Recent advances in the thermochemical transformation of biomass to bio-oil, biochar and syngas and its upgrading methods

Abstract

The continuous increase in energy demand due to the rapid increase in population and urbanization has increased the dependency on fossil fuels such as oil, natural gas, and coal. For instance, in 2021, the energy demand increased by 5.8 % and it is expected that the global energy requirement will rise several-fold by the year 2050. In 2021, fossil fuels accounted for ∼82 % of the global energy consumption. However, this excessive use is causing real threats to humanity and the environment, besides contributing to global warming and climate change. The global temperature has risen by 1.53 ºC since 1800, or pre-industrial times, due to the emission of greenhouse gases (GHGs) from the combustion of fossil fuels. Despite all the demands and efforts to reduce GHGs emissions, especially carbon dioxide (CO2) emissions, the global CO2 emissions hit a record high in 2021 to reach 413.2 ppmv. In addition, according to the Global Annual Temperature Outlook of the National Centers for Environmental Information (NCEI), the year 2022 will be ranked among the ten warmest years on record. Besides its harmful effect, fossil fuels are known as depletive resources; therefore, finding efficient, effective, and renewable resources to replace fossil fuels has become a compelling issue for different stakeholders.