Fuels from Reliable Bio-based Refinery Intermediates: BioMates

Abstract

The overall aim of the project “BioMates” is to develop a conversion process for agricultural residues (cereal straw) or energy crops (miscanthus) into a liquid intermediate with reliable properties for the co-processing in existing petroleum refineries. The process is divisible into two individual steps—ablative fast pyrolysis and mild hydrotreatment. Both biomass feedstocks were pyrolysed in a laboratory plant and optimal parameters leading to highest organic liquid yield were determined to be 540 °C at the hot surface, 50 bar hydraulic pressure and 80 rpm of rotational speed of the ablation plate. Different setups for condensation and catalytic vapour upgrade were tested and best results regarding highest organic yield with lowest water content could be achieved with a two-stage condensation operating at about 68 °C condensation temperature in the first stage. Here, a total yield of 41 wt% in (oxygenated) organic compounds could be achieved in the first stage condensate compared to only 36 wt% in the tarry phase of single stage condensation. Catalysts for direct upgrading of vapours were tested but found to be inappropriate in the current setup. For mild hydrotreatment conventional sulphidized catalyst and newly developed non-sulphidized catalysts were tested. The new catalysts showed high initial reactivity but fast deactivation. Currently, the commercial catalyst with NiMo-system on Al2O3-support performed best, especially at 8 MPa hydrogen supply pressure and 360 °C operating temperature. Here, water content below 1 wt%, a density of organic product below 0.9 kg dm−3 and a lower heating value above 39 MJ kg−1 was achieved. Electrochemical compression and purification can supply hydrogen at necessary pressure and flow rate with acceptable energy demand and by that can replace mechanical compression on the supply side and pressure swing adsorption system in the recycle loop. The project aims were fully achieved in TRL3-4 and will be demonstrated in TRL5 until the end of the project.