Thermal treatment options for single-use, multilayered and composite waste plastics in Africa

This review highlights the current level of waste plastics valorization through thermal treatment and its potential for African countries. Improved thermal treatment options are needed to convert the over 40% of mismanaged waste plastics in Africa to generate electrical and chemical energy. The values of measured and calculated energy yields from high-quality data are compared for treatment options such as pyrolysis, gasification, incineration, catalytic and plasma gasification. The investigation revealed that, for chemical energy production, catalytic gasification offers the best valuable product yield for single-use plastics with a promising liquid output of up to 80% with a low heating value (LHV) of 44 MJ/kg, gas output 6-7% with heating value of 48 MJ/m3, and solid output of 10-20%. The liquid and gas products obtained at this quality could be used as fuel in a conventional gas/diesel engine for electricity generation. For the treatment of multi-layered and composite waste plastics, plasma gasification offers the best energy recovery approach with a potential of producing syngas with LHV of 10.8 MJ/m3 and consisting of H2 and CO weight fraction of 62.5% and 34%, respectively. The feasible waste plastics treatment options are presented based on waste plastics profiles in selected regions of Africa.