JPH01308481A - Heat transfer oil - Google Patents

Abstract

PURPOSE:To reduce the formation of carbonaceous material when a heat transfer oil is used at high temperature, by incorporating a small amount of a specified hydrogenated oil having a high hydrogen donating capacity at high temperatures into a heat transfer oil consisting mainly of a mineral base oil and/or a synthetic base oil. CONSTITUTION:A hydrocarbon having a boiling point of 50 deg.C or higher, obtained from the equipment for thermal cracking, catalytic cracking or catalytic reforming of petroleum (e.g., cracking residue obtained from the equipment for thermal cracking of naphtha) is hydrogenated with a hydrogen gas in the presence of a hydrogenation catalyst (e.g., nickel oxide) to give a hydrogenated oil having a hydrogen donating capacity at 350 deg.C or above at least three times that of a base oil comprising a mineral base oil and/or a synthetic base oil. 100pts.wt. mineral base oil and/or synthetic base oil (e.g., 1-phenyl-1-xylylethane) is mixed with 0.1-20pts.wt. said hydrogenated oil as essential constituent, and necessary additives, such as an oxidizing agent and an antifoaming agent, thus giving an objective heat transfer oil.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heat transfer oil, and more particularly to a heat transfer oil that produces less carbonaceous material when used at high temperatures.

BACKGROUND OF THE INVENTION Heat transfer oil is most commonly used as a heat transfer medium in indirect heating systems. The required performance of this heat transfer oil is (
1) It has good thermal stability and can withstand long-term use at high temperatures; (2) it has no problems with physical properties such as specific gravity, viscosity, thermal conductivity, and vapor pressure; (3) it is non-toxic; 4) It is non-corrosive.

Currently, purified mineral oil, diphenyl, diphenyl ether, alkylbenzene, alkylnaphthalene, 1-phenyl-1-xylylethane, and the like are widely used as heat transfer oils. However, heat transfer oil is generally used at high temperatures, so when used for a long time, the oil deteriorates and carbonaceous substances are produced, which causes sludge formation. Therefore, the development of heat transfer oil that exhibits less thermal deterioration at high temperatures and does not generate carbonaceous matter is becoming an important issue.

On the other hand, the existence of hydrogen-donating substances has been known for a long time.
It is often used for coal liquefaction, heavy oil cracking, visbreaking, etc. The most typical hydrogen-donating substance is tetralin (tetrahydronaphthalene), which has two or more aromatic rings or an aromatic ring and a five-membered ring.
It is already known that a hydride of a compound having both of

Problems to be Solved by the Invention However, there has been no attempt to apply these hydrogen-donating substances to the prevention of carbonaceous formation when heat transfer oil is used, nor are there any experimental reports for such purpose. The present inventor focused on the fact that the carbonaceous production mechanism in operations that involve a reduction in molecular weight, such as coal liquefaction and heavy oil cracking, and the carbonaceous production mechanism in the use of heat transfer oil, are essentially the same. Through experiments, the present inventors discovered that the presence of a hydrogen-donating substance is effective for carbonaceous production when using medium oil, and have completed the present invention.

An object of the present invention is to provide a heat transfer oil that generates less carbonaceous material during high-temperature use.

Means for Solving the Problems The present invention provides (i) thermal cracking, catalytic cracking or catalytic reforming of petroleum as an essential component for 100 parts by weight of mineral base oil and/or synthetic base oil. A hydrogenated oil 0.1 obtained by hydrogenating hydrocarbons with a boiling point of 250°C or higher obtained from a heating equipment, and having a hydrogen donating property at 350°C or higher that is 3 times or more that of the mineral base oil and/or synthetic base oil. ~
20 parts by weight of heat transfer oil is provided.

Hereinafter, the content of the present invention will be explained in more detail.

As the mineral base oil and the synthetic base oil of the present invention, any oil having a viscosity comparable to that of the oil used as a lubricating oil in the membrane may be used.

Specifically, the mineral base oil includes, for example, 70 pale oil, SAE 10.5AE20.5AE30.5AE
Various grades such as 50 and bright stock are used.

Specific examples of synthetic base oils include polybutene, α-olefin oligomer, alkylbenzene, alkylnaphthalene, diester, polyol ester, polyglycol, polyphenyl ether, tricresyl phosphate, silicone oil, perfluoroalkyl ether, Normal paraffin, diphenylalkane, etc. are used.

Among these, 1-phenyl-1-xylylethane, which is a type of diphenylalkane and is represented by the formula, is particularly preferably used.

