Even in the climate-friendly energy system and sustainable economy of the future, carbon-based secondary fuels (C fuels) and basic chemical materials will be required. Biomass is the only renewable energy source that contains carbon (C). As arable land, and therefore biomass are limited, biomass must be used efficiently and sustainably as a future C resource. The integration of hydrogen (H2) from electrolysis, which is produced out of water using power from renewable energy sources, offers great potential to optimise the production of C fuels from biomass.
Adding hydrogen to the thermochemical conversion process uses the carbon stored in the biomass to its full extent. As a result, it significantly reduces the amount of arable land specifically used for C fuel generation. In comparison to the biofuels that are commonly available today (e.g. bioethanol, biodiesel), the fuel yield is up to six times higher when producing substitute natural gas (SNG) or methane (CH4). In turn, that reduces arable land use by 80%.
Above is a process diagram of the AER process (Absorption Enhanced Reforming) that was developed at ZSW. Biomass is converted thermochemically using steam and the resulting CO2 is immediately separated by a limestone-based, CO2-absorbent fluidised bed material. This process creates a hydrogen-rich product gas that in the form of synthesis gas simplifies the production of C fuels, such as SNG, by way of suitable process management.
In order to maximise the C fuel yield from biomass, ZSW’s research and development department focuses on innovative fluidised bed processes for the thermochemical conversion of various biomass types, in particular biogenic residues and waste. In addition to developing new processes, technical and economic development, optimisation by way of experimental testing, and megawatt scale simulation-aided process design take centre stage in the research. Thanks to the 20 kilowattth fluidised bed test platform equipped with comprehensive measurement technology, one and two-bed fluidised bed processes with auto process management or allothermic process management can be studied and adapted for efficient C fuel generation (with and without H2 incorporation). Complemented by a high quality laboratory infrastructure, our expertise encompasses the selection, development and recommendation of limestone-based, chemically active fluidised bed materials, which do not only allow mineral-rich fuels to be used, but also closes the natural nutrient circle.