JP2014156533A - Production method of light oil base, and light oil composition containing the base - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a light oil base, in which sludge or deposits are rarely produced and oxidation stability is secured, using a decomposed light oil having poor oxidation stability as a raw material component, and to provide a light oil composition containing the light oil base.SOLUTION: In a production method of a light oil base, a mixed oil composed of 2 to 25 vol.% of a decomposed light oil having 5 to 35 vol.% of the content of a bicyclic aromatic component and 75 to 98 vol.% of a straight-run light oil is hydrodesulfurizated, thereby obtaining a light oil base having 8.5 to 15.5% of the content (ionic strength%) of one ring naphteno benzenes and two ring naphteno benzenes, 70 minutes or more of the induction period and 51 or more of the cetane number.

Description

  The present invention relates to a method for producing a light oil base material having ensured oxidation stability, characterized in that cracked light oil and straight run light oil are mixed and hydrodesulfurized. Furthermore, it is related with the light oil composition characterized by mix | blending the light oil base material and kerosene base material which were manufactured by the said method.

Light oil fuels used in diesel engines are not limited to conventional straight-run middle distillates as the demand for heavy oil fuels has declined in recent years, but also cracking systems obtained from hydrocracking equipment and fluid catalytic cracking equipment. Increase in light oil base materials, increase in natural gas, asphalt, coal, etc. as raw materials, increase in synthetic light oil base materials obtained by chemical synthesis, increase in biomass-derived base materials from the viewpoint of reducing CO2 emissions, etc. It is expected to diversify.
However, since light oil feedstocks other than conventional straight-run middle distillates, especially cracking systems, are obtained by treating heavy components of straight-run systems in a high-temperature and high-pressure environment, they are unstable substances in the product oil. Are likely to be produced, and stability is often deteriorated.

  On the other hand, diesel engines are becoming more demanding to improve the oxidation stability of diesel oil than ever before due to the increased pressure of fuel injection by the common rail due to stricter exhaust gas regulations, increasing the thermal load on diesel oil. Thus, in order to improve the oxidation stability of light oil, for example, it is conceivable to add an antioxidant additive, and it is proposed to add an antioxidant to light oil whose sulfur content is reduced to 10 mass ppm or less. (See Patent Document 1). A method of adding kerosene to which an antioxidant is added to light oil is also conceivable. However, the method of adding an antioxidant additive varies the additive effect of the additive due to the change in the composition of the light oil at the time of manufacture. . Moreover, when an additive is added excessively, it will become easy to precipitate an additive by temperature fall. In addition, if the additive amount is too small, after the antioxidant effect of the additive is exhausted during oxidation, the oxidation stability of the light oil will be significantly deteriorated, causing adverse effects such as engine cleanliness and corrosion of metal materials. . In addition, it has been proposed to maintain oxidation stability without adding an antioxidant additive by setting the content of aromatic components and naphthene components in light oil within a specific range (see Patent Document 2). Although this method of preparing a light oil composition is effective, the invention described in Patent Document 2 focuses on fluorenes and naphthenobenzenes as substances having poor oxidative stability, and is a substance having good content and oxidative stability. It is balanced with the naphthalene content. However, when hydrocracking a cracked light oil base material in a high-temperature and high-pressure environment, naphthenobenzenes with poor oxidation stability are likely to be produced in the product oil. In the invention described in Patent Document 2, naphthenobenzenes are There is no mention of a method for preparing a light oil composition when present in high concentration.

JP 2004-225000 A JP 2006-137922 A

  An object of the present invention is to provide a light oil base material that ensures oxidation stability in which sludge and deposits are not easily generated by appropriately mixing a cracked light oil raw material having poor oxidation stability and a straight-run gas oil raw material, and performing hydrodesulfurization treatment. Is to manufacture. Furthermore, an object of the present invention is to provide a light oil composition that maintains good oxidation stability without adding an additive for antioxidants by mixing the obtained light oil base and kerosene base. .

  As a result of diligent research, the inventor of the present invention appropriately mixed a cracked gas oil feedstock having poor oxidation stability and a straight-run gas oil feedstock having good oxidation stability in a specific property range, and hydrotreating them. It has been found that a light oil base material in which the content of nobenzenes is limited within a specific ratio range is produced, and good oxidation stability is ensured. In addition, by securing this good oxidation stability, it was found that the oxidation stability can be improved without mixing a lot of kerosene base materials having good oxidation stability and without adding an antioxidant, and the present invention is completed. It came to.

  That is, in the present invention, hydrodesulfurization treatment is performed on a mixed oil composed of 2 to 25% by volume of cracked gas oil having a bicyclic aromatic content of 5 to 35% by volume and 75 to 98% by volume of straight-run gas oil. Gas oil characterized in that a gas oil base having a ring + bicyclic naphthenobenzene content (ionic strength%) of 8.5 to 15.5%, an induction period of 70 minutes or more, and a cetane number of 51 or more is obtained. The present invention relates to a method for manufacturing a substrate.

  Moreover, the present invention has a 10% by volume distillation temperature of cracked light oil of 200 ° C. to 250 ° C., a 90% by volume distillation temperature of 335 ° C. to 360 ° C. and a cetane index of 29 to 35, % Distillation temperature is 230 ° C. to 285 ° C., and 90 vol% distillation temperature is 340 ° C. to 370 ° C.

The present invention also provides a reaction temperature of 310 ° C. to 395 ° C., LHSV of 0.5 to 2 hr ⁻¹ , a hydrogen partial pressure of 3 to 7 MPa, a hydrogen / oil ratio of 160 in the presence of a desulfurization catalyst containing cobalt-molybdenum or nickel-molybdenum. The hydrodesulfurization reaction is performed under a condition of ˜320 Nm ³ / kL.

  Moreover, this invention is obtained by mix | blending 95-50 volume% of light oil base materials manufactured by the method of the said description, and 5-50 volume% of kerosene base materials, 1 ring + 2 ring naphthenobenzene content ( The ionic strength%) is 9 to 14% and the induction period is 70 minutes or more.

  By the method of the present invention, a light oil base that uses a cracked light oil with low oxidation stability as a raw material, and that is appropriately mixed with a straight-run light oil raw material and hydrotreated to ensure oxidation stability that hardly generates sludge and deposits. The material can be manufactured. Moreover, by ensuring this good oxidation stability, there is an extraordinary effect that the oxidation stability can be improved without mixing many kerosene bases with good oxidation stability and without adding an antioxidant.

The present invention is described in detail below.
The method for producing a light oil base material of the present invention uses hydrogen as a raw material with a mixed oil consisting of 2 to 25% by volume of cracked light oil having a bicyclic aromatic content of 5 to 35% by volume and 75 to 98% by volume of straight-run gas oil. It is characterized by subjecting it to hydrodesulfurization treatment.

  Examples of cracked light oil include cracked light oil (LCO: Light Cycle Oil) produced by a fluid catalytic cracker, LCO hydrorefined oil, coal liquefied oil, heavy oil hydrocracked refined oil, coker light oil, and oil sand hydrogen. Examples include chemical and refined refined oils.

The bicyclic aromatic content of the cracked light oil in the present invention is required to be 35% by volume or less, preferably 34% by volume or less, more preferably 30% by volume or less, from the viewpoint of improving oxidation stability. is there. Further, from the viewpoint of maintaining lubricity, it is necessary to be 5% by volume or more, preferably 7% by volume or more, more preferably 10% by volume or more.
The term “bicyclic aromatic component” as used herein means a value measured by JPI-5S-49-97 “Petroleum products—hydrocarbon type test method—high performance liquid chromatograph method”.

The 10 vol% distillation temperature of the cracked light oil in the present invention is preferably 200 ° C to 250 ° C, more preferably 210 ° C to 250 ° C, and the 90 vol% distillation temperature is 335 ° C to 360 ° C. Is more preferable, and it is 335 ° C to 350 ° C.
The 10 vol% distillation temperature and 90 vol% distillation temperature mentioned here mean values measured by JIS K 2254 "Petroleum products-Distillation test method".

