The policy of the European Green Deal has the long-term aim of creating a CO2 neutral energy supply system, which requires not only a clean energy production but also a shift towards a circular economy. Expected increase in energy demand, local and global limitation of high quality fuel resources and emission of gases with climatic relevance resulting from the utilization of fossil fuels represent the main challenges for future sustainable and stable energy supply and production chains. Therefore, future systems for energy production will be characterized by increased use of renewable, volatile energy sources (wind, solar) combined with utilization of low-grade waste-based and biogenic fuels. Typical low-grade fuels feature high heterogeneity, low calorific value and high content of inert material and trace species. In order to be utilized in highly efficient conversion processes with high fuel- / load- and product-flexibility, these fuels must be converted to high quality, process adapted chemical energy carriers.
Gasification is a process for conversion of low-grade solid and liquid fuels to a high quality fuel (syngas) and is therefore a promising technology to enable a sustainable energy system together with a closed anthropogenic carbon cycle. The main advantage of gasification based processes is the great flexibility on both the feedstock side and the product side, which makes gasification an interface technology for the projected changes in energy sector and industry. A wide spectrum of feedstocks e.g. biogenic, agricultural, industrial or municipal residues can be used to produce syngas. Syngas can then be deployed in a manifold of processes, ranging from energetic use for generating heat and electricity to the synthesis of complex chemicals, e.g. substitute fuels or synthetic materials.
Depending on the end use, different gasification processes can be utilized in order to establish a conversion process with maximum efficiency to be integrated into the respective process chain. The oxygen-blown entrained flow gasification process is operated at high temperatures and high pressure, yielding a tar-free synthesis gas. The high pressure level and the absence of tars make the syngas well suited for catalytic processes, where it can without further compression directly be converted to basic chemicals (e.g. methanol), to liquid fuels (e.g. gasoline) or polymers. The dual fluidized bed process, which is operated at lower temperature and atmospheric pressure, yields a high heating value syngas. This product gas can be conditioned to be used in chemical synthesis and CHP-systems.