Two stage fluid catalytic cracking process for selectively producing b. C.su2 to C.sub.4 olefins

US6106697A · kind A · utility

Assignee

• Exxon Research and Engineering Company · US

Inventors

• George A. Swan, III · Baton Rouge, US
• Michael W. Bedell · Baton Rouge, US
• Paul K. Ladwig · Dover, US
• John E. Asplin · Houston, US
• Gordon F. Stuntz · Baton Rouge, US
• William A. Wachter · Baton Rouge, US
• Brian Erik Henry · Baton Rouge, US

Key dates

• Filing date: May 5, 1998
• Grant date: Aug 22, 2000
• Expiry date: May 5, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C10G2400/20
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

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 catal…