Energy Sources Part A-recovery Utilization and Environmental Effects, Vol.38, No.9, 1219-1235, 2016
Key techniques and parameters for briquetting corn stover sprayed with biogas slurry in a cold region in China
Densification of biomass is often necessary to combat the negative storage and handling characteristics of these low-bulk-density materials. Corn stover is an important feedstock being considered for production of renewable fuels and energy in China. Densification of corn stover would help reduce the problems and costs of bulk transportation, handling, and storage of biomass feedstock. In cold regions, some thermosetting binder will be added when briquette fuel is made with corn stover because of its high water and lignin content. It is important to understand the synthesis mechanism of thermosetting binder under certain temperature and pressure combined with strong alkaline slurry to explore develop ment of a new process of briquetting corn stover based on only alkaline slurry as an environment-friendly binder. In this study, flat-die briquetting machine has been used with a cone-shaped press roller, and a matching die hole on the press plate. At the same time, orthogonal experiments were designed from the results of single-factor experiments to obtain optimal briquetting conditions. The effects of spray quantity of biogas-slurry, size of die hole, and water content of corn stover on the durability and bulk density of corn stover briquettes were investigated. Moreover, the model for whole factors and the model for interaction between factors for indexes have been built, emulated the optimum processing parameters. The results show briquettes of corn stover with durability of 83.33% were produced when the spray liquid flow quantity of biogas-slurry, size of die hole, and water content of corn stover were 0.45 L/kg, 28 mm, and 20%, respectively. Bulk density of 616 kg/m(3) was produced when the spray liquid flow quantity of biogas-slurry, size of die hole, and water content of corn stover were 0.3 L/kg, 24 mm, and 25%, respectively. These results have been checked by verification testing. The successful implementation of this project provides theoretical support and test instruction for the development of green biomass energy for sustainable development.