JP2006233224A - Vegetable oil-containing diesel fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diesel fuel having a 10% actual carbon ratio within a standard value, and significantly reducing the generation of particulate in the whole range of engine load without reducing engine output and without decreasing the 90% distillation temperature to <310°C so as to enable use of a normal light oil. <P>SOLUTION: The diesel fuel comprises 100 pts.vol. mineral oil base which is a light oil having 220-260°C 50% distillation temperature, and 30-100 pts.vol. esterified vegetable oil, and contains 500-1,500 ppm cetane number-improving agent besides them. The diesel fuel is a light oil having 2.0-5.0 (mm<SP>2</SP>/s, 30°C) dynamic viscosity and 51-57 cetane number. As a result, the 10% actual carbon ratio is within the standard value. The amounts of the particulate, hydrocarbon and carbon monoxide in a waste gas in the whole load range of the engine are significantly reduced, and white smoke is hardly generated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel oil for a diesel engine, and more particularly to a diesel fuel containing vegetable oil that can prevent the generation of particulates in a wide engine output range and is easy to manufacture.

  In diesel engines, light oil, heavy oil A and the like are generally used as fuel. These fuels preferably have excellent ignitability and generate less air pollutants (particularly nitrogen oxides (NOx) and particulates (including particulate matter; including black smoke)) contained in the exhaust gas. However, in general mineral oil-based fuels, generation of particulates may be observed due to engine load or the like.

  In order to suppress the generation of particulates, a method of increasing the combustion temperature is effective. However, when the combustion temperature is increased, the generation of nitrogen oxide (NOx) becomes significant. For this reason, an attempt has been made to add both an oxygen-containing compound that can improve the combustibility of light oil and is effective in preventing the generation of NOx, and to prevent both the generation of particulates and the generation of NOx.

  For example, as a fuel capable of suppressing carbon deposits considered to be related to the generation of particulates, JP-A-61-57686 discloses at least one selected from vegetable oil esters, light oil, kerosene, heavy oil, vegetable oil and alcohol. A vegetable oil blend fuel comprising is disclosed. Japanese Patent Application Laid-Open No. 61-57686 discloses a fuel for diesel engines consisting of vegetable oil and / or animal oil, aliphatic alcohol having 1 to 5 carbon atoms and gasoline, and has a low risk of environmental pollution. It can be used. Furthermore, in this specification, there are descriptions concerning British and German patents to which vegetable oil is added. Among these, fuels in which an alkyl fatty acid ester of vegetable oil and an ignition accelerator (cetane number improver) are mixed with mineral oil are also included. Says. Japanese Patent Application Laid-Open No. 7-82576 discloses a low-sulfur diesel fuel in which glycerol ether and methyl ester of vegetable oil are added to mineral oil fuel in order to suppress the generation of particulate matter. JP-A-8-41468 discloses a diesel fuel in which animal and vegetable oils are added to mineral oil to prevent the generation of NOx and black smoke.

  In addition, as an example of diesel fuel in which vegetable oil or alcohol is added to mineral oil, Japanese Patent Publication No. 60-32684 discloses a diesel engine fuel comprising alcohol having 1 to 3 carbon atoms, light oil and castor oil. is there. Japanese Patent Application Laid-Open No. 58-222189 discloses a liquid fuel for power in place of light oil composed of vegetable oil, ethanol, ether and turpentine oil extracted from sunflower seeds. These inventions are mainly aimed at countermeasures against the depletion of petroleum resources, and there is no description about the generation of particulates or NOx, but it is considered as a fuel that can achieve both prevention of particulate generation and prevention of NOx. Further, European Patent No. 665873 discloses a vegetable oil (vegetable oil or esterified vegetable oil) and a mineral oil, and an ethylene copolymer, a linear organic substance having 10 to 30 carbon atoms and oxygen, a polar nitrogen-containing compound (cetane number). A diesel fuel oil to which an improver or the like is added is disclosed.

