JPH03152196A - Removal of soot from lubricant - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION OF THE INVENTION The present invention relates to the removal of soot from lubricating oils for non-gasoline fueled internal combustion engines by contacting the oils with a strong heterogeneous base. Regarding.

(Prior art and problems to be solved by the invention) Non-gasoline fuel internal combustion engines (e.g. diesel engines)
During combustion of the fuel inside, the fuel is injected into the combustion chamber in the form of small droplets, and these droplets undergo a complex combustion process, including pyrolysis. If combustion is complete, the fuel droplets are converted to carbon dioxide and water. However, if combustion is incomplete, the remainder of the fuel droplets often produces soot particles. This is because some incompletely fueled fuel droplets reach the relatively cold cylinder walls where combustion is rapidly reduced and soot particles are produced.

When the piston moves to its uppermost position, the soot particles are covered by a film of lubricating oil. The soot contained in the oil is then scraped into the engine lubricant sump by the piston rings as the piston moves downward through the cylinder.

For many years, dispersants have been used in lubricating oils to suspend soot. This, in turn, reduces the harmful effects of soot on engine wear. However, at this point, the oil's ability to protect the engine becomes limited, even with the most effective dispersants. In addition, soot particles are usually small and finely dispersed,
As a result, currently available filters are generally inadequate at removing soot. Centrifugal filters may remove larger soot particles, but they only partially remove soot from lubricating oils.

It is therefore desirable to have a simple and convenient method that is effective for removing soot from lubricating oils, thereby avoiding the deleterious effects of leaving soot suspended in the oil.

SUMMARY OF THE INVENTION The present invention relates to a method for removing soot from lubricating oil. More specifically, soot can be effectively removed from lubricating oils used in non-gasoline fueled internal combustion engines by contacting the soot with a strong heterogeneous base. The term "heterogeneous" means that the strong base is in a separate (or substantially separate) phase from the lubricating oil, i.e., the strong base is insoluble or substantially insoluble in the oil. . When the soot in the oil comes into contact with a strong base, the soot (which has an acidic surface) reacts with the strong base and becomes fixed to it as a deposit. Thus, soot is removed from the oil. The strong base should be immobilized in some way (eg, in a container or housing) when in contact with the oil to avoid entering or passing along with the oil.

DETAILED DESCRIPTION OF THE INVENTION In the present invention, soot present in lubricating oil is removed by contact with a heterogeneous strong base. A “strong base” is a base or base material (which has an acidic surface) that is
(as used) refers to virtually any base that causes it to be immobilized as a deposit on the base. Examples of suitable strong bases are barium oxide (Bad), calcium hydroxide (C
a (OH)z), magnesium carbonate (Mg CO3)
, magnesium hydroxide (Mg(OH)z), magnesium oxide (MgO), sodium aluminate (NaA I
Ot>, sodium carbonate (Nag CO3), sodium hydroxide (NaOH), zinc oxide (ZnO), or mixtures thereof. Magnesium oxide, sodium hydroxide, zinc oxide or mixtures thereof are preferred, magnesium oxide, sodium hydroxide or mixtures thereof are particularly preferred, and magnesium oxide is most preferred.

The exact amount of strong base required can vary widely depending on the amount of soot in the oil. However, only an effective (or sufficient) amount is used to reduce the soot content of the lubricating oil, which amount is typically from about 0.1 to about 20% by weight, preferably about 0
．． It ranges from 5 to about 10% by weight, most preferably from about 0.5 to about 5% by weight.

If desired, the strong base can be incorporated (e.g., impregnated) into the substrate, where the substrate is placed within the lubrication system of an internal combustion engine (e.g., on top of the engine block or near the sump) or within the lubrication system of the engine. Preferably, the substrate is part of a filter system for filtering oil, which may be located externally, but the substrate may be separate therefrom. The strong base may be chemically bonded to the substrate or physically incorporated into the substrate. Examples of suitable substrates include alumina, activated clay, cellulose, cement binders, silica-alumina, polymer matrices, activated carbon, but
Not limited to these. High surface area substrates such as alumina, cement binders, polymer matrices, and activated carbon are preferred; the substrates may be formed into various shapes such as pellets or spheres. Additionally, the substrate may be inert (but need not be).

The strong base may be incorporated into the substrate by methods known to those skilled in the art. For example, if the substrate were alumina spheres, the strong base may be attached by using the techniques described below.

A highly porous alumina is chosen. The porosity of alumina is measured by weighing a dry aluminum plate and then immersing it in water. The alumina is removed from the water and its surface water is removed by blowing away with dry air. The alumina is then reweighed and the zero weight difference compared to the dry alumina weight is expressed as grams of water per gram of dry alumina. A saturated solution of calcium hydroxide in water is prepared. This solution is then added to the dry alumina in an amount equal to the difference between the weight of wet alumina and the weight of dry alumina. Water was removed from the alumina by heat and Ca(OH) was deposited on the alumina as a product.
) leave z. This preparation can be carried out at ambient conditions, except that the water removal step is carried out above 100°C.

Once the soot has been removed from the oil, the deposit thus produced is fixed as a heterogeneous deposit with the strong base or the strong base on the substrate (if used). Thus,
The soot that remains, usually dispersed in the oil, is then removed as a deposit.

Soot can be present in virtually any lubricating oil used in the lubricating oil system of virtually any non-gasoline fueled internal combustion engine. Thus, "internal combustion engine" as used herein refers to virtually any internal combustion engine other than a gasoline-fueled internal combustion engine. This applies to non-gasoline fueled automotive and trunk engines, two-cycle engines, aviation piston engines, marine and rail engines, gas combustion engines, alcohol (e.g. methanol) powered engines, stationary drive engines.
(nary powered engine), turbine, etc. However, soot is primarily a problem in compression ignition engines such as diesel engines, especially modern design diesel engines with high fuel injection pressures. - The trend in diesel engine design to increase fuel injection pressure to produce smaller fuel droplet sizes
It seems to make the problem worse. - Although smaller fuel droplet sizes do not produce as much particulate emissions, soot formation in the lubricating oil is often increased.

In addition to soot, lubricating oils typically contain a large amount of lubricating oil stock (ie, a lubricating base oil) and a small amount of one or more additives. Lubricating oil raw materials may be derived from natural lubricating oils, synthetic lubricating oils, or mixtures thereof. - Generally, the lubricating oil feedstock has a viscosity in the range of about 5 to about 10.000 C5t at 40°C;
Typical applications require oils with viscosities ranging from about 10 to about 1.000 cSt at 40°C.

Natural lubricating oils include animal oils, vegetable oils (eg, castor oil and lard oil), petroleum oils, mineral oils, and oils derived from coal or shale.

Synthetic oils include polymerized olefins and copolymerized olefins (e.g., polybutylene, polypropylene, propylene-isobutylene copolymer, chlorinated polybutylene, poly(1)
-hexene), poly(l-octene), poly(1-decene), etc. and mixtures thereof) and halo-substituted hydrocarbon oils; alkylbenzenes (e.g. dodecylbenzene, tetradecylbenzene, dinonylbenzene) , di(2-ethylhexyl)benzene, etc.); polyphenyls (e.g., biphenyl, delphenyl, alkylated polyphenyls, etc.); alkylated diphenyl ethers, alkylated diphenyl sulfides, and derivatives, analogs, and the like thereof; Contains homologs; etc.

Synthetic lubricating oils also include alkylene oxide polymers, interpolymers, copolymers, and derivatives thereof, in which the terminal hydroxyl groups have been modified by esterification, etherification, and the like. Synthetic oils of this class include polyoxyalkylene polymers prepared by polymerization of ethylene oxide or propylene oxide; alkyl and aryl ethers of these polyoxyalkylene polymers (e.g. methyl-polyisopropylene glycol ether with an average molecular weight of 1000); ,
diphenyl ether of polyethylene glycol with a molecular weight of 500-1000, diethyl ether of polypropylene glycol with a molecular weight of 1000-1500)
; and these mono- and poly-carboxylic acid esters (
Examples include tetraethylene glycol acetate, mixed C8-C8 fatty acid ester, and cl, oxo acid diester).

Another suitable class of synthetic lubricating oils are dicarboxylic acids (e.g.
Phthalic acid, succinic acid, alkylsuccinic acid and alkenylsuccinic acid, maleic acid, azelaic acid, speric acid, sebacic acid, fumaric acid, adipic acid, lylunic acid dimer, malonic acid, alkylmalonic acid, alkenylmalonic acid, etc. )
and various alcohols (eg, butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol, etc.). Specific examples of these esters are dibutyl adipate, di(2-ethylhexyl) sebacate
, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, 2-ethylhexyl diester of lylunic acid dimer, and 1 mole of sebacic acid. complex ester produced by reacting 2 moles of tetraethylene glycol and 2 moles of 2-ethylhexanoic acid, etc.

