초록 ▼

A process for gasification of cellulosic biomass in a single gasification vessel wherein the cellulosic biomass is introduced directly into a single back-mixed fluidized bed of high heat capacity inert solids. The fluidized bed is maintained at temperatures of about 1200°to about 1600°F., pressures

A process for gasification of cellulosic biomass in a single gasification vessel wherein the cellulosic biomass is introduced directly into a single back-mixed fluidized bed of high heat capacity inert solids. The fluidized bed is maintained at temperatures of about 1200°to about 1600°F., pressures of up to about 500 psig devolatilizing the biomass. A substantial portion of the heavier hydrocarbons produced by devolatilization of the biomass is reformed within the gasification vessel and a substantial portion of the devolatilized biomass is gasified by reaction with hydrogen and steam within the fluidized bed. Biomass residue is combusted in an oxygen-rich atmosphere in the lower portion of the fluidized bed to principally form heat and biomass ash. The highly back-mixed fluidized bed results in temperature variation along the height of the bed, including the combustion zone, of less than 100°F. Introduction of cellulosic biomass feed to the fluidized bed is vertically adjustable and maintained at a position where the combustion consumes principally biomass residue. Formed gases, vapor and biomass ash are removed from the top of the gasification vessel in the gas stream. The process provides high throughput, efficient production of low and medium Btu fuel gas. The medium Btu fuel gas may be readily upgraded to high Btu SNG. At least half of the methane required for SNG is produced in the gasification vessel.

대표청구항 ▼

A process for gasification of cellulosic biomass in a single gasification and combustion vessel comprising the steps: introducing cellulosic biomass of up to about 50 weight percent moisture directly into a single, highly back-mixed fluidized bed of high heat capacity inert solids in said vessel; ma

A process for gasification of cellulosic biomass in a single gasification and combustion vessel comprising the steps: introducing cellulosic biomass of up to about 50 weight percent moisture directly into a single, highly back-mixed fluidized bed of high heat capacity inert solids in said vessel; maintaining said fluidized bed at temperatures of about 1200°to about 1600°F., said highly back-mixed fluidized state maintaining the temperature variation throughout the height of said fluidized bed at less than about 75°F., at a pressure of up to about 500 psig, devolatilizing said biomass in hydrogen-rich atmosphere in an upper portion of said bed forming methane, heavier hydrocarbons, carbon oxides, steam, hydrogen and devolatilized biomass; reforming a substantial portion of said heavy hydrocarbons into methane, carbon oxides and steam within said fluidized bed and in the head space of said vessel; mixing said devolatilized biomass throughout said fluidized bed and gasifying a substantial portion of said devolatilized biomass by reaction with hydrogen and steam within said upper portion of said bed producing methane, carbon oxides, hydrogen and biomass residue; combusting said biomass residue in an oxygen-rich atmosphere in a combustion zone in a lower portion of said bed to principally form heat and biomass ash, said heat being directly transferred to said inert solids in said single fluidized bed to maintain said fluidized bed temperatures; introducing and distributing oxygen containing gas to said bed below said combustion zone to maintain said oxygen-rich atmosphere, said oxygen introduced in an amount which is substantially less than stoichiometrically required for combustion of said biomass residue, so that said oxygen containing gas is substantially consumed in said combustion zone; removing formed gases, vapor and substantially all of said biomass ash in a gas stream from the top of said gasification vessel; and maintaining said introduction of cellulosic biomass to said bed at a point where said combustion consumes principally biomass residue.