New biomass-to-liquid process from wood chips to motor fuels

Kurzfassung

2nd generation biofuels gained more importance in recent years since they enable greenhouse gas emission reductions in the transport sector on a larger scale. One promising way to produce alternative fuels is the Biomass-to-Liquid (BtL) process with the Fischer-Tropsch synthesis which produces synthetic hydrocarbons that could directly be used as liquid fuels in an existing infrastructure. One major issue of this process is the production cost. Within the European COMSYN project (Compact Gasification and Synthesis process for Transport Fuels), a new BtL process concept is developed that aims to reduce biofuel production cost up to 35 % compared to alternative routes. The novel production concept is based on double integration benefits. The primary biomass conversion to FT product is realized in medium scale units which are heat integrated to industrial sites or district heating networks and are located close to biomass re-sources. The main product of the initial biomass conversion plants of COMSYN is liquid FT crude, solid FT-wax or hydro-treated middle distillate from various biomass sources and residue-derived feedstocks. The final conversion of FT-product to transportation fuels, primarily diesel, is realized at refinery sites, using several integration benefits and product portfolio adaptation to specific market needs (diesel, motor gasoline, kerosene components or propylene and other petrochemicals). The target capacity range of the primary conversion plant is 30 – 150 MW (feedstock input) that typically produce 10-50 kt/a FT product by 55 – 60 % energy efficiency (based on LHV). By utilizing the generated heat the total efficiency of the plant can be increased to 75 – 80 %, which is comparable to highly efficient combined heat and power production plants. To determine the feasibility of this process concept, a techno-economic assessment of the process concepts is carried out and its results are presented in this study. This includes steady-state process simulation in Aspen Plus® and standardized techno economic process evaluation for comprehensible production cost estimation. Different process options like the refinery upgrading of light diesel fraction via blending with existing hydrodesulfurization feedstock and further co-processing at hydrotreating or separate isomerization will be discussed.