Core-in-shell heat exchangers for multistage compressors
First Claim
1. Apparatus for cooling a normally gaseous feed stream, comprising:
- (a) a multistage compressor having at least a high-stage section and a low-stage section;
(b) heat exchange means for condensing refrigerant gas compressed in said multistage compressor to produce a liquid refrigerant;
(c) an elongated high-stage heat exchange shell associated with said high-stage section of said multistage compressor, said high-stage heat exchange shell having a volume sufficient for handling vapor-compression refrigeration service for said high-stage compressor section, and additionally having a surge volume;
(d) at least one high-stage plate-fin-core disposed in said high-stage shell, said core being operable over a range of liquid levels in said high-stage shell;
(e) a baffle plate transversely disposed in said high-stage shell so as to facilitate maintenance of a minimum liquid level for said plate fin core;
(f) means for flashing said liquid refrigerant into said high-stage shell and producing a first mixture of gas and liquid in which said feed gas stream passes in indirect heat exchange through said high-stage plate-fin-core;
(g) means for separating said first mixture of gas and liquid and providing said gas to an inlet of said high-stage compressor section, and holding sufficient liquid in said high-stage shell to provide at least a minimum functional liquid level for said high-stage core;
(h) an elongated low-stage heat exchange shell associated with said low-stage section of said multistage compressor, said low-stage heat exchange shell containing at least one low-stage plate-fin-core, said low-stage shell having a volume sufficient for handling vapor-compression refrigeration service for said low-stage compressor section;
(i) means for flashing said liquid refrigerant withdrawn from said surge volume into said low-stage shell to produce a second mixture of gas and liquid in which said feed gas stream passes in indirect heat exchange through said low-stage plate-fin-core;
(j) means for separating said second mixture of gas and liquid in said low-stage shell and providing said gas to an inlet of said low-stage compressor section and holding sufficient liquid in said low-stage shell to provide at least a minimum functional liquid level for said low-stage core; and
(k) wherein said surge volume in said high-stage shell is a volume equal to a level fluctuation in said low-stage shell of about four inches to about eight inches.
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Accused Products
Abstract
In multistage refrigeration compression, where liquid refrigerant withdraw from a core-in-shell type heat exchanger connected to a high compression stage is passed to a similar exchanger connected to a lower compression stage, liquid level stability in the higher compression stage exchanger is improved by providing an enlarged surge volume. A baffle plate transversing a lower portion of the shell divides the shell into a cooling zone that contains the cores, and a discharge zone that is part of the surge volume. The height of the baffle is selected to facilitate maintenance of at least a minimum functional liquid level in the shell. Liquid refrigerant withdraw from the discharge zone of the high-stage shell is supplied to the cooling zone of a shell connected to a lower compression stage. The liquid level in the shell is maintained by manipulating flow to liquid refrigerant that is flashed into the cooling zone of the higher compression stage shell. A refrigerant compressor may employ two or more compression stages, where the higher stage shells are typically much smaller than the lower stage shells, and the described scheme prevent major liquid level upsets in the shell of a higher stage resulting from minor liquid level upsets in the lower stage shells.
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Citations
14 Claims
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1. Apparatus for cooling a normally gaseous feed stream, comprising:
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(a) a multistage compressor having at least a high-stage section and a low-stage section; (b) heat exchange means for condensing refrigerant gas compressed in said multistage compressor to produce a liquid refrigerant; (c) an elongated high-stage heat exchange shell associated with said high-stage section of said multistage compressor, said high-stage heat exchange shell having a volume sufficient for handling vapor-compression refrigeration service for said high-stage compressor section, and additionally having a surge volume; (d) at least one high-stage plate-fin-core disposed in said high-stage shell, said core being operable over a range of liquid levels in said high-stage shell; (e) a baffle plate transversely disposed in said high-stage shell so as to facilitate maintenance of a minimum liquid level for said plate fin core; (f) means for flashing said liquid refrigerant into said high-stage shell and producing a first mixture of gas and liquid in which said feed gas stream passes in indirect heat exchange through said high-stage plate-fin-core; (g) means for separating said first mixture of gas and liquid and providing said gas to an inlet of said high-stage compressor section, and holding sufficient liquid in said high-stage shell to provide at least a minimum functional liquid level for said high-stage core; (h) an elongated low-stage heat exchange shell associated with said low-stage section of said multistage compressor, said low-stage heat exchange shell containing at least one low-stage plate-fin-core, said low-stage shell having a volume sufficient for handling vapor-compression refrigeration service for said low-stage compressor section; (i) means for flashing said liquid refrigerant withdrawn from said surge volume into said low-stage shell to produce a second mixture of gas and liquid in which said feed gas stream passes in indirect heat exchange through said low-stage plate-fin-core; (j) means for separating said second mixture of gas and liquid in said low-stage shell and providing said gas to an inlet of said low-stage compressor section and holding sufficient liquid in said low-stage shell to provide at least a minimum functional liquid level for said low-stage core; and (k) wherein said surge volume in said high-stage shell is a volume equal to a level fluctuation in said low-stage shell of about four inches to about eight inches. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for cooling a normally gaseous material which comprises the step of providing a process stream of said normally gaseous material to an apparatus comprising:
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(a) a multistage compressor having at least a high-stage section and a low-stage section; (b) a heat exchange means for condensing refrigerant gas compressed in said multistage compressor to produce a liquid refrigerant; (c) an elongated high-stage heat exchange shell associated with said high-stage section of said multistage compressor, said high-stage heat exchange shell having a volume sufficient for handling vapor compression refrigeration service for said high-stage compressor section, and having a surge volume; (d) at least one high-stage plate-fin-core, said core being operable over a range of liquid levels in said high-stage shell; (e) a baffle plate transversely disposed in said high-stage shell to facilitate maintenance of a minimum liquid level for said high-stage plate-fin-cores; (f) means for flashing said liquid refrigerant into said high-stage shell to produce a first mixture of gas and liquid in which said feed gas stream passes in indirect heat exchange through said high-stage plate-fin-core; (g) means for separating said first mixture of gas and liquid and providing said gas to an inlet of said high stage compressor section, and holding sufficient liquid in said high-stage shell to provide at least a minimum functional liquid level for said high-stage core; (h) an elongated low-stage heat exchange shell associated with said low-stage section of said multistage compressor, said low-stage heat exchange shell containing at least one low-stage plate-fin-core, said low-stage shell having a volume sufficient for handling the vapor- compression refrigeration service for said low-stage compressor section; (i) means for flashing said liquid refrigerant withdrawn from said surge volume into said low-stage shell to produce a second mixture of gas and liquid in which said feed gas stream passes in indirect heat exchange through said low-stage plate-fin-core; (j ) means for separating said second mixture of gas and liquid in said low-stage shell and providing said gas to an inlet of said low-stage compressor section and holding sufficient liquid to provide a level in said low-stage shell; and (k) wherein said surge volume in said high-stage shell is a volume equal to a level fluctuation in said low-stage shell of about four inches to about eight inches. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification