JP2014169362A - Fuel oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel oil used in an internal combustion engine having a combustion chamber adapted to subject a fuel oil and a gas containing oxygen by 65 vol.% or more to combustion, which is low in an amount of exhaust gases such as NOX and THC.SOLUTION: A fuel oil used in an internal combustion engine having a combustion chamber adapted to subject a fuel oil and a gas containing oxygen by 65 vol.% or more to combustion, is characterized in that: on a basis of the total fuel oil amount it contains hydrocarbon oil by 60 vol.% or more; on a basis of the total hydrocarbon oil amount, the content of saturated hydrocarbon is 15 vol.% or more, the content of olefin hydrocarbon is 35 vol.% or less, and the content of aromatic hydrocarbon is 20 to 70 vol.%; the first drop point of distillation is 24°C or more and 80°C or less; the 10 vol.% distillation temperature is 40°C or more and 90°C or less; the 90 vol.% distillation temperature is 170°C or more and 220°C or less; and the end point is 210°C or more and 280°C or less.

Description

The present invention relates to a fuel oil useful in an internal combustion engine that obtains power by burning fuel oil, an internal combustion engine using the fuel oil, and a pneumatic vehicle equipped with the internal combustion engine using the fuel oil.

In an internal combustion engine that obtains power by burning fuel oil such as gasoline, particularly an automobile engine, the fuel oil is mixed with air and subjected to combustion. Nitrogen molecules present in the air at 78.0% generate nitrogen oxides (NOX) such as 1 nitrogen monoxide, 2 nitrogen oxides and their dimers, 3 nitrogen oxides in the combustion process, which are ignored. There is a problem that it is discharged in an amount that cannot be done. Further, the nitrogen contained in the air acts to suppress the action of combustion by oxygen, so that unburned hydrocarbons remain in the combustion chamber and can be discharged as exhaust gas. In order to reduce the emission amount of NOX and total hydrocarbons (THC), a three-way catalyst and a NOX storage reduction catalyst are used.

However, in order to exert its effect, the three-way catalyst requires strict temperature control as well as the amount of fuel oil and air satisfying the stoichiometric air-fuel ratio (stoichiometry), and expensive such as platinum and rhodium. Need noble metals.

Engines that obtain power by burning hydrogen as fuel are known (for example, Patent Documents 1 and 2). In this engine, hydrogen is subjected to combustion together with oxygen and argon gas as a working gas, has a very high thermal efficiency, and does not use nitrogen, so there is no fear of exhausting NOX. However, since hydrogen is used, there is a high risk of explosion, handling is necessary, and it cannot be used easily.

JP-A-11-93681 JP 2009-68392 A

The present inventors have previously found that in the combustion of fuel oil, the amount of exhaust gas such as NOX and THC is reduced by using a gas containing 65% by volume or more of oxygen instead of conventional air. (Japanese Patent Application No. 2012-286842). An object of the present invention is to provide a fuel oil that is useful in an internal combustion engine that obtains power by such combustion, and that has a small amount of exhaust gas such as NOX and THC.

The present inventors have found that the above object is achieved when a fuel oil having a specific composition and distillation properties is subjected to combustion together with a gas containing 65% by volume or more of oxygen.

That is, the present invention relates to a fuel oil used in an internal combustion engine having a combustion chamber adapted to be combusted with a fuel oil and a gas containing 65% by volume or more of oxygen. The content of hydrocarbon oil is 60% by volume or more based on the standard, the content of saturated hydrocarbons is 15% by volume or more, and the content of olefinic hydrocarbons is 35% by volume or less based on the total amount of hydrocarbon oils. The hydrocarbon content is 20 to 70 vol%, the initial distillation point of distillation is 24 ° C or higher and 80 ° C or lower, the 10 vol% distillation temperature is 40 ° C or higher and 90 ° C or lower, and the 90 vol% distillation temperature. Is from 170 ° C. to 220 ° C., and the end point is from 210 ° C. to 280 ° C.
The present invention also relates to an internal combustion engine having a combustion chamber adapted to be combusted with a fuel oil and a gas containing 65% by volume or more of oxygen, wherein the fuel oil is used as the fuel oil. An internal combustion engine is provided.
The present invention also provides a pneumatic vehicle equipped with an internal combustion engine having a combustion chamber adapted to be combusted with a fuel oil and a gas containing 65% by volume or more of oxygen. A diesel powered vehicle using fuel oil is provided.

The fuel oil of the present invention has a small amount of exhaust gas such as NOX and THC when subjected to combustion with a gas containing 65% by volume or more of oxygen. Therefore, in an internal combustion engine that obtains power by such combustion, There is no need to use a three-way catalyst or NOX storage reduction catalyst. In addition, the internal combustion engine using the fuel oil of the present invention can be suitably used in vehicles such as pneumatic vehicles and automobiles.

It is a schematic diagram which shows the internal combustion engine system used in the Example.

The fuel oil of the present invention is used in an internal combustion engine having a combustion chamber adapted to be combusted with a gas containing 65% by volume or more of oxygen.

FIG. 1 is a diagram showing an example of a system including the internal combustion engine. The internal combustion engine 10 has a combustion chamber. In the combustion chamber, the fuel oil supplied from the fuel tank 1 is subjected to combustion together with the gas supplied via the preserver 5. The gas contains 65% by volume or more of oxygen in steady-state combustion. The gas preferably does not contain nitrogen from the viewpoint of suppressing the production of NOX.

The fuel oil of the present invention used in such an internal combustion engine contains 60% by volume or more of hydrocarbon oil based on the total amount of fuel oil, and the content of saturated hydrocarbon is 15% by volume or more based on the total amount of hydrocarbon oil. The olefinic hydrocarbon content is 35% by volume or less, and the aromatic hydrocarbon content is 20 to 70% by volume.

The saturated hydrocarbon content is 15% by volume or more, preferably 20% by volume or more, and more preferably 25% by volume or more from the viewpoint of ensuring startability of combustion. The upper limit of the saturated hydrocarbon content is not limited, but is preferably 80% by volume, more preferably 75% by volume.

The content of the olefinic hydrocarbon is 35% by volume or less, preferably 30% by volume or less, more preferably 25% by volume or less, from the viewpoint of flame propagation characteristics and oxidation stability. It is volume%.

From the viewpoint of combustion efficiency, the aromatic hydrocarbon content is 20 to 70% by volume, preferably 25 to 70% by volume, more preferably 40 to 70% by volume, and still more preferably 30 to 65% by volume.

The content of C7 aromatic hydrocarbon (C7 aromatic) in the aromatic hydrocarbon is not limited, but is preferably 3% by volume to 50% by volume, and preferably 3% by volume to 35% by volume. Is more preferable, and 5 volume% or more and 30 volume% or less are still more preferable. The content of the aromatic hydrocarbon having 9 carbon atoms (C9 aromatic) in the aromatic hydrocarbon is not limited, but is preferably 3% to 50% by volume, and preferably 3% to 35% by volume. Is more preferable, and 5 volume% or more and 30 volume% or less are still more preferable.

The above saturated hydrocarbon content, olefinic hydrocarbon content and aromatic hydrocarbon content are all values measured by the fluorescent indicator adsorption method of JIS K 2536 “Petroleum products-hydrocarbon type test method”. The contents of C7 aromatic and C9 aromatic are values measured by a gas chromatography method in accordance with JPI-5S-33-90.

The paraffin content in the saturated hydrocarbon is not limited at all, but is preferably 60% by volume or more, more preferably 65% by volume or more, still more preferably 70% by volume or more, and 75% by volume. % Or more, still more preferably 80% by volume or more, still more preferably 85% by volume or more, still more preferably 90% by volume or more, Most preferably, it is 95 volume% or more, and although an upper limit is not limited, it is 100 volume%.

The content of the branched paraffin in the paraffin is not limited at all, but is preferably 30% by volume or more, more preferably 50% by volume or more, and 70% by volume from the viewpoint that the amount of THC in the exhaust gas is small. % Is most preferable, and the upper limit is not limited, but is 100% by volume.

The paraffin content and the branched paraffin content are values determined by the gas chromatography method shown below. That is, a capillary column of methyl silicon is used for the column, helium or nitrogen is used for the carrier gas, a hydrogen ionization detector (FID) is used for the detector, the column length is 25 to 50 m, and the carrier gas flow rate is 0.5 to 1. .5 ml / min, split ratio 1:50 to 1: 250, inlet temperature 150 to 250 ° C., initial column temperature −10 to 10 ° C., final column temperature 150 to 250 ° C., detector temperature 150 to 250 ° C. It is the value measured by.

