JPH0329269B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a composition that improves the ignitability of light oil or heavy oil with a low cetane number, and particularly to a fuel composition that allows a diesel engine to be operated satisfactorily without knocking. Conventional technology Light oil and heavy oil used as fuel for diesel engines in trucks, ships, passenger cars, etc. are produced using straight-run gas oil fraction (hereinafter abbreviated as GO) separated by distillation of crude oil.
The distillate produced by desulfurizing and refining (DS-GO)
). Therefore, the cetane number of these DS-GOs is usually 46 to 60 without special treatment.
It has a certain degree. On the other hand, the light oil fraction produced as a by-product in heavy oil catalytic cracking equipment contains many aromatic hydrocarbons and unsaturated hydrocarbons and has a cetane number that is too low, making it undesirable as a diesel fuel. The same applies to light oil fractions produced by coal liquefaction processes. Furthermore, in recent years, the use of methanol as a diesel fuel has been considered, but there are problems similar to those mentioned above. If the cetane number of these light oil fractions can be improved economically, it will be possible to mix them into DS-GO and the like and use them as diesel fuel, thereby expanding the uses of these light oil fractions. Conventionally, it has been known to add a cetane number improver as a means of improving the cetane number of fuel oil.
It is expensive and therefore impractical. Incidentally, US Pat. No. 4,330,304 discloses that nitroparaffin, kyumene hydroperoxide, and propylene oxide are added in order to improve the combustion efficiency of not only light oil but also heating fuel, that is, to improve combustion efficiency and suppress smoke generation. However, there is no teaching on the effect of improving the cetane number of the fuel itself. Regarding this point, combustion in a diesel engine is instantaneous ignition due to rapid adiabatic compression by the piston, but in furnace combustion, ignition is steady and continuous by the flame in the furnace, so the heating fuel described above It should be noted that the concept of cetane number is not required. In general, light oil used as fuel for conventional diesel engines is a petroleum fraction with a boiling point range of about 200 to 350 degrees Celsius, and has a composition of about 20 to 350 degrees Celsius of aliphatic saturated hydrocarbons.
45 wt%, about 10-30 wt% naphthenic hydrocarbons, and the balance consists of unsaturated and aromatic hydrocarbons. Furthermore, among the aliphatic saturated hydrocarbons mentioned above, linear ones (hereinafter referred to as n-paraffin or normal paraffin) account for about 16 to 25 wt% in light oil, and the hydrocarbon number distribution is Generally, the content is distributed between 9 and 25, and each content is normally distributed. For example, in a type of DS-GO separated from Middle Eastern crude oil, n-C ₉ 0.4wt%, n-C ₁₀ 0.7wt%, n-
C ₁₁ 2.5wt%, n-C ₁₂ 5.0wt%, n-C ₁₃ 6.4wt%,
n-C ₁₄ 4.5wt%, n-C ₁₅ 2.4wt%, n-C ₁₆ 0.9wt
%, n-C ₁₇ 0.4wt%, n-C ₁₈ 0.2wt%, and n-
C ₁₉ 0.1wt% (n-C ₉ refers to n-paraffin with 9 carbon atoms. The same applies hereinafter), and n-
The peak is _C12 to n- _C14 , and the distribution is approximately normal. Note that although there are differences depending on the oil type, this carbon number distribution remains approximately a normal distribution. In other words, n-
Among the paraffin groups, n- with the smallest and largest number of carbon atoms
n-paraffin with a carbon number approximately in the middle of paraffin (for example, if the smallest carbon number is _C10 and the largest carbon number is _C22 , _C16 is in the middle, and n-paraffin with a carbon number in the middle) Paraffin has the highest content (peak content) of _C14 to n- _C18 ,
A state of distribution of carbon numbers in which the content gradually decreases as the number of carbons becomes smaller or larger is called a normal distribution state. In addition, the total amount of n-paraffin and the content by carbon number are based on UOP Method No. 411-75 “Normal
Paraffins by Substractive Gas
Chromatography" method. Incidentally, A heavy oil and B heavy oil are used as diesel engine fuel for small ships and land-based power generation, but this carbon number distribution also has a carbon number distribution of n-C ₁₂ to n- C _25. Problems to be Solved by the Invention The inventors of the present invention aimed to improve the ignitability of various light oil fractions, which are unsuitable as diesel fuel due to their low cetane numbers as described above, by increasing their cetane numbers. As a result of the study, it was found that the addition of kyumene hydroperoxide is effective in improving the cetane number, and that prior to the addition of kyumene hydroperoxide, n - Obtaining the knowledge that the effect of the addition can be synergistically improved by selectively increasing the content of at least one component of the paraffin component group and readjusting the normal distribution state of the n-paraffin. That is, an object of the present invention is to provide a fuel composition for a diesel engine, which has poor ignitability due to its low cetane number, and has improved ignitability. The present invention will be described in detail below.Structure of the Invention The present invention is characterized by adding at least one type of normal paraffin selected from the group consisting of normal paraffins having 10 to 20 carbon atoms to light oil. The present invention provides a diesel fuel composition in which kyumene hydroperoxide is added to a selectively increased content of at least one normal paraffin component present in a normal distribution state.The diesel fuel according to the present invention The light oil used in the composition has an initial distillation property of approximately 200°C to 250°C,
Any material with an end point of 300°C to 400°C may be used. For example, petroleum-based DS-GO is basically used, and as an auxiliary oil, a light oil fraction (hereinafter abbreviated as LCO) produced by the catalytic cracking of heavy oil is used. , hydrocracked gas oil (hereinafter abbreviated as HCGO), which is a by-product during the hydrorefining of heavy oil, GO fraction produced by coal liquefaction (hereinafter referred to as Coal
(abbreviated as GO), tar oil (naphtha decomposition tar) produced by naphtha decomposition, methanol, etc., mixed appropriately can be used. Incidentally, the above-mentioned petroleum-based DS-GO is obtained by atmospheric distillation of paraffinic or mixed base crude oil, separation of the GO fraction, hydrorefining, and then desulfurization and denitrification treatment. If n- in the DS-GO
Paraffin is approximately 15 to 25wt depending on the type of crude oil.
% and typically have a cetane number of about 46-60. On the other hand, the above LCO has a cetane number of 20 or less and almost no n-paraffin is present. The yumene hydroperoxide used in the present invention has the following formula (), is liquid at room temperature, has good solubility in fuel, is stable during long-term storage, and is easy to handle. The amount of kyumene hydroperoxide added to the above light oil should be controlled depending on the cetane number required as a fuel for diesel engines, but it is usually advisable to add it so that it is present in the light oil in an amount of about 0.03 to about 2.0% by weight. . It is preferable that the compound (2) is dissolved in advance at a high concentration in one or more oils of n-paraffin having 10 to 25 carbon atoms to form a concentrate, and then added. In order to further enhance the effect of addition of kyumene hydroperoxide used in the present invention, it is preferable to use light oil in which the carbon distribution state of n-paraffin in the light oil is adjusted according to the following procedure. DS, which is the base stock of light oil used in the present invention
-GO, mixture of DS-GO and LCO, DS-GO and
As mentioned above, the carbon distribution of n-paraffin present in mixtures of HCGO and methanol mixtures is such that the content of n-paraffin with a specific number of carbon atoms is at its peak (i.e., the maximum content). There is a normal distribution in which the content of n-paraffins with larger and smaller carbon numbers gradually decreases. In the present invention, the carbon distribution of n-paraffin, which is in a state of normal distribution, is
It is prepared by adding at least one type of n-paraffin selected from the group consisting of 20 n-paraffins. This adjustment of the carbon distribution of n-paraffin substantially reduces the content of at least one of the n-paraffin components present in a normally distributed state, as shown in Figures 1 and 2 attached hereto. Do this so that you can improve your skills. FIGS. 1 and 2 illustrate an embodiment of adjusting the carbon distribution of n-paraffin present in a normal distribution state in light oil according to the present invention,
Figure 1 shows that the content of n-paraffin, which has 14 carbon atoms, is at its peak with a normal distribution of n-C ₉ to n-C ₂₂ .
- Adding n-paraffin with 12 carbon atoms (n-C ₁₂ paraffin), n-paraffin with 16 carbon atoms (n-C ₁₆ paraffin), or both n-paraffins to light oil containing paraffin components. hand,
In _addition , _FIG . A mixture of n-paraffins with 15 carbon atoms to n-paraffins with 17 carbon atoms (n-C ₁₅ to n-C ₁₇ paraffins) is added to light oil containing paraffin to produce n-paraffins with these carbon numbers. These results indicate that the content of each compound can be selectively increased. n− that exists in the above normal distribution state
When adjusting the carbon distribution of paraffin, the number of carbon atoms in n-paraffin whose content is at the peak in the normal distribution (14 carbons in Figures 1 and 2)
2 to 5 more or less carbon atoms than n
- It is effective to add at least one type of paraffin to light oil to increase the content of the n-paraffin which is in a normal distribution state, and in which the number of carbon atoms is 2 to 5.
It is preferable to increase the content by adding a large amount of n-paraffin. However, increasing the content by adding n-paraffin having too high a carbon number is not preferable because it increases the pour point of the resulting gas oil. As mentioned above, the n-paraffin added to the gas oil may be one type or a mixture of two or more types, and the appropriate amount of n-paraffin added is 3 to 15% by weight, preferably 5 to 15% by weight. If the amount added is too small, the synergistic effect with the addition of kyumene hydroperoxide, which will be described later, will not be sufficiently exhibited. In addition, the n-paraffin to be added is extracted from oil obtained by separating each fraction of kerosene, light oil, or heavy oil using a zeolite molecular sieve or urea adduct method, or is dewaxed during the production of light lubricant base oil. Slack wax and the like produced in the process can be effectively used. Next, in the present invention, kyumene hydroperoxide is added as a cetane number improver to the carbon distribution of the n-paraffin component, which is present in the gas oil in a normal distribution state, which has been adjusted as described above. As mentioned above, the light oil obtained by adding kyumene hydroperoxide to the carbon distribution of the n-paraffin component, which exists in a normal distribution state in light oil, has good ignitability and is suitable for diesel engines. Since it can be operated without knocking, it can be advantageously applied as a diesel engine fuel. Furthermore, according to the present invention, LCO, HCGO, COalGO fractions, methanol, etc., which have conventionally not been used as fuel for diesel engines due to their low cetane numbers, can be mixed with DS-GO etc. and used as the above fuel. Therefore, there is an advantage that the supply source of fuel for diesel engines can be expanded. EXAMPLES AND EFFECTS The present invention will be described in more detail with reference to Examples below. Examples 1 to 9 70:30 ratio of DS-GO (cetane number 51.5) and LCO (cetane number 20 or less) produced by fluid catalytic cracking
(v/v%) of light oil (properties are shown in Table 1), n-paraffins with different carbon numbers were added and mixed, and Qyumene hydroperoxide (manufactured by NOF) A light oil composition was prepared by adding a small amount of . The cetane numbers of the various gas oil compositions obtained were measured using a CFR cetane number measurement engine manufactured by Waukesha, based on the method specified in ASTM-D 613. The results are shown in Table 2. As a comparative example, Table 2 also shows the results of measuring the cetane number of light oil to which only one of the above-mentioned n-paraffin and kyumene hydroperoxide was added. In addition, a sample in which both of the above were not added was shown as a control.

