RU2455342C1 - Method of obtaining winter diesel oil - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention refers to method of obtaining winter diesel oil from sulphurous desalted crude oil with the use of oil refining, fractionation distillating within 180 to 300-310°C and 180 to 335-345°C, fraction compounding in certain ratio for obtaining 1 class fuel and 2 class fuel. The mixture is hydrotreated with obtainment of hydrogenation product with sulphur content less than 10 ppm, the depressor-dispersant additive "Dodiflow 5416" is added in quantity of 200-250 ppm.

EFFECT: obtaining of winter diesel oil that meets EURO standards requirements.

1 tbl, 8 ex

Description

The invention relates to oil refining, in particular to a method for producing diesel fuel for a cold climate from products of direct distillation of oil. Currently, there is an increasing increase in the demand for diesel fuel intended for use in low ambient temperatures.

With the entry into force of the Technological Regulation of February 28, 2008, “On requirements for automobile and aviation gasoline, diesel and marine fuel, jet fuel and heating oil” and GOST R 52368-2005 (EN-590: 2004) “Diesel fuel EURO. Specifications ", the low-temperature properties of diesel fuels are characterized by a limiting filterability temperature (PTF) - the highest temperature at which the standard filter is clogged with normal paraffins (n-paraffins) of diesel fuel and the cloud point (TP) - the temperature at which the first crystals of normal paraffins. For the cold and arctic climate, diesel fuel in accordance with GOST is divided into classes and has the following PTF and TP indicators:

Class 0 one 2 3 four PTF -twenty -26 -32 -38 -44 TP -10 -16 -22 -28 -34

In this case, the flash point of all grades and classes of diesel fuel should be at least 55 ° C. In addition, in diesel fuel of the third type, the sulfur content should not exceed 10 mg / kg (ppm).

The low temperature properties of diesel fuels (TP and PTF) are determined by the presence of normal paraffins. Straight-chain paraffins form crystals at low temperatures, which is the main reason for clogging filters and fuel lines. There are several ways to improve diesel performance:

- a decrease in the end of boiling of diesel fuels, since most of the paraffins that worsen low-temperature properties are within the boiling range above 300 ° C [Chesnovitsky V.G. Obtaining depressant additives for diesel and heating oils. Chemistry and technology of fuels and oils, 1993, No. 1, p. 7-8]. However, this significantly reduces the fuel yield (up to 20%), there is a decrease in the cetane number of fuel;

- mixing with the kerosene fraction is a traditional way to prevent the deposition of paraffins by dissolving them in the lighter fraction of kerosene. The disadvantages of this method are a decrease in the production of jet fuel, a decrease in the flash point and the cetane number of diesel fuel;

- Zeolite dewaxing of diesel fuel as well as catalytic dewaxing, allows to obtain high quality fuel [Duker A. Use new catalyst technologies to process ultra-low-sulfur diesel., Hydrocarbon Processing. - 2008. - 87. - No. 2. - p. 59-62]. The use of various types of dewaxing to obtain diesel fuel with low temperature properties is described, in particular, by patents of the Russian Federation No. 22219221; 2381259, however, high capital and production costs do not always allow timely organization of fuel production using these processes. In addition, when implementing the solution described in patent No. 2039791, a fuel is obtained with a flash point below 55 ° C and with a sulfur content of up to 0.2% by weight, which does not meet modern requirements. A significant disadvantage of the method described in patent No. 2108370 is the involvement of gasoline and kerosene fractions, which reduces the resources of automobile and jet fuels. The use of depressant-dispersant additives to improve the cold flow of diesel fuels is a quick and easy solution to the problem. When fuel is treated with various additives, the pour point can be significantly reduced, the cetane number is increased, the combustion coefficient is improved, and the smokiness of the exhaust gases is reduced. However, the effect of depressant-dispersing additives in diesel fuels is not always effective, and when the quality of the initial fuel changes, their use does not always allow for stable production of fuels with the required PTF values. In the production of diesel fuel with a depressant-dispersant additive based on diesel fuels of different fractional composition and different nature, it is necessary to take into account the individual characteristics of diesel fuels, in particular the molecular mass distribution of paraffins, which is an important indicator that can "explain" the behavior of a depressant additive without taking into account the variety of other factors [V.I. Yakunin, V.A. Krylov, L.V. Abramova, V.A. Otrokov. Features of the production of modern diesel fuels at the company LLC “LUKOIL-Permnefteorgsintez” Oil refining and petrochemicals. - 2008. - No. 8, p. 17-22].

A known method of producing winter diesel fuel (RF patent 2126437), in which oil is distilled with the allocation of kerosene fraction (120-240) -270 ° C and diesel fractions (140-300) -330 ° C and 210- (350-370) ° C, gasoline is distilled to separate the residual fraction 170-270 ° C, the separated vacuum gas oil is subjected to catalytic cracking to obtain light gas oil, followed by mixing it with diesel fractions in a certain mass ratio, further hydrotreating and compounding the fractions and depressant additive.

The disadvantage of this method is the need to isolate the residual fraction from gasoline, the use of kerosene fractions, which reduces the production of automotive and jet fuels, the use of light catalytic gas oil, even after mild hydrotreating, increases the content of polycyclic hydrocarbons in diesel fuel.

The purpose of the method described in RF patent 2141505 is to increase the yield of winter diesel fuel through the use of fuel of a heavier fractional composition, in which atmospheric-vacuum distillation of oil, compounding of fractions and hydrotreating of distillates is carried out. At atmospheric distillation of oil receive: fraction, 98% of which boils in the range 160-330 ° C; fraction, 96% in the range of 260-370 ° C, the residual fraction above 360 ° C is subjected to vacuum distillation with separation of the fraction, 96% of which boils at 220-370 ° C; 10-30% of the fraction 260-370 ° C is subjected to secondary distillation with the separation of fractions 220-330 ° C and 320-370 ° C. Compounds are framed in certain proportions and hydrotreated, then again compounding and the introduction of a depressant additive. The disadvantage of this method is the inability to obtain fuel with a sulfur content of less than 10 ppm.

In the technical solution according to the patent of the Russian Federation 2039080, distillation of oil is used to obtain winter diesel fuel from sulphurous oils to obtain fractions, 96% of which are boiled away respectively within 140- (280-310) ° C and 210- (240-350) ° C. A mixture of these fractions (mass ratio from 10:90 to 35:65) is subjected to hydrotreating. The obtained fraction, 96% of which boils in the range of 210- (340-350) ° C, taken in a mass ratio of 10:90 to 90:10, respectively, is combined with 30-50 wt.% Of the fraction, 96% of which boils in the range of 140 - (280-310) ° C. A depressant additive in an amount of 0.01-0.5 wt.% Is introduced into the obtained base fuel. The disadvantage of this method is the inability to obtain fuel with a sulfur content of less than 10 ppm.

The closest in technical essence to the proposed one is a method for producing winter diesel fuel, in accordance with RF patent No. 2237701, which uses oil distillation, hydrotreating, compounding fractions, the introduction of a depressant additive - a copolymer of ethylene with vinyl acetate, while fractions are isolated during oil distillation, 96% of which boils within 140- (280-290) ° С and 305- (390-405) ° С. The fraction 140- (280-290) ° C is subjected to hydrotreating and mixed with the fraction 305- (390-405) ° C in a weight ratio of 75:25 to 95: 5. A depressant is added to the resulting base fuel. The disadvantage of this method is the mismatch of the fuel obtained in sulfur content (above 10 ppm) with the requirements of GOST R 52368-2005 (EH 590: 2004).

The aim of the creation of the present invention is to develop a method for producing winter diesel fuel using straight-run fractions that meets the requirements of the Technological Regulation of 02.28.2008 "On requirements for automobile and aviation gasoline, diesel and marine fuel, jet engine fuel and heating oil" and GOST P 52368-2005 (EN-590: 2004) “Diesel fuel EURO”.

The goal is solved by the implementation of a method for producing winter diesel fuel, in accordance with which desalted oil is subjected to distillation at ABT units, fractions are boiled away within 180- (300-310) ° С (АВТ 1) and 180- (335-345) ° C (ABT 2). The obtained fractions are mixed to obtain class 1 fuels in the ratio of 40-60: 60-40, to obtain class 2 fuels in the ratio of 80-85: 20-15. The resulting mixture is sent to hydrotreating to obtain a hydrogenate with a sulfur content of less than 10 ppm, to which a depressant-dispersing additive is added in an amount of 200-250 ppm. The additive used in the implementation of the invention may be a depressant-dispersant additive, for example, "Dodiflow 5416" from Clariant. The dosage of the additive depends on the characteristics of the processed fuel; for the proposed solution, the indicated one is optimal.

Various depressant-dispersant additives are presented on the Russian market to improve the low-temperature properties of diesel fuels. Upon receipt of winter fuels, the applicant studied the performance of some depressant-dispersant additives of various companies, such as Keroflux3665 (BASF); HiTEC 4576+ HiTEC 4578 (Afton), Dodiflow-5416 (Clariant). Any of the above grades can be used to lower the maximum temperature of filterability of diesel fuel. However, during testing, the additive Dodiflow-5416 (Clariant) proved to be most effective both in achieving the required standards of ND and in the lowest dosage. That is why the applicant conducted research on the production of winter diesel fuel based on this additive. It is possible that when obtaining winter fuels at other enterprises, the above or any other depressant-dispersing additives may be used, however, for this it is necessary to select the optimal dose to achieve the desired effect. The applicant has conducted studies regarding the additive "Dodiflow 5416".

The hydrotreating process to produce diesel fuel with a sulfur content of less than 10 ppm was developed at LUKOIL-Nizhegorodnefteorgsintez LLC (see patent No. 2387700) and is applied taking into account its features.

