Process for gasifying granulated carbonaceous fuel

Claim 2

A PROCESS FOR GASIFYING A GRANULATED CARBONACEOUS FUEL, COMPRISING: A. SUPPLYING A GRANULATED CARBONACEOUS FUEL TO A VESSEL HOUSING CONTIGUOUS UPPER AND LOWER FLUIDIZED BED ZONES WHICH ARE AT A TEMPERATURE BETWEEN ABOUT 1,900* AND 2,100*F. SAID UPPER ZONE COMPRISING A FAST FLUIDIZED BED OF FINE PARTICLES AND SAID LOWER ZONE COMPRISING A SLOW FLUIDIZED BED OF LARGE PARTICLES, B. SUPPLYING A GASIFICATION MEDIUM AS FLUIDIZING GAS TO SAID LOWER ZONE, SAID GASIFICATION MEDIUM BEING SELECTED FROM THE GROUP OF GAS MIXTURES COMPRISING OXYGEN AND STEAM, AIR AND STEAM, AIR AND COMBUSTION PRODUCTS CONTAINING CARBON DIOXIDE, AND AIR, C. WITHDRAWING PRODUCTS OF THE GASIFICATION OF SAID FUEL TOGETHER WITH SAID FINE PARTICLES FROM SUBSTANTIALLY THE TO OF SAID UPPER ZONE, SEPARATING SAID PRODUCTS OF GASIFICATION FROM SAID FINE PARTICLES IN A CYCLONE SEPARATOR, DISCHARGING SAID SEPARATED PRODUCTS OF GASIFICATION, CAUSING SAID SEPARATED FINE PARTIFLES TO FLOW FROM SAID CYCLONE SEPARATOR INTO A STANPIPE, SAID STANDPIPE CONDUCTING SAID FINE PARTICLES INTO A REGION WHICH SAID FINE PARTICLES ARE MAINTAINED IN A SLOW FLUIDIZED STATE, AND CAUSING SAID FINE, PARTICLES TO FLOW FROM SAID REGION INTO SUBSTANTIALLY THE BOTTOM OF SAID UPPER ZONE AT A RATE SUFFICIENT TO MAINTAIN A FAST FLUIDIZED STATE IN SAID UPPER ZONE, AND D. BRINGING SAID FINE PARTICLES INTERMITTENTLY INTO CONTACT WITH A GAS RICH IN STEAM OR CARBON DIOXIDE AND CONTAINING SUBSTANTIALLY NO HYDROGEN OR CARBON MONOXIDE.

Claim 3

The process of claim 1 in which step (d) is accomplished by supplying said gas as fluidizing-gas to said region maintained in a slow fluidized state.

Claim 4

The process of claim 2 in which said fluidizing gAs to said region is selected from the group consisting of steam and carbon dioxide; and including the step of discharging gas from said region separately from said products of gasification discharged in step (c).

Claim 5

The process of claim 1 in which said granulated carbonaceous fuel is selected from the group consisting of anthracites, subanthracites, bituminous coals, subbituminous coals, lignites, and cokes prepared from anthracites, subanthracites, bituminous coals, subbituminous coals, and lignites; in which said lower zone is fluidized at a superficial fluidizing-gas velocity greater than about 4 feet per second; in which said large particles include roughly spherical particles of agglomerated ash matter; and including the step of withdrawing agglomerated ash matter from the bottom of said lower zone.

Claim 6

The process of claim 4 in which said granulated carbonaceous fuel is selected from the group consisting of caking bituminous coals, and in which said fuel is supplied to said vessel at an elevation intermediate between said top and said bottom of said upper zone.

Claim 7

The process of claim 1 in which said fluidized bed zones are at a pressure greater than 10 atmospheres.

Claim 8

A process for gasifying a granulated carbonaceous fuel, comprising: a. supplying a granulated carbonaceous fuel selected from the group consisting of anthracites, subanthracites, bituminous coals, subbituminous coals, lignites, and cokes prepared from anthracites, subanthracites, bituminous coals, subbituminous coals, and lignites to a vessel housing contiguous upper and lower fluidized bed zones which are at a temperature between about 1,900* and 2,100*F, said upper zone comprising a fast fluidized bed of fine particles and said lower zone comprising a slow fluidized bed of large particles, said lower zone being fluidized at a superficial fluidizing-gas velocity greater than about 4 feet per second, said large particles including roughly spherical particles of agglomerated ash matter, b. supplying a gasification medium as fluidizing-gas to said lower zone, said gasification medium being selected from the group of gas mixtures comprising oxygen and steam, air and steam, air and combustion products containing carbon dioxide, and air, c. withdrawing products of the gasification of said fuel together with said fine particles from substantially the top of said upper zone, separating said products of gasification from said fine particles in a cyclone separator, discharging said separated products of gasification, causing said separated fine particles to flow from said cyclone separator into a standpipe, said standpipe conducting said fine particles into a region in which said fine particles are maintained in a slow fluidized state, and causing said fine particles to flow from said region into substantially the bottom of said upper zone at a rate sufficient to maintain a fast fluidized state in said upper zone, d. supplying a gas rich in steam or carbon dioxide and containing substantially no hydrogen or carbon monoxide as fluidizing-gas to said region maintained in a slow fluidized state, and bringing said fine particles intermittently into contact with said gas, and e. withdrawing agglomerated ash matter from the bottom of said lower zone.

Claim 9

A process for gasifying a granulated carbonaceous fuel, comprising: a. supplying a granulated carbonaceous fuel selected from the group consisting of anthracites, subanthracites, bituminous coals, subbituminous coals, lignites, and cokes prepared from anthracites, subanthracites, bituminous coals, subbituminous coals, and lignites to a vessel housing contiguous upper and lower fluidized bed zones which are at a temperature between about 1,900* and 2,100*F, said upper zone comprising a fast fluidized bed of fine particles and said lower zone comprising a slow fluidized bed of large particles, said lower zone being fluidized at a superficial fluidizing-gas velocity greater than about 4 feet per second, said large particles including roughly spherical particles of agglomerated ash matter, b. supplying a gasification medium as fluidizing-gas to said lower zone, said gasification medium being selected from the group of gas mixtures comprising oxygen and steam, air and steam, air and combustion products containing carbon dioxide, and air, c. withdrawing products of the gasification of said fuel together with said fine particles from substantially the top of said upper zone, separating said products of gasification from said fine particles in a cyclone separator, discharging said separated products of gasification, causing said separated fine particles to flow from said cyclone separator into a standpipe, said standpipe conducting said fine particles into a region in which said fine particles are maintained in a slow fluidized state, and causing said fine particles to flow from said region into substantially the bottom of said upper zone at a rate sufficient to maintain a fast fluidized state in said upper zone, d. supplying a gas rich in steam or carbon dioxide and containing substantially no hydrogen or carbon monoxide as fluidizing-gas to said region maintained in a slow fluidized state, and bringing said fine particles intermittently into contact with said gas, and e. withdrawing agglomerated ash matter from the bottom of said lower zone.

Claim 10

The process of claim 7 in which said granulated carbonaceous fuel is selected from the group consisting of caking bituminous coals, and in which said fuel is supplied to said vessel at an elevation intermediate between said top and said bottom of said upper zone.

Claim 11

The process of claim 7 in which said fluidizing-gas in step (d) is selected from the group consisting of steam and carbon dioxide; and including the step of discharging gas from said region separately from said products of gasification in step (c).

Claim 12

The process of claim 7 in which said fluidized bed zones are at a pressure greater than 10 atmospheres.