  The straight-run gas oil used as one component of the feedstock in the present invention is a light oil fraction distilled from an atmospheric distillation apparatus, and a 10% by volume distillation temperature is preferably 230 ° C to 285 ° C, more preferably. Is 250 ° C. to 285 ° C., more preferably 265 ° C. to 275 ° C., and the 90 vol% distillation temperature is preferably 340 ° C. to 370 ° C., more preferably 340 ° C. to 360 ° C.

  From the viewpoint of oxidation stability, the blended ratio of cracked gas oil and straight-run gas oil needs to be 25% by volume or less, preferably 22% by volume or less, more preferably 20% by volume or less. Further, from the viewpoint of preventing deterioration of fuel consumption, it is 2% by volume or more, preferably 4% by volume or more, more preferably 5% by volume or more.

Hydrodesulfurization reaction of a mixed oil composed of cracked gas oil and straight-run gas oil is carried out in the presence of a desulfurization catalyst containing cobalt-molybdenum or nickel-molybdenum at a reaction temperature of 310 to 395 ° C., preferably 320 to 380 ° C., LHSV 0.5 ˜2 hr ⁻¹ , preferably 0.8 to 1.8 hr ⁻¹ , hydrogen partial pressure 3 to 7 MPa, preferably 4 to 6 MPa, hydrogen / oil ratio 160 to 320 Nm ³ / kL, preferably 200 to 300 Nm ³ / kL. Done on condition.

  The form of the hydrodesulfurization reaction is not particularly limited, and any form such as a fixed bed, a moving bed, and a fluidized bed can be adopted.

  The hydrodesulfurization reaction is carried out so that the content of 1-ring + 2-ring naphthenobenzenes (ionic strength%) of the light oil base to be produced is 8.5 to 15.5%. By setting the content of 1-ring + 2-ring naphthenobenzenes (ionic strength%) to 8.5% or more, the oxidation stability improving effect can be enhanced. The content of 1-ring + 2-ring naphthenobenzenes (ionic strength%) is preferably 9.0% or more, and more preferably 9.5% or more. Also, if the content of 1-ring + 2-ring naphthenobenzenes is too large, the effect of improving oxidation stability is reduced, and the effect of addition of antioxidants is reduced, so that the content of 1-ring + 2-ring naphthenobenzenes (ion) The strength%) is preferably 15.5% or less, more preferably 15.0% or less, and still more preferably 14.0% or less.

  The light oil base material in the present invention is 2-25 vol% of cracked light oil whose bicyclic aromatic content is 5 to 35 vol% among the cracked light oil, and 75 of the light oil fraction distilled from the atmospheric distillation apparatus. The hydrodesulfurization treatment conditions are adjusted as appropriate so that the mixed oil consisting of ~ 98% by volume has the content of 1-ring + 2-ring naphthenobenzenes (ionic strength%), the induction period, and the cetane number within the ranges specified in this application. It can manufacture by processing. The hydrodesulfurization treatment conditions are adjusted by appropriately adjusting the reaction temperature, LHSV, hydrogen partial pressure, and hydrogen / oil ratio depending on the properties of cracked gas oil and straight-run gas oil. Since it is a category of desulfurization treatment conditions, a light oil base within the range specified in the present application can be easily obtained without requiring special trial and error.

  Here, how to obtain the content of 1-ring + 2-ring naphthenobenzenes (ionic strength%) will be described. First, the fuel composition is separated into an aromatic component and a saturated component by silica gel chromatography fractionation using diethyl ether and pentane. The weight of the aromatic component at this time is the Aroma value described later, and the weight of the saturated component is the Saturate value described later. Next, the GC-TOFMS method which combined the gas chromatograph and the mass spectrometry by FI ionization method was performed about the aromatic content and saturated content of the silica gel chromatographic fraction. The analysis conditions are shown below.

