Power plant with cyclone cleaners having cooled cyclone legs

Claim 1

A power plant in which fuel is burnt in a fluidized bed of particulate material at a pressure exceeding atmospheric pressure comprising a pressure vessel, a bed vessel inside the pressure vessel, means to feed fuel to be burnt to the bed vessel, an air distributor with nozzles locted within the bed vessel, means to feed pressurized air to the air distributor to create a fluidized bed in which the fuel is burnt, at least one cyclone within the pressure vessel, means for leading combustion gases from the bed vessel to the at least one cyclone, a pressure reducing ash discharge system for the removal of separated ash from the at least one cyclone, a turbine which is driven by combustion gases cleaned in the at least one cyclone outside said bed vessel but inside said pressure vessel, and a compressor for the compression of combustion air supplied to the pressure vessel in which said cyclone at its lower end is connected to an elongated downwardly extending tubular leg communicating with said ash discharge system, a cooling jacket surrounding said cyclone leg to form a channel for a cooling medium around the leg and within the jacket, an inlet at one end of said channel communicating with the space in said pressure vessel containing pressurized combustion air and an outlet for said cooling medium at the other end of said channel.