Coking of heavy feedstocks

Abstract

Abstract The formation of char in fluid coking is inhibited by the presence of hydrogen-donor compounds in the fluid coking zone, increasing the yield of desirable liquid products. A hydrogendonor solvent is admixed with a heavy fluid coker feedstock in amounts sufficient to provide at least 10 weight percent of hydrogen-donor compounds, based on total feed to the fluid coker. Preferable compounds for use as hydrogen donors are the partially saturated hydroaromatic compounds such as indane, C10-C12 tetralins, C12 and C13 acenaphthenes, di-, tetra-, and octahydroanthracene, and tetrahydroacenaphthene. The process is particularly useful in the production of liquid hydrocarbon products from solid coal wherein the coal is subjected to solvent liquefaction and the resulting liquid slurry is fed into a fluid-coking zone. Where hydrogen-donor solvent is used for the liquefaction step, and it does not become completely hydrogen-depleted, no additional solvent need be added prior to fluid coking. However, additional hydrogen-donor solvent may be added (and if not nondonor solvent was used in liquefaction, must be added) prior to such coking. The use of additional hydrogendonor solvent further enhances the yield of liquid products and inhibits char yield. Preferably, the fluid-coking step will be used in conjunction with an external burner, and a portion of the product coke will be removed for use in generating hydrogen by contact with steam, with such hydrogen being used to satisfy at least in part the demands for hydrogen in the hydrogenation of the recycle solvent.

Inventors

• 👤 Edward L Wilson Jr
• 👤 Jacob B Angelo

Bibliographic Details