As described above, the addition of oxygen-containing compounds such as vegetable oil and alcohol is effective in preventing particulate generation and reducing NOx. As means for preventing the generation of particulates, there are known other methods such as lightening the fuel and reducing the aromatic component content. For example, R.A. A. Bouffrd et al. Report that the total particulate concentration increases as the 90% distillation temperature increases, and particularly when the temperature exceeds 600 ° F. (about 316 ° C.), the total particulate concentration rapidly increases (Spec). Publ.Soc.Automot.Eng., SP-502, 1 (1981).). At the same time, it has also been clarified that there is a good correlation between the concentration of aromatic components contained in fractions having a distillation temperature of 640 ° (about 338 ° C.) or higher and the total particulate concentration. Furthermore, JP-A-7-33261 discloses that the generation of particulates can be reduced by setting the end point temperature to 340 ° C. or lower.
JP-A-61-57686 JP 7-82576 A JP-A-8-41468 Japanese Patent Publication No. 60-32684 JP 58-222189 A European Patent No. 665873 Spec. Publ. Soc. Automot. Eng. , SP-502, 1 (1981)

  However, when a large amount of vegetable oil or esterified vegetable oil is used among the aforementioned diesel fuels, the cetane number decreases. When the cetane number falls below 51, white smoke is prominent, so a large amount of cetane number improver is added. However, when a large amount of cetane number improver is added, the 10% residual carbon value of light oil fuel There is a problem that is out of the standard value.

In addition, as a result of investigating the engine load and air pollutants in the exhaust gas, the inventors have changed the light oil properties derived from mineral oil alone or added esterified vegetable oil to it. It has been found that the addition of esterified vegetable oil alone cannot prevent the generation of particulates particularly at low loads. Mineral oil fuel lightening (90% lower distillation temperature) is also effective in preventing particulate generation. However, the effect is weak unless it is significantly lightened. In addition, if the fuel is significantly lightened, the concentration of hydrocarbons and carbon monoxide in the exhaust gas greatly increases, especially at low loads, in either mineral oil fuel or esterified vegetable oil-added fuel. Furthermore, when the mineral oil fuel is lightened (the 90% distillation temperature is lowered to 300 ° C. or lower), the problem of processing heavy components becomes apparent. Another problem with lightening is that when the kinematic viscosity drops below 2.0 mm ² / s (at 30 ° C.), engine output decreases and idling becomes unstable. It is done.

  The present invention has been made to solve the above-described problems. The 10% residual coal value of diesel fuel is within the standard value, the engine output is not reduced, and the 90% distillation temperature is made less than 310 ° C. It is an object of the present invention to provide a mixed fuel of light oil and vegetable oil that can significantly reduce the generation of particulates over the entire engine load range without lowering.

  As a result of intensive studies by the present inventors, a fuel obtained by blending 10 to 100 parts by volume of esterified vegetable oil with 100 parts by volume of a mineral oil base material having a 50% distillation temperature of 200 to 260 ° C is a particulate in the entire load range. It has been found that not only the generation of carbon dioxide can be greatly reduced, but also the concentration of hydrocarbons and carbon monoxide contained in the exhaust gas can be reduced. As a result of further investigation, the addition of 500 to 1000 ppm of a cetane number improver can prevent the generation of white smoke, and even if the 90% distillation temperature of the mineral oil base is 310 to 360 ° C. The inventors have found that it is possible to greatly reduce the occurrence and completed the present invention.

That is, the present invention
(1) 50% distillation temperature is 200 to 260 ° C., and consists of 100 parts by volume of a mineral oil base material and 10 to 100 parts by volume of esterified vegetable oil, and has a kinematic viscosity of 2.0 to 5.0 (mm ² / s, 30 ° C), diesel fuel having a cetane number of 51 to 57,
(2) The vegetable oil-containing diesel fuel according to (1), wherein a 90% distillation temperature of the mineral oil base is 310 to 360 ° C,
(3) The vegetable oil-containing diesel fuel according to any one of (1) to (2), which contains 500 to 1500 ppm of a cetane number improver,
About.

  As described above, the vegetable oil-containing diesel fuel of the present invention can be greatly reduced in the generation of particulates, which is particularly problematic for diesel engines for environmental measures, and is manufactured without using a special mineral oil base material. It is possible and has special effects such as excellent practicality.

