JPH04233996A - Low-pour-point high-vi lubricating oil prepared by dewaxing with common solvent - Google Patents

Abstract

PURPOSE: To obtain a low-pour-point high-boiling high-viscosity index dewaxed oil in high yield by mixing a low-boiling conventional VI wax-containing oil with a high boiling VI oil and dewaxing the mixture by co-treatment under usual dewaxing conditions using a lowly miscible dewaxing solvent.

CONSTITUTION: A low-boiling conventional VI wax-containing oil having a viscosity (100°C) of 3-7 cSt, a 90% off-point lower than that of a high-boiling VI oil by 0-300°C and a VI of below 110 is mixed with a high-boiling high-VI oil having a viscosity (100°C) of 8-10 cSt, a mid LV% boiling point of 475-525°C and a VI of 140 or above, and the mixture is subjected to solvent dewaxing by co-treatment under usual miscible solvent dewaxing using a lowly miscible dewaxing solvent (e.g. methyl ethyl ketone) to obtain a high-boiling high- viscosity index dewaxed oil having a pour point of at least -21°C.

COPYRIGHT: (C)1992,JPO

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION Waxy lubricating oils have been known for a long time. It has also been found that lighter oils, low boiling point and VI oils of about 90-105/110, are more miscible in a dewaxing solvent of a given composition than high boiling point-high VI oils. It is also widely accepted that good yields of dewaxed oil are obtained when the dewaxing operation is carried out under oil/solvent miscible conditions. Therefore, the conditions of solvent to oil ratio, dewaxing temperature and solvent/co-solvent ratio were adjusted to achieve oil-solvent miscibility at the dewaxing temperature (filter temperature). However, very often a compromise has to be made between yield and pour point of the dewaxed oil, i.e. low pour point is achieved at the expense of product yield, or conversely, high yield is sacrificed to high pour point. It can be obtained by removing.

US Pat. No. 3,365,390 describes hydrocracking a heavy oil feed, separating the hydrocracked wax from the hydrocracked lubricating portion of the product, and using an active reforming catalyst to convert hydrogen into hydrogen. A lubricating oil production process is described that includes hydroisomerizing a chemically cracked wax. The isomerized lube oil fraction so produced can be separately dewaxed to recover an ultra-high VI isomerized lube oil, or the isomerized lube oil fraction can be converted into a hydrocracked lube oil fraction. It is dewaxed with a mixture of When the isomerate is dewaxed in combination with the hydrocracked lube oil fraction, the wax recovered is a mixture of hydrocracked and isomerized wax, and the nature of the recovered lube oil is similar to that of the isomerate. The rate is improved due to the presence of the lubricant part.

It is difficult to dewax high boiling high VI wax isomerate and naturally waxy oil fractions to achieve pour points in the region of about -20°C and below. When solvent winterizing such oils at low temperatures, oil/solvent miscibility problems are typically encountered, resulting in poor dewaxed oil yields.

0004

SUMMARY OF THE INVENTION Low miscibility dewaxing solvents such as C3 to C6
When using ketone-based dewaxing solvents such as methyl ethyl ketone, methyl isobutyl ketone, acetone, etc., and mixtures thereof such as MEK/MIBK, significant amounts of low boiling conventional VI containing wax oils can be converted to high boiling high VI It has been found that high boiling high VI oils can be solvent winterized to low pour points under miscible conditions by mixing with oil and co-processing the mixture under common solvent winterization conditions. High boiling height V
The addition of a low boiling conventional VI-containing wax oil to the I oil allows the dewaxing to be carried out under miscible conditions to produce acceptable yields of low pour point dewaxed oils. Furthermore, the low pour point dewaxed oil mixture can then be substantially fractionated into fractions whose specifications are very close to the parent material in terms of boiling point and VI, and that both such fractions have a low pour point of the mixture. was found. When normalizing the yields, it is observed that the yield of the low fluidity-high boiling-high VI oil fraction achieved by the co-processing operation is higher than that achieved when dewaxing the high boiling high VI oil alone. It was done.

