FUEL COMPOSITION OF DIESEL FUEL

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation of US national stage patent application Ser. No. 17/290,424 filed on Apr. 30, 2021, under 35 U.S.C. § 371, of International Patent Application No. PCT/RU2020/000021, filed Jan. 17, 2020, which claims priority to Russian Patent Application 2019112856, filed Apr. 26, 2019 and Russian Patent Application 2019101618, filed Jan. 22, 2019, which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The invention relates to petroleum refining and petrochemistry, namely, to a diesel fuel composition.

BACKGROUND

Diesel fuel remains the most highly-demanded petroleum product both in the worldwide and in the Russian markets. It is mostly consumed by railway, water and road freight transportation, as well as by various electric generators, military and agricultural equipment.

Modern diesel fuel is a deeply hydroprocessed product having various additives, which provide the required environmental and operational properties.

A very important quality in the parameters of diesel fuel that characterizes its volatility is the cetane number, and its optimal value provides good starting properties of fuel, as well as a lesser amount of noxious emissions along with exhaust gases.

In order to enhance the ignition of diesel fuels, ignition promoters are used. Nowadays, additives based on 2-ethylhexyl nitrate are used as the ignition promoters in Russia. However, along with advantages, 2-ethylhexyl nitrate has a number of disadvantages: it is explosion-dangerous, may decompose upon explosion, accelerates the fuel oxidation, comprises nitrogen, corrosive relative to metals, and deteriorates antiwear properties of diesel fuel. It is known that in presence of the ignition promoter based on 2-ethylhexyl nitrate, the concentration of the antiwear additive must be increased in order to achieve the required fuel lubricity. Also, investigators note that the cetane numbers of diesel fuels are reduced in the process of their storage, which is explained by decomposition (by hydrolysis) of 2-ethylhexyl nitrate in the presence of water.

Abroad in view of the limitation of the nitrogen content in diesel fuel, the California Air Resources Board (CARB) implies a successive transition to output of diesel fuels with peroxides.

An additive for a low-sulfur diesel fuel is known in order to reduce the fuel consumption in a diesel engine, characterized in that it comprises peroxide in the amount of from 0.001 wt. % to 10 wt. %.

(Application WO 2016/174176 A1, 2016).

The additive disadvantage lies in an insufficient efficiency in terms of increase of lubricity the diesel fuel lubricity that does not allow the enhancement of this parameter up to the standard requirements.

(U.S. Pat. No. 5,314,511, 1994).

The composition disadvantage lies in a high sulfur content in the fuel composition being up to 500 mg/kg of sulfur, while nowadays, modern diesel fuels comprise up to 10 mg/kg of sulfur. When testing the obtained samples of the fuel composition, an influence of the additive onto the fuel consumption was studied and a toxicity of emissions was evaluated, i.e. environmental properties were evaluated, rather than operational ones.

The closest analogue of the suggested fuel composition is a diesel fuel formulation comprising an additive of premixed cyclohexyl nitrate or 2-ethylhexyl nitrate and peroxides selected from a group of: ditert-butyl peroxide, dicumyl peroxide, cumyl hydroperoxide under a mass ratio of said components from 3:1 to 1:3 in the amount of the additive of 0.1-0.5 wt. %.

(RU Patent No. 2451718, 2012).

This composition disadvantage lies in a presence of the diesel fuel produced according to the GOST 305-82 that is characterized by an increased content of sulfuric compounds (up to 0.05 wt. %). Such diesel fuels have good lubricating properties and do not require adding of antiwear additives. Also, this fuel is produced to supply according to the state defense order only and for export. Also, the formulation of this fuel composition comprises nitrates that does not allow reduction of the content of nitrogen oxides in exhaust gases to the minimum.

SUMMARY

In one aspect of the invention, a fuel composition is provided, where the fuel composition based on a diesel fraction having a sulfur content of less than 10 mg/kg with boiling points in the range of 180-360° C., characterized in that it comprises ignition promoters such as organic peroxides selected from a group of: di-tert-butyl peroxide, 1,1-di(tert-butyl peroxy)cyclohexane, dicumyl peroxide, and an antiwear additive based on carboxylic acids having the following ratio of components, wt. %:

• • organic peroxide from 0.01 to 0.5,
  • antiwear additive from 0.005 to 0.1, diesel fraction up to 100.

In another aspect of the invention, a fuel composition is provided where the fuel composition is based on a diesel fraction having a sulfur content of less than 10 mg/kg with boiling points in the range of 180-360° C., characterized in that it comprises ignition promoters such as organic peroxides selected from a group of: tert-butyl cumyl peroxide, isobutyl cumyl peroxide, n-butyl cumyl peroxide, and an antiwear additive based on carboxylic acids having the following ratio of components, wt. %:

• • organic peroxide from 0.01 to 0.5,
  • antiwear additive from 0.005 to 0.1,
  • fraction up to 100.

In another aspect of the invention, a fuel composition is provided where the fuel composition is based on a diesel fraction having a sulfur content of less than 10 mg/kg with boiling points in the range of 180-360° C., characterized in that it comprises ignition promoters such as organic peroxides selected from a group of: isopropyl cumyl peroxide, ethyl cumyl peroxide, methyl cumyl peroxide, and an antiwear additive based on carboxylic acids having the following ratio of components, wt. %:

• • organic peroxide from 0.01 to 0.5,
  • antiwear additive from 0.005 to 0.1
  • diesel fraction up to 100.

DETAILED DESCRIPTION

A task of the invention is to create a fuel composition of a low-sulfur diesel fuel using organic peroxides as ignition promoters that could meet the requirements of GOST 32511-2013, GOST R 52368-2005, EN 590, GOST R 55475-2013, TR CU 013/2011.

The posed task is solved by the proposed diesel fuel composition including a diesel fraction with a sulfur content of less than 10 mg/kg with boiling points in the range of 180-360° C., characterized in that it comprises a synergistic combination of an organic peroxide as an ignition promoter (up to 0.5 wt. %) and an antiwear additive based on carboxylic acids (up to 0.1 wt. %).

In order to prepare a basic diesel fuel, the following components are used: ultra-low-sulfur (having the sulfur content of less than 10 mg/kg)=hydroprocessed diesel fraction and/or a hydrocracking diesel fraction with boiling points in the range of 180-360° C.

The proposed diesel fuel is prepared using a standard equipment by mixing components and additives until a homogeneous product is obtained.

Characteristics of the diesel fuel components, which are used in examples to support the proposed invention, are shown in Table 1.

As examples of the proposed invention, the diesel fuel compositions were prepared, with their test results stated in Tables 2, 3 and 4, wherein results of testing the diesel fuel comprising 2-ethylhexyl nitrate as the ignition promoter are provided for comparison.

The test results show that the diesel fuel samples comprising organic peroxide as the ignition promoter are highly competitive, in terms of an increment of the cetane numbers, with diesel fuels comprising 2-ethylhexyl nitrate as the ignition promoter.

The combination of the additives' package in the formulation of the diesel fuel, where the package comprises an organic peroxide and the antiwear additive based on carboxylic acids, has a synergistic effect in terms of the lubricity of the fuel. Table 2 states experimental values of the corrected wear scar diameter according to the HFRR method for each diesel fuel sample. For comparison, the tables also state data regarding the lubricity of the diesel fuel samples, which comprise 2-ethylhexyl nitrate as an ignition promoter, while the formulation and concentration of the antiwear additive remain unchanged. Unexpectedly, it has been found that the peroxide additive in the package with the antiwear additive based on carboxylic acids does not negatively affect the lubricity of the diesel fuel as opposed to 2-ethylhexyl nitrate. The distinctive feature of the invention is the synergistic effect that is observed in case of the combined use of the organic peroxides as ignition promoters and the antiwear additive based on carboxylic acids in the diesel fuel (having the sulfur content of less than 10 mg/kg).

It is known that 2-ethylhexyl nitrate facilitates formation of resinous compounds in diesel fuels and acceleration of the fuel oxidation. The obtained data (Table 2) allow to conclude that the ignition promoters based on organic peroxides have less impact onto formation of a residue. This is advantageous as compared to the ignition promoters based on 2-ethylhexyl nitrate. The number of adsorption resins in fuels comprising ignition promoters based on organic peroxides and 2-ethylhexyl nitrate are commensurable and fall within limits of the method reproducibility.

The effective combination of the ignition promoters based on organic peroxides and the antiwear additive based on carboxylic acids may allow to reduce the concentration of the latter one. This is an advantage as compared to the ignition promoters based on 2-ethylhexyl nitrate, which, when they are used, make it necessary to increase the concentration of the antiwear additive in order to achieve the required lubricity.

Therefore, the proposed diesel fuel composition allows to produce the diesel fuel that meets the requirements of GOST 32511-2013, GOST R 52368-2005, EN 590, GOST R 55475-2013 and TR CU 013/2011 in terms of quality parameters.

