The Biomass-to-Syngas (BTS) chemical looping process is an efficient thermochemical gasification process for the conversion of biomass to syngas via partial oxidation. The BTS process combines an iron-titanium composite metal oxide (ITCMO) oxygen carrier and a unique gas-solid co-current moving bed reducer design. The thermodynamics of the ITCMO oxygen carrier favors the controlled partial oxidation of the biomass feedstock and, hence, the generation of high purity syngas with minimal full oxidation products. Density functional theory (DFT) simulation studies are performed to unveil the role of oxygen vacancy in partial oxidation reactions of biomass volatiles on oxygen carrier surfaces. The gas-solid co-current moving bed reducer operation ensures a sufficient gas and solid residence time for the full conversion of biomass volatiles and char, resulting in a syngas composition that is close to the thermodynamic equilibrium. The addition of steam to the system can adjust the composition of the syngas product to a desired H2:CO ratio for the downstream chemical and fuel synthesis. Compared to the conventional biomass gasification processes, the BTS process eliminates the need for an air separation unit (ASU), a tar reformer, a steam reformer, or a water-gas-shift (WGS) reactor, resulting in an increased process efficiency and decreased costs. The BTS process is experimentally tested in a bench scale moving bed reducer. The composition of syngas, including tar content, is quantified. The results confirm that the BTS process is capable of producing high purity syngas with adjustable H2:CO ratio, and that the ITCMO oxygen carrier can effectively crack and convert tars from biomass. A techno-economic analysis (TEA) focused on a biomass to methanol plant using the BTS process is conducted by Nexant, which shows an increased process efficiency and decreased methanol required selling price. Thus, the development of the BTS process will lead to an economically competitive biomass gasification technology with reduced the cost for fuel and chemical production from biomass.

Thermochemical gasification of biomass using the biomass-to syngas chemical looping process

255th National Meeting (2018)

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