Hydrogen generation in micro structured reactors
Today, process intensification and sustainability are pushing the development of new chemical processes. One of the major challenges of the 21st century is to overcome the dependency on fossil fuels for power generation by the use of renewable energy sources. In the Micro Reaction Engineering Group new technologies are developed for the use of renewables such as bioethanol or acetic acid for power generation. A joint research project was engaged with the development and market launch of an innovative and compact power generator from propane or bioethanol based on solid oxide fuel cell (SOFC) technology. Bioethanol, a nontoxic fuel which is easy to store and to transport, is of increasing interest under renewable fuels. A H2 and CO rich fuel gas is generated by catalytic partial oxidation of bioethanol. In this project a low cost, long-time and high-temperature stable catalyst based on Ni or Co for the conversion of ethanol with air was developed. By using the non-precious catalyst a hydrogen yield of 90 % was achieved at complete ethanol conversion. A syngas with 37 vol% H2, 26 vol% CO, 3 vol% CO2, and 1 vol% CH4 was obtained, which is directly used for power generation in SOFC at a temperature of 850 °C. The immobilization of the developed catalysts on micro structured cordierite monoliths was an essential requirement for the commercial application in the fuel cell system of the project partner new enerday GmbH. Monolithic reactors are particularly advantageous for strongly exothermic reactions, because heat transport can be more favorable and the pressure drops are greatly reduced. Therefore, the risk of thermal runaway and catalyst deactivation is reduced. We developed a dip-coating method resulting in homogenous, thermally and mechanically stable catalysts based on ceramic honeycombs.