Further, the fuel oil of the present invention has an initial distillation point (IBP) of distillation of 24 ° C. or higher and 80 ° C. or lower, a 10% by volume distillation temperature (T ₁₀ ) of 40 ° C. or higher and 120 ° C. or lower, and 90% by volume. The distillation temperature (T ₉₀ ) is 170 ° C. or higher and 220 ° C. or lower, and the end point (EP) is 210 ° C. or higher and 280 ° C. or lower.

The initial boiling point (IBP) is 24 ° C. or higher and 80 ° C. or lower, preferably 27 ° C. or higher, and more preferably 30 ° C. or higher. The 10% by volume distillation temperature (T ₁₀ ) is 40 ° C. or higher and 120 ° C. or lower, preferably 45 ° C. or higher, and more preferably 50 ° C. or higher. The 90 volume% distillation temperature (T ₉₀ ) is 170 ° C. or higher and 220 ° C. or lower, and preferably 210 ° C. or lower. The end point (EP) is 210 ° C. or higher and 280 ° C. or lower, and preferably 270 ° C. or lower.

When the initial boiling point (IBP) is low, the flammability becomes high and evaporative gas (THC) is easily generated, which causes a problem in handling. The same applies to the ₁₀ % by volume distillation temperature (T ₁₀ ). If the temperature is lower than the above specified value, the flammability becomes high and evaporative gas (THC) is easily generated, which causes a problem in handling. The upper limit values of the 90 vol% distillation temperature (T ₉₀ ) and the end point (EP) are defined from the point that THC in the exhaust gas is small.

The initial distillation point (IBP), 10% by volume distillation temperature (T ₁₀ ), 90% by volume distillation temperature (T ₉₀ ) and end point (EP) of the distillation are determined according to JIS K 2254 “Petroleum products-distillation test method”. The value to be measured. The same applies to the 30% by volume distillation temperature (T ₃₀ ), 50% by volume distillation temperature (T ₅₀ ), and 70% by volume distillation temperature (T ₇₀ ) described below.

In the present invention, the reed vapor pressure (RVP) of the fuel oil is not limited at all, but it is preferably 10 kP or more and 100 kPa or less, and preferably 20 kPa or more, because the handling property such as the flash point is good and the amount of evaporative gas can be kept low. 90 kPa or less is more preferable, 20 kPa or more and 75 kPa or less is even more preferable, and 20 kPa or more and 60 kPa or less is most preferable. The reed vapor pressure (RVP) is measured according to JISK 2258 “Crude oil and fuel oil vapor pressure test method (reed method)”.

In the present invention, the research octane number (RON) of the fuel oil is not limited at all, but is preferably 89.0 or more, more preferably 96.0 or more, because the fuel efficiency of the vehicle is good and the THC in the exhaust gas is small. . The research octane number (RON) is measured according to JIS K 2280 “Octane number and cetane number test method”.

The sulfur content of the fuel oil of the present invention is not limited at all. This is because the fuel oil of the present invention is used in the above-mentioned specific internal combustion engine, and as described above, the amount of exhaust gas such as NOX and THC is small, and therefore a catalyst such as a three-way catalyst is used. It is not necessary. In a conventional internal combustion engine, a catalyst such as a three-way catalyst is used to reduce the amount of exhaust gas such as NOX and THC. When the sulfur content in the fuel oil is high, the catalyst is deactivated. Oil does not require the use of such a catalyst, and therefore the sulfur content is not limited in any way. Preferably, the deterioration of the system of the internal combustion engine can be reduced, etc., so that the total amount of fuel oil is 100 ppm by mass or less, more preferably 50 ppm by mass or less, and further preferably 30 ppm by mass or less. More preferably, it is more preferably 10 ppm by mass or less, still more preferably 1 ppm by mass or less, most preferably 0.1 ppm by mass or less, and the lower limit is not limited, but 0 mass ppm.

The sulfur content is a value measured according to JIS K 2541 “Crude oil and petroleum products—Sulfur content test method” when the content is 1 mass ppm or more. When the content is less than 1 mass ppm, ASTM D4045-96 “ It is a value measured by “Standard Test Method for Sulfur in Petroleum Products by Hydrogenolysis and Rateometric Colorimetry”.

The method for producing the fuel oil of the present invention is not particularly limited. For example, light naphtha obtained by atmospheric distillation of crude oil, heavy naphtha obtained by atmospheric distillation of crude oil, desulfurized full-range naphtha obtained by desulfurizing naphtha fraction obtained by distillation of crude oil, and light naphtha desulfurized. By adding (alkylating) lower olefins to hydrocarbons such as desulfurized light naphtha, desulfurized heavy naphtha obtained by desulfurizing heavy naphtha, and isomerized gasoline and isobutane obtained by converting light naphtha into isoparaffin using an isomerizer. From the obtained alkylate, desulfurized alkylate obtained by desulfurizing alkylate, desulfurized hydrocarbon such as isobutane and low-sulfur alkylate by desulfurized lower olefin, reformed gasoline obtained by catalytic reforming method, reformed gasoline Raffinate (sulfolan raffinate), the residue of aromatics extracted from aromatics, Mass fraction (light reformed gasoline), medium heavy fraction of reformed gasoline (medium heavy reformed gasoline), heavy fraction of reformed gasoline (heavy reformed gasoline), catalytic cracking and hydrogenation Cracked gasoline obtained by cracking method, light fraction of cracked gasoline (light cracked gasoline), heavy fraction of cracked gasoline (heavy cracked gasoline), desulfurized cracked gasoline obtained by desulfurizing cracked gasoline, light fraction of cracked gasoline GTL (Gas) obtained by Fischer-Tropsch synthesis after desulfurized light-decomposed light cracked gasoline, desulfurized heavy-cracked gasoline desulfurized heavy fraction of cracked gasoline, natural gas etc. into carbon monoxide and hydrogen to Liquids), a light fraction (GTL naphtha), LPG (liquefied petroleum gas), and hydrocarbon oil such as desulfurized LPG obtained by desulfurizing LPG. One of the above hydrocarbon oils or a mixture of two or more of them may be produced by desulfurization by hydrogenation or adsorption. Among these hydrocarbon oils, preferred as the base material of the fuel oil of the present invention are light naphtha, desulfurized full-range naphtha obtained by desulfurizing a naphtha fraction obtained by distillation of crude oil, desulfurized light naphtha, isomerized gasoline. Desulfurized alkylate obtained by desulfurizing alkylate, low sulfur alkylate by desulfurized hydrocarbon such as isobutane and lower olefin, desulfurized light cracked gasoline obtained by desulfurizing light fraction of cracked gasoline, GTL light fraction And desulfurized LPG obtained by desulfurizing LPG.

In the production of the fuel oil of the present invention, an oxygen-containing compound may be further added. Examples of the oxygen-containing compound include ethers such as methyl tertiary butyl ether (MTBE) and ethyl tertiary butyl ether (ETBE), and alcohols such as methanol, ethanol, 1-butanol, 2-butanol and isobutanol. . The amount of the oxygen-containing compound in the fuel oil of the present invention is not limited, but is preferably 40% by volume or less, more preferably 20% by volume or less, further preferably 10% by volume or less, and further preferably 7% by volume. It is as follows.

The fuel oil of the present invention includes a colorant for identification, an antioxidant for improving oxidation stability, a metal deactivator, a corrosion inhibitor for preventing corrosion, and a fuel line for maintaining cleanliness. Additives such as a detergent and a lubricity improver for improving lubricity may be added.

The internal combustion engine in which the fuel oil of the present invention is used, in order to perform its start more stably, at the start (that is, at the start of combustion), nitrogen and an optional noble gas are added together with oxygen. It is preferred that the containing gas is supplied to the combustion chamber. The amount of oxygen is 10-50% by volume of gas, preferably 10-40% by volume, the amount of nitrogen is 50-90% by volume of gas, preferably 60-90% by volume, and the amount of rare gas is It is preferably 0 to 20% by volume, preferably 0 to 15% by volume. The noble gas means a group 18 element in the periodic table of elements, and is typically argon.

