Process Simulation of Preparing Biochar by Biomass Pyrolysis Via Aspen Plus and Its Economic Evaluation

PurposeChina is a big agricultural country and generates a large amount of biomass wastes every year. Biomass is the only renewable carbon source, which can produce biochar through pyrolysis under anaerobic or hypoxic conditions. Biochar has a rich pore structure, large specific surface area and special adsorption properties, and has been widely used in different industries. Different raw materials and pyrolysis conditions influence its yield and pore structure.MethodsIn our study, a flow chart was established in Aspen Plus V8.4 software to simulate the pyrolysis process of rice straw and sugarcane bagasse, and the feasibility of the model was verified by experiment. Finally, the Life Cycle Cost (LCC) method was used to evaluate the economics of the process of preparing biochar from 1 t rice straw and sugarcane bagasse.ResultsThe simulated value of biochar yield is different from the experimental value. The difference is small at low temperature (300–500 °C), and relatively large at high temperature (600–800 °C), but both remain between 0.55 and 8.93%. Calculations indicate that the costs of rice straw and sugarcane bagasse biochar were 0.79 and 0.93 USD/kg, respectively.ConclusionConsidering from the aspects of yield, pore structure, energy consumption, and economy of biochar, compared with sugarcane bagasse, rice straw has a more competitive advantage in the preparation of biochar.Graphical Abstract