Torrefaction of Food Waste in Vietnam for Using It as an Alternative Energy Source

Abstract

In developing countries like Vietnam, there are not many methods for food waste reprocessing. Although food waste accounts for 40% of municipal solid waste, the energy potential of the former is very low in view of a high moisture content, and most of food waste is disposed in landfills. Food waste is the main cause of water and air pollution problems around landfills, and they have a very negative effect of the environmental conditions of cities. To reduce the burden on the environment, various food waste processing methods are developed and investigated, which is a matter of concern in many developing countries. However, in view of such characteristics of food waste as high moisture content (up to 70%) and low heating value (less than 4.6 MJ/kg), the use of a number of methods for processing it is difficult. To overcome these difficulties, the torrefaction method can be used as a pretreatment measure to improve the food waste characteristics. A data collection method and an experimental method involving the use of a high-temperature furnace to study the influence of temperature in the range from 225 to 300 °C on the torrefaction process have been implemented. The study results have shown that the torrefaction product’s higher heating value increases with increasing the temperature from 225 to 300 °C, while the energy yield decreases by almost 16%. The product’s highest heating value obtained at 300 °C is 26.41 MJ/kg, which is equivalent to the heating value of coal. This shows that torrefied food waste can potentially be used as an alternative fuel source in the future. The obtained results will be applied in the research and development of methods for torrefying not only food waste, but also other types of organic waste with a high moisture content and in the development of thermal process schemes for producing fuels from energy-carrying waste.