Integrated bagasse utilization system based on hydrothermal liquefaction in sugarcane mills: theoretical approach compared with present practices

Abstract

Sugarcane bagasse is used to produce bioenergy in sugar mills and export excess energy as electricity to the community. Researchers have investigated the production of high-energy bio-oil and hydrochar from bagasse using hydrothermal liquefaction (HTL) on a laboratory scale. However, the energy efficiency of the HTL integrated bagasse utilization system at the industrial level is unknown, especially compared with present practices of baggage utilization. Therefore, the objective of this study was to analyze the theoretical energy utilization of an HTL integrated bagasse utilization system compared with conventional bagasse utilization systems. A new bagasse utilization system was modeled and combined with HTL. We used data from published articles and experiments to analyze the model. We simulated the model with different bio-oil and hydrochar yields and four levels of heat recovery from the HTL final products. The results show that the novel process could exceed electricity export rate compared with the conventional system, with high bio-oil and hydrochar yield at 23% heat recovery level. Further results show that the HTL integrated system with high bio-oil and hydrochar yields and 75% heat recovery presented an electricity export benefit, which was above 170% higher than that of the existing method in ideal conditions when using high-moisture bagasse. Finally, further research should develop high-efficiency heat recovery systems, environmentally friendly HTL product separation techniques, and direct combustion of bio-oil and hydrochar to realize this concept for improving the energy utilization of sugarcane mills.