Method for the gasification of carbonaceous matter by plasma arc pyrolysis

Claim 1

A method for producing fuel gases from particulate carbonaceous matter comprising the steps of: (a) providing a refractory-lined furnace vessel characterized by the presence of a hearth member containing an electrically conductive refractory material, an unobstructed chamber area positioned immediately above and encompassing said hearth member, substantially air-tight means for continuously introducing said carbonaceous matter at a controlled rate into said furnace from an elevated position therein, means for admitting a carbon combining reactant into said furnace, means for removing product gases and ash residue from said furnace, said wherein said furnace is further characterized by the presence of one or more electrically powered and gas supplied long arc plasma torches mounted in the walls thereof with the respective arc sustaining ends of each of said torches being directed toward said hearth; (b) striking an initial plasma arc between each of said plasma torches and said electrically conductive material contained in said hearth member and thereafter supplying sufficient power to said torches to bring the interior chamber area of said furnace vessel to a substantially uniform and stable, preselected temperature of at least 800° C., with said uniformity of temperature being achieved by the radiation of heat from the internal surfaces of said furnace vessel; (c) continuously introducing a charge of particulate carbonaceous matter into said furnace from an elevated position therein and in a manner such as to substantially preclude atmospheric air from entering the interior of said furnace, the rate of said introduction being correlated with and dependent upon said furnace chamber temperature, said particulate carbonaceous matter charge being characterized by a substantially uniform fixed carbon content and having a particle size of less than about 3/4 inch; (d) permitting said carbonaceous matter to fall by gravity over a predetermined distance from said elevated position to the surface of said electrically conductive material contained in said hearth member, wherein during the course of said fall the carbonaceous matter is devolatilized and the volatiles so obtained are thermally cracked to produce short chain hydrocarbons; (e) allowing the devolatilized carbonaceous matter to continuously deposit as char on the surface of said conductive material in a single level, non-tiered array at a selected number of gasification sites, the quantity and configuration of said char deposits being controlled such that the unoccupied volume and free surface area of said furnace are maintained in substantial excess over that of the combined volume and surface area of said deposits; (f) simultaneously with the introduction of said carbonaceous matter introducing substantially stoichiometric quantities of a carbon combining reactant into said furnace vessel for reaction with the fixed carbon of said char deposits to produce fuel gases therefrom, wherein said carbon combining reactant is selected from the group consisting of hydrogen, ammonia and water, with said water being introduced in the form of steam or as a liquid; (g) monitoring the interior temperature of said furnace vessel and varying the power supplied to said plasma torches during temperature fluctuations therein to maintain the temperature at said preselected level; (h) continuously withdrawing the gaseous products produced in said furnace; and (i) removing accumulated residual ash from the hearth of said furnace in a continuous manner or at selected intervals.

Claim 2

A method for producing fuel gases from particulate carbonaceous matter comprising the steps of: (a) providing a refractory-lined furnace vessel characterized by the presence of a hearth member containing an electrically conductive refractory material, an unobstructed chamber area positioned immediately above and encompassing said hearth member, substantially air-tight means for continuously introducing said carbonaceous matter at a controlled rate into said furnace from an elevated position therein, means for admitting a carbon combining reactant into said furnace, means for removing product gases and ash residue from said furnace, said wherein said furnace is further characterized by the presence of one or more electrically powered and gas supplied long arc plasma torches mounted in the walls thereof with the respective arc sustaining ends of each of said torches being directed toward said hearth; (b) striking an initial plasma arc between each of said plasma torches and said electrically conductive material contained in said hearth member and thereafter supplying sufficient power to said torches to bring the interior chamber area of said furnace vessel to a substantially uniform and stable, preselected temperature of at least 800° C., with said uniformity of temperature being achieved by the radiation of heat from the internal surfaces of said furnace vessel; (c) continuously introducing a charge of particulate carbonaceous matter into said furnace from an elevated position therein and in a manner such as to substantially preclude atmospheric air from entering the interior of said furnace, the rate of said introduction being correlated with and dependent upon said furnace chamber temperature, said particulate carbonaceous matter charge being characterized by a substantially uniform fixed carbon content and having a particle size of less than about 3/4 inch; (d) permitting said carbonaceous matter to fall by gravity over a predetermined distance from said elevated position to the surface of said electrically conductive material contained in said hearth member, wherein during the course of said fall the carbonaceous matter is devolatilized and the volatiles so obtained are thermally cracked to produce short chain hydrocarbons; (e) allowing the devolatilized carbonaceous matter to continuously deposit as char on the surface of said conductive material in a single level, non-tiered array at a selected number of gasification sites, the quantity and configuration of said char deposits being controlled such that the unoccupied volume and free surface area of said furnace are maintained in substantial excess over that of the combined volume and surface area of said deposits; (f) simultaneously with the introduction of said carbonaceous matter introducing substantially stoichiometric quantities of a carbon combining reactant into said furnace vessel for reaction with the fixed carbon of said char deposits to produce fuel gases therefrom, wherein said carbon combining reactant is selected from the group consisting of hydrogen, ammonia and water, with said water being introduced in the form of steam or as a liquid; (g) monitoring the interior temperature of said furnace vessel and varying the power supplied to said plasma torches during temperature fluctuations therein to maintain the temperature at said preselected level; (h) continuously withdrawing the gaseous products produced in said furnace; and (i) removing accumulated residual ash from the hearth of said furnace in a continuous manner or at selected intervals.

