KR840001852B1 - Process for dewaxing wax oils troduced by hydrotreating - Google Patents

Abstract

Wax-contg. oil obtd. from refining raw oil contg. unsuitable lubricating oil constituents under a hydrocracking process is contacted with a dewaxing solvent in the presence of an alkyl acrylate ester polymer. The carbon number (n) of an alkyl of the polymer and b.p. (t, oC) of the wax-contg. oil satisfy the formula 6.4 + 0.0235t <= n <= 7.4 + 0.0235t. The polymer is employed in an amt. from 50-700 ppm (by wt.) based on the oil. Polymer pref. has a m.w. of 250,000 and an m.n. of 57,000. Pref. the solvent is a mixt. of MEK and toluene. Wax-contg. oil, which is refined by hydrocracking, is dewaxed efficiently by the use of this special filtration aid.

Description

Dewaxing of Wax-Containing Oils Prepared by Hydrogen Purification

1 is a graph showing the relationship between the number of atoms contained in the alkyl portion of an alkyl acrylate polymer used as a specific dewaxing aid and the filtration rate of hard waxy oil.

2 is a graph showing the relationship between the number of carbon atoms and the filtration rate of heavy beeswax.

3 is a graph showing the relationship between the number of carbon atoms and the content of heavy beeswax (filtration rate such as bright stoke).

FIG. 4 is a graph showing the relationship between the carbon atom number and the hard beeswax filtration rate. FIG. 5 is a graph showing the relationship between the carbon atom number and the medium beeswax filtration rate.

The present invention relates to an improved process for dewaxing beeswax oil produced by hydrogenation tablets.

In general, oils such as reduced pressure oil and deasphalted oil from which aromatic and undesirable components have been removed by solvent extraction using a solvent such as furfural have been used as raw material oils for producing lubricating oils and the like. Removal of these components enhances the viscosity index, color, and other properties to produce higher lubricating oils.

Recently, hydrogenation purification has been used instead of solvent extraction in order to obtain a desired raw material oil because hydrogenation purification is more economical than solvent extraction. The oil produced by the hydrorefining process is beeswax-containing oil, which is introduced into a dewaxing device for removing beeswax to prepare raw oil. It is known to use a dewaxing aid in a dewaxing device to increase the filtration rate.

The waxy oil produced by the hydrorefining process is very different from the composition of the conventional waxy oil produced by solvent extraction. In particular, the content of isopropane in the wax component of the wax-containing oil produced by the hydrorefining method is high. The properties of the beeswax component in the beeswax oil are different from those of the conventional beeswax oil produced by the conventional method.

When dewaxing beeswax oil produced by the hydrorefining agent, it was found that the amount of dewaxing aid needed to be greatly increased since the wax removal amount was small.

The present invention provides an effective dewaxing method for the treatment of beeswax oil produced by hydrorefining. Dewaxing efficiency can be significantly increased by the use of specific dewaxing aids, particularly when there is a correlation between the boiling point of the wax-containing oil.

Therefore, the present invention provides a method for dewaxing waxy oil produced by hydrorefining, wherein the waxy oil produced by treating the raw material oil under hydrocracking conditions to remove components undesirable for use as lubricating oil is alkyl. It is characterized by contact with a dewaxing solvent in the presence of an acrylate polymer. The raw material oil which has been used so far for the production of lubricating oil can be used as the raw material oil of the hydrogenation and purification method of the present invention method. These crude oils include heavy gas oils, reduced pressure fractions and deasphalted oils.

These crude oils provide oils for use as lubricating oils under hydrocracking drying drying, i.e., while undesirable components are removed by the hydrorefining process. This hydrogenation refining method is carried out under ordinary conditions for removing undesirable components such as aromatic components contained in the crude oil. Methods that can be used for hydrorefining methods include Gulf Lubricant Hydrogen Refining Methods include Gulf Lubricant Hydrorefining Method and IFP Lubricant Hydrorefining Method (O. & Rat. J., June 12, 1972, 94- Page 94: Aufrey, R. Oda (IFP Report 20992-A).

Dewaxing of the wax-containing oil produced by the hydrogenation refining method is carried out using various dewaxing solvents. Examples of dewaxing solvents that can be used are propane, a mixture of propane and butane, a mixture of methyl ethyl ketone (MEK) and toluene, and a mixture of MEK and methyl isobutyl ketone (MIBK). The dewaxing solvents inhibit the action of the dewaxing aid. Among these desorption solvents, mixtures of MEK and toluene (about 3: 7 to 6: 4) are particularly good. In the dewaxing step, the volume of the dewaxing solvent to beeswax oil is usually about 0.5: 1 to 10: 1, and about 2: 1 to 4: 1 is good.

According to the process of the present invention, the dewaxing is carried out in the presence of an alkylacrylate polymer. This alkylacrylate polymer acts as a waxing aid and is added to the waxy oil or a mixture of waxy oil and the waxy solvent.

