Mikrostrukturen für die katalytische Wasserstofferzeugung aus Ethanol

Hydrogen for fuel cell applications has been generated by catalytic steam reforming of ethanol in microstructures. The influence of reaction temperature, contact time and molar ratio steam to carbon (S/C) on the reaction has been investigated. The Co/ZnO catalyst coated on the microstructure showed high activity and selectivity. The hydrogen yield obtained was up to 5.2 mol mol^–1 ethanol. Ethanol has been completely converted at short contact time (W/F 25 g min mol^–1) and 600 °C at S/C ratio between 4.9 and 6.5.     

Mischer mit mikrostrukturierten Folien für chemische Produktionsaufgaben

Mixers with Microstructured Foils for Chemical Production Purposes Since about 10 years the Institut für Mikrotechnik Mainz GmbH (IMM) is engaged with the application of microstructures for chemical micro process engineering. Their advantages – more efficient heat exchange and mass transport – lead to, among other things, an increase in yield and selectivity even while saving resources. The development of microstructured mixers thereby played a key role for carrying out advanced syntheses of fine chemicals as well as for the generation of dispersions, creams, foams, and emulsions. So far, microstructured mixers were mainly limited for laboratory‐scale or at best pilot plant‐scale – typical maximum flow rates were from 2 – 100 L/h for watery fluid systems. With the introduction of the StarLaminators StarLam300 and StarLam3000 this barrier could be lifted far beyond 300 L/h up to the m³/h domain. Both apparatus yield at high flow rates a mixing efficiency which reaches the high performance of today's low‐capacity (L/h) micro mixers. Therefore, continuity from the ”?real”? micro mixers over the herein described high‐throughput tools to conventionally manufactured static mixers with even higher flow rates is given.     

Membranen für Polymerelektrolyt‐Brennstoffzellen

Membranes for Polymer Electrolyte Fuel Cells The polymer electrolyte membrane is the heart of hydrogen fuelled Polymer Electrolyte Fuel Cells (PEFC) and methanol fuelled Direct Methanol Fuel Cells (DMFC). Membranes of sulfonated fluoropolymers are already commercially available. Important goals for research and development are for PEFCs an increased operating temperature without the need for additional humidification and for DMFC the reduction of methanol transport through the membrane. The use of non‐fluorinated polymers aims at a reduction in membrane cost and environmental hazards. Membranes already in industrial product development are considered as well as novel membrane concepts in fundamental research.     

Wasserstofferzeugung für die Hydrierung von Fetten und Fettsäuren

Production of Hydrogen for the Hydrogenation of Fats and Fatty Acids A process is described for the production of highly pure hydrogen from hydrocarbons, such as natural gas, liquefied gas and light petroleum. The process consists of following three steps: 1. Desulfurization of the starting material; 2. Conversion of hydrocarbons into permanent gases by splitting with steam at high temperatures; 3. Separation of other gases from hydrogen by adsorption. This process has been tested commercially. With increasing cost of transport, and owing to regulations for the transport of hydrogen, which are difficult to fulfil, the aforesaid process offers an attractive alternative to the consumer of hydrogen. Cost of investment, energy consumption and economy of the process are dealt with.     

Mikroreaktoren aus Glas für die Anwendung im Labor

The implementation of microreaction technology as part of academic research und hands‐on trainings requires economic und manageable microstructured devices. Glass microdevices are an alternative to round bottom flasks in chemical synthesis. Integration in existing systems is provided by use of standardized adapter.     

Expertensysteme für die Prozeßführung,–Erfahrungen aus dem Verbundprojekt TEX-I

Expert systems for process control – experience with the TEX-I project. The paper gives a brief overview of some topics concerned with expert systems technologies in a real-time environment. After a four-year-project the perspectives of the technology are much more realistic, and the promises more or less reduced. What we see is a software-technology that is hard to use but well suited for complex applications. Unsolved is the problem of knowledge elicitation, the bottelneck of knowledge engineering.