SK146296A3 - High penetration, low viscosity paraffin wax and process for its production - Google Patents

Abstract

The invention relates to a high penetration - minimum value 30 0.1 mm at 25 DEG C - and low viscosity - maximum value 10 m<2>/s - paraffin wax. The invention also relates to a process for producing said paraffin wax by redistilling a mixture of slack waxes and de-oiling the resulting individual fractions I, II, III and IV (the residue) to obtain foot oil I, foot oil II, foot oil III and foot oil IV. According to the invention at least two of the resulting foot oils are mixed with one another and optionally with up to 65 w/w % of a foot oil resulting from non-redistilled slack waxes to obtain a final mixture containing at least 15 w/w % of foot oil IV (petrolatum oil), and this mixture is de-oiled in a manner known per se in an apparatus used for de-oiling of slack waxes with a solvent mixture comprising ketones and aromatics with a ketone content of not less than 29 % by volume, wherein dissolution and mixing are performed at temperatures not higher than 125 DEG C and crystallization is performed at a final cooling temperature not less than -17 DEG C.

Description

PARAFFIN WAX ON LOW VISCOSITY AND HIGH PENETRATION AND METHOD OF PRODUCTION

Technical field

The present invention relates to paraffin wax of low viscosity and high penetration and particularly advantageous properties and process for its production.

According to the general terminology of the oil industry, "paraffin waxes" are solid hydrocarbons, consisting mainly of paraffins in the chemical meaning of the word, corresponding to the general formula C _n H _2n +2, but also containing cycloalkanes. Moreover, in large molecules of petroleum waxes (C 1 or more), normal-, iso- and cycloparaffin structures can occur in one single molecule. Then no uniform terminology can be accepted for the definition and classification of diesel waxes.

Hungarian authors have classified paraffins as liquid, macrocrystalline, intermediate and microcrystalline paraffins (Feund, M., Csikós, R., Keszthelyi, S., Mózes, Gy., Paraffin Products, Properties, Technologies, Application, Akadémiai Kiadó, Budapest, 1982, p. 19). Microcrystalline paraffins are divided into brittle and malleable, and the latter group is divided into elastic and plastic waxes.

Macrocrystalline paraffin waxes may be classified on the basis of their pour point or degree of refining. Those with a pour point below 45 ° C are soft paraffin waxes, hard paraffin waxes have a pour point above 45 ° C, Ubbelohde drip points between 50 to 58 ° C and penetration values at 25 ° C and 0.1 mm are between 12 to 16 .

According to H. Bennett, paraffin waxes are characterized by pour points between 27-68.9 ° C and penetration values at 32 ° F and 0.1 mm equal to 16 (Bennett, H., Industrial Waxes, Chem. Publ. Co. Inc., New York, NY, 1975, p. 14). Petroleum waxes are generally divided into paraffin waxes and microcrystalline waxes based on their freezing point and refractive index at 210 ° C, while semi-microcrystalline waxes have a viscosity of 210 ° C below 10 mm ² / s (also p. 101).

BACKGROUND OF THE INVENTION

A number of methods for producing petroleum waxes have been known prior to the present invention. In particular, these processes use light or medium vacuum fractions of paraffinic, sometimes intermediate, crude oil as the starting material. Such distillates are used in the production of lubricants and dewaxing is an important step in this process. Dewaxing can usually be achieved by direct cooling followed by pressure filtration in several stages, providing the first "+ slack" and then slack as a by-product. These slack waxes are used as raw materials for the production of paraffin waxes, in particular by a technology called 'sweetening'. New technologies apply selective solvents prior to cooling to facilitate filtration and improve the processability of viscous distillates and residual oils. The selective solvents release the paraffin components and intermediate hydrocarbons increasing the solidification point (structurally between the paraffins and the oils) in the solid phase and can then be separated from the oils by filtration. Both slack wax and oil contain a solvent which must be evaporated. Slack waxes obtained as by-products are raw materials for the production of paraffin waxes. In this method, the application of solvent technologies to the separation of low oil paraffins, like dewaxing, increases the capacity and the equipment can operate continuously,