  The fuel of the present invention is capable of greatly reducing particulates, hydrocarbons, and carbon monoxide in exhaust gas over the full load range of the engine without causing the 10% residual carbon value of light oil fuel to deviate from the standard value. Occurrence of this is small. In addition, the diesel fuel of the present invention can use light oil and kerosene, which are generally commercially available as the mineral oil base, and can be easily manufactured by blending with esterified vegetable oil. It is a highly practical fuel that is not required.

  The mineral oil base material of the diesel fuel oil of the present invention uses light oil alone or a mixture of light oil and kerosene. Light oil is preferably deep desulfurized gas oil with a sulfur content of 0.05% by mass or less, but since it is mixed with esterified vegetable oil or a mixture of kerosene and esterified vegetable oil, the final sulfur content is 0.05% by mass or less. It should just become.

  When using light oil as a mineral oil base material, a 50% distillation temperature is 200-260 degreeC. However, in order to obtain light oil having such properties by a normal refining process, not only the process becomes complicated, but also the problem of processing heavy components arises. However, the fuel of the present invention can be used without any problem even if the mineral oil base has a 90% distillation temperature of 310 to 360 ° C. Therefore, a method of mixing light oil and kerosene produced from a normal refining process can be employed. When light oil and kerosene are mixed, kerosene is mixed in the range of 30 to 80%, preferably 40 to 70% with respect to the total amount of the mineral base material. If it is less than 30% or more than 80%, the above properties, particularly kinematic viscosity or cetane number may not be satisfied.

  Deep desulfurized gas oil base materials are those obtained by deep desulfurization of straight-run gas oil obtained from crude oil atmospheric distillation equipment, straight-run gas oil, straight-run kerosene obtained from crude oil atmospheric distillation equipment, and secondary cracker from catalytic cracking equipment. It is possible to use a catalytically cracked light oil (LCO) produced, a directly delighted light gas oil produced as a by-product from a heavy oil direct desulfurization apparatus and then deep desulfurized, a hydrocracked oil blended with these, and the like. The apparatus, process and operating conditions for deep desulfurization are not particularly limited, and any known depth desulfurization apparatus, process, etc. can be used in appropriate combination.

  As kerosene, those having a sulfur content of 0.015% by mass or less and a distillation property of 140 to 310 ° C. obtained by hydrodesulfurizing straight-run kerosene obtained from an atmospheric distillation apparatus of crude oil can be used.

  The vegetable oil base of the present invention uses esterified vegetable oil. As a method for producing an esterified vegetable oil, a conventionally known method can be used. For example, a method of reacting a vegetable oil with an alcohol such as methanol or ethanol in the presence of an acid or an alkali and purifying the product by washing with water, etc. be able to. Further, a method improved from the conventional method such as a method described in JP-A-7-31090 and the like may be used.

  The compounding quantity of esterified vegetable oil is 10-100 volume parts with respect to 100 volume parts of mineral oil base materials. When less than 10 parts by volume, the hydrocarbon concentration and carbon monoxide concentration in the exhaust gas tend to increase, which is not desirable. Moreover, although it is a case where it exceeds 100 volume parts, although the density | concentration of a particulate becomes substantially constant, there exists a tendency for NOx to increase, and addition beyond 100 volume parts is still undesirable.

  Examples of the vegetable oil raw material include corn oil, soybean oil, olive oil, rapeseed oil, sesame oil, peanut oil, and palm oil, but there is no need to stick to a specific raw material. Moreover, it is not necessary to be a clarified oil, for example, the waste oil discharged | emitted from the foodstuff processor etc. can be used. Considering environmental problems, it is desirable to use such waste oil.

The kinematic viscosity (30 ° C.) of the fuel of the present invention needs to be 2.0 mm ² / s or more, preferably 2.2 mm ² / s or more. If it is less than 2.0 mm ² / s, not only the engine output decreases, but idling may become unstable. The kinematic viscosity is preferably 5.0 mm ² / s or less. On the other hand, the cetane number is 51 or more, preferably 55 or more in order to prevent the generation of white smoke. However, since the fuel of the present invention contains esterified vegetable oil or kerosene having a low cetane number, it is preferable to add a cetane number improver. When the concentration of the cetane improver exceeds 1500 ppm, the 10% residual coal value of the light oil fuel may deviate from the standard value. For this reason, a cetane number becomes the range of 51-55 substantially. A well-known cetane number improver can be used, for example, nitrate ester, organic peroxide, etc. can be used. The addition amount of the cetane number improver is 200 to 1500 ppm, preferably 500 to 1000 ppm in order to make the cetane number 51 or more.

