RU2152427C1 - Lubrication oil fractions' deparaffination process - Google Patents

Abstract

FIELD: petroleum processing. SUBSTANCE: fractions are mixed with solvent; mixture is thermally treated and then cooled to filtration temperature to form suspension, which is separated on vacuum filter. Process is carried out in presence of a surfactant, in particular oxyethylated Mannich base in quantity 0.001 to 0.05 wt % based on raw material. As a result, yield of dewaxed oil is increased by 1.0-3.9%, viscosity index of oil is increased by 0.5-6.0 units, freezing temperature of oil lowered by 2-5 C, content of oil in gatch or petrolatum is reduced by 1.4-16.4 wt %. EFFECT: increased yield and improved characteristics of dewaxed oil. 1 tbl, 5 ex

Description

 The invention relates to the production of petroleum lubricating oils and may find application in the oil refining industry in the process of dewaxing of oil fractions by crystallization using solvents.

 A known method of dewaxing oil fractions by crystallization, according to which the removal of solid hydrocarbons (paraffins) is carried out using a mixture of MEK and toluene as a solvent (Kazakova L.P., Crane S.E.-M., Chemistry, 1978, 116-150 s. )

 This method is characterized by a number of disadvantages, namely a reduced filtration rate of a suspension of solid hydrocarbons in an oil solution, a low viscosity index of the obtained dewaxed oil.

The closest to the proposed invention in terms of technical nature and the achieved result is a method of dewaxing oil fractions by crystallization by mixing them with a solvent (MEK + toluene) and a modifying additive (surfactant), heat treating the mixture, cooling it to a filter temperature, followed by separation of solid hydrocarbons from the resulting suspension on vacuum filters. As a modifying additive, the product of condensation of pentaerythritol esters of fatty acids C ₁₆ -C ₃₀ with pyromellitic dianhydride in the amount of 0.001 - 0.1 wt.% On the feedstock is used (RF patent N 2023002, MKI C 10 G 73/04, 1991, Bulletin N 21, 11/01/94).

 However, the method is characterized by a low yield of dewaxed oil, its low viscosity index and high pour point, an increased oil content in a gache or petrolatum and a low filtering rate of a suspension of solid hydrocarbons.

 The invention is aimed at solving the problem of increasing the yield of dewaxed oil and its viscosity index, lowering the pour point of dewaxed oil, reducing the oil content in the gache or petrolatum and increasing the speed of filtering the suspension of solid hydrocarbons.

 The solution to this problem is mediated by a new technical result. This technical result is to increase the degree of influence of additives (surfactants) on the selectivity of the solvent.

 Salient features of the claimed technical solution: dewaxing of oil fractions of oil by crystallization by mixing them with a solvent and a surfactant, heat treatment, followed by cooling the mixture to a filtration temperature and separating the resulting suspension on a vacuum filter.

 Distinctive features: a surfactant is added to the feedstock or solvent, which is used as an Mannich's ethoxylated base in an amount of 0.001-0.05 wt.% Per feedstock.

 The oxyethylated Mannich base based on nonylphenol and tetramethyldipropylene triamine is a dark brown liquid containing 70% of the basic substance in isopropyl alcohol. It is used for the destruction of oil-water emulsions in the process of oil preparation; for the separation of heavy residues of oil sludge (TU 38-407-343-86).

According to the proposed method, the dewaxing of oil fractions of oil is carried out according to the method, in accordance with which the required amount of raw material is weighed into a round-bottomed or conical flask and the required amount of solvent (MEK + toluene) is added in accordance with the selected ratio. The flask is closed with a stopper with an opening into which a reflux condenser is inserted and, while stirring occasionally, the contents of the flask are heated in a water bath at a temperature of 50-60 ^o C until it is completely dissolved.

Next, the solution is cooled with continuous stirring at a speed of 2-3 ^o C per minute, first in the same bath with ice, and then with dry ice in alcohol. When the desired dewaxing temperature is reached, the separated solid hydrocarbons are separated from the solution by filtration on a Buchner funnel mounted in a cooling bath with a temperature of 3-5 ^o C lower than the filtration temperature. The funnel on the cork is inserted into a graduated receiver connected to a vacuum pump and begins to cool simultaneously with the dewaxed solution.

 After reaching the required temperatures of the dewaxing solution and the funnel (bath) and establishing the necessary vacuum, they begin filtering, fixing its speed.

 The cake formed during filtration is washed with a solvent cooled to the filtering temperature (MEK + toluene) in an amount of 150 wt.% Of the dewaxed raw material.

 Then the cake is dried under vacuum, the receiver is informed with the atmosphere and a spatula quantitatively transfer it to a weighed glass. From the cake and the filtrate, the solvent is regenerated in a stream of carbon dioxide, the residues are weighed and the material balance of the dewaxing process of the oil fractions of the oil is weighed.

