Gasification of low quality solid fuels

Claim 1

A process for the gasification of a solid carbonaceous fuel selected from the group consisting of sub-bituminous coal and lignite which comprises forming an initial slurry of said fuel in water, containing less than 50 weight percent solids, contacting said initial slurry with hot synthesis gas comprising carbon monoxide and hydrogen in a quench zone thereby cooling said gas and heating said initial slurry to a temperature between about 400° F. and 700° F., the pressure in said quench zone being sufficiently high to keep the water in liquid phase, maintaining the slurry under said conditions of temperature and pressure for a period of time between 0.1 minute and 1 hour, subjecting the so treated fuel as a concentrated water slurry containing between about 50 and 75 wt. % solids measured on a dry basis to partial oxidation to produce additional synthesis gas comprising carbon monoxide and hydrogen and introducing said additional synthesis gas into said quench zone to heat additional initial slurry and quench said additional synthesis gas.