JP2014169363A - 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 30 vol.% or more, the content of olefin hydrocarbon is 10 vol.% or less, the content of aromatic hydrocarbon is 65 vol.% or less, and the content of naphthenic hydrocarbon is 45 vol.% or less; and the first drop point of distillation is 100°C or more.

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 30% by volume or more, and the content of olefinic hydrocarbons is 10% by volume or less, based on the total amount of hydrocarbon oils. The fuel oil characterized by having a hydrocarbon content of 65% by volume or less, a naphthenic hydrocarbon content of 45% by volume or less, and an initial boiling point of distillation of 100 ° C. or more.
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 is a hydrocarbon oil of 60% by volume or more, preferably 80% by volume or more, more preferably 90% by volume or more, more preferably 93%, based on the total amount of fuel oil. Including 100% by volume, based on the total amount of hydrocarbon oil, the saturated hydrocarbon content is 30% by volume or more, the olefinic hydrocarbon content is 10% by volume or less, and the amount of aromatic hydrocarbons is 65% by volume. %, The naphthenic hydrocarbon content is 45% by volume or less, and the initial boiling point of distillation is 100 ° C. or more.

The saturated hydrocarbon content is 35% by volume or more, preferably 50% by volume or more, more preferably 60% by volume or more, and further preferably 70% by volume or more, from the viewpoint of ensuring startability of combustion. The upper limit is not limited, but is preferably 100% by volume, more preferably 95% by volume, and more preferably 90% by volume.

The olefinic hydrocarbon content is 10% by volume or less from the viewpoint of flame propagation characteristics and oxidation stability, and the lower limit is not limited, but is preferably 0% by volume.

From the viewpoint of combustion efficiency, the aromatic hydrocarbon content is 65 volume% or less, preferably 50 volume% or less, preferably 0 volume% or more, more preferably 30 volume% or more, and more preferably 40 volume% or more. Further preferred.

The naphthenic hydrocarbon content is 45% by volume or less, preferably 40% by volume or less, more preferably 30% by volume or less from the viewpoint of reducing the amount of THC in the exhaust gas, and the lower limit is not limited. Preferably, it is 0% by volume.

The above saturated hydrocarbon content, olefinic hydrocarbon content and aromatic hydrocarbon content are values measured by the HPLC method defined in JPI-5S-49-97. The naphthenic hydrocarbon content is a value measured by ASTM D2425 “Standard Test Method for Hydrocarbon Types in Middle Distillates by Mass Spectrometry”.

The distillation property of the fuel oil of the present invention is not limited except that the initial boiling point (IBP) of distillation is 100 ° C. or higher, but the initial boiling point (IBP) is 100 ° C. or higher and 190 ° C. or lower. It is preferably 130 ° C. or higher and 190 ° C. or lower, and most preferably 145 ° C. or higher and 190 ° C. or lower. If the initial boiling point is low, the flammability becomes high and evaporative gas (THC) is likely to be generated, which causes a problem in handling.

Except for the initial boiling point of distillation, the 10% by volume distillation temperature (T ₁₀ ) is preferably 120 ° C. or higher and 210 ° C. or lower, more preferably 140 ° C. or higher and 230 ° C. or lower, and most preferably 160 ° C. or higher and 230 ° C. or lower. Further, the 30% by volume distillation temperature (T ₃₀ ) is preferably from 160 ° C. to 220 ° C., and the 50% by volume distillation temperature (T ₅₀ ) is preferably from 180 ° C. to 240 ° C., and the 70% by volume distillation temperature (T ₇₀ ) is preferably 200 ° C. or more and 265 ° C. or less, and 90% by volume distillation temperature (T ₉₀ ) is preferably 210 ° C. or more and less than 300 ° C., more preferably 210 ° C. or more and less than 295 ° C., and 95% by volume distillation temperature (T ₉₅ ) is preferably 220 ° C. or higher and 315 ° C. or lower, more preferably 220 ° C. or higher and 305 ° C. or lower, and most preferably 220 ° C. or higher and 300 ° C. or lower. The distillation end point (EP) is preferably 230 ° C. or higher and 330 ° C. or lower, more preferably 230 ° C. or higher and 310 or lower, and most preferably 230 ° C. or higher and 280 ° C. or lower.

If the 10% by volume distillation temperature (T ₁₀ ) is low, the flammability becomes high and evaporative gas (THC) is likely to be generated, causing a problem in handling. The upper limit values of the ₉₅ % by volume distillation temperature (T ₉₅ ) and the distillation end point (EP) are defined from the point that the amount of THC in the exhaust gas is small.

