Texaco Inc.

William L Lafferty, Jr

Edward T Child

Robert M Suggitt

Frederick C Jahnke

Motasimur R Khan

Pumpable aqueous slurries of low rank coal e.g. subbituminous coal and lignite having a comparatively high solids content are made by keeping the particles of coal in contact with a non-oxidizing gas e.g. nitrogen and/or CO.sub.2 thereby maintaining a hydrophobic surface on the particles of coal while they are ground and dried, contacted with an aqueous slurry of liquid hydrocarbonaceous fuel which is absorbed and which coats the particles of coal, and then dried. The dried coated particles of low rank coal are mixed with water to produce a pumpable slurry having a solids content in the range of about 50 to 60 wt. %. In one embodiment, at least a portion of the water needed to produce said pumpable slurry is derived by cooling and condensing out water from the non-oxidizing gas that was used to dry the low rank coal. In still another embodiment, the dewatered non-oxidizing gas is introduced into the combustor of a gas turbine to moderate the temperature and thereby reduce the formation of NO.sub.x gases.

Partial oxidation of low rank coal

Mechanical and electrical power are produced along with synthesis or fuel gas by the partial oxidation process with integrated combustion and steam turbines. By-product vaporized liquefied natural gas for feed to a pipeline for gas consumers is obtained by heat exchange with heat containing streams from the partial oxidation gasification and gas cleaning and purification zone; and optionally from heat containing streams from combustion and/or steam turbine zones which are integrated with the partial oxidation process. Heat from the combustion turbine exhaust gas is used as follows: (1) superheat steam for use in a steam turbine; (2) preheat water saturated clean sulfur-free synthesis or fuel gas with or without supplemental methane enrichment; (3) preheat oxygen gas for the partial oxidation zone; and (4) vaporize LNG. Pre, inter, and after stages of an air compressor are cooled by indirect heat exchange with LNG which is thereby warmed or vaporized.

Combined power cycle with liquefied natural gas (LNG) and synthesis or

Mechanical and electrical power are produced along with synthesis or fuel gas by the partial oxidation process with integrated combustion and steam turbines. By-product vaporized liquefied natural gas for feed to a pipeline for gas consumers is obtained by heat exchange with heat containing streams from the partial oxidation gasification and gas cleaning and purification zone; and optionally from heat containing streams from combustion and/or steam turbine zones which are integrated with said partial oxidation process. Heat from the combustion turbine exhaust gas is used as follows: (1) superheat steam for use in a steam turbine; (2) preheat water saturated clean sulfur-free synthesis or fuel gas with or without supplemental methane enrichment; (3) preheat oxygen gas for said partial oxidation zone; and (4) vaporize LNG. Pre, inter, and after stages of an air compressor are cooled by indirect heat exchange with LNG which is thereby warmed or vaporized.

Cryogenic liquefied natural gas (LNG) is used as a source of refrigeration and methane in the production of dry sulfur-free, methane-enriched synthesis gas or fuel gas. Raw syngas is indirectly and directly contacted with cryogenic liquefied natural gas (LNG) and cooled thereby below the dew point. Water is thereby condensed out and separated from the process gas stream. Further, the liquid LNG vaporizes and increases the methane content of the dewatered synthesis gas. Cold liquid absorbent solvent contacts the dry CH.sub.4 -enriched synthesis gas in an absorption column and absorbs the acid gases e.g. H.sub.2 S and COS and optionally H.sub.2 S+COS+CO.sub.2. In a preferred embodiment, the rich solvent absorbent is regenerated in a stripping column and the released acid gases are sent to a Claus unit for the production of elemental sulfur. In a second embodiment, the regenerated lean liquid absorbent solvent may be mixed with the dry, purified synthesis gas leaving from the top of the absorption tower. This mixture is then directly and optionally indirectly contacted with additional cryogenic liquid LNG. The CH.sub.4 content of the synthesis or fuel gas is thereby increased to a value in the range of about 10 to 80 mole %. By means of a decanter, dry, sulfur-free methane-enriched syngas product is separated from liquid absorbent solvent. The liquid absorbent solvent is then recycled to the absorption column.

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Hopewell Junction, NY, United States of America

William L Lafferty, Jr