Abstract

A novel ethylene and propylene production technology, Catalytic Pyrolysis Process (CPP), has been developed by Research Institute of Petroleum Processing, SINOPEC on the basis of modification of DCC process via operating parameter, catalyst formulation and unit configuration. CPP is suitable for processing heavy feedstocks, such as VGO, VGO blended with residual oil, coker gas oil, deasphalted oil, and atmospheric residue, etc. A riser reactor and a specially designed zeolite catalyst are used in this technology. Both catalytic and thermal reactions take place on the dual-functional catalyst with carbonium ion and free radical reaction mechanism.

Based on a great deal investigation from lab to pilot plant test, a commercial CPP unit with 80kt/a capacity was revamped from a DCC unit and the test was conducted in the last quarter of 2000 to early 2001 cooperated with SINOPEC Engineering Incorporation and PetroChina Daqing Refining & Chemical Company. The commercial results showed that 20.37wt% ethylene and 18.23wt% propylene were obtained under a reaction temperature of 913K with Daqing atmospheric residue as feedstock.

CPP technology introduced some new engineering devices including quenching outlet reactants and heat recovery facilities, and paves a novel way to producing ethylene and propylene from heavy feedstock.

Introduction

Ethylene is the most important petrochemical raw material. Its production technology is the well known steam cracking with light hydrocarbons, such as ethane, propane, butane, naphtha and light gas oil as feedstocks. The proportion of various feedstocks worldwide is shown in Fig 1. Among these feedstocks, naphtha is the dominant one which amounts to 50~55% of the total steam cracking feedstocks. In North American and Middle East, ethane is used as a preferable feedstock which accounts for 25~30% of the total. The other feedstocks, such as propane, butane, light gas oil and condensate are less than 10%.

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COMMERCIAL TRIAL OF CATALYTIC PYROLYSIS PROCESS FOR MANUFACTURING ETHYLENE AND PROPYLENE

Butane Propane Naphtha Ethane Other LGO Figure 1: Proportion of various feedstocks in steam cracking Propylene is second of importance only after ethylene as a raw material for petrochemical industries. Today about 70% of the global propylene is produced by steam cracking with light hydrocarbon feedstock. Most of the remaining propylene is recovered from FCC and Deep Catalytic Cracking (DCC), and a small amount by propane dehydrogenation and other processes.

In recent years, great attention has been paid to the technologies producing ethylene using heavy feedstocks. A series of FCC family technologies1, such as DCC for maximum p

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