In the present invention, the hydrogenated oil added to the base oil must have excellent hydrogen donating properties to the base oil. It must be a substance that donates hydrogen under conditions such that carbonaceous substances or polymeric substances are generated from the base oil at high temperatures. On the other hand, the base oil is selected to have properties that match the use of each heat transfer oil. If too much hydrogenated oil is added to the base oil, the inherent properties of the base oil will be impaired and the performance as a heat transfer oil will be lost. Therefore, it is preferable that the amount of hydrogenated oil added to the base oil is small and effective. From a practical standpoint, the amount of hydrogenated oil added to base oil is 0.1 to 100 parts by weight of base oil.
It is necessary that the amount is 20 parts by weight, preferably 1 to 1
The amount is 5 parts by weight, more preferably 2 to 10 parts by weight. Further, in this case, the hydrogen donating property of the hydrogenated oil added to the base oil needs to be at least 3 times, preferably at least 5 times, more preferably at least 10 times that of the base oil. The present inventor has found that hydrogenated oil obtained by hydrogenating hydrocarbons with a boiling point of 250°C or higher obtained from an apparatus for thermal cracking, catalytic cracking, or catalytic reforming of petroleum is effective as a hydrogenated oil that satisfies the above-mentioned conditions. I discovered that. This hydrogenated oil contains compounds having two or more aromatic rings, an aromatic ring-ring and an unsaturated five-membered ring.
It contains a large amount of compounds having both of

Specifically, the cracked residual oil from naphtha pyrolysis equipment, FCC equipment (
Examples include cycle oil (catalytic cracker), slurry oil and decanted oil (DCO), naphtha catalytic reformer reformed residue, crude oil pyrolysis cracked tar, or mixtures thereof.

It is generally known that base oils also contain the above-mentioned polycyclic aromatic compounds, but the content of compounds with good hydrogen donating properties is extremely small, and it is said that the base oil has extremely low hydrogen donating properties. This has been confirmed through experiments.

Hydrocarbons with a boiling point of 250°C or higher obtained from equipment for thermal cracking, catalytic cracking, or catalytic reforming of this petroleum can be hydrogenated by any method, but usually hydrogen gas is produced in the presence of a catalyst with a hydrogenation function. A method of hydrogenation is used.

The catalyst having a hydrogenation function is not particularly limited, and any known catalyst used for hydrotreating petroleum fractions can be used. Specifically, the sulfide, oxide, etc. of at least one metal element selected from Groups V to II of the periodic table, especially at least one metal element selected from nickel, cobalt, molybdenum, vanadium, and tungsten, is used as alumina. , those supported on inorganic carriers such as silica, silica-alumina, and cation-substituted zeolites, or aromatic ring hydrogenation catalysts such as nickel, nickel oxide, nickel-copper, platinum, platinum oxide, platinum-rhodium, platinum-lithium,
Examples include metals such as rhodium, palladium, cobalt, Raney cobalt, and ruthenium supported on inorganic carriers such as activated carbon, alumina, silica-alumina, diatomaceous earth, and zeolite. The conditions for hydrogenating feedstock oil in the presence of these catalysts having a hydrogenation function are 300%
℃ to 400℃ and 30 atmospheres to 150 atmospheres, and in the case of an aromatic ring hydrogenation catalyst, the temperature is preferably 150℃ to 3
The temperature is preferably 00°C and 30 to 150 atmospheres.

There are no particular restrictions on the reactor, and a hydrogenated oil having good hydrogen-donating properties can be prepared by using a general fixed bed reactor. The thus obtained hydrogenated oil contains hydrogen-donating substances such as dihydronaphthalene, tetrahydronaphthalene, dihydroanthracene, dihydrophenanthrene, tetrahydroacytracene, tetrahydrophenanthrene, octahydroanthracene, and octahydro. These substances include phenanthrene and the like, and although it is possible to use these substances alone, it is not preferred from an economic standpoint.

In the present application, the hydrogen donating properties of these hydrocarbons are evaluated by the following method. This is a method of calculating from the amount of captured migrating hydrogen using a hydrogen acceptor.

That is, a sample and a hydrogen acceptor such as anthracene are reacted under certain conditions, and after the reaction, the amount of hydrogenated hydrogen acceptor is analyzed by chromatography.