  Furthermore, the fuel of this invention can use a well-known fuel oil additive individually or in combination. Examples of these additives include low-temperature fluidity improvers such as ethylene vinyl acetate copolymers and alkenyl succinic acid amides, detergent dispersants such as alkenyl succinic acid amides and polyalkylamines, and antioxidants such as phenols and amines. Agents, metal deactivators such as salicylidene derivatives, and colorants such as azo dyes. In addition, friction modifiers such as fatty acids, esters, and alcohols, and anti-wear agents such as organic sulfur compounds and organic phosphorus compounds may be added, but this is not particularly necessary. The compounding amount of these additives is arbitrary, but the compounding amount of each additive is 0.5% by mass or less, preferably 0.2% by mass or less based on the total amount of the composition.

The light oil according to the present invention is not particularly specified for properties other than those described above, but as a fuel for an internal combustion engine, the density (15 ° C.) is preferably 0.82 g / cm ³ or more, and the distillation temperature range in distillation is from 140 to It is 380 degreeC, Preferably it is 150-360 degreeC.

Engines of commercial vehicles shown in Table 1 were used.

Measuring method of particulates, white smoke and engine output The particulates were collected on a filter using a mini dilution tunnel manufactured by HORIBA, Ltd., and the weight of the particulates was measured. As the white smoke, a white smoke meter with a dilution tunnel manufactured by Farmtec Co., Ltd., which measures light opacity using a tungsten lamp as a light source, was used. This white smoke is hydrocarbon fine particles and the like discharged at low temperature start. In addition, the engine output was measured by connecting the engine to a Meidensha DC dynamometer and reading the torque meter data of the company.

Example 1
50 parts by volume of commercially available diesel oil shown in Table 3, 50 parts by volume of kerosene, 25 parts by volume of methyl esterified soybean oil (AG Environmental Products Inc.) and 1000 ppm of a cetane number improver (HITEC; manufactured by Ethyl Co., Ltd.) One vegetable oil-containing fuel was prepared. The fuel properties are shown in Table 2.

D13 mode test A D13 mode test was conducted using the fuel of Example 1, and the concentrations of hydrocarbon (HC), carbon monoxide (CO), nitrogen oxide (NOx) and particulates (hereinafter abbreviated as PM) in the exhaust gas. Was measured. For comparison, the same test was performed with commercial light oils shown in Table 3. Although the relative value with respect to commercial light oil is shown in Table 4, although HC, CO, and NOx are commercial light oil levels, it turns out that the generation amount of PM is reducing significantly.

Particulate concentration measurement test during constant speed operation Using the fuel of Example 1, the PM concentration at engine speeds 1080 and 2160 rpm was measured. For comparison, the same test was performed with commercial light oils shown in Table 3. Although the relative value with respect to commercial light oil is shown in Table 5, Table 6, it turns out that PM is reducing significantly in the full load range.

(Example 2)
A vegetable oil-containing fuel of Example 2 was prepared by blending 100 parts by volume of lightened diesel oil shown in Table 3, 25 parts by volume of methyl esterified vegetable oil, and 1000 ppm of a cetane number improver (HITEC; manufactured by Ethyl). The fuel properties are shown in Table 2.

D13 mode test A D13 mode test was conducted using the fuel of Example 2, and the concentrations of HC, CO, NOx and PM in the exhaust gas were measured. Although the relative value with respect to commercial light oil is shown in Table 4, although HC and CO density | concentration were increasing a little compared with Example 1, PM decreased.

Particulate concentration measurement test during constant speed operation Using the fuel of Example 2, the PM concentration at engine speeds of 1080 and 2160 rpm was measured. Although the relative value with respect to commercially available light oil is shown in Table 5, Table 6, compared with Example 1, the reduction effect of PM was a little large.

(Comparative Example 1)
100 parts by volume of commercially available light oil shown in Table 3, 25 parts by volume of methyl esterified vegetable oil, and 1000 ppm of a cetane number improver (HITEC; manufactured by Ethyl Co., Ltd.) were blended to prepare a vegetable oil-containing fuel of Comparative Example 1. The fuel properties are shown in Table 2.