[0005]

[Detailed explanation]

Heavy, high boiling high VI containing waxy oils are used when it is a waxy oil obtained by wax isomerization or a conventional oil such as a deasphalted 600N hydrocracked oil or when a low pour point of about 21°C is desired. Typical low-miscibility dewaxing solvents, such as bright stocks, which are immiscible in C3 to C6 ketones at low dewaxing temperatures, add significant amounts of low-boiling to heavy, high-boiling, high-VI-containing wax oils. Conventional V
I-containing waxy oil fraction is added and the mixture is processed through a solvent dewaxing step under miscible conditions to remove common solvents under miscible conditions (e.g., flow/
Solvent desorption to a target pour point of about -21°C and below, preferably about -24°C, most preferably about -27°C, using a filtration temperature not lower than about -35°C such that the filtration ΔT is not less than about -35°C. You can wax.

The light, low-boiling conventional VI-containing waxy oil added to the heavy, high-boiling, high-VI-containing waxy oil is such that it can be easily separated from the heavy oil by distillation; Approximately 50 to 30 points from 10% off points
It is characterized by having a 90% off point of 0°F, preferably 50-100°F. Light oil mass is substantially lighter and has a lower boiling point than heavy oil mass.

The light oil is mixed into a low miscibility dewaxing solvent used at a filtration temperature that provides the waxy oil with a pour point of at least -21°C, preferably about -24°C, and most preferably about -27°C. added to heavy oils in sufficient quantities to make them miscible. The amount of light oil added can be in the range of about 5-50%, preferably 20-40% by volume of the oil mixture.

Solvent dewaxing processes that are advantageous by operating with binary wax feedstocks include dilution indirect chilling, predilution direct chilling, or just direct chilling. Typical solvent dewaxing methods, including those identified as The indirect chilling method is
For example, a waxy oil charge is diluted with a solvent to produce a solution that is passed through a scraped surface chiller where the refrigerant is passed through the outer jacket of the heat exchanger and rotating scraper blades prevent wax buildup on the internal surfaces of the chiller. Includes scraped surface chilling methods.

[0009] Direct chilling methods can use undiluted or prediluted waxy charges. The diluted or undiluted waxy charge is then cooled by injecting a cold solvent directly into the waxy charge. A preferred embodiment of dilution chilling is the DILCHILL process in which the waxy charge is passed through a cooling tower divided into stages and the cold solvent is injected into a number of said stages. A high level of agitation is maintained during those stages where the cold solvent is injected;
Substantially instantaneous mixing of the cooling solvent and waxy oil is achieved, thereby avoiding undesirable impact chilling. This operation is described in more detail in US Pat. No. 3,773,650. In another embodiment, the waxy oil is cooled in the apparatus to about 35° F. above the filtration temperature, with cooling to the filtration temperature occurring in a subsequent scraped surface chiller. This aspect is described in U.S. Pat. No. 3,775,288.
It is listed in the issue.

[0010] Typically used in solvent dewaxing processes,
The same solvents used in the process of the invention, low miscible dewaxing solvents include C3 to C6 compounds such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (
MIBK) and mixtures thereof e.g. MEK/MIBK
is included. Heavy, high-boiling, high-VI-containing wax oils can be either synthetic waxes, such as those obtained from Fischer-Tropsch synthesis, or natural waxes, usually referred to as coarse waxes, such as those obtained from the dewaxing of hydrocarbon oils. It can be a material obtained by isomerization or a natural petroleum material such as hydrocracked oil, deasphalted 600N or bright stock oil. When the waxy oil to be dewaxed is a heavy, high boiling, high VI wax isomerate, the lubricating oil boiling range (i.e. about 330°C
370° C. and above, preferably about 370° C. and above) is the feed to the dewaxing process of the present invention, i.e., a light oil distillate is added to facilitate dewaxing under miscible conditions. It is preferable to utilize the addition of 50%. In general, heavy-high-boiling-high-VI materials, whether they are isomerate natural oils or hydrocracked oils, are 6 to 12 cSt
Viscosity within the range of @100°C, preferably 8-10 cSt @100°C, 450-550°C, preferably 475-5
A material having a mid-LV% boiling point of 25° C. and a VI of at least 120, preferably at least 140. Light, low boiling, low VI oils have a viscosity of about 3-7 cSt @100°C, preferably about 4-6 cSt @100°C, 10
% off point about 0-300°F preferably about 50
A 90% off point of ~100° F. and a VI of less than about 110, preferably less than about 100.

