A Study On The Characteristics Of Catalytic Ozonation Of Oil Fracturing Wastewater

With the development of oil industry, environmental risks of oil waste water and the potential health and safety risks brought thereby have gradually drawn increasing attention. Therefore, handling of oil waste water effectively has great significance on solving the environmental problems caused in the process of oil and gas field development. In this paper, degradation characteristics of oil fracturing wastewater using the two Advanced Oxidation method of ozonation and catalytic ozonation was discussed with analysis methods such as HPLC, FT-IR, GC-MS and so on. This would provide a theoretical basis for the future advanced oxidation technologies and the practical operation.In this study, the raw water used was water-based fracturing fluid. The molecular weight distribution of oil fracturing wastewater, the main functional groups and chemical structure was analyzed using analysis methods such as High-Performance Liquid Chromatography (HPLC), Fourier Transform Infrared Spectroscopy (FT-IR), Gas Chromatography and Mass Spectrometry (GC-MS) and so on. Results showed that the apparent molecular weight of the raw fracturing wasterwater was mainly in the context of 200-2000Dalton, organic matter with molecular weight content 1000-2000Dalton was in the majority; the main functional groups were benzene, esters, hydroxyl, carboxyl, carbonyl, amino, etc; organic matter in raw fracturing wasterwater was mainly aromatic compounds in benzene ring and organic matter composed of other heterocyclic structures, the main functional groups on benzene and heterocyclic included ketones, esters, carboxylic acids, aldehydes, phenol, amino and so on. The results show that, the oxidation characteristics were similar whether it was alone ozone oxidation fracturing wastewater or catalytic ozonation fracturing wastewater. All of them could make the macromolecular organic waste into small molecule organic compounds. Number and types of ring like organic pollutants in the wastewater gradually reduced with the oxidation time increasing, which indicated that at first oxidation reaction was gradually breaking the unsaturated ring pollutants, and then broken down rings by degrees, then the hydrocarbons with small molecules such as esters, acids, phenols, alcohols, straight-chain alkanes and so on formed and ultimately thoroughly carbonized. Difference between the two kinds of oxidation was organic matter degradation efficiency of catalytic ozonation was higher than single ozonation, and HPLC detection results of hydroxyl radical showed that production of hydroxyl radicals in the catalytic ozonation process was significantly higher than ozonation; COD removal rate of final ozone oxidation fracturing wastewater was 43%, while the COD removal rate of catalytic ozonation fracturing wastewater was 63.3%.