In addition, esters useful as synthetic oils include esters made from C2~cog monocarboxylic acids and polyols and polyol ethers, such as evaneopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, etc. Synthetic hydrocarbon oils are also obtained from hydrogenated oligomers of conventional olefins.

Silicone oils (e.g. polyalkyl-, polyaryl-, polyalkoxy-1 or polyaryloxy-
Siloxane oils and silicate oils) constitute another useful class of synthetic lubricating oils. These oils include tetraethyl silicate, tetraisopropyl silicate, tetra-(2
-ethylhexyl) silicate, tetra-(4-methyl-2-ethylhexyl) silicate, tetra(p-t
ert-butylphenyl) silicate, hexa-(4methyl-2-pentoxy)-disiloxane, poly(methyl)-siloxane, poly(methylphenyl)siloxane, and the like. Other synthetic lubricating oils include liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, diethyl ester of decylphosphonic acid), polymerized tetrahydrofurans, poly-alpha-olefins, and the like.

Lubricating oils may be derived from unrefined oils, refined oils, rerefined oils, or mixtures thereof. Unrefined oils are obtained directly from natural or synthetic sources (eg, coal, shale, or tar sands) without further purification or processing. Examples of unrefined oils include shale oils obtained directly from retorting operations, petroleum oils obtained directly from distillation, or ester oils obtained directly from esterification processes, each of which is then processed without further processing. used for. Refined oils are similar to unrefined oils except that they have been treated with one or more refining steps to improve one or more properties. Suitable purification techniques include distillation, hydrotreating, dewaxing, solvent extraction, acid or base extraction, filtration, and leaching, all of which are known to those skilled in the art. Rerefined oils are obtained by processing refined oils in a manner similar to that used to obtain refined oils. These rerefined oils are also known as recycled or reprocessed oils and are often further processed by techniques for the removal of spent additives and oil breakdown products.

The lubricating oil may include one or more additives to produce a well-blended lubricating oil. Such lubricating oil additives include antiwear agents, antioxidants, corrosion inhibitors, detergents, dispersants, pour point depressants, extreme pressure additives, viscosity index improvers, friction modifiers, and the like.

These additives typically include, for example, C, V, Smalbeer and R, Kennedy Sm1th, “Lubrica
nt Additives (additives for lubricants)”19
67, pp. 1-11 and U.S. Pat. No. 4,105,571, the disclosures of which are incorporated herein by reference. Typically, there will be from about 1 to about 20 weight percent of these additives in a fully formulated engine lubricating oil. However, the exact additives used (and their relative amounts) will depend on the particular use of the oil.

The present invention also relates to European Patent Application No. 88300090.3.
(Publication No. 0275148, published July 20, 1988).

The disclosure of that patent is incorporated herein by reference.

For example, the polynuclear aromatic hydrocarbons normally present in the lubricating oils used (in particular P
NA) may be substantially removed (eg, from about 40 to about 90% or more removed) by passing the oil through a sorbent volume. The sorbent may be immobilized at or remote from the substrate, and the sorbent may also be the substrate to which the strong base is immobilized. Preferably, the substrate and sorbent are placed in the lubrication system of an internal combustion engine where the oil needs to be circulated after it is used to lubricate the engine. Most preferably, the substrate and sorbent are part of an engine filter system for filtering oil. In this case, the sorbent is placed on top of the engine block or near the sump, preferably downstream of the oil (i.e. after the oil has been heated) as the oil circulates through the engine. It is convenient. Most preferably, the sorbent is downstream of the substrate.

Suitable sorbents include activated carbon, attapulgas clay silica gel, molequinylar sheep, dolomite clay, alumina, zeolites, or mixtures thereof. Activated carbon is preferred. (1) it is at least partially selective for the removal of polynuclear aromatic compounds containing more than three aromatic rings, and (2) the removed PNA is tightly bound to the activated carbon and after disposal. Free PN without leaching
A is not possible because (3) the removed PNA is not redissolved in the lubricating oil used, and (4) heavy metals such as lead and chromium can be removed as well. Although most activated carbons remove PNA to some extent, wood- and beet-based activated carbons are significantly more effective at removing aromatics of four or more rings than coal- or coconut-based activated carbons. .

The amount of sorbent required depends on the PNA concentration in the lubricating oil. Typically, for 5 quarts of oil, about 20
~150 g of activated carbon can reduce the PNA content of the lubricating oil used by up to 90%. The lubricating oil used typically contains from about 10 to about 10.000 ppm PNA.