In the process of the present invention, heavy oil is mixed with a significant amount of light oil and solvent dewaxed under miscible conditions at a filtration temperature low enough to yield an oil with a pour point of at least -21°C. allowed to drive law. After processing the blended oil feed by solvent winterization, the resulting dewaxed oil product is very similar to the original parent materials (i.e., conventional VI light oil fraction and high VI heavy oil fraction). It is fractionated into fractions that are close to each other. each of these fractions has a pour point of at least about -21°C, the pour point of the mixture;
has. The yield of -21°C flowing heavy oil obtained by this co-processing method is higher than can be achieved by processing the heavy oil alone.

The wax to be isomerized can be derived from many sources. Synthetic waxes from the Fischer-Tropsch process can be used, as well as waxes recovered from solvent or autorefrigerative dewaxing of common hydrocarbon oils, as well as mixtures of these waxes. The wax from the dewaxing of common hydrocarbon oils is usually referred to as coarse wax and usually contains a significant amount of oil. The oil content of these coarse waxes is 0-45% or more, usually 5-45% or more.
It can be in the range of 30% oil. For this application, heavy wax recovered from brightstock dewaxing and heavy Fischer-Tropsch wax are the feeds of choice.

Hydroisomerization is carried out using hydrogenated metals selected from groups VIB and VIII and mixtures thereof, preferably V
It can be carried out over standard hydroisomerization catalysts containing Group III metals, more preferably noble Group VIII metals, and most preferably platinum. The metal loading is between 0.1 and 5.0% metal by weight, preferably 0.
1-1.0 wt% metal, more preferably 0.2-0.6
Within the weight percent metal range.

The metal hydride component is supported on a refractory inorganic metal oxide support, preferably alumina or silica-alumina, most preferably a transition alumina such as gamma alumina. Preferably the carrier is halogenated. The halogen is usually chlorine or fluorine or a mixture thereof, preferably fluorine, with a net halogen content of 1 to 10% by weight;
Preferably it is within the range of 2 to 8% by weight.

The isomerization is carried out at a temperature of about 250-400°C, preferably 270-360°C, 500-3000 psi H
2, preferably a pressure of 1000-1500 psi H2, a hydrogen gas rate of 1000-10,000 SCF/bbl, 0.1-10 v/v/hr, preferably 1-2
It is carried out under conditions of space velocities in the range v/v/h. Preferred catalysts include U.S. Pat. No. 4,959,337;
U.S. Patent No. 4,906,601 and U.S. Patent No. 4,9
This is the subject of No. 00,700.

The use of these catalysts for the production of lubricant base oils or blending stocks by wax isomerization is described in US Pat. No. 4,929,795, US Pat.
No. 23,588 and U.S. Pat. No. 4,937,399, respectively. The most preferred catalyst is the subject of US Pat. No. 4,906,601. The use of that catalyst for wax isomerization is the subject of US Pat. No. 4,923,588.

The catalyst comprises a noble Group VIII metal on a low fluoride content, small particle size refractory metal oxide base. Catalyst is 0
．． Less than 1-2% by weight, preferably 0.1-1.5% by weight
, more preferably a fluoride content in the range of 0.2 to 1.0% by weight, a particle size of less than 1/16 inch, and a particle size of less than 1/16 inch.
Characterized by having a noble group VIII metal loading in the range of 0% by weight. A preferred small particle support is 1/20 inch trilobe alumina.

As expected, noble metal isomerization catalysts are highly susceptible to deactivation by the presence of heteroatomic compounds (ie, N, O or S compounds) in the wax feed, and therefore, such heteroatomic materials are not included in the wax feed. Care must be taken to remove it from the charge. Such precautions may not be necessary when processing high purity waxes, such as synthetic Fischer-Tropsch waxes. In such cases, subjecting such waxes to a very mild hydrotreatment may be sufficient to guarantee protection against the isomerization catalyst. On the other hand, waxes obtained from natural petroleum feedstocks contain significant amounts of oils containing large amounts of heteroatoms as well as heteroatom compounds. In such cases, the coarse wax should be hydrotreated to reduce the concentration of heteroatomic compounds to a concentration commonly accepted as acceptable for feeds exposed to isomerization catalysts in industry. Such concentrations are typically about 1-5 ppm
and an S content of about 1 to 20 ppm, preferably 2 ppm or less nitrogen and 5 ppm or less sulfur. Similarly, such loose waxes should be deoiled to an oil content in the range of 0 to 35% oil, preferably 5 to 25% oil, prior to hydrotreating. The hydrotreating step is carried out using typical hydrotreating catalysts such as Co/M on alumina.
o or Ni/Mo under standard commercially acceptable conditions, e.g.
v/v/hour space velocity, 500-3000 psigH2
and a hydrogen gas rate of 500-5000 SCF/bbl.

