Process for gasification of cellulosic materials

Claim 2

A process for gasification of cellulosic materials in a single gasification and combustion vessel comprising the steps: introducing cellulosic materials feed 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 90° F., at a pressure of up to about 500 psig, devolatilizing said cellulosic materials in hydrogen-rich atmosphere in an upper portion of said bed forming methane, heavier hydrocarbons, carbon oxides, steam, hydrogen and devolatilized cellulosic materials; 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 cellulosic materials throughout said fluidized bed and gasifying a substantial portion of said devolatilized cellulosic materials by reaction with hydrogen and steam within said upper portion of said bed producing methane, carbon oxides, hydrogen and cellulosic materials residue; combusting said cellulosic materials residue in an oxygen-rich atmosphere in a combustion zone in a lower portion of said bed to principally form heat and cellulosic materials 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 cellulosic materials residue, so that said oxygen containing gas is substantially consumed in said combustion zone; removing formed gases, vapor and substantially all of said cellulosic materials ash in a gas stream from the top of said gasification vessel; and maintaining said introduction of cellulosic materials to said bed at a point where said combustion consumes principally cellulosic materials residue.

Claim 3

The process of claim 1 wherein said cellulosic materials feed is selected from the group consisting of biomass, municipal solid wastes, industrial solid wastes, and mixtures thereof.

Claim 4

The process of claim 1 wherein said cellulosic materials feed is principally cellulosic biomass.

Claim 5

The process of claim 1 wherein said cellulosic materials feed is principally municipal solid waste.

Claim 6

The process of claim 1 wherein said cellulosic materials feed is principally refuse derived fuel.

Claim 7

The process of claim 1 wherein said pressure is maintained at about 200 to about 500 psig.

Claim 8

The process of claim 1 wherein said cellulosic material introduced to said fluidized bed has about 5 to about 50 weight percent moisture.

Claim 9

The process of claim 1 wherein said fluidized bed is maintained at temperatures of about 1500° to 1600° F. and the residence time of said cellulosic materials in said vessel is about 1/2 to about 8 minutes.

Claim 10

The process of claim 8 wherein said pressure is about 300 to about 500 psig.

Claim 11

The process of claim 1 wherein all heat necessary to provide said temperatures is provided by combustion in said combustion zone.

Claim 12

The process of claim 1 wherein steam is additionally introduced and distributed to said fluidized bed.

Claim 13

The process of claim 11 wherein said cellulosic materials introduced into said reactor has a moisture content of about 5 to about 25 weight percent.

Claim 14

The process of claim 1 wherein said cellulosic materials introduced into said reactor has a moisture content of about 40 to about 50 weight percent and provides all steam for said gasification.

Claim 15

The process of claim 1 wherein said cellulosic materials feed comprises plant material selected from the group consisting of terrestial, aquatic and mixtures thereof.

Claim 16

The process of claim 1 wherein said cellulosic materials feed comprises particles having their greatest dimension less than about 1/4 to about 11/2 inches.

Claim 17

The process of claim 1 wherein said cellulosic materials feed is introduced into said fluidized bed by pneumatic transport provided by gas selected from the group consisting of steam, recycled product gas, carbon dioxide recovered from product gas, and mixtures thereof.

Claim 18

The process of claim 1 wherein said inert solids are selected from the group consisting of silica, alumina, mullite, and mixtures thereof and have mean particle diameters of about 0.06 to about 0.70 millimeters.

Claim 19

The process of claim 1 wherein the residence time of said cellulosic materials withing said vessel is about 4 to about 8 minutes.

Claim 20

The process of claim 1 wherein said cellulosic material feed is principally selected from the group consisting of municipal solid waste and refuse derived fuel.

Claim 21

The process of claim 1 wherein said temperature variation throughout the height of said fluidized bed is maintained at less than about 50° F.

Claim 22

The process of claim 20 wherein said cellulosic materials feed is principally selected from the group consisting of municipal solid waste and refuse derived fuel.

Claim 23

In a process for high methane content gas production, the improvement comprising gasification of cellulosic materials feed in a single gasification and combustion vessel comprising the steps: introducing cellulosic materials feed 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 90° F., at a pressure of up to about 500 psig, and providing a hydrogen-containing gaseous atmosphere in a portion of said bed above a combustion zone for hydrodevolatilizing said cellulosic materials converting it to methane, heavier hydrocarbons, carbon oxides, steam, hydrogen and devolatilized cellulosic materials; 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 cellulosic materials throughout said fluidized bed and gasifying a substantial portion of said devolatilized cellulosic materials by reaction with hydrogen and steam producing methane, carbon oxides, hydrogen and cellulosic materials residue; combusting said cellulosic materials residue in an oxygen-rich atmosphere in a combustion zone in a lower portion of said bed to principally form heat and cellulosic materials ash, said heat being directly transferred to said inert solids in said single bed to maintain said fluidized bed temperatures; introducing and distributing oxygen containing gas to said combustion zone to maintain said oxygen-rich atmosphere, said oxygen introduced in an amount which is sutstantially less than stoichiometrically required for combustion of said cellulosic materials residue, so that said oxygen containing gas is substantially consumed in said combustion zone; removing formed gases, vapor and substantially all of said cellulosic materials ash in a gas stream from the top of said gasification vessel; and maintaining said introduction of cellulosic materials to said bed at a point where said combustion consumes principally cellulosic materials residue.

Claim 24

In a process for high methane content gas production, the improvement comprising gasification of cellulosic materials feed in a single gasification and combustion vessel comprising the steps: introducing cellulosic materials feed 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 90° F., at a pressure of up to about 500 psig, and providing a hydrogen-containing gaseous atmosphere in a portion of said bed above a combustion zone for hydrodevolatilizing said cellulosic materials converting it to methane, heavier hydrocarbons, carbon oxides, steam, hydrogen and devolatilized cellulosic materials; 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 cellulosic materials throughout said fluidized bed and gasifying a substantial portion of said devolatilized cellulosic materials by reaction with hydrogen and steam producing methane, carbon oxides, hydrogen and cellulosic materials residue; combusting said cellulosic materials residue in an oxygen-rich atmosphere in a combustion zone in a lower portion of said bed to principally form heat and cellulosic materials ash, said heat being directly transferred to said inert solids in said single bed to maintain said fluidized bed temperatures; introducing and distributing oxygen containing gas to said combustion zone to maintain said oxygen-rich atmosphere, said oxygen introduced in an amount which is sutstantially less than stoichiometrically required for combustion of said cellulosic materials residue, so that said oxygen containing gas is substantially consumed in said combustion zone; removing formed gases, vapor and substantially all of said cellulosic materials ash in a gas stream from the top of said gasification vessel; and maintaining said introduction of cellulosic materials to said bed at a point where said combustion consumes principally cellulosic materials residue.

Claim 25

The process of claim 22 wherein said pressure is maintained at about 200 to about 500 psig.

Claim 26

The process of claim 22 wherein said cellulosic materials introduced to said fluidized bed has about 5 to about 50 weight percent moisture.

Claim 27

The process of claim 22 wherein said fluidized bed is maintained at temperatures of about 1500° to 1600° F. and the residence time of said cellulosic materials in said vessel is about 1/2 to about 8 minutes.

Claim 28

The process of claim 25 wherein said pressure is about 300 to about 500 psig.

Claim 29

The process of claim 22 wherein all heat necessary to provide said temperatures is provided by combustion in said combustion zone.

Claim 30

The process of claim 22 wherein said cellulosic materials feed introduced into said reactor has a moisture content of about 40 to about 50 weight percent and provides steam for said gasification.

Claim 31

The process of claim 22 wherein said cellulosic materials feed comprises particles having their greatest dimension less than about 1/4 to about 11/2 inches.

Claim 32

The process of claim 22 wherein said cellulosic materials feed is selected from the group consisting of biomass, municipal solid wastes, industrial solid wastes, and mixtures thereof.

Claim 33

The process of claim 22 wherein said cellulosic materials feed is princiaplly cellulosic biomass.

Claim 34

The process of claim 22 wherein said cellulosic materials feed is principally municipal solid waste.

Claim 35

The process of claim 22 wherein said cellulosic materials feed is principally refuse derived fuel.

Claim 36

The process of claim 22 wherein said cellulosic materials feed is principally selected from the group consisting of municipal solid waste and refuse derived fuel.

Claim 37

In a process for methanol production, the improvement comprising gasification of cellulosic materials in a single gasification and combustion vessel comprising the steps: introducing cellulosic materials feed 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 90° F., a pressure of up to about 500 psig, devolatilizing said cellulosic materials in a portion of said bed above a combustion zone forming methane, heavier hydrocarbons, carbon oxides, steam, hydrogen and devolatilized cellulosic materials; 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 cellulosic materials throughout said fluidized bed and gasifying a substantial portion of said devolatilized cellulosic materials by reaction with hydrogen and steam within said portion of said bed above said combustion zone producing methane, carbon oxides, hydrogen and cellulosic materials residue; combusting said cellulosic materials residue in an oxygen-rich atmosphere in a combustion zone in a lower portion of said bed to principally form heat and cellulosic materials ash, said heat being directly transferred to said inert solids in said single bed to maintain said fluidized bed temperatures; introducing and distributing oxygen containing gas to 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 cellulosic materials residue, so that said oxygen containing gas is substantially consumed in said combustion zone; removing formed gases, vapor and substantially all of said cellulosic materials ash in a gas stream from the top of said gasification vessel; and maintaining said introduction of cellulosic materials to said bed at a point where said combustion consumes principally cellulosic materials residue; and reforming said formed gases to CO and H 2 and catalytically reacting said CO and H 2 to produce said methanol.

Claim 38

In a process for methanol production, the improvement comprising gasification of cellulosic materials in a single gasification and combustion vessel comprising the steps: introducing cellulosic materials feed 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 90° F., a pressure of up to about 500 psig, devolatilizing said cellulosic materials in a portion of said bed above a combustion zone forming methane, heavier hydrocarbons, carbon oxides, steam, hydrogen and devolatilized cellulosic materials; 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 cellulosic materials throughout said fluidized bed and gasifying a substantial portion of said devolatilized cellulosic materials by reaction with hydrogen and steam within said portion of said bed above said combustion zone producing methane, carbon oxides, hydrogen and cellulosic materials residue; combusting said cellulosic materials residue in an oxygen-rich atmosphere in a combustion zone in a lower portion of said bed to principally form heat and cellulosic materials ash, said heat being directly transferred to said inert solids in said single bed to maintain said fluidized bed temperatures; introducing and distributing oxygen containing gas to 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 cellulosic materials residue, so that said oxygen containing gas is substantially consumed in said combustion zone; removing formed gases, vapor and substantially all of said cellulosic materials ash in a gas stream from the top of said gasification vessel; and maintaining said introduction of cellulosic materials to said bed at a point where said combustion consumes principally cellulosic materials residue; and reforming said formed gases to CO and H 2 and catalytically reacting said CO and H 2 to produce said methanol.