After starting the internal combustion engine, the proportion of oxygen in the gas can be increased gradually or stepwise, and when operation reaches a steady state (typically 10-30 seconds after the start) A gas containing 65% by volume or more of oxygen, preferably a gas containing 75-100% by volume of oxygen, more preferably a gas containing 85-100% by volume of oxygen, more preferably a gas containing 90-100% by volume of oxygen. Most preferably, by subjecting a gas consisting only of oxygen to combustion, stable operation can be continued and NOX emission can be suppressed. In conventional internal combustion engines that use air, nitrogen contained in a large amount acts in the action of suppressing the combustion of oxygen, so unburned hydrocarbons remain in the combustion chamber and are discharged as exhaust gas. In the internal combustion engine of the invention, since the gas contains 65% by volume or more of oxygen, the amount of unburned hydrocarbons can be reduced, and therefore, the emission amount of total hydrocarbons (THC) can be suppressed. Moreover, since there is little unburned hydrocarbon amount, combustion efficiency is high.

The gas when the operation reaches a steady state may contain nitrogen and / or a rare gas as long as the effects of the present invention are not impaired. The amount of nitrogen that can be included is 0 to 35% by volume of gas, preferably 0 to 15% by volume, and the amount of rare gas is 0 to 10% by volume, preferably 0 to 5% by volume of gas. Within these ranges, there is an effect of lowering the combustion temperature, and even if the gas contains nitrogen, the amount of NOx emitted is small.

The oxygen, nitrogen, and rare gas are preferably used so that the ratio of gas components at the start and thereafter can be adjusted as appropriate, and the pressure fluctuation can be reduced and gas can be stably supplied to the combustion chamber. As shown in FIG. 1, the gas is supplied from each gas cylinder to the combustion chamber. The supply of nitrogen may be performed using an air cylinder in addition to the nitrogen cylinder, or may be performed by natural suction. In FIG. 1, nitrogen, oxygen, and a rare gas (argon) are supplied from the air cylinder 2, the oxygen cylinder 3, and the argon cylinder 4 to the combustion chamber via the preserver 5.

In the internal combustion engine, since the gas subjected to combustion contains oxygen in an amount of 65% by volume or more, NOx emissions are significantly reduced, and therefore expensive three-way catalysts and nitrogen oxide storage reduction catalysts are used. There is no need. This leads to simplification and cost reduction of the internal combustion engine. However, the internal combustion engine in the present invention is not intended to use no catalyst at all, and uses a small amount of a three-way catalyst or other conventionally used catalyst (for example, an adsorbent) as necessary. May be.

The internal combustion engine in the present invention can include a reformer for reforming the fuel oil as necessary. Thereby, the heavy fuel oil with good combustion efficiency can be supplied to the internal combustion engine. In this case, the reforming of the fuel oil may be performed on the entire fuel oil, but is not necessarily required, and may be performed on only a part thereof.

Furthermore, in order to prevent knocking, the internal combustion engine can reduce the compression ratio to, for example, 8.5 or less and / or reduce the cooling water outlet temperature to, for example, 50 to 80 ° C. as necessary. . In order to prevent oxygen inhalation resistance, it is preferable to install a buffer bag that can expand and contract. In order to prevent backfire, it is preferable to use a low rotation range, not to reduce the suction negative pressure too much (for example, not to make it 400 mmHg or less), and / or adjust the valve clearance.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the following examples. Properties and the like of the hydrocarbon oil used in the examples are shown in Tables 1-2.

Examples 1-7
The fuel oil base materials shown in Tables 1 and 2 below were used in the amounts (volume%) shown in Table 3 to produce fuel oils shown in Table 3. The obtained fuel oil was used in the internal combustion engine system shown in FIG. 1 to measure NOX emissions and THC emissions. The results are shown in Table 3. As the internal combustion engine 10, a 4-cycle 2-cylinder engine having a total displacement of 359 cc was used. The fuel oil was supplied from the fuel tank 1, and the gas was supplied from the air cylinder 2, oxygen cylinder 3, and argon cylinder 4 to the preserver 5, and then supplied to the combustion chamber of the internal combustion engine 10. The exhaust gas was treated with the oxidation catalyst 6 and then exhausted through the cooling pipe 7. The discharged gas was mainly argon gas and carbon dioxide, and water was discharged as a liquid.

