JP5279478B2 - Fuel composition for external combustion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel composition for external combustion, whose discharge amount of soot or nitrogen oxide is small and which has a low content of sulfur. <P>SOLUTION: The fuel composition has a density (15&deg;C) of 0.83-0.87 g/cm<SP>3</SP>, a 90% distillation temperature of 330-365&deg;C, a kinematic viscosity (30&deg;C) of 7.2 mm<SP>2</SP>/s or lower, a total sulfur content of 0.50 mass% or lower, a total nitrogen content of 300 mass ppm or lower, a total aromatic content of 25-35 vol.%, an aniline point of 60.0-80.0&deg;C, a water content of 120 mass ppm or lower, and a cetane index (JIS-2280) of 47-65. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a fuel composition for external combustion, and particularly relates to a fuel composition for external combustion that emits less soot and nitrogen oxides.

  Fuel for external combustion used in external combustion engines such as heating boilers and heating boilers in factories tends to generate soot, and nitrogen oxides are generated during combustion. Reducing the generation amount is preferable from the viewpoint of health and environmental load.

  On the other hand, as a fuel for external combustion, natural gas is used as a raw material, and so-called GTL (prepared by distillation properties equivalent to petroleum-based kerosene, which does not contain sulfur or aromatics produced by Fischer-Tropsch synthesis, is prepared. Gas to liquid) may be used, but in order to produce GTL fuel, energy consumption is large and production equipment costs and operation costs are both high, so the supply amount is limited for the time being. Expected. For this reason, it is desired to improve the quality of petroleum-based fuels that are relatively inexpensive and produced and supplied in large quantities.

On the other hand, in order to reduce soot emissions when used as a fuel for internal combustion engines such as diesel engines, it is known to add fatty acid alkyl esters obtained by esterifying fats and oils such as animal oils and vegetable oils to heavy oil A. (See Patent Document 1 below). However, these fatty acid alkyl esters have a high raw material procurement cost, and the supply amount is limited for the time being.
JP 2007-231119 A

  Then, this invention makes it a subject to provide the fuel composition for external combustion which has little discharge | emission amount of soot and nitrogen oxide, and is also very low sulfur.

  The present inventor has intensively studied to solve the above-mentioned problems. When preparing a fuel composition for external combustion, the petroleum-based commercial heavy fuel oil A has a specific property so that physical properties and chemical properties are in a specific range. It has been found that the amount of soot and nitrogen oxides discharged can be suppressed by mixing the paraffin component, and the present invention has been completed based on this finding.

That is, the fuel composition for external combustion of the present invention has a density (15 ° C.) of 0.83 to 0.87 g / cm ³ , a 90% distillation temperature of 330 to 365 ° C., and a kinematic viscosity (30 ° C.) of 7. 2 mm ² / s or less, total sulfur content is 0.50 mass% or less, total nitrogen content is 300 mass ppm or less, total aromatic content is 25 to 35% by volume, aniline point is 60.0 to 80.0 ° C., moisture Is 120 mass ppm or less, and the cetane index (JIS-2280) is 47 to 65.

  In the fuel composition for external combustion according to the present invention, the bicyclic aromatic content is preferably 6.0% by volume or less, and the tricyclic aromatic content is preferably 4.0% by volume or less.

  According to the fuel composition for external combustion of the present invention, since the content of the specific component is limited to a specific range, the effect of suppressing the emission of soot and nitrogen oxides during combustion is exhibited. . Therefore, according to the present invention, the emission of soot and nitrogen oxides is reduced without blending expensive base materials such as GTL kerosene and fatty acid alkyl esters, which are said to produce considerably less smoke. The prepared fuel composition for external combustion can be prepared. As a result, the cost of expensive production equipment for producing GTL kerosene and the enormous energy consumption required for operation can be saved, and fatty acid alkyl esters with high raw material procurement costs are not used. Is economical.

