JP2006193683A - Diesel fuel containing fatty acid metal compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diesel fuel capable of keeping the function of a diesel particulate filter (DPF) for a long period by mixing a specific compound to a diesel fuel and provide a diesel fuel additive composed of the compound. <P>SOLUTION: The diesel fuel contains a fatty acid metal compound expressed by formula (1): (CnHmCOO)<SB>l</SB>M (1) (n is an integer of 5-21; m is 2n-1, 2n-3, 2n-5 or 2n-7; l is an integer of 1-4; and M is selected from alkali metals, Li, Na, K, Ag, Mg, Ca, Zn, Cu, Sr, Co, Ni, Sn, Al, Ti and Zr). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a diesel fuel, and more particularly, to a diesel fuel capable of maintaining the function of an apparatus for removing particulate matter (hereinafter sometimes referred to as “PM”) for a long period of time.

  Currently, hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM) are subject to regulations regarding exhaust emissions from diesel engines. With regard to PM, the ordinance for environmental protection (for example, the “Ordinance on Ensuring the Health and Safety of the Citizens” by the Tokyo Metropolitan Government) was enforced in October 2003 in the Kanto area including Tokyo. Vehicles that do not meet the standard values stipulated in the section are equipped with PM removal devices (diesel particulate filters: devices that collect PM contained in exhaust gas from diesel engines with a ceramic filter; hereinafter referred to as “DPF”) Became mandatory. Penalties are to be applied to those who violate the regulations.

  There are two types of DPF. One is a type (collecting type) that adsorbs PM with an adsorbent with a large surface area and performs oxidation treatment such as incineration. The other is an oxidation catalyst that carries an oxidation catalyst on an exhaust gas filter. This is a type in which PM adsorbed by the surrounding adsorbent is oxidized on this oxidation catalyst (oxidation catalyst type).

  Each method has advantages and disadvantages, and the former is economical in that a sulfur concentration of 500 ppm or less can be used as a diesel fuel, but the travel distance until incineration processing is limited depending on the amount of PM generated. (For example, 100 km to 300 km). On the other hand, the latter does not limit the travel distance, but the diesel fuel that can be used is limited to low-sulfur diesel oil with a sulfur concentration of 50 ppm or less, the free accelerator black smoke concentration is 40% or less, or exhausted during one-day travel. In general, various restrictions are imposed such that the ratio of the temperature is 260 ° C. or higher is 5% or more. Therefore, a means for eliminating these disadvantages, maintaining the DPF PM processing function as long as possible, and extending the service life is desired.

  In October 2003, it was obliged to install the DPF mainly in Tokyo, but when actually driving, the filter was clogged or the function was lost due to driving only a few tens of kilometers. The voice is raised. The manufacturer has various restrictions such as designating low-sulfur diesel oil of 50 ppm or less as usable diesel oil in order to extend the service life, but there are problems of supply instability and cost increase. The collection type DPF requires maintenance once a day, and the oxidation catalyst type DPF loses its function at an early stage.

  On the other hand, it is recognized worldwide that the composition of diesel fuel greatly affects the generation of PM in exhaust gas. In particular, the sulfur concentration, aromatic compound concentration, cetane number and the like are listed as the main factors for PM generation. Considering these, low emission type synthetic diesel fuel has been developed in recent years. The feature of this low emission type synthetic diesel fuel is that it contains oxygen due to the chemical structure of the fuel.

  Since the 1990s, biodiesel fuel has attracted attention in consideration of the global warming problem. Biodiesel fuel generally includes rapeseed oil, soybean oil, palm oil, palm kernel oil, sunflower oil, rice oil, sesame oil, corn oil, coconut oil, safflower oil, safflower oil, peanut oil, cottonseed oil, linseed oil, mustard Vegetable oils such as oil are methyl esterified to make diesel engine fuel.

  Biodiesel fuel is an oxygen-containing fuel that contains oxygen in its chemical structure, and since it contains almost no sulfur, it emits less harmful exhaust gases such as black smoke. In addition, because it is plant-derived, carbon dioxide emissions are counted as zero in the provisions of the Kyoto Protocol. For this reason, biodiesel fuel has been attracting attention as a light oil alternative fuel with a low environmental impact, and standards and legal systems have already been established in Europe and the United States, and over 2.5 million tons are produced and used annually from soybeans and rapeseed oil.

