Research On The Combined Chemical Washing Process For Oily Sludge Cleaning And Recovery Of Oil

This paper investigates the logical technology of chemical heat washing and recovery of oil for treating oily sludge which comes from the process of producing, storing, carrying for crude oil and dealing with oily sewage in petrifaction industry. And in allusion to the key chemical problem, the paper also does literature analysis, locale investigation, experiment filtration and project equipment design.The oily sluge's source, character and environmental harm are summarized in this thesis. Various ways of present oily sludge disposal, advantages and disadvantages of each technology, techonic nodus and economic feasibility have been categorized in parallel according to pretreatment, core treatment and final disposal. On the basis of comparative analysis of internal and external development in this realm, the feasibility of chemical heat washing oily sludge is testified.Four types of representative oily sludge such as oily sand, sludge from oil tank and oil ship, and suspended oily sludge are chosen in the tests. By ingredient analysis, we find that main composition of the oily sand is sand. Sludge from oil tank and oil ship contains high hydrocarbon content which can be recovered. Water in suspended oily sluge is more than three others, so that dehydration and decrement of sludge volume become our main task. In order to investigate the optimal working parameters, a series of single factor studies, including washing temperature, time, pH and ratio of solid to liquid as well as orthogonal test have been conducted. Experimental results show that suitable operate condition of washing temperature, ratio of solid to liquid, time and pH was 60 to 80 degree, 1:5 to 1:7, 30 min and 9 to 11 respectively. By medicament rinse choice test, we found that Na₂SiO₃ · 9H₂O is good for sludge disposal from oil tank and DL-100 is effective on demulsifying suspended oily sludge. After two times washing, 96% oily was removed from oily sand, the oil recoveries of sludge from oil tank and oil ship are 62% and 94% respectively and the volume of suspended oily sludge is one third of primary one under the optimal working condition.From the experimental phenomena and the data analysis, the technology chemical heat washing multilevel separation disposal of oily sludge has been achieved, viz. oily sludge, heat washing, machine whisk, muti-phase separation and matriel distributary. The design techinics are made up of four areas, such as pretreatment area, washing area, waste water treatment and assistant equipment area. Pretreatment area includes raw material pond, space grid with some pumps, the water and sludge mixing tank. In washing area, there are the first, second, thirdwashing pond and catchment pond. A flotation apparatus operates in waste water treatment area. There are many pumps and valves, the dish tube heating apparatus and the oil tank et al. in assistant equipment area. This method is flexible and fairly effective for disposing many kinds of oily sludge and recovery of oil.This technological process has been put to use in an oil field. Oil recovery is up to 90% and good effect has been achieved by the autoptic running.