The invention will be better understood by reference to the following non-limiting examples. Figure 1 shows 550-5
Fischer-Tropsch 8 boiling within 75°C
．． It shows that the miscibility of the 7 cSt @100°C isomerate fraction (approximately equivalent to the 250N viscosity grade) can be improved by about 10°C with the addition of about 33% of conventional 150N base oil. Filtration studies were conducted with this mixed feed and compared to a base example evaluation of Nied-Fischer-Tropsch 8.7 cSt @100°C wax isomerate. The isomerate was produced over an isomerization catalyst containing 0.6Pt/5.6% F/Al2O3 with a Fischer-Tropsch 150 wax as a feed at a temperature of 365-375°C, a pressure of 100 psig, a H2 flow rate of 7500 SCF H2/bbl, and 1 was produced by isomerization with LHSV. Dewaxing data is shown in Table 1.

[0020]

[Table 1]

[0021] In an attempt to reach the -21°C flow target,
The solvent composition of the MEK/MIBK system was reduced to 10% MEK and 100% Fischer-Tropsch 8.7 cSt
Dewaxing of the @100°C wax isomerate was carried out at a filtration temperature just below miscibility (-3 degrees from miscibility). With typical immiscible dewaxing, the process provided a low flow filtration temperature range and high filtration rate. However, as commonly experienced in immiscible dewaxing, the cleaning efficiency in two liquid phases is very poor and the resulting low yield of 15.7% by weight is unacceptable. Although not directly measured, it is calculated based on typical immiscible isomerate dewaxing data that the product had a VI of 158, a viscosity at 100°C of about 8.0 cSt. It was observed that when going from miscible to immiscible dewaxing, a decrease in viscosity is common, but the VI shows very little change.

By increasing the filtration temperature, proceeding to miscible dewaxing, as was done in the second example, the yield rose to an acceptable level, but the pour point reached only rose to -10°C. Ta. Using a blend of conventional 150N oil and Fischer-Tropsch 8.7 cSt @100° C. wax isomerate, the filtration temperature can be lowered below the target flow without creating incompatibility. Low flow (-21°C) was achieved with good yields. 600
The plant that processes the N stock is typically 4-6 m3
The low filtration rate of 5.2 m3/m2d is not necessarily the cause of the problem since the filtration rate is designed for a filtration rate of 5.2 m3/m2d and the technology to handle these rates is known.

As can be expected, the product from dewaxing is a mixture of conventional and non-conventional lubricating oils. Important to the process is good separation of light winterized oils from heavy winterized oils, for example light conventional oils from heavy isomerate oils. Although any separation method (distillation, extraction, membrane, etc.) can be considered,
The simplest and easiest method is distillation. For that reason, low boiling conventional lubricating oils are co-processed with relatively high boiling isomerate oils. It is important to recognize that this does not imply wide differences in viscosity grades. Due to the highly paraffinic nature of isomerate oil, it has a much higher boiling point than isoviscosity conventional stocks. This difference in viscosity/boiling point relationship is 5.0 cSt 150N
Separation of the oil and the 8.7 cSt Fischer-Tropsch wax isomerate is quite easy as shown in Table 2.

[0024]

[Table 2]

[0025]

[Table 3]

The dewaxed oil products from the co-processing were cut into fractions, which were then reblended to approximately the same specifications possessed by the individually treated dewaxed oil fractions (
(See Table 2). 9.2 cS using 40% to end point blend
t, 148 VI, -22 °C flow product was made, 102
A VI, 4.7 cSt, -22°C flowing conventional stock was left. These specifications are very close to the parent material. Surprisingly, the dewaxing operation of heavy oil/light oil blends not only makes it easier to dewax heavy oil fractions;
It was also observed that the yield of dewaxed heavy oil was high. Therefore, 100 barrels of Fischer-Tropsch isomerate were dewaxed to 15.7 barrels of -21°C fluid oil (15.
7LV%, see Table 1).
This same 10 of Fischer-Tropsch isomerates
Mixing 0 barrels with 50 barrels of 150N oil (giving a total of 150 barrels of oil to be dewaxed) gives a total dewaxed oil yield of 49.3% (74 barrels DWO based on the 150 barrel mixture); The fractionation yields 60% or 44.4 barrels (60% of 74 barrels) of an oil with a VI, viscosity, and flow equivalent to the 15.7 barrels obtained when the Fischer-Tropsch isomerate is dewaxed alone. It is recognized that it constitutes a quantity. Thus, the yield of premium quality high VI oil is increased and at the same time dewaxing is facilitated (see Figure 2).

