Energy Potential of Natural, Synthetic Polymers and Waste Materials - A Review

Abstract

In this paper, the energy potential of natural (polysaccharides, lignin, etc.), and synthetic polymers (polyolefins, etc.), polymer materials (plant biomass, plastics and their solid waste), as well as combustible liquids and gases derived from them has been studied. To determine calorific values of solid, liquid and gaseous substances, various experimental and calculation methods were used. For this purpose, improved equations based on chemical structure and elemental analysis was proposed. It was shown that the conversion of solid materials into liquids or gases reduces the yield of thermal energy. Therefore for the production of thermal energy, it is more profitable to burn the solid biomass or plastic than combustible liquids and gases, derived from them. Studies have shown that lipids and lignin increase, whereas moisture and ash reduce the calorific value of biomass. The calorific value of most synthetic polymers and plastics is higher than that of biomass samples, but resources of waste plastics are about 10 times lower than these of biomass. The use of compacted mixture of biomass and plastic waste enables to obtain solid fuels with unique properties, such as increased calorific value and energy density, as well as reduced emission of carbon dioxide. Considering the total amount of biomass and plastics waste destined for combustion, it was calculated that current annual energy potential of the waste materials is about 145 EJ. The increase the share of biomass in the production of alternative energy can simultaneously contribute to reducing in greenhouse gas emission and improving the ecological state of the environment. Keywords: Plant polymers; Biomass; Synthetic polymers; Plastics; Solid waste; Solid fuel; Liquid fuel; Gaseous fuel; Calorific value; Energy density; Energetic potential