Slack waxes are diluted with solvent. Most commonly, ketone-aromatic type solvents are used, wherein the ketone component may be acetone, methyl ethyl ketone or methyl isobutyl ketone and the aromatic component is benzene, toluene or a mixture thereof (currently benzene is used less frequently because of its hazardous nature). This solvent dissolves slack by heating. The solution is then cooled and therefore the paraffin wax crystallizes and can be separated by filtration. Quality requirements prescribe low oil content, maximum values are 2% by weight (hereinafter:% by weight) for technical quality products, 1% by weight. for quality products and 0,5% by weight. for products meeting the quality criteria for food. Multiple filtration is used to meet the requirements and the paraffin filter cake is washed with solvent. The resulting product of this production method is paraffin wax. Foot oil, used mainly as fuel oil, but occasionally added to FCC (Fluid Catalytic Cracking) because they are easier to crack.

Macro- or microcrystalline paraffin waxes are widely used for various applications. In the US, more than 60% of them are used for the production of laminate films and paper for the food industry and about 18% for the production of candles. In Europe, on the other hand, 43 to 55% of paraffin waxes are used for candle production and 25 to 26% for other industrial purposes.

As the reference publications show, paraffin waxes are hard, have low penetration values and are therefore brittle and of little use, for example, for coating purposes. Their flexibility is improved by micro waxes and plastics.

The authors of the USSR patent no. 1121284: "Process for the manufacture of plastic ductile paraffins" found that the plasticity of paraffins is sometimes an important property and describes a method for producing plastic paraffin waxes having a low pour point of 37 to 45 ° C and containing crystalline hydrocarbons containing iso- and cycloparaffin containing 20 to 35% by weight. This plastic paraffin wax is then mixed with hard paraffin wax in a weight ratio (10:90) to (90: 1). Their method differs from general practice. The raw material is not slack wax but a fraction boiling between 280 to 470 ° C, which has been de-oily in a ketone-aromatic type of selective solvent, providing a paraffin wax with a pour point of 50 to 55 ° C and an oil content of 0.5 to 2.3% by weight The filtrate of the first filtration stage is then dewaxed by crystallization at (-20) to (-30) ° C, followed by filtration according to general practice in the oil industry. Low-freezing slack wax, which is obtained as a by-product, is de-oily again. The resulting plastic paraffin wax having the above properties is mixed with hard paraffin wax.

The properties of the plastic component given in the examples cited by the Soviet patent are listed in Table 1.

Table 1

Properties of plastic paraffin wax according to USSR P no. 1121284 Freezing temperature (° C) 38.3 - 50.5 Oil content (% by weight) 1.0 -3.0 Content of n-alkanes (% by weight) 64.5 -91.3 Viscosity at 100 ° C (mm ² / s) 2.8 -3.08 Penetration (cone) at 20 ° C 13.0 -49.0

This process has some disadvantages: following separation of the hard paraffin waxes, a "low freezing point slack wax" can be obtained as a raw material for the next stages by a dewaxing step with an excessively high energy consumption; whereas the raw material for the first step is a low-viscosity vacuum fraction and not a finished product, therefore the dewaxed oil product is a low-value distilled oil. Moreover, the isoalkane content of the final product, which increases plasticity, is relatively low.

