Pyrolysis reactions and reactions of pyrolysis products in Sorption Enhanced Biomass Gasification in a Calcium Looping System

• Applicant: Professor Dr. Günter Scheffknecht
• Subject Area: Chemical and Thermal Process Engineering
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 411441519

In contrast to other gasification processes, sorption enhanced gasification (SEG) allows for the direct production of hydrogen or of a syngas with a tailored composition. Due to in-situ capture of CO2, the SEG process omits the requirement of an additional shift reactor to convert CO to H2. When operated with biogenic fuels, the SEG process can produce renewable hydrogen or other renewable fuels or chemicals. This illustrates the process’ potential when aiming to reduce the current dependency on fossil oil and gas. The SEG process has been rapidly developed from lab to pilot scale in recent years. Even though, the process’ applicability has been demonstrated successfully, a number of fundamental questions involving biomass conversion and especially biomass pyrolysis and subsequent reforming reactions remain open and hinder the further optimization and in consequence the commercial application of the SEG process. The PyroSEG project aims to resolve those issues following a comprehensive approach with fundamental investigations on primary biomass pyrolysis and subsequent secondary reactions of the pyrolysis products under SEG specific conditions at a Macro-TGA and a laboratory scale bubbling fluidized bed system. Moreover, the influence of the sorbent and char on tar-cracking and reforming of pyrolysis products will be studied. Other reactions of the SEG process such as char gasification and sorbent carbonation have been described relatively well in the past and hence will not be investigated in detail in PyroSEG. In addition to pyrolysis reactions, in PyroSEG the hydrodynamics of a fluidized bed containing a mixture the limestone sorbent and biomass char will be experimentally analyzed, focusing on effects such as char and bed segregation. Based on extended and new empirical data, advanced process models will be developed, allowing a more accurate and detailed simulation of the process and its improvement in respect to efficiency and syngas quality. Results of such simulations will be compared to experimental SEG results from experiments conducted in a dual fluidized bed (DFB) system within the scope of other research projects. The models developed in PyroSEG will be powerful tools to extrapolate research results to a larger scale application and to tailor the process design to certain conditions (i.e. variable types of biomasses or syngas utilization routes). Samples and other results from the conducted experiments will be jointly analyzed and evaluated by both project partners. Throughout the project, the partners will work in a close collaboration and will share and discuss experiments and results. This will involve dedicated mutual research visits and other regular personal and telephone meetings. The project aims to disseminate its results in at least four (two of those joined) peer reviewed papers.

• DFG Programme: Research Grants
• International Connection: China
• Partner Organisation: National Natural Science Foundation of China
• Cooperation Partner: Professor Dr. Ningsheng Cai