Chemische Heißgasreinigung bei Biomassevergasungsprozessen
The German goverment decided to increase the percentage of renewable energy up to 20% of all energy consumed in 2020. The development of biomass gasification technology is advanced compared to most of the other technologies for producing renewable energy. So the overall efficiency of biomass gasification processes (IGCC) already increased to values above 50%. Therefore, the production of renewable energy attaches great importance to the thermochemical biomass conversion. The feedstock for biomass gasification covers biomasses such as wood, straw and further energy plants. The detrimental trace elements released during gasification of these biomasses, e.g. KCl, H2S and HCl, cause corrosion and harm downstream devices. Therefore, gas cleaning poses an especial challenge. In order to improve the overall efficiency this thesis aims at the development of gas cleaning concepts for the allothermic, water blown gasification at 800°C and 1 bar (Güssing-Process) as well as for the autothermic, water and oxygen blown gasification at 950°C and 18 bar (Värnamo-Process). Although several mechanisms for KCl- and H2S-sorption are already well known, the achievable reduction of the contamination concentration is still unknown. Therefore, calculations on the produced syngas and the chemical hot gas cleaning were done with a thermodynamic process model using SimuSage. The syngas production was included in the calculations because the knowledge of the biomass syngas composition is very limited. The results of these calculations prove the dependence of syngas composition on H2~C-ratio and ROC (Relative Oxygen Content ). Following the achievable sorption limits were detected via experiments. The KCl containing syngases were analysed by molecular beam mass spectrometry (MBMS). Furthermore, an optimised H2S-sorbent was developed because the examined sorbents exceeded the sorption limit of 1 ppmv. The calculated sorption limits were compared to the limits achievable in experiments. Finally, the hot gas cleaning concepts for both processes were developed on the basis of these results.
info:eu-repo/classification/ddc/620, Heißgasreinigung, Biomassevergasung, Rauchgasentschwefelung, Sorption, Ingenieurwissenschaften, Alkalireduktion, hot gas cleaning, biomass gasification, desulphurisation, alkali reduction
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