Jakob Köchermann

Organosolv pulping processes are able to generate liquid hemicellulose fractions with a low cellulose and lignin content. Utilization of such streams is promising for production of high-value chemicals. In this study, on the basis of three reaction models, kinetics of an aqueous organosolv hemicellulose and D-xylose conversion into furfural was examined at temperatures between 160 and 200 °C using a continuous tube reactor. Furthermore, furfural degradation was investigated to consider the self polymerization. Results were compared with previous studies and differences are discussed. Kinetic models showed slight differences for D-xylose conversion and stronger deviations for furfural formation. Overall, model 3, which includes the formation of a xylose intermediate, showed the best performance concerning the experimental results. Differences between D-xylose and organosolv hemicellulose conversion can be attributed mainly to sugar oligomers.

For the design and optimization of methfanation processes detailed modeling and simulation work is advisable. However, only a few kinetics published in literature rely on wide temperature and pressure ranges, which are prevalent at modern methanation applications with dynamic operation. Especially the simulation‐based design of methanation processes with commercial catalysts is difficult due to legal restrictions regarding the publication of kinetic data of those catalysts. In this work, rate equations for the dynamic modeling and simulation of methanation processes operating with commercial Ni/Al₂O₃ catalysts are selected, adapted, and tested in a dynamic reactor model. The results suggest that the catalyst's nickel content is an indicator for the choice of a rate equation. Testing of the equations in a reactor model meets published data for CO and CO₂ methanation and own measurements.