  In addition, for example, in a house warmer for external combustion equipment, smoke in the exhaust gas accumulates over a long period of operation on the wall surface of the can body through which the exhaust gas after combustion passes, reducing heat transfer efficiency, Since it is necessary to periodically clean the inside of the boiler, it is preferable that the smoke in the exhaust gas is small from the viewpoint of environmental load. However, according to the fuel composition for external combustion of the present invention, the amount of smoke discharged is small. In addition to reducing the environmental load, it is also possible to reduce the frequency of periodic cleaning inside the boiler while suppressing a decrease in combustion efficiency.

〔density〕
The fuel composition for external combustion of the present invention has a density of 0.83 to 0.87 g / cm ³ . When the density of the fuel composition is high, the calorific value per volume increases and the combustion temperature rises, so that the amount of nitrogen oxide emissions increases. For this reason, the density of the fuel composition for external combustion of the present invention is 0.87 g / cm ³ or less, preferably 0.86 g / cm ³ or less, more preferably, from the viewpoint of suppressing the emission amount of nitrogen oxides. Is 0.85 g / cm ³ or less. Meanwhile, since the fuel consumption when the density of the fuel composition is too low to deteriorate, the density of the outer燃用fuel composition of the present invention is 0.83 g / cm ³ or more, preferably 0.84 g / cm ³ or more is there.

[90% distillation temperature]
The fuel composition for external combustion of the present invention has a 90% distillation temperature of 330 to 365 ° C. If the 90% distillation temperature is too high, the combustibility deteriorates and soot and nitrogen oxides are likely to be generated. For this reason, the 90% distillation temperature of the fuel composition for external combustion of the present invention is 365 ° C. or lower, preferably 360 ° C. or lower, more preferably 355 ° C. or lower. On the other hand, if the 90% distillation temperature is too low, the fuel efficiency is deteriorated. For this reason, the 90% distillation temperature of the fuel composition for external combustion of the present invention is 330 ° C. or higher, preferably 340 ° C. or higher, more preferably 350 ° C. or higher, particularly 355 ° C. or higher.

[Kinematic viscosity (30 ° C)]
The fuel composition for external combustion of the present invention has a kinematic viscosity (30 ° C.) of 7.2 mm ² / s or less. If the kinematic viscosity at 30 ° C. is high, the fuel particle size at the time of fuel spray becomes large, and soot is likely to be generated due to deterioration in volatility and deterioration in mixing with air. For this reason, the kinematic viscosity (30 ° C.) of the fuel composition for external combustion of the present invention is 7.2 mm ² / s or less, preferably 7.0 mm ² / s or less, more preferably 6.0 mm ² / s or less, In particular, it is 5.0 mm ² / s or less. In the fuel composition for external combustion of the present invention, the lower limit of the kinematic viscosity (30 ° C.) is not particularly limited, but usually the kinematic viscosity (in order to maintain the penetration force of the fuel spray and suppress the deterioration of the fuel consumption) 30 ° C.) is preferably 3.0 mm ² / s or more, more preferably 4.0 mm ² / s or more.

〔moisture〕
The fuel composition for external combustion according to the present invention has a water content of 120 mass ppm or less. If the moisture is too high, the moisture in the oil is easily released due to a decrease in the outside air temperature, the free water freezes, and the filter for filtration installed in the fuel supply system is clogged. Occurs to form sludge, and the frequency of replacement of the filter for filtration increases. For this reason, the fuel composition for external combustion of the present invention has a water content of 120 mass ppm or less, preferably 100 mass ppm or less, more preferably 80 mass ppm or less, particularly 70 mass ppm or less.

[Cetane index]
The fuel composition for external combustion of the present invention has a cetane index of 47 to 65. If the cetane index is too low, the ignitability at low temperatures deteriorates, and the amount of nitrogen oxides increases due to rapid ignition and high combustion temperature, so the fuel composition for external combustion of the present invention The cetane index is 47 or more, preferably 50 or more, more preferably 53 or more, and particularly 55 or more. In addition, if the cetane index is too high, the length of the flame of diffusion combustion becomes long and local high temperature spots are likely to be formed. Therefore, the cetane index of the fuel composition for external combustion of the present invention is 65 or less, preferably Is 60 or less, more preferably 58 or less.