The operation of the internal combustion engine was performed as follows. That is, at start-up, a gas containing oxygen, argon and nitrogen in amounts of 20.9 vol%, 0.9 vol% and 78.1 vol%, respectively, was supplied to the combustion chamber. After a lapse of 30 seconds from the start, it was confirmed that a steady state was obtained by visual observation, and the operation was continued for another 30 seconds. Thereafter, the gas composition was adjusted to 89.3 vol% oxygen and 10.7 vol% nitrogen. Continued. As a result, it was operated for 100 hours without any trouble. The rotation speed of the internal combustion engine was 3000 rpm, the compression ratio was 7.6, and the cooling water temperature was 60 ° C.

Measurement of NOx emission amount It was confirmed visually that the combustion was in a steady state and the rotational speed of an oscilloscope, and sampling of exhaust gas with a sampling bag was started after 5 to 10 seconds. After sampling for 10 seconds, the collected exhaust gas was immediately introduced into the NOX detector tube, and the amount of NOX was determined from the color change.

Ensure that the measuring <br/> combustion THC emissions has become a steady state at a rotation number of visual and oscilloscope, began collecting in the exhaust gas at the sampling bag after the 5 to 10 seconds. After sampling for 10 seconds, the collected exhaust gas was immediately introduced into the THC detector tube, and the amount of THC was determined from the color change.

Comparative Example 1
In Example 1, the operation was performed in the same manner as in Example 1 except that the gas supplied to the combustion chamber of the internal combustion engine 10 was only air both at the start and in the steady state. NOX emissions were 350 ppm and THC emissions were 500 ppm.

Comparative Example 2
In Example 1, a gas containing 70 vol% oxygen, 29 vol% nitrogen, and 0.9 vol% argon was used as the gas at the start. Backfire occurred and combustion became unstable, so the operation was stopped.

DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Air cylinder 3 Oxygen cylinder 4 Argon cylinder 5 Preserver 6 Oxidation catalyst 7 Cooling pipe 10 Internal combustion engine

Claims (10)

A fuel oil used in an internal combustion engine having a combustion chamber adapted to be combusted with a fuel oil and a gas containing 65% by volume or more of oxygen, and hydrocarbon oil based on the total amount of fuel oil 60% by volume or more, based on the total amount of hydrocarbon oil, the saturated hydrocarbon content is 15% by volume or more, the olefinic hydrocarbon content is 35% by volume or less, and the aromatic hydrocarbon content is 20%. ˜70% by volume, distillation initial boiling point is 24 ° C. or higher and 80 ° C. or lower, 10% by volume distillation temperature is 40 ° C. or higher and 90 ° C. or lower, and 90% by volume distillation temperature is 170 ° C. or higher and 220 ° C. And the end point is 210 ° C. or higher and 280 ° C. or lower. The fuel oil according to claim 1, wherein the content of the aromatic hydrocarbon having 7 carbon atoms in the aromatic hydrocarbon is 3 to 50% by volume. The fuel oil according to claim 1 or 2, wherein the content of the aromatic hydrocarbon having 9 carbon atoms in the aromatic hydrocarbon is 3 to 50% by volume. The fuel oil according to any one of claims 1 to 3, wherein the research octane number is 89.0 or more. The fuel oil according to any one of claims 1 to 4, wherein the lead vapor pressure is 10 kPa or more and 100 kPa or less. The fuel oil according to any one of claims 1 to 5, wherein the sulfur content is 100 ppm by mass or less. The fuel oil according to any one of claims 1 to 6, wherein the content of the aromatic hydrocarbon is 40 to 70 vol% based on the total amount of the hydrocarbon oil. The fuel oil according to any one of claims 1 to 7, comprising an oxygen-containing compound. 9. An internal combustion engine having a combustion chamber adapted to be combusted with a fuel oil and a gas containing at least 65% by volume of oxygen, wherein the fuel oil is any one of claims 1-8. The internal combustion engine, wherein the fuel oil is used. A pneumatic vehicle equipped with an internal combustion engine having a combustion chamber adapted to be combusted with a fuel oil and a gas containing 65% by volume or more of oxygen, wherein the fuel oil is any one of claims 1-8. The diesel train in which the fuel oil according to claim 1 is used.

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