JP4371925B2 - Unleaded gasoline composition and method for producing the same - Google Patents

Description

  The present invention relates to an unleaded gasoline composition with reduced environmental impact and a method for producing the same. In particular, the present invention relates to an unleaded gasoline composition that secures sufficient operating characteristics while reducing the influence on the environment by reducing the sulfur content and ensuring a high octane number, and a method for producing the same.

  In recent years, the demand for high-performance gasoline having high driving performance has increased with the improvement in performance of automobiles. On the other hand, environmental pollution due to automobile fuel and its combustion exhaust gas has become a social problem. Therefore, an automobile fuel that maintains high driving performance and has a low environmental impact is desired. In particular, further reduction of sulfur content is desired from the viewpoint of exhaust gas purification and fuel efficiency improvement.

  JIS K 2202 stipulates No. 1 automobile gasoline with a research octane number (RON) of 96.0 or more and No. 2 automobile gasoline with 89.0 or more. The former is a high-performance premium gasoline and the latter is regular. Commercially available as gasoline. Conventionally, premium gasoline has a catalytic reforming gasoline base, a base with more than 100 RON such as methyl t-butyl ether (MTBE), 93 or more RON such as alkylate gasoline base, catalytic cracking gasoline base It is manufactured by blending various types of base materials, mainly on base materials with

  The catalytic cracking gasoline base produced by catalytic cracking of heavy petroleum fractions has the advantage that it can be produced economically compared to other premium gasoline bases, while containing a high sulfur content. As a result, most of the sulfur content in the premium gasoline produced as described above was derived from the catalytic cracked gasoline base material.

  The sulfur content of the catalytic cracking gasoline base can be easily reduced by a known technique of hydrotreating in the presence of high-pressure hydrogen and a catalyst. However, in that case, a large amount of the catalytic cracking gasoline base material is contained, and the olefin component having a high RON is hydrogenated to lower the RON of the base material. There was a problem that it could not be obtained.

  An environment-friendly gasoline having a sulfur content as low as 1 mass ppm or less and sufficient practical performance, and a method for producing the same have not yet been established. An object of the present invention is to provide an unleaded gasoline composition and a method for producing the same, in which the sulfur content is reduced and sufficient operating characteristics are ensured under such circumstances.

  As a result of diligent research to solve the above-mentioned problems, the present inventors have used catalytic cracked oil having a low sulfur content, and by using only a specific fraction as a base material, while maintaining a high RON. The present inventors have arrived at an unleaded gasoline composition that reduces sulfur content, ensures sufficient operating characteristics and excellent environmental conservation, and a method for producing the same.

That is, the method for producing an unleaded gasoline composition having a sulfur content of 1 mass ppm or less and a research octane number of 93.0 or more according to the present invention,
(1) Light naphtha fraction in which catalytic cracking oil is fractionated and the thiophene content is 2 mass ppm or less as the sulfur content, the 5% distillation temperature is 25 to 43 ° C., and the 95% distillation temperature is 55 to 80 ° C. A first step of obtaining
(2) A second step of mixing the light naphtha fraction obtained in the first step and another gasoline base material having a sulfur content of 0.5 mass ppm or less is included.

  Preferably, 10 to 45% by volume of light naphtha fraction and 90 to 55% by volume of other gasoline base are mixed in the second step. Moreover, it is preferable to perform the process which reduces the thiols contained in a light naphtha fraction in the middle of a 1st process or after a 1st process, and uses a light naphtha fraction for a 2nd process.

  The lead-free gasoline composition according to the present invention has a research octane number of 93.0 or more, a 50 volume% distillation temperature of 105 ° C. or less, an olefin content of 10 volume% or more, and a total sulfur content of 1 mass ppm or less. . Preferably, the proportion of thiophene in the total sulfur content is 40% by mass or more as the sulfur content, and / or the olefin content in the boiling range of 25 to 80 ° C. in the total olefin content is 90% by volume or more.

  The present invention fractionates a light naphtha fraction having a thiophene content of 2 ppm by mass or less, a 5% distillation temperature of 25-43 ° C., and a 95% distillation temperature of 55-80 ° C. And a second step of mixing the light naphtha fraction obtained in the first step with another gasoline base material having a sulfur content of 0.5 ppm or less, and having a sulfur content of 1 ppm by mass The following is a method for producing an unleaded gasoline composition having a research octane number of 93.0 or more. Therefore, the present invention has an exceptional effect that it is possible to provide an environmentally friendly gasoline having an extremely low sulfur content of 1 mass ppm or less and ensuring sufficient RON by an easy operation.

[First step]
In the first step of the method for producing an unleaded gasoline composition of the present invention, the catalytically cracked oil is fractionally distilled to give a 5% by volume distillation temperature of 25 to 43 ° C, preferably 30 to 40 ° C, and 95 volumes. A light naphtha fraction having a% distillation temperature of 55 to 80 ° C, preferably 60 to 70 ° C is obtained. When the 5% by volume distillation temperature is less than 25 ° C, the vapor pressure of the unleaded gasoline composition increases. When the 95% by volume distillation temperature exceeds 75.0 ° C, particularly 80 ° C, the sulfur content of the light naphtha fraction increases or the RON of the gasoline base material decreases. If the 5% by volume distillation temperature exceeds 43 ° C. or the 95% by volume distillation temperature is less than 55 ° C., it is difficult to adjust the distillation properties of the unleaded gasoline composition, or it is obtained in the first step. The yield of the light naphtha fraction is reduced and the cost of the unleaded gasoline composition is increased. The fractionation of catalytic cracking oil may be performed in one stage or in multiple stages. A method of fractionating a product obtained by catalytic cracking to obtain a naphtha fraction and further fractionating the obtained naphtha fraction is a light naphtha fraction that is fractionated in multiple stages and used in the second step. Is one of the preferred methods of obtaining

  As the catalytic cracking oil to be used in the first step, it is preferable to use one having a total sulfur content in a fraction having a distillation temperature of 40 ° C to 170 ° C of 15 mass ppm or less. This fraction preferably contains 0.1 to 2 mass ppm, more preferably 0.3 to 2 mass ppm of thiophene as a sulfur component in the sulfur compound. Since thiophene is one of the sulfur compounds most likely to remain in catalytic cracking, it is not preferable to reduce the thiophene in the catalytic cracking oil to less than 0.1 ppm by mass because the cost of the unleaded gasoline composition increases. On the other hand, if the thiophene content in the distillate whose catalytic cracking oil has a distillation temperature of 40 ° C. to 170 ° C. exceeds 2 mass ppm, the total sulfur content of the unleaded gasoline composition is reduced to 1 mass ppm or less in the second step. Is not preferable.

  Moreover, it is preferable that the light naphtha fraction obtained at a 1st process contains 0.1-2 mass ppm of thiophene as a sulfur content. When thiophene exceeding 2 ppm by mass is contained as the sulfur content, the amount of light naphtha fraction that can be blended in the unleaded gasoline composition in the second step is restricted, which is not preferable. It is not preferable that the light naphtha fraction obtained in the first step contains only thiophene having a sulfur content of less than 0.1 mass ppm because the yield of the light naphtha fraction is reduced. It is preferable that 2-methylthiophene and 3-methylthiophene contained in the light naphtha fraction obtained in the first step have a total sulfur content of 0.2 mass ppm or less. Similarly to thiophene, 2-methylthiophene and 3-methylthiophene are sulfur compounds that are likely to remain in catalytic cracking, and are sulfur compounds that are likely to be mixed into the light naphtha fraction obtained in the first step. Therefore, in the first step, it is preferable to reduce 2-methylthiophene and 3-methylthiophene contained in the light naphtha fraction, and it is more preferable that the total sulfur content is 0.1 mass ppm or less. For this purpose, the 95% distillation temperature of the light naphtha fraction is preferably 75 ° C., particularly 70 ° C. or less. The light naphtha fraction can further reduce sulfur compounds by adsorption treatment or the like, but according to the present invention, in the first step, without undergoing sulfur compound reduction treatment other than the treatment for reducing thiols described below. The resulting light naphtha fraction can be used in the second step.

[Process for producing catalytic cracking oil]
The process for producing the catalytic cracking oil used in the first step particularly limits the catalytic cracking apparatus, the feed oil, the operating conditions, and the catalyst to be used, as long as a catalytic cracking oil having a low content of sulfur compounds such as thiophene is obtained. Any known one can be adopted. The catalytic cracking unit uses a catalyst such as amorphous silica alumina, zeolite, etc., in addition to petroleum fractions from light oil to vacuum gas oil, while being obtained from heavy oil indirect desulfurization unit, it can be obtained directly from degassing oil or heavy oil direct desulfurization unit. This is a device that obtains a high octane gasoline base material by catalytic cracking of degassed oil, atmospheric residue oil and the like. For example, UOP catalytic cracking method, flexi cracking method, ultra-orthoflow method, texaco fluid catalytic cracking method such as fluid catalytic cracking method, RCC method, HOC method, etc. There are oil fluid catalytic cracking methods. Also, 21st JPI Petroleum Refining Conference “Recent Progress in Petroleum Process Technology”, p.113-158 (2002), Sulfur, 268, 35, (2000), “Production of Low Sulfur Gasoline and Diesel Fuels: Tier 2 and Beyond” , Petroleum Refining Technology Seminar, p.4-24 (August 2001), JP-A-6-277519, a catalytic cracking catalyst having a high desulfurization effect or an additive having a desulfurization effect is used as a catalytic cracking catalyst. It is preferable to use it by adding to it in order to obtain the catalytic cracked oil used in the first step of the present invention.

  In order to reduce the sulfur content such as thiophene in the light naphtha fraction, hydrorefining is performed so that the sulfur content of the feedstock oil of the catalytic cracker is 2000 mass ppm or less, further 1000 mass ppm or less, especially 700 mass ppm or less. It is preferable to use a petroleum fraction reduced by such means. As this petroleum fraction, gas oil to vacuum gas oil is preferable. A vacuum gas oil fraction is also preferably used from gas oil obtained by subjecting vacuum distillation residue or atmospheric distillation residue to thermal decomposition or the like.

[Treatment to reduce thiols]
Since the thiols contained in the catalytic cracking oil cause causative substances in the unleaded gasoline composition, it is preferable to perform a treatment for reducing the thiols in the unleaded gasoline composition. The treatment may be performed on the light naphtha fraction obtained in the first step, or may be performed between fractionation treatments when fractional distillation is performed in multiple stages. Good. Performing the treatment for reducing the thiols with respect to the total amount of the catalytically cracked oil to be subjected to the first step is not preferable because the apparatus for the treatment becomes large. Specifically, the total content of thiols in the light naphtha fraction is preferably 2 ppm by mass or less, more preferably 1 ppm by mass or less in terms of sulfur content. In addition, as a treatment for reducing thiols, when applying a method that does not substantially reduce the sulfur concentration by converting thiols into a higher boiling sulfur compound, fractional distillation is performed in multiple stages. It is preferable to perform a treatment for reducing thiols between the treatment and the fractional distillation treatment. For example, a naphtha fraction is obtained by fractionation of catalytic cracked oil, and the naphtha fraction is subjected to a treatment for reducing thiols by applying the Marrox method to convert the thiols into disulfides, followed by fractionation. And a method for obtaining a light naphtha fraction. When the fractionation and the treatment for reducing thiols are combined in this way, disulfides having a high boiling point can be removed from the light naphtha fraction, so that the sulfur content of the light naphtha fraction can be reduced.

  Conventionally, in petroleum refining, sweetening is performed to treat the thiols to make the product non-brominated, but a known method for converting thiols to disulfides by an oxidation method or an oxidation extraction method is the present invention. Can be applied as a method for reducing thiols. Specifically, the Marlox method, the doctor method, and the like disclosed in known documents (Sangyo Tosho Co., Ltd., Petroleum Refining Technology Handbook 3rd Edition, 1981) are preferably used.

  In the present invention, as a method for reducing thiols, a method of reacting a sulfur compound contained in a naphtha fraction with olefins is also preferably used. Specifically, the method of reacting thiols and olefins disclosed in JP-A-2001-55584 and known documents (“Production of Low Sulfur Gasoline and Diesel Fuels: Tier 2 and Beyond”, Petroleum Refining Technology Seminar August 2001, 11-18) is a method of reacting thiols and thiophenes with olefins.

[Other gasoline base materials used in the second step]
In the second step, as other gasoline base materials mixed with the light naphtha fraction obtained in the first step, catalytic reforming gasoline base material, alkylate gasoline base material, straight-run naphtha was desulfurized. Base materials and gasoline base materials such as oxygen-containing gasoline base materials such as methyl t-butyl ether (MTBE), ethyl t-butyl ether (ETBE), t-amyl ethyl ether (TAEE), ethanol, and methanol can be used. The other gasoline base material mixed in the second step preferably has a sulfur content of 0.5 mass ppm or less, and more preferably 0.1 mass ppm or less. If the sulfur content of the other gasoline base exceeds 0.5 ppm by mass, the amount of the light naphtha fraction obtained in the first step in the unleaded gasoline composition is restricted, which is not preferable.

  Preferred blending amounts are 10 to 45% by volume of light naphtha fraction, particularly 25 to 40% by volume, 25 to 50% by volume of catalytic reformed gasoline base, particularly 30 to 45% by volume, and 10% alkylate gasoline base. -40% by volume, in particular 15-30% by volume.

[Other ingredients]
Furthermore, the gasoline composition of the present invention may contain one or more fuel oil additives known in the art as needed. Although these compounding quantities can be selected suitably, it is preferable to maintain the total compounding quantity of an additive to 0.1 weight% or less normally. Examples of fuel oil additives that can be used in the gasoline of the present invention include phenolic, amine-based antioxidants, Schiff-type compounds, metal deactivators such as thioamide-type compounds, and organic phosphorus-based surfaces. Anti-ignition agent, detergent / dispersant such as succinimide, polyalkylamine, polyetheramine, anti-icing agent such as polyhydric alcohol or its ether, alkali metal salt or alkaline earth metal salt of organic acid, sulfuric acid of higher alcohol Examples include an auxiliary combustor such as an ester, an anionic surfactant, a cationic surfactant, an antistatic agent such as an amphoteric surfactant, and a colorant such as an azo dye.

[Unleaded gasoline composition]
The unleaded gasoline composition of the present invention has a research octane number of 93.0 or more, preferably 98 to 102, a 50% by volume distillation temperature of 105 ° C. or less, preferably 80 to 100 ° C., and an olefin content of 10 The volume% or more, preferably 10 to 20 volume%, and the total sulfur content is 1 mass ppm or less. Furthermore, the ratio of thiophene in the total sulfur content is preferably 40 to 100% by mass, particularly 50 to 80% by mass as the sulfur content. It is preferable to contain 0.1 to 1.0 mass ppm of thiophene in the unleaded gasoline composition as a sulfur content. Since thiophene is one of the sulfur compounds that are most likely to remain in the light naphtha fraction used as the base material, the thiophene having a sulfur content of less than 0.1 ppm by mass increases the cost of the unleaded gasoline composition of the present invention. It is not preferable. Moreover, it is preferable that 2-methylthiophene and 3-methylthiophene are 0.2 mass ppm or less, particularly 0.1 mass or less as the total sulfur content.
Furthermore, it is preferable that the unleaded gasoline composition has an olefin having a boiling point range of 25 to 80 ° C. in the total olefin content of 90% by volume or more because RON of the low boiling point fraction increases.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

[Preparation of light naphtha fraction C used in Examples]
A catalytic cracked oil obtained by fluid catalytic cracking using a hydrorefined gas oil fraction (sulfur content: 2.6 mass%) of Middle Eastern crude oil as the main feed oil (sulfur content: 700 mass ppm) The naphtha fraction A was obtained by fractional distillation. Naphtha fraction A was oxidized in the presence of alkali to obtain naphtha fraction B. Naphtha fraction B was fractionated, and the light and heavy components were removed to obtain light naphtha fraction C. The properties of naphtha fraction A, naphtha fraction B, and light naphtha fraction C are as shown in Table 1.
The density was measured according to JIS K 2249, and the distillation property was measured according to JIS K 2254. The sulfur content was measured by the microcoulometric titration method of JIS K2541. The content of sulfur compounds (in terms of sulfur) was measured by gas chromatography using a Shimadzu gas chromatograph equipped with an ANTEK sulfur chemiluminescence detector that selectively detects and quantifies sulfur compounds by chemiluminescence. . The hydrocarbon component composition and RON were measured by gas chromatography using a PIONA apparatus manufactured by Hured Packard.
Light thiols contained in the naphtha fraction A were converted to disulfides by oxidative extraction treatment. The light naphtha fraction C contained 1.3 mass ppm of total sulfur and 0.8 mass ppm of thiophene, but did not contain 2-methylthiophene and 3-methylthiophene. Further, the olefin content contained in the light naphtha fraction C had a boiling point of 25 to 80 ° C.