SUMMARY OF THE INVENTION

The aim of our experiments was to develop a process for producing plastic paraffin waxes having low viscosity and high isoalkane content. The feedstocks are light, medium and heavy vacuum fractions of paraffinic and intermediate crude oil (originally produced as a lubricant feedstock) and / or its raffinates after treatment with a selective solvent, preferably N-methyl-2-pyrrolidone. They were dewaxed with a ketone-aromatic solvent, preferably a mixture of methyl ethyl ketone and toluene in a ratio of (30 to 70): (70 to 30)% by volume, the slack wax by-products were then mixed in their yields and redistilled in vacuo. This is a justified operation since the narrow-boiling fractions exhibit advantageous properties in the de-oiling step of paraffin production due to their more uniform crystalline structure. In addition, about 30% macrocrystalline paraffin content consisting of heavy fractions or their raffinate having a pour point of between 60 and 62 ° C (third fraction of vacuum distillation) can be obtained. The residue is a suitable raw material for the production of paraffin waxes, preferably with a freezing point at 62 to 66 ° C. The method provides three vacuum distillates and a residue, which are referred to as slack I, slack II, slack III and slack IV (residue) in the following sections of the description. Their properties are shown in Table 2.

Table 2

Main characteristics of de-oiled raw materials features Gaci Gáč II Gáč Hl Gáč IV Density at 70 ° C 0.76 - 0.80 0.77 to 0.81 0.79 - 0.82 0.79 - 0.83 Freezing temperature (° C) 44-50 50-54 55-60 59-65 Viscosity at 100 ° C (mm ² / s) 2.0-3,0 3.1 to 4.3 4.4 - 6.2 5.5 - 7.9

De-oiling was carried out by known methods and resulted in four paraffin waxes of different quality, which have no further meaning in relation to our invention, and four waxed oils. They are referred to as effluent oil 1, effluent oil III, effluent oil III, and effluent oil IV (petroleumciium oil). The properties of these wasted oils are shown in Table 3.

Table 3:

Properties of sweated oils Sweated with oil Sweaty Oley II Spilled oil III Spilled oil IV Density at 70 ° C 0.76 to 0.81 0.77 - 0.82 0.79 - 0.84 0.80 - 0.85 Viscosity at 100 ° C (mm ² / s) 2,0 -3,1 3.2 -4.4 4.0 -6.2 6.2 -8.8 Drip temperature [(M), ° C, min] 140 150 160 170 Freezing temperature (° C) 10-35 12-38 15-40 20 -45

Surprisingly, further investigation has shown that the swelled oils and especially mixtures thereof used previously as fuel oils or feedstocks for fluid catalytic cracking are an excellent starting material for producing low viscosity and high penetration soft paraffin waxes at suitably selected conditions.

The invention relates to a process for the production of high-penetration and low-viscosity paraffin waxes (minimum penetration at 25 ° C and 0.1 mm is 30; maximum viscosity at 100 ° C is 10 mm ² / s) by redistillation of slack wax mixture and de-oiling the resulting individual fractions I, II, III, and IV (residue) to obtain sweaty oil I, sweaty oil II, sweaty oil III and sweaty oil IV. According to the invention, at least two of the resulting sweated oils are mixed with one another, optionally up to 65% by weight. sweat oil resulting from non-distilled slack waxes, to obtain a finished blend containing at least 15% by weight. and the blend is then de-oily in a manner known per se in the apparatus used for de-oiling the slack waxes with a solvent mixture containing ketones and flavorings with a ketone content of not less than 29% by volume. the mixing is carried out at temperatures not higher than 125 ° C and crystallization takes place at a final cooling temperature not lower than -17 ° C.

Two blends of foot oils were prepared for testing with the following composition (in% by weight):

"And" "B" sweat oil 0 10-25 sweated oil II 70-30 20- 45 sweated oil III 15-35 15-35 sweat oil IV (petroleum jelly) 15-55 15-35

The mixtures were de-oiled by a method similar to that used in the manufacture of paraffin waxes but under different conditions. The solvent used was either a mixture of acetone, methyl ethyl ketone and toluene in a ratio of (30 to 70): (0 to 10) :( 70 to 30)% by volume, or a mixture of methyl ethyl ketone, acetone and toluene in a ratio of (30 to 70): (0 to 10): (70 to 30)% by volume. The solvents may also contain water or other impurities in an amount of up to 5% by volume. The solvent was used in a five- to twelve-fold amount for the oil sweat mixture and the final crystallization temperature was maintained in the range of (-15) to (+ 1) ° C. Filtration was also carried out at this temperature. Rotary vacuum filters were used for filtration. Depending on the known quality requirements of the final product, the filter cake was reconstituted once or twice with solvent and washed with solvent after each filtration step.

The soft paraffin wax of the invention was obtained after removal of the solvent from the crystalline phase and removal of the solvent from the filtrate afforded a secondary effluent oil. The characteristics of the soft paraffin wax are shown in Table 4.

Table 4:

Characteristics of high penetration and low viscosity paraffin waxes Viscosity at 100 ° C (mm ² / s) 3.20- 10.0 Freezing temperature (° C) 42.0 - 59 Penetration at 25 ° C, 0.1 mm 30.0 to 170 Oil content (% by weight) 0,6 -42 Minimum amount of non-normal alkanes (% by mass - gas chromatography) 37.0

Filtration of soft paraffin waxes may occasionally be aided by crystallization excipients.

At least two of the sweaty oils obtained as by-products in the redistillation of slack waxes to the near-boiling fraction and de-oiling of these fractions are mixed to a certain extent. The resulting mixture is reprocessed in a paraffin wax production plant using solvent technology to obtain a soft paraffin wax and a secondary sweat oil. Thus, our invention can be applied to blended oil blends as base materials for the production of soft paraffin waxes, where one type of component of said blend is blended oil produced by de-oiling undistilled slack waxes as described above and the other type of component is blended oil produced by de-oiling slack waxes obtained from. light and / or medium vacuum fractions or their refiners.

DETAILED DESCRIPTION OF THE INVENTION

The essence of our invention is further elucidated by the following specific examples of low viscosity and high penetration paraffin waxes:

Example 1% by weight. of sweated oil II, 29% by weight. of oil spilled III and 48 wt. The sweating oil IV is mixed. The characteristics of the mixture are shown in Table 5.

Table 5

Main Characteristics of the Spent Oil Mixture of Example 1 Density at 70 ° C 0,814 Freezing temperature (° C) 39.0 Viscosity at 100 ° C (mm ² / s) 5.62 Oil content (% by weight) 21.7 Flash point (° C) 238.0 Boiling point in vacuum distillation (converted to atmospheric pressure) => initial (° C) 351.0 => final (° C) 532.0 Color 4.5 Refractive index at 70 ° C 1.4520

This starting mixture was diluted with 8.5 times the amount of solvent containing 51% by volume, acetone, 4% by volume, methyl ethyl ketone, 44% by volume, toluene and 1% by volume of water. The final crystallization temperature of the de-oiling process was -7 ° C, and this was also the filtration temperature. The filter cake was washed with an equal (one-fold) amount of cold solvent in a rotary vacuum filter, then suspended in a double amount of solvent, filtered again, and then washed with a 1.5-fold amount of solvent. The solvent present in the soft paraffin wax and in the filtrate was removed by distillation according to established practice. This yielded a 44% yield of soft paraffin wax, measured by weight of the starting mixture. Its properties are shown in Table 6.

Table 6

Characteristics of soft paraffin waxes according to Example 1 Freezing temperature (° C) 46.2 Oil content (% by weight) 3.9 Viscosity at 100 ° C (mm ² / s) 5.12 Penetration at 25 ° C, 0.1 mm 168.0 n - alkanes (% by weight) 43.6 alkanes other than n-alkanes (% by weight) 56.4 Mean molecular weight 433.0

Example 2% by weight. oil swelled by deoiling II, 18% by weight. oil swelled by de-oiling III and 54% by weight. The oil swelled by de-oiling IV (Vaseline Oil) was blended to obtain a blend with the properties listed in Table 7.