TABLE 1
Main characteristics of the diesel fuel components

	Hydroprocessed	Hydrocracking
Parameter	diesel fraction	diesel fraction

Cetane number, un.	46.2	55.7
Lubricity: the corrected parameter of	564	635
the wear scar diameter at 60° C., μm
Fractional formulation:	9.5	1.1
distilled up to 180° C., vol. %
distilled up to 360° C., vol. %	97.4	98.3
Overall sulfur content, mg/kg	<10	5.1

Tables 2, 3, 4-The component formulation of the samples of the proposed diesel fuel composition comprising the synergistic composition of the organic peroxide and the antiwear additive based on carboxylic acids, and results of its testing in comparison with the composition comprising 2-ethylhexyl nitrate.

TABLE 2
	Content of the components, wt. %/number of sample/

Component	1	2	2a	2b	3	3a	4	4a	4b	5
Hydroprocessed	99.97	99.77	99.47	99.5	99.77	99.7	99.77	99.77	99.47	99.77
diesel fraction
Hydrocracking
diesel fraction
Antiwear additive	0.03	0.03	0.03	—	0.03	0.1	0.005	0.03	0.03	0.03
Di-tert-butyl	—	0.2	0.5	0.5	—	—	—	—	—	—
peroxide
1,1-di	—	—	—	—	0.2	0.2	—	—	—	—
(tert-butyl
peroxy)cyclohexane
Dicumyl peroxide	—	—	—	—	—	—	0.01	0.2	0.3	—
2-ethylhexyl nitrate	—	—	—	—	—	—	—	—	—	0.2

Parameter

Parameter value

Lubricity: the	398	356	328	359	359	332	425	348	325	405
corrected parameter
of the wear scar
diameter at
60° C., μm
Cetane number,	46.2	52.0	54.6	54.6	53.3	53.3	51.4	54.8	53.2	53.2
in
Content of adsorption	—	692	765	698	805	867	769	785	803	744
resine, mg per
100 cm2 of the fuel
Overall residue mass,	—	0.300	0.400	0.375	0.675	0.725	0.725	0.700	0.675	0.750
ml/106 ml 2)

									Requirements of
									GOST 32511-
									2013, GOST R

Content of the components, wt. %/number of sample/

52368-2005 and

	Component	6	7	8	8a	8	10	TR CU 013/2011

	Hydroprocessed
	diesel fraction
	Hydrocracking	99.97	99.77	99.77	99.7	99.77	99.77
	diesel fraction
	Antiwear additive	0.03	0.03	0.03	0.1	0.03	0.03
	Di-tert-butyl	—	0.2	—	—	—	—
	peroxide
	1,1-di	—	—	0.2	0.2	—	—
	(tert-butyl
	peroxy)cyclohexane
	Dicumyl peroxide	—	—	—	—	0.2	—
	2-ethylhexyl nitrate	—	—	—	—	—	0.2

Parameter

Parameter value

Lubricity: the

404

438

354

337

380

467

not more than 460

	corrected parameter
	of the wear scar
	diameter at
	60° C., μm

Cetane number,

55.7

64.7

62.2

62.2

63.2

62.2

not less than 51

in

Content of adsorption

—

333

263

328

236

116

not more than 2500 1)

	resine, mg per
	100 cm2 of the fuel

Overall residue mass,

—

0.450

0.550

0.650

0.575

0.625

not more than 2

	ml/106 ml 2)
Note:
1) Determined according to STO 11605031-056, the regulation is established within the MCO (MKO),
2) Determined according to STO 11605031-077-2013, the method is qualified, it is not included into the ND for diesel fuel
indicates data missing or illegible when filed

TABLE 3
	Content of the components, wt. %/number of sample/

Component	1	2	2a	2b	3	3a	4	4a	4b	5
Hydroprocessed	99.97	99.77	99.47	99.5	99.77	99.7	99.77	99.77	99.47	99.77
diesel fraction
Hydrocracking
diesel fraction
Antiwear additive	0.03	0.03	0.03	—	0.03	0.1	0.005	0.03	0.03	0.03
Tert-butyl cumyl	—	0.2	0.5	0.5	—	—	—	—	—	—
peroxide
Isobutyl cumyl	—	—	—	—	0.2	0.2	—	—	—	—
peroxide	—	—	—	—	—	—	0.01	0.2	0.5	—
2-ethylhexyl nitrate	—	—	—	—	—	—	—	—	—	0.2

Parameter

Parameter value

Lubricity: the	398	356	328	559	359	332	425	346	325	405
corrected parameter
of the wear scar
diameter at
60° C., μm
Cetane number,	46.2	52.0	54.6	54.6	53.3	53.3	51.4	54.6	57.2	53.2
in
Content of adsorption	—	692	785	698	805	867	769	785	803	744
resine, mg per
150 cm2 of the fuel
Overall residue mass,	—	0.305	0.400	0.375	0.675	0.725	0.725	0.700	0.675	0.750
ml/106 ml 2)

