Pre-fractionation of cracked gas or olefins fractionation by one or two mixed refrigerant loops and cooling water
First Claim
1. A process for partial condensation of a process gas which initially comprises significant amounts of methane and ethylene comprising:
- (a) a plurality of sequential. condensation and separation stages comprising, at each condensation and separation stage, condensation of at least part of the process gas and separation of the resulting condensate and remaining process gas; and
(b) supplying refrigeration for condensation at each condensation and separation stage by a first mixed refrigerant refrigeration loop, wherein a first mixed refrigerant used therein is comprised substantially of ethylene, ethane, and propylene and the relative proportions of those components remain constant through the first mixed refrigerant refrigeration loop.
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Abstract
The present invention is a plurality of stages for partial condensation and phase separation a process gas stream, preferably containing substantial amounts of light olefins, methane, and hydrogen, but containing initially at least substantial amounts of methane and ethylene. Each condensation and separation stage is refrigerated with a subcooled and flashed high pressure liquid of a mixed refrigerant refrigeration loop, wherein throughout the loop the relative component ratios of the mixed refrigerant components are constant, contrasted with the several mixed refrigerant processes of the prior art where for all the streams of each closed refrigeration loop. In addition, rectification and/or stripping sections of an ethylene separation train have a common support construction taking advantage of relatively similar column diameters to reduce the total number of columns in the process.
40 Citations
24 Claims
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1. A process for partial condensation of a process gas which initially comprises significant amounts of methane and ethylene comprising:
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(a) a plurality of sequential. condensation and separation stages comprising, at each condensation and separation stage, condensation of at least part of the process gas and separation of the resulting condensate and remaining process gas; and (b) supplying refrigeration for condensation at each condensation and separation stage by a first mixed refrigerant refrigeration loop, wherein a first mixed refrigerant used therein is comprised substantially of ethylene, ethane, and propylene and the relative proportions of those components remain constant through the first mixed refrigerant refrigeration loop. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A process for a thermally linked fractionation combination comprising:
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(a) an upper rectification section in a first pressure shell and a lower rectification section in a second pressure shell whereby an upper part of the lower rectification section pressure shell is supportively connected and located immediately inferior to a lower part of the upper rectification section pressure shell; (b) an upper rectification section stripping section is located in third pressure shell which is supported separately from than that of the pressure shell of the lower or upper rectification section; (c) the liquid bottom stage stream of the upper rectification section is divided between top stages of the lower rectification section and the upper rectification section stripping section for reflux and stripping feed respectively; and (d) top stage vapor streams from the lower rectification section and the upper rectification section stripping section are combined and introduced to the bottom stage of the upper rectification section to provide stripping vapor. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A process for partial condensation of a process gas which initially comprises significant amounts of methane and ethylene comprising:
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(a) a plurality of sequential condensation and separation stages comprising, at each condensation and separation stage, condensation of at least part of the process gas and separation of the resulting condensate and remaining process gas, providing the resulting condensate for use as at least part of the refluxing liquid to rectification stages for the process gas; and (b) supplying refrigeration for condensation at each condensation and separation stage by a first mixed refrigerant refrigeration loop, wherein a first mixed refrigerant used therein is comprised substantially of ethylene, ethane, and propylene and the relative proportions of those components remain constant through the first mixed refrigerant refrigeration loop. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification