Energy and exergy analyses, and elemental distribution of microwave-assisted auger pyrolysis of textile dyeing sludge and furfural residue

Abstract

Microwave-assisted pyrolysis has emerged as a promising treatment method for textile dyeing sludge (DS) and furfural residue (FR), demonstrating the potential to address environmental issues and harness their energy. In this study, microwave-assisted auger pyrolysis of DS and FR was conducted, and the mass balance, elements distribution, energy, exergy and sustainability analysis were investigated. The results indicated that the distribution ratios of carbon (46.14–76.29%), hydrogen (15.04–47.96%), and oxygen (3.62–36.55%) in chars decreased with increasing temperature. As the pyrolysis temperature increased during FR pyrolysis, there was a higher thermal energy loss and a decrease in energy efficiency, energy yield, and exergy efficiency. The pyrolysis temperature and the type of solid wastes are key factors in determining both energy efficiency and exergy efficiency. The energy/exergy utilization efficiencies for FR pyrolysis (57.03–82.24%/55.90–81.82%) surpassed those for DS pyrolysis (26.46–38.93%/23.35–36.65%). The highest energy and exergy efficiencies for DS (i.e. 38.93% and 36.65%) and FR (i.e. 82.24% and 81.82%) were achieved at 450 °C. FR pyrolysis had a lower environmental impact than DS pyrolysis. This study aimed to provide insights into the treatment and disposal of sludge and FR through microwave pyrolysis, considering both energy and exergy aspects.