JP5317642B2 - Fuel composition for external combustion - Google Patents

Description

  The present invention relates to a fuel composition for external combustion, and more particularly, to a fuel composition for external combustion with a low number of unpleasant odors and soot emissions during ignition and extinguishing.

  External combustion fuel used in household combustion equipment such as stoves and water heaters, and heating and heating boilers in factories is prone to soot during ignition and extinguishing. There are concerns about the impact on the environment. In particular, in the use in highly airtight houses, and in the use of fuel in factories with houses in the vicinity, the use of fuel with less generation of unpleasant odor and soot at the time of ignition or extinguishing is required.

  In addition, so-called GTL (Gas to liquid) kerosene, which is made from natural gas as raw material and does not contain sulfur or aromatics produced by Fischer-Tropsch synthesis and is prepared in the same distillation characteristics as petroleum-based kerosene, is introduced to the market. ing. However, energy production is large for producing GTL kerosene, and both the production equipment cost and the operating cost are large, so the supply amount is expected to be limited for the time being. 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.

Thus, kerosene has been proposed that generates less soot during ignition and extinguishing (Patent Document 1). This proposes kerosene with less soot generation during combustion by setting not only the distillation properties but also the composition of paraffin and aromatics within a predetermined range. However, it does not pay attention to the number of soot particles discharged at the time of ignition or extinguishment, and the specific component of the fuel that affects the number of particles, and the smoke point is relatively high.
JP 2006-131710 A

  Therefore, an object of the present invention is to provide a fuel composition for external combustion that has a small number of soot emissions during ignition or extinguishing, has a smoke point within a specific range, and has extremely low sulfur.

  The present inventor has intensively studied to solve the above-mentioned problems. When preparing a fuel composition for external combustion, the content of a specific high-boiling component, particularly the content of a high-boiling bicyclic aroma or naphthalene. The number of soot emissions during ignition and fire extinguishing can be adjusted by adjusting the distillation properties so that is within a specific range, or by mixing highly refined low-aromatic kerosene fraction with petroleum-based commercial kerosene It was found that can be suppressed. The present invention has been completed based on such findings.

That is, this invention is the fuel composition for external combustion as follows.
(1) Sulfur content is 10 mass ppm or less, 50% distillation temperature is 160 to 210 ° C., 90% distillation temperature is 220 to 240 ° C., smoke point is 22 to 29 mm, total aroma content is 15 to 35% by volume, The total amount of bicyclic aroma and tetrahydronaphthalene is 15% by volume or less of the total amount of components other than paraffin (where tetrahydronaphthalene is the content of a compound having a 1,2,3,4-tetrahydronaphthalene skeleton) The fuel composition for external combustion which is an amount.).

(2) The fuel composition for external combustion according to (1), wherein the bicyclic aroma content is 0.1% by volume or less.
(3) The fuel composition for external combustion according to the above (1) or (2), wherein the total amount of 2-ring naphthene, 1-ring aroma and 1-ring naphthene is 35% by volume or more.

According to the fuel composition for external combustion of the present invention, since the content of the specific component is particularly limited to a specific range, there is an effect of suppressing the generation of soot during combustion. Furthermore, combustion of soot can be promoted, and the number of soot particles generated during ignition / extinguishing can be reduced. It promotes soot combustion and has the effect of reducing the number of soot particles generated during ignition and extinguishing.
Therefore, in the commercial kerosene fraction, the production of soot is reduced without blending expensive ones such as GTL kerosene, which is said to have a considerably small amount of soot mainly composed of paraffin components. A fuel composition 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, which is economical.

[Total sulfur content]
The fuel composition for external combustion of the present invention has a total sulfur content of 10 mass ppm or less. Since the total sulfur content is 10 ppm by mass or less, unpleasant odor and environmental load due to sulfurous acid gas and the like generated by combustion are reduced. The total sulfur content is preferably 5 ppm by mass or less, more preferably 3 ppm by mass or less, from the viewpoint of reducing environmental burden.

[50% distillation temperature]
The fuel composition for external combustion of the present invention has a 50% distillation temperature of 160 to 210 ° C. When the 50% distillation temperature is less than 160 ° C., the fuel consumption is deteriorated, and the odor emitted from the fuel composition during handling becomes strong. For this reason, the lower limit of the 50% distillation temperature is preferably 170 ° C. or higher, more preferably 190 ° C. or higher, particularly 195 ° C. or higher. On the other hand, if the 50% distillation temperature exceeds 210 ° C., the volatility deteriorates and the generation of unburned hydrocarbons and carbon monoxide increases. The upper limit of the 50% distillation temperature is preferably 205 ° C or lower, more preferably 200 ° C or lower, particularly 190 ° C or lower.

