Catalytic two-stage liquefaction of coal utilizing cascading of used

Abstract

A multi-stage catalytic process for hydrogenation and liquefaction of coal using ebullated-bed catalytic reactors to produce low-boiling hydrocarbon liquid products, in which used catalyst is removed from a lower temperature first stage reactor operating at temperature not exceeding about 800.degree. F. and cascaded forward to a higher temperature second stage reactor for further use therein. Reaction conditions in the first stage reactor are preferably 700.degree.-800.degree. F. temperature, 1000-4000 psig hydrogen partial pressure, and a coal feed rate of 10-90 lb coal/hr per ft.sup.3 catalyst settled volume in the reactor. Useful higher temperature or second stage reaction conditions are 750.degree.-850.degree. F. temperature, and 1000-4000 psig hydrogen partial pressure. The used catalyst withdrawn from the lower temperature of first stage reactor has a catalyst age of 300-3000 lb coal proceses/lb fresh catalyst, and is transferred forward to the higher temperature second stage reactor for further use to catalyst age of 1000-6000 lb coal processed per lb fresh catalyst. If desired, a higher temperature third catalytic reactor can be provided and used catalyst from the second stage reactor cascaded forward into the third reactor for further use therein. Useful catalysts include metal oxides of cobalt, iron, molybdenum, nickel, tin, or tungsten deposited on a base of alumina, magnesia, silica, or titania, with cobalt moly and nickel moly on alumina catalyst being preferred. This process advantageously requires a smaller quantity of fresh catalyst per ton of coal processed to produce the low-boiling hydrocarbon liquid products.