(GC condition)
Apparatus: 6890N manufactured by Agilent
Column: Agilent DB-1MS (30 m × 0.25 mmf × 0.25 μm)
Oven temperature: 50 ° C. (5 min) − (5 ° C./min) 280 ° C.
Injection volume: 0.5 μL
Injection method: split (split ratio = 1: 10)
Injection part temperature: 320 ° C
GC interface temperature: 300 ° C
Carrier gas: He 1.2 mL / min (constant)

(MS conditions)
Device: JEOL Ltd. JMS-T100GC
Counter electrode voltage: -10 kV
Ionization method: FI (field ionization)
Ion source temperature: room temperature Mass number measurement range: m / z 35-500

  In the mass spectrum obtained as a result of GC-TOFMS analysis, ionic strengths having mass numbers of 1-ring naphthenobenzenes to 6-ring naphthenobenzenes and alkylbenzenes for each carbon number, and The sum of the ionic strengths of the biphenyls and the aromatic masses of two or more rings is the total ionic strength of the aromatics. Tricyclic naphthenobenzenes are regarded as naphthalenes, and 4-ring naphthenobenzenes are regarded as biphenyls. In addition, 5-ring naphthenobenzenes to 6-ring naphthenobenzenes have ionic strengths that are respectively added because there are those whose mass numbers overlap with those of two or more ring aromatics. Obtain the percentage of the ionic strength by type for each carbon number obtained here from the percentage of the total ionic strength, and further correct the sum of the percentages to the value of Aroma. Ask for. By this method, the naphthenobenzene content (ionic strength%) can be determined.

The oxidation stability of a light oil base can be expressed by an induction period. If the induction period is short, sludge and deposits are likely to be generated. As a result, the fuel injection nozzle of the engine is likely to be clogged, resulting in a reduction in output and an adverse effect of corroding a metal material such as a fuel tank.
The induction period of the light oil base produced by the method of the present invention is 70 minutes or more, preferably 72 minutes or more, and more preferably 75 minutes or more.

  Here, a method for measuring the induction period will be described. First, a metal container containing a test fuel is sealed, and oxygen is sealed therein to a predetermined pressure. Thereafter, the sealed container is heated to a predetermined temperature, the predetermined pressure is maintained from the maximum pressure point to the point where the pressure drops by 10%, and the time from the start of heating to the 10% pressure drop point is measured, That time is the induction period.

(Measurement condition)
Apparatus: PetroXY apparatus (manufactured by Petrotest)
Oxygen filling pressure: 700 kPa (gauge pressure)
Test temperature: 140 ° C
Test fuel volume: 5mL

The cetane number of the light oil base produced by the method of the present invention is 51.0 or more, more preferably 52.0 or more, and further preferably 53.0 or more from the viewpoint of engine startability. .
The cetane number here means a value measured and calculated according to JIS K 2280 “Petroleum products—fuel oil—octane number and cetane number test method and cetane index calculation method”.

The monocyclic aromatic content of the light oil base produced by the method of the present invention is preferably 15.0 to 24.5% by volume, more preferably 17.0 to 24.5% by volume. The bicyclic aromatic content is preferably 5.0% by volume or less, and more preferably 3.0% by volume or less. Further, the aromatic content of 3 or more rings is preferably 1.5% by volume or less, and more preferably 1.0% by volume or less.
The 1-ring aromatic content, 2-ring aromatic content and 3 or more ring aromatic content mentioned here are measured by JPI-5S-49-97 "Petroleum products-Hydrocarbon type test method-High performance liquid chromatograph method". Value.

  The light oil composition of the present invention can be obtained by mixing 5 to 50% by volume of kerosene base material with 95 to 50% by volume of light oil base material produced by the method described above. Thereby, it is possible to obtain a light oil composition with improved oxidation stability without mixing a large amount of kerosene base material with good oxidation stability.