[Total sulfur content]
The fuel composition for external combustion of the present invention has a total sulfur content of 0.50% by mass or less. Since the fuel composition for external combustion of the present invention has a total sulfur content of 0.50% by mass or less, an unpleasant odor and an environmental load due to sulfurous acid gas and the like generated by combustion are reduced. The total sulfur content of the fuel composition for external combustion of the present invention is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, particularly 0.10% by mass, from the viewpoint of reducing the environmental load. It is as follows.

[Total nitrogen content]
The fuel composition for external combustion of the present invention has a total nitrogen content of 300 mass ppm or less. Since the fuel composition for external combustion of the present invention has a total nitrogen content of 300 ppm by mass or less, the amount of nitrogen oxide generated by combustion is small, and the environmental load is reduced. In addition, the total nitrogen content of the fuel composition for external combustion of the present invention is preferably 250 ppm by mass or less, more preferably 220 ppm by mass or less, particularly 210 ppm by mass or less, from the viewpoint of reducing the environmental load.

[Total aromatic content]
The fuel composition for external combustion of the present invention has a total aromatic content of 25 to 35% by volume. If the total aromatic content is too low, the fuel consumption increases, so the fuel composition for external combustion of the present invention has a total aromatic content of 25% by volume or more, preferably 28% by volume or more, more preferably 30%. It is more than volume%. On the other hand, if the total aromatic content is too high, the oxidation reaction rate becomes slow and soot is easily generated. Therefore, the fuel composition for external combustion of the present invention has a total aromatic content of 35% by volume or less, preferably 33% by volume or less.

[Bicyclic aromatic component]
The fuel composition for external combustion of the present invention preferably has a bicyclic aromatic content of 6.0% by volume or less. Here, the bicyclic aromatic component is the content of a compound having two benzene rings, and the benzene rings may be condensed with each other. If the bicyclic aromatic content is too high, the oxidation reaction rate becomes slow and soot is easily generated. Therefore, the bicyclic aromatic content of the fuel composition for external combustion of the present invention is preferably 6.0% by volume or less. Yes, more preferably 5.7% by volume or less, still more preferably 5.5% by volume or less.

[Tricyclic aromatic component]
The fuel composition for external combustion of the present invention preferably has a tricyclic aromatic content of 4.0% by volume or less. Here, the tricyclic aromatic component is the content of a compound having three benzene rings, and a plurality of benzene rings may be condensed. If the tricyclic aromatic content is too high, the oxidation reaction rate becomes slow and soot is easily generated. Therefore, the tricyclic aromatic content of the fuel composition for external combustion of the present invention is preferably 4.0% by volume or less. Yes, more preferably 3.0% by volume or less, still more preferably 2.0% by volume or less.

[Aniline point]
The fuel composition for external combustion of the present invention has an aniline point of 60.0 to 80.0 ° C. If the aniline point is too low, the number of aromatic rings increases, the combustibility deteriorates and smoke is likely to be generated, so the aniline point of the fuel composition for external combustion of the present invention is 60.0 ° C. or higher. The temperature is preferably 65.0 ° C. or higher, more preferably 66.0 ° C. or higher, particularly 67.0 ° C. or higher. On the other hand, if the aniline point is too high, the length of the flame becomes longer due to an increase in the paraffin content, the temperature distribution in the combustion chamber becomes easier, the heat generation amount decreases, and the heat of the external combustion engine such as a boiler. Since the transmission efficiency is deteriorated, the aniline point of the fuel composition for external combustion of the present invention is 80.0 ° C. or lower, preferably 78.0 ° C. or lower, more preferably 75.0 ° C. or lower, especially 73. 0 ° C. or lower.