This yield increase is much greater than that obtained from simple mixing of separately dewaxed FT isomerate and 150N oil fractions. Linear blending of such fractions to give a final product with a VI of 84LV
A mixture of %FT isomerate/16LV% 150N would be required. This blend is only 18.7% compared to about 44% of the 148VI product obtained by co-processing.
will yield a yield of The oil products obtained by line blending will also be of different quality. Co-processing is 148
VI, 55.21cSt @40℃, 9.19cSt
@100°C giving a 44.4% yield of material, whereas the line blend gave 148 VI, 44.78 cSt @40°C,
7.9 cSt @100°C would result in an 18.7% yield of product. Furthermore, when co-processed and then separated, 102
It yields a light oil of VI and 5 Vis, which is clearly superior to the base 150N oil fraction, which yields a DWO of 90 VI and 5 Vis when dewaxed separately.

[Brief explanation of the drawing]

FIG. 1 shows the miscibility of heavy, high-boiling, high-VI waxy isomerate oils in different proportions of ketone dewaxing solvents at different temperatures, as compared to mixtures of said heavy and light oils in a 2/1 ratio. This is a graph comparing the miscibility of

[Figure 2] Neat Fischer-Tropsch isomerate and Fischer-Tropsch isomerate/150N
FIG. 3 shows the yield of −21° C. fluid dewaxed oil obtained from Fischer-Tropsch isomerate normalized to 100 barrels of Fischer-Tropsch isomerate feed to the dewaxer based on both blends.

Claims (9)

[Claims] 1. Mixing a low boiling conventional VI-containing wax oil with a high boiling high VI oil and co-processing the mixture under conventional miscible solvent winterization conditions with a low miscibility winterization solvent. A method for producing a high boiling high viscosity index dewaxed oil having a pour point of at least -21°C by solvent dewaxing under miscible conditions using a low miscible dewaxing solvent. 2. The high VI oil is a natural petroleum hydrocracked oil or an oil obtained by wax isomerization, and the oil has a
cSt @ viscosity within the range of 100℃, 450-550℃
2. The method of claim 1, having a mid-LV% boiling point of , and a VI of at least about 120. 3. The low-boiling conventional VI-containing wax oil has a viscosity of about 3 to 7 cSt @100°C, and the high-boiling high VI oil has a viscosity of about 3 to 7 cSt @100°C.
Claim 1 having a 90% off point about 0 to 300 degrees Fahrenheit below the 0% off point and a VI of less than about 110.
The method described in. 4. The method of claim 1, 2 or 3, wherein the amount of low boiling conventional VI oil added to the high boiling high VI oil is in the range of about 5-50% by volume. Claim 5: High boiling high VI oil is 8 to 10 cSt @1
Viscosity within the range of 00℃, mid LV of 475-525℃
% boiling point and a VI of at least 140. [Claim 6] The low boiling conventional VI oil is about 4~
5. The process of claim 4, having a viscosity of 6 cSt @100<0>C, a 90% off point about 50-100<0>F below the 10% off point of a high boiling high VI oil, and a VI of less than about 100. [Claim 7] The low boiling conventional VI oil is about 4 to
6. The method of claim 5, having a viscosity of 6 cSt @100<0>C, a 90% off point about 50-100<0>F below the 10% off point of a high boiling high VI oil, and a VI of less than about 100. 8. The method of claim 1, 2 or 3, wherein the amount of low boiling conventional VI oil added to the high boiling high VI oil is in the range of about 20-40% by volume. 9. The low miscibility dewaxing solvent is C3 to C6.
Claim 1, 2 or 3 which is a ketone and a mixture thereof.
The method described in.