CFD Study on Gasification Characteristics of Biomass Pyrolysis Oil = CFD Study on Gasification Characteristics of Biomass Pyrolysis Oil

다국어 초록 (Multilingual Abstract)

Biomass is considered as one of renewable energy sources for future sustainable development of mankind. However, biomass as a fuel is bulky, has a high moisture content and a low energy density so that direct utilization of biomass is fundamentally limited. On the other hand, biomass pyrolysis oil which is obtained by fast pyrolysis of biomass, has high energy density and furthermore is suitable for transport and storage. This biomass pyrolysis oil can be utilized in industry such as heat and power as well as chemical resources. Among them, one application of pyrolysis oil as a feedstock is syngas production by gasification. Generally, syngas means a fuel gas mixture consisting of carbon monoxide, hydrogen, methane and etc. Especially, hydrogen can be used for fuel cell power generation. Several researchers have studied pyrolysis oil gasification by experiment but computational analysis using CFD simulations has not been fully performed.
For these reasons, in the present study, CFD simulation of biomass pyrolysis oil gasification in an entrained flow gasifier was carried out using the computational fluid dynamics code, star-ccm+. In this gasification process, the performance of the spraying nozzle is very important for whole gasification system performance. Hence, first, the spraying characteristics of pyrolysis oil by twin fluid atomizer nozzle were studied. In the present numerical method, droplet vaporization model was considered and the complex gasification reaction mechanisms were adopted. The multi-phase flow was calculated with respect to reaction conditions such as reaction temperature, oxidant equivalence ratio(lower than theoretical oxidant for complete combustion). Finally, the optimum conditions of biomass pyrolysis oil gasification were scrutinized through the product gas distribution, cold gas efficiency, and H2/CO ratio. Also, in order to verify the reliability of the CFD results, it was compared with the biomass pyrolysis oil gasification experiment data.