DEVELOPMENT OF A ZERO-EMISSION CARBON FUEL CELL USING HYDROTHERMALLY CARBONIZED BIOMASS AS FUEL

摘要

Anthropogenic green house gas emissions have increased markedly since the beginning of the industrialization in the 18th century. Due to this development there are inevitable implications onto to the world climate. Besides methane or nitrous oxides, carbon dioxide is the most important anthropogenic green house gas. Its origin lies both in changes of land-use, e.g. deforestation, and - primarily - in the use of fossil fuel, e.g. for the generation of energy. Thus one key to alleviating the global effect of the climate change is the discovery of new, sustainable and emission-free energy sources. One possibility and solution under discussion is the use of biomass schemes - yielding in a zero-emission-balance of greenhouse gases.Hydrothermal carbonization is applied for processing biomass. The carbohydrate dispersions are heated for 4-24 h to temperatures around 200 °C, resulting in dehydration leading to a carbonaceous material with a chemical composition similar to lignite in form of spherical, micrometer sized particles.We intended to use these water dispersible carbon microparticles as a novel type of fuel in a carbon fuel cell. In contrast to the widely known concept of a direct carbon fuel cell, an indirect oxidation process by a secondary redox system (Fe~(3+)/Fe~(2+)) is used allowing a low-temperature setup. The Fe~(3+) is oxidizing the carbon, while the resulting Fe~(2+) is re-oxidized at the anode to produce an electric current. First experiments concerning the feasibility of hydrothermal coal to get oxidized and first efforts to apply it for the generation of electric current have been successful, proving the high potential of this new method of energy recovery.