Oilfield Sludge Treatment And Oil Contents Of Sludge

It has been undertaken that the part research of the sub-project named Treatment on Produced Water by Polymer Flooding from Bohai sea oilfield of chemical flooding technology in sea oilfield(2011ZX05024-004)which derives from the Key Projects in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period by our laboratory.The separation agent which has high efficiency has been developed yet.However,the sludge can't be discharged directly because of the high oil contents of sludge after three-phase separation.The current method is to grind and refine the sludge into granules to make the particle size become much smaller,and then to inject it with chemical agent into underground.The process is complicated and expensive.It can't be directly discharged,according to the national standard called Control standards for pollutants in sludge from agricultural use in which oil contents of sludge should be less than 3000 mg per 1kg dry sludge.Therefore,it is of great significance to carry out the research on oil contents of sludge.In this dissertation,chemical washing method and extraction method was utilized to treat the two different oily sludge from Xinjiang and Guangxi.A new method was developed to reduce the oil contents of sludge after the three-phase separation.Guangxi oily sludge was treated by the mixture of chemical separation agent and extraction agent to form three phases,oil,water and sludge,and then the oil contents of sludge were analyzed.After the single separation agents and the composite reagents were studied,a new type of separation agent was developed.Just as the separation agent,the new extraction agent was developed.The effect of process parameters such as temperature,agitating time,agitating intensity and so on was investigated on oil contents of sludge.After Xinjiang oily sludge was divided into three phases by the chemical separation agent,the sludge was extracted.Based on laboratory test,the process conditions were adjusted furthermore while the on-site pilot scale test was made according to phenomena.The main research results were as follows:(1)For Guangxi oily sludge,the separation agent PN and KL exhibited effectively,the optimal formulation of the separation agent was that KL concentrationwas 0.1% and PN was 1 ug/g.The optimal formulation of extraction agent showed the concentrations of kerosene,toluene,BC was 45%,45%,10% respectively.The optimum conditions were as follows: temperature of 60?,settling time of 1h,agitating intensity of 160r/min,and the oily sludge/agent ratio of 4:1.Under these conditions,after washing three times,the oil contents of sludge reached 0.33%.(2)For Xinjiang oily sludge,separation agent already developed had good effect.The results indicated that under the conditions of temperature of 90?,agitating time of 40 min,agitating intensity of 300r/min,settling time of 1h,the oily sludge was divided into oil,water and sludge.Then sludge was extracted under the conditions of temperature of 50?,agitating time of 1h,agitating intensity of 150~180r/min,settling time of 1h.After washing two times,the oil contents of sludge was0.15%.When the extract agent was circularly used for 5 times,the oil contents of sludge were less than 2% still.(3)Pilot-test results showed that the oily sludge was divided into oil,water and sludge under the conditions of temperature of 90?,agitating time of 1h,agitating intensity of 435r/min,settling time of 1h.Then sludge was extracted under the conditions of temperature of 50?,agitating time of 1h,agitating intensity of330r/min,settling time of 1h,the oil recovery rate could reach 99.94%,the solid content of recovered oil was 0.62% and the oil contents of sludge was 0.14%.The sludge could be directly discharged.