OSU Biomass to Syngas (BTS) technology uses moving bed Reducer reactor to gasify the biomass into syngas and fluidized bed Combustor reactor for air regeneration. The work presents the scale-up results of the BTS process on a sub-pilot scale (~15 kWth capacity) with smooth operation cumulatively for over 700 hours. The demonstration has successfully tested three types of as-received biomass: pelletized corn cob, woody pellets, and unpelletized loose corn cob, thus proving the robusticity of the process to handle untreated biomass with a batch-to-batch variation. Avariable syngas quality with an H2/CO ratio of ~2, and a syngas purity greater than 70% was achieved, which can then be used to generate the liquid fuels in the Fischer-Topsch (F-T) process. Process simulations show the system can achieve a ~14% reduction in the biomass requirement compared to the conventional biomass gasifier for an equal liquid fuel generation basis. Heat integration suggests that an overall autothermal process can be achieved by using the heat from combustor exhaust for biomass drying. The sub-pilot results suggested that a lower reactor volume can be adequate for complete gasification, and there exists a minimum steam flowrate beyond which the char gasification kinetics in the biomass system is not dependent on the steam flowrate. Further bench-scale experiments are conducted to optimize the reactor size and steam flowrate during gasification. The experiments show a volume reduction of nearly 67%, with a minimum steam flowrate being as low as 5% of the inlet carbon flow rate for woody biomass pellets.