【table】

【table】

[Table] Note) The degree of improvement in cetane number is shown by the difference from the cetane number of the control.
As shown in Table 2, by adding only either n-paraffin or cumene hydroperoxide to light oil, the cetane number can be increased.
Can be improved from 4.2 to 7.0. Furthermore, it can be seen that the cetane number is further synergistically improved when the peroxide is added to a product containing n-paraffin having 10 to 20 carbon atoms.

[Brief explanation of the drawing]

Figure 1 shows the carbon number distribution of n-paraffin present in normal light oil and the state in which n-paraffin with 12 carbon atoms and/or 16 carbon atoms is added. This figure shows a state in which a mixture of 15 to 17 n-paraffins is added.

Claims (1)

[Claims] 1. By adding at least one type of normal paraffin selected from the group consisting of normal paraffins having 10 to 20 carbon atoms to light oil, normal paraffins present in a normal distribution state in the light oil can be reduced. 1. A diesel fuel composition comprising a selectively increased content of at least one paraffin component and addition of kyumene hydroperoxide. 2. The diesel fuel composition according to claim 1, which contains 0.03 to 2% by weight of kyumene hydroperoxide. 3. Among the normal paraffin components present in a normal distribution state in light oil, one or several types of normal paraffin having a carbon number 2 to 5 more than that of the normal paraffin present at the maximum concentration is added to light oil. The diesel fuel composition according to claim 1 or 2, wherein the content of at least one normal paraffin is selectively increased to 5 to 15% by weight.