[90% distillation temperature]
The fuel composition for external combustion of the present invention has a 90% distillation temperature of 220 to 240 ° C. When the 90% distillation temperature exceeds 240 ° C., the combustibility is deteriorated and soot is easily generated. For this reason, it is preferably 235 ° C. or lower, more preferably 230 ° C. or lower. On the other hand, when the 90% distillation temperature is below 220 ° C., fuel efficiency is deteriorated. For this reason, the lower limit of the 90% distillation temperature is 220 ° C or higher, preferably 223 ° C or higher, more preferably 225 ° C or higher.

[Smoke point]
The fuel composition for external combustion of the present invention has a smoke point of 22 to 29 mm. If the smoke point is less than 22 mm, smoke is likely to be generated. Therefore, the smoke point is 22 mm or more, preferably 22.5 mm or more, more preferably 23 mm or more, and particularly 24 mm or more. Also, if the smoke point exceeds 29 mm, the length of the flame during combustion becomes longer, making it difficult to adjust the core with a core stove, or by hydrogenating an aromatic ring with a low smoke point. Because it is seen in overspecial fuel for external fuel prepared by using high naphthenic ring and paraffin, the energy cost at the time of production increases, and the difference between the product of the present invention and GTL kerosene becomes small. It is preferably 28 mm or less, more preferably 27 mm or less, and particularly 26 mm or less.

[For all aromas]
The total aroma content refers to the total content of 1-ring aroma, 2-ring aroma and tetrahydronaphthalene, and is 15 to 35% by volume. If the total aroma content is less than 15% by volume, the fuel consumption deteriorates. Further, since it takes enormous costs to reduce the total aromatic content by hydrogenation of aromatic rings or distillation separation, the lower limit of the total aroma content is 15% by volume or more, preferably 20% by volume or more, more preferably Is 22% by volume or more, particularly 25% by volume or more. On the other hand, if the total aromatic content exceeds 35% by volume, the combustibility deteriorates and soot is easily generated. For this reason, the upper limit of the total aroma content is 35% by volume or less, preferably 33% by volume or less, more preferably 31% by volume or less, and particularly 29% by volume or less.

[Tetrahydronaphthalene content]
The tetrahydronaphthalene content indicates the content of a compound having a 1,2,3,4-tetrahydronaphthalene skeleton, and is preferably 3.0 to 10.0% by volume. When the tetrahydronaphthalene content is less than 3.0% by volume, the fuel efficiency is deteriorated, and it is expensive to reduce the naphthene content by hydrocracking the naphthene ring adjacent to the aromatic ring or by aromatic cyclization. For this reason, the lower limit of the tetrahydronaphthalene content is 3.0% by volume or more, preferably 3.5% by volume or more, more preferably 4.0% by volume or more, and particularly 4.5% by volume or more. On the other hand, if the tetrahydronaphthalene content exceeds 10.0% by volume, the combustibility is deteriorated and soot is easily generated. For this reason, the upper limit of the tetrahydronaphthalene content is 10.0% by volume or less, preferably 9.0% by volume or less, more preferably 8.0% by volume or less, and particularly 7.5% by volume or less. Specific examples of the compound having a 1,2,3,4-tetrahydronaphthalene skeleton include tetralin, methyltetralin, dimethyltetralin, trimethyltetralin, indane, methylindane, dimethylindane, and trimethylindan.

[For 2-ring aroma]
The bicyclic aroma component is the content of a compound having a skeleton in which two benzene rings are condensed. For this reason, the bicyclic aroma content is preferably 0.1% by volume or less, most preferably not contained. Specifically, as a compound having two benzene rings, naphthalene, a naphthalene derivative substituted with one or more alkyl groups (1 to 5 carbon atoms in total), and one anthracene ring were saturated. Compound etc. are mentioned.

[The ratio of the total amount of paraffin, bicyclic aroma and tetrahydronaphthalene to the total amount of components excluding paraffin]
The paraffin content is preferably 20 to 70% by volume. When the amount of paraffin is small, wrinkles are likely to be generated, so the content is preferably 20% by volume or more, more preferably 30% by volume or more. In addition, if the paraffin content is too large, a large amount of aromatic rings and naphthene rings are hydrocracked, resulting in an increase in production cost and deterioration in low-temperature fluidity. Therefore, it is preferably 70% by volume or less, more preferably 60% by volume or less. It is. The paraffin content is normal paraffin and isoparaffin content, but the generation of soot is less when the normal paraffin content is higher. Specifically, normal paraffin is a saturated linear hydrocarbon compound having 9 to 20 carbon atoms, and isoparaffin is an isomer thereof.
In addition, the occurrence of soot is less in the 2-ring naphthene content, 1-ring aroma content, and 1-ring naphthene content than the 2-ring aroma content and the tetrahydronaphthalene content. Examples of the bicyclic naphthene include compounds having a skeleton in which two 5- to 7-membered cycloalkanes are combined, and typically include decalin and alkyl-substituted products thereof. One ring includes a compound having a benzene skeleton, which is typically benzene and an alkyl-substituted product thereof.
In order to suppress the generation amount of soot, the ratio of the total amount of bicyclic aroma and tetrahydronaphthalene to the total amount of components excluding paraffin is 15% by volume or less, preferably 13% by volume or less, more preferably 12%. The capacity is less than%. In addition, if the ratio of the total amount of bicyclic aroma and tetrahydronaphthalene to the total amount of components excluding paraffin is too low, the fuel consumption deteriorates, and the naphthene ring adjacent to the aromatic ring is hydrocracked or aromatic cyclized. Since it takes cost to reduce the naphthene content due to the above, etc., it is preferably 5.0% by volume or more, and more preferably 7.0% by volume or more.

