The present invention relates to process and apparatus for separating out ash and residue from a high pressure fuel gasifying reactor in the pressure from atmospheric pressure to 80 bar and gasifying temperature of 800-1800 deg.c. The fuel may be coal, coke, ash containing liquid or liquid-solid suspension. The high pressure fuel gasifying reactor has one gasifying chamber, one shock chamber, one residue separating chamber, and one water circulating device to loosen residue and to provide water to the shock chamber.