Texaco Inc.

Texaco Development Corporation

Edward T Child

Albert Brent

George N Richter

William B Crouch

Charles P Marion

Blake Reynolds

James R Muenger

Robert M Suggitt

William L Lafferty, Jr

Frederick C Jahnke

Motasimur R Khan

Allen M Robin

Peter L Paull

Warren G Schlinger

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

Abundant low cost low rank coal may now be gasified by partial oxidation or burned in a furnace or boiler. About 30 to 45 parts by wt. of comminuted low rank coal is mixed and reacted in the reaction zone of a partial oxidation gas generator with a free-oxygen containing gas and (a) about 1 to 3 parts by wt. of a residual fuel oil, and (b) about 70 to 55 parts by wt. of water. The hot effluent stream of synthesis gas, reducing gas or fuel gas from the partial oxidation gasifier may be purified to provide a gas stream which will not pollute the environment.

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.

Process for producing dry, sulfur-free, CH.sub.4 -enriched synthesis or

A control system for a partial oxidation process for continuously producing synthesis gas, fuel gas or reducing gas in which process one fuel is replaced by a different fuel without shutting down or depressurizing the gas generator. This multifuel process is not tied to one particular fuel and reacts slurries of solid carbonaceous fuel and/or liquid or gaseous hydrocarbonaceous fuels. Problems of fuel availability are reduced due to the wide selection of fuels that are suitable for the subject process. A two-section burner having a high turndown feature is employed that comprises a central conduit; a central bunch of tubes positioned in said central conduit; an outer conduit coaxial with said central conduit and forming an annular passage therewith; and an annular bunch of tubes positioned in said annular passage. The downstream ends of said central and/or annular bunches of tubes are respectively retracted upstream from the burner face a distance of about 0 to 12 i.e. 3 to 10 times the minimum diameter of the central exit orifice and the minimum width of the annular exit orifice. A control system is provided for switching the type of reactant fuel streams flowing through either one or both sections of the burner. The flow rates of the oxidant, fuel, and temperature moderator streams may also be varied in either one or both sections of the burner, thereby effecting a rapid turndown or turnup of the burner and a change in the production of the effluent gas.

Partial oxidation system

A partial oxidation control system for continuously producing synthesis gas, fuel gas or reducing gas in which one process fuel is replaced by a different fuel without shutting down or depressurizing the gas generator. Suitable burners for introducing the feedstreams into the gas generator comprise a central conduit means radially spaced from a concentric coaxial outer conduit having a downstream exit nozzle, and providing a coaxial annular passage means therebetween. The central conduit means may be retracted upstream from the burner face a distance of about 0 to 12 and preferably 3 to 10 times the minimum diameter of the central exit orifice. A premix zone is preferably provided comprising one or more, say 2 to 5 coaxial chambers in series where substantial mixing of the reactant streams and optionally volatilization of the slurry medium takes place. A control system is provided for switching the type of reactant fuel stream flowing through either the central conduit means or the annular passage means of the burner and adjusting the flow rates of the reactant stream of free-oxygen containing gas with or without mixture with a temperature moderator and if necessary to introduce supplemental H.sub.2 O into the reaction zone to maintain the temperature and weight ratio H.sub.2 O/fuel in the reaction zone at design conditions for the partial oxidation reaction without stopping production of the product gas.

Synthesis gas is produced by partial oxidation of slurried coal followed by separation of ash, the temperature of the gas being thereafter controlled to permit a desired portion thereof to be directly contacted with water to achieve a gas/stream mixture of predetermined composition prior to shift conversion, the other portion being preferably convectively cooled for maximum thermal efficiency and then scrubbed prior to withdrawal as carbon monoxide-containing product.

Process for gasifying solid carbon containing materials

A burner and partial oxidation process for producing synthesis gas, fuel gas or reducing gas from slurries of solid carbonaceous fuel and/or liquid or gaseous hydrocarbon fuel. The burner has a high turndown feature and comprises a central conduit; a central bunch of parallel tubes that extend longitudinally through said central conduit; an outer conduit coaxial with said central conduit and forming an annular passage therewith; and an annular bunch of parallel tubes that extend longitudinally through said annular passage; and wherein the downstream ends of said central and annular bunches of parallel tubes are respectively retracted upstream from the burner face a distance of about 0 to 12 i.e. 3 to 10 times the minimum diameter of the central exit orifice and the minimum width of the annular exit orifice. Three ranges of flow through the burner may be obtained by using one or both bunches of tubes and their surrounding conduits. Throughput levels may be rapidly changed--up and down--without sacrificing stable operation. A control system is presented for varying the flow rates of the oxidant and fuel streams and/or for switching the reactant streams through one or both sections of the subject burner, thereby effecting a rapid turndown of the burner and in the production of the effluent gas.