Various alkylacrylate polymers can be used as the dewaxing aid of the present invention. In certain cases, the optimum alkylacrylate polymer depends on the boiling point of the waxed wax-containing wax. Remarkably good results are obtained according to the selection of these optimal alkylacrylate polymers and these optimal alkylacrylate polymers can be determined by the following formulas;

n

7.4+0.0235t6.4 + 0.0235t

n

7.4 + 0.0235 t

C)는 탈납된 밀랍함유유의 비점이다.Wherein n is the number of carbon atoms contained in the alkyl portion of the alkyl acrylate monomer constituting the alkyl acrylate polymer having an average carbon atom. The reason is that although a specific alkylacrylate monomer having the same n value can be used, a mixture of alkylacrylate monomers having different alkyl moieties is used for the production of alkylacrylate polymers. t (

C) is the boiling point of dewaxed waxy oil.

C일때, 알킬아크릴레이트 증합체의 알킬부분에 함유된 탄소원자의 수는 17-18(17.0

n

18.0)이며 밀랍함유유의 비점이 650

C일때에는 21.7

n

22.7이다.For example, the boiling point of waxy oil is 450

At C, the number of carbon atoms contained in the alkyl portion of the alkylacrylate polymer is 17-18 (17.0).

n

18.0) and the boiling point of waxy oil is 650

21.7 for C

n

22.7.

Based on the value of n, the optimal deasphishing aid can be easily determined. When the boiling point range of beeswax oil is wide, the average boiling point is used as the value of t. This average boiling point is Ind. Eng. Chem., 27,1460 (Nelson), is determined based on molecular weight and specific gravity.

Alkylacrylate polymers have an average molecular weight of about 140,000-300,000 and an average molecular number of 30,000-75,000. Better alkylacrylate polymers have an average molecular weight of 150,000-270,000 and an average molecular weight of 45,000-70,000.

In carrying out the method of the present invention, the amount of the dewaxing aid used is dependent on the filtration conditions and the like. It is usually about 50-700 ppm by weight of the wax-containing oil, preferably about 125-500 ppm. When the amount of the added lead-adhesive aid is about 700 ppm or more, the addition effect of the lead-adhesive aid cannot be obtained. In larger amounts, the filtration rate is lower than when no dewaxing aid is added.

C에서 7시간 가열하여 중합체탈납보조제를 생성시킨다.Alkyl acrylate polymers used as dewaxing aids in the process of the invention can be prepared by a variety of known methods. For example, 70 parts of a specific alkyl acrylate monomer (or a mixture of alkyl acrylate monomers) is mixed with 0.14 parts of azobisisobutyronitrile as a kerosene 30 parts catalyst, and 0.017 parts of dodecyl mercaptan is also mixed as necessary. A mixture of nitrogen in 70

Heating at C for 7 hours yields a polymer dewaxing aid.

The method of the present invention can be used for various dewaxing methods. An exemplary method is described as follows; The specific dewaxing aid of the present invention and the MEK-toluene mixed solvent are added to beeswax-containing oil produced by the hydrogenation purification method and dissolved uniformly by heating. The solution is cooled to dewaxing temperature using a heat exchanger and a cooler and then filtered in vacuo to separate the wax. The beeswax is washed with MEK-toluene mixed solvent to recover oil from the beeswax. The filtrate containing degreased oil and beeswax containing solvent were separately sent to a solvent recovery area to obtain dewaxed raw oil and wax for lubricating oil. A typical example of this method is the Texark method (Petroleum Refining, Vol. 15, No. 6, June 1936, pages 205-209).

In the dewaxing step of the present invention, the cooling rate and the filtration rate are accelerated. This has a number of advantages. Some key advantages of the present invention are as follows;

(1) The amount of raw material processed in the dewaxing step can be increased due to the high filtration rate and the productivity can be significantly increased with existing manufacturing equipment.

(2) Since the viscosity of the filler raw material mixture becomes low, the amount of solvent added to adjust the viscosity can be reduced.

(3) Since the amount of oil contained in beeswax to be removed is small, the yield of dewaxing can be greatly increased.

The method of the present invention can be effectively used in the field of lubricating oil.

The invention is described in more detail by the following examples and comparative examples.

Example 1

C; 90%점 : 470

C; 평균비점 : 450

C); (ii) 중(中)질유(10%점 : 468

C; 90%점 : 561

C; 평균비점: 550

C) : 그리고 (iii) 브라이트 스토크와 같은 중(重)질유(10%)점 : 552

C; 평균비점 : 650

C)를 각각 2.5 : 1,3.0 : 1 및 4.0 : 1부터 부피비의 MEK-톨루엔 혼합용제(부피비 4 : 6)와 혼합하였다. 이들 각 용액의 여러쌤플 각각에 서로다른 선정된 숫자의 탄소원자를 함유하는 알킬부분을 갖는 알킬아크릴레이트 250ppm을 첨가하였다. 생성된 혼합물을 60

