METHOD FOR THE PREPARATION OF A FUEL COMPOSITION FOR USE IN GASOLINE ENGINES AND BLENDING COMPONENT

Abstract

A method for the preparation of a fuel composition for use in gasoline engines and a blending component is provided, in which the fractions from cracking apparatus is used. In the method, light cycle oil obtained from fluid catalytic apparatus is subjected to fractionation and used as a blending component. The blending component obtained by fractionation has a distillation characteristic of from 160 to 230° C., a content of aromatic hydrocarbons with 9 or more carbon atoms of amount not less than 80% by volume and an indane content of amount not less than 20% by volume.

Description

This invention relates to a method for preparation of fuel compositions for use in gasoline engines as used by the gasoline engines installed in automobiles and the like, and to a blending component for fuels used in automotive engines.

Fluid catalytic cracking has been widely adopted as a process to obtain as far as possible the so-called white oils (blending components for gasoline fuels, light oil fuels and so on) that are much in demand by society. With vacuum gas oils and residual oils as the raw material, this fluid catalytic cracking apparatus can produce mainly gasoline and middle distillates of high octane number, and light olefins. Of the products produced by this method, the fractions with a distillation characteristic of approximately 30 to 200° C. are known as cracked gasolines, or as FCC gasolines after the fluid catalytic cracking (FCC) process, and are used as major blending components of fuel compositions for use in gasoline engines. Fractions of boiling points higher than cracked gasolines are further fractionated into light fractions (distillation characteristic up to 380° C.) in order to obtain middle fractions, and recovered as light cycle oil (hereinafter referred to as LCO). This LCO is utilised mainly as a blending component for heavy oil “A”, but because it has a low cetane number the situation is that there are constraints on its use as a blending component for heavy oil “A” in diesel engines.

There have therefore been attempts to make effective use of this LCO as a fuel for automotive engines. For example, Japanese Laid-open Patent Specification No. 2008-127542 discloses a method for the preparation of a blending component for fuels used in gasoline engines in which LCO is contacted with a specified crystalline aluminosilicate zeolite catalyst under certain reaction conditions. However, the LCO is further hydrocracked in the disclosed procedure, so that there is a problem in that further plant investment and utility costs are required, making it more expensive. In addition, because the characteristics which are necessary during compounding of the gasoline, in particular the distillation characteristics which impact on driving performance of the automobiles, have not been disclosed, it is unclear what the impact on driving performance is.

Therefore, the present invention has as its objective to offer a fuel composition preparation method in which the fractions from cracking apparatus can be used effectively for fuel compositions for use in gasoline engines, and a blending component for fuels used in automotive engines which uses this method of preparation.

In the method for preparation of fuel compositions for use in gasoline engines relating to this invention, light cycle oil (LCO) produced by fluid catalytic cracking apparatus is subjected to fractionation and incorporated as a blending component.

In this invention, light cycle oil (LCO) has the meaning of a fraction, being produced in a catalytic cracking apparatus and being a kerosene fraction known as a middle distillate, with a distillation characteristic of up to 380° C.

It is preferable if the distillation characteristic of the blending component obtained by means of the aforementioned fractionation is from 160 to 230° C., the content of aromatic hydrocarbons with 9 or more carbon atoms is of amount not less than 80% by volume and the indane content is of amount not less than 20% by volume. What is meant by an indane is such as 2,3-dihydroindene (indane) optionally substituted by at least one functional group which is a hydrocarbon such as an alkyl group, preferably a C₁- to C₄-alkyl group.

In the present invention, there is no particular restriction on the number of carbon atoms in the alkyl group bonded to the indane or on the number of groups, but it is preferable if the number of carbon atoms in the total indane molecule is not more than 12. If the number of carbon atoms is more than 12, the heavy fractions in the blending component of the gasoline engine fuel obtained will increase and the distillation end point will increase, which is not desirable. As specific examples of indanes, mention may be made of 2,3-dihydroindene (indane), 5-methylindane, 4-methylindane, 1,2-dimethylindane, 1,3-dimethylindane, 1,4-dimethylindane, 1,5-dimethylindane, 1,6-dimethylindane, 1,7-dimethylindane, 1,4,5-trimethylindane, 1,4,6-trimethylindane, 2,4,5-trimethylindane, and 2,4,6-trimethylindane.

Also, the blending component for automotive engine fuels of the present invention is one that can be used in the method for preparation of fuel compositions for use in gasoline engines of the present invention. In other words, it satisfies the condition that it is obtained by fractionation of light cycle oil obtained from fluid catalytic cracking apparatus, and the distillation characteristic is in the range of from 160 to 230° C., a content of aromatic hydrocarbons with 9 or more carbon atoms is of amount not less than 80% by volume and an indane content of amount not less than 20% by volume.

By means of the present method for preparation of fuel compositions for use in gasoline engines, it is possible to satisfy the characteristics required of a fuel composition for use in gasoline engines, because LCO, which has not been used in gasoline hitherto, is fractionated and blended as a component which has a high (at least 93) research octane number (hereinafter RON), and it is thus possible to make more effective use of fractions from cracking apparatus. By incorporating the blending component (hereinafter referred to as LLCO) obtained by fractionation of the LCO, it is possible to effect an improvement in drivability and acceleration properties of fuel compositions for use in gasoline engines. In addition there is the advantage that it is possible to improve fuel consumption by increasing the per-volume calorific heat.

The fractionation conditions for LCO should be set as appropriate by taking into account the balance of LCO characteristics and other blending components. In the case where LLCO is obtained by fractionation of ordinary LCO, the content of aromatic hydrocarbons with not less than 9 carbon atoms is in the amount of approximately 70 to 90% by volume, and the indane content is about 15 to 25% by volume. From the standpoint of high-speed acceleration properties and fuel consumption, it is preferable if the LLCO cut temperature is made higher, but if the distillation end point exceeds 230° C., there will be undesirable problems in that the fuel composition for use in gasoline engines will be made excessively heavy, or the proportion that can be blended in will be restricted.

The proportion of LLCO in the blend can be suitably set in the range of from 4 to 10% by volume so that the characteristics of the gasoline-engine fuel composition will be within the desired ranges, but given that its distillation characteristics are heavier than for gasoline-engine fuel compositions, in order to satisfy the JIS standard for automobile gasolines (JIS K 2202), it is necessary in particular to limit the proportion in the blend so that the distillation temperature at 90 vol % distilled (T90) is not more than 180° C. and further that the distillation end point (EP) is not more than 220° C. It is also necessary to minimise impact on practical performance as an automotive gasoline engine fuel. Accordingly, the preferred blend proportion is in the range of from 4 to 7% by volume.

The blending component for automotive engine fuels relating to this invention is one that has a distillation characteristic of in the range of from 160 to 230° C., a content of aromatic hydrocarbons with 9 or more carbon atoms of amount not less than 80% by volume, and an indane content of amount not less than 20% by volume, and corresponds to the already mentioned LLCO. Also as already mentioned, it can be obtained by further fractionation of light cycle oil corresponding to the kerosene fraction known as middle distillates. This LLCO has a high RON of at least 93, and so satisfies the characteristics required of fuel compositions for the gasoline engines being manufactured. It makes it possible to recover more fractions from cracking apparatus and to produce the blending component for gasoline-engine fuel compositions. Because it also contains many indanes, it can also improve the acceleration properties at high speeds, and because the per-volume calorific value is at least 11% higher than commercial gasoline fuels, it is possible to improve fuel consumption. Also, whilst containing many heavy aromatic hydrocarbons, it contains hardly any existent gum in comparison with fractions obtained from reformates of similar distillation characteristics, so that it has the advantage of having no effect on the amounts of other additives such as detergents.

In method of the present invention, the LLCO should be blended as a component together with ordinary gasoline blending components. As examples of ordinary gasoline blending components, mention may be made of the following.

“Desulphurised Light Naphtha”

This is a blending component obtained by desulphurisation of a naphtha obtained from a crude oil atmospheric distillation apparatus, and then by separation into low boiling point fractions by means of distillation.

“Isomerised Gasoline”

This is a blending component obtained by isomerisation of the aforementioned desulphurised light naphtha.

“Catalytic Reformate”

This is a blending component obtained by desulphurisation of a naphtha obtained from a crude oil atmospheric distillation apparatus and reforming of the remaining heavy fraction separated off by distillation of the aforementioned desulphurised light naphtha, using for example a catalytic reforming method such as Platforming.

“Debenzenated Light Catalytic Reformate”

This is a blending component obtained by separating the aforementioned catalytic reformate into fractions with a boiling point lower than benzene by means of distillation.

“Raffinate Fraction”

This is a blending component obtained by further distillation of a heavy catalytic reformate obtained by fractionation in the form of fractions with a high boiling point by means of distillation from the aforementioned catalytic reformate, and by taking the fractions obtained by separation of fractions which contain benzene therefrom as the remainder from which the benzene is extracted and removed by using, for example, a solvent such as Sulfolane.

“Catalytic Reformates with 7 Carbon, 8 Carbon, or 9 or More Carbon Atoms”

These are blending components obtained by further distillation of a heavy catalytic reformate obtained by fractionation in the form of fractions with a boiling point higher than benzene by means of distillation from the aforementioned catalytic reformate, and fractionation into fractions that contain mainly aromatics with 7 carbons, aromatics with 8 carbons and aromatics with 9 or more carbons.

“Catalytically Cracked Gasoline”

This is a blending component obtained by catalytically cracking heavy oil.

“Thermally Cracked Gasoline”

This is a blending component obtained by thermally cracking heavy oil.

“Light Catalytically Cracked Gasoline and Desulphurised Heavy Catalytically Cracked Gasoline”

These are blending components obtained by distillation of the aforementioned catalytically cracked gasoline obtained by catalytic cracking of heavy oil to separate it into fractions with a low boiling point and fractions with a high boiling point. In the case of the light fractions, the blending component is the result of treating the foul-smelling light sulphur compounds such as mercaptan by sweetening methods such as the Merox method. In the case of the heavy fractions, the blending component is the result of removing the sulphur component while ensuring that the reduction in the octane number through olefin hydrogenation is minimised, by using a selective desulphurisation method such as Prime-G+.

“Light Thermally Cracked Gasoline and Heavy Thermally Cracked Gasoline”

These are blending components obtained by separation into fractions with a low boiling point and fractions with a high boiling point by distilling the aforementioned thermally cracked gasoline obtained by thermally cracking heavy oil.

“Alkylate”

This is a blending component obtained by addition of lower olefins (alkylation) obtained as a by-product from catalytic cracking apparatus to hydrocarbons such as isobutane.

“Butane/Butylene Fraction”

This is a blending component obtained by refining petroleum gases obtained as a by-product from apparatus such as atmospheric distillation apparatus, naphtha desulphurisation apparatus, catalytic reforming apparatus or catalytic cracking apparatus.

“Oxygenates Such as Alcohols or Ethers”

Mention may be made specifically of, for example, methanol, ethanol and propanol for alcohols. As examples of ethers mention may be made of MTBE (methyl tertiary butyl ether) and ETBE (ethyl tertiary butyl ether).

The types of gasoline blending components used are selected as appropriate to conditions such as the make-up of the apparatus at the refinery. There is no need for all the types of blending component to be mixed in. Consequently, the proportion of any types not used is 0% by volume. Also, when the sulphur content of the LLCO obtained by fractionation of LCO is high, it is possible to carry out, as needed, a desulphurisation treatment such as hydrorefining or adsorption desulphurisation.

EXAMPLES

LCO obtained from a catalytic cracking apparatus was further separated in a distillation apparatus into light fractions and heavy fractions. A light-fraction LLCO with a distillation characteristic of initial boiling point to 230° C. was obtained. A fuel composition for use in gasoline engines was compounded by blending the LLCO in a commercial premium gasoline (PG) and a commercial regular gasoline (RG). Table 1 shows the characteristics of the LLCO, and Tables 2 and 3 show the characteristics of fuel compositions for use in gasoline engines which included the LLCO (Embodiments 1 to 4 and Comparative Example 1). Tables 2 and 3 also show, in the form of Comparative Examples 2 and 3, the characteristics of the PG and the RG used in the compounding.

The methods of measurement of the properties shown in Tables 1 to 3 were as follows.

Density

Measured in accordance with JIS K 2249 “Crude Oil and Petroleum Products—Determination of Density and Density/Mass/Volume Conversion Tables”.

Distillation Characteristic

Measured in accordance with JIS K 2254 “Petroleum Products—Distillation Test Methods”.

Octane Number

Measured in accordance with the method for determination of research octane number of JIS K 2280 “Petroleum Products—Fuel Oils—Determination of Octane Number and Cetane Number, and Method for Calculation of Cetane Index”.

Composition/Aromatics

Measured in accordance with JIS K-2536-2 “Petroleum Products—Method for Determination of Constituents. Part 2: Determination of All Components by Gas Chromatographs”.

Total Calorific Value

Measured in accordance with JIS K 2279 “Crude Oil and Petroleum Products—Method for Determination of Calorific Value and Method for Estimation by Calculation”.

Fuel Consumption

Measured by the TRIAS test method on a chassis dynamo. The test was performed in JCO8 mode (hot start) after sufficient running in warm air. The fuel consumption was calculated from the amount of exhaust gases produced during the test by using a carbon balance equation, and the rate of improvement in fuel consumption was expressed as a relative value, taking the commercial PG and commercial RG fuels as a basis.

Acceleration Properties

Three time spans were set up at intervals of 10 km/h, from 70 km/h to 100 km/h, and the times to reach the respective vehicle speeds were measured on a chassis dynamo. The improvement or deterioration in acceleration properties was evaluated on the basis of the acceleration times for the commercial PG and the commercial RG. In the table, “Good acceleration relative to the standard base fuel” was expressed as “O” (pass), “Same acceleration relative to the standard base fuel” was expressed as “Same”, and “Poor acceleration relative to the standard base fuel” was expressed as “X” (fail)

	TABLE 1
			LLCO
	RON		95.0
	Density	g/cm3	0.8626
	Distillation
	IBP	° C.	166.5
	T10	° C.	178.0
	T30	° C.	183.5
	T50	° C.	189.0
	T70	° C.	195.0
	T90	° C.	202.5
	EP	° C.	225.0
	Composition
	C9+ aromatics	Vol %	82.3
	Indanes
	Indane	Vol %	1.0
	(2,3-dihydroindene)
	Methylindane	Vol %	5.3
	Dimethylindane	Vol %	10.3
	Trimethylindane	Vol %	4.2
	Total	Vol %	20.8
	Total calorific value	J/cm3	39100

TABLE 2
		Emb. 1	Emb. 2	Comp.Ex. 1	Comp. Ex. 2
PG	Vol %	93	96	85	100
LLCO	Vol %	7	4	15
RON		99.3	99.4	98.9	99.6
Density	g/cm3	0.7597	0.7578	0.7708	0.7494
Distillation
IBP	° C.	29.5	29.5	30.5	30.0
T10	° C.	48.5	46.5	50.5	45.5
T30	° C.	71.5	70.0	77.5	67.5
T50	° C.	100.5	97.5	108.0	94.0
T70	° C.	122.0	117.5	136.0	113.5
T90	° C.	168.0	163.0	184.5	155.0
EP	° C.	196.5	189.5	218.5	175.0
Composition
CP+ aromatics	Vol %	20.1	18.1	25.4	15.4
Indanes
Indane (2,3-dihydroindene)	Vol %	0.3	0.2	0.3	0.2
Methylindane	Vol %	0.4	0.2	0.8	0.0
Dimethylindane	Vol %	0.7	0.4	1.5	0.0
Trimethylindane	Vol %	0.3	0.2	0.6	0.0
Total	Vol %	1.7	1.0	3.2	0.2
Total calorific value	J/cm3	35580	35520	36000	35200
Fuel consumption	%	1.3	1.1	—	Base
Acceleration properties		◯	◯	—	Base

TABLE 3
				Comp.
		Emb. 3	Emb. 4	Ex. 3
RG	Vol %	93	96	100
LLCO	Vol %	7	4
RON		90.4	90.1	90.0
Density	g/cm3	0.7466	0.7422	0.7357
Distillation
IBP	° C.	34.5	33.0	33.0
T10	° C.	52.5	51.0	50.5
T30	° C.	72.5	71.0	68.5
T50	° C.	103.0	98.5	94.5
T70	° C.	138.0	132.5	126.0
T90	° C.	180.0	175.5	167.0
EP	° C.	215.5	213.0	213.5
Composition
CP+ aromatics	Vol %	16.7	14.6	11.8
Indanes
Indane	Vol %	0.3	0.2	0.2
(2,3-dihydroindene)
Methylindane	Vol %	0.8	0.7	0.5
Dimethylindane	Vol %	1.2	0.9	0.5
Trimethylindane	Vol %	0.4	0.3	0.1
Total	Vol %	2.7	2.1	1.3
Total calorific	J/cm3	35100	34960	34690
value
Fuel consumption	%	1.3	1.2	Base
Acceleration		◯	◯	Base
properties

As shown in Table 1, it was found that LLCO has a high research octane number. Thus, it is possible to use it as a blending component for gasoline-engine fuel compositions with good acceleration properties during high-speed driving. It was also found that the per-volume calorific value is high compared with commercial gasoline fuels. Thus, it is possible to use it as a blending component for gasoline-engine fuel compositions with good fuel consumption.

Also, for the compounded fuel composition for use in gasoline engines to satisfy the JIS standard for gasoline (JIS K 2202), it is necessary to regulate the blend proportions so that T90 is not more than 180° C. and the EP is not more than 220° C., but, as Table 2 shows, in Comparative Example 1, which includes 15% by volume of LLCO, the distillation temperature at 90 vol % distilled (T90) was found to exceed the 180° C. which is the JIS K 2202 standard. On the other hand, when the proportion of LLCO in the blend was not more than 10% by volume in the case of the PG, or not more than 7% by volume in the case of the RG, there was no impact on practical performance, and it was thus found that it was possible to compound a fuel composition for use in gasoline engines that satisfied the JIS standard.

Furthermore, in the case of Embodiment 1 to 3, in which the content of aromatic hydrocarbons with 9 or more carbon atoms and the content of indanes were higher than in the commercial gasolines (Comparative Examples 2 and 3), it was shown that the acceleration properties at high speeds (70 to 100 km/h) and the fuel consumption were improved.

Claims

1. A method for the preparation of a fuel compositions for use in gasoline engines, comprising subjecting the light cycle oil obtained from a fluid catalytic apparatus to fractionation to produce a blending component and blending said blending component into a fuel composition.

2. The method of claim 1 wherein the distillation characteristic of the blending component obtained by fractionation is from 160 to 230° C., the content of aromatic hydrocarbons with 9 or more carbon atoms is of amount not less than 80% by volume and the indane content is of amount not less than 20% by volume.

3. The method of claim 1, wherein the amount of said blending component is in the range of from 4 to 10% by volume.

4. A blending component for automotive engine fuels, produced by fractionation of light cycle oil obtained from a fluid catalytic cracking apparatus and in that the distillation characteristic is from 160 to 230° C., the content of aromatic hydrocarbons with 9 or more carbon atoms is of amount not less than 80% by volume and the indane content is of amount not less than 20% by volume.

5. The method of claim 2 wherein the amount of said blending component is in the range of from 4 to 10% by volume.