A fluidized combustor is provided with a burning zone having cooling passages in its upper portion and a lower portion beneath said passages yet deep enough so that material therein may be operated in a fluid bed combustor mode with cooling by fluidizing excess air, a separate zone being provided for selective storage therein of materials transferred from the burning zone.
A multibed fluidized boiler having at least two fluidizable beds, in which conventional fuel, for example coal, is supplied to the first bed and in which the combustion of this fuel takes place in the first bed and in the following bed. An alternative fuel, such as wood chips, waste wood or paper, or combustible refuse, is adapted to be supplied to the second bed in order to be burnt there, thus obtaining a simplified fuel feeding to the second bed and increased protection against clogging of the nozzles for the supply of gas from the first bed to the second bed.
The invention relates to a method of igniting, upon start-up, a combustion chamber (8) in a power plant with combustion of fuel in a fluidized bed (14). The air flow through the nozzles (13) of the combustion chamber bottom (12) for fluidization of the bed (14) and for combustion of the fuel can be reduced upon start-up; bed material, which is heated to the ignition temperature of a start-up fuel, is transferred from a storage container (40) to the combustion chamber (8), and fuel is supplied to the bed (14). In those cases where the air flow has been reduced during the transfer of the bed material, it is increased again when the fuel is supplied. The invention also relates to a power plant having means for temporarily bypassing the nozzles (13) of the combustion chamber bottom (12) while transferring hot bed material from a storage container (40) to the combustion chamber (8), and a fuel system (30-38) for the supply of fuel to the combustion chamber (8). In a plant with a combustion chamber (8) enclosed in a pressure vessel (10), a connection with a valve (55) for by-passing the air flow may be provided between the space (11) in the pressure vessel and the freeboard (18) of the combustion chamber (8) for reducing the air flow through the bed. Further, control means (38, 80) are provided for carrying out the necessary operations of valves, and the like, during the start-up operation.
A boiler plant with a multi-fluidized-bed combustion chamber comprising a first bed in a lower combustion space and a second bed in an upper combustion space and with nozzles in the support means for the beds for injection of combustion air into the first bed and combustion gases into the second bed for fluidization of the bed material therein. The plant is equipped with bed material transport devices for transferring bed material from the lower combustion chamber to the upper combustion chamber or vice versa. Further, measuring means is provided for measuring the temperature and depth of the lower bed, and signal processing and control means are provided for adapting the depth of the lower bed in dependence on plant load and bed temperature.
An integral generator/gasifier system in which a vapor generator is provided that includes an upright furnace section and a plurality of nozzles, each having one end registering with the interior of the furnace section. A gasifier extends adjacent to the furnace section and supports a bed of adsorbent material for the sulfur generated as a result of the gasification of fuel introduced to the gasifier. Air is passed through the bed of adsorbent material to fluidize said material so that, upon gasification of the fuel, a substantially sulfur-free product gas is produced. The other ends of the nozzles communicate with the gasifier so that the product gas passes from the gasifier through the nozzles and into the furnace section for combustion.
