JP6057508B2 - Light oil fuel composition - Google Patents

Description

  The present invention relates to a light oil fuel composition used for a diesel engine or the like.

  In light oil fuel compositions used for diesel engines and the like, low temperature performance is adjusted by using cloud points, pour points, and the like as an index in consideration of use in cold regions and winter seasons. Many methods for obtaining desired low-temperature performance have been proposed.

  For example, in Japanese Patent Application Laid-Open No. 2008-1111082, the weight ratio of the total content of linear paraffins having 15 to 18 carbon atoms to the total content of linear paraffins having 10 to 14 carbon atoms is 0.5 to 1.5. In addition, the weight ratio of the total content of linear paraffins having 15 to 18 carbon atoms to the total content of linear paraffins having 19 to 25 carbon atoms is set to 0.5 to 1.5. A technique for reducing the amount of chain paraffin and enhancing the effect of additives used for improving low temperature performance is disclosed.

  Japanese Patent Application Laid-Open No. 2005-220330 discloses a linearity obtained by determining the slow cooling cloud point (X) from −30.0 to −15.0 ° C. and the normal paraffin content of 18 to 25 carbon atoms in the light oil composition. Normal paraffin having a slope (Y) of the regression line of 0.18 or less, an index (Z) represented by a predetermined formula having X and Y as variables, 1.5 or more, and a carbon number in the composition of 18 or more By reducing the sulfur content to 3.4 mass% or less, there is a technique that satisfies the practical performance and the exhaust gas purification ability without causing filter clogging at a low temperature while suppressing the sulfur content to 50 mass ppm or less. It is disclosed.

JP 2008-111082 A Japanese Patent Application No. 2005-220330

  In recent years, with changes in the social situation, the characteristics of light oil fuel compositions and the points to be considered in the manufacturing method have also changed. Specifically, the content of sulfur and the increase in the mixing ratio of cracked light oil to the light oil desulfurization equipment accompanying the decrease in demand for heavy oil can be mentioned. And with these environmental changes and changes in the demand structure of fuel oil, there are cases where the conventional technology cannot be used to maintain the low temperature performance of light oil, and a new index is required.

  One of the reasons why the conventional technology cannot be used for maintaining the low temperature performance of light oil is that most of the technology pays attention to the properties and precipitation amount of normal paraffin (wax). On the other hand, in order to improve the low-temperature performance of the light oil fuel composition while sufficiently responding to changes in the social situation, the present inventor has increased the mixing ratio of the cracked light oil with the decrease in the sulfur content. In addition to the properties and amount of precipitation, substances that contribute to the amount of wax precipitated at low temperatures, that is, aromatics that are abundant in cracked gas oil, and the composition of naphthene that is produced by hydrogenating aromatics in a desulfurization unit It was found that it is necessary to pay attention to the content.

  An object of the present invention is to provide a light oil fuel composition having a low-temperature performance sufficient for a vehicle fuel while coping with a decrease in the sulfur content and an increase in the mixing ratio of cracked light oil.

  The light oil fuel composition of the present invention has a normal paraffin content of 19 to 23 carbon atoms of 7.5 mass% or less, cycloparaffins of 35 mass% or less, aromatic content of 18 vol% or more, and sulfur content of 10 massppm or less.

The two ring cycloparaffins is less 12.0Mass%, further, Ru der alkylbenzenes or more 12.0mass%.

  In the present invention, cycloparaffins mean alicyclic hydrocarbons, including monocyclic, bicyclic and tricyclic, and those substituted with an alkyl group. Bicyclic cycloparaffins mean bicyclic alicyclic hydrocarbons, including those substituted with an alkyl group.

  Further, in the present invention, alkylbenzenes are those in which a single ring aromatic is substituted with an alkyl group, and pentamethylbenzene, hexamethylbenzene, 1-ethyl-3-methylbenzene, trimethylbenzene derivatives, 1-ethyl- Examples include, but are not limited to, 3,5-dimethylbenzene, 1-methyl-4-propylbenzene, 2-methyl-1,3-dimethylbenzene.

  ADVANTAGE OF THE INVENTION According to this invention, the light oil fuel composition provided with sufficient low-temperature performance for the fuel of a vehicle can be provided, respond | corresponding to the fall of content of sulfur, and the increase in the mixing ratio of cracked light oil.

  Although it is well known that the normal paraffin content called the wax content greatly affects the low-temperature performance of the light oil fuel composition, the present inventor also supplies fuel to the diesel engine among the normal paraffins. Focusing on the matter that precipitates on the filter installed in the system and causes clogging, the composition was analyzed. The result of the analysis is shown in FIG. In collecting the wax to be analyzed, first, the light oil fuel composition is placed in a thermostatic bath at 25 ° C., and rapidly cooled to a temperature 5.0 ° C. higher than the cloud point measured in advance for the light oil fuel composition. The solution was gradually cooled to -5.0 ° C at 1.0 ° C / h. And the precipitated wax was extract | collected using the suction filtration apparatus. Glass fiber filter paper (GF series: GF / A: 1.6 μm) was used for wax collection. Further, the light oil fuel composition remaining in the collected wax was removed using 2-butanone. The obtained wax content was analyzed by gas chromatography.

