Influence of clay metal minerals on the products of microwave pyrolysis of oil sludge

Oil sludge is a solid organic waste generated during the extraction and transport of petroleum resources. In this paper, initially, the types of oil sludge and the potential hazards of oil sludge are discussed. On this basis, the disposal process of microwave pyrolysis of oil sludge for generating three-phase products (gas, light oil, and residual carbon) for recycling is put forward, through which the oil sludge is recycled and reused, and the pollution to the environment is decreased. To elevate the reaction rate of microwave pyrolysis of oil sludge and raise the yields of gas and liquid oil, four catalysts (montmorillonite-Ca-based, montmorillonite-Na-based, kaolinite, chlorite) were introduced to experimentally dissect the heating rate, oil production rate, and gas production rate of microwave pyrolysis. The results demonstrated that the reaction rate of microwave pyrolysis was prominently enhanced after adding the catalysts, and the contents of pyrolysis oil and pyrolysis gas also increased conspicuously. The combustible gas content in pyrolysis gas (H₂ + CH₄ + CO) increased by 17.624 wt.% (montmorillonite Na-based), 9.511 wt.% (chlorite), 12.28 wt.% (kaolinite), and 15.164 wt.% (montmorillonite Ca-based), respectively, compared to that of the blank group. The clay–metal mineral catalysts, particularly montmorillonite Na-based, facilitated the sludge decomposition, augmented the content of low-carbon number straight-chain hydrocarbons and alcohols, and improved the quality of pyrolysis oil products.