The Study Of Reagent Chemistry In Oily Sludge Washing Process

For the purpose of oily sludge detergency and recovery of oil content using chemical heat washing process, the research chooses oily sludge and analyses the ingredient of them by standard griddle, microgram measurement etc. Then according to the result we choose the proper process of oily sludge treatment.Using the residual oil percentage of treated sludge, the study investigates the influence factors including agitate temperature, agitate time, pH, agitate intensity, solid-liquid ratio, reagent concentration etc. on the efficiency of oily sludge washing and conducts to optimize the process parameters. In these optimize parameters we selected surfactant from 11 chemistry doses. By a mixture surfactant from above selected surfactants, a serious of experiments were conducted to determine the optimal ratio of each component. Then we did optimize parameter experiment to Na₂SiO₃ which dominates the washing efficiency of mixture surfactant.(1)According to the analyses of ingredient, the oily sludge used in the experiment contain a lot of solid. And the main granule size is 0.125-0.250mm. Oil concentration is 17.5%. The most ingredient of the oil in the oily sludge is extractable oil. There is little water in the oily sludge. According to the oven drying experiment, the burned oil is the most in 350-500℃. Based on the ingredient of oily sludge we chose the hot water washing process as the process of oily sludge treatment.(2)The oily sludge washing experiment indicated that the optimal efficiency of oily sludge washing was achieved when agitate temperature was at 70℃, agitate time 30min, agitate intensity 36.3s^-1, pH=9 and solid liquid ratio 1:5.(3)The washing effect of anion surfactant AEO-9, NP-10 and dispersant Na₂SiO₃ was better than others. By using above chemistry dose the oil concentration in treated sludge would less than 2%.(4) By a mixture surfactant from above three components, a serious of experiments were conducted to determine the optimal ratio of each component, and results supported two surfactant dispensing (1)3 (AEO-9) : 1 (NP-10) : 6 (Na₂SiO₃); (2)1 (AEO-9) : 3 (NP-10) : 6 (Na₂SiO₃). Under this condition, the residual oil percentage of treated oily sludge may be less than 0.3%. And the Na₂SiO₃ dominates the washing efficiency of mixture surfactant.