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Autocatalytic low-temperature conversion of biomass into higher grade hydrocarbons and filtering aids

Das Projekt "Autocatalytic low-temperature conversion of biomass into higher grade hydrocarbons and filtering aids" wird vom Umweltbundesamt gefördert und von Grenzfinanzberatung und Technologietransfer GmbH durchgeführt. Objective: To demonstrate on a large scale a low temperature conversion process for biomass and wastes (more particularly including sewage sludge), to be processed in an economically and ecologically efficient manner to give marketable high grade products. 10500 t/year dry matter will be converted with an estimated payback time of 6 years. General Information: Starting products for low temperature process is biomass containing liquids, proteins and terpenes. These substances will be substantially converted to aliphatic hydrocarbons and carbon by the chemical process of defunctionalization and elimination of heteroatoms. The process takes place under exclusion of air in a temperature range of 190-350 degree of Celsius with participation of catalysts which are already contained in certain grades of biomass (for example in sludge). The process comprises the following stages: - Granulation - Drying - Conversion (subject of the project) - Carbon cooling - Production of energy The process starts with heating and preconversion stage. Products are conveyed from a dry granulate silo into the conversion fluidized bed where they are heated to 350 degree of Celsius (Heat is supplied indirectly via a heat exchanger). Fluidization is performed using the recycled process gases. A salt melt brought to the required temperature in a special heater is used as the heat carrier. On completion of the conversion process, the product is removed via a conveying screw to cooling and storage. Vapours are condensed, oil, fatty acids and reaction water are drawn off and non condensable gases are used for carbon residue cooling and then fed to the carbon residue combustion process. Uncondensed gases are used for fluidization and the surplus process gas (mainly CO2) is also fed to the carbon residue combustion stage. Cooled carbon residue is stored in a carbon silo or drawn off from the process for other utilization (e.g. filter aid). The heating medium used is fuel-oil or natural gas for the period of operation without carbon residue combustion. Total treatment capacity expected is about 1,5 t/hour during 7000 hours/year. Oil yield expected is about 25 per cent of the dry matter and the yield of fatty acids 30 per cent of the oil yield. The process is environmentally satisfactory. Heavy metals are kept as a residue in the carbon; no tar-containing components are produced and no carcinogenic hydrocarbons. The process atmosphere is in a closed circuit with exclusion of air.

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