Cost estimate for biosynfuel production via biosyncrude gasification



Production of synthetic fuels from lignocellulose like wood or straw involves complex technology. There-fore, a large BTL (biomass to liquid) plant for biosynfuel production is more economic than many small facilities. A reasonable BTL-plant capacity is ≥1 Mt/a biosynfuel similar to the already existing commercial CTL and GTL (coal to liquid, gas to liquid) plants of SASOL and SHELL, corresponding to at least 10% of the capacity of a modern oil refinery. BTL-plant cost estimates are therefore based on reported experience with CTL and GTL plants. Direct supply of large BTL plants with low bulk density biomass by trucks is limited by high transport costs and intolerable local traffic density. Biomass densification by liquefaction in a fast pyrolysis process generates a compact bioslurry or biopaste, also denoted as biosyncrude as produced by the bioliq® process. The densified biosyncrude intermediate can now be cheaply transported from many local facilities in silo wagons by electric rail over long distances to a large and more economic central biosynfuel plant. In addition to the capital expenditure (capex) for the large and complex central biosynfuel plant, a comparable investment effort is required for the construction of several dozen regional pyrolysis plants with simpler technology. Investment costs estimated for fast pyrolysis plants reported in the literature have been complemented by own studies for plants with ca. 100 MWth biomass input. The breakdown of BTL synfuel manufacturing costs of ca. 1 € /kg in central EU shows that about half of the costs are caused by the biofeedstock, including transport. This helps to generate new income for farmers. The other half is caused by technical costs, which are about proportional to the total capital investment (TCI) for the pyrolysis and biosynfuel production plants. Labor is a minor contribution in the relatively large facilities. © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd