JP2006104224A - Unleaded gasoline composition and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an unleaded gasoline composition wherein sulfur content and diene number are reduced and a sufficient driving performance is ensured, and its production method. <P>SOLUTION: The unleaded gasoline composition has a total sulfur content of ≤10 mass ppm, an olefin content of 5-30 vol.%, a diene number of ≤0.3 g/100 g and a research octane number of ≥89, wherein the proportion of CH<SB>2</SB>carbons having carbon-carbon double bonds (=CH<SB>2</SB>carbons) to all carbons is <1%. A cracked gasoline base which is capable of retaining a high RON and reducing the diene content in a cracked gasoline fraction is produced by contacting the cracked gasoline fraction with a catalyst containing at least one metal chosen from group 8 elements in the periodic table in the presence of hydrogen to reduce the diene number and to reduce the proportion of =CH<SB>2</SB>carbons to all carbons more significantly compared to the reduction of the proportion of unsaturated carbons to all carbons. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an unleaded gasoline composition and a method for producing the same, and in particular, by controlling the chemical structure and composition of the olefin compound contained in the unleaded gasoline composition, while ensuring sufficient operation performance, the sulfur content and the diene. The present invention relates to an unleaded gasoline composition having a reduced value and a method for producing the same.

  Cracked gasoline fractions produced by cracking heavy petroleum fractions, such as catalytic cracking and thermal cracking, can be produced more economically than other gasoline bases and have a relatively high research octane number (RON) Due to the advantage of being rich in olefins, it is used as a base material for unleaded gasoline compositions. However, since the cracked gasoline fraction contains a large amount of sulfur, if a gasoline composition containing a large amount of cracked gasoline fraction is used as a fuel, it can effectively act as a NOx storage type gasoline automobile exhaust gas purification catalyst. There was a problem that I could not. Moreover, since the cracked gasoline fraction contains a large amount of dienes, the cracked gasoline fraction is susceptible to polymerization and oxidation reactions, which has caused the deterioration of the stability of the gasoline composition.

  Reduction of the sulfur content and dienes contained in the cracked gasoline fraction can be easily achieved by a known technique in which the cracked gasoline fraction is hydrotreated in the presence of high-pressure hydrogen and a catalyst. However, in that case, the hydrotreated oil obtained in such a manner is contained in the cracked gasoline fraction, and the olefin content having a relatively high RON is hydrogenated to lower the RON of the base material. In the unleaded gasoline composition which mix | blended as a base material, there existed a problem that sufficient driving | operation performance was not obtained.

For example, (1) a step of subjecting a catalytically cracked gasoline having a sulfur content of 200 mass ppm or less to sweet distillation and then distilling it into a light fraction having a sulfur content of 20 mass ppm or less and a heavy fraction containing the remaining sulfur content. (2) A hydrodesulfurization step for reducing the research octane number to 3 or less and a sulfur content to 20 mass ppm or less, and (3) a light fraction obtained in the step (1). , The heavy fraction obtained in the step (2), and the gasoline base material other than catalytic cracking gasoline and having a sulfur content of 10 mass ppm or less, and the sulfur content is 8 mass ppm There has been proposed a method for producing low-sulfur gasoline, which comprises a process for producing the following product gasoline (see Patent Document 1). However, this method cannot ensure practical performance by maintaining sufficient RON by reducing dienes and changing the structure of olefins.

On the other hand, as a method for reducing dienes, at least one step (step a) for selectively hydrogenating diolefins present in the starting gasoline, at least for converting light sulfur-containing compounds present in the gasolines. One step (step b), at least one step (step c) for fractionating the gasoline obtained in step a or b into at least two fractions, a light fraction and a heavy fraction, step c Process for producing gasoline with a low sulfur content comprising at least each of the steps (step d) of desulfurizing at least a part of the heavy fraction obtained from the fractionation in Japan, and low sulfur equivalent thereto A method for producing gasoline has been proposed (see Patent Documents 2 to 6). Although these methods can reduce gasoline sulfur and reduce dienes, it is impossible to change the olefin structure to maintain sufficient RON to ensure practical performance.
JP 2003-183676 A JP-T-2004-523628 JP-T-2004-523629 JP 2000-161069 A JP 2001-55584 A JP 2001-279263 A

  As described above, an unleaded gasoline composition that reduces the sulfur content and dienes and maintains sufficient RON to ensure practical performance and a method for producing the same have not yet been established. An object of this invention is to provide the lead-free gasoline composition which reduced sulfur content and the diene value, and its manufacturing method, ensuring sufficient driving | operation performance in such a condition.

  As a result of diligent research to solve the above-mentioned problems, the present inventors contact a cracked gasoline fraction with a catalyst containing at least one metal selected from Group 8 elements of the periodic table in the presence of hydrogen. In addition to reducing the diene content, an olefin compound having a carbon-carbon double bond at the end of the carbon chain having a relatively low RON (terminal olefin compound) can be introduced into the carbon chain having a relatively high RON. It can be converted into an olefin compound having an internal bond (internal olefin compound), and it can be found that the diene content can be efficiently reduced without significantly reducing RON, and the substrate thus obtained is used. Has found that an unleaded gasoline composition having sufficient operating characteristics can be obtained, and the unleaded gasoline composition of the present invention and its production It was conceived with the law.

That is, the lead-free gasoline composition according to the present invention has a total sulfur content of 10 ppm by mass or less, an olefin content of 5 to 30% by volume, a diene value of 0.3 g / 100 g or less, and CH ₂ carbon having a carbon-carbon double bond. The proportion of the (= CH ₂ carbon) number in the total carbon number is less than 1%, and the research octane number is 89 or more. The CH ₂ carbon having a carbon-carbon double bond as used in the present invention refers to a carbon that is bonded to two atoms of hydrogen and has a carbon-carbon double bond, and hereinafter referred to as “═CH ₂ carbon”. Sometimes abbreviated.

  The unleaded gasoline composition according to the present invention preferably has a RON of 92 or more.

In the method for producing an unleaded gasoline composition of the present invention, the whole or part of the cracked gasoline fraction is brought into contact with a catalyst containing at least one metal selected from Group 8 elements in the periodic table in the presence of hydrogen. And the step of reducing the diene number and reducing the proportion of CH ₂ carbon in the total number of carbons more than the decrease in the proportion of the unsaturated carbon number in the total number of carbons (step A). 30% by volume or more of a gasoline base material (cracked gasoline base material) derived from a cracked gasoline fraction containing the treated oil obtained, and the lead-free gasoline composition produced has a total sulfur content of 10 Mass ppm or less, olefin content is 5 to 30% by volume, diene value is 0.3 g / 100 g or less, and the proportion of CH ₂ carbon in the total number of carbon atoms is less than 1%, and the research octane number is 89 or more. Is.

  The method for producing an unleaded gasoline composition of the present invention preferably includes a step of fractionating a cracked gasoline fraction (Step B), and the heavy cracked gasoline fraction obtained in Step B is molybdenum in the presence of hydrogen. Or the desulfurization process (process C) which makes it contact with the catalyst containing tungsten and reduces the total sulfur content of a heavy catalytic cracking gasoline fraction to 20 mass ppm or less is included. Moreover, Preferably, the process (process D) which enlarges the molecular weight of the sulfur compound contained in a cracked gasoline fraction is included. More preferably, the research method octane number of the unleaded gasoline composition is 92 or more.

Dienes are inevitably contained in various cracked gasoline fractions such as catalytic cracked gasoline fraction and pyrolyzed gasoline fraction. When a lot of dienes are contained in the unleaded gasoline composition, the stability of the unleaded gasoline composition is deteriorated. According to the present invention, the diene number of the unleaded gasoline composition is limited to a low level, the sulfur content is 10 mass ppm or less, the olefin content is 5 to 30% by volume, and occupies the total carbon number = By setting the ratio of CH ₂ carbon to less than 1%, it becomes possible to maintain a high RON, so that the stability is high, the exhaust gas purification treatment load is low, and high driving performance can be ensured. The effect of.

[Unleaded gasoline composition]
In the unleaded gasoline composition of the present invention, the total sulfur content is 10 mass ppm or less, the olefin content is 5 to 30% by volume, the diene value is 0.3 g / 100 g or less, and the proportion of the CH ₂ carbon number to the total carbon number is It is less than 1% and the research octane number is 89 or more.

The diene value as used in the field of this invention refers to the diene value measured by UOP326-82. = The ratio of the number of CH ₂ carbons to the total number of carbons is, for example, in ¹³ C nuclear magnetic resonance ( ¹³ C-NMR) spectrum: a signal derived from = CH ₂ carbon and a signal derived from all carbons of an unleaded gasoline composition It can be calculated from the area ratio. ^When the ratio of carbon number is quantified in the ¹³ C-NMR spectrum, it is preferable to measure by the decoupling method from which the nuclear overhauser effect (NOE) is removed in order to ensure the quantification (Kazuo Tsutsuo, Takashi Takeuchi). Hito, Kenichi Yoshikawa, “How to Use Practical NMR-CW / FT NMR”, p.119, Kodansha Scientific (1984)). The signal derived from = CH ₂ carbon shows a chemical shift of 105.0-116.6 ppm relative to tetramethylsilane (0 ppm).

When the olefin content of the unleaded gasoline composition is less than 5% by volume, the blending amount of the cracked gasoline base material is limited, the production cost of the unleaded gasoline composition increases, and it becomes difficult to secure sufficient RON. . If the olefin content exceeds 30% by volume, the oxidation stability of the unleaded gasoline composition is deteriorated, so that a large amount of an antioxidant is required to ensure oxidation stability. When the diene value exceeds 0.3 g / 100 g, the unleaded gasoline composition is easily subjected to oxidation and polymerization reaction, and the stability is deteriorated. Therefore, it is necessary to increase the additive amount for the prevention. When the diene value is 0.3 g / 100 g or less and the ratio of the ═CH ₂ carbon number to the total carbon number is 1% or more, it is difficult to secure sufficient RON. If RON is less than 89, sufficient driving characteristics of a gasoline vehicle cannot be secured.

  The unleaded gasoline composition of the present invention has a total sulfur content of 10 mass ppm or less, preferably 5 mass ppm or less, particularly preferably 3 mass ppm or less. By setting the total sulfur content to 10 mass ppm or less, it is possible to reduce the load on the exhaust gas treatment catalyst of a gasoline vehicle and also reduce the load on the environment.

  The RON of the unleaded gasoline composition of the present invention is 89 or more, preferably 92 or more, more preferably 93 to 102. With such a high RON, the acceleration and fuel consumption of a gasoline vehicle can be improved.

  In the unleaded gasoline composition according to the present invention, the lead vapor pressure (RVP) is preferably set to 93 kPa or less in order to reduce the amount of gasoline vapor released to the atmosphere, and the startability of the gasoline automobile is improved. In order to maintain it, it is preferable to set it as 44 kPa or more. It is more preferable that this RVP is adjusted according to the season in relation to the outside air temperature, and is 44 to 65 kPa in summer and 70 to 93 kPa in winter.

  The unleaded gasoline composition of the present invention preferably has a 50% by volume distillation temperature of 75 to 105 ° C, more preferably 75 to 100 ° C. If the 50% by volume distillation temperature is less than 75 ° C., the RVP of the unleaded gasoline composition increases, which is not preferable. If it exceeds 105 ° C., the acceleration performance of the gasoline vehicle deteriorates, which is not preferable.

  The unleaded gasoline composition of the present invention preferably has an aromatic content of 40% by volume or less, more preferably 30% by volume or less, and particularly preferably 20 to 30% by volume. If the aromatic content is less than 20% by volume, the blending amount of the cracked gasoline base material is limited, and the production cost of the unleaded gasoline composition becomes high, which is not preferable. If it exceeds 40% by volume, the flammability of the unleaded gasoline composition deteriorates, which is not preferable.

In the unleaded gasoline composition of the present invention, the ratio of the unsaturated carbon number to the total carbon number is preferably 45% or less, more preferably 20 to 40%. When the ratio of the unsaturated carbon number to the total carbon number is in such a range, it becomes easy to secure the olefin content and aromatic content in the above range. In the unleaded gasoline composition of the present invention, the proportion of the ═CH ₂ carbon number to the unsaturated carbon number is preferably 3% or less, more preferably 2.5% or less. = The ratio of CH ₂ carbon atoms occupying the unsaturated carbon atoms exceeds 3%, it is difficult to satisfy both the diene value and RON of the above-described range. The ratio of the number of unsaturated carbon atoms to the total number of carbon atoms is, for example, a signal derived from carbon having a chemical shift of 105.0 ppm or more and lead-free in ¹³ C-NMR spectrum with reference to tetramethylsilane (0 ppm). It can be calculated from the area ratio of signals derived from the total carbon of the gasoline composition.

In the method for producing an unleaded gasoline composition of the present invention, the whole or part of the cracked gasoline fraction is brought into contact with a catalyst containing at least one metal selected from Group 8 elements in the periodic table in the presence of hydrogen. The process obtained in Step A, including a step of reducing the diene value and the proportion of CH ₂ carbon in the total number of carbons more than the decrease in the proportion of unsaturated carbons in the total number of carbons (Step A) Oil is combined with a gasoline base derived from other cracked gasoline fractions (also referred to as “cracked gasoline base” including the treated oil obtained in step A), and these are blended in an amount of 30% by volume or more. An unleaded gasoline composition having a predetermined property and composition.

[Cracked gasoline fraction]
The cracked gasoline fraction in the method for producing an unleaded gasoline composition of the present invention is a petroleum fraction, petroleum refined process oil, petrochemical process oil, coal liquefied oil, oil sand, oil shale, polyolefins, plastics, waste plastics This refers to a fraction having approximately 4 or more carbon atoms and a boiling point of 250 ° C. or less obtained by decomposing hydrocarbons such as Typical processes for obtaining cracked gasoline fractions include catalytic cracking processes and thermal cracking processes. A fraction having a carbon number of about 4 or more and a boiling point of 250 ° C. or less produced as a by-product from a cracking process such as naphtha, kerosene or light oil for obtaining olefins such as ethylene and propylene is also a cracked gasoline fraction of the present invention. Can be preferably used. A dewaxed gasoline fraction obtained from a catalytic dewaxing process that selectively decomposes normal paraffin compounds contained in order to improve the low temperature fluidity of light oil and lubricating oil can also be preferably used as the cracked gasoline fraction of the present invention. . In the present invention, two or more cracked gasoline fractions may be used.

[Catalytic cracking gasoline fraction]
In the method for producing an unleaded gasoline composition of the present invention, a catalytic cracked gasoline fraction is typically used as the cracked gasoline fraction. The process for producing the catalytic cracking gasoline fraction does not particularly limit the catalytic cracking apparatus, the feedstock, and the operating conditions, and any known production process can be employed. The catalytic cracker uses a catalyst such as amorphous silica alumina, zeolite, etc., in addition to petroleum fractions from light oil to vacuum gas oil, while it is obtained from the heavy oil indirect desulfurization unit, the direct desulfurization unit obtained from the degasification oil and 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. The catalytic cracking raw material oil uses a fraction whose sulfur content is reduced to 4000 mass ppm or less, more preferably 2000 mass ppm or less, further 1000 mass ppm or less, particularly 500 mass ppm or less by hydrorefining or the like. It is preferable. For example, UOP catalytic cracking method, flexi cracking method, ultra ortho flow method, fluid catalytic cracking method such as Texaco fluid catalytic cracking method, residual oil fluid catalytic cracking method such as RCC method, HOC method, etc. Petroleum refining process, p.125-156, Kodansha Scientific (1998)).

[Heavy oil pyrolysis gasoline fraction]
In the method for producing an unleaded gasoline composition of the present invention, a heavy oil pyrolysis gasoline fraction can also be preferably used as the cracked gasoline fraction. A heavy oil pyrolysis gasoline fraction is a fraction having a carbon number of approximately 4 or more and a boiling point of 250 ° C. or less obtained by a reaction based on a radical reaction by applying heat to the heavy oil fraction. For example, a fraction obtained by a delayed coking method, a visbreaking method or a fluid coking method (edited by the Japan Petroleum Institute, Petroleum Refining Process, p.193-208, Kodansha Scientific (1998)).

[Process A]
In step A of the method for producing an unleaded gasoline composition of the present invention, the whole or part of the cracked gasoline fraction is preferably added to an inorganic porous carrier such as alumina in the presence of hydrogen, preferably a group 8 element of the periodic table. The diene value and the proportion of ═CH ₂ carbon in the total number of carbons are reduced by contacting with a catalyst supporting at least one metal selected from In this step, the diene content is reduced, and the terminal olefin compound having a relatively low RON is converted into an internal olefin compound having a relatively high RON. Usually, since the cracked gasoline fraction contains sulfur, a catalyst containing nickel or cobalt having high resistance to sulfur is preferred. There are no particular restrictions on the active component elements other than the Group 8 element contained in the catalyst, but molybdenum, tungsten, and phosphorus are listed as preferred components that may be included. As reaction conditions, the diene number of the obtained cracked gasoline fraction is reduced and the proportion of = CH ₂ carbon in the total number of carbons is reduced, but RON hydrogenation can be advanced significantly to reduce RON significantly. It is necessary to set not to. Preferred reaction conditions are a reaction temperature of 40 to 300 ° C., a reaction pressure of 0 to 4 MPa, LHSV of ¹ to 10 h ⁻¹ , and a hydrogen / oil ratio of ¹ to 500 NL / L. In step A, the diene value of the cracked gasoline fraction is preferably 0.5 g / 100 g or less, more preferably 0.3 g / 100 g or less, and particularly 0.1 g / 100 g or less. In Step A, the proportion of CH ₂ carbon in the total carbon number of the cracked gasoline fraction is preferably 3% or less, more preferably 2.5% or less, and particularly 2% or less. Further, in step A, the decrease in olefin content is preferably within 10% by volume, more preferably within 5% by volume, particularly within 3% by volume, and the decrease in RON is within 1%, preferably 0%. Within 0.5, more preferably within 0.3, especially within 0.2. In addition, when performing the process A simultaneously with the process B, the yield of each cracked gasoline fraction obtained by fractional distillation is weighted and averaged to account for the above-mentioned diene value and total carbon number = CH _2. It is preferable to satisfy preferable conditions regarding the ratio of carbon, olefin content, and RON.

The method for reducing the diene number is preferably a method in which the catalyst and catalytically cracked gasoline are brought into contact with each other in the presence of hydrogen, and the diene is converted into a monoolefin, or the sulfur compound coexisting with the diene is reacted and converted into sulfides. . By using a catalyst containing a Group 8 element and applying the preferred reaction conditions described above, the proportion of = CH ₂ carbon in the total number of carbons can be increased without significantly reducing the RON by significantly promoting the hydrogenation of the olefin at the same time. Can be reduced.

Conventionally, in petroleum refining, diene in olefins has been selectively hydrorefined and can be applied as step A in the present invention. Specifically, the IFP Selective Hydrogenation process, the Hules Selective Hydrogenation process, and the like are preferably used (edited by the Japan Petroleum Institute, Petroleum Refining Process, p.62-63, Kodansha Scientific (1998)).
Further, as a method for reducing the diene value in the present invention, the SHU process (21st JPI Petroleum Refining Conference “Recent Progress in Petroleum Process Technology”, 37 (2002)) and the CD Hydro process (NPRA 2001 Annual Meeting, AM-01-39) (2001)) can also be used.

  The method for producing an unleaded gasoline composition of the present invention preferably includes a step of fractionating a cracked gasoline fraction (Step B), and the heavy cracked gasoline fraction obtained in Step B is molybdenum in the presence of hydrogen. Or the desulfurization process (process C) which makes it contact with the catalyst containing tungsten and reduces the total sulfur content of a heavy catalytic cracking gasoline fraction to 20 mass ppm or less is included. Moreover, Preferably, the process (process D) which enlarges the molecular weight of the sulfur compound contained in a cracked gasoline fraction is included. More preferably, the research octane number of the unleaded gasoline composition is 92 or more.

[Process B]
A cracked gasoline fraction, particularly a catalytic cracked gasoline fraction, contains a large amount of an olefin compound having a high RON in a relatively light fraction, but does not contain a large amount of sulfur. On the other hand, the relatively heavy fraction does not contain many olefin compounds having a high RON, but contains a large amount of sulfur. Therefore, in order to effectively use the cracked gasoline fraction, in particular, the catalytic cracked gasoline fraction as the base material of the unleaded gasoline composition, when the total sulfur content of the light cracked gasoline fraction used as the base material is sufficiently low, The light cracked gasoline fraction is preferably not subjected to a desulfurization step as in step C. Thereby, the RON fall of a light cracked gasoline fraction can be suppressed. In step B, the light cracked gasoline fraction and the heavy cracked gasoline fraction are preferably adjusted so that the 10% by volume distillation temperature of the heavy cracked gasoline fraction is 70 to 130 ° C, more preferably 80 to 120 ° C. And fractionate. In order to increase the degree of freedom of blending the base material into the unleaded gasoline composition, the light cracked gasoline fraction and the heavy cracked gasoline fraction are further subdivided into fractions, and the cracked gasoline fraction is divided into three or more fractions. You can fractionate. And it is preferable to apply the process C to the heavy cracked gasoline fraction.

[Process C]
In Step C, the heavy cracked gasoline fraction obtained in Step B is brought into contact with the hydrodesulfurization catalyst in the presence of high-pressure hydrogen. The hydrodesulfurization catalyst contains molybdenum or tungsten, and preferably has molybdenum or tungsten supported on an inorganic porous carrier such as alumina. Although there is no restriction | limiting in particular in component elements other than molybdenum or tungsten which a catalyst contains, Cobalt, phosphorus, potassium, carbon, and nitrogen are mentioned as a preferable component which may be contained. Preferred reaction conditions are a reaction temperature of 150 to 350 ° C., a reaction pressure of 0.1 to 4 MPa, LHSV of ^{1 to} 10 h ⁻¹ , and a hydrogen / oil ratio of 50 to 1000 NL / L. Particularly preferable reaction conditions are a reaction temperature of 200 to 300 ° C., a reaction pressure of ^{1 to} 2.5 MPa, LHSV of 2 to 6 h ⁻¹ , and a hydrogen / oil ratio of 100 to 500 NL / L. The sulfur content of the heavy cracked gasoline fraction obtained in step C is preferably 10 ppm by mass or less, more preferably 5 ppm by mass or less.

[Treatment for increasing the molecular weight of the sulfur compound (Step D)]
The cracked gasoline fraction is subjected to a treatment (step D) for increasing the molecular weight of the contained sulfur compound and used for the fractionation step of step B, or a treatment for increasing the molecular weight of the sulfur compound simultaneously with the fractionation step of step B. It is preferable to carry out. By selectively increasing the molecular weight of sulfur compounds such as thiols, the boiling point of the sulfur-containing compound increases, so that the sulfur-containing compound can be transferred into the heavy cracked gasoline fraction during the fractionation process. The sulfur content of the light cracked gasoline fraction obtained in the fractionation step can be reduced.

  Conventionally, in petroleum refining, sweetening for treating thiols to make the product non-brominated is performed, 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 of increasing the molecular weight of the sulfur compound. Specifically, the Marlox method, the doctor method, etc. are preferably used (Oil Refinery Technical Handbook 3rd edition, Sangyo Tosho Co., Ltd. (1981)).

  In the present invention, as a method for increasing the molecular weight of the sulfur compound, a method of reacting the sulfur compound contained in the cracked gasoline fraction with olefins is also preferably used. Specifically, the methods described in Patent Documents 2 to 6 and the methods described in “Production of Low Sulfur Gasoline and Diesel Fuels: Tier 2 and Beyond”, Petroleum Refining Technology Seminar August 2001, 11-18 can be mentioned. Further, it is particularly preferable to use a process capable of simultaneously performing the treatment for increasing the molecular weight of the sulfur compound and the diene reduction treatment, that is, the step A and the step D can be performed simultaneously. Specifically, the above-described SHU process is preferably used. Furthermore, it is more preferable to use a process capable of simultaneously performing the treatment for increasing the molecular weight of the sulfur compound and the diene reduction treatment while performing fractional distillation, that is, the step A, the step B, and the step D can be performed simultaneously. Specifically, the above-described CD-Hydro process is preferably used.

[Process flow to obtain gasoline base material from cracked gasoline fraction]
In order to obtain a gasoline base material from a cracked gasoline fraction in the method for producing an unleaded gasoline composition of the present invention, when applying the four steps of Step A to Step D, the order of the steps and a plurality of steps are performed simultaneously. Various process flows are possible, but as a particularly preferable process flow, the process flow shown in the block diagram of (a), (b), or (c) is illustrated in FIG. (A) is preferable when performing all four processes of process A-process D separately. (B) is preferable when the process A and the process D are performed simultaneously. (C) is preferable when performing Step A, Step B and Step D simultaneously.

[Other gasoline bases derived from non-cracked gasoline fractions]
Other gasoline bases derived from non-cracked gasoline fractions mixed in the blending process include catalytic reformed gasoline bases, alkylate gasoline bases, straight-run naphtha desulfurized bases, and isomerized gasoline bases. , Oxygen-containing gasoline base materials such as toluene, xylene and methyl t-butyl ether (MTBE), ethyl t-butyl ether (ETBE), ethyl i-butyl ether (EIBE), t-amyl ethyl ether (TAEE), ethanol, methanol, etc. A well-known gasoline base material can be used. The other gasoline base material mixed in the blending step has a sulfur content of 20 mass ppm or less, preferably 10 mass ppm or less, more preferably 3 mass ppm or less, and particularly preferably 1 mass ppm or less. When the sulfur content of other gasoline bases exceeds 20 mass ppm, the blending amount in the blending step of the gasoline bases is restricted, which is not preferable.

  Preferred blending amounts are 30 to 90% by volume of cracked gasoline fraction, particularly 40 to 80% by volume, 5 to 50% by volume of catalytically reformed gasoline base, particularly 10 to 45% by volume, alkylate gasoline base 5 to 40% by volume, particularly 10 to 30% by volume.

〔Additive〕
Furthermore, the unleaded gasoline composition of the present invention can be blended with 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 mass% 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.

  Hydrocracked gas oil fraction of Middle Eastern crude oil and hydrorefined residue of atmospheric distillation residue are mainly used as feedstock for catalytic cracked gasoline fraction A obtained by fluid catalytic cracking. Then, it was processed by an oxidation type sweetening device to obtain catalytic cracking gasoline fraction B. Table 1 shows the properties of the catalytic cracking gasoline fractions A and B.

  The density is JIS K 2249, the vapor pressure (Lead method) is JIS K 2258, the distillation property is JIS K 2254 (normal pressure method), the hydrocarbon component composition is JIS K 2536 (fluorescent indicator adsorption method), and the diene value is UOP 326. 82, sulfur content was measured according to ASTM D 5453 (ultraviolet fluorescence method). RON was measured by a gas chromatograph method using a PIONA device manufactured by Hewlett-Packard Company.

  This catalytic cracking gasoline fraction B was fractionated to obtain a light catalytic cracking gasoline fraction C and a heavy catalytic cracking gasoline fraction D.

A catalyst in which 20% by mass of nickel is supported on alumina is charged into a fixed bed flow reactor and subjected to sulfidation, and then the reaction temperature is 250 ° C., the reaction pressure is normal pressure, the liquid space velocity is 4 h ⁻¹ , and the hydrogen / oil ratio is 340 NL / L Under these conditions, light catalytic cracking gasoline fraction C was passed through to reduce diene and light catalytic cracking gasoline E was obtained.

A catalyst having cobalt, molybdenum and phosphorus supported on alumina (cobalt content 2.4% by mass, molybdenum content 9.4% by mass, phosphorus content 2.0% by mass) was charged into a fixed bed flow reactor. After sulfiding, the heavy catalytic cracking gasoline fraction D was passed through under conditions of reaction temperature 250 ° C., reaction pressure 1.0 MPa, LHSV = 5.0 h ⁻¹ , H ₂ / OIL = 307 NL / L. Hydrodesulfurization was performed to obtain heavy catalytic cracked gasoline F.

Properties of light catalytic cracking gasoline fractions C and E are shown in Table 2. Table 3 shows the properties of heavy catalytic cracking gasoline fractions D and F.

For measurement of the ¹³ C-NMR spectrum, a JSX GSX270 NMR apparatus was used. Deuterated chloroform was used as a solvent, and tetramethylsilane (0 ppm) was used as an internal standard for chemical shift. Analysis for quantification by carbon species classification was performed in SGNNE mode with data points of 32768 points, observation frequency region width of 27027 Hz, pulse width of 2 μs, pulse waiting time of 30 s, and the number of integrations of 800 times, with a broadening factor of 1.5 Hz. This was done by taking the integral ratio of the signal of the spectrum that was Fourier transformed with. The region of 5.0 to 55.0 ppm was assigned to saturated carbon, the region of 105.0 to 155.0 ppm was assigned to unsaturated carbon, and the total was taken as the total carbon of the sample. Further, the region of 105.0 to 116.6 ppm was attributed to ═CH ₂ carbon and quantified. The signal in the region of 105.0 to 116.6 ppm was confirmed to be derived from carbon to which two hydrogens were bonded by the DEPT method.

Light catalytic cracking gasoline fraction C had a diene value of 1.7 g / 100 g and accounted for 2.5% of the total carbon number = CH ₂ carbon, but light catalytic cracking gasoline E had a diene value of 0.1 g. / less than 100 g, the ratio of = CH ₂ carbons to the total number of carbon becomes 1.3%, the diene is substantially removed, the proportion of = CH ₂ carbons to the total number of carbon atoms was decreased significantly, RON is The light catalytic cracking gasoline fraction C was 93.9, and the light catalytic cracking gasoline E was 93.8. The proportion of unsaturated carbon in the total carbon number of the light catalytic cracking gasoline fraction C was 21.1%, but that of light catalytic cracking gasoline E was 20.5%. In the process of converting light catalytic cracking gasoline fraction C to light catalytic cracking gasoline E, the reduction of CH ₂ carbon is larger than the reduction of unsaturated carbon. It can be said that a part has changed to a carbon-carbon double bond inside the carbon chain.

Gasoline substrates obtained by known techniques other than catalytic cracking include desulfurized straight-run naphtha G, catalytic reforming medium oil H, catalytic reforming heavy oil I, alkylate gasoline J, and their properties are shown in Table 4. It is as follows. The catalytically modified medium oil H is obtained by distilling and separating a fraction rich in toluene 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.

  Desulfurization straight-run naphtha G is 5.0% by volume, catalytic reforming medium oil H is 9.0% by volume, catalytic reforming heavy oil I is 5.0% by volume, and alkylate gasoline J is 8.0% by volume. Then, 45.0 vol% of light catalytic cracking gasoline fraction E described in Example 1 and 28.0 vol% of heavy catalytic cracking gasoline F described in Example 1 were blended to prepare an unleaded gasoline composition K.

  For comparison, an unleaded gasoline composition L was prepared in the same manner as in Example 2 except that the light catalytic cracking gasoline fraction C was used instead of the light catalytic cracking gasoline fraction E.

  Desulfurization straight-run naphtha G is 3.0% by volume, catalytic reforming medium oil H is 19.0% by volume, catalytic reforming heavy oil I is 10.0% by volume, and alkylate gasoline J is 23.0% by volume. And 45.0 volume% of light catalytic cracking gasoline E of Example 1 was mix | blended, and the unleaded gasoline composition M was prepared.

No additives such as oxidation stabilizers were added to the unleaded gasoline compositions K, L and M. Properties of the prepared unleaded gasoline compositions K, L and M are shown in Table 5.

  It is clear that the unleaded gasoline composition K provided by the present invention can reduce the diene content with almost no other change compared to the unleaded gasoline composition L provided by the prior art.

FIG. 3 is a block diagram illustrating a preferred process flow for obtaining a gasoline base material from cracked gasoline fractions.

Claims (6)

The total sulfur content is 10 mass ppm or less, the olefin content is 5 to 30% by volume, the diene value is 0.3 g / 100 g or less, and the number of CH ₂ carbons (= CH ₂ carbons) having carbon-carbon double bonds is the total number of carbons. An unleaded gasoline composition having a proportion of less than 1% and a research octane number of 89 or more.   The unleaded gasoline composition according to claim 1, which has a research octane number of 92 or more. In the presence of hydrogen, all or part of the cracked gasoline fraction is contacted with a catalyst containing at least one metal selected from Group 8 elements of the periodic table to reduce the diene number and to increase the total carbon number. occupied = CH ₂ comprising the step of greatly reducing than the decrease in the proportion of the unsaturated carbon atoms of the ratio of the number of the total number of carbon atoms (step a), cracked gasoline fraction which process oil obtained was included in step a The total sulfur content is 10 mass ppm or less, the olefin content is 5 to 30% by volume, the diene value is 0.3 g / 100 g or less, and the total carbon number Is a method for producing an unleaded gasoline composition having a CH ₂ carbon ratio of less than 1% and a research octane number of 89 or more.   A step of fractionating the cracked gasoline fraction (step B), and contacting the heavy cracked gasoline fraction obtained in step B with a catalyst containing molybdenum or tungsten in the presence of hydrogen to cause heavy cracked gasoline fraction The method for producing an unleaded gasoline composition according to claim 3, further comprising a desulfurization step (step C) for reducing the total sulfur content of the catalyst to 20 ppm by mass or less.   The method for producing an unleaded gasoline composition according to claim 4, further comprising a step (step D) of increasing the molecular weight of the sulfur compound contained in the cracked gasoline fraction.   The research method octane number of an unleaded gasoline composition is 92 or more, The manufacturing method of the unleaded gasoline composition of Claims 3-5.

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