Thermal conversion of biomass–pyrolysis and hydrotreating
Conversion of lignocellulosic biomass into renewable fuels and chemicals by thermal processes, especially pyrolysis, receives great attention. The products may serve as feedstock for chemicals and fuels and contribute to creation of a sustainable society. However, although progress is made in producing products selectively by pyrolysis, the application of the liquid produced by pyrolysis, often referred to as bio-oil, is limited by the physical properties of the bio-oil itself. Subsequent hydrotreating is a promising route to improve the quality of bio-oil, and this technology has rapidly progressed in the last several years. In this work, state-of-art production of bio-oil and subsequent hydrotreating will be reviewed and discussed. Moreover, further research directions will be identified.