Specifically, a predetermined amount of a hydrocarbon sample and anthracene (sample/anthracene-1/2 weight ratio) are placed in an autoclave equipped with a stirrer, and the temperature and pressure are set at 350° C. or higher, for example, from 350° C. to 450° C. 50kg/cd・
g (N2 pressure) and react for 30 minutes without catalyst. 9.10-dihydroanthracene, 1,4.5.8 before and after reaction
-tetrahydroanthracene, 1,2,3.4-tetrahydroanthracene, 1,2,3,4.5,6,7゜8
- Analyze the amount of octahydroanthracene and residual anthracene by gas chromatography. Since the hydrogen used to generate these anthracene hydrides is supplied from hydrocarbons that have hydrogen-donating properties, the amount of hydrogen transferred from these hydrocarbons to anthracene (hydrogen atoms/5 oul: anthracene) is determined. This is measured as hydrogen donating property.

This method is described by Yokono T., Marsh
H, and Yokono M,, Fue l
, 60.607 (1981).

Such a substance can be added to the base oil at the stage of producing the base oil at a refinery, or it can be added by the user at the stage of using the heat transfer oil.

Furthermore, at the stage of producing base oil, it is possible to obtain oil with two or more aromatic rings obtained from equipment for thermal cracking, catalytic cracking, or catalytic reforming of petroleum, or to combine one aromatic ring with one five-membered ring. It is also possible to hydrogenate the oil containing the compound with the base oil to obtain the hydride at the same time as producing the base oil.

Additionally, various additives are added to ordinary heat transfer oil to improve its performance. There is no problem in adding such additives to the heat transfer oil of the present invention. Such additives include, for example, antioxidants, detergent dispersants, viscosity index improvers, pour point depressants, corrosion inhibitors, metal deactivators,
Examples include rust inhibitors, antifoaming agents, and coloring agents. Details of these various additives can be found, for example, in "Lubricant Science Journal, Volume 15, No. 6" or "Petroleum Product Additives" edited by Toshio Sakurai.
(Saiwai Shobo) ° etc. The total amount of these various additives added is preferably 10 parts by weight or less, preferably 5 parts by weight or less, particularly preferably 3 parts by weight or less, based on 100 parts by weight of the base oil.

EXAMPLES The present invention will be explained in more detail by the following experiments, comparative experiments, working examples, and comparative examples.

Experiments 1 to 3, Comparative Experiments 1 to 3 The following experiments were conducted to compare the hydrogen donating properties of heat transfer oil base oil and hydrogenated oil. As the heat transfer oil base oil, 5AEIO, 5AE30.5AE5 from Arabian crude oil is used.
0 (all of which were hydrorefined), naphtha pyrolysis unit cracked residue, naphtha catalytic reformer reformed residue, and FCCCC unit decanted bioilized product were used as examples of hydrogenated oil. The experimental method was as described above.

In other words, the sample and anthracene are reacted under certain conditions,
The amount of hydrogen transferred was calculated from the amount of hydrogen added to anthracene. Said 5AEIO.

5AE30 and 5AE50 base oils were reacted with anthracene under certain conditions (Table 1), and after the reaction, 9,10-dihydroanthracene, 1,2,3,4-tetrahydroanthracene, 1,4,5,8-tetrahydroanthracene and The amount of 1.2,3,4,5°6.7.8-octahydroanthracene was analyzed by gas chromatography. As a result, the amount of hydrogen transferred from each base oil to anthracene can be determined. The results are shown in Table 3. On the other hand, the hydride obtained by hydrogenating naphtha pyrolysis equipment cracked residual oil, naphtha catalytic reformer reformed residual oil, and FCC equipment decanted oil under certain conditions (Table 2) was reacted with anthracene under the conditions shown in Table 1. 9.10-dihydroanthracene, 1.4.5.8
-tetrahydroanthracene, 1,2.3.4-tetrahydroanthracene, 1.2.3,4,5,6,7.8
-The amounts of octahydroanthracene and anthracene were analyzed by gas chromatography. The increase and decrease in these values before and after the reaction was determined, and the amount of hydrogen transferred from the hydride of the naphtha pyrolysis equipment cracked residual oil, the naphtha catalytic reformer reformed residual oil, and the FCC equipment decanted oil to anthracene (hydrogen atom/1 lot anthracene) was determined. I asked for The amount of hydrogen transferred to anthracene from each base oil and the amount of hydrogen transferred to anthracene from the hydrides of naphtha pyrolysis unit cracked oil, naphtha catalytic reformer reformed residue, and FCC unit decanted oil are summarized in the table below. Shown in 3.

