Role of Downdraft Gasifier of Torrefied Refuse Derived Fuel Blended With Charcoal for Green Electricity Production

Landfill and open dumps of municipal solid waste (MSW) have been considered as the conventional practice for disposal, but are not the ultimate solution regarding the impact on the environment and health. Closed landfills need to be reclaimed and used for another purpose, but the waste left after reclamation can also be used as the source of green and renewable energy in the form of refuse derived fuel (RDF). Gasification has been proven as the intermediate step to recover energy from reclaimed RDF, but with the high fraction of high-density polyethylene (HDPE) inside, it needs to be blended with a suitable material in order to increase the fixed carbon fraction prior to being used in gasification. In this study, HDPE from recycling plants was used as a surrogate RDF from reclaimed landfill, then was upgraded through the torrefaction process before being mixed with paper and charcoal and used as feedstock in a 30 kg/h batch-type downdraft gasifier. The producer gas obtained from the gasification process was partially used as a replacement to diesel fuel in a modified dual engine that was coupled with a 15-kW generator to generate clean and green electricity. The experimental results were reported in terms of the effect of torrefaction of RDF and the effect of air ratio on feedstock consumption rate, diesel replacement rate, and overall efficiency.