Development of microwave-assisted pyrolysis apparatus and some experiments on agricultural biomass wastes: cashew shells, bagasse, and dried algae

Agricultural wastes have huge biomass potency which can convert energy in the form of liquid fuel, solid, and syngas in one process by using the pyrolysis technique. The process can be driven to fast and flash pyrolysis to obtain yield in liquid form by using microwave heating method. This research started by developing an experimental laboratory apparatus by modifying a commercial microwave oven. It worked safely, and some experiments had been carried out. The process could run only 10–20 mins, much faster than conventional heating, which needs more than 2 hrs for pre-heating. By using chopped cashew nuts as raw material, bio-oil results were 9.33% and 25.00%. Dried algae and bagasse needed biochar as the material absorber. The experiments showed, dried algae with 0% and 10% biochar gained bio-oil yields of 3.19% and 15.00%. Feeding bagasse as raw materials with 0%, 10%, and 20% biochar, resulted in bio-oil of 42.45%, 39.10%, and 42.75%. GC/MS analysis of bio-oil identified that it contained 42.24% of non-oxygenatic compounds and 57.76% of oxygenatic compounds. This non-oxygenatic compound contains a long and stable carbon chain. These results proved that the experimental apparatus can work properly and safely.