초록 ▼

A high efficiency economical coal fired combined cycle power generation system and process is described. The system utilizes a circulating fluid bed ("CFB") coal devolatilizer which is fluidized with recycled coal volatiles. The devolatilizer is heated indirectly with hot bed material from a convent

A high efficiency economical coal fired combined cycle power generation system and process is described. The system utilizes a circulating fluid bed ("CFB") coal devolatilizer which is fluidized with recycled coal volatiles. The devolatilizer is heated indirectly with hot bed material from a conventional CFB boiler burning the devolatilized coal (char). The CFB boiler is fluidized by gas turbine exhaust gas. The ratio of high efficiency/low capital cost Brayton cycle (gas turbine) power output to lower efficiency, higher capital cost Rankine cycle (steam turbine) power output is maximized by concurrently and/or successively preheating the gas turbine compressor discharge with; (1) gas turbine exhaust (recuperator), (2) hot coal volatiles exiting the devolatilizer, (3) coal char CFB boiler hot bed material (with either an external or internal heat exchanger), and (4) CFB boiler flue gas. The process and method described produces a thermally cracked, clean product gas with a high Btu content (.about.500 BTU/SCF) and is, therefore, readily usable in gas turbines which are designed for natural gas without design modification. This high Btu product gas also reduces fuel gas cleaning volume and fuel gas sensible heat loss. The product gas yield and/or the devolatization reaction temperature is increased by either partially substantially or supplementing the fluidizing gas with steam and/or air or oxygen.

대표청구항 ▼

[ What is claimed is:] [1.] A process for generating power from a volatile containing carbonaceous feed, comprising:a. providing first and second fully entrained flow circulating fluidized bed reaction zones through which a loop of heat-conveying materials continuously circulate and being fluidized

[ What is claimed is:] [1.] A process for generating power from a volatile containing carbonaceous feed, comprising:a. providing first and second fully entrained flow circulating fluidized bed reaction zones through which a loop of heat-conveying materials continuously circulate and being fluidized by first and second fluidizing gases, respectively;b. introducing a volatile-containing carbonaceous feed into said first fully entrained flow circulating fluidized bed reaction zone;c. heating said volatile containing carbonaceous feed with said heat-conveying materials, for a time period sufficient to produce a product gas comprised of partially thermally cracked volatiles and substantially devolatilized feed, said heat-conveying material entering the first reaction zone at a first temperature between about 1000.degree. F. and about 2400.degree. F. and exiting at a second temperature lower than said first temperature because of the endothermic heat requirements of said first reaction zone;d. separating said substantially devolatilized feed with said heat-conveying materials from said product gas;e. either increasing product gas yield or devolatilization reaction temperature in step c by at least partially substituting or supplementing the fluidizing gas with steam and/or air or oxygen;f. introducing into said second fully entrained flow circulating fluidized bed reaction zone said substantially devolatilized feed together with said heat-conveying material from step e and, as said second fluidizing gas, an oxygen containing turbine exhaust gas;g. exothermically reacting said substantially devolatilized feed in the presence of said oxygen-containing turbine exhaust gas at a temperature above the temperature of said first fully entrained flow circulating fluidized reaction zone for a time period sufficient to substantially combust said substantially devolatilized feed, produce a flue gas, preheat a compressed air feed for a gas turbine, generate high pressure steam conveyed to a steam turbine to provide power and elevate the temperature of said heat-conveying material from said second temperature to a temperature equal to or greater than said first temperature;h. separating elevated temperature heat conveying material in step g and conveying a portion of said elevated temperature heat conveying material to said first reaction zone;i. compressing a portion of said product gas from step e and forming a compressed product gas;j. providing compressed air from a gas turbine compressor;k. introducing said compressed product gas and said compressed air into a gas turbine combustor, combusting said compressed product gas and said compressed air in said gas turbine thereby providing power and an oxygen containing turbine exhaust having a temperature of at least 800.degree. F. to about 1200.degree. F.; andl. recycling said oxygen containing turbine exhaust gas of step k to said second fully entrained flow circulating fluidized reaction zone as said second fluidizing gas.