RU2311442C1 - Method of production of the sweet oil middle-distillate fractions having the improved low-temperature characteristics - Google Patents

Abstract

FIELD: petrochemical industry; other industries; methods of production of the sweet oil middle-distillate fractions with the improved low-temperature characteristics.

SUBSTANCE: the invention is pertaining to the method of production of the sweet oil middle-distillate fractions with the improved low-temperature characteristics by their treatment in the hydrogen medium at the increased pressure and temperature in the presence of the catalysts or the catalytic systems characterized by the fact, that the fractions with the temperature of the boiling end of 210-280°C are treated with the catalysts or the catalytic systems intended predominantly for transformation of the hetero-organic compounds; the fractions with the temperature of the boiling point of 210-280°C are treated with the catalytic systems consisting of the catalysts of transformation of the hetero-organic compounds and the n-paraffinic hydrocarbons; at that the catalysts of the preferable transformation of the hetero-organic compounds represent the alumonickel(cobalt) molybdenum oxide catalysts; the catalytic systems of the preferential transformation of the hetero-organic compounds represent the catalytic systems consisting of the indicated catalysts, and the catalysts of transformation of the n-paraffin hydrocarbons contain the alumosilicate compounds of the crystalline structure in the form of zeolites of the pentasil type and the active hydrogenating components in the form of the nickel oxide or the mixture of nickel oxides and molybdenum.

EFFECT: the invention ensures production of the sweet oil middle-distillate fractions with the improved low-temperature characteristics.

3 cl, 8 tbl, 17 ex

Description

The invention relates to oil refining, in particular, to methods for producing low-sulfur middle distillate fractions with improved low-temperature properties.

Obtaining medium distillate fuels with a given residual sulfur content is achieved by the use of hydrocatalytic processes based on the conversion of organosulfur compounds contained in raw materials. These processes are carried out in a hydrogen environment at elevated temperature and pressure using alumina-nickel and / or alumina-cobalt-molybdenum catalysts [RF Patents No. 2103065, 2271861, 2245896].

Correction of low-temperature characteristics of distillate fuels is achieved:

- the use of depressant additives,

- a decrease in the concentration in the fuel of hydrocarbons with high melting points.

The most representative group with high melting points in the middle distillate fractions are n-paraffin hydrocarbons with a high molecular weight [Gureev A.A., Azev B.C., Kamfer G.M. Fuel for diesel engines. Properties and applications. M .: Chemistry, 1993, p. 22-32].

You can reduce the content of high molecular weight n-paraffin hydrocarbons in the resulting product by:

- their physical separation from the fuel composition (urea dewaxing, adsorption on molecular sieves, freezing, lowering the temperature of the end of boiling of the product),

- dilution with lighter fractions, for example kerosene,

- the chemical conversion of n-paraffins with a high molecular weight to iso-paraffins or n-paraffins with a lower molecular weight.

The preparation of low-hardening middle distillate fractions by means of carbamide dewaxing has lost its significance due to the low processability of the method.

A known method of dewaxing diesel fuel obtained from gas condensate, comprising cooling diesel fuel to a temperature at which high-melting paraffins become solid, separating the resulting mixture in a precipitation centrifuge, followed by filtration on a vacuum filter with the release of low-setting diesel fuel and a mixture of n-paraffin hydrocarbons [Application for invention No. 2003104779].

The disadvantages of this method include the low yield of fuel fractions and limited use in large-scale production.

Limiting the temperature of the boiling point of the diesel fraction to 300-320 ° C or involving gasoline and kerosene fractions in the composition of diesel fuel leads to a decrease in the production of either diesel fuels or gasolines and aviation kerosene.

Known methods for producing winter diesel fuel by distillation of oil to obtain narrow fractions, hydrotreating some of them or their compounds, compiled in a predetermined ratio, followed by the introduction of a depressant additive in the resulting product [RF Patents No. 2039080, 2237701].

The disadvantage of these methods is the complex technological scheme and the need to use depressant additives, which allows to lower the pour point of medium distillate fuel, but does not affect the temperature of its cloudiness and crystallization [Gulyaeva LA, Khavkin VA, Kaminsky E.F. and others // Oil refining and petrochemistry, 1999, No. 6, p.18-23].

A known method of producing winter diesel fuel by distillation of oil with the separation of kerosene and diesel fractions, mixing of diesel fractions, directing the resulting mixture to secondary distillation with separation of the fraction 200-320 ° C, catalytic hydrotreating and subsequent dewaxing of the fraction 200-320 ° C by adsorption of n- paraffins on zeolites, mixing the dewaxed and hydrotreated fractions of 200-320 ° C with a mixture of diesel fractions and subjected to additional catalytic hydrotreating with a kerosene fraction [RF Patent No. 2039791]. This method is characterized by a multi-stage chain of fractionation and mixing of oil fractions, which is associated with the complexity of the hardware design of the process and significant losses of the product. The allocation of n-paraffin hydrocarbons by adsorption on zeolites also leads to a decrease in the yield of fuel fractions.

The most rational way to improve the low-temperature characteristics of middle distillate fractions is the use of hydrogenation processes aimed at carrying out reactions of the conversion of n-paraffin hydrocarbons into iso-paraffins and n-paraffins with a lower molecular weight [Smirnov VK, Irisova KN, Talisman E. L. and others // Chemistry and technology of fuels and oils, 2004, No. 4, p. 37-41].

Such processes are carried out at certain technological parameters using special catalysts.

Known methods for producing low-solidifying petroleum products by catalytic dewaxing of hydrocarbon distillates on catalysts containing high silica zeolites, binders and hydrogenating components, additives that increase activity, selectivity, and catalyst strength [RF Patents No. 2109792, 2141503, EP No. 2235115].

The disadvantage of these methods is their relatively low productivity due to the insufficient activity of the used catalysts.

The use of technical solutions set forth in Russian patents No. 2183505 and No. 2225433 allows you to remove the above disadvantages of zeolite-containing catalysts when used in hydrogenation processes, but does not provide low-sulfur middle distillate fractions.

The closest in technical essence and the achieved effect is a method for producing low-sulfur oil fractions in a hydrogen medium at elevated pressure and temperature using catalytic systems consisting of catalysts having the functions of changing the hydrocarbon composition and purification from organoelement compounds [RF Patent No. 2245896].

The hydrotreating of middle distillate fractions in accordance with the conditions specified by the formula of this patent is accompanied by a high yield of gases and liquid hydrocarbons boiling off at temperatures up to 180 ° C, which leads to a decrease in the yield of the target product.

The aim of the proposed technical solution is to obtain under the conditions of existing hydrotreatment plants low-sulfur middle distillate fractions with desired low-temperature characteristics without reducing the yield of the target product.

The production of low-sulfur medium-distillate fuels with improved low-temperature properties is possible using hydrocatalytic processes aimed at transforming organoelement compounds and n-paraffin hydrocarbons under the conditions of the most efficient course of each of the processes.

This goal is achieved by the method of producing low-sulfur middle distillate fractions with improved low-temperature characteristics by processing them in a hydrogen medium at elevated pressure and temperature in the presence of catalysts or catalytic systems, provided that fractions with a boiling point of 210-280 ° C are processed on catalysts or catalytic systems intended primarily for the conversion of organoelement compounds; fractions with a boiling point of 210-280 ° C are processed on catalytic systems consisting of catalysts for the conversion of organoelement compounds and n-paraffin hydrocarbons; while the catalysts for the predominant conversion of organoelement compounds are alumino-nickel (cobalt) molybdenum oxide catalysts; the catalytic systems for the preferential conversion of organoelement compounds are catalytic systems consisting of these catalysts, and the catalysts for the conversion of n-paraffin hydrocarbons contain crystalline aluminosilicate compounds in the form of pentasil type zeolites and active hydrogenation components in the form of nickel oxide or a mixture of nickel and molybdenum oxides; fractions with a boiling point of 210 ÷ 280 ° C are processed at a pressure of 30-70 ati, a temperature of 320-380 ° C, a volumetric feed rate of 2.0-4.0 hour ^-1 , fractions with a boiling point of 210 ÷ 280 ° C processed on catalytic systems, which include catalysts for the conversion of organoelement compounds and n-paraffin hydrocarbons, taken in the ratio (0.8-1.0) ÷ (1.0-1.2) at a pressure of 30-70 atm, temperature 320 -380 ° C, the volumetric feed rate of 0.6-1.2 hours ^-1 .

