JP5518460B2 - Light oil composition - Google Patents

Description

  The present invention relates to a light oil composition, and more particularly to a light oil composition that can reduce the emission of particulate matter in exhaust gas and has good fuel efficiency.

  Diesel engine exhaust gas contains particulate matter (hereinafter referred to as PM), and recently, from the viewpoint of environmental problems, etc., diesel particulate filters ( There has been proposed a method of reducing the total number of particles and the weight of particles constituting PM released to the atmosphere by providing a diesel particulate filter (hereinafter referred to as DPF).

  On the other hand, the reduction of PM emissions has been studied from the aspect of fuel, and the total amount of PM contained in the exhaust gas, the total number of particles constituting the PM, and the distribution center of the diameter of the particles are determined. It is possible to suppress the emission of light oil compositions (Patent Document 1) capable of simultaneously and sufficiently reducing the number of particles in the vicinity of 50 nm and the amount of aldehydes, and particles having a particle diameter of 50 nm or less. Fuel oil compositions for diesel engines have been proposed (Patent Documents 2 and 3). In addition, nitrogen oxides, hydrocarbons, carbon monoxide, carbon dioxide, PM, fine particles, particles with a diameter of 100 nm or less, emission of aldehydes discharged from the engine during transient operation, reduction to exhaust gas aftertreatment equipment In addition to reducing load, improving fuel efficiency, improving drivability and acceleration, reducing fuel injection pump driving force, and reducing noise during engine operation, engine startability is excellent, oxidation stability is excellent, Light oil compositions that can reduce the influence have been proposed (Patent Documents 4 to 6).

  PM is mainly composed of carbonaceous solid particles and a soluble organic fraction (hereinafter referred to as SOF) that is soluble in an organic solvent. SOF is a source of high-boiling hydrocarbons derived from fuel and lubricating oil. It is assumed that there is. In addition, fine particles (hereinafter referred to as “nanoparticles”) having a particle size of several nanometers to 20 nm are considered to be generated by condensation of volatilized SOF, and although the amount is small, the number of particles is large and the surface area is large. Considering the influence on system cells, it is considered that a smaller discharge amount of nanoparticles is preferable. Nanoparticle emission is observed particularly during deceleration, which is thought to be caused by the unburned fuel adhering to the cylinder wall surface during fuel cut and vaporizing and condensing in the exhaust pipe.

  Further, as described above, the use of DPF is known as an effective means for reducing PM. However, SOF constituting PM captured by DPF has a high temperature due to an increase in load. There is also a possibility that there is a material that evaporates and re-condenses in the atmosphere to form fine particles (Non-patent Document 1).

JP 2004-2550 A JP 2006-232978 A Japanese Patent Laid-Open No. 2006-232979 JP 2004-67899 A JP 2004-269682 A JP 2004-269683 A

“Measurement of car exhausted nanoparticles and DEP and assessment of biological effects”, NTS, p. 6-7, 2005

  Therefore, it is considered important to reduce the emission amount of PM in automobile exhaust gas and to reduce the emission amount of nanoparticles mainly composed of SOF.

  Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to reduce the weight of the entire PM and the number of nanoparticles in the exhaust gas of a diesel engine, and further, a light oil composition with good fuel efficiency. To provide things.

  The inventors of the present invention have conceived that the above-mentioned problems of the prior art can be solved by optimizing specific components and properties in light oil, and the specific components and properties in light oil and the weight of the entire PM, We have intensively studied the correlation between the number and fuel consumption. As a result, in addition to the total aromatic content and polycyclic aromatic content, four components such as hydrocarbons having a molecular weight of 300 or more, aromatic compounds having 10 or more carbon atoms, naphthenes having 10 or more carbon atoms, and paraffins are contained in the entire PM. It turns out that there is a correlation with the weight, the number of nanoparticles and fuel consumption, and by optimizing the content of these components, the weight of the entire PM and the number of nanoparticles in the diesel engine exhaust gas are simultaneously reduced. The present inventors have found that fuel consumption can be maintained well and have completed the present invention.

That is, the light oil composition of the present invention has a total aromatic content of 5 to 16% by volume, a polycyclic aromatic content of 0.5 to 13% by volume, a 90% distillation temperature of 270 to 330 ° C., and a molecular weight of 300 or more. The hydrocarbon content of 15% by volume or less, the paraffin content is 50% by volume or less, and the following formula:
NPI = 0.037 × A + 0.21 × B + 0.054 × C + 0.097 × D
[In the formula, A is the content (volume%) of hydrocarbons having a molecular weight of 300 or more, B is an aromatic content (volume%) having 10 or more carbon atoms, and C is a naphthene content (volume%) having 10 or more carbon atoms. in, D is Ri paraffins (% by volume) der, a is 11.6 to 12.2, B is from 11.3 to 19.5, C is 25.6 to 33.3, D nanoparticles discharge index calculated by 37.8 to 46.5 der Ru] (NPI) is characterized in that it is a 9.1 to 9.6.

The gas oil composition of the present invention, carbon number 10 or more aromatic content of 20% by volume or less, it is preferable that the number 10 or more naphthene carbon is under 35% by volume or less.

  The light oil composition of the present invention has a 1-ring aromatic content of 2.5 to 15 vol%, a cloud point of -10 ° C or less, a 50% distillation temperature of 180 to 272 ° C, and a true calorific value of 42900 kJ / kg or more. Preferably there is.

  According to the light oil composition of the present invention, the weight of the entire PM and the number of nanoparticles contained in the exhaust gas of the diesel engine can be simultaneously reduced, and the fuel efficiency can be maintained well.

(Aromatic content)
In the light oil composition of the present invention, the total aromatic content needs to be in the range of 5 to 16% by volume. If the total aromatic content is within the above range, the weight of the entire PM can be reduced, and low-temperature flow characteristics and fuel consumption can be maintained. In addition, the total aromatic content of the light oil composition of this invention becomes like this. Preferably it is 6-15 volume%, More preferably, it is 8-15 volume%. Similarly, in order to maintain the low-temperature fluidity and fuel consumption while reducing the weight of the entire PM, the polycyclic aromatic content in the light oil composition of the present invention is in the range of 0.5 to 13% by volume. Is preferably 0.5 to 10% by volume, more preferably 0.5 to 5% by volume. The polycyclic aromatic component means an aromatic component having two or more rings. On the other hand, in the light oil composition of the present invention, the monocyclic aromatic component is preferably in the range of 2.5 to 15% by volume, more preferably in the range of 3 to 10% by volume, and still more preferably in the range of 3 to 7% by volume. . If the 1-ring aromatic content is 2.5% by volume or more, the calorific value can be maintained, and if it is 15% by volume or less, the weight of the entire PM in the exhaust gas of the diesel engine is further reduced. Can do. In addition, these aromatic components are calculated | required by the method prescribed | regulated to JPI-5S-49-97 "Petroleum product-hydrocarbon type test method-high performance liquid chromatograph method".

(Distillation properties)
In the light oil composition of this invention, it is necessary to make 90% distillation temperature into the range of 270-330 degreeC from a viewpoint of maintaining a fuel consumption favorable. The 90% distillation temperature is preferably in the range of 280 to 330 ° C, particularly preferably in the range of 290 to 320 ° C, from the viewpoint of further improving fuel consumption. In the light oil composition of the present invention, the 50% distillation temperature is preferably 180 to 272 ° C, more preferably 215 to 265 ° C, particularly preferably 220, from the viewpoint of maintaining good combustion and exhaust gas properties. The range is ˜260 ° C. These distillation properties are determined by a method defined in JIS K2254 “Distillation test method”.

(Nanoparticle emission index NPI)
As described above, the present inventors tried to optimize the content of four components such as a hydrocarbon having a molecular weight of 300 or more, an aromatic compound having 10 or more carbon atoms, a naphthene having 10 or more carbon atoms, and paraffin. To reduce the number of nanoparticles contained in diesel engine exhaust gas, the following formula:
NPI = 0.037 × A + 0.21 × B + 0.054 × C + 0.097 × D
[In the formula, A is the content (volume%) of hydrocarbons having a molecular weight of 300 or more, B is an aromatic content (volume%) having 10 or more carbon atoms, and C is a naphthene content (volume%) having 10 or more carbon atoms. And D is the paraffin content (volume%)], and found that the nanoparticle emission index (NPI) calculated by 9.1 to 9.6 is required. The nanoparticle emission index (NPI) is preferably 9.5 or less, and more preferably 9.2 or less, from the viewpoint of further reducing the nanoparticle emission. In addition, the content of molecular weight 300 or more hydrocarbon (A), while reducing the nanoparticle emissions, to reduce the weight of the entire PM in diesel engine exhaust gases, be a 1 5% by volume or less Is necessary . From the same viewpoint, the aromatic content (B) having 10 or more carbon atoms is preferably 20% by volume or less, more preferably 18% by volume or less, particularly preferably 15% by volume or less, and the naphthene content having 10 or more carbon atoms. (C) is preferably 35% by volume or less, more preferably 30 volume% or less, 28% by volume or less is not particularly preferred. The paraffin content (D) needs to be 50% by volume or less in order to reduce the weight of the entire PM in the diesel engine exhaust gas while reducing the nanoparticle emission amount . The analysis of the component contents (A, B, C, D) consists of an Agilent Technologies HP-6890N type FID detector GC and an JEOL AccuTOF JMS-T100GC time-of-flight mass spectrometer. A GC system was used. Detailed analysis conditions are as follows.

Primary column: Slight polar column (PTE-5 manufactured by Supelco, length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm)
Modulator hollow column: length 2m, inner diameter 0.25mm
Secondary column: High-polarity column (SpelcoWAX10 from Supelco, length 2 m, inner diameter 0.25 mm, film thickness 0.25 μm)
Temperature rising condition: 10 ° C./min (from 50 ° C. (5 min hold) to 280 ° C. (27 min hold))
Inlet temperature: 280 ° C
Injection volume: 1.0 μl
Split ratio: 100: 1
Carrier gas: helium (He), 1.0 ml / min Modulator temperature: The following cold temperature and hot temperature are repeated.
Hot jet gas temperature: The temperature was raised from 150 ° C. (5 minutes hold) to 320 ° C. (33 minutes hold) at 10 ° C./min.
Cold jet gas temperature: about -140 ° C
Modulator frequency: 6 seconds for 0.3 seconds hot temperature, then 5.7 seconds for cold temperature.
Interface hollow column: 0.5m length, 0.25mm inner diameter
FID gas conditions: hydrogen (45 mL / min), air (450 mL / min), make-up helium (25 mL / min)

  Here, the GC system can measure a compound having 7 to 44 carbon atoms, and the compound corresponding to each peak (yamagata) is identified from the elution time and mass spectrum of the measured peak (yamagata). To do. The sum of all identified peaks (yamagata) is defined as the total content (100 peak volume%), and the content of each corresponding compound is calculated as the peak volume% from each peak (yamagata). To do.

(density)
In the light oil composition of the present invention, the density at 15 ° C. is preferably 0.797 to 0.831 g / cm ³ . By setting the density at 15 ° C. within the above range, fuel economy can be maintained satisfactorily. The density at 15 ° C. is more preferably 0.797 to 0.820 g / cm ^{3 and} particularly preferably 0.797 to 0.810 g / cm ³ from the viewpoint of further improving fuel consumption and exhaust gas properties. The density is obtained by a method defined in JIS K2249 “Crude oil and petroleum product density test method”.

(Kinematic viscosity)
In the light oil composition of this invention, it is preferable to make kinematic viscosity in 30 degreeC into the range of 1.8-6.5 mm < ² > / s. By setting the kinematic viscosity at 30 ° C. within the above range, the lubricity of the fuel injection pump can be maintained, and the atomization of the fuel during fuel injection is promoted to improve the exhaust gas properties. Can do. The kinematic viscosity is more preferably in the range of ^{2 to} 6 mm ² / s, particularly preferably in the range of ² to 3.5 mm ² / s, from the viewpoint of further improving the lubricity and exhaust gas properties. Here, the kinematic viscosity at 30 ° C. is determined by a method defined in JIS K2283 “Kinematic Viscosity Test Method”.

