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Biogas plants. Environmentally friendly and worthwhile investment.
Biogas plants are an environmentally friendly and worthwhile investment for local authorities, agricultural businesses and waste disposal companies in Germany and other countries. The Amendment to the German Renewable Energies Act has extended the state subsidization of the generation of energy from liquid and solid manure, residues and energy plants.
With the aid of detailed preliminary studies, individual process development, correct applications to the local authorities, short delivery, construction and commissioning times, we take advantage of all the possibilities of obtaining subsidies and optimizing your biogas plant. This includes choosing a suitable location and the locally available raw materials, as well as optimal use of the waste heat.
Turnkey biogas plants from EPC guarantee stable fermentation processes with maximum yield, minimal operating costs and maximum operational safety. The system solution from EPC for fermenting feedstocks comprises a single-phase, mesophilic biogas plant, which uses a continuous wet fermentation process. In wet fermentation, the fermenting substrate remains stirrable and flowable so that it can be thoroughly mixed during the process, thus ensuring a good exchange of nutrients and energy between bacteria and substrate. The residue from this fermentation process is then used as an agricultural fertilizer.
The method of producing ultrapure silicon from metallurgic silicon is based on the thermal decomposition of highly pure, rectified chlorosilanes or silanes to form silicon with the separation and recycling of gaseous byproducts. The conventional commercial technology passes through the stage of producing trichlorosilane in a fluidized-bed reactor from metallurgic grade silicon and hydrogen chloride. The trichlorosilane is then subjected to multi-stage rectification until the purity required for the desired application is reached (solar grade or electronic grade). The thermal decomposition of trichlorosilane in a chemical vapor deposition (CVD) reactor to form silicon at 900 °C creates a mixture of gaseous by-products, which have to be prepared for recycling (vent gas recovery) back into the process. We have optimized the process for producing ultrapure silicon from monosilane. It now offers a significantly higher efficiency as temperatures are only around 600 °C, and the collection efficiency has been increased to almost 100% in comparison to the mere 25% achieved by conventional processes. Monosilane is obtained by the disproportionation of trichlorosilane and recirculation of the disproportionation products. Trichlorosilane is thus required in both methods.
The gas mixture produced by the thermal decomposition of trichlorosilane in a chemical vapor deposition (CVD) reactor has to be separated into its constituent parts before the individual products can be recirculated. The monosilane method does not need these cycles, however Vent Gas Recovery is still part of our range or products.
The monosilane synthesis gas is stored temporarily in vacuum-insulated containers prior to further processing or filling. The containers are equipped with a pressure build-up vaporizer and an internal cooling coil to facilitate cooling. The containers are a special product of our subsidiary company, CRYOTEC, which specializes in special cryogenic applications.
Silicon tetrachloride is the main by-product of both the production of trichlorosilane from metallurgic silicon with HCl in a fluidized-bed reactor and the disproportionation of trichlorosilane. The thermal decomposition of trichlorosilane in a CVD reactor also creates large quantities of silicon tetrachloride. The silicon tetrachloride is converted with hydrogen into trichlorosilane in a conversion reactor. This process can be run homogeneously with hydrogen at approximately 1,000 °C in graphite reactors. We use the more elegant heterogeneous method of controlling the process by feeding silicon into a fluidized-bed reactor.