Using Pyrolysis to Convert Biomass to Biochar with Heat from on-Site Solar Thermal Energy

This project is looking to construct a solar concentrating system coupled to a biomass pyrolyzer that uses molten salts to store and transport solar thermal energy between the solar receiver and the pyrolyzer.   The project will explore the feasibility of using a distributed solar thermal biomass pyrolyzer for biomass densification.  The biomass pyrolyzer will conduct on-site biomass densification before transport that could help reduce the energy needed for biomass transport.  A prototype parabolic mirror sun concentrator and an optimized receiver were constructed, during the summer of 2015, as the starting stage of this project.  An additional manufactured parabolic mirror was purchased.  During testing, the average temperature of the handmade dish was 300ºC and the average temperature of the manufactured dish was 400ºC.  Only the manufactured dish allowed for slow pyrolysis and production of Biochar over long periods of residence time.  Biochar was pyrolyzed in batches within the confines of the receiver.  With the aim for this system to be used on a small local scale, wood, cardboard, coffee, hops, and sticks were tested.  In the future, improvement of the system's biomass capacity by introduction of a molten salt as a heat transport mechanism will be the goal.  The hope is to be able to have the biomass reactor as a separate subsystem from the concentrator and receiver to allow for modular functionality and higher optimization of the pyrolysis process than can presently be achieved.