(Sulfur content)
In the light oil composition of the present invention, from the viewpoint of reducing sulfur oxides in the exhaust gas, improving the durability of the exhaust gas aftertreatment device, maintaining the lubricity in the fuel injection pump, and maintaining the oxidation stability of the fuel, The sulfur content is preferably in the range of 1 to 7 ppm by mass, more preferably in the range of 1 to 6 ppm by mass, and particularly preferably in the range of 2 to 5 ppm by mass. In addition, a sulfur content is calculated | required by the method prescribed | regulated to JISK2541-6 "Sulfur content test method (ultraviolet fluorescence method)".

(Pour point and cloud point)
In the light oil composition of the present invention, the pour point is preferably set to −10 ° C. or lower, more preferably −15 ° C. or lower, particularly preferably from the viewpoint of maintaining good fuel efficiency while improving drivability at low temperatures. Is −23 ° C. or lower. In addition, although it does not restrict | limit in particular, In the light oil composition of this invention, it is preferable that a pour point is -55 degreeC or more. Similarly, from the viewpoint of maintaining good fuel efficiency while improving drivability at low temperatures, in the light oil composition of the present invention, the cloud point is preferably −10 ° C. or lower, more preferably −12 ° C. Hereinafter, it is particularly preferably −15 ° C. or lower. In addition, although it does not restrict | limit in particular, In the light oil composition of this invention, it is preferable that a cloud point is -25 degreeC or more. Here, the pour point and cloud point are determined by the method specified in JIS K2269 “Pour point of crude oil and petroleum products and cloud point test method of petroleum products”.

(Clogging point)
In the light oil composition of the present invention, the clogging point may be set to −12 ° C. or less from the viewpoints of improving drivability at low temperatures, maintaining good fuel economy, and controlling costs by adding a low-temperature fluidity improver. Preferably, it is −15 ° C. or less, particularly preferably −20 ° C. or less. Moreover, although it does not restrict | limit in particular, In the light oil composition of this invention, it is preferable that a clogging point is -25 degreeC or more. The clogging point is determined by a method defined in JIS K2288 “Petroleum products—light oil—clogging point test method”.

(True calorific value)
In the light oil composition of the present invention, the true calorific value is preferably 42900 kJ / kg or more, more preferably 42950 kJ / kg or more, particularly preferably 43000 kJ / kg or more in order to improve fuel efficiency. Further, although not particularly limited, in the light oil composition of the present invention, the true calorific value is preferably 43400 kJ / kg or less. The true calorific value is obtained by the method defined in JIS K2279 “Crude oil and petroleum products—The calorific value test method and the estimation method by calculation”.

(Preparation of light oil composition)
The gas oil composition of the present invention is used as a raw material oil, for example, various gas oil fractions obtained from an atmospheric distillation apparatus, a catalytic cracking apparatus, a thermal cracking apparatus, etc., that is, a boiling point range from an initial boiling point to an end point (hereinafter referred to as boiling point). Can be obtained by appropriately mixing and hydrodesulfurizing using a distillate distilling in the range of 140 to 400 ° C., or by appropriately mixing after hydrodesulfurization. In order to treat the sulfur content and aromatic content of the product within a predetermined range, it is effective to increase the reaction temperature and the hydrogen partial pressure and to increase the hydrogen / oil ratio. In addition, since the raw material oil containing a lot of aromatics contains a lot of difficult desulfurization components, it is necessary to use a catalyst that selectively removes sulfur in hydrodesulfurization.