D13 mode test A D13 mode test was performed using the fuel of Comparative Example 1, and the concentrations of HC, CO, NOx and PM in the exhaust gas were measured. Although the relative value with respect to commercial light oil is shown in Table 4, although HC, CO, and PM are slightly reduced, NOx is increased, and it can be seen that NOx is increased only by adding esterified vegetable oil. .

Particulate Concentration Measurement Test at Constant Speed Operation Using the fuel of Comparative Example 1, the PM concentration at engine speeds 1080 and 2160 rpm was measured. Although the relative value with respect to commercially available light oil is shown in Table 5, Table 6, although the PM reduction effect at the time of high load is large, it turns out that the PM reduction effect at the time of low load is very weak.

(Comparative Examples 2 and 3)
1000 ppm of a cetane number improver was added to the lightened light oil shown in Table 3 to obtain a fuel of Comparative Example 2. Moreover, what added 1000 ppm of cetane number improvers to the 1: 1 mixture of the commercially available light oil and kerosene shown in Table 3 was made into the fuel of the comparative example 3.

D13 mode test D13 mode test was conducted using the fuels of Comparative Examples 2 and 3, and the concentrations of HC, CO, NOx and PM in the exhaust gas were measured. Although the relative value with respect to commercially available light oil is shown in Table 4, although both have the large reduction effect with respect to NOx and PM, it turns out that HC and CO are increasing significantly.

Particulate concentration measurement test during constant speed operation Using the fuels of Comparative Examples 2 and 3, the PM concentration at engine speeds of 1080 and 2160 rpm was measured. Although the relative value with respect to commercial light oil is shown in Table 5 and Table 6, it turns out that although both the PM reduction effect at the time of low load is large, the PM reduction effect at the time of high load is weak.

(Examples 3 to 5 and Comparative Example 4)
100 parts by volume of a mixture of commercially available light oil and kerosene shown in Table 3 was mixed with methyl esterified vegetable oil at a ratio shown in Table 7, and 1000 ppm of a cetane number improver was added thereto. 5 and Comparative Example 4 were prepared.

D13 mode test D13 mode test was conducted using the fuels of Examples 3 to 5 and Comparative Example 4, and HC, CO, NOx and PM concentrations in the exhaust gas were measured. For reference, the results of Example 1 and Comparative Example 3 were added, and the relative values for commercial light oil are shown in Table 7. It can be seen that the concentration of HC and CO increases without the addition of esterified vegetable oil. Moreover, when esterified vegetable oil is added exceeding 100 volume parts, although PM concentration hardly changes, NOx tends to increase.

(Experimental example 1)
Using the fuel A in Table 9, the fuel B in Table 9, the commercial diesel oil in Comparative Example 2, Example 1 and Table 3, the relationship between the maximum output of the engine, the idle speed and the kinematic viscosity was examined. The results are shown in Table 8, and it can be seen that the kinematic viscosity is required to be 2.0 mm ² / s or more.

(Experimental example 2)
A fuel having the cetane number shown in Table 10 was prepared by adding a cetane number improver to the fuel obtained by removing the cetane number improver from the fuel of Example 1. Using this fuel, the relationship between the cetane number and the generation of white smoke was investigated. As a result, it can be seen that white smoke rapidly increases when the cetane number falls below 51. It can also be seen that if the amount of cetane improver added exceeds 1000 ppm, the 10% residual carbon value will exceed 0.1% by mass.

Claims (3)

The 50% distillation temperature is 200 to 260 ° C., and consists of 100 parts by volume of a mineral oil base material that is light oil and 10 to 100 parts by volume of esterified vegetable oil. The kinematic viscosity is 2.0 to 5.0 (mm ² / s, 30 ° C.), diesel fuel having a cetane number of 51 to 57. The vegetable oil-containing diesel fuel according to claim 1, wherein a 90% distillation temperature of the mineral oil base is 310 to 360 ° C. The vegetable oil containing diesel fuel as described in any one of Claims 1-2 which contains 500-1500 ppm of cetane number improvers.