Maximizing Waste-to-Energy Potential: Optimizing Batch Torrefaction Reactor of Refuse-Derived Fuel for Efficient Gasification

Abstract

Refuse-derived fuel (RDF) from municipal solid waste is a promising alternative to fossil fuels, but its varied composition can impede direct gasification. This industrial research project conducted a series of batch experiments to assess four key parameters: energy yield, mass yield, energy density, and combustion characteristics in the context of RDF torrefaction. The batch reactor processed RDF samples at temperatures of 250 °C, 300 °C, and 350 °C, each with a 30-minute residence time under an inert atmosphere. In addition, combustion thermogravimetric analysis experiments, involving heating torrefied RDF up to 1000 °C at a rate of 20 °C/min, provided further insights into the robust combustion properties of the torrefied material. Unlocking the secrets of torrefaction magic, we've achieved remarkable energy content boosts. Torrefaction at 250 °C, 300 °C, and 350 °C led to energy content enhancements of 22%, 29%, and 37%, respectively, compared to the original RDF. Notably, the most favorable energy yield was achieved during torrefaction at 250 °C, attributed to both its relatively high energy content and mass yield. At a torrefaction temperature of 250 °C and above, the torrefied RDF samples exhibited heating values comparable to standard coal ranges between 25 MJ/kg and 35 MJ/kg. It is suggested that torrefaction of RDF is an effective pre-treatment process to be used in entrained flow gasifier due to the improved higher heating value, higher energy density, and superior combustion characteristics, proved by the ignition index, flammability index, and burnout index, highlight the effectiveness of the torrefaction process.