Thermal behavior and gas products of cold rolling oily sludge by TG-MS and Py-EGA/MS
Yinxuan Fu, Zhigang Que, Jinming Shi, Xianbin Ai, Wu Zou
Abstract
Cold rolling oily sludge contains a series of mixtures such as high content of iron and organic residues. The evolution law of volatile components of cold rolling oily sludge during thermal treatment was studied through pyrolytic and kinetic analysis. The effect of heating rate on cold rolling oily sludge was studied by TG. According to the results of mass loss, it divided to two stages: 100 °C–600 °C and 600 °C–1000 °C. The pyrolysis kinetics were investigated by three kinetic models: KAS, FWO, and DEAM. By analyzing the models, it was found that the increasing value of Ea was accompanied by a progressive increase in conversion rate between 100 °C and 600 °C and the average of Ea, ΔH, ΔG and ΔS value were also calculated as 163.26 kJ⋅ mol−1, 157.45 kJ⋅ mol−1, 194.67 kJ⋅ mol−1, -67.41J⋅ (mol⋅ T)−1 respectively. When the temperature was above 600 °C, it was hard to acquire the active energy owing to synergistic effect of redox reaction and pyrolysis reaction. Combining TG-MS and Py-EGA/MS, it seemed that the gas escaping trace had the similar trend. There were H2, CH4, CO, CO2 found in gaseous products. Carbon dioxide and carbon oxide were the main gas products above 600 °C.