Decarbonization by Energy Recovery from Waste Plastics in Cement Industry

Abstract

The cement industry utilizes many wastes and by-products. In particular, the utilization of waste plastics in cement manufacturing processes is a method that can properly treat them while making effective use of their thermal energy. The use of waste plastics, which are conventionally incinerated due to the mixing of inorganic components or multiple resins, as a substitute for coal for high-temperature firing cement clinker is considered to have a decarbonizing effect. This paper introduces a case study where CO₂ emission reductions by energy recovery from waste plastics in the cement manufacturing process were calculated based on LCA methods. The results of the calculations using an actual plant as a model showed that replacing 32% of the required thermal energy with waste plastics could reduce CO₂ emissions by 75 kg per ton of cement, equivalent to about 10% of the emissions intensity of the entire cement manufacturing process. It is expected that a technology will be developed to allow more waste plastics to be used in the cement manufacturing process, and that this will be utilized as one of the treatment methods of waste plastics which have become an international issue.