What is the production cost of renewable diesel from woody biomass and agricultural residue based on experimentation? A comparative assessment

This study explores the technical and economic potential of three Canadian biomass feedstocks (spruce, corn stover and wheat straw) to replace petro-diesel through the production of renewable diesel and gasoline via fast pyrolysis and hydroprocessing. A detailed data-intensive process and cost model for a 2000 dry t d(-1) plant capacity for two scenarios (hydrogen production and hydrogen purchase) was developed using both experimental and published data. The authors analyzed the quality and quantity of bio-oil, which acts as an intermediate for renewable diesel, by performing fast pyrolysis experiments in a lab -scale fluidized bed reactor at temperatures of 400-520 degrees C and three particle size distributions. The production costs of renewable diesel are 0.98 $ L-1,1.11 $ L-1, 1.19 $ L-1, and 1.27 $ L-1 for the spruce hydrogen purchase, spruce hydrogen production, corn stover hydrogen production, and wheat straw hydrogen production scenarios, respectively. The net energy ratios (NERs) of the process, which is the ratio of the energy content of the output product to fossil fuel inputs, were calculated to be 2.16, 1.5, and 1.16 for spruce, corn stover, and wheat straw, respectively. The effects of byproduct selling price on renewable diesel cost were also investigated. As the results suggest, the yields of renewable diesel and gasoline depend on the amount of bio-oil produced through fast pyrolysis followed by the properties of biomass. From the sensitivity analysis, it is concluded that the cost of transportation fuel is most sensitive to bio-oil yield. As the NER for all three feedstocks is more than 1, it can be said that fast pyrolysis and hydroprocessing technology is energy sustainable. Finally, this pathway could be competitive with conventional transportation fuels if the revenue from the biochar can be generated.