Co-pyrolysis performances, synergistic mechanisms, and products of textile dyeing sludge and medical plastic wastes

Abstract

This study aimed to quantify the co-pyrolysis of textile dyeing sludge (TDS) and the two medical plastic wastes of syringes (SY) and medical bottles (MB) in terms of their performances, synergistic mechanisms, and products. The pyrolysis of polyolefin plastics with its high calorific value and low ash content can offset the poor mono-pyrolytic performance of TDS. The synergistic mechanisms occurred mainly in the range of 400-550 °C. The addition of 10% SY or MB achieved the best co-pyrolysis performance with the lowest activation energy. The co-pyrolysis increased the contents of CH₄ and CH but reduced CO₂ emission. The co-pyrolysis released more fatty hydrocarbons, alcohols, and cyclic hydrocarbon during but reduced the yields of ethers and furans, through the synergistic mechanisms. The addition of the polyolefin plastics made the micro surface particles of chars smaller and looser. Our results can benefit energy utilization, pollution control, and optimal operational conditions for the industrial thermochemical conversions of hazardous wastes.

Keywords: Circular economy; Polyolefin plastics; Pyrolytic oils; Sludge; Volatiles products.