  As shown in FIG. 1, normal paraffin in light oil is widely distributed from C9 to C30 and has peaks from C16 to C18. On the other hand, the carbon distribution of the wax that causes clogging mainly occupies 19 to 23, and the present inventor adjusts the normal paraffin content of 19 to 23 carbons based on this analysis result. And found that good low-temperature fluidity can be secured. And when the relationship between the normal paraffin having 19 to 23 carbon atoms and the composition and low-temperature fluidity of the other light oil fuel composition was investigated, not only the normal paraffin having 19 to 23 carbon atoms but also aromatics and alkylbenzenes and It has been found that the composition and ratio of cycloparaffins and bicyclic cycloparaffins also affect low temperature performance. That is, it has been found that aromatics, especially alkylbenzenes, in the gas oil fuel composition are excellent in the dissolving power of the precipitated wax, and cycloparaffins, particularly bicyclic cycloparaffins, are inferior in the dissolving power of the precipitated wax. It was found that proper low-temperature fluidity can be ensured even under conditions that meet social conditions by appropriately controlling the amount of aromatics including alkylbenzenes and cycloparaffins including bicyclic cycloparaffins. The present invention is based on these new findings by the present inventors.

It is a graph which shows carbon number distribution of normal paraffin in wax in comparison with carbon number distribution of normal paraffin in light oil fuel composition.

In the light oil fuel composition of the present invention, one or more light oil base materials are treated with a secondary device such as a desulfurization device so as to have a specific property defined by the light oil fuel composition finally obtained. Regardless of the sulfur content of 10 massppm or less or the sulfur content value, one or two or more light oil base materials can be mixed and prepared.
For example, a kerosene fraction and a light oil fraction obtained by atmospheric distillation of crude oil, and a desulfurized kerosene and a desulfurized gas oil obtained by desulfurizing them can be used. A light oil fuel composition having a sulfur content of 10 mass ppm or less obtained by mixing and desulfurizing a light oil fraction obtained from an atmospheric distillation apparatus and cracked light oil at an appropriate ratio can also be used. Note that cracked diesel oil refers to diesel oil distilled from an upgrade process of heavy oil such as directly-desulfurized diesel oil obtained from direct desulfurization equipment, indirectly-desulfurized diesel oil obtained from indirect desulfurization equipment, or light cycle oil obtained from fluid catalytic cracking equipment. The fraction is a fraction, and it is preferable to make the mixing ratio as high as possible in accordance with recent social demands.
Furthermore, light oils obtained by hydrotreating them for improving the hue can also be used. That is, desulfurizer raw material types and ratios so that normal paraffins, cycloparaffins, aromatics, bicyclic cycloparaffins, and alkylbenzenes having 15 to 23 carbon atoms in desulfurized light oil after the desulfurizer treatment are in an appropriate amount. It is possible to use those obtained by adjusting various desulfurization conditions so that these substances that disappear and are generated by the reaction in the desulfurization apparatus are within an appropriate range in the final product.
In addition, the oil refined secondary equipment regardless of whether or not the gas oil after desulfurization satisfies or does not satisfy the proper amount of normal paraffins, cycloparaffins, aromatics, bicyclic cycloparaffins and alkylbenzenes having 15 to 23 carbon atoms. It is also possible to satisfy the above-mentioned appropriate amount by using, as a base material, a gas oil equivalent oil, hydrocracked gas oil, Fischer-Tropsch synthetic oil, etc. distilled from

  The normal paraffin content having 19 to 23 carbon atoms is 7.5 mass% or less. Above that, it is not preferable because the low-temperature performance is deteriorated such that the filter in the fuel supply path to the diesel engine is likely to be clogged when starting at a low temperature. 7.0 mass% or less is more preferable, and 6.0 mass% or less is still more preferable. However, the normal paraffin content having 19 to 23 carbon atoms is preferably as small as possible from the viewpoint of improving low-temperature performance, but from the viewpoint of the cetane index, 4.0 mass% or more, and preferably 5.0 mass% or more. is there.

  Cycloparaffins are 35 mass% or less. 34 mass% or less is more preferable, and 31 mass% or less is still more preferable. Moreover, bicyclic cycloparaffins are 12.0 mass% or less, 11 mass% or less is preferable, More preferably, it is 10 mass% or less. However, if the amount of cycloparaffins or bicyclic cycloparaffins is too small, the rubber seal material may be contracted to cause problems such as fuel leakage and leakage. Therefore, the content is preferably 10 mass% or more or 3 mass% or more, respectively.