It may be necessary to provide a container to hold the sorbent, such as a circular mass of sorbent supported on a fine wire mesh. The oil filter may also include a sorbent that can be combined with the polynuclear aromatic hydrocarbons held in the pockets of the filter paper. These features can also be applied to the substrates described above.

Any of the above embodiments of the invention may also be mixed with, coated with, or coated with additives normally present in lubricating oils, particularly engine lubricating oils.
or impregnated sorbents (e.g. sorbents as described above)
(European Patent Application No. 883000)
90.3). In this embodiment, additives (eg, the lubricating oil additives described above) are gradually released into the lubricating oil to replenish the additives as they are depleted during use of the oil. The ease with which additives are released into the oil depends on the nature of the additive and sorbent. However, it is preferred that the additive be completely released within 150 hours of engine operation. Additionally, the sorbent may include from about 50 to about 100 weight percent additive (based on the weight of the activated carbon), which generally corresponds to 0.5 to 1.0 weight percent additive in the lubricating oil. do.

Thus, the present invention can be combined with removing PNA from lubricating oils, enhancing the performance of lubricating oils by releasing conventional additives into the oil, or both. In these embodiments, the substrate (if used) and the sorbent may include the same material.

Although the present invention has been described above with particular reference to lubricating oils used in non-gasoline fueled internal combustion engines, the present invention can be suitably applied to virtually any oil containing soot (e.g., industrial lubricating oils). .

Hereinafter, the present invention will be explained in more detail with reference to the following examples. These examples are not intended to limit the scope of the claims.

In these examples, the amount of soot in the oil samples was determined by thermogravimetric analysis (referred to as TGA). TGA is an analytical technique in which an oil sample suspended in the arm of a thermobalance is heated and held within a constant temperature zone of a furnace through which a controlled atmosphere is passed. Loss or gain of sample weight
Measured as a function of the temperature program applied to the furnace. The composition of the gas flowing through the furnace can be changed during the test operation. TG^ operation is by McGeeh
An) and Fontana ("Effect of soot on piston deposits and crankcase oil").
on PistonDeposit and Cr
Ankcase 0ils) - Infrared spectroscopy techniques for the analysis of soot”, SAE paper, 801368.198
1 year). Other TGA methods are described in ASTM E 1131, Standard Test Methods for Thermogravimetric Composition Analysis.

However, the TGA operation used in the examples below was
Temperature and gas profiles different from those in the two documents mentioned above are used as follows. Temperature N! The temperature was increased from 25°C (room temperature) to 600°C at a rate of 20°C/min in an atmosphere. At 600°C, switch the atmosphere to air, maintain that temperature for 5 minutes, then increase to 20°C.
The temperature was increased to 680°C at a rate of 1/min. Air is N! The total weight loss after replacing is considered fixed carbon. As used herein, soot refers to the amount of pyrolyzable hydrocarbons and fixed carbon.

Great training - Kamiichi Soot removal mag using NaOH on activated carbon (Ma
ck) Using a working oil from a T7 engine test, the ability of a strong base to reduce the viscosity of a working oil by removing soot from the oil was demonstrated. The viscosity of the oil used before treatment with strong base was 26.6 centistokes at 100°C and 257.5 centistokes at 40°C. In this example, 2,000 g of the oil used was placed in a filter containing 170 g of NaOH on an activated carbon base.
It was circulated at a rate of d/min. After 8 hours, the viscosity of the oil is io
17.7 centistokes at o'c and at 40°C
It was 145.6 centistokes. Improved TG above
Using Procedure A, the amount of soot in the oil before and after contact with NaOH on the activated carbon was measured to be 20.6% and 10.7%, respectively, which is 48.1% of the soot. This corresponds to a decrease in The results obtained from this example are summarized in Table 1 below.

Removal of soot using ZnO on alumina 2.000 g of Mack T7 oil used from Example 1 was added to 2.000 m in a filter containing 192 g of Zn0 on alumina substrate.
It circulated at a speed of /min. After 8 hours, the viscosity of the oil is 100
22.3 centistokes at ℃ and 149 at 40℃
．． It was 0 centistokes. The amount of soot before and after contact with ZnO on alumina is 20.5% and 9.4%, respectively.
%Met. This corresponds to a 54.1% reduction in soot. The results obtained from this example are also summarized in Table 1 below.