The distillation initial boiling point (IBP), 10 volume% distillation temperature _(T 10), 30 volume% distillation temperature _(T 30), 50 volume% distillation temperature _(T 50), 70 volume% distillation temperature ( T ₇₀ ), 90% by volume distillation temperature (T ₉₀ ), 95% by volume distillation temperature (T ₉₅ ), and end point (EP) are values measured by JIS K 2254 “Petroleum products-distillation 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, and so on, based on the total amount of fuel oil, it is 200 mass ppm or less, more preferably 100 mass ppm or less, and further preferably 80 mass ppm or less. More preferably, it is more preferably 20 ppm by mass or less, and the lower limit is not limited, but is preferably 0 ppm by mass.

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 smoke point of the fuel oil of the present invention is not limited, but is preferably 18 mm or more, and more preferably 21 mm or more. The smoke point is measured according to JIS K 2203.

There is no restriction | limiting in particular about the manufacturing method of the fuel oil of this invention. Specifically, for example, desulfurized kerosene obtained by desulfurizing a kerosene fraction obtained by distilling crude oil, desulfurized kerosene hydrotreated with desulfurized kerosene, low-sulfurized desulfurized hydrogenated kerosene, natural gas, etc. as carbon monoxide. Kerosene obtained by hydrodesulfurization and decomposition of “GTL (Gas to Liquids)” kerosene fraction (GTL kerosene), vacuum distillate, etc. obtained by FT (Fischer-Tropsch) synthesis after breaking down into hydrogen Equivalent fraction (hydrocracked kerosene), kerosene equivalent fraction obtained by catalytic cracking of residual oil / vacuum distillate (contact cracked kerosene), kerosene equivalent fraction obtained after direct desulfurization of heavy oil, residual oil, etc. It is produced using one or more hydrocarbon oils such as min (heavy oil direct desulfurized kerosene). Therefore, GTL kerosene compositions such as GTL kerosene and desulfurized kerosene, GTL kerosene and desulfurized hydrogenated kerosene can be used, and a kerosene composition consisting only of petroleum-based fuel such as a composition comprising desulfurized kerosene and hydrocracked kerosene can be used. Use is also possible.

Moreover, a gasoline base material can be added in the range which does not impair the summary of this invention as needed. Gasoline base materials include 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, light Desulfurized light naphtha desulfurized naphtha, desulfurized heavy naphtha desulfurized heavy naphtha, low olefins added to hydrocarbons such as isomerized gasoline and isobutane obtained by converting light naphtha to isoparaffin using an isomerizer ), The desulfurized alkylate obtained by desulfurizing the alkylate, the low-sulfur alkylate by desulfurized hydrocarbons such as isobutane and the desulfurized lower olefin, the reformed gasoline obtained by the catalytic reforming method, Raffinate (sulfolan raffinate), which is the residue of aromatics extracted from reformed gasoline. Light fraction of high quality gasoline (light reformed gasoline), medium heavy fraction of reformed gasoline (medium heavy reformed gasoline), heavy fraction of reformed gasoline (heavy reformed gasoline), catalytic cracking method Gasoline, hydrocracked gasoline, light fraction of cracked gasoline (light cracked gasoline), heavy fraction of cracked gasoline (heavy cracked gasoline), desulfurized cracked gasoline, cracked gasoline It is also possible to add desulfurized light cracked gasoline obtained by desulfurizing the light fraction, and desulfurized heavy cracked gasoline obtained by desulfurizing the heavy fraction of cracked gasoline. Of these, gasoline bases containing aromatic hydrocarbons are particularly preferred. For example, medium heavy fraction of reformed gasoline, heavy fraction of reformed gasoline, heavy fraction of cracked gasoline, desulfurized cracked gasoline. The treated desulfurized cracked gasoline and the desulfurized heavy cracked gasoline obtained by desulfurizing the heavy fraction of the cracked gasoline are preferred.

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 maintaining the cleanliness of the fuel line. You may add additives, such as a detergent and a lubricity improvement agent for lubrication improvement.

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 1-8
Using the amount (volume%) of the base material shown in Table 3, the fuel oil shown in Table 3 was produced. 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 200 ppm and THC emissions were 400 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 (6)

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 content of saturated hydrocarbons is 30% by volume or more, the content of olefinic hydrocarbons is 10% by volume or less, and the content of aromatic hydrocarbons is 65%. The fuel oil, wherein the fuel oil has a volume% or less, a naphthenic hydrocarbon content of 45 volume% or less, and an initial distillation point of distillation of 100 ° C. or more. The initial distillation point of distillation is 100 ° C. or more and 190 ° C. or less, the 10 vol% distillation temperature is 120 ° C. or more and 210 ° C. or less, the 95 vol% distillation temperature is 220 ° C. or more and 315 ° C. or less, and the end point is The fuel oil according to claim 1, which is 230 ° C or higher and 330 ° C or lower. The fuel oil according to claim 1 or 2, wherein the sulfur content is 200 mass ppm or less. The fuel oil according to any one of claims 1 to 3, comprising an oxygen-containing compound. 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 to 4. 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 fuel oil and a gas containing 65% by volume or more of oxygen, wherein the fuel oil is any one of claims 1 to 4. The diesel train in which the fuel oil according to claim 1 is used.

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