Study On Oily Sludge Treatment Technology Of The Second Oil Production Plant Of Changqing Oilfield

Oily sludge which has high crude oil recovery value is one of the key pollutants in the production operation process of the petroleum and chemical industry.Because of its complicate compositions and bulky volume,a large area of land would be occupied by the bulky oily sludge without process,and the effective use of the land would be decreased.The ecological environment and economic development of the oil and gas fields would be affected seriously by the toxic and harmful substances in the oily sludge.So the harmless treatment and comprehensive disposal of the oily sludge has become a key research field of domestic and foreign petrochemical.At present,the treatment of the oily sluge was researched extensively all over the world,but choosing an economic and technology feasible method was particularly critical due to the relative limitations of each kind of processing method and technology because of the difference on qulity and composition of the oily sludge.The oily sludge from the Second oil production plant of Changqing Oilfield was taken as the research object in this paper.The best process conditions of the Chemical thermal washing method,the ultrasonic technique,and the organic combination of the two methods were researched in this paper,and the results of the three process methods were also compared.The risk characteristics of the oily sludge with treatment of the two methods organic combination of the Chemical thermal washing method and the ultrasonic technique was identified.The feasibility of the combination method was explored tentatively.It offered technical support for the wide application.The main results are as follows:(1)The influence of the factors including chemical agent dosage,thermal washing temprature,solid-liquid ratio,thermal washing time,stirring intensity,pH,thermal washing series on the oil removal efficiency of the Chemical thermal washing method was researched in the experiment.The best process conditions were determined at that chemical agent dosage is HP-003(sodium silicate,sodium dodecyl benzene sulfonate,peregal O-20 with the ratio of2:2:1)with 1.0g/L,thermal washing temprature is 75?,solid-liquid ratio is 1:6,thermal washing time is 40 minutes,stirring intensity is 150r/min,pH is 8,and thermal washing series is one.The oil removal rate of the oily sludge on chemical thermal treatment method under the best condition could reach 86.7%.(2)The influence of the factors including ultrasonic power,ultrasonic frequency,temprature,ultrasonic time on the oil removal efficiency of the ultrasonic technique was researched in the experiment.The best process conditions were determined at that ultrasonic power is 340 W,ultrasonic frequency is 28 kHz,temperature is 60?,and ultrasonic time is15 minutes.The oil removal rate of the oily sludge on ultrasonic technique under the bestcondition could reach 86.7%.(3)The two methods of the Chemical thermal washing method and the ultrasonic technique were combinated under the best process conditions.The oil removal rate of oily sludge could be up to 99.4% and the oil ratio is less than 2% while the dehydration rate of the sluge phase is as high as 94.8%,with the combined method.The removal effect was obviously better than each single processing method.In the exploring experiment of chemical agent dosage,the best adding amount was determined at 0.3g/L of the combined process method.Compared with the dosage of 1.0g/L under the Chemical thermal washing method,the usage amount was reduced greatly.(4)The risk characteristics of corrosion(pH)and heavy metal leaching toxicity of sluge under the treatment of the combined process method was identified,and the result showed that the sludge is not corrosive(pH)or leaching hazardous toxic.And the water content rate,oil content rate,pH and heavy metals in sludge were all under the limit requirements of the Control standards for pollutants in agricultural sludge(GB 4294-1984),the pollution control standards of oily sludge comprehensive utilization in oil field(DB 23/T1413-2010),and the control limits of oily sludge disposal and utilization(DB 61/T 1025-2016).The basis was provided for the following comprehensive utilization.The above results showed that the oil removal effect of the oily sluge under the combined process method was better with technical feasibility,resource utilization and harmless disposal.