Table 25-200 Water + 1 Volatile 200-400 Oil feedstock 400-600 Pyrolyzable hydrocarbon 600-68
0 Fixed carbon residue Total ash soot (400-680℃) Soot reduction rate (%) Viscosity @100℃, cSt @40℃, cSt Before After Before After 1.31.41.10,8 77.885.876 .187.8 16.67, 216.85.9 4.03.53.73.5 0.42.22.32.0 20.610.720.59.4 48.1 54.1 26.617, 726.622.3 257.5145.6257.5149.0 The data in Table 1 shows that the untreated used oil (in the "before" column) has an appreciable amount of soot (pyrolyzable hydrocarbons and fixed carbon). to have,
and that contact with a substrate containing a strong base significantly reduces the amount of soot in the oil (see "After" column). The data in Table 1 also show that the reduction in soot corresponds to a significant reduction in viscosity.

■Display of incident 2. Name of the invention Correct, calligraphy (method) %formula% How to remove soot from lubricating oil 3. Person who makes corrections Relationship with the incident 幀人 4, generation

Claims (25)

[Claims] (1) A method for removing soot from a lubricating oil used in a non-gasoline fueled internal combustion engine, the method comprising: contact with a heterogeneous strong base over a period of time, the strong base being barium oxide,
A method for removing soot as described above, characterized in that it is calcium hydroxide, magnesium carbonate, magnesium hydroxide, magnesium oxide, sodium aluminate, sodium carbonate, sodium hydroxide, zinc oxide, or a mixture thereof. 2. The method of claim 1, wherein the strong base is magnesium oxide, zinc oxide, sodium hydroxide, or a mixture thereof. (3) Strong base is magnesium oxide, sodium hydroxide,
or a mixture thereof. The method according to claim 2. (4) The method according to claim 3, wherein the strong base is magnesium oxide. 5. The method of claim 1, wherein the heterogeneous strong base is incorporated into the substrate. 6. The method of claim 5, wherein the substrate is alumina, activated clay, cellulose, cement binder, silica-alumina, polymer matrix, activated carbon, or mixtures thereof. (7) The method according to claim 5, wherein the base material is activated carbon. 8. The method of claim 5, wherein the substrate is part of an oil filter system of a non-gasoline fueled internal combustion engine. (9) A method for removing soot from lubricating oil circulating within the lubrication system of an internal combustion engine, the method comprising: (a) circulating the soot-containing lubricating oil through a heterogeneous strong base fixed within the lubrication system of the engine; , and then (b) contacting the soot with a heterogeneous strong base for a period sufficient to fix at least a portion of the soot with the heterogeneous strong base, the strong base being barium oxide, calcium hydroxide, etc. ,
A method for removing soot as described above, characterized in that it is magnesium carbonate, magnesium hydroxide, magnesium oxide, sodium aluminate, sodium carbonate, sodium hydroxide, zinc oxide, or a mixture thereof. (10) Claim 9, wherein the strong base is magnesium oxide, zinc oxide, sodium hydroxide, or a mixture thereof.
Method described. (11) The method according to claim 10, wherein the strong base is magnesium oxide, sodium hydroxide, or a mixture thereof. (12) Claim 11, wherein the strong base is magnesium oxide.
Method described. (13) Claim 9, wherein the heterogeneous strong base is incorporated into the substrate.
Method described. (14) Claim 13, wherein the base material is alumina, activated clay, cellulose, cement binder, silica-alumina, polymer matrix, activated carbon, or a mixture thereof.
Method described. (15) The method according to claim 14, wherein the base material is activated carbon. 16. The method of claim 13, wherein the substrate is part of an engine oil filter system. 17. The method of claim 9, wherein the polynuclear aromatic compound is also removed from the lubricating oil by contacting the oil with a sorbent disposed within the lubricating system. 18. The method of claim 17, wherein the sorbent and the heterogeneous strong base are included within an engine oil filter system. (19) Claim 1, wherein the heterogeneous strong base is incorporated into the substrate.
8. The method described in 8. (20) Claim 19, wherein the sorbent and the substrate contain the same substance.
Method described. (21) The method of claim 20, wherein the sorbent and the substrate include activated carbon. 22. The method of claim 17, wherein the sorbent is impregnated with at least one engine lubricant additive. 23. The method of claim 22, wherein the lubricating oil additive is an antiwear, antioxidant, friction modifier, or a mixture thereof. (24) The method of claim 23, wherein the sorbent comprises activated carbon. (25) The method according to claim 9, wherein the internal combustion engine is a diesel engine.