[Production method of fuel composition for external combustion]
The fuel composition for external combustion of the present invention is not particularly limited in the production method, but as a raw material oil, for example, a kerosene oil fraction obtained from an atmospheric distillation device, a catalytic cracking device, a thermal cracking device, or the like, that is, a boiling point of 140. It can be obtained by adding bottom oil of an atmospheric distillation apparatus as a residual coal modifier to hydrodesulfurization using a fraction distilled in a range of ˜360 ° C. In addition, in order to suppress the bicyclic aromatic component and tricyclic aromatic component, the mixing ratio of the raw oil containing many of these compounds to the raw oil to be hydrodesulfurized, for example, the oil obtained by pyrolyzing asphalt, It is effective to make a selection. In order to suppress the content of these compounds, it is also effective to distill and separate the high boiling point side of the raw material oil, increase the reaction temperature, increase the hydrogen partial pressure, or increase the hydrogen / oil ratio. . In addition, since the kerosene fraction obtained from a catalytic cracking apparatus, a thermal cracking apparatus, etc. also contains many non-desulfurization components, it is preferable to use a catalyst that selectively removes sulfur in hydrodesulfurization. Here, examples of the catalyst for selectively removing the sulfur content include a CoMo catalyst and a NiMo catalyst.

In the above hydrodesulfurization, for example, a hydrodesulfurization catalyst containing one or more of Co, Mo and Ni and optionally carrying P is used, and the reaction temperature is 270 to 380 ° C., preferably 295 to 360. ° C, reaction pressure 2.5 to 8.5 MPa, preferably 2.7 to 7.0 MPa, LHSV 0.9 to 6.0 h ⁻¹ , preferably 0.9 to 5.4 h ⁻¹ , hydrogen / oil ratio 130 to The fuel composition for external combustion of the present invention described above is obtained by appropriately selecting within the range of 300 (with a variation of about ± 5 allowed) Nm ³ / kL. In particular, it is preferable that the LHSV, the hydrogen pressure, and the hydrogen / oil ratio are large. The reaction temperature is preferably lowered in order to suppress the formation of styrene compounds and diene compounds having poor oxidation stability.

  Any antioxidant known to those skilled in the art can be added to the fuel composition for external combustion according to the present invention as necessary. When an antioxidant is added, the amount added can be appropriately adjusted by those skilled in the art according to the target oxidation stability. For example, when the fuel composition contains 0.01% by mass or more of styrenes having 10 or more carbon atoms and dienes having 15 or more carbon atoms, an antioxidant may be added to maintain good oxidation stability. The desired effect can be obtained with an addition amount of about 1 to 10 ppm by mass, but 10 ppm by mass or more may be added.

  As said antioxidant, it can use without a restriction | limiting in particular among a phenolic antioxidant and an amine antioxidant. Specifically, 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 2,4-dimethyl-6-t-butylphenol, 2,4,6-tri- phenolic antioxidants such as t-butylphenol, 2-t-butyl-4,6-dimethylphenol, 2-t-butylphenol, N, N′-diisopropyl-p-phenylenediamine, N, N′-di- Examples thereof include amine-based antioxidants such as sec-butyl-p-phenylenediamine, and mixtures thereof. In addition to phenolic and amine compounds, substances with an antioxidative effect are conceivable, but for the sake of clarity, in the present invention, only phenolic and amine compounds are treated as antioxidants to prevent oxidation. When other compounds having an effect are added, they are handled as fuel base materials.

  In addition, known fuel additives such as a low-temperature fluidity improver, an abrasion resistance improver, and a cetane number improver may be added. In addition, since the fuel composition for external combustion of the present invention has good low temperature fluidity, it is not necessary to add a low temperature fluidity improver, but when it is added, an ethylene copolymer or the like can be used. Are preferably vinyl esters of saturated fatty acids such as vinyl acetate, vinyl propionate and vinyl butyrate. In addition, as the wear resistance improver, for example, a long-chain fatty acid (12 to 24 carbon atoms) or a fatty acid ester thereof is preferably used, and the wear resistance is sufficiently improved with an addition amount of 10 to 500 ppm, preferably 50 to 100 ppm. To do.

  Hereinafter, the fuel composition for external combustion of the present invention will be specifically described with reference to examples. In addition, although this invention is realizable if it implements like the following examples, it is not limited to a present Example. Moreover, when producing for A heavy oil, it cannot be overemphasized that the coumarin of the light oil discriminating agent obliged to add predetermined amount is added so that it may become predetermined amount.

