Design and optimization of solar-assisted conveyer-belt dryer for biomass

Biomass, as a renewable source of energy, can be used in many industries to reduce their dependence on fossil fuels. However, due to the significantly high and varied moisture content of biomass, its use has several drawbacks, such as low total efficiency and process instability. Drying biomass before combustion or gasification can eliminate these drawbacks. Besides these benefits, there are several environmental advantages of removing moisture from organic materials before disposal. In this study, a solar-assisted conveyer-belt dryer was designed to remove moisture from biomass. Economic optimization was conducted under different economic conditions to find the optimum performance of the designed dryer. The results indicated that depending on the economic condition, drying biomass with the designed dryer costs between 4 and 7 cents per kilogram of biomass. Under optimum economic operation, the solar fraction is less than 6% in both scenarios. On the other hand, by ignoring economic constraints and reducing the dryer’s capacity, solar fraction increases to more than 55%, and in this case, the drying cost will be about 11 cents per kilogram of biomass.