Hydrodesulfurization uses a hydrogenation catalyst containing one or more of Co, Mo and Ni, and optionally carrying P, with a reaction temperature of 270 to 380 ° C., preferably 295 to 360 ° C., a reaction pressure of 2.5. To 8.5 MPa, preferably 2.7 to 7.0 MPa, LHSV 0.9 to 6.0 h ⁻¹ , preferably 0.9 to 5.4 h ⁻¹ , and a hydrogen / oil ratio of 130 to 300 Nm ³ / kL. It is good to select suitably from the range so that the above-mentioned light oil composition may be obtained.

  In the present invention, the hydrodesulfurized gas oil fraction is a kerosene fraction, a by-product fraction in producing GTL, BTX, a by-product fraction in producing a lubricating oil, a normal paraffin compound, a normal paraffin series. A light oil composition suitable for the above-mentioned properties and quality is appropriately blended with a solvent, isoparaffin compound, isoparaffin solvent, aromatic compound, aromatic solvent, biomass-derived fuel base material, naphthene compound, naphthenic solvent, etc. Can be prepared.

  In addition, to the light oil composition obtained by the above method, known fuel additions such as a low temperature fluidity improver, an abrasion resistance improver, a cetane number improver, an antioxidant, a metal deactivator, and a corrosion inhibitor are added. An agent may be added. As the low temperature fluidity improver, an ethylene copolymer or the like can be used. In particular, a vinyl ester of a saturated fatty acid such as vinyl acetate, vinyl propionate or vinyl butyrate is preferably used. As the wear resistance improver, for example, a long-chain fatty acid (carbon number 12 to 24) or a fatty acid ester thereof is preferably used, and the wear resistance is sufficient with an addition amount of 10 to 500 ppm by mass, preferably 50 to 100 ppm by mass. Will improve.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

<Preparation of light oil composition>
First, light oil compositions (test light oils 1 to 6) used for the evaluation test were prepared as follows. Analytical values such as the composition of these test diesel oils 1-6 are shown in Tables 1-2. The analysis was performed according to the method described above, but the flash point was measured by the method defined in JIS K2265-3 “How to determine the flash point—Part 3: Penschem Lutens Sealing Method”.

Example 1
Test fuel 1: 30% by volume of commercial No. 1 diesel oil, 40% by volume of Exol D80 (manufactured by TonenGeneral Sekiyu KK), a naphthene / paraffin solvent having a boiling range of 209 to 231 ° C., normal paraffin having 14 to 16 carbon atoms 30% by volume of SHNP (manufactured by Japan Energy Co., Ltd.) was blended and prepared.

( Comparative Example 4 )
Test fuel 2: 10 vol% of commercially available No. 1 diesel oil, 40% by volume of IP solvent 2028 (made by Idemitsu Kosan Co., Ltd.), an isoparaffin solvent having a boiling range of 213 to 262 ° C, and a high boiling point of 290 to 305 ° C Nisseki Hyzol SAS Grade 296 (manufactured by Nippon Petrochemical Co., Ltd.) 11% by volume, GTL gas oil (manufactured by Moss Gas) 37% by volume, and a boiling point range of 350-400 ° C. Nisseki Hyzol SAS Grade LH (manufactured by Nippon Petrochemical Co., Ltd.) 2% by volume was prepared.

(Example 3)
Test fuel 3: Prepared by blending 35% by volume of commercially available No. 1 diesel oil, 53% by volume of commercially available kerosene, and 12% by volume of NA solvent NAS-3 (manufactured by NOF Corporation) having a boiling range of 160 to 195 ° C.

(Comparative Example 1)
Test fuel 4: Commercially available No. 2 diesel oil.

(Comparative Example 2)
Test fuel 5: Commercially available No. 3 diesel oil.

(Comparative Example 3)
Test fuel 6: 40% by volume of GTL gas oil (manufactured by Moss Gas), 30% by volume of IP solvent 2028 (manufactured by Idemitsu Kosan Co., Ltd.), an isoparaffin solvent having a boiling range of 213 to 262 ° C., and a boiling range of 255 to 340 ° C. 30% by volume of NA Solvent NAS-5H (manufactured by NOF Corporation), each of which is an isoparaffinic solvent.