  On the other hand, in Japan, about 5000 tons / year of biodiesel fuel is produced from waste cooking oil and used in some local governments. In Japan, standards are not yet established, but in recent years, bioethanol and biodiesel fuels will be standardized.

  It has long been known that fatty acid alkyl esters can be obtained by transesterification of monoglycerides, diglycerides, and triglycerides, which are the main components of fats and oils, with alkyl alcohols (for example, JP-A-2002-167356 (Patent Documents). 1), JP 2002-294277 A (Patent Document 2), JP 2000-44984 A (Patent Document 3)). It is also known that a fatty acid alkyl ester can be obtained by an esterification reaction between a free fatty acid and an alkyl alcohol (for example, “Organic Chemistry Handbook”, Gihodo Publishing, 1988, p1407 to p1409 (Non-patent Document 1)).

  In addition, various techniques for producing biodiesel fuel oils from fats and oils under supercritical alcohol conditions have been studied so far (for example, Japanese Patent Application Laid-Open No. 2002-241786 (Patent Document 4) and Japanese Patent Application Laid-Open No. 2001-302484). (Patent Document 5), JP-A-2000-109883 (Patent Document 6) and the like).

  The biodiesel fuel obtained in this manner has the property that it is less likely to generate PM because it is an oxygen-containing fuel having oxygen in the molecule and hardly contains sulfur. According to the inventors' experiments, it has been found that adding about 20% of biodiesel fuel to conventional gas oil reduces the black smoke concentration by 70%. Furthermore, it has been confirmed that when the vehicle is driven with 100% biodiesel fuel, the black smoke concentration is reduced by 90% or more.

  However, even if biodiesel fuel is used, soluble organic substances (SOF: generally unburned fuel components) in PM are discharged without reduction. Since the total amount of PM is the total amount of black smoke and SOF, it is necessary to use DPF to completely clear the standard value of exhaust gas stipulated in the regulations. Although it is clear that biodiesel fuel is effective in extending the life of DPF compared to general light oil (generally 1.5 to 3 times that of light oil), it is actually used. From the viewpoint of the environment, it is expected that the DPF will last longer.

In order to solve the above problems, it has been proposed to improve the quality of emitted gas due to combustion of diesel fuel. For example, JP 2004-35883 A discloses that the performance of a PM trap used in an exhaust gas system of a diesel engine is improved by adding an iron salt composition to diesel fuel (Patent Document). 7). However, there are still many problems to be solved for extending the life of the DPF, and it is difficult to say that it is sufficient.
JP 2002-167356 A JP 2002-294277 A JP 2000-049484 A Japanese Patent Laid-Open No. 2002-241786 JP 2001-302584 A JP 2000-109883 A JP 2004-35883 A "Organic Chemistry Handbook", Gihodo Publishing, 1988, p1407-p1409

  The present invention has been made paying attention to the above situation, and its purpose is to maintain the function of the PM removal device (DPF) over a long period of time by mixing a specific compound with diesel fuel. Another object of the present invention is to provide a diesel fuel additive and a diesel fuel additive comprising the compound.

In order to solve the above problems, the present invention provides a diesel fuel containing a fatty acid metal compound, wherein the fatty acid metal compound is represented by the following formula (1).
(CnHmCOO) _l M (1)
(Where l is an integer of 1 to 4, n is an integer of 5 to 21, m is 2n-1, 2n-3, 2n-5 or 2n-7, M is an alkali metal, Li, Na, K , Ag, Mg, Ca, Zn, Cu, Sr, Co, Ni, Sn, Al, Ti, Zr.)

  In diesel fuel containing a fatty acid metal compound, PM adsorbed on the DPF is immediately oxidized and decomposed, so that the adsorption surface of the DPF is always kept fresh without PM accumulating. As a result, the function of the DPF can be maintained for a long time.

  Preferred embodiments of the present invention are as follows. The concentration of the fatty acid metal compound is preferably 1 to 50 ppm. Further, the diesel fuel preferably has a sulfur concentration of 50 ppm or less and a cetane number of 50 or more. The diesel fuel preferably includes a biodiesel fuel obtained by methyl esterifying vegetable oil.

Moreover, this invention contains the fatty-acid metal compound shown by following formula (2), and provides the additive for diesel fuels added to a diesel fuel.
(CnHmCOO) _l M (2)
(Where l is an integer of 1 to 4, n is an integer of 5 to 21, m is 2n-1, 2n-3, 2n-5 or 2n-7, M is an alkali metal, Li, Na, K , Ag, Mg, Ca, Zn, Cu, Sr, Co, Ni, Sn, Al, Ti, Zr.)

  With such a configuration, in the diesel fuel to which the fatty acid metal compound is added, the PM adsorbed on the DPF is immediately oxidized and decomposed, and the adsorbed surface of the DPF is always maintained in a fresh state without accumulating PM. As a result, the function of the DPF can be maintained for a long time.

  According to the present invention, the above-described problems can be solved, and the PM regulation measures that are profitable for the side using the DPF can be performed, and the PM regulations that are highly feasible for the government side can be performed. . Further, as a secondary effect of the present invention, if biodiesel fuel is used as the diesel fuel, carbon dioxide emissions can be reduced, and thus global warming prevention measures can be taken.

  Next, the embodiment of the diesel fuel according to the present invention will be described in more detail. The diesel fuel according to the embodiment of the present invention includes a fatty acid metal compound. That is, the fatty acid metal compound is mixed with the diesel fuel within the fuel standard value (less than 5 mg / kg).

  FIG. 1 is a diagram showing a series of steps until PM generated from diesel fuel according to the present embodiment is processed by a collection-type DPF. In FIG. 1, the example using the biodiesel fuel containing a fatty-acid metal compound is shown as a diesel fuel which concerns on this embodiment.

  The diesel fuel according to this embodiment reduces the emission amount of particulate matter (PM) 1 generated when the diesel fuel burns in a diesel engine (not shown) by the effect of the fatty acid ester compound, and the generated PM1 The particle diameters of the PM1a, 1b, and 1c are reduced.

  When the diesel fuel according to the present embodiment burns, the metal in the fatty acid metal compound is oxidized and the oxide 2 adheres to the surfaces of the miniaturized PMs 1a, 1b, and 1c.

  The PMs 1a, 1b and 1c to which the metal oxide 2 is attached are adsorbed on the collection surface 3 of the PM removal device (DPF). The collection surface 3 is generally made of a ceramic containing a metal oxide such as silicon.

  PM1a, 1b and 1c adsorbed on the collection surface 3 of the PM removal device (DPF) as described above are caused by the combined catalytic action with the metal oxide 2 on the collection surface 3 and the interaction with the exhaust gas temperature. PM1a, 1b and 1c are instantly oxidized and decomposed into carbon dioxide. As a result, the collection surface 3 is always kept fresh. Such an effect is the same also in the oxidation catalyst type DPF.

  The above fatty acid metal compounds can be mixed not only with low-emission diesel oil such as biodiesel fuel, but also with conventional fossil fuel-based diesel oil. be able to.

As the fatty acid metal compound, one represented by the following formula (1) is used.
(CnHmCOO) _l M (1)
(Where l is an integer of 1 to 4, n is an integer of 5 to 21, m is 2n-1, 2n-3, 2n-5 or 2n-7, M is an alkali metal, Li, Na, K , Ag, Mg, Ca, Zn, Cu, Sr, Co, Ni, Sn, Al, Ti, Zr.)

  Examples of the fatty acid metal compound of the above formula (1) include potassium palmitate, sodium palmitate, magnesium palmitate, calcium palmitate, potassium stearate, sodium stearate, magnesium stearate, calcium stearate, potassium oleate, and olein. Examples thereof include sodium acid, magnesium oleate, and calcium oleate. These can be used not only as one kind but also as a mixture of two or more kinds.

  The concentration of the fatty acid metal compound is preferably 1 to 50 ppm, more preferably 10 to 30 ppm in consideration of the specifications of diesel fuel and the upper and lower limits of the effect.

  Moreover, it is preferable that the density | concentration of the sulfur in diesel fuel is 50 ppm or less from a viewpoint of reducing generation | occurrence | production of sulfur oxide as much as possible, and a cetane number is 50 or more from a viewpoint of combustibility as a fuel. In consideration of these, it is preferable to use a low-sulfur gas oil or a biodiesel fuel obtained by methyl esterifying a plant from which sulfur content has been significantly removed during the petroleum refining process. The biodiesel fuel production apparatus and production method are described in detail in Japanese Patent No. 3530884 and Japanese Patent No. 3530885.

