Abstract:
A method and apparatus for producing a coal/water mixture for combustion in a fluidized bed unit. To produce a hydraulically transportable coal/water mixture, crushed raw coal is preliminarily mixed with water in a first stage. This mixture is final mixed in a second mixing stage. The fine grain-size fraction required for the hydraulic transport is generated in the first mixing stage. The viscosity of the mixture present in the second mixing stage is determined, and as a function thereof additional water is added to the mixture in the second mixing stage, and/or the mixing process in the first mixing stage is altered in order to alter the fine grain-size fraction.
Abstract:
In a method for operating a combination of a gas turbine process and a steam turbine process, in which the superimposed boosted gas turbine process is operated with compressed air and a combustible fluid, and the steam turbine process is operated via a fluidized bed furnace with a carbonaceous solid fuel, whereby the combustion in the fluidized bed furnace is performed with the oxygen-containing exhaust gases of the superimposed gas turbine process and electrical energy is generated with both processes, the efficiency is increased by expanding the exhaust gases of the superimposed gas turbine process only to an extent to which the fluidized bed furnace is operable as a pressurized fluidized bed and subjecting the exhaust gases of the pressurized fluidized bed furnace, after removing solid particles, to a second gas turbine process for further expansion and then to a heat exchange with the compressed air of the superimposed gas turbine process; the air for the superimposed gas turbine process is subjected to a two-stage compression with recooling, whereby the compressing energy for the first stage is derived from the second gas turbine process and the compressing energy for the second stage is derived from the superimposed gas turbine process.
Abstract:
A fluidized bed combustion system that can be operated or controlled under pressure is provided. To eliminate the erosion or abrasion to which heat exchangers located in a fluidized bed combustion chamber are subjected due to the flue dust contained in the flue gas, no thermal withdrawal or exchange takes place in the combustion chamber of the inventive fluidized bed combustion system, although the reaction conditions remain the same. At least one controllable line for returning to the combustion chamber part of the flue gas, if necessary cooled by heat exchangers variously arranged outside the combustion chamber, branches off from the flue gas line downstream of a dust separator that is disposed in the flue gas line downstream of the combustion chamber. The main area of application is the production of electrical energy and heat for the generation of steam, as process heat, or as heat for a remote site, by means of a fluidized bed combustion system that can be operated or controlled under pressure.