Exxon Research and Engineering Company

John Ernest Asplin

Gordon Frederick Stuntz

William A Wachter

Paul K Ladwig

Tan-Jen Chen

Brian Erik Henry

Shun Chong Fung

George A Swan, Iii

Marcel Johannes Janssen

Michael Walter Bedell

Brian Eric Henry

A process for selectively producing C.sub.2 -C.sub.4 olefins from a catalytically cracked or thermally cracked naphtha stream is disclosed. A mixture of the naphtha stream and a stream of steam is feed into a reaction zone where it is contacted with a catalyst containing from about 10 to 50 wt. % of a crystalline zeolite having an average pore diameter less than about 0.7 nanometers at reaction conditions which include temperatures from about 500 to 650.degree. C. and a hydrocarbon partial pressure from about 10 to 40 psia.

Process for selectively producing light olefins in a fluid catalytic

C.sub.2 to C.sub.4 olefins are selectively produced from a gas oil or resid in a two stage process. The gas oil or resid is reacted in a first stage comprised of a fluid catalytic cracking unit wherein it is converted in the presence of conventional large pore zeolitic catalyst to reaction products, including a naphtha boiling range stream. The naphtha boiling range stream is introduced into a second stage comprised of a process unit containing a reaction zone, a stripping zone, a catalyst regeneration zone, and a fractionation zone. The naphtha feedstream is contacted in the reaction zone with a catalyst containing from about 10 to 50 wt. % of a crystalline zeolite having an average pore diameter less than about 0.7 nanometers at reaction conditions which include temperatures ranging from about 500 to 650.degree. C. and a hydrocarbon partial pressure from about 10 to 40 psia. Vapor products are collected overhead and the catalyst particles are passed through the stripping zone on the way to the catalyst regeneration zone. Volatiles are stripped with steam in the stripping zone and the catalyst particles are sent to the catalyst regeneration zone where coke is burned from the catalyst, which is then recycled to the reaction zone.

Two stage fluid catalytic cracking process for selectively producing     b.

A process for selectively producing C.sub.3 olefins from a catalytically cracked or thermally cracked naphtha stream. The naphtha stream is introduced into a process unit comprised of a reaction zone, a stripping zone, a catalyst regeneration zone, and a fractionation zone. The naphtha feedstream is contacted in the reaction zone with a catalyst containing from about 10 to 50 wt. % of a crystalline zeolite having an average pore diameter less than about 0.7 nanometers at reaction conditions which include temperatures ranging from about 500.degree. to 650.degree. C. and a hydrocarbon partial pressure from about 10 to 40 psia. Vapor products are collected overhead and the catalyst particles are passed through the stripping zone on the way to the catalyst regeneration zone. Volatiles are stripped with steam in the stripping zone and the catalyst particles are sent to the catalyst regeneration zone where coke is burned from the catalyst, which is then recycled to the reaction zone. Overhead products from the reaction zone are passed to a fractionation zone where a stream of C.sub.3 's is recovered and a stream rich in C.sub.4 and/or C.sub.5 olefins is recycled to the stripping zone.

Process for selectively producing C3 olefins in a fluid catalytic

A process for selectively producing C.sub.2 -C.sub.4 olefins from a catalytically cracked or thermally cracked naphtha stream. The naphtha stream is contacted with a catalyst containing from about 10 to 50 wt. % of a crystalline zeolite having an average pore diameter less than about 0.7 nanometers at reaction conditions which include temperatures from about 500 to 650.degree. C. and a hydrocarbon partial pressure from about 10 to 40 psia.

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Southhampton, United Kingdom

John Ernest Asplin