GB1577760A - Creation of Inventions and Patents with Artificial Intelligence

GB1577760A – Clean heat exchangers
– Google Patents

GB1577760A – Clean heat exchangers
– Google Patents
Clean heat exchangers

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Publication number
GB1577760A

GB1577760A
GB14148/77A
GB1414877A
GB1577760A
GB 1577760 A
GB1577760 A
GB 1577760A
GB 14148/77 A
GB14148/77 A
GB 14148/77A
GB 1414877 A
GB1414877 A
GB 1414877A
GB 1577760 A
GB1577760 A
GB 1577760A
Authority
GB
United Kingdom
Prior art keywords
methanol
heat exchange
water
weight percent
exchange surfaces
Prior art date
1977-04-04
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)

Expired

Application number
GB14148/77A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)

British Gas Corp

Original Assignee
British Gas Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1977-04-04
Filing date
1977-04-04
Publication date
1980-10-29

1977-04-04
Application filed by British Gas Corp
filed
Critical
British Gas Corp

1977-04-04
Priority to GB14148/77A
priority
Critical
patent/GB1577760A/en

1977-11-02
Priority to US05/847,981
priority
patent/US4167100A/en

1978-01-19
Priority to CA295,318A
priority
patent/CA1106266A/en

1978-01-25
Priority to AU32716/78A
priority
patent/AU509657B2/en

1978-01-27
Priority to ZA00780516A
priority
patent/ZA78516B/en

1978-02-20
Priority to DE19782807223
priority
patent/DE2807223A1/en

1978-02-22
Priority to JP1865378A
priority
patent/JPS53122967A/en

1980-10-29
Publication of GB1577760A
publication
Critical
patent/GB1577760A/en

Status
Expired
legal-status
Critical
Current

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Classifications

F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING

F28—HEAT EXCHANGE IN GENERAL

F28G—CLEANING OF INTERNAL OR EXTERNAL SURFACES OF HEAT-EXCHANGE OR HEAT-TRANSFER CONDUITS, e.g. WATER TUBES OR BOILERS

F28G9/00—Cleaning by flushing or washing, e.g. with chemical solvents

Description

PATENT SPECIFICATION
( 21) Application No 14148/77 ( 22) Filed 4 April 1977 ( 23) Complete Specification filed 21 March 1978 ( 44) Complete Specification published 29 Oct 1980 ( 51) INT CL 3 F 25 D 21/10 ( 52) Index at acceptance F 4 H G 15 ( 72) Inventors JOHN HAMILTON ALSTON RAMAGE and RICHARD GARY WINTER ( 54) IMPROVEMENTS IN OR RELATING TO CLEAN HEAT EXCHANGERS ( 71) We, BRITISH GAS CORPORATION, a British Statutory Body Corporate, of 59 Bryanston Street, London WIA 2 AZ, do hereby declare the invention, S for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following
statement:-
This invention relates to a method for removing water-soluble salts from refrigerated heat exchange surfaces.
This invention further relates to a method for removing water-soluble inorganic salts, organic materials and ice from refrigerated heat exchange surfaces.
In numerous industrial applications, heat exchange surfaces are used to cool streams which contain trace amounts of watersoluble inorganic salts, organic materials and water In such instances, the water, organic materials and inorganic salts tend to be precipitated onto the heat exchange surfaces when cooling is continued to temperatures below about 320 F.
Heretofore, methanol has been used to remove ice and organic materials from such surfaces as disclosed in U S Patent 2,863,527 issued December 9, 1958 to Herbert et al; however, the use of methanol in such instances does not remove watersoluble inorganic salts which in many instances are co-deposited with the ice As a result, it has been necessary to clean the heat exchange surfaces frequently.
It has now been found that such surfaces can be maintained in a clean servicable condition for substantially greater periods of time between cleaning by the use of a method for removing water-soluble inorganic salts, organic materials and ice from such refrigerated heat exchange surfaces wherein the method comprises contacting the surfaces with a methanolwater mixture containing at least about 20 weight percent methanol.
The Figure is a flow diagram of a heat exchange arrangement utilizing the method of the present invention.
The method of the present invention is useful with refrigerated heat exchange surfaces which operate at temperatures below 320 F ( O C) Such surfaces, when used to cool streams which contain water, minor amounts of water-soluble inorganic salts or compounds which react to form water-soluble inorganic salts and the like, are subject to fouling as ice and the salts are formed on the heat exchange surfaces One specific example of such an application comprises the use of methanol contacting to remove hydrogen sulfide, organic sulfur compounds such as COS, C 52, thiophene and mercaptans, carbon dioxide, water, NH 3, hydrocarbons and other catalyst contaminants or poisons from synthesis gas streams used in the production of methane by the reaction of carbon oxides and hydrogen The streams passed to the methanol contacting typically contain HS, CO, CO 2, H 2 O, COS, CS,, C 4 H 4 S, CH 4, HN 3, H 2, and in some instances, heavier hydrocarbon compounds.