Table 7

i Characteristics of the starting material used in Pri kla a e 2 ' Density at 70 ° C 0,810 Freezing temperature (° C) 38.0 Viscosity at 100 ° C (mm ² / s) 5.76 Oil content (% by weight) oo 7 - - 4 · Flash point / M / (° C) 235.0 Boiling points under vacuum distillation (calculated at atmospheric pressure): => start (° C) 335.0 => final (° C) 526.0 Color 3.5 Refractive index (70 ° C) 1.4481

The warm starting mixture was diluted with a 6.5-fold amount of solvent containing 55% by volume, methyl ethyl ketone, 4% by volume, acetone, 39% by volume, toluene and 2% by volume. water. The solution was cooled to a final crystallization temperature of 11 11 C and filtered. The filter cake in a rotary vacuum filter was washed with 1.5 times the cold solvent, then suspended in 2.5 times the solvent having the same temperature, filtered again and washed with twice the solvent at the same temperature. The solvent present in the soft paraffin wax and in the filtrate was removed by distillation according to conventional practice. The characteristics of the soft paraffin waxes obtained according to Example 2 are shown in Table 8. The product was obtained with a 42% yield calculated on the weight of the starting mixture.

Table 8

Soft Paraffin Characteristics of Example 2 of new wax Freezing temperature (° C) 45.8 Oil content (% by weight) 4.1 Viscosity at 100 ° C (mm ² / s) 5.10 Penetration at 25 ° C, 0.1 mm 137.0 n-alkanes (% by weight) 47.5 Alkanes other than n-alkanes (% by weight) 52.5 Mean molecular weight 419.0

Example 3% of oil swelled by deoiling II, 22% by weight. of oil swelled at the slackening agent III and 50% by weight. Vaseline oil was mixed. The properties of the mixture are shown in Table 9.

The starting mixture was diluted with an 11-fold amount of warm solvent containing 44% by volume, acetone, 6% by volume, methyl ethyl ketone, 48% by volume, toluene and 2% by volume. water. The solution was cooled to -4 ° C and filtered. The filter cake was washed with 3 times the amount of solvent, suspended in 3.5 times the amount of solvent at -4 ° C, filtered again and washed with the same amount of solvent. The solvent was then removed in the same manner as described in Examples 1 and 2. Plastic paraffin wax was obtained in 57% yield calculated on the amount of starting material. Its characteristics are shown in Table 10.

Table 9

Characteristics of the starting mixture used in Example 9 Density at 70 ° C 0,821 Freezing temperature (° C) 44.5 Viscosity at 100 ^° C (mm ² / s) 5.93 Oil content (% by weight) 25.9 Flash point (° C) 238.0 Boiling points under vacuum distillation (calculated at atmospheric pressure): => initial (° C) 333.0 => final (° C) 567.0 Color 3 Refractive index (70 ° C) 1.4529

Table 10

Product characteristics according to Example 3 Freezing temperature (° C) 48.1 Oil content (% by weight) 2.1 Viscosity at 10 ° C (mm ² / s) 5.72 Penetration at 25 ^° C, 0.1 mm 110 n-alkanes (% by weight) 43.2 alkanes other than n-alkanes (% by weight) 56.8

Example 4

The four oils swelled when de-oiling oil were mixed: 12% by weight. of oil I, 41% by weight. of oil II, 31 wt. oil III and 48 wt. Vaseline oil. The properties of the mixture are shown in Table 11.

