Hydrothermal Torrefaction of High Moisture Content Biomass

There is a lot of potential for biofuel and bioenergy production from forests and agriculture residues. However, delivery cost of biomass to a conversion facility is high and have distinct economic and technological challenges.

Today, commercial-scale bio-based energy facilities are at capacities significantly below those of current fossil-fuel based plants. This is mainly due to the high cost of transporting feedstock by truck to the plants. Truck delivery of wet biomass (e.g., wood chips, agricultural residue) to commercial conversion plants is not economically reasonable and logistically challenging. Pipeline transport of forest biomass in the form of slurry (a wood chip-water mixture), on the other hand, provides an alternative approach that enables bio-based energy facilities achieve higher capacities, since pipeline delivery receives benefits through economies of scale. Forest biomass slurry would enter the facility directly with or without minor adjustments in the biomass-water ratio. Pipeline transport of biomass can significantly reduce the cost of transportation of biomass.

This research directly aligns with the challenges of transporting biomass over vast distances. The transported biomass could be used for production of fuels and energy. Biomass transported through pipeline in the form of a slurry with water would have high moisture content. However, integrating pipeline delivery with efficient hydrothermal (HT) biomass processing technologies could transform the bioeconomy. HT processes uses biomass in the form of a slurry and produces liquid fuel/gas/solids which can be used for production of fuels and energy. HT processing is a state-of-the-art thermochemical conversion using biomass feedstock with high moisture content (60-80%) especially in slurry form. This conversion process converts biomass into useful solid product with high calorific value and very low moisture content which can be for producing fuels and electricity. This integration of technologies can help in producing biofuel and power at significantly lower cost. There is no penalty in transporting biomass as a solid-liquid mixture for biofuel production purposes via HT (torrefaction, liquefaction, gasification), where the process itself is aqueous.

This project is aimed at developing a transformative solution through integration of the pipeline transport of biomass with HT processing technologies. Pipeline transport helps in reducing the transportation cost compared to truck and rails and HT technologies help in processing biomass with high moisture content. Hence marrying these two technologies could be transformative and help in solving key challenges in development of a bioeconomy in Canada. One of the most modest treatments is hydro-torrefaction at temperatures of 150-200C. The hydro-torrefied biomass has decreased hydrophilicity, increased calorific value and reduced ash content. It is easier to remove water from the hydro-torrified biomass. Hydrothermal carbonization converts biomass into hydro-char with high concentration of oxygenated functional groups important for sorbents or catalysts.