  The fuel composition for external combustion according to the present invention is distilled as a raw material oil, for example, a kerosene fraction obtained from an atmospheric distillation apparatus, a catalytic cracking apparatus, a thermal cracking apparatus, or the like, that is, a boiling point of 140 to 280 ° C. It is obtained by hydrodesulfurization using a fraction, but in order to suppress the bicyclic aroma content, the feed oil that does not contain many of these compounds in the feed oil to be hydrodesulfurized, for example, oil obtained by pyrolyzing asphalt It is effective to reduce the mixing ratio or to select a raw material oil. 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 difficult desulfurization components, the catalyst which selectively removes a sulfur content is used in hydrodesulfurization. Examples of the catalyst that selectively removes a sulfur content include a CoMo catalyst and a NiMo catalyst.

Hydrodesulfurization uses one or more of Co, Mo, and Ni as a hydrodesulfurization catalyst, and optionally supports P, with a reaction temperature of 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 300 (± Fluctuations of about 5 are allowed.) Appropriate selection is made within the range of Nm ³ / kL so that the above-described fuel composition for external combustion of the present invention can be obtained. In particular, the LHSV, the hydrogen pressure, and the hydrogen / oil ratio should be 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 0.01 mass% or more of styrenes having 10 or more carbon atoms and dienes having 15 or more carbon atoms are contained, an antioxidant can be added to maintain good oxidation stability. Although the desired effect can be obtained with an addition amount of about 10 ppm by mass, 10 ppm by mass or more may be added.

  The antioxidant can be used without particular limitation among phenolic and amine-based ones. 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. Since 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, but in particular, vinyl acetate, vinyl propionate, Vinyl esters of saturated fatty acids such as vinyl butyrate are preferably used. As the wear resistance improver, for example, long chain fatty acids (carbon number 12 to 24) or fatty acid esters thereof are preferably used. The wear resistance is sufficiently improved by the addition amount of 10 to 500 ppm, preferably 50 to 100 ppm.

  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.

Preparation of test fuel (fuel composition for external combustion) The fuel composition for external combustion of the present invention was evaluated using the following test fuels 1 to 4.
Test fuel 1: Commercial kerosene (JIS No. 1 kerosene)
Test fuel 2: A mixture of 80% by volume of commercial kerosene of Test fuel 1 and 20% by volume of naphthenic solvent (manufactured by NOF Corporation, naphthenic solvent D40).
Test fuel 3: A fraction having a boiling range of 150 to 268 ° C. distilled from an atmospheric distillation apparatus was used with a commercial catalyst supporting Co, Mo, P, a reaction temperature of 350 ° C., a reaction pressure of 7.2 MPa, hydrogen / A hydrorefined oil obtained under conditions of an oil ratio of 300 ± 5 Nm ^{3 /} kL, LHSV 1.0 h ⁻¹ , and hydrogen purity 94%.
Test fuel 4: A distillate having a boiling range of 145 to 250 ° C. distilled from an atmospheric distillation apparatus was used with a commercial catalyst supporting Co, Mo, P, a reaction temperature of 350 ° C., a reaction pressure of 10 MPa, and a hydrogen / oil ratio. A raffinate obtained by hydrotreating under conditions of 300 ± 5 Nm ^{3 /} kL, LHSV 1.0 h ⁻¹ , hydrogen purity 94%, and then separating normal paraffin with a zeolite catalyst having a pore diameter of 5 mm.

  About said test fuel 1-4, each physical property and a component composition were measured, and also the combustion test by a petroleum stove was performed, and evaluation was performed from the particle | grain number etc. of the soot contained in the combustion exhaust gas. The results are shown in Table 1.

