Co-thermal Degradation Characteristics of Rice Straw and Sewage Sludge 

Abstract

This study investigates the kinetic behaviors and gas evolution of rice straw, sewage sludge, and their blends under co-thermal decomposition processes using Thermogravimetric analysis combined with Fourier-Transform Infrared Spectroscopy (TGA-FTIR). The experimental results indicate that sewage sludge could be enhanced the volatile matter decomposition in rice straw co-thermal process at lower temperatures. Activation energy decreases from 53.07 kJ/mol to 48.62 kJ/mol with an increase in sewage sludge addition from 50% to 80% under pyrolysis conditions. The major volatile components were aliphatic chains with double bonds, as well as carbonyl, hydroxyl, and C–H groups in organic compounds by FTIR identification. The tested materials characteristics in terms of volatile matter-to-fixed carbon (VM/FC) ratio was significantly affected the thermal degradation performance. Activation energy was decreased with increasing the VM/FC ratio. It implied that co-thermal reaction could be accelerated. In summary, the results could provide the important information for co-thermal treatment of sewage sludge and rice straw in commercial-scale plant.