									Requirements of
									GOST 32511-
									2013, GOST R

Content of the components, wt. %/number of sample/

52368-2005 and

	Component	6	7	8	8a	9	10	TR CU 013/2011

	Hydroprocessed
	diesel fraction

Hydrocracking

99.97

99.77

99.77

99.7

99.77

99.77

	diesel fraction
	Antiwear additive	0.03	0.03	0.03	0.1	0.03	0.03
	Tert-butyl cumyl	—	0.2	—	—	—	—
	peroxide
	Isobutyl cumyl	—	—	0.2	0.2	—	—
	peroxide	—	—	—	—	0.2	—
	2-ethylhexyl nitrate	—	—	—	—	—	0.2

Parameter

Parameter value

Lubricity: the

404

418

354

337

380

467

not more than 460

	corrected parameter
	of the wear scar
	diameter at
	60° C., μm

Cetane number,

55.7

64.7

62.2

62.2

63.2

62.2

not less than 51

in

Content of adsorption

—

133

263

328

236

120

not more than 2500 1)

	resine, mg per
	150 cm2 of the fuel

Overall residue mass,

—

0.450

0.550

0.630

0.575

0.625

not more than 2

	ml/106 ml 2)
Note:
1) Determined according to STO 11605031-056, the regulation is established within the MCO (MKO),
2) Determined according to STO 11605031-077-2013, the method is qualified, it is not included into the ND for diesel fuel
indicates data missing or illegible when filed

TABLE 4
	Content of the components, wt. %/number of sample/

Component	1	1a	2	2a	2b	2c	2d	3	3a	3b	3c
Hydroprocessed	99.97	99.77	99.77	98.87	99.5	99.07	99.77	99.77	99.7	99.4	98.2
diesel fraction
Hydrocracking
diesel fraction
Antiwear additive	0.03	0.03	0.03	0.03	0.03	0.03	0.03	0.03	0.3	0.1	0.3
Isopropyl cumyl	—	0.2	—	—	—	—	—	—	—	—	—
peroxide
Ethyl cumyl	—	—	—	—	—	0.3	0.2	—	—	—	—
peroxide
Methyl cumyl	—	—	—	—	—	—	—	—	—	0.3	0.3
peroxide
2-ethylhexyl	—	—	—	—	—	—	—	—	—	—	—
acetate

Parameter

Parameter value

Lubricity: the	398	372	356	328	328	382	363	350	323	262	354
corrected
parameter
of the wear scar
diameter at
60° C., μm
Cetane number,	46.2	35.5	52.9	34.6	34.6	58.6	35.3	35.3	35.3	33.5	33.1
in
Content of	—	708	602	705	695	732	728	800	867	832	836
adsorption
resine, mg per
150 cm2 of the
fuel
Overall residue	—	0.350	0.300	0.400	0.375	0.425	0.400	0.635	0.720	0.625	0.700
mass, ml/106 ml 2)

										Requirements of
										GOST 32511-

Content of the components, wt. %/number of sample/

2013, GOST R

52368-2005 and

	Component	4	4a	4b	4c	5	9	10	TR CU 013/2011

	Hydroprocessed	98.77	99.77	99.87	99.49	99.77	—	—
	diesel fraction
	Hydrocracking	—	—	—	—	—	99.77	99.77
	diesel fraction
	Antiwear additive	0.005	0.03	0.03	0.03	0.03	0.03	0.03
	Isopropyl cumyl	—	—	—	0.5	—	—	—
	peroxide
	Ethyl cumyl	—	—	—	—	—	—	—
	peroxide
	Methyl cumyl	—	—	—	—	—	—	—
	peroxide
	2-ethylhexyl	—	—	—	—	0.2	—	0.2
	acetate

Parameter

Parameter value

	Lubricity: the	425	336	325	353	405	380	407	not more
	corrected								than 460

	parameter
	of the wear scar
	diameter at
	60° C., μm

Cetane number,

11.4

34.0

57.2

56.3

87.1

63.3

83.2

not less than 51

in

	Content of	749	785	805	792	346	256	110	not more than
	adsorption								2500 1)
	resine, mg per

	150 cm2 of the
	fuel

Overall residue

0.725

0.700

0.675

0.725

0.750

0.525

0.623

not more than 2

	mass, ml/106 ml 2)
Note:
1) Determined according to STO 11605031-056, the regulation is established within the MCO (MKO),
2) Determined according to STO 11605031-077-2013, the method is qualified, it is not included into the ND for diesel fuel
indicates data missing or illegible when filed