Partial oxidation high turndown apparatus

A partial oxidation process and control system for continuously producing synthesis gas, fuel gas or reducing gas in which one process fuel is replaced by a different fuel without shutting down or depressurizing the gas generator. This multifuel process is not tied to one particular fuel and reacts slurries of solid carbonaceous fuel and/or liquid or gaseous hydrocarbonaceous fuels. Suitable burners for introducing the feedstreams into the gas generator comprise a central conduit means radially spaced from a concentric coaxial outer conduit having a downstream exit nozzle, and providing a coaxial annular passage means therebetween. The central conduit means may be retracted upstream from the burner face a distance of about 0 to 12 and preferably 3 to 10 times the minimum diameter of the central exit orifice. A premix zone is preferably provided comprising one or more, say 2 to 5 coaxial chambers in series where substantial mixing of the reactant streams and optionally volatilization of the slurry medium takes place. A control system is provided for switching the type of reactant fuel stream flowing through either the central conduit means or the annular passage means of the burner and adjusting the flow rates of the reactant stream of free-oxygen containing gas.

Partial oxidation process

An integrated process for the production of fuels from tar sands in which bitumen is recovered from the tar sand by a hot-water separation step, recovered bitumen is converted in a hydroconversion step to gaseous and liquid fuels, carbonaceous residue from the bitumen conversion step is gasified with oxygen to produce synthesis gas, hot synthesis gas from the gasification step is water washed, hot water from the water wash step provides hot water for the separation step, and synthesis gas from the gasification step provides hydrogen for the bitumen conversion step. Soot recovered from the synthesis gas in the water wash step is transferred to the bitumen in the separation step and ultimately consumed in the process. Water contaminants from the tar sand separation step are largely eliminated in the gasification step.

Process for the production of fuels from tar sands

A partial oxidation process for continuously producing synthesis gas, fuel gas or reducing gas in which process one fuel is replaced by a differing fuel without shutting down or depressurizing the gas generator. This multifuel process is not tied to one particular fuel and reacts slurries of solid carbonaceous fuel and/or liquid or gaseous hydrocarbonaceous fuels. Problems of fuel availability are reduced due to the wide selection of fuels that are suitable for the subject process. A two-section burner having a high turndown feature is employed that comprises a central conduit; a central bunch of tubes positioned in said central conduit; an outer conduit coaxial with said central conduit and forming an annular passage therewith; and an annular bunch of tubes positioned in said annular passage. The downstream ends of said central and/or annular bunches of tubes are respectively retracted upstream from the burner face a distance of about 0 to 12 i.e. 3 to 10 times the minimum diameter of the central exit orifie and the minimum width of the annular exit orifice. A control system is provided for switching the type of reactant fuel streams flowing through either one or both sections of the burner. The flow rates of the oxidant, fuel, and temperature moderator streams may also be varied in either one or both sections of the burner, thereby effecting a rapid turndown or turnup of the burner and a change in the production of the effluent gas.

High turndown partial oxidation process

A process for the partial oxidation of pumpable slurries of solid carbonaceous fuels in which the pumpable slurry of solid carbonaceous fuel in a liquid carrier is passed in liquid phase through one passage of a burner comprising a retracted central coaxial conduit, an outer coaxial conduit with a converging orifice at the downstream tip of the burner and, optionally, an intermediate coaxial conduit. The downstream tips of the central conduit and the intermediate conduit, if any, are retracted upstream from the burner face a distance of respectively two or more say 3 to 10 for the central conduit, and about 0 to 12 say 1 to 5 for the intermediate conduit times the minimum diameter of the converging orifice of the outer conduit at the burner tip. A pre-mix zone is thereby provided comprising one or more, say 2 to 5 coaxial pre-mix chambers in series. The free-oxygen containing stream is passed through a separate passage of the burner into the pre-mix zone, in which mixing takes place with the slurry of solid carbonaceous fuel and liquid carrier. From 0 to 100, say about 2 to 80, volume % of the liquid carrier may be vaporized in the pre-mix zone. The multiphase mixture of reactants is then discharged into the reaction zone of the free-flow partial oxidation gas generator by way of the converging orifice of the outer conduit at the burner tip. Synthesis gas, fuel gas, or reducing gas is thereby produced.

Process for the partial oxidation of slurries of solid carbonaceous fuel

An apparatus in which a downflowing high pressure stream of hot raw synthesis gas from the reaction zone of a free flow partial oxidation gas generator at a temperature in the range of about 1800.degree. to 3000.degree. F. is passed through a first gas diversion and residue separation chamber contained in a first pressure vessel where the velocity of the gas stream is reduced, solid material and molten slag are separated by gravity from the gas stream, and the direction is diverted into a thermally insulated side transfer line. The hot gas stream is then passed through a thermally insulated gas-solids impingement separation means contained in a second pressure vessel where its direction and velocity is changed and additional residue is separated. The hot gas stream is then passed upwardly through a radiant cooler where additional solid matter is removed by gravity and the gas temperature is reduced to a temperature in the range of about 900.degree. to 1800.degree. F. By the subject apparatus, combustion residue may be removed from the raw stream of synthesis gas, and its sensible heat may be extracted at maximum temperature to produce by-product steam.

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Tarrytown, NY, United States of America

Edward T Child