The catalyst is aluminum-cobalt-molybdenum or aluminum-nickel-molybdenum

Pressure, kg / cm ² 20-60 Temperature ° C 340-400 Volumetric feed rate, h ^-1 1-3 The multiplicity of the circulation of hydrogen-containing gas, nm ³ / m ³ 200-600 The hydrogen content in the circulating gas,% vol. 75-95

The fraction selected after hydrotreating, boiling within 180-330 ° С, meets the requirements of GOST and the "Technical Regulations", the indicator "limiting filterability temperature" is corrected by adding an additive.

The proposed method allows to obtain winter diesel fuel that meets the requirements of regulatory documents, with minimal use of jet fuel components and does not increase existing operating costs.

The presence of a fraction boiling in the range from 180 to 300-310 ° C provides the required cloud point in the mixture, for fuel of the first class at least -16 ° C and for fuel of the second class at least -22 ° C.

The presence of a fraction boiling in the range from 180 to 335-345 ° C ensures the optimization of the fractional composition of mixed diesel fuel to prevent sharp mass precipitation of n-paraffin crystals due to the introduction of a small amount of n-paraffins crystallizing below the cloud point contained in the diesel fuel fraction with KK 335-345 ° C. When the fuel is cooled below the cloud point, their crystallization is gradual and the formation of large agglomerates of paraffin crystals is prevented due to interaction with the additive.

Examples illustrating the method proposed as an invention are shown in Table 1. The production of class 1 diesel fuel is shown in Examples 1-5.

Fuel with quality indicators that meet the requirements of GOST R 52368-2005 and the “Technological Schedule” of February 28, 2008, class 1 (examples 1; 3; 4), is obtained in accordance with the proposed method when mixing fractions boiling within 180- ( 300-310) ° С (АВТ 1) and 180- (335-345) ° С (АВТ 2) in the ratios 40-60: 60-40. After compounding in the indicated ratios, the fractions were sent for hydrotreating. After hydrotreating, a fuel with a sulfur content of not more than 10 ppm was obtained. To achieve the required maximum filterability temperature, a depressant-dispersing additive was introduced at a concentration of 200 ppm. A concentration of 150 ppm does not provide the desired PTF value; using an additive at a concentration of 250 ppm is not economically viable, since the desired result is achieved with an additive concentration of 200 ppm (Example 1).

It should be noted that these examples illustrate the production of winter diesel fuel that meets the requirements of GOST and the "Technological Schedule" and for other indicators. The resulting fuel belongs to class 1, type 3, since its sulfur content is less than 10 ppm.

The use of a component with a low boiling point (Example 2) 180-326 ° C does not provide a low crystallization rate of paraffins, both without an additive, and does not prevent the agglomeration of crystals when interacting with it.

The use of a “weighted” component with a boiling end of 350 ° С (example 5) does not allow “reaching” the regulated temperature level of cloud point ТП - 15 ° С.

Class 2 diesel fuel production is illustrated in Examples 6-8.

Fuel with quality indicators that meet the requirements of regulatory documents, class 2 (examples 6; 7), is obtained in accordance with the proposed method by mixing fractions with ABT 1 and ABT 2, boiling in the range of 180- (300-310) ° С and 180- (335-345) ° С in the proportions (80-85) :( 20-15), further hydrotreating the mixture to obtain a fuel with a sulfur content of less than 10 ppm and adding a Clariant Dodiflow 5416 depressant-dispersant additive at a concentration of 250 ppm .

An additive concentration of 150 ppm does not provide the desired PTF value, an additive concentration of 500 ppm is not economically advantageous, since the desired result is achieved with an additive concentration of 250 ppm (Example 6).

The fuel belongs to class 2, type 3, since the sulfur content in it is less than 10 ppm and meets the requirements of GOST and the "Technological Schedule" and other indicators.

The use of components in the ratio of 75:25 (example 8) does not provide the required cloud point, the fuel does not correspond to class 2. The quality indicators of the obtained fuel correspond to the indicators of class 1, however, obtaining fuel of class 1 with such ratios of fractions is not economically profitable.

The use of fractions with a boiling point of less than 180 ° C is not desirable, since the volume of production of jet fuel is reduced.

A decrease in the end of boiling of the “heavy” fraction below 335 ° C leads to an increase in PTF due to the lack of the required amount of heavy paraffins for the normal operation of the additive.

Raising the boiling end of the “lightweight” fraction above 310 ° C is not advisable, since it does not provide a cloud point corresponding to the requirements of GOST.

Proposed as an invention, a method of producing diesel fuel is used at LUKOIL-Nizhegorodnefteorgsintez LLC and provides fuel that complies with EURO standards.

Claims (1)

A method of producing winter diesel fuel from desalted sulfur oils using oil distillation, compounding fractions, hydrotreating, introducing a depressant-dispersing additive into the hydrogenate, characterized in that fractions boiling over from 180 to 300-310 ° C and from 180 to 335-345 ° C, they are compounding in the ratios: to obtain fuel of class 1 - 40-60: 60-40; for producing a fuel grade 2 - 80-85: 20-15, and the mixture is subjected to hydrorefining to obtain hydrogenation with a sulfur content of less than 10 million ^1, to which is added depressant-dispersant additive «Dodiflow 5416» in an amount of 200-250 mn ^-1.