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The sun as a source of energy.
A photovoltaic or PV plant is a solar power plant that converts part of the solar radiation into electrical power. The solar collectors, also known as solar modules, are important components that are manufactured in solar factories.
Individual solar modules are connected in series according to the size and alignment of the plant. This arrangement summates the voltages of the individual modules. The modules are aligned so that they can trap the greatest possible quantities of light. In Germany, for example, they face south with an angle of inclination of between 30° and 55°. The plants can be designed to run on or off-grid. In on-grid plants, the direct current generated is converted to alternating current by inverters, and fed into the power grid. In off-grid photovoltaic plants, the energy is stored in accumulators.
The EPC Group constructs photovoltaic plants that enable its customer to generate and use electrical energy economically, and in an environmentally friendly way that reduces CO2 emissions. Under the German Energy Feed Act (EEG), the owner is paid for the electricity generated. As general contractor, the EPC Group advises, plans and constructs your rooftop or ground-mounted solar power systems. You are provided with all the services from one source, as we accompany you from the idea, planning and approval stages through to the construction and commissioning of the plant.
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.