  The aromatic content is 18 vol% or more, preferably 20 vol% or more, and more preferably 23 vol% or more. Moreover, 12.0 mass% or more is preferable and, as for alkylbenzenes, 15 mass% or more is more preferable. However, if the aromatic content is too large, the cetane number decreases, causing problems such as an increase in particulate matter in automobile exhaust gas, so 28 vol% or less is preferable.

  The sulfur content needs to satisfy the JIS K 2204 standard determined in consideration of the influence on the environment, that is, 10 mass ppm or less.

Various additives can be appropriately blended in the light oil fuel composition of the present invention as necessary. Examples of such additives include cetane number improvers, surfactants, rust inhibitors, antifoaming agents, detergents, hue improvers, lubricity improvers, and the like. They can be added in combination.
In the present invention, when a low temperature fluidity improver is added, the low temperature fluidity can be further improved.

The following light oil fuel compositions were prepared and the properties shown in Table 1 were measured.
"Example 1"
Using a commercially available desulfurization catalyst, a liquid space is obtained by mixing 95 vol% of a straight-run gas oil fraction having a boiling range of 181 to 352 ° C and 5 vol% of a light cycle oil having a boiling range of 145 to 374 ° C distilled from a fluid catalytic cracker. A light oil fuel composition obtained by desulfurization treatment at a speed of 1.1, a hydrogen partial pressure of 5 MPa, and a hydrogen oil ratio of 170 NL / L until the sulfur content is 10 massppm or less.
"Example 2"
Using a commercially available desulfurization catalyst, 90% by volume of a straight-run gas oil fraction having a boiling range of 181 to 362 ° C. and 10% by volume of light cycle oil having a boiling range of 145 to 374 ° C. distilled from a fluid catalytic cracking unit is used as a liquid space. A light oil fuel composition obtained by desulfurization treatment at a speed of 1.5, a hydrogen partial pressure of 4 MPa, and a hydrogen oil ratio of 150 NL / L until the sulfur content is 10 massppm or less.
"Comparative Example 1"
Using a commercially available desulfurization catalyst, a liquid space is obtained by mixing 98 vol% of a straight-run gas oil fraction having a boiling range of 181 to 372 ° C and 2 vol% of a light cycle oil having a boiling range of 145 to 374 ° C distilled from a fluid catalytic cracker. A light oil fuel composition obtained by desulfurization treatment at a speed of 1.5, a hydrogen partial pressure of 4 MPa, and a hydrogen oil ratio of 150 NL / L until the sulfur content is 10 massppm or less.
“Comparative Example 2”
A straight-run gas oil fraction having a boiling range of 181 to 371 ° C is 85 vol%, a light cycle oil having a boiling range of 145 to 372 ° C distilled from a fluid catalytic cracker is 10 vol%, and a distillate from an indirect desulfurizer having a boiling range of 170 to 365 ° C. Desulfurization of mixed oil with 5 vol% of degassed oil while being put out using a commercially available desulfurization catalyst until the sulfur content becomes 10 massppm or less under conditions of liquid space velocity 1.0, hydrogen partial pressure 5 MPa, hydrogen oil ratio 150 NL / L A light oil fuel composition obtained by processing.
“Comparative Example 3”
A diesel fuel composition collected from the market.

