The invention relates to a thermal
conversion method and a thermal conversion device of
solid fuel, wherein the thermal conversion of the
solid fuel is composed of three independent and association-controllable sub-processes of
pyrolysis, gasification and burning by decoupling the integrated
pyrolysis, gasification and burning reactions in the conventional thermal conversion process. A hot carrier substance is circulated among the sub-processes, so that the burning sub-process provides reactive heat to the
pyrolysis and the gasification sub-processes and simultaneously provides
oxygen to the gasification process to initiate internal burning so as to compensate for the gasification reaction heat that the hot carrier substance is unlikely to supply. Accordingly, the thermal
conversion method can control the three thermochemical reactions of pyrolysis, gasification and burning by decoupling, recombination and association to achieve combined production of
pyrolysis oil, synthesis gas and heat. Different from conventional single conversion devices for burning, gasification and pyrolysis, the thermal
conversion method of the invention has the advantages of compact structure,
high heat utilization efficiency and greatly reduced
oxygen consumption for synthesis gas production, thus achieving high-value comprehensive conversion and utilization of
solid fuels such as
brown coal,
bituminous coal and
biomass.