Polyaluminum chloride and polyacrylamide for oilfield sewage treatment Oilfield wastewater contains a large number of easily corroded pipeline, suspended particles and crude oil, the experiment is mainly the physical treatment of sewage, the main process of regulation, grease, flotation, Settlement, filtration, water. After the flotation, the settlement need to use coagulant PAC and coagulant polyacrylamide in the sedimentation of impurities and suspended solids after filtration to remove water. The specific experiments are described as follows: 1. Experiment 1. Experimental Principle Corrosion behavior of sulfide ion content on N80-type coupon at 50 degrees in the oilfield field conditions is simulated and the corrosion rate is calculated. Then by electrochemical method [4] so that chloride ions in the simulated water samples were oxidized to chlorine gas, chlorine in the solution to generate hypochlorite, control the electrolysis time so that sulfur ions and hypochlorite to generate sulfur elemental. Add flocculant polyaluminium chloride precipitation elemental sulfur, after half an hour through the measured minimum turbidity value and the optimal pH to select the appropriate dosing amount, stirring rate and time. 1,2 experimental apparatus N80-type coupons; WYL1702. 2 dual DC steady current power supply; METTLER TOLEDO DELTA 320 acidity meter; Italy Hannah Instruments LP2000- 11 photoelectric turbidity meter. 1.3 Experimental methods 1.3.1. Simulation of water samples According to the analysis of the water quality components of Jiang Yan'an Oilfield, the laboratory prepares simulated water samples. 1.3.3 Sulfur production by PAC removal According to the concentration of sulfide ions (65 ~ 80mg / L), 1L simulated water samples were added 0.5250g sodium sulfide (sulfur ion concentration of 70mg / L), electroporation 7.5min (current density 0.05A / cm2, plate spacing 3cm), chloride ions in the anode Oxidation to chlorine gas, chlorine in aqueous solution to generate hypochlorous acid hydrolysis, hypochlorite and sulfur ions react to form sulfur elemental. The 1 L after electrolysis solution is divided into 5 parts, respectively 0.2,0.5,0.8,1.1,1.4 g / L added flocculant PAC. Electromagnetic heating stirrer first 300r / min stirring speed stirring 1min, and then stirred at a selected stirring rate, standing for half an hour to take 2 ~ 3cm supernatant to measure the pH and turbidity, according to the optimum turbidity using Electrochemical oxidation of sulfur in oilfield wastewater is sulfur, aluminum polychloride for oilfield wastewater treatment desulfurization. The effects of flocculant dosage, stirring intensity and stirring time on the desulfurization efficiency of flocculants were investigated. The results showed that when the mass concentration of PAC was 0.8g / L, the stirring rate was 100r / min and the stirring time was 4min, flocculation The best effect, the water turbidity minimum, pH close to neutral