Objective Design and construction of a coal fired power plant based on a combined cycle technology successfully applied to combustion of widely varying fuels for the purpose of steam generation and power production under environmentally acceptable conditions and net efficiency of more than 40% for small plants ( 40 MWe) and a net efficiency of more than 45% for large plants (< 100 MWe).All results of the design work are speaking in favor of the circulating mode for a direct coal fired pressurized fluidized bed combustion system. This applies especially to the plant efficiency and the plant costs which were compared. One of the strength of the present results of the demonstration project is, that a demonstration plant of 50 MWe - 100 MWe can be build.For clean gaseous and liquid fuels, combined cycle power plant engineering has in the meantime be accepted. This technology is less expensive and more efficient than that of conventional power plants. If coal is to be used in combined cycle power plant, efficient fuel gas and/or flue gas cleaning is an indispensable requirement. A direct and simple procedure to burn coal under pressure and than clean the flue gases at combustion temperature and combustion pressure with directly following expansion of the flew gas in a gas turbine with high thermal efficiency is the pressurized fluidized bed combustion of coal.Within the project the design of a bubbling pressurized fluidized bed combustor and the design of a circulating pressurized fluidized bed combustor was investigated as a basic for the realisation of a demonstration plant.In the bubbling pressurized fluidized bed combustor heat release and heat transfer are simultaneously taking place in the fluidized bed. This approach is attractive for it leads to very compact solutions. However, the complex requirements resulting from combustion, emission control, heat transfer, part load operation and dynamic process also entail some disadvantages. This comprises are not so notable in the circulating fluidized bed combustion due to separation of functions.In case of bubbling pressurized fluidized bed combustor, the entire combustion air flows through the fluidized bed. With due regard to possible erosion, the fluidizing velocity is limited to 1 m/sec, resulting in a relatively large cross section of the fluidized bed and a large pressure vessel diameter.In the circulating pressurized fluidized bed combustor, the combustion reactor does not contain any immersion-typ heating surfaces. Thus, the fluidizing velocities can be increased to up 5 m/sec which reduces the vessel diameter accordingly.The fluid bed heat exchanger for the circulating pressurized fluidized bed combustor can be conceived at discretion as regards its height/diameter ratio, owing to the small particle diameter of the circulating ash, the fluidizing velocity is here below 0.3 m/sec. Erosion problems are not anticipated in contrast to bubbling pressurized combustion systems.In bubbling pressurized fluidized bed combustion, the bed temperature is given for kinetic-reaction reasons. The transfer coefficient depends on the mean particle diameter and, as a result on the fuel preparation. Thus, dimensioning of the bed heating surface also depends on the fuel and its particle size. Adjustments may be required from case to case.The fluid bed heat exchanger of the circulating pressurized fluidized bed combustor does not need to operate with a constant temperature difference. Changes of the heat transfer coefficient for different fuels or fuel treatments can be offset by the variable temperature difference. Adjustment of the heating surface is not necessary. The heating surface can be dimensioned in a relatively wide tolerancerange. Programme(s) ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985 Topic(s) 7.2 - COMBUSTION INTEGRATED TO THE END-USE CYCLE Call for proposal Data not available Funding Scheme DEM - Demonstration contracts Coordinator DAWID-SAAR EU contribution No data Address DUISBURGER STRAßE 375 46049 OBERHAUSEN Germany See on map Total cost No data
