Dehydrogenation separation unit with mixed refrigerant cooling

Abstract

A system for separating olefinic hydrocarbon and hydrogen in an effluent fluid stream from a dehydrogenation reactor includes a heat exchanger that receives and partially condenses the effluent fluid stream so that a mixed phase effluent stream is formed. A primary separation device receives and separates the mixed phase effluent stream into a primary vapor stream and a primary liquid product stream. A heat exchanger receives and partially condenses the primary vapor stream so that a mixed phase primary stream is formed. A secondary separation device receives and separates the mixed phase primary stream into a secondary vapor stream and a secondary liquid product stream. A heat exchanger receives and warms the secondary vapor stream to provide refrigeration for partially condensing the effluent fluid stream and a heat exchanger receives and warms the secondary vapor stream to provide refrigeration for partially condensing the primary vapor stream. A mixed refrigerant compression system provides refrigerant to a heat exchanger to provide refrigeration.

Description

[0001] priority claim [0002] This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 743,263, filed October 9, 2018, the contents of which are incorporated herein by reference. Background technique [0003] Propane dehydrogenation (PDH) separation systems are known in the art. An example of such a system is described in commonly owned US Patent No. 6,333,445, the contents of which are incorporated herein by reference. [0004] Current designs for PDH separation systems call for the reactor effluent vapor stream to be compressed to high pressure (~12 Barg) using a reactor effluent compressor and then decompressed using two generator-braked or compressor-braked cryogenic turboexpanders, This provides the refrigeration required for the separation and recovery of liquid olefin products. [0005] Disadvantages of such prior art systems include power consumption of the overall process, increased cost and maintenance requirements of the turbo...

AI Technical Summary

Problems solved by technology

[0005] Disadvantages of such prior art systems include power consumption of the overall process, increased cost and maintenance requirements of the turboexpander / generator (or compressor) package, high demanded reactor effluent compressor discharge pressure (which increases capital and operating costs) and lack of flexibility to significantly adjust olefin and hydrogen separation temperatures

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