<Preparation of test fuel (fuel composition for external combustion)>
-Test fuel 1: Commercial A heavy oil-Test fuel 2: 75% by volume of commercial A heavy oil of test fuel 1 and a fraction having a boiling point range of 170-360 ° C distilled from the atmospheric distillation apparatus were dewaxed catalyst After removing wax using a commercially available catalyst supporting Co, Mo, P, reaction temperature 350 ° C., reaction pressure 7.2 MPa, hydrogen / oil ratio 300 ± 5 Nm ³ / kL, LHSV 1.0 h ⁻¹ , It was obtained by mixing 25% by volume of hydrorefined oil obtained by hydrorefining under the condition of 94% hydrogen purity.
Test fuel 3: 75% by volume of test fuel 1 and a fraction having a boiling range of 145 to 270 ° C. distilled from an atmospheric distillation apparatus, using a commercially available catalyst supporting Co, Mo, P, reaction temperature 350 After hydrorefining under conditions of ℃, reaction pressure 10MPa, hydrogen / oil ratio 300 ± 5Nm ³ / kL, LHSV 1.0h ^-1 , hydrogen purity 94%, after separation of normal paraffin with zeolite catalyst with pore size of 5mm It was obtained by mixing 25% by volume of normal paraffin having a carbon number of 14 or more and a boiling point of 250 to 270 ° C. obtained by distillation separation.
Test fuel 4: The test fuel 1 was obtained by mixing 25% by volume, 75% by volume of normal paraffin having a carbon number of 14 or more and a boiling point of 250 to 270 ° C. Therefore, the test fuel 4 has a normal paraffin content of 50% by volume higher than that of the test fuel 3.
Test fuel 5: obtained by mixing 75% by volume of test fuel 1 and 25% by volume of a commercially available isoparaffin solvent (NAS-5H).

<Test equipment (house heating machine)>
・ Manufacturer: Nepon Corporation
・ Model: HK3025TE
・ Output: 87.2kW
・ Hydraulic pressure: 1.03 MPa
・ Fuel maximum flow rate: 9.7 L / hour

  For each of the above test fuels 1, 2, 3, and 5, the physical properties and composition of the components are measured, and further, a combustion test is performed with a house warmer, the amount of soot contained in the combustion exhaust gas, nitrogen oxidation Evaluation was made from the amount of waste discharged. The results are shown in Table 1. Table 2 shows the results of the combustion efficiency for the test fuels 3 and 4.

Measurement methods and evaluation methods such as physical properties, component compositions, and combustion exhaust gas evaluation described in Tables 1 and 2 were measured and evaluated by the following methods.
1) Density: The method specified in JIS K2249 “Crude oil and petroleum product density test method”.
2) Distillation property: A method defined in JIS K2254 “Distillation Test Method”.
3) Kinematic viscosity: A method defined in JIS K2283 “Kinematic viscosity test method”.
4) Cetane index: A method defined in JIS K2280 “Method for calculating cetane index”.
5) Total sulfur content: A method defined in JIS K2541-6 “Sulfur content test method (ultraviolet fluorescence method)”.
6) Total nitrogen content: A method defined in JIS K2609 “Method for testing nitrogen content”.
7) Moisture: “Karl Fischer-type coulometric titration method” defined in JIS K2275 “Moisture test method”.
8) Total calorific value: The method defined in JIS K2279 “Testing method of calorific value and estimation method by calculation”.
9) Total aromatics, 1-ring aromatics, 2-rings aromatics, 3-rings aromatics: Petroleum Society method JPI-5S-49-97 “Petroleum products—Hydrocarbon type test method—High performance liquid chromatograph method” ”Method.
10) Aniline point: A method defined in JIS K2256 “Petroleum products—Test method for aniline point and mixed aniline point”.

