A kind of isopropanol urea dewaxing method

Abstract

The invention relates to a dewaxing method of isopropanol urea. The dewaxing method specifically comprises the following steps: mixing raw material oil with an isopropanol urea water solution, adding the mixed solution into a reactor, carrying out complexation, operating the reactor under a reduced pressure condition, circulating gaseous effluent on the top of the reactor back to the reactor after cooling, returning partial reactants obtained at the bottom of the reactor to the reactor, and carrying out subsequent separation on the rest reactants by virtue of a decomplexation settling and washing tower. According to the dewaxing method, by virtue of reduced pressure operation, heat released by complexation of n-alkanes in the urea and the raw martial oil is absorbed when isopropanol and water in the isopropanol urea water solution are converted from a liquid state to a gas state by virtue of gasification, so that the requirement of complexation to the temperature is met; other cooling mediums do not need to be introduced, so that the defect that the reaction temperature is controlled by virtue of a large amount of underground water in the prior art is overcome, and the underground water resource is saved; the technique can be further applied to areas which are relatively deficient in water resources.

Description

technical field [0001] The invention relates to a dewaxing method, in particular to an isopropanol urea aqueous solution complexation reaction dewaxing method. Background technique [0002] The urea dewaxing technology uses the basic principle of contacting urea molecules with n-alkane to form helical hexagonal crystals around n-alkane to form a complex that is immiscible with oil, thereby separating n-alkane from oil. The pore size of the helical hexagonal crystal is 0.525nm, which can also be regarded as an organic molecular sieve with a single pore size. [0003] Isopropanol urea dewaxing is to mix urea with a certain proportion of water and isopropanol, and heat the mixture until the urea is completely dissolved to form a uniform solution. After the contact of alkanes, the temperature of the reaction mixture is gradually reduced, and the urea and n-alkanes react to form an oil-insoluble complex, so that the n-alkanes (wax) are released from the oil. As the reaction tem...

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Problems solved by technology

[0005] Due to the isopropanol aqueous solution urea dewaxing technology, when water is used as the refrigerant, the reaction system needs a large amount of cooling water, and the water temperature requirement is also low, and the heat exchange method is indirect heat exchange, which will cause the reactor directly in contact with the cooling medium water The wall temperature is lower than the temperature inside the reactor, the urea and the normal alkanes in the raw oil will react on the wall to form a complex, and attach to the tube wall to form a wall phenomenon, which reduces the heat transfer effect. It is easy to block the pipeline for a long time and affect the normal production

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