Increased liquid sensitivity during fischer-tropsch synthesis by olefin incorporation

Abstract

An integrated process for producing liquid fuels from syngas via a two-stage Fischer-Tropsch reaction is disclosed. The first stage of the Fischer-Tropsch chemistry is performed using conditions in which chain growth probabilities are relatively low to moderate, and the product of the reaction includes a relatively high proportion of low molecular (C,) weight olefins and a relatively low proportion of high molecular weight (C,+) waxes. The product from the first stage is fed into the second stage where the chain growth probabilities are relatively high. The wax and other paraffins produced in the first reaction are largely inert under these conditions. The light olefins compete with heavier olefins for chain initiation, and fewer chains will be initiated at C,+. With most chains initiated at C,, moderate chain growth probability will produce a relatively larger fraction in the C,range. In this manner, wax yield is minimized.