In the methanol contacting, the HS, COS, CS,, C 4 H 4 S, CO,, HO, and heavier hydrocarbon compounds are removed to a substantial extent In most such applications, an effort is made to remove substantially all of these compounds from the synthesis gas stream which comprises primarily CO, CO,, H,, and CH 4 Obviously, the methanol contacting is at a low temperature and is typically conducted at temperatures of -40 F (-40 C) and below To conserve energy, the cold synthesis gas mixture produced as a result of the methanol contacting is passed to a heat exchanger where it is used as a heat exchange fluid to cool the incoming impure synthesis gas stream to temperatures below 320 F ( 00 C) and in some instances as low as -30 F (-35 C) The impure synthesis gas so cooled as indicated above contains water and minor amounts of ammonia and carbon dioxide which react according to the following equation.
CO 2 + HO+NH, s NH 4 HCO, ” 4 ( 11) 1 577 760 ( 19)) 2 1577,760 2 to form ammonium bicarbonate which is a water-soluble salt which deposits on the heat exchange surfaces Of course, ice also deposits upon the heat exchange surfaces.
S Heretofore, methanol has been used to remove the ice from the heat exchange surfaces It has been observed, however, that the use of methanol does not clean the heat exchange surfaces completely and it is necessary that the heat exchange surfaces be cleaned frequently by other means in order to maintain heat exchange efficiency.
It has now been found that the heat exchange surfaces in contact with such impure synthesis gas, can be maintained in operation for extended periods of time by the use of a methanol-water mixture for flushing the heat exchange surfaces The methanol-water mixture should contain at least 20 weight percent methanol and desirably, at least 40 weight percent methanol.
The use of mixtures containing insufficient water are less effective in removing water-soluble salts and the use of insufficient quantities of methanol results in a mixture which is less effective in removing organic materials and which tends to freeze on the heat exchange surfaces Thus it is preferred that the mixture contain from 20 to 70 weight percent methanol and especially desirable results have been obtained wherein the mixture contained from 40 to 60 weight percent methanol with the preferred composition being about 50 weight percent methanol Such mixtures have been found effective in removing the inorganic salt deposits, i e ammonium bicarbonate, ice and any heavier hydrocarbon materials which may have deposited on the heat exchange surfaces.
The use of such methanol-water mixtures has been found to be surprisingly effective in dissolving the limitedly water-soluble ammonium bicarbonate ( 11 9 grams per 100 ml of water of O C), the heavier hydrocarbons and ice The synergistic improvement achieved by the use of the methanol-water mixtures has resulted in an extended heat exchange surface life, and improved efficiency during operations.
The accompanying drawing is a schematic flowsheet of a methanol contact column and a heat exchanger wherein the method of the present invention is used A column 10, having a methanol inlet 12 and a methanol outlet 14 is shown Impure synthesis gas is charged to the lower portion of column 10 through an impure synthesis gas inlet 16 and the purified synthesis gas is recovered through a purified synthesis gas line 18 The impure synthesis gas is charged to column 10 after passage through a heat exchanger 20 via an inlet line 22 The heat exchanger is cooled by the flow of purified synthesis gas from line 18 The heat exchange surfaces are cleaned periodically by flushing with a methanol-water mixture through line 24 The methanol-water mixture is passed over the heat exchange surfaces in contact with the impure synthesis gas stream and forms a portion of the impure synthesis gas stream passing to column 10 through line 16 The methanol and water are both removed in the methanol column so that neither appears in the purified synthesis gas stream flowing through line 18 It is not necessary to contact the heat exchange surfaces in contact with the purified synthesis gas since substantially no water or carbon dioxide is contained therein Clearly the methanolwater flushing can be either periodic or continuous as required by the deposition rate of ice and inorganic fouling materials such as ammonium bicarbonate.