Measurement methods and evaluation methods such as physical properties, component compositions, and combustion exhaust gas evaluation described in Table 1 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) Sulfur content: A method defined in JIS K2541-6 “Sulfur content test method (ultraviolet fluorescence method)”.
4) Smoke point: A method defined in JIS K2537 “Smoke point test method”.
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5) Detailed components such as total aroma, bicyclic aroma, tetrahydronaphthalene, paraffin and other components: GC with HP-6890N FID detector manufactured by Agilent Technologies, and AccuTOF JMS-T100GC flight time manufactured by JEOL Ltd. A GC system with a type mass spectrometer was used. Detailed analysis conditions are as follows.
Primary column: Micropolar column (PTE-5 manufactured by Supelco, length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm), modulator hollow column: length 2 m, inner diameter 0.1 mm
Secondary column: High-polarity column (SpelcoWAX10 from Supelco, length 2 m, inner diameter 0.25 mm, film thickness 0.25 μm)
Temperature rising condition: 10 ° C./min (from 50 ° C. (5 min hold) to 280 ° C. (27 min hold))
Inlet temperature: 280 ° C
Injection volume: 1.0 μl
Split ratio: 100: 1
Carrier gas: helium (He), 1.0 ml / min Modulator temperature: The following cold temperature and hot temperature are repeated.
Hot jet gas temperature: The temperature was raised from 150 ° C. (5 minutes hold) to 320 ° C. (33 minutes hold) at 10 ° C./min.
Cold jet gas temperature: about -140 ° C
Modulator frequency: 6 seconds for 0.3 seconds hot temperature, then 5.7 seconds for cold temperature.
Interface hollow column: 0.5m length, 0.25mm inner diameter
FID gas conditions: hydrogen (45 mL / min), air (450 mL / min), make-up helium (25 mL / min)
This GC system can measure a compound having 7 to 44 carbon atoms, and identifies a compound corresponding to each peak (yamagata) from the elution time and mass spectrum of the measured peak (yamagata). The sum of all identified peaks (yamagata) is defined as the total content (100 peak volume%), and the content of each corresponding compound is calculated as the peak volume% from each peak (yamagata). To do. The identified compounds are classified into the above components (compound groups) by skeleton, and the content for each classified component is determined.

6) The number and size of soot particles in the combustion exhaust gas:
Using a commercially available core-type stove (natural aeration type open petroleum stove made by Sharp HSR-26L), the number of soot particles contained in the generated flue gas (integrated value of the number of soot particles) and the maximum value of soot particle diameter Was measured and evaluated under the following conditions.
For the sampling of combustion exhaust gas, the combustion exhaust gas was collected and sampled by a 20 cm square hood installed 5 cm above the top plate of the oil stove, and the exhaust gas sample was directly supplied to the particle diameter and particle number measuring device through a duct connected to the hood. .
At the beginning of the ignition head, set the height of the lead with the lever so that it is one level below the maximum scale (80% of the maximum height of the lead). The height was adjusted. 2 minutes after ignition, the earthquake-resistant automatic fire extinguishing device was activated to extinguish the fire instantaneously. During the period from ignition to 30 seconds after extinguishing, exhaust gas samples were continuously taken (total 2 minutes 30 seconds).
Measurement of particle size and number of particles: Combustion exhaust gas collected in the hood is supplied through a duct to a real-time self-draining particle analyzer (EEPS 3090 manufactured by Tokyo Direc Co., Ltd.) at a rate of 10 L / min for 2 minutes and 30 seconds every second. All the particles were counted, and the total number of particles (integrated value of the number of soot particles) and the maximum value of the number of soot particles, that is, the maximum value (peak value) of the number of soots that passed in 1 second were obtained. In Table 1, the integrated value of the number of soot particles and the maximum value of the number of soot particles are shown as a ratio with respect to the value of the test fuel 1 as a reference (1.0).

  From Table 1, the test fuel 2 has the same maximum number of soot particles as the test fuel 1, but the soot particle integrated value is high, and the test fuel 3 has the soot particle integrated value. It can be seen that both the maximum values are good. In addition, the sample fuel 4 has the same number of soot particles as the sample fuel 1, but the maximum value is good.

Claims (2)

Total sulfur content is 10 mass ppm or less, 50% distillation temperature is 160-210 ° C, 90% distillation temperature is 220-240 ° C, smoke point is 22-29mm, total aroma content is 15-35% by volume, two rings The total amount of aroma and tetrahydronaphthalene is 10% by volume or more and 15% by volume or less of the total amount of components other than paraffin (where tetrahydronaphthalene is a compound having a 1,2,3,4-tetrahydronaphthalene skeleton) The total amount of 2-ring naphthene, 1-ring aroma, and 1-ring naphthene is 35% by volume or more . Furthermore, the fuel composition for external combustion of Claim 1 whose bicyclic aroma content is 0.1 volume% or less.