Table 11

The characteristics of the base material of Example 4 Density at 70 ^° C 0,801 Freezing temperature (° C) 36 Viscosity at 100 ^° C (mm ² / s) 4.83 Oil content (% by weight) 24.8 Flash point (° C) 217 Boiling points under vacuum distillation (calculated at atmospheric pressure): => initial (° C) => final (° C) 302 518 Color 3.5 Refractive index, 70 ^° C 1.4416

The warm starting mixture was diluted with a 5.8-fold amount of solvent containing 29% by volume, methyl ethyl ketone, 4% by volume, acetone, 65% by volume, toluene and 2% by volume. water. Mixing was performed at 121 ° C in a closed device, then the solution was cooled to a final crystallization temperature of -17 ^° C and filtered. The filter cake in a rotary vacuum filter was washed with a 1.5-fold amount of cold solvent, suspended in a 2-fold amount of solvent at -17 ° C, filtered again and washed with a 2.5-fold amount of solvent. The solvent was removed from the soft paraffin wax and filtrate by distillation according to standard practice. The properties of the soft paraffin wax are shown in Table 12.

Table 12

Characteristics of birth k t u p od Example 4 Freezing temperature (° C) 42.1 Oil content (% by weight) 1.7 Viscosity at 100 ° C (mm ² / s) 5.03 Penetration at 25 ^° C, 0.1 mm 39.0 n-alkanes (% by weight) 60.2 Alkanes other than n-alkanes (% by weight) 39.8

Example 5

The initial soft paraffin wax blend was composed of the sweat oils obtained from the redistilled slacks and the sweat oils obtained directly from the de-oiling of slacks from the refined light and medium vacuum fractions. The composition was as follows: 27% by weight. of redistilled petrolatum oil, 11% by weight. of oil III, 6 wt. of oil II, 21 wt. light sweat oil and 35 wt.%. medium sweat oil. The properties of the mixture are shown in Table 13.

The starting mixture was diluted with a 7.5-fold amount of solvent containing 52% by volume, acetone, 4% by volume, methyl ethyl ketone, 43% by volume, toluene and 1% by volume. water. Mixing was done at 116 ^° C in a sealed apparatus, then the solution was cooled to a final crystallization temperature of - 11 ° C, which was also the filtration temperature. The filter cake in a rotary vacuum filter was washed with an equal amount of cold solvent, suspended in twice the amount of solvent at -17 ° C, filtered again and washed with 1.5 times the amount of solvent. The solvent was then removed from the soft paraffin wax and filtrate by distillation according to standard practice. Soft paraffin wax was obtained with a 49% yield calculated on the weight of the starting mixture. Its characteristics are shown in Table 14.

Claims (3)

PATENT CLAIMS A process for producing high penetration and low viscosity paraffin wax, wherein the minimum penetration value at 25 ° C and 0.1 mm is 30 and the maximum viscosity value at 100 ° C is 10 mm / s, redistillating the slack wax mixture and de-oiling the resulting individual of fractions I, II, III and IV to obtain oils swelled when de-oiling I, II, III and IV, characterized in that at least two of the resulting swelled oils are mixed with one another, optionally up to 65% by weight. sweat oil obtained from non-distilled slack waxes, to form a finished mixture containing at least 15% by weight. of the swollen oil IV (petrolatum oil) and this mixture is then de-oily in a manner known per se in the apparatus used for de-oiling slack waxes with a solvent mixture containing ketones and aromatics with a ketone content of not less than 29% by volume. at temperatures not higher than 125 ° C and crystallization takes place at a final cooling temperature not lower than -17 ° C. Production method according to claim 1, characterized in that the solvent containing the filter cake obtained in de-oiling of the swelled oils is re-suspended once or twice in 5.5 to 23.5 parts by volume of cold solvent and / or filtrate, calculated per part by volume. filter cake and then the suspension is filtered and the filter cake obtained is washed. 3. Paraffin wax having a viscosity of 3,2 to 10,0 mnf / s at 100 ° C, a pour point of 42 to 59 ° C, a penetration value at 25 ° C and 0,1 mm between 30 to 170, of an oil content less than 4.2% by weight. and at least 37% by weight. content of alkanes other than n-alkanes, as measured by gas chromatography, characterized in that it is prepared by the production method according to claim 1.