The present invention also provides an additive for diesel fuel containing a fatty acid metal compound represented by the following formula (2) and added to diesel fuel.
(CnHmCOO) _l M (2)
(Where l is an integer of 1 to 4, n is an integer of 5 to 21, m is 2n-1, 2n-3, 2n-5 or 2n-7, M is an alkali metal, Li, Na, K , Ag, Mg, Ca, Zn, Cu, Sr, Co, Ni, Sn, Al, Ti, Zr.)

  Examples of the fatty acid metal compound of the above formula (2) include potassium palmitate, sodium palmitate, magnesium palmitate, calcium palmitate, potassium stearate, sodium stearate, magnesium stearate, calcium stearate, potassium oleate, and olein. Examples thereof include sodium acid, magnesium oleate, and calcium oleate. These can be used not only as one kind but also as a mixture of two or more kinds.

  The amount of the additive for diesel fuel is preferably added so that the concentration in the diesel fuel is 1 to 50 ppm, considering the specifications of the diesel fuel and the upper and lower limits of the effect. Is more preferable.

  The form of the additive for diesel fuel is not particularly limited, and can take any form such as powder, granule, tablet, and liquid. The purity of the diesel fuel additive is preferably at least 98% or more.

  First, as a diesel fuel additive (fatty acid metal compound), potassium stearate having a purity of 99% or more is used, and this is a fatty acid methyl esterified fuel (a sulfur concentration of 1.0 ppm, a cetane number of 55) so as to have a concentration of 20 ppm. The desired diesel fuel was prepared by adding to (diesel fuel). This is filled into a 3000 cc, 8 ton truck (1999 regulated vehicle) fuel tank equipped with a collection type DPF [external power regeneration type DPF (trade name: Mocoby ZK, manufactured by Comotec)] I went on the road.

  While traveling, the “warning light” equipped on the DPF was observed, and the distance traveled until the lamp reporting the loss of catalyst function was measured. In addition, the DPF body was visually checked at every filter replacement limit distance when traveling with light oil having a normal sulfur concentration (50 ppm or less) to determine the durability of the PM removal function. The results are shown in Table 1.

  The test was conducted in the same manner as in Example 1 except that a 1: 1 mixture of potassium stearate and potassium oleate was used as an additive for diesel fuel (fatty acid metal compound). The results are shown in Table 1.

  The test was performed in the same manner as in Example 1 except that the fatty acid potassium salt generated in the production process of the fatty acid methyl esterified fuel (biodiesel fuel) was used as an additive for diesel fuel (fatty acid metal compound). The fatty acid composition was palmitic acid: stearic acid: oleic acid: linoleic acid = 1: 1: 7: 1. The results are shown in Table 1.

  The test was conducted in the same manner as in Example 1 except that sodium stearate was used as an additive for diesel fuel (fatty acid metal compound). The results are shown in Table 1.

  The test was conducted in the same manner as in Example 1 except that calcium stearate was used as an additive for diesel fuel (fatty acid metal compound). The results are shown in Table 1.

  The test was performed in the same manner as in Example 1 except that the concentration of calcium stearate used in Example 5 was 40 ppm. The results are shown in Table 1.

  The test was performed in the same manner as in Example 1 except that the concentration of potassium stearate was 10 ppm. The results are shown in Table 1.

  The test was performed in the same manner as in Example 1 except that the concentration of potassium stearate was 40 ppm. The results are shown in Table 1.

  Example 1 except that a fuel obtained by mixing 20% by volume of a fatty acid methyl esterified fuel (biodiesel fuel) containing 20 ppm of potassium stearate having a purity of 99% or more with a light oil (sulfur concentration of 50 ppm or less, JIS No. 2) was used. Were tested in the same manner. The results are shown in Table 1.