 Before the start of heat treatment, a surfactant is introduced into the feedstock or solvent in the amount of Mannich's ethoxylated base in an amount of 0.001-0.05 wt.% For the feedstock.

The quality of dewaxed oil is evaluated by its kinematic viscosity at 50 and 100 ^o C, viscosity index, pour point; gacha or petrolatum - according to the melting temperature and the oil content in them.

 The essence of the proposed method for dewaxing oil fractions of oil is illustrated by examples.

 Example 1 (comparative).

The dewaxing of the raffinate of the selective purification of medium-viscous oil distillate is carried out according to the method described above, in the presence of Mannich's ethoxylated base supplied to the raw material in the amount of 0; 0,0005; 0.001; 0.002; 0.004; 0.005; 0.006; 0.008; 0.05; 0.06 wt.% For raw materials. The ratio of the solvent ratio (MEK + toluene) to the feed was 3: 1. The mass ratio of MEK: toluene in the solvent was 50:50. The final cooling temperature and the temperature of the solvent used for cold washing was equal to (-25 ^o C). The temperature of the solvent regeneration +120 ^o C. the residual pressure during filtration was 380 mm RT.article. The dewaxing results of the examples are given in table. 1.

 Example 2

 The dewaxing of the raffinate for the selective purification of a viscous oil distillate is carried out under the conditions of Example 1 in the presence of 0 oxyethylated Mannich base supplied to the raw material surfactant; 0,0005; 0.001; 0.002; 0.004; 0.006; 0.008; 0.02; 0.05; 0.06 wt.% For raw materials. The ratio of the solvent ratio (MEK + toluene) to the feed was 3: 1.

 Example 3

 The dewaxing of the raffinate of the selective purification of the deasphalting agent is carried out under the conditions of Example 1 in the presence of 0 oxyethylated Mannich base supplied to the raw material surfactant; 0,0005; 0.001; 0.002; 0.005; 0.007; 0.01; 0.02; 0.05; 0.06 wt.% For raw materials. The multiplicity of the ratio of solvent (MEK + toluene) to the raw material was 4: 1 (since for the deasphalting agent, the multiplicity is taken more).

 Example 4

 The dewaxing of raffinates of selective purification of medium-viscous and viscous oil distillates and deasphalting agent is carried out under the conditions of example 1 and example 3 in the presence of Mannich's ethoxylated base supplied to the solvent surfactant in an amount of 0.004; 0.006; 0.01 wt.% On raw materials, respectively.

 Example 5

The dewaxing of selective refining raffinates of medium-viscous and viscous oil distillates and deasphalting agent is carried out under the conditions of example 1 and example 3 in the presence of surfactant supplied to raw materials, which is a condensation product of pentaerythritol esters of C ₁₆ -C ₃₀ fatty acids with pyromelite dianhydride in an amount of 0.01, 0, 1 wt.% On raw materials.

 As can be seen from the table. 1, in the examples according to the invention, the yield of dewaxed oil and its viscosity index, the filtration rate of a suspension of solid hydrocarbons is higher, the pour point of the dewaxed oil and the oil content in gache or petrolatum is lower compared to the prototype.

 Example 4 confirms the invariability of the effect of surfactants on the process of dewaxing distillate and residual raffinates of selective purification, regardless of where the surfactant is supplied: to the feed or to the solvent.

 The quantitative limits for the use of surfactants by the Mannich's ethoxylated base are determined by the fact that when it is added to the feedstock or solvent in an amount of less than 0.001 wt.% For the feedstock during the dewaxing of raffinates for the selective purification of medium-viscous and viscous oil distillates and deasphalting agent, accordingly, it practically does not affect the properties of the solvent (IEC + toluene), and in amounts of more than 0.05 wt.% on raw materials, respectively, does not give an additional positive effect.

Thus, the use of the proposed method for dewaxing oil fractions of oil by crystallization, using solvents (MEK + toluene) and surfactants of Mannich's ethoxylated base in an amount of 0.001 - 0.05 wt. % of raw materials provides the following technical and economic advantages compared with the prototype (with the optimal amount of surfactant introduced and the conditions for the dewaxing process), when using raw materials 1, raw materials 2, raw materials 3, respectively:
- an increase in the yield of dewaxed oil by 1.0; 3.9; 3.4 wt.%;
- increase in its viscosity index by 6.0; 0.5; 2.4 units;
- a decrease in its pour point by 2; 5; 7 ^o C;
- a decrease in the oil content in gache or petrolatum by 1.4; 16.4; 6.7 wt.%;
- an increase in the rate of filtration of a suspension of solid hydrocarbons by 55; 36; 34 ml / min.

Claims (1)

 The method of dewaxing oil fractions of oil by crystallization by mixing them with a solvent and a surfactant, heat treatment, followed by cooling the mixture to a filtration temperature and separating the resulting suspension on a vacuum filter, characterized in that 0.001 Mannich base is used as a surfactant in an amount of 0.001 - 0.05 wt.% For raw materials.

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