A distinctive feature of the invention is that fractions with a boiling point of 210-280 ° C are treated on catalysts or catalytic systems designed primarily for the conversion of organoelement compounds; fractions with a boiling point of 210-280 ° C are processed on catalytic systems consisting of catalysts for the conversion of organoelement compounds and n-paraffin hydrocarbons; while the catalysts for the predominant conversion of organoelement compounds are aluminonickel (cobalt) molybdenum catalysts; the catalytic systems for the preferential conversion of organoelement compounds are catalytic systems consisting of these catalysts, and the catalysts for the conversion of n-paraffin hydrocarbons contain crystalline aluminosilicate compounds in the form of pentasil type zeolites and active hydrogenation components in the form of nickel oxide or a mixture of nickel and molybdenum oxides; fractions with a boiling point of 210 ÷ 280 ° C are processed at a pressure of 30-70 ati, a temperature of 320-380 ° C, a volumetric feed rate of 2.0-4.0 hour ^-1 , fractions with a boiling point of 210 ÷ 280 ° C processed on catalytic systems, which include catalysts for the conversion of organoelement compounds and n-paraffin hydrocarbons, taken in the ratio (0.8-1.0) ÷ (1.0-1.2) at a pressure of 30-70 atm, temperature 320 -380 ° C, the volumetric feed rate of 0.6-1.2 hours ^-1 .

The proposed method for producing low-sulfur middle distillate fractions with improved low-temperature characteristics is as follows.

A wide middle distillate fraction is divided into fractions with a boiling point of 210-280 ° C and a boiling point of 210-280 ° C, respectively.

A fraction with a boiling point of 210-280 ° C is processed on catalysts or catalytic systems designed primarily for the conversion of organoelement compounds, which are alumina-nickel (cobalt) molybdenum oxide systems, at a pressure of 30-70 atm, a temperature of 320-380 ° C, and space velocity feedstock 2.0-4.0 hour ^-1 .

A fraction with a boiling point of 210 ÷ 280 ° C is processed on catalytic systems, which include catalysts for the conversion of organoelement compounds and n-paraffin hydrocarbons, taken in the ratio (0.8-1.0) ÷ (1.0-1.2 ) at a pressure of 30-70 ati, a temperature of 320-380 ÷ C, a volumetric feed rate of 0.6-1.2 hours ^-1 .

The catalysts for the conversion of n-paraffin hydrocarbons contain crystalline aluminosilicate compounds in the form of pentasil type zeolites and active hydrogenating components in the form of nickel oxides or a mixture of nickel and molybdenum oxides.

Products obtained by processing fractions with a boiling point of 210 ÷ 280 ° C and a boiling point of 210 ÷ 280 ° C are compounding.

The preliminary separation of the middle distillate fraction into fractions with a boiling point of 210–280 ° С and a boiling point of 210–280 ° С allows directing a fraction enriched in high molecular weight n-paraffin hydrocarbons to a zeolite-containing catalyst designed to convert n-paraffin hydrocarbons correspondingly high melting points, the conversion of which into iso-paraffins and n-paraffins with a lower molecular weight leads to an improvement in the low-temperature parameters of the resulting product. The use of catalysts in the composition of the catalytic system for the predominant conversion of organoelement compounds allows us to obtain a product not only with low cloud point and solidification temperature, but also with a low sulfur content.

Separate processing of the low-temperature fraction enriched with n-paraffin hydrocarbons with a relatively low molecular weight and low temperature parameters that meet the requirements for winter diesel fuels allows the desulfurization process to be carried out under the most effective conditions, which generally leads to the production of low-sulfur medium distillate fractions with improved low-temperature indicators.

In addition, this reduces the formation of gaseous hydrocarbons, which leads to an increase in the yield of the target fraction.

In the known methods, the production of low-sulfur middle distillate fractions with improved low-temperature characteristics using the described technology is unknown.

Thus, this technical solution meets the criteria of "novelty" and "significant difference".

Examples.

