Study On Improving The Deoiling Effect Of Water Washing Treatment With Carbon Dioxide Injection

A large amount of oily sludge is being produced in the process of crude oil extraction and transportation.The complex chemical composition of the sludge causes serious damages to the environment and threatens the health of animals,plants and human beings without proper treatment.This thesis developed a new technology for treating oily sludge--water washing treatment with carbon dioxide injection.CO₂ extraction technology was combined with hot water washing treatment to separate oil and mud under a mid-temperature and a low-pressure.Free-reagent was added to the technology,so the CO₂ and water used could all be recycled.It broke the severe operating conditions and guided the development of oily sludge treatment process.The main research contents includes:(1)The visualized sapphire vessel was used to observe the process of treating oily sludge by water washing treatment with carbon dioxide injection.It was found that the compound deoiling effect of CO₂and water on oily sludge was much better than that of hot water washing alone.The effects of temperature,pressure,liquid-solid ratio,time and type of gas on oil cleaning were investigated by using a simple high-pressure reactor.It was found that the best result was obtained under the conditions of reaction temperature of 70?,CO₂ pressure of 4 MPa,proportion of water to oil sludge of 6:1and reaction time of 1 h and the residual oil rate decreased from 29.46%to 8.38%.(2)In order to improve the effect of oil recovery,water washing treatment with carbon dioxide injection was studied with temperature,pressure,liquid-solid ratio and time on several washing.The residual oil rate decreased to 6.06%after the second time deoiling,and the oil from the pores of the sludge removal was more thorough.Compared with available literatures,the results show that the oil recovery effect of this method is better than that of hot washing adding Na₂SiO₃?Na OH?SDBS?BS-12 or other additives.Furthermore,the chemical reagents bring secondary pollution to the subsequent treatment,so the superiorities of this method are highlighted.(3)The ultrasonic assisted water washing treatment with carbon dioxide injection was studied and the effects of temperature,pressure,liquid-solid ratio,time and ultrasonic power were investigated.The obtained deoiling result was only 4.71%under the optimum condition.The optimum operating temperature has been decreased to 30?by the synergistic reaction which makes the conditions more easy to apply,and provides a new idea for the future study of industrial deoiling.