Solar pyrolysis of carbonaceous feedstocks: A review

Solar pyrolysis of a carbonaceous feedstock (coal, biomass and wastes) is a process in which carbon-containing feedstocks are used as chemical reactants and solar energy is supplied as high-temperature process heat. This process has the potential to produce higher calorific value products with lower CO2 emissions than conventional pyrolysis processes. As a consequence, the intermittent solar energy is chemically stored in the form of solar fuels. Solar pyrolysis was first demonstrated in an indoor environment using a solar simulator (image furnace) for exploring the fundamental mechanisms of carbonaceous feedstock pyrolysis under severe radiative conditions (high temperatures and heating rates) in comparison to conventional pyrolysis. More recently, low-temperature solar pyrolysis has been demonstrated to be a good technology for bio-oil production. Our high-temperature solar pyrolysis process produces more combustible gas products than other processes. This paper reviews developments in the field of solar pyrolysis processing by considering fundamental mechanisms, experimental demonstrations, models and challenges.