C로 가열한 다음 3.5-7.0

C/분의 냉각속도로 -27

C±1

C까지 냉각하였다. 이때 -29

C로 유지하면서 서서히 교반하였다. 상기 혼합물을 상기온도에서 30분동안 정지시켰다. 그후, 직경 80mm의 프레임에 여과천을 마련하여 제조된 리프(leaf) 여과기를 사용하여 상기 혼합물을 하였고, 단위 시간당 여과된 혼합물의 양, 즉, 여과속도를 측정하였다. 그 결과를 제1-3도에 나타냈다(도면중 괄호내의 숫자는 탈납수율을 나타낸다).Three types of beeswax oils prepared by hydrogenation of each raw material oil, that is, (i) light (waxy) oils (10% point of distillation)

C; 90% Point: 470

C; Average Boiling Point: 450

C); (ii) Middle oil (10% point: 468)

C; 90% Point: 561

C; Average Boiling Point: 550

C): and (iii) heavy oil (10%), such as bright stoke: 552

C; Average Boiling Point: 650

C) was mixed with the volumetric MEK-toluene mixed solvent (volume ratio 4: 6) from 2.5: 1,3.0: 1 and 4.0: 1. To each of several samples of each of these solutions was added 250 ppm of alkyl acrylate having an alkyl moiety containing a different selected number of carbon atoms. The resulting mixture is 60

Heated to C and then 3.5-7.0

-27 at C / min cooling rate

C ± 1

Cool down to C. Where -29

Stir slowly while maintaining at C. The mixture was stopped at this temperature for 30 minutes. Thereafter, the mixture was prepared using a leaf filter prepared by preparing a filter cloth in a frame having a diameter of 80 mm, and the amount of the filtered mixture per unit time, that is, the filtration rate was measured. The results are shown in Figs. 1-3 (the numbers in parentheses in the figure indicate dehydration yields).

Comparative Example 1

Example 1 was repeated with the same oils as used in Example 1 except that no alkylacrylate polymer was added. The results are shown in 1-3 degrees.

Comparative Example 2

C, 90%점 : 470

C; 평균비점 : 450

C)을 제조하기 위해서 푸르푸랄로 용제 추출된 밀랍함유유와 중(中)질유(10%점 : 468

C; 90%점 : 561

C; 평균비점 : 550

C)을 제조하기 위해서 푸르푸랄로 용제 추출된 밀랍함유유를 각각 2.5 : 1 또는 3.0 : 1의 부피비로 MEK-톨루엔 혼합용제와 혼합하였다.Light oil (10% point: 388

C, 90% point: 470

C; Average Boiling Point: 450

To prepare C), waxy oil and medium oil extracted with furfural solvent (10% point: 468)

C; 90% Point: 561

C; Average Boiling Point: 550

In order to prepare C), furfural solvent extracted beeswax oil was mixed with MEK-toluene mixed solvent in a volume ratio of 2.5: 1 or 3.0: 1, respectively.

Other operations other than those described above were performed in the same manner as in Example 1. The results are shown in FIGS. 4 and 5.

EXAMPLES 2 and 3

The method of Example 1 was repeated except adding the ecosyl acrylate polymer in an amount of 125 ppm or 500 ppm. The results are shown in Table 1.

TABLE 1

Comparative Example 3-9

The method of Example 1 was repeated except that various dewaxing aids were used instead of alkylacrylate copolymers. The results are shown in Table 2.

TABLE 2

Example 4

C; 90%점 : 561

C; 평균비점 ; 550

C)를 상기 혼합된 용제와 기름을 부피비를 3 : 1로 하여 MEK-톨루엔 혼합용제와 혼합시켰다. 에이코실 아크릴레이트 중합체 250ppm을 다시 첨가하였다. 생성된 혼합물을 10l/hr속도로 냉각기에 공급한 다음 연속적으로 탈납시키기 위해서 올리버 여과기에 여과시켰다. 탈납된 기름 30.4l가 70%수율로 얻어졌다. 여과속도는 10l/hr(2.8ml/sec)이었다.In this example, the method of the present invention was carried out on a bench scale. 40 l of medium oil (10% point: 468) prepared by the hydrorefining method

C; 90% Point: 561

C; Mean boiling point; 550

C) was mixed with the MEK-toluene mixed solvent in a volume ratio of 3: 1 and the mixed solvent and oil. 250 ppm of the ecosyl acrylate polymer was added again. The resulting mixture was fed to the cooler at a rate of 10 l / hr and then filtered through an Oliver filter for continuous dewaxing. 30.4 liters of degreased oil was obtained in 70% yield. The filtration rate was 10 l / hr (2.8 ml / sec).

The method of Example 4 was repeated except adding the alkylacrylate polymer. The yield was 64% and 25.6 l of degreased oil was obtained with a filtration rate of 7.5 l / hr (2.1 ml / sec).

All technical documents referred to in this specification are incorporated by reference.

Claims (1)

In dewaxing beeswax oil produced by hydrorefining by mixing the beeswax oil and the dewaxing solvent, cooling it until the beeswax precipitates and separating the beeswax from the residual oil, the alkylacrylate polymer is added to the beeswax oil and the wax. A wax-dewaxing method of waxy milk produced by hydrogenation refining, characterized in that it is mixed with an auxiliary dewaxing solvent.

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