C6 recycle for propylene generation in a fluid catalytic cracking unit

Abstract

The present invention relates to a process for selectively producing C3 olefins from a catalytically cracked or thermally cracked naphtha stream. The process is practiced by recycling a C6 rich fraction of the catalytic naphtha product to the riser upstream the feed injection point, to a parallel riser, to the spent catalyst stripper, and / or to the reactor dilute phase immediately above the stripper.

Description

field of invention [0001] The present invention relates to the selective production of C from catalytically cracked or thermally cracked naphtha streams in a fluidized bed catalytic process unit 3 Alkenes method. By converting the C-rich product of the catalytic naphtha 6 The process is carried out by recycling the fraction to a riser upstream of the feed injection point, a riser downstream of the feed injection point, a parallel riser, a spent catalyst stripper, and / or a reactor dilute phase immediately above the stripper. Background of the invention [0002] The need for low emission fuels has created an increased demand for light olefins used in the alkylation, oligomerization, methyl tert-butyl ether and ETBE synthesis processes. In addition, there is a continuing need for the low-cost supply of light olefins, especially propylene, as feedstock for the production of polyolefins, especially polypropylene. [0003] Fixed bed processes for the dehydrogenation of light al...

AI Technical Summary

Problems solved by technology

Additionally, even though a specific catalyst balance can be maintained to maximize overall olefin production relative to fuel, olefin selectivity is often low due to undesired side reactions such as extensive cracking, isomerization, aromatization, and hydrogen transfer reactions

Increased cost of recovering the desired light olefins due to the production of light saturated gases from undesired side reactions

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