Enhancement of petroleum coke thermal reactivity using Oxy‐cracking technique

Comprehensive Estimation of Combustion Behavior and Thermochemical Structure Evolution of Four Typical Industrial Polymeric Wastes

A huge amount of industrial waste will be generated during the industrialization process and their harmless disposal has always been a headache for reducing carbon emissions. In this study, the combustion behaviors and thermal kinetics of four typical industrial polymeric wastes including rubber, leather, plastic and cloth, were systematically studied by using a Thermogravimetric Analysis. The gas emission and structural evolution was comprehensively analyzed using TG-FTIR, 2D-PCIS, ICP and TEM. The results show that the combustibility of leather and cloth are better than the other two samples, while the rubber and plastic have a wider combustion temperature range for higher content of C-H bonds and, the intermediate oxidation process and the stubborn cracking process of C=C bonds. The surface reaction was considered to be the main reaction of rubber and plastic (pre-exponential factor less than 10−9), while both leather and cloth went through a complex procedure during multiple decomposition. The volatiles products are gases (e.g., CO2, CH4) and small molecules (e.g., H2O). The high levels of basic metals in the industrial waste causes serious slagging and fouling tendency (fouling index higher than 4.0), which have a serious adverse influence on the operation of a waste incineration plant.

Wet Air Oxidation of Oil Shales: Kerogen Dissolution and Dicarboxylic Acid Formation

Until now, the oil shale kukersite has been used mainly for energy and oil production. To broaden the possible applications of oil shales, the wet air oxidation of kukersite (an organic-rich sedimentary rock from Estonia) was studied. Kukersite was oxidized with an oxygen-rich gas in water at temperatures up to 200 °C and pressures up to 60 bar. The efficiency of this batch process was evaluated from organic matter conversion, from the amount of solubilized organics obtained, and from the rate of dicarboxylic acid (DCA) formation. The effect of several reaction parameters-pressure, temperature, time, acid/base additives, substrate concentration, the origin of a substrate and its organic matter content, and so forth-was measured. A conversion of 91% in total organic carbon was achieved at 175 °C with 40 bar of the 1:1 oxygen/nitrogen mixture in 3 h without the presence of any additives. Under basic conditions, high yields (up to 50%) of dissolved organic matter were obtained with 8% of DCA; the best results are obtained with K₂CO₃ and KOH. The highest DCA outcome (12%) within the 3 h reaction time was obtained in the presence of acetic acid. It was found that temperatures higher than 185 °C, pressures over 30 bar of pO₂, and long reaction times in the acidic media caused a considerable decrease in the DCA outcome. It was also found that the same process can be applied to shales of different origins, although with lower DCA yields.