Oily Sludge Treatment Technology Was Studied

Oily sludge, solid waste come from the oil field development, oil storage and oil refining process, is difficult to deal with for its special nature. The treatment of oily sludge is a tough problem troubled oil industry and environmental protection fields. At the present time, a majority of oily sludge was gathered waiting for effectively treatment except the part of high oil content oily sludge land filled subsequent to initially oil recovery.In this paper, study focuses on treating oily sludge from the tank bottom of Yanchang oil-fiield which has high oil volume and recovery value. We established the new method that recovery oil and byproduct adsorbent by ultrasonic extraction-chemiccal activation and derect catalytic pyrolysis. The methods which not only achieve oil resource recovery but also solve environmental pollution problems can meet energy saving requirement and goals, fit to the sustainable development of the petroleum and chemical industries.(1) A new process for oily sludge treatment by ultrasonic extraction-pyrolysis which recovers oil resource firstly and then prepare adsorbent using ultrasound extraction residue was established.At the stage of oil recovery. Ultrasonic assisted extraction technology with gasoline as an extracting agent is applied for oily sludge treatment. Demulsifier and regulator system was studied and selected. The influence of extraction temperature, extraction time, ultrasound frequency and ultrasound intensity was investigated. The result suggests that the optimized conditions are:the volume ratio of extractor, regulator (waste water from oil-filed), and sludge is4:4:1;40℃; with40kHz150W ultrason, extraction for15min.83.7%of the total oil in the sludge can be recovered under the above conditions.At the stage of extraction residue process, a technology for preparation of adsorbent using extraction residue by chemical activation was studied. Four activation agents were selected and the results show that ZnCl2is the most appropriate activate agent for preparation of oily sludge-based adsorbent. Obtained by orthogonal experiment of ZnCl2-activation, the impact of various factors on the iodine number of sludge-based adsorbent as follows: activation temperature>activation agent concentration>activation time>the amount of the activation agent. Considering the economic efficiency and various factors, the optimum conditions for ZnCl2-activation were5mol/L,550℃and2h for the activation agent concentration, activation temperature and activation time, respectively, under these conditions, the iodine number of adsorbent is515.70mg/g.(2) A process for oily sludge treatment by catalytic pyrolysis was studied. Three types of catalysts (Alkali metal compounds、acidic catalys、solid acid catalysts) were investigated for oily sludge directly catalytic pyrolysis, the result show that ZnCl2and HZSM-5catalysts have better performance.Oily sludge pyrolysis process using HZSM-5catalyst was tested. The result suggests that the optimized conditions for oily sludge pyrolysis were5%,550℃and40min for the amount of HZSM-5, pyrolysis temperature and pyrolysis time respectively, liquid, gas and solid productivity were71.25%,17.03%and11.72%respectively, the oil recovery was64.14%, the iodine number of solid was327.34mg/g, the low calorific value of gas was7737.24kJ/g, the solidifying point of oil was-2.0℃under above conditions.Oily sludge pyrolysis process using ZnCl2catalyst was also tested. The result shows that under the conditions of10%,550℃and20min for the amount of ZnCl2, pyrolysis temperature and pyrolysis time respectively respectively by using wet mixing method, liquid, gas and solid productivity were78.43%,3.21%,18.36%, respectively, the oil recovery was74.15%, the iodine number of solid was425.97mg/g.