Abstract: Method and apparatus for using biofuel or waste material or both for energy production. The biofuel or the waste material is gasified in a fluidized bed gasifier (10), preferably a circulating fluidized bed gasifier. The gas produced in the gasifier is introduced into a boiler (12) equipped with fossil fuel burners (28, 28'28"), typically burners for pulverized coal. The gas is introduced at a level above the burners. Ash from the boiler may be used to form the bed of the gasifier. For control of NO.sub.x, the gas is burned in the upper part of the boiler at a low temperature level of 800.degree.-1050.degree. C. (1472.degree.-1922.degree. F.), preferably 850.degree.-900.degree. C. (1562.degree.-1652.degree. F.), and with a small excess air content of about 5-10 percent. In a second embodiment, the raw gas may be cleaned of harmful or noxious components, and cooled if desired, between the gasifier and the boiler in an additional circulating fluidized bed reactor (152) having a bed of coal ash.

Abstract: Method and apparatus for treating gases issuing from a pressurized gasification or combustion plant of solid fuel prior to leading the gases into a turbine. The hot gases are first cleaned in a particle separator, whereafter they are introduced int a centrifugal separator, which is disposed immediately in front of or in connection with a combustion chamber of the turbine. Cleanliness of the gases is ensured by the centrifugal separator. Air is mixed with the gases for bringing about additional combustion and for raising the temperature of the gases to a level >1000.degree. C.

Abstract: A gas turbine, or like device which utilizes gas and is susceptible to damage from particles greater than a predetermined size in the gas stream, is protected by providing a cyclone downstream of a particle separator. If any particles are in the gas flow downstream of the particle separator--an aberrant condition--the cyclone will remove them and pass them to a particle trap, from which the particles flow to a measuring device. If the measuring device detects a significant number of particles, then an alarm is sounded or corrective action taken. The cyclone may be a horizontal cyclone, or a flow through cyclone.

Abstract: A method and apparatus for gasifying or combusting solid, carbonaceous material a circulating fluidized bed reactor. Particles are separated from the product gas at least in two stages so that in the first stage, mainly coarser, so-called circulating particles are separted and returned to the reactor. In the second stage, fine carbonaceous particulates are separated from the gas and are made to agglomerate at a raised temperature. Coarser particles thus received are returned to the reactor through a return duct together with circulating particles. Adhesion of agglomerating particles to the walls of the duct is prevented preferably by leading hot particulates to the center of the duct and circulating particles to the walls of the duct.

Abstract: A method for gasifying or combusting solid, carbonaceous material in a circulating fluidized bed reactor. Particles are separated from the product gas at least in two stages so that in the first stage, mainly coarser, so-called circulating particles are separted and returned to the reactor. In the second stage, fine carbonaceous particlates are separated from the gas and are made to agglomerate at a raised temperature. Coarser particles thus recieved are returned to the reactor through a return duct together with circulating particles. Adhesion of agglomerating particles to the walls of the duct is prevented preferably by leading hot particulates to the center of the duct and circulating particles to the walls of the duct.

Abstract: A method of and apparatus for gasifying carbonaceous material in a circulating fluidized bed reactor having a lower reactor chamber and an upper reactor chamber interconnected by a throttled throat portion. Carbonaceous material is supplied to a first fluidized bed gasification zone maintained in the lower chamber and is gasified there by a gasifying agent and recycled hot particles separated from the product gas. The effluent from the first gasification zone is passed upwardly through the throttled throat portion to a second fluidized bed gasification zone of the spouting-bed type maintained in the upper chamber to complete gasification of unconverted carbon remaining in the particles entrained in the gaseous effluent from the first zone at a higher temperature than that of the first zone.

Abstract: A fluidized bed reactor where material from a prereactor is brought into contact with hot particles separated from flue gases. The particles when removed from the flue gases by a separator are passed to a prereactor having a gas supply and vapor removal port where the hot particles are mixed with fresh feed material and the mixture is passed to the fluidized bed reactor for chemical and/or thermal treatment.

Abstract: A method of treating materials in a fluidized bed reactor, wherein the material to be treated is brought into contact with hot particles removed from the flue gases coming from the fluidized bed reactor to bring about chemical and/or thermal reactions in the material before it is introduced into the fluidized bed reactor together with recycled particles. Useful components may be recovered in the form of gases, solids or liquids in connection with this treatment.