Abstract:
A method is provided for turning down or up the output of raw product gas from a partial oxidation gas generator while maintaining in an acceptable range the efficiency of the gas generation, or conversion of the fuel to gas, and the quality of the gas produced. In the process, the flow rates for the separate feedstreams to the burner comprising fuel optionally in admixture with a temperature moderator, at least one stream of free-oxygen containing gas optionally in admixture with a temperature moderator, and with or without a separate feedstream of temperature moderator are adjusted down or up a predetermined amount to obtain a specified output of raw product gas while maintaining substantially constant in the reaction zone the levels of O/C atomic ratio and the temperature moderator/fuel weight ratio. Further, the temperature of at least one stream of free-oxygen containing gas optionally in admixture with a temperature moderator is increased at turn-down and decreased at turn-up to a predetermined value which is an indirect function of its adjusted flow rate. By this means, the burner tip velocity of the temperature adjusted stream of free-oxygen containing gas optionally in admixture with a temperature moderator is held within an acceptable range, and changes in the process efficiency and pressure drop across the burner are minimized.
Abstract:
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.
Abstract:
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.
Abstract:
A method of hydrogenation of unsaturated hydrocarbons for syngas production is presented. A hydrogenation feed reactor stream is introduced into a hydrogenation reactor, thereby producing a reformer feed stream. The reformer feed stream is introduced into a reformer, thereby producing a crude syngas stream. The crude syngas stream is introduced into a water gas shift converter, thereby producing a hydrogen-rich stream. The hydrogen-rich stream is separated in a separation means, thereby producing a carbon dioxide-rich stream and a hydrogen product stream. At least a portion of the hydrogen product stream is combined with a refinery fuel gas stream, and a natural gas stream, to form the hydrogenation reactor feed stream.
Abstract:
An improved gasification system, in which synthesis gas is produced through the operation of a fuel gas production bed comprising an upper layer (66) of organic input material, typically in the form of pellets or briquettes of substantially uniform size and configuration, two intermediate layers, one intermediate layer (70) for carbonizing the input material, and the other intermediate layer (72) for partially oxidizing and substantially completely pyrolyzing the input material and a lower layer (68) of tar-free charcoal. The length of the gas production bed from the top of the upper intermediate layer to the point where gas exits from the gas production bed is approximately at least 1.5 times the diameter of the bed, but not less than 7 feet. The removal of charcoal from the gas production bed is controlled and the operation of the bed otherwise controlled such that the charcoal produced during the process is activated carbon. A multi-stage gas cooling system is provided to bring the gas quickly and efficiently to a relatively low temperature for end use.
Abstract:
An improved gas generator in which the composition of gas generated in a heated reactor is maintained when the flow rate from the reactor is adjusted. To accomplish this, the generator includes two diverting means responsive to the flow rate. The first diverts a portion of the reactant mixture before it enters the reactor, the diverted amount being insufficient to change the composition of the generated gas. The second diverts a portion of the generated gas to a burner for heating the reactor.
Abstract:
Control process for producing an aqueous slurry of solid carbonaceous fuel having a desired solids concentration for feed to a partial oxidation gas generator by grinding together in a size reduction zone a recycle aqueous slurry stream comprising carbon-containing particulate solids, a stream of solid carbonaceous fuel, and a specific amount of make-up water. No valves are in the line or path between the size reduction zone and the feed tanks for the solid carbonaceous fuel and recycle aqueous slurry. A system control unit automatically calculates the amount of make-up water and provides a corresponding signal to control the flow rate. Input signals that are provided to the system control unit include those corresponding to the weigh belt feeder speed and moisture content for the solid carbonaceous fuel; and pump speed, weight fraction, temperature, and density of the solids for the slurry of recycle particulate solids.
Abstract:
In a method for safely operating a coal gasifier which is indirectly cooled by passing a heat-carrying oil through a cooling jacket of the gasifier, the pressure of the heat-carrying oil is continually measured after having passed through the cooling jacket. If the measured pressure falls below a predetermined pressure, the supply of coal and gasifying agents to the gasifier is interrupted, the passage of heat-carrying oil is interrupted and water or steam is passed through the cooling jacket until the gasifier is safely shutdown.
Abstract:
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.
Abstract:
Fuel and oxidant feed rates into a gasifier 202 are regulated by monitoring overall output 14 and comparing with a pre-selected setpoint valve 10. An overall load demand signal 50, responsive to this comparision is generated and used as an input to control 102 oxidant feed rate. The heating value of the product gas is measured 76 and used to control 64 overall fuel feed rate to the gasifier 202. For a two stage slagging gasifier, the present invention controls 114 fuel feed rate to the slagging stage 210 responsive to the measured slagging stage reaction temperature 128.