Synthesis gas from solid carbonaceous fuel

A process for producing synthesis or fuel gas mixtures from solid carbonaceous fuels comprising:

• 1. mixing together to produce a substantially water free pumpable slurry, a liquid CO.sub.2 -rich stream and a solid carbonaceous fuel having a particle size such that 100% of the material passes through an ASTM E 11-70 Sieve Designation Standard 425 .mu.m (Alternative No. 40) and at least 80% passes through an ASTM E 11-70 Sieve Designation Standard 75 .mu.m (Alternative No. 200), in a mixing zone at a temperature in the range of above about -69.degree. to 80.degree.F. and a pressure in the range of above about 76 p.s.i.a. to 4500 psia. and wherein the weight ratio of CO.sub.2 to solid carbonaceous fuel is in the range of about 0.6 to 2.0;
• 2. preheating the mixture from (1) to a temperature in the range of about 100.degree. to 900.degree.F. to produce a dense phase gas-liquid dispersion of solid carbonaceous fuel in CO.sub.2 carrier;
• 3. reacting the dispersion from (2) with a free-oxygen containing gas selected from the group consisting of air, oxygen-enriched air (greater than 21 mole % O.sub.2), and substantially pure oxygen (greater than 95 mole % O.sub.2) in the reaction zone of a free-flow noncatalytic gas generator at an autogenous temperature in the range of about 1200.degree. to 3000.degree.F. and a pressure in the range of above about 30 to 4400 psia, to produce an effluent gas stream comprising a mixture of gases from the group CO, CO.sub.2, H.sub.2, H.sub.2 O, CH.sub.4, H.sub.2 S, COS, N.sub.2, A, and mixtures thereof, and containing entrained solid particles;
• and wherein the ratio of atoms of oxygen in the free-oxygen containing gas plus atoms of organically combined oxygen in the solid carbonaceous fuel to the atoms of carbon in the carbonaceous fuel is in the range of about 0.7 to 1.6;
• 4. cooling and cleaning the effluent gas stream from (3) and separating said entrained solid particles to produce a clean process gas stream;
• 5. increasing the H.sub.2 /CO mole ratio of the clean process gas stream from (4) by subjecting at least a portion of said process gas stream to the water-gas shift reaction;
• 6. purifying and separating the process gas stream from (5) in a gas purification and separation zone into the following gaseous streams:
• (a) a dry CO.sub.2 -rich stream substantially comprising CO.sub.2 and minor amounts of H.sub.2 S and COS impurities, (b) optionally, a vent stream substantially comprising CO.sub.2 and a trace of H.sub.2 S, (c) a dry H.sub.2 S-rich gaseous stream substantially comprising the remainder of all of the H.sub.2 S produced, substantially all of the COS produced and CO.sub.2, and (d) a dry product gas stream comprising gases selected from the group consisting of CO, H.sub.2, CH.sub.4, A, N.sub.2, and mixtures thereof;
• 7. liquefying the dry CO.sub.2 -rich stream (6) (a) in a gas liquefication zone;
• and
• 8. introducing at least a portion of said liquid CO.sub.2 -stream from (7) into (1) as said liquid CO.sub.2 -rich stream.