Increasing the Biomethane Yield of Hazelnut By-Products by Low Temperature Thermal Pretreatment

Abstract

Biomethane energy, which has the status of renewable energies, has the potential to be produced from all kinds of organic wastes, as well as from lignocellulosic materials, which are the most common in nature. In this study, hazelnut shells (HS), one of the hazelnut by-products, were used for biomethane production. In order to obtain higher yields from HS, thermal pre-treatments were applied at temperatures of 60°C, 80°C and 100°C. Pretreatment effects were controlled by lignocellulosic substance amount determinations. As a result of thermal pretreatment at 100°C for 2 h, cellulose and lignin removals occurred approximately 15% and 30%, respectively. While the cumulative biomethane yield of raw HS was 32.3 mL•g total solids (TS)‒1, the cumulative biomethane yields of 100°C pretreated HS were measured as 132.3 mL•gTS‒1. As a result of different pretreatment temperatures, different cumulative biomethane yield curves were successfully simulated with the Modified Gompertz equation and R2 values were found to be between 0.9962 - 0.9985.