Claims (6)

WHAT WE CLAIM IS:-

1 A method of removing water-soluble inorganic salts from refrigerated heat exchange surfaces, the method consisting essentially of contacting said surfaces with a methanol-water mixture containing at least weight percent methanol.

2 The method of Claim I wherein said surfaces are intermittently flushed with said mixture to remove said salts.

3 The method of Claim I or Claim 2 wherein said mixture contains from 20 to 70 weight percent methanol.

4 The method of Claim 3 wherein said mixture contains at least 40 weight percent methanol.

The method of any one of the preceding Claims wherein said watersoluble salts comprise ammonium bicarbonate.

6 A method of removing water-soluble inorganic salts from refrigerated heatexchange surfaces according to Claim I and substantially as hereinbefore described.
Agent for the Applicants W WALLACE, Chartered Patent Agent.
Printed for Her Majesty’s Stationery Office, by the Courier Press, Leamington Spa, 1980 Published by The Patent Of Fice, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.
I 1,577,760

GB14148/77A
1977-04-04
1977-04-04
Clean heat exchangers

Expired

GB1577760A
(en)

Priority Applications (7)

Application Number
Priority Date
Filing Date
Title

GB14148/77A

GB1577760A
(en)

1977-04-04
1977-04-04
Clean heat exchangers

US05/847,981

US4167100A
(en)

1977-04-04
1977-11-02
Method for removing water-soluble inorganic salts and ice from heat exchange surfaces

CA295,318A

CA1106266A
(en)

1977-04-04
1978-01-19
Method for removing water-soluble inorganic salts and ice from heat exchanger surfaces

AU32716/78A

AU509657B2
(en)

1977-04-04
1978-01-25
Clearing heat exchange surfaces

ZA00780516A

ZA78516B
(en)

1977-04-04
1978-01-27
Method for removing water-soluble inorganic salts and ice from heat exchange surfaces

DE19782807223

DE2807223A1
(en)

1977-04-04
1978-02-20

METHOD FOR REMOVING WATER-SOLUBLE INORGANIC SALTS AND ICE

JP1865378A

JPS53122967A
(en)

1977-04-04
1978-02-22
Method of removing aqueous inorganic salts from heat exchanger surface of refrigerator

Applications Claiming Priority (1)

Application Number
Priority Date
Filing Date
Title

GB14148/77A

GB1577760A
(en)

1977-04-04
1977-04-04
Clean heat exchangers

Publications (1)

Publication Number
Publication Date

GB1577760A
true

GB1577760A
(en)

1980-10-29

Family
ID=10035888
Family Applications (1)

Application Number
Title
Priority Date
Filing Date

GB14148/77A
Expired

GB1577760A
(en)

1977-04-04
1977-04-04
Clean heat exchangers

Country Status (7)

Country
Link

US
(1)

US4167100A
(en)

JP
(1)

JPS53122967A
(en)

AU
(1)

AU509657B2
(en)

CA
(1)

CA1106266A
(en)

DE
(1)

DE2807223A1
(en)

GB
(1)

GB1577760A
(en)

ZA
(1)

ZA78516B
(en)

Family Cites Families (2)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

US2863527A
(en)

1949-09-15
1958-12-09
Metallgesellschaft Ag
Process for the purification of gases

US2686407A
(en)

1952-09-05
1954-08-17
Ansul Chemical Co
Method of elimination of refrigeration frost

1977

1977-04-04
GB
GB14148/77A
patent/GB1577760A/en
not_active
Expired

1977-11-02
US
US05/847,981
patent/US4167100A/en
not_active
Expired – Lifetime

1978

1978-01-19
CA
CA295,318A
patent/CA1106266A/en
not_active
Expired

1978-01-25
AU
AU32716/78A
patent/AU509657B2/en
not_active
Expired

1978-01-27
ZA
ZA00780516A
patent/ZA78516B/en
unknown

1978-02-20
DE
DE19782807223
patent/DE2807223A1/en
not_active
Withdrawn

1978-02-22
JP
JP1865378A
patent/JPS53122967A/en
active
Pending

Also Published As

Publication number
Publication date

AU509657B2
(en)

1980-05-22

AU3271678A
(en)

1979-08-02

US4167100A
(en)

1979-09-11

DE2807223A1
(en)

1978-10-12

CA1106266A
(en)

1981-08-04

JPS53122967A
(en)

1978-10-26

ZA78516B
(en)

1978-12-27

Contact information