Method for controlling a recycle gas stream utilizing an ejector for the cooling of a unit operation
AssigneePraxair Technology, Inc.
InventorsWilliam J Scharmach, Richard M Kelly, Mohammad Abdul-Aziz Rashad, Yi Ma Lenhert, Matthew Thomas
Life of this patent
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Abstract
The present invention relates to a method of preparing a gas coolant for the direct cooling of a unit operation under a fixed heat load from its normal operating temperature (e.g., 300° F. and above) to a lower temperature (e.g., below 100° F.) in order to allow for maintenance or other non-routine work to be carried out in said unit operation.
Claims12
A method for direct cooling of a unit operation with a combination of a vaporized motive fluid stream and at least a portion of an effluent gas stream from the unit operation, wherein the direct cooling method comprises:
- a. circulating a portion of said effluent gas stream from the unit operation with one or more non-mechanical pumps where the vaporized motive fluid stream is provided as a motive force wherein said unit operation is under a fixed heat load having a temperature in the range of 300 to 500° F.;
- b. providing the vaporized motive fluid stream to the one or more non-mechanical pumps at a temperature in the range of −452° F. to 50° F.;
- c. forming a cooling stream by combining said effluent gas stream from the unit operation and the vaporized motive fluid in the one or more non-mechanical pumps, wherein the cooling stream has a temperature in the range of −50° F. to 300° F.;
- d. adjusting a recycle ratio of mass flow rates of said effluent gas stream from the unit operation to the vaporized motive fluid stream combined in the one or more non-mechanical pumps wherein the recycle ratio is determined by:
- Recycle
-
-
- Ratio
- mass
- =
- C
- Mot
- *
- (
- T
- C
- -
- T
- Mot
- )
- C
- Eff
- *
- (
- T
- Eff
- -
- T
- C
- )
- where,
- the Recycle Ratiomass is the ratio of the mass flow rate of the effluent to the mass flow rate of the vaporized motive fluid stream;
- CMot is the specific heat of the vaporized motive fluid stream;
- CEff is the specific heat of the unit operation effluent stream entering the one or more non-mechanical pumps;
- TC is the temperature of the cooling stream or a target temperature of the cooling stream exiting the one or more non-mechanical pumps;
- TMot is the temperature of the vaporized motive fluid stream, and is selected by the operator;
- TEff is the temperature of the unit operation effluent stream entering the one or more non-mechanical pumps;
- and
- direct cooling of said unit operation under the fixed heat load to a lower temperature by routing the cooling stream to the unit operation.
Dependencies are inferred from the claim text.