Claim 15

A method for producing fuel gases from particulate carbonaceous matter comprising the steps of: (a) providing a refractory-lined furnace vessel characterized by the presence of a hearth member, an unobstructed chamber area positioned immediately above and encompassing said hearth member, substantially air-tight means for continuously introducing said carbonaceous matter at a controlled rate into said furnace from an elevated position therein, means for admitting a carbon combining reactant into said furnace, means for removing the product gases and ash residue from said furnace, and wherein said furnace is further characterized by the presence of one or more electrically powered and gas supplied long arc plasma torches mounted in the walls thereof with the respective arc sustaining ends of each of said torches being directed toward said hearth; (b) placing a selected volume of an electrically conductive and meltable metal composition which contains slagging components into said hearth member; (c) striking an initial plasma arc between each of said plasma torches and said electrically conductive and meltable metal composition and thereafter supplying sufficient power to said torches to form an electrically conductive molten metal bath having a molten slag-containing surface layer within said hearth member and to bring the internal chamber area of said furnace vessel to a substantially uniform and stable preselected temperature of at least 800° C., with said uniformity of temperature being achieved by the radiation of heat from the internal surfaces of said furnace vessel; (d) continuously introducing a charge of particulate carbonaceous matter into said furnace from an elevated position therein and in a manner such as to substantially preclude atmospheric air from entering the interior of said furnace, the rate of said introduction being correlated with and dependent upon said furnace chamber temperature, said particulate carbonaceous matter charge being characterized by a substantially uniform fixed carbon content and having a particle size of less than about 3/4 inch; (e) permitting said carbonaceous matter to fall by gravity over a predetermined distance from said elevated position to said surface layer of said electrically conductive molten bath to effect a devolatilization of said carbonaceous matter together with a subsequent cracking of the resulting volatiles during the course of said fall; (f) allowing the devolatilized carbonaceous matter to continuously deposit as a char and float on the slag surface layer of said melt in a single level, non-tiered array at a selected number of gasification sites, the quantity and configuration of said char deposits being controlled such that the unoccupied volume and free surface area of said furnace are maintained in substantial excess over that of the combined volume and surface area of said deposits; (g) simultaneously with the introduction of said carbonaceous matter introducing substantially stoichiometric quantities of a carbon combining reactant into said furnace vessel for reaction with the fixed carbon of said char deposits to produce fuel gases therefrom, wherein said carbon combining reactant is selected from the group consisting of hydrogen, ammonia and water, with said water being introduced as steam or in the liquid state; (h) monitoring the interior temperature of said furnace vessel and varying the power supplied to said plasma torches during temperature fluctuations therein to maintain the temperature at said preselected level; (i) continuously withdrawing the gaseous products produced in said furnace; and (j) removing accumulated residual ash from the hearth of said furnace continuously or at selected intervals.

Claim 16

A method for producing fuel gases from particulate carbonaceous matter comprising the steps of: (a) providing a refractory-lined furnace vessel characterized by the presence of a hearth member, an unobstructed chamber area positioned immediately above and encompassing said hearth member, substantially air-tight means for continuously introducing said carbonaceous matter at a controlled rate into said furnace from an elevated position therein, means for admitting a carbon combining reactant into said furnace, means for removing the product gases and ash residue from said furnace, and wherein said furnace is further characterized by the presence of one or more electrically powered and gas supplied long arc plasma torches mounted in the walls thereof with the respective arc sustaining ends of each of said torches being directed toward said hearth; (b) placing a selected volume of an electrically conductive and meltable metal composition which contains slagging components into said hearth member; (c) striking an initial plasma arc between each of said plasma torches and said electrically conductive and meltable metal composition and thereafter supplying sufficient power to said torches to form an electrically conductive molten metal bath having a molten slag-containing surface layer within said hearth member and to bring the internal chamber area of said furnace vessel to a substantially uniform and stable preselected temperature of at least 800° C., with said uniformity of temperature being achieved by the radiation of heat from the internal surfaces of said furnace vessel; (d) continuously introducing a charge of particulate carbonaceous matter into said furnace from an elevated position therein and in a manner such as to substantially preclude atmospheric air from entering the interior of said furnace, the rate of said introduction being correlated with and dependent upon said furnace chamber temperature, said particulate carbonaceous matter charge being characterized by a substantially uniform fixed carbon content and having a particle size of less than about 3/4 inch; (e) permitting said carbonaceous matter to fall by gravity over a predetermined distance from said elevated position to said surface layer of said electrically conductive molten bath to effect a devolatilization of said carbonaceous matter together with a subsequent cracking of the resulting volatiles during the course of said fall; (f) allowing the devolatilized carbonaceous matter to continuously deposit as a char and float on the slag surface layer of said melt in a single level, non-tiered array at a selected number of gasification sites, the quantity and configuration of said char deposits being controlled such that the unoccupied volume and free surface area of said furnace are maintained in substantial excess over that of the combined volume and surface area of said deposits; (g) simultaneously with the introduction of said carbonaceous matter introducing substantially stoichiometric quantities of a carbon combining reactant into said furnace vessel for reaction with the fixed carbon of said char deposits to produce fuel gases therefrom, wherein said carbon combining reactant is selected from the group consisting of hydrogen, ammonia and water, with said water being introduced as steam or in the liquid state; (h) monitoring the interior temperature of said furnace vessel and varying the power supplied to said plasma torches during temperature fluctuations therein to maintain the temperature at said preselected level; (i) continuously withdrawing the gaseous products produced in said furnace; and (j) removing accumulated residual ash from the hearth of said furnace continuously or at selected intervals.