Thermogravimetric analysis and kinetics of the combustion of refining and chemicals wastewater in different oxygen concentrations

The oxygen-enriched air combustion behaviors and kinetics of refining and chemicals wastewater (RCW) solid were investigated using thermogravimetric analysis. The results showed that the combustion process of RCW solid was a four-stage reaction. The increase in O-2 concentration had negligible effects on the overall first two stages and the vast majority of the third stage, while made the fourth stage shift to a lower temperature region. The kinetic triplets of each stage were determined by Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, and the master-plots method. For the first three stages, the average E of each stage varied slightly with of O-2 concentration increasing; while the fourth stage showed a rising trend. The most probable reaction models for the first and second stage were the simple order reaction model (F-n), while the random nucleation and nuclei growth model (A(n)) for the third and fourth stage.