[Preparation of light naphtha fraction F used in comparative examples]
Instead of using naphtha fraction A, fluidized contact is made by using hydrorefined processing of a vacuum gas oil fraction (sulfur content: 2.6 mass%) of Middle Eastern crude oil as the main feed oil (sulfur content: 1800 massppm). The catalytic cracked oil obtained by cracking was fractionated to obtain naphtha fraction D. A naphtha fraction E was obtained by oxidation extraction treatment in the same manner as described in the preparation of the light naphtha fraction C from the naphtha fraction A except that the naphtha fraction D was used. Further, the naphtha fraction E was fractionated, and the light and heavy components were removed to obtain a light naphtha fraction F. Properties of naphtha fraction D, naphtha fraction E, and light naphtha fraction F are as shown in Table 2.

〔実施例１〕

[Example 1]

Desulfurized naphtha G, catalytic reforming medium oil H, catalytic reforming heavy oil I, and alkylate gasoline J were used as other gasoline base materials obtained by known techniques other than catalytic cracking. Their properties are as shown in Table 3. Note that the catalytically reformed intermediate oil H is obtained by distilling and separating a toluene-rich fraction from catalytically reformed gasoline. The catalytically modified heavy oil I is obtained by distilling and separating aromatics having 9 or more carbon atoms and less than 11 from catalytically modified gasoline.
The desulfurized naphtha G, the catalytically modified medium oil H, the catalytically modified heavy oil I, the alkylate gasoline J, and the light naphtha fraction C are blended as shown in Table 4, and the additive is colored. 2 mg / L of an additive (CL-53 manufactured by Silado Chemical Co., Ltd.), 20 mg / L of an antioxidant (Sumitizer 4ML manufactured by Sumitomo Chemical Co., Ltd.), and 100 mg / L of a cleaning dispersant (Keropur AP-95 manufactured by BISF) Unleaded gasoline compositions K, M and N were prepared. The properties are as shown in Table 5. Moreover, the olefin content of the boiling range 25-25 degreeC which occupies for all the olefin content of the unleaded gasoline composition K, M, and N is 99.9 volume% or more.

〔比較例１〕

[Comparative Example 1]

  An unleaded gasoline composition L of Comparative Example 1 was prepared in the same manner as in Example 1 except that the light naphtha fraction F was used instead of the light naphtha fraction C. The properties are shown in Table 5 together with the unleaded gasoline composition K of the present invention.

表５から、本発明によって提供される無鉛ガソリン組成物Ｋ、Ｍ、Ｎは、比較例の無鉛ガソリン組成物Ｌと比べてＲＯＮをはじめ他の性状をほとんど変えることなく、硫黄分を１質量ppm以下に低減できることが明らかである。

From Table 5, the unleaded gasoline compositions K, M, and N provided by the present invention have a sulfur content of 1 ppm by mass with almost no change in other properties such as RON as compared with the unleaded gasoline composition L of the comparative example. It is clear that the following can be reduced.

It was possible to find a gasoline with a reduced sulfur content and a sufficient RON and a method for producing the same. As a result, it is possible to provide environmentally friendly gasoline that ensures sufficient practical performance.

Claims (4)

The catalytically cracked oil is treated to reduce the thiols contained in the fraction and light naphtha fraction, so that the thiophene content is 2 mass ppm or less as the sulfur content, and the thiols content is 1 mass ppm or less in total as the sulfur content. The first step of obtaining a light naphtha fraction having a% distillation temperature of 25 to 43 ° C and a 95% distillation temperature of 55 to 80 ° C, and the light naphtha fraction 25 to 45 obtained in the first step and a second step of mixing the volume percent sulfur 0.5ppm following other gasoline components 75-55 volume%, sulfur content of 1 mass ppm or less, and research octane number is 93.0 or more A method for producing an unleaded gasoline composition. An unleaded gasoline produced by the method for producing an unleaded gasoline composition according to claim 1 , having a research octane number of 93.0 or more, a 50% by volume distillation temperature of 105 ° C or less, and an olefin content of 10 volumes. %, And an unleaded gasoline composition having a total sulfur content of 1 mass ppm or less. The unleaded gasoline composition according to claim 2 , wherein the proportion of thiophene in the total sulfur content is 40 mass% or more as the sulfur content. The unleaded gasoline composition according to claim 2 or 3 , wherein the olefin content in the boiling range of 25 to 80 ° C in the total olefin content is 90% by volume or more.