Example 1 except that a fuel obtained by mixing 50% of a fatty acid methyl esterified fuel (biodiesel fuel) containing 20 ppm of potassium stearate having a purity of 99% or more with a light oil (sulfur concentration of 50 ppm or less, JIS No. 2) was used. The same test was performed. The results are shown in Table 1.
[Comparative Example 1]

The test was conducted in the same manner as in Example 1 except that a diesel oil containing no fatty acid metal compound (sulfur concentration: 50 ppm or less, JIS No. 2) was used as the diesel fuel. The results are shown in Table 1.
[Comparative Example 2]

  The test was conducted in the same manner as in Example 1 except that only a fatty acid alkyl esterified fuel (biodiesel fuel) containing no fatty acid metal compound was used as the diesel fuel. The results are shown in Table 1.

  First, as a diesel fuel additive (fatty acid metal compound), potassium stearate having a purity of 99% or more is used, and this is a fatty acid methyl esterified fuel (a biodiesel fuel having a sulfur concentration of 1 ppm and a cetane number of 55). ) Was added to prepare the desired diesel fuel. This is filled in a 3000 cc, 8-ton truck (1999 regulated vehicle) fuel tank equipped with an oxidation catalyst type DPF [Johnson Massey CRT method (trade name: CRT-TSS SOW-301B, manufactured by Mitsui & Co., Ltd.)]. And I went on a general road.

  While traveling, the “warning light” equipped on the DPF was observed, and the distance traveled until the lamp reporting the loss of catalyst function was measured. In addition, the DPF body was visually checked at every filter replacement limit distance when traveling with light oil having a normal sulfur concentration (50 ppm or less) to determine the durability of the PM removal function. The results are shown in Table 2.

  The test was performed in the same manner as in Example 11 except that potassium stearate was changed to 10 ppm. The results are shown in Table 2.

  Example 11 except that 20% by volume of fatty acid methyl esterified fuel (biodiesel fuel) containing 20 ppm of potassium stearate having a purity of 99% or more was mixed with light oil (sulfur concentration 50 ppm or less, JIS No. 2). Were tested in the same manner. The results are shown in Table 2.

Example 11 except that a fuel in which 50% by volume of a fatty acid methyl esterified fuel (biodiesel fuel) containing 20 ppm of potassium stearate having a purity of 99% or more was mixed with light oil (sulfur concentration 50 ppm or less, JIS No. 2) was used. Were tested in the same manner. The results are shown in Table 2.
[Comparative Example 3]

The test was conducted in the same manner as in Example 11 except that diesel oil containing no fatty acid metal compound and having a sulfur concentration of 50 ppm or less was used. The results are shown in Table 2.
[Comparative Example 4]

  The test was conducted in the same manner as in Example 11 except that only a fatty acid alkyl esterified fuel (biodiesel fuel) containing no fatty acid metal salt was used as the diesel fuel. The results are shown in Table 2.

It is a figure which shows a series of processes until PM generate | occur | produced from the diesel fuel which concerns on this embodiment is processed by the collection type | mold DPF.

Explanation of symbols

1: PM, 1a, 1b and 1c: Miniaturized PM, 2: Metal oxide, 3: Collection surface

Claims (6)

A diesel fuel containing a fatty acid metal compound, wherein the fatty acid metal compound is represented by the following formula (1).
(CnHmCOO) _l M (1)
(Where l is an integer of 1 to 4, n is an integer of 5 to 21, m is 2n-1, 2n-3, 2n-5 or 2n-7, M is an alkali metal, Li, Na, K , Ag, Mg, Ca, Zn, Cu, Sr, Co, Ni, Sn, Al, Ti, Zr.)   The diesel fuel according to claim 1, wherein the concentration of the fatty acid metal compound is 1 to 50 ppm.   The diesel fuel according to claim 1 or 2, wherein the concentration of sulfur is 50 ppm or less.   The diesel fuel according to any one of claims 1 to 3, wherein the cetane number is 50 or more.   The diesel fuel according to claim 1, wherein the diesel fuel includes biodiesel fuel obtained by methyl esterifying vegetable oil. An additive for diesel fuel, which contains a fatty acid metal compound represented by the following formula (2) and is added to diesel fuel.
(CnHmCOO) _l M (2)
(Where l is an integer of 1 to 4, n is an integer of 5 to 21, m is 2n-1, 2n-3, 2n-5 or 2n-7, M is Li, Na, K, Ag, (Selected from the group consisting of Mg, Ca, Zn, Cu, Sr, Co, Ni, Sn, Al, Ti, Zr.)

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