of from about 75 wt. percent to 98 wt. percent, a Kauri-butanol value of about 105 and a boiling range of from about 405*F to about 690*F without interrupting process flow on the other side of said heat exchanger; b. heating the heavy aromatic naphtha being retained on the crude oil side of the exchanger by passing the hot process stream through the other side of said exchanger as in normal operation of the heat exchanger for a period of from about 18 to about 24 hours to remove the carbonaceous fouling; and c. displacing the solvent and removed fouling by flushing the solvent and removed fouling into the crude stream flow with said crude oil.
Claim 12
Independent Claim
167 words
A method for removing carbonaceous fouling on the side of a shell and tube heat exchanger carrying crude oil in the crude preheat train of a petroleum refinery which comprises the steps of: a. displacing the crude in the heat exchanger with a heavy aromatic naphtha solvent having an aromatic content of from about 75 wt. percent to 98 wt. percent, a Kauri-butanol value of about 105 and a boiling range of from about 405*F to about 690*F without interrupting process flow on the other side of said heat exchanger; b. heating the heavy aromatic naphtha being retained on the crude oil side of the exchanger by passing the hot process stream through the other side of said exchanger as in normal operation of the heat exchanger for a period of from about 18 to about 24 hours to remove the carbonaceous fouling; and c. displacing the solvent and removed fouling by flushing the solvent and removed fouling into the crude stream flow with said crude oil.
Claim 13
Dependent Claim
24 words
The method of claim 10 wherein the exit valve of the crude oil side remains open during heating of the solvent being retained therein.
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) | 1977-11-25 | 1978-05-27 | 1978-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-25 | 1982-05-27 | 1982-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-25 | 1986-05-27 | 1986-11-26 | $7700.00 | Window Closed / Lapsed |