In addition, each property shown in Table 1 is shown below.
“Density (@ 15 ℃)”
Density at 15 ° C. measured by JIS K 2249 “Crude oil and petroleum products—Density test method and density / mass / volume conversion table”.
"Kinematic viscosity (@ 30 ° C)"
Kinematic viscosity at 30 ° C. measured by JIS K 2283 “Crude oil and petroleum products—Kinematic viscosity test method and viscosity index calculation method”.
"Sulfur"
Sulfur content obtained by JIS K 2541-2 "Crude oil and petroleum products-Sulfur content test method Part 2: Micro coulometric titration method".
"Flash point"
Flash point obtained by JIS K 2265-3 "How to determine flash point-Part 3: Penschramtens sealing method".
“Residual carbon content of 10% residual oil”
Residual carbon content of 10% residual oil obtained by JIS K 2270 “Crude oil and petroleum products—Test method for residual carbon content”.
"Cetane index"
It means a cetane index measured according to JIS K 2280 “Petroleum products—fuel oil—octane number and cetane number test method and cetane index calculation method 8. Method for calculating cetane index using 4-variable equation”.
"Distillation properties"
Distillation properties obtained by JIS K 2254 "Petroleum products-Distillation test method".
"Total saturation"
Paraffin content measured by JPI-5S-49-97 "Petroleum products-Hydrocarbon type test method-High performance liquid chromatograph method".
`` Aromatic content total ''
Sum of 1-ring aromatics, 2-rings aromatics and 3 or more-rings aromatic hydrocarbons measured by JPI-5S-49-97 "Petroleum products-Hydrocarbon type test method-High performance liquid chromatograph method" .
"C19-23 normal paraffin content"
Using a gas chromatographic method in accordance with ASTM D 2887 “Standard Test Method for Boiling Range Distribution of Petroleum Fraction by Gas Chromatography”, the carbon content obtained from each carbon content was obtained from the carbon content obtained by carbon chromatography. That is, the retention time was examined using a mixture of normal paraffins having different carbon numbers as a standard, and the content of normal paraffins was determined from the peak area values of normal paraffins. The sum of the chromatogram area values of the peaks between the normal paraffin peaks was determined as the content of isoparaffin having N carbon atoms. Since the gas chromatography detector is a flame ionization detector (FID), the measurement sensitivity is proportional to the carbon number of paraffin. Therefore, taking this sensitivity into consideration, the content molar ratio was determined from the area value, and finally each mass ratio was determined.
The type of column in the gas chromatographic method is HP5 (length: 30 m, inner diameter: 0.32 mm, liquid layer thickness: 0.25 μm), and each analysis condition is as follows.
Column tank temperature rising condition: 35 ° C. (5 minutes) → 10 ° C./minute (temperature rising) → 320 ° C. (11.5 minutes)
Sample vaporization chamber condition: constant 320 ° C. split ratio 150: 1
Detector section: 320 ° C
"Cycloparaffins, naphthenebenzenes, alkylbenzenes"
For the analysis of cycloparaffins, naphthenebenzenes, and alkylbenzenes, a GC system consisting of a gas chromatography with HP-6890N type FI-MS detector manufactured by Agilent Technology and a JMS-T100GC time-of-flight mass spectrometer manufactured by JEOL is used. Then, a correction graph was prepared with the analytical strength of the normal paraffin standard sample, and the measured data was corrected with the correction graph, and then the respective strength ratios were determined with the overall strength being 100 mass%.
The column type in the gas chromatogram method is DB-5 (length: 30 m, inner diameter: 0.25 mm, liquid layer thickness: 0.25 μm), and each analysis condition is as follows.
Column tank temperature rising condition: 30 ° C. (5 minutes) → 20 ° C./minute (temperature rising) → 300 ° C. (27 minutes)
Sample vaporizing chamber conditions: 300 ° C constant Splitless detector: 250 ° C
Solvent: hexane Solvent waiting time: 3 minutes Collection range: 25.00 m / z to 600.00 m / z
"Pour point"
Pour point obtained by JIS K 2269 “Pour point of crude oil and petroleum products and cloud point test method of petroleum products”.
"Cloud point"
Cloud point obtained by JIS K 2269 “Pour point of crude oil and petroleum products and cloud point test method of petroleum products”.
"Clogging point"
A clogging point obtained by JIS K 2288 "Petroleum products-light oil-clogging point test method".
`` Operating limit temperature ''
The operating limit temperature is based on the `` Diesel vehicle filter blockage test manual for low temperature chassis '' that was examined and presented by the `` Diesel Vehicle Fuel Supply System Investigation Special Committee '' of the Petroleum Institute Products Division Fuel Oil Subcommittee. went. The test vehicle is a vehicle equipped with a new short-term regulated diesel engine, which is rapidly cooled from room temperature to the cloud point of each test fuel + 5.0 ° C, then gradually cooled to the test temperature at 1.0 ° C / h, and tested for 1 hour at the test temperature. After holding, the operating limit temperature was confirmed according to the test procedure. The operating limit temperature is the temperature at which starting and running are possible.

  In Table 1, it was confirmed that Example 1 having a small number of normal paraffins having 19 to 23 carbon atoms was excellent in low-temperature performance. Further, even when the normal paraffin content having 19 to 23 carbon atoms is increased with respect to Example 1, it is 7.5 mass% or less, and the cycloparaffins and the aromatic content are set to a predetermined amount. If prepared, more specifically, it was confirmed that deterioration of low-temperature performance could be suppressed if cycloparaffins were 35 mass% or less and the aromatic content was 18 vol% or more.

Claims (1)

Consisting of one or more light oil bases,
Contains a gas oil base that is hydrodesulfurized by mixing cracked gas oil with straight-run gas oil,
The normal paraffin content having 19 to 23 carbon atoms is 7.5 mass% or less, the cycloparaffins are 35 mass% or less, the bicyclic cycloparaffins are 3 mass% or more and 12.0 mass% or less, the aromatic content is 18 vol% or more, and the alkylbenzenes are A light oil fuel composition characterized by having 12.0 mass% or more and a sulfur content of 10 massppm or less.

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