Produktdesign disperser Rohstoffe durch chemische Reaktionen

During the recovery and processing of materials from natural resources reactions between ground raw materials and fluid media take place. Starting materials are mineral and fossil substances, e.g., ore and coal, and renewable resources. In the physical model the particles shrink during the reaction. The design of the formed particles depends on the deposit, type and quantity of impurities, on further pre‐treatments and the disperse properties of raw materials. Molten materials can be purified, doped and shaped. Otherwise, particles formed from powders, granular or fibrous materials show a completely different chemistry after the reaction, but largely kept size and shape of the starting material. Others disperse properties such as bulk density, density and flow properties, are changing by the reaction. For additional product design (cleaning, shaping) downstream processes are required.     

Niederdruck-Polyethylen: Einfachere Verfahren durch hochaktive Katalysator-Systeme

High density polyethylene (HDPE): simple processes with high mileage catalysts. Introduction of highly active catalytic systems considerably simplified the technical processes for polyethylene production with transition metal compounds (Ziegler process). The requirements for these catalysts are discussed and experiments and models are presented to show how these catalytic systems work in the industrial process. These investigations demonstrate that it is our detailed knowledge of some essential processes which has improved process control in the plant.     

Elektrochemische Energieumwandlung in Brennstoffzellen

Electrochemical energy conversion in fuel cells. With the exception of high temperature fuel cells, fuel cells burn hydrogen fuel exclusively at low temperature giving energy conversion efficiencies of 40 to 60%. Alkaline cells, phosphoric acid cells, and membrane cells operate at low temperatures, whereas molten carbonate cells and zirconium dioxide membrane cells are designed as high temperature cells. The alcaline fuel cell has so far been used only for special purposes, such as space missions and miltary applications. The phosphoric acid cell is suitable for modular heating plant between 0.5 and 5 MW which are fueled with natural gas. It has demonstrated its technical reliability in a large-scale field test in the USA and an economical breakthrough is expected in the next few years. The two high temperature cells face a longer development phase, yet hold promise of better econmic performance thanks to their greater efficiency.