  Next, the test diesel oil was measured for the weight of the entire PM, the number of nanoparticles, and the fuel consumption by the following vehicle using the vehicle shown below. The exhaust gas test was conducted in the 10.15 mode, which is the domestic certification test mode. The results are shown in Table 3.

<Vehicle specifications>
Vehicle name: Toyota Motor Corporation Estima Engine Model: 3C-TE
Total displacement: 2184cc
Compression ratio: 22.6
Maximum output: 69kW / 4000rpm
Maximum torque: 206Nm / 2200rpm
Regulatory compliance: Short-term regulatory compliance (1993-5)

(Measurement of total PM weight)
Measured by the method specified in TRIAS 24-4-1999 “Diesel vehicle 10/15 mode exhaust gas test method”.

(Measurement of the number of nanoparticles)
The exhaust gas from the vehicle was diluted and heated with air using a primary diluter (MD19-2E, manufactured by Matter Engineering) and a secondary diluter (ASET15-1, manufactured by Matter Engineering). The total number of particles of the diluted exhaust gas was measured with a condensation particle counter (made by Condensation Particle Counter, TSI). Furthermore, the nanoparticle discharge | emission amount was calculated | required from the measurement result, and it showed with the relative value on the basis of the comparative example 1. FIG. The dilution conditions are as follows.
Dilution rate: 105 times (primary dilution), 7 times (secondary dilution)
Heating temperature: 80 ° C. (primary dilution), 100 ° C. (secondary dilution)

(Measurement of fuel consumption)
The fuel consumption was measured by the method (carbon balance method) defined in TRIAS 5-4-1999 “Diesel Vehicle 10/15 Mode Fuel Consumption Test Method”.

  From the results shown in Table 3, the sample gas oils of Examples 1 to 3 which are the gas oil composition of the present invention have the same fuel efficiency as that of the sample gas oils of Comparative Examples 1 and 2, but PM It can be seen that the overall weight and the number of nanoparticles can be greatly reduced. The sample gas oil of Comparative Example 3 has a total aromatic content of less than 5% by volume, a polycyclic aromatic content of less than 0.5% by volume, and an NPI of more than 10. Although the weight of PM as a whole is good as compared with the trial light oil, it can be seen that the number of nanoparticles is large and the fuel consumption is also bad. Therefore, the test light oil of Examples 1 to 3 which is the light oil composition of the present invention has a weight and nanoparticles of the total PM contained in the diesel engine exhaust gas as compared with the test light oil of Comparative Examples 1 to 3. It can be seen that both the number of the fuel can be reduced and the fuel efficiency can be maintained well.

  The light oil composition of the present invention can be suitably used as a diesel engine fuel or a mixed base material thereof.

Claims (3)

The total aromatic content is 5 to 16% by volume, the polycyclic aromatic content is 0.5 to 13% by volume, the 90% distillation temperature is 270 to 330 ° C., and the content of hydrocarbons having a molecular weight of 300 or more is 15% by volume. The paraffin content is 50% by volume or less, and the following formula:
NPI = 0.037 × A + 0.21 × B + 0.054 × C + 0.097 × D
[In the formula, A is the content (volume%) of hydrocarbons having a molecular weight of 300 or more, B is an aromatic content (volume%) having 10 or more carbon atoms, and C is a naphthene content (volume%) having 10 or more carbon atoms. in, D is Ri paraffins (% by volume) der, a is 11.6 to 12.2, B is from 11.3 to 19.5, C is 25.6 to 33.3, gas oil composition nanoparticle emission index D is calculated by 37.8 to 46.5 der Ru] (NPI) is characterized in that it is a 9.1 to 9.6.   The gas oil composition according to claim 1, wherein an aromatic content having 10 or more carbon atoms is 20% by volume or less, and a naphthene content having 10 or more carbon atoms is 35% by volume or less.   The single ring aromatic content is 2.5 to 15% by volume, the cloud point is -10 ° C or lower, the 50% distillation temperature is 180 to 272 ° C, and the true heating value is 42900 kJ / kg or higher. The light oil composition according to 1 or 2.