When testing the proposed technical solution, the catalysts used were samples obtained in accordance with the method of producing catalysts according to the materials of Russian patents No. 2183505 (catalyst for the conversion of n-paraffin hydrocarbons) and No. 2103065 (catalysts for the predominant conversion of organoelement compounds), see Table 1.

Table 1.
The list and characteristics of samples of catalysts used in the implementation of the invention. Catalyst sample Content, wt.% MoO ₃ CoO / NiO pentasil Al ₂ About ₃ Heteroorganic Conversion Catalysts one 14.1 4,5 / 0 0 Ost. 2 12,2 0 / 3.9 0 Ost. The catalyst for the conversion of n-paraffin hydrocarbons 3 8.0 0 / 2.0 40,0 Ost. four 0 0 / 2.0 40,0 Ost.

As a raw material, a straight-run middle distillate fraction was used, the characteristics of which are given in Table 2.

Table 2.
Characteristics of a sample of raw materials used in the implementation of the invention. Indicators Value Density at 20 ° С, kg / m ³ 837.0 Fractional composition, ° C: - start of boiling 178 - 10% distilled 192 - 50% distilled at 272 - 90% distilled at 338 - end of boiling 362 Iodine value, g I _2/100 g 1.27 Cloud point, ° С -5 Pour point, ° C -eleven The total sulfur content, wt.% 0.91

The low temperature characteristics of diesel fuels according to GOST 305-82 are given in table 3.

Table 3. Low temperature characteristics of diesel fuels according to GOST 305-82 Indicators Brand Standards Summer Winter Arctic Cloud point, ° С -5 -25 - Pour point, ° C -10 -35 -55

It can be seen that the low-temperature characteristics of the straight-run fraction (Table 2) do not meet the requirements for commercial diesel fuels, and require adjustment.

The characteristics of the narrow fractions isolated from the raw material sample used in the tests are given in Table 4.

Table 4. Characterization of fractions isolated from the raw material sample used in testing Acceleration No. Faction No. Boiling range, ° С Yield, vol.% Temperature ° C Sulfur content, wt.% turbidity solidification one eleven 178 ÷ 210 twenty -39 -44 0.41 12 210 ÷ 362 80 -9 -fourteen 1,04 2 21 178 ÷ 280 57 -22 -27 0.61 22 280 ÷ 362 43 -one -7 1.18 3 31 178 ÷ 300 70 -eighteen -22 0.74 32 300 ÷ 362 thirty +1 -3 1.43 four 41 178 ÷ 320 82 -eleven -16 0.82 42 320 ÷ 362 eighteen +5 0 1.73

Fractions nos. 11, 21, 31, 41 (series 1) were processed on catalysts or catalytic systems designed primarily for the conversion of organoelement compounds (samples No. 1 and No. 2 of Table 1), at a pressure of 30-70 atm, temperature 320-380 ° C, the volumetric feed rate of 2.0-4.0 hour ^-1 (examples 1, 3, 5, 7, 9, 11, 13, 15). The conditions and results of the processing of the above examples are given in tables 5 and 7, respectively.

Fractions nos. 12, 22, 32, 42 (series 2) were processed on catalytic systems consisting of catalysts for the conversion of organoelement compounds and n-paraffin hydrocarbons (samples 1, 2, 3, and 4 of Table 1), at a pressure of 30-70 at a temperature of 320-380 ° C, the volumetric feed rate of 0.6-1.2 hour ^-1 (examples 2, 4, 6, 8, 10, 12, 14, 16). The processing conditions and results for the above examples are given in tables 6 and 7, respectively.

Example 17 reflects the process of obtaining low-sulfur middle distillate fractions under the conditions of the prototype. The conditions and results of hydrofining the middle distillate fraction of this example are shown in Tables 6 and 7, respectively.

Table 5.
Processing conditions for fractions of series 1. Example Fraction The composition of the catalytic system, wt.% Technological parameters Arr. No. 1 Arr. Number 2 P, ati T, ° C V, hour ^-1 Example 1 eleven 0 one hundred 70 360 4.0 Example 3 21 one hundred 0 thirty 320 2.0 Example 5 31 one hundred 0 thirty 320 2.0 Example 7 41 one hundred 0 thirty 380 3.0 