Efficient extraction method for oil-containing sludge

Abstract

The present invention provides an oil-containing sludge extraction method with excellent performances. According to the method, oil-containing sludge and a small amount of an extraction solvent are subjected to a high temperature and autogenic pressure in a closed container so as to make the solvent permeate and replace the oil component in the oil mud to a great degree, and then the oil component is completely separated under drive of the high dose solvent, wherein the extraction solvent contains a main agent A, a vice agent B and an auxiliary agent C, wherein the main agent A is distillate oil with a boiling range of 110-135 DEG C, the vice agent B is distillate oil with a boiling range of 140-150 DEG C, the auxiliary agent C is distillate oil with a boiling range of 80-100 DEG C or an industrial pure product, and the distillate oil is naphtha, light oil and the like. According to the extraction method, during the extraction process, the extraction time is short and the extraction effect is prominent, and the resource target of the oil-containing sludge is achieved to a greater degree.

Description

technical field [0001] The invention relates to an extraction method of oily sludge, in particular to an extraction method for tank bottom sludge produced in crude oil storage and transportation process and oily sludge produced in oil refineries and oil refinery sewage treatment plants. Background technique [0002] Refining and chemical enterprises produce a large amount of oily sludge in the process of oil storage and transportation, refining and wastewater treatment. They mainly come from grease traps, flotation tanks, crude oil dehydration tanks, storage and transportation tanks, and waste oil tanks. The composition of these sludges is complex, containing a large amount of aged crude oil, wax, asphaltene, colloids and suspended solids, bacteria, etc., and a large amount of coagulant, corrosion inhibitor, scale inhibitor, bactericide, etc. are also added in the sewage treatment process Water treatment chemicals, which brings great difficulty to sludge treatment. At prese...

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Problems solved by technology

However, the solvent used is highly toxic (especially xylene), which poses a greater safety hazard to the surrounding environment and operators

And the amount of low-boiling point hexane is large, and the loss in the solvent recovery stage will be large, resulting in a decline in process economy

[0009] In summary, the raw materials currently used as oily sludge extraction solvents mainly include light coal tar, petroleum ether, naphtha, light oil, benzene, toluene, butanone and other industrial products or wide boiling range combination solvents, although A certain extraction effect can be achieved, but literature data prove that the extraction of oily sludge with the above solvents, the extracted organic products are difficult to exceed 60% of the total organic components in the oily sludge, and the extraction solvent will be recycled during the recycling process. There is a relatively large amount of loss, and the general loss can reach more than 6%, which affects the economic performance of oily sludge extraction technology and delays the popularization and application of this technology

Single solvents, such as benzene, toluene, methyl ethyl ketone, etc., due to the singleness of their molecular structure, have certain compatibility limitations with petroleum substances with complex structures in oily sludge, resulting in that the extraction effect cannot be greatly improved

Single petroleum products, such as coal tar, petroleum ether, naphtha, light oil, etc., have high solubility to petroleum substances with complex structures in oily sludge, but due to the wide boiling range of such solvents, Moreover, the content of low-boiling range oil is high, which requires harsh extraction process equipment to avoid explosion hazards caused by oil and gas leakage. At the same time, low-boiling range oil is difficult to recover in the solvent recovery stage, resulting in greater solvent loss.

A solvent with a wider boiling range, such as CN200410050782, uses a wide boiling point oil (100-500°C) as solvent oil extracted from oily sludge. This process requires a roasting temperature above 500°C to separate the solvent oil from the dry sludge. The process is complex , high energy consumption, while recovery solvent loss is also high and the composition is not constant

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