  As the kerosene base material, a petroleum-based kerosene base material can be used. Examples of the petroleum-based kerosene base include straight-run kerosene obtained from a crude oil atmospheric distillation apparatus; depressurized kerosene obtained by applying a straight-run heavy oil and residual oil obtained from an atmospheric distillation apparatus to a vacuum distillation apparatus; Hydrogenation refined kerosene obtained by hydrorefining kerosene or reduced pressure kerosene; Hydrogenation obtained by hydrodesulfurization of straight-run kerosene or reduced pressure kerosene in one or more stages under conditions severer than normal hydrorefining Desulfurized kerosene; hydrocracked kerosene obtained by hydrocracking the above-mentioned various kerosene substrates.

  Kerosene bases with generally good oxidation stability are hydrodesulfurized kerosene bases obtained by hydrodesulfurizing only petroleum kerosene raw materials, or hydrocracked kerosene bases obtained by hydrocracking at high temperature and high pressure. Since it is a material, the mixing ratio of the kerosene base material is preferably 50% by volume or less, more preferably 45% by volume or less, and still more preferably 40% by volume or less, due to high production costs and jet fuel use. . In order to obtain the effect of improving oxidation stability, the content is preferably 5% by volume or more, more preferably 8% by volume or more, and still more preferably 10% by volume or more.

  The light oil composition of the present invention may contain a low temperature fluidity improver as necessary. The type of the low-temperature fluidity improver is not particularly limited. For example, ethylene-unsaturated ester copolymer represented by ethylene-vinyl acetate copolymer, alkenyl succinic acid amide, dibehenic acid ester of polyethylene glycol Linear compounds such as phthalic acid, ethylenediaminetetraacetic acid, nitriloacetic acid and the like, or polar nitrogen compounds consisting of reaction products of hydrocarbyl-substituted amines, alkyl fumarate or alkyl itaconate-unsaturated esters One kind or two or more kinds of low-temperature fluidity improvers such as a comb polymer made of a copolymer can be used. Among these, from the viewpoint of versatility, an ethylene-vinyl acetate copolymer additive can be preferably used. When the low temperature fluidity improver is added, the addition amount is preferably 50 to 500 mg / L, and particularly preferably 50 to 300 mg / L. In addition, since a commercial product referred to as a low temperature fluidity improver may be diluted with an appropriate solvent for an active ingredient that contributes to low temperature fluidity, such a commercial product may be used as the fuel oil composition of the present invention. In the case of adding to the above, the above-mentioned addition amount means the addition amount as an active ingredient.

  The light oil composition of the present invention may contain a lubricity improver from the viewpoint of ensuring lubricity in the injection pump. The type of the lubricity improver is not particularly limited, but one or more of the lubricity improvers such as ester, carboxylic acid, alcohol, phenol, and amine can be used. . Among these, from the viewpoint of versatility, it is preferable to use an ester-based or carboxylic acid-based lubricity improver. Furthermore, an ester-based lubricity improver is preferable from the viewpoint that the effect of addition with respect to the concentration of addition hardly reaches saturation and the WS1.4 value of HFRR can be further reduced, and the initial response of the effect of addition with respect to the concentration of addition is high. Carboxylic acid type lubricity improvers are preferred from the viewpoint that the amount of addition of can be reduced.

  Examples of the ester-based lubricity improver include glycerin carboxylic acid ester and the like. The carboxylic acid constituting the carboxylic acid ester may be one type or two or more types, and specific examples thereof include linoleic acid, oleic acid, salicylic acid, palmitic acid, myristic acid, hexadecenoic acid and the like. . Examples of the carboxylic acid-based lubricity improver include linoleic acid, oleic acid, salicylic acid, palmitic acid, myristic acid, hexadecenoic acid, and the like, and one or more of these can be used arbitrarily. is there. In addition, when a low temperature fluidity improver has a lubricity improvement effect, the low temperature fluidity improver and the lubricity improver can be combined to improve lubricity.