As a result, the amount of hydrogen transferred from each base oil is very small.
On the other hand, in the case of hydrogenated oil, the amount of hydrogen transferred is quite large;
In other words, the hydrogen donating property is more than three times that of each base oil, for example, 1
It can be seen that there are 0 to 30 times more.

Table 1. Hydrogen donating experimental conditions table 2. Hydrogenation conditions 3 of naphtha pyrolysis equipment cracked residual oil, naphtha catalytic reformer reformed residual oil, and FCC equipment decanted oil, experimental results of hydrogen transfer amount Example 1, Comparative Example 1 Internal stirring type with internal volume of 100- In Comparative Example 1, the 5AE50 base oil shown in Comparative Experiment 3 was measured using an autoclave experimental apparatus.
In Example 1, 100 parts by weight of the same 5AE50 base oil and 5 parts by weight of the hydride of the naphtha thermal cracker cracked residue shown in Experiment 1 were added to the above autoclave, and 40 parts by weight of the same 5AE50 base oil were added.
Internal stirring was continued for 72 hours at 0°C. The gas phase was pressurized with nitrogen at an initial pressure of 5 kg/cj (at room temperature) and then heated.

After 72 hours, the contents were taken out and the formation of carbonaceous matter was observed, and then the toluene insoluble content was measured. The results are shown in Table 4.

Example 2, Comparative Example 2 In Comparative Example 2, the 5AE30 base oil shown in Comparative Experiment 2 and Example 2 were placed in an internally sealed constant temperature oven (made of stainless steel) shown in the figure.
Now, 100 parts by weight of the same 5AE30 base oil and 7 parts by weight of the hydride of the naphtha catalytic reformer reformed residual oil shown in Experiment 2 were added to each of the above-mentioned internally sealed thermostats. In each case, a nichrome wire with a surface temperature of 800°C was immersed in the liquid, the liquid was stirred, and a constant temperature bath was heated to maintain the temperature of the liquid at 200°C. In addition, the gas phase was replaced with nitrogen.

After this state was continued for 1,500 hours, the liquid was sampled to observe the formation of carbonaceous substances in the liquid, and then toluene insoluble matter was measured. The results are also shown in Table 4.

Table 4 The following points are clear from each of the above embodiments.

(1) The hydrogen donating property of the heat transfer oil base oil is small.

(2) The hydrogen-donating properties of hydrides obtained from petroleum pyrolysis equipment, catalytic cracking equipment, and catalytic reforming equipment are much greater than that of heat transfer oil base oil.

(3) Addition of hydrides of products obtained from the above-mentioned petroleum thermal crackers, catalytic crackers, and catalytic reformers to the heat transfer oil base oil greatly reduces the production of carbonaceous substances.

(4) A large amount of the hydride product obtained from the petroleum pyrolysis equipment, catalytic cracking equipment, and catalytic reforming equipment is not required, and in the above example, a few percent is sufficient to exhibit the effect.

Effects of the Invention As described above, by adding a small amount of a hydrocarbon with a boiling point of 250°C or higher obtained from an apparatus for thermally cracking, catalytic cracking or catalytic reforming of petroleum and having a predetermined hydrogen donating property to heat transfer oil. It can be seen that the precipitation of carbonaceous substances when using the heat transfer oil is restricted, and that it can be used without impairing the properties of the base oil.

[Brief explanation of the drawing]

The figure is a schematic diagram showing a test apparatus used in an example of the present invention. (1) stainless steel constant temperature bath, (2) stirring device, (3
) Nichrome wire, (4): Thermometer. Patent applicant Nippon Oil Co., Ltd.

Claims (1)

[Scope of Claims] [1] (i) As an essential component for 100 parts by weight of mineral base oil and/or synthetic base oil, (ii) An apparatus for thermally cracking, catalytically cracking, or catalytically reforming petroleum. Hydrocarbons with a boiling point of 250°C or higher obtained from
Or hydrogenated oil 0.1 to 2 times more than synthetic base oil
Heat transfer oil containing 0 parts by weight. [2] Hydrocarbons with a boiling point of 250°C or higher obtained from the equipment for thermal cracking, catalytic cracking, or catalytic reforming of the petroleum are used as naphtha pyrolysis equipment cracked residue, FCC equipment (catalytic cracking equipment) cycle oil, slurry oil, and decane. The heat transfer oil according to claim 1, which is ted oil (DCO), naphtha catalytic reformer reformed residual oil, crude oil pyrolysis equipment cracked tar, or a mixture thereof.