Process costing and analysis is best accomplished with rigorous chemical process simulation software such as Aspen-Plusİ (Aspen Technology, Cambridge, MA). Processes that convert biomass feedstock to liquid fuels are unfortunately difficult to simulate due to the chemical complexity and lack of data for thermodynamic and other properties of the feedstock and products. To overcome this problem, the pyrolysis of switchgrass to bio-oil was modeled in Aspen-Plusİ using a simplified switchgrass composition and simplified set of pyrolysis and gasification reactions that could be adjusted to agree with measured data. (1) Thus modeled, the process was scaled-up and evaluated for feasibility. The simulation is potentially applicable to thermochemical conversion strategies that optimize production of any of the three products, syngas, bio-oil and char from biomass feedstocks.

(1) A. A. Boateng, D. E. Daugaard, N. M. Goldberg and K. B. Hicks. Bench-scale fluidized-bed pyrolysis of switchgrass for bio-oil production. Ind. Eng. Chem. Res. 46:1891-1897 (2007).