<Combustion test method>
An exhaust gas sampling port is attached to the nearest flue from the can body, and the air shutter opening degree for controlling the amount of combustion air is 5 to 7 points (each opening degree is 55% by measuring the length of the opening from the fully opened state) The smoke is sampled with exhaust gas (O ₂ , CO, CO ₂ and NOx) and baccarax smoke tester (abbreviated as smoke tester). Each time the air shutter opening is changed while checking the O ₂ concentration and smoke concentration in the exhaust gas. In general, as the air shutter opening is reduced, the amount of combustion air decreases and the efficiency increases, but the smoke increases and increases more rapidly than a certain amount of air.

<Combustion exhaust gas analyzer specifications>
・ Name: Combustion exhaust gas analyzer ・ Manufacturer name: Hodaka Co., Ltd. ・ Model: HT-1600N
・ Measurement items: O ₂ , CO, CO ₂ , NOx (constant potential electrolysis method)
Exhaust gas temperature, pressure, combustion efficiency

<Smoke concentration meter and measurement method>
-Name: Baccarat Smoke Tester-Manufacturer Name: Hodaka Co., Ltd.-Model: HT-1650
・ Measurement item: Smoke (according to ASTM D-2156-95)
・ Measurement method: According to the manufacturer's instructions, the handle is manually moved about 10 times to suck the exhaust gas, and the color adhering to the preset white filter paper is the color of the predetermined scale (10 levels: clean 0-9 contamination) And the density (frequency) is determined.

From Table 1, when the oxygen (O ₂ ) concentration in the exhaust gas is constant at 3%, compared with Comparative Example 1, Examples 1 and 2 have both lower smoke concentration and nitrogen oxide emission at the same time. Indicated. In Comparative Example 2, the smoke concentration was lower than those in Examples 1 and 2, but the nitrogen oxide emissions were high.

Further, when the oxygen (O ₂ ) concentration in the exhaust gas is constant at 4% and when it is constant at 5%, Comparative Examples 1 and 2 have the same smoke concentration as Examples 1 and 2, but Example 1 Compared with 2 and 2, the nitrogen oxide emission amount was high.

  Further, since the air shutter opening is generally used at a constant rate, an experiment was conducted with a constant air shutter opening with particular emphasis on the smoke density. When the air shutter opening was 55%, Comparative Example 1 and Compared to 2, Examples 1 and 2 had a lower smoke concentration. In addition, about nitrogen oxide discharge, although Example 1 is higher than Comparative Examples 1 and 2, since smoke concentration is significantly lower than Comparative Examples 1 and 2, Example 1 is better for comprehensive evaluation. . Further, in Example 2, the nitrogen oxide emission amount is intermediate between Comparative Example 1 and Comparative Example 2, but the smoke emission amount is low and the overall evaluation is good.

  In addition, when the air shutter opening degree is 4% and 5%, the smoke concentration of Examples 1 and 2 is equal to or less than that of Comparative Examples 1 and 2, and the amount of nitrogen oxide emission is low. The overall evaluation of 1 and 2 is good.

  Therefore, when the air shutter opening degree is constant, Examples 1 and 2 are good in low smoke density in actual use.

  In addition, Table 2 shows that Example 1 has higher combustion efficiency than Comparative Example 3. Since Comparative Example 3 has a larger amount of normal paraffin mixture than Example 1, it can be seen that if the amount of normal paraffin mixture is too large, the combustion efficiency decreases.

Claims (2)

The density (15 ° C.) is 0.83 to 0.87 g / cm ³ , the 90% distillation temperature is 330 to 365 ° C., the kinematic viscosity (30 ° C.) is 7.2 mm ² / s or less, and the total sulfur content is 0.50. Mass% or less, total nitrogen content is 300 mass ppm or less, total aromatic content is 25 to 35% by volume, aniline point is 60.0 to 80.0 ° C., moisture is 120 mass ppm or less, cetane index (JIS-2280) Is a fuel composition for external combustion, characterized by being 47-65.   The fuel composition for external combustion according to claim 1, wherein the bicyclic aromatic component is 6.0 vol% or less and the tricyclic aromatic component is 4.0 vol% or less.