Abstract:
Synthesis gas, fuel gas, or reducing gas is produced by the noncatalytic partial oxidation of a slurry of ash-containing solid carbonaceous fuel in a liquid carrier with a free-oxygen containing gas in the free-flow reaction zone of a refractory lined gas generator at an autogenous temperature in the range of about 2350.degree. F. to 2900.degree. F. so that about 75 to 95 weight percent of the carbon in the fuel feed to the reaction zone is converted into carbon oxides. The hot effluent gas stream from the reaction zone containing entrained particulate carbon, unconverted solid carbonaceous fuel, and molten slag is passed through a free-flow radiant cooler where it is contacted by and provides the heat to vaporize an aqueous solution of catalyst consisting of alkali metal and/or alkaline earth metal compound in water. In the presence of the catalyst, H.sub.2 O and at least a portion of the particulate carbon and the carbon in the unconverted solid carbonaceous fuel are reacted together at a controlled temperature to produce additional H.sub.2 and CO.sub.x. The hot effluent gas stream enters the radiant cooler at a temperature in the range of about 2800.degree. F.-2300.degree. F. and leaves at a temperature in the range of about 1350.degree. F.-1600.degree. F. Further, the molten slag in the effluent gas stream may be fluxed with the alkali metal and/or alkaline earth metal compound to facilitate separation of the slag from the effluent gas stream.
Abstract:
A method of particulate-carbon recovery from the product gas in a coal gasification process of the type using water-carbon slurry combusted with oxygen in a reactor uses water scrubbing for the product gas to obtain particulate carbon together with ash. Certain ash content is trapped in carbon particles which have a tendency of lumping together. The carbon and ash fraction is treated with liquid hydrocarbon for carbon particle wetting and facilitating separation of ash. The recovered carbon is ground to break down bigger carbon particles and sent through a wet-particle separator; carbon particles which pass a predetermined mesh size, e.g., approximately 63 micron mesh, are sent back to the reactor for mixing with the water-carbon slurry inlet for further combustion. The bigger fractions of carbon are either ground down to size again, or diverted for other uses. Recycling carbon particles which pass a 63 micron mesh and are almost devoid of ash improves the carbon utilization and significantly reduces total ash formed. The abrasion damage on components because of ash is also reduced.
Abstract:
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.
Abstract:
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.
Abstract:
A burner and 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.
Abstract:
Carbonaceous solids slurried in an aqueous solution, which preferably contains catalyst constituents having gasification activity, are dried by contacting the slurry with superheated steam in a fluid bed slurry dryer and the resultant dried solids are subsequently gasified with steam generated in the dryer.
Abstract:
Low quality solid fuels are gasified by being fed to a gasifier in a concentrated water slurry, the high solids content of the slurry being possible by subjecting the solid fuel to hydrothermal treatment in the product gas quench zone.