  When the lubricity improver is added, the addition amount is preferably 25 to 500 mg / L, more preferably 25 to 300 mg / L, and still more preferably 25 to 200 mg / L. Thus, the WS1.4 value of HFRR is preferably 500 μm or less, more preferably 460 μm or less, still more preferably 420 μm or less, and most preferably 400 μm or less. Commercially available products called lubricity improvers are usually obtained in a state where the active ingredients that contribute to lubricity are diluted with a suitable solvent. In the case where such a commercial product is added to the fuel oil composition of the present invention, the above addition amount means the addition amount as an active ingredient.

  The 1-ring + 2-ring naphthenobenzene content (ionic strength%) according to the light oil composition of the present invention is preferably 9.0% or more, more preferably 9. 5% or more, more preferably 10.0% or more. Further, if the content of 1-ring + 2-ring naphthenobenzenes is too large, the effect of improving oxidation stability is reduced, and the effect of adding an antioxidant is reduced, so that it is preferably 14.0% or less. Preferably it is 13.5% or less, More preferably, it is 13.0% or less.

  The oxidation stability according to the light oil composition of the present invention can be expressed by an induction period. If the induction period is short, sludge and deposits are likely to be generated. As a result, the fuel injection nozzle of the engine is likely to be clogged, resulting in a reduction in output and an adverse effect of corroding a metal material such as a fuel tank. The induction period is preferably 70 minutes or longer, more preferably 72 minutes or longer, and even more preferably 75 minutes or longer.

  Hereinafter, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these.

(Examples 1-5 and Comparative Examples 1-2)
A light oil base material was prepared by mixing cracked light oil (LCO) obtained from a fluid catalytic cracker and straight-run gas oil, which is a distillate from an atmospheric distillation apparatus, at an arbitrary ratio, and treating with hydrodesulfurization equipment. . These raw material properties are shown in Tables 1 and 2, and the light oil base material is shown in Table 3.

(Preparation of light oil composition)
The light oil base material of Example 5 and Comparative Example 1 and the kerosene base material described in Table 4 were blended to prepare a light oil composition having the composition and properties shown in Table 5.

  From this result, it is possible to produce a light oil base material that ensures oxidation stability, which is difficult to generate sludge and deposits, even if a cracked light oil with low oxidation stability is appropriately mixed as a raw material and hydrotreated. As a result of this good oxidation stability, it was found that the oxidation stability can be improved without mixing a large amount of kerosene base material with good oxidation stability and without adding an antioxidant. .

  By the method of the present invention, a light oil composition ensuring oxidation stability can be obtained, which is extremely useful industrially.

Claims (4)

  1-ring + 2-ring naphthenobenzene is obtained by hydrodesulfurizing a mixed oil composed of 2 to 25 volume% of cracked gas oil having a bicyclic aromatic content of 5 to 35 volume% and 75 to 98 volume% of straight-run gas oil. A method for producing a light oil base material, characterized in that a gas oil base material having an organic content (ionic strength%) of 8.5 to 15.5%, an induction period of 70 minutes or more, and a cetane number of 51 or more is obtained.   The 10 vol% distillation temperature of cracked gas oil is 200 ° C to 250 ° C, the 90 vol% distillation temperature is 335 ° C to 360 ° C, the cetane index is 29 to 35, and the 10 vol% distillation temperature of straight gas oil is 230. The method for producing a light oil base material according to claim 1, wherein the distillation temperature is from 340 ° C to 285 ° C and a 90% by volume distillation temperature is from 340 ° C to 370 ° C. In the presence of a desulfurization catalyst containing cobalt-molybdenum or nickel-molybdenum, a reaction temperature of 310 ° C. to 395 ° C., LHSV 0.5 to 2 hr ⁻¹ , hydrogen partial pressure 3 to 7 MPa, hydrogen / oil ratio 160 to 320 Nm ³ / kL 3. The method for producing a light oil base material according to claim 1, wherein the hydrodesulfurization reaction is performed under conditions.   1 ring + 2 ring naphthenobenzenes content obtained by mix | blending 95-50 volume% of light oil base materials manufactured with the method in any one of Claims 1-3 and 5-50 volume% of kerosene base materials A light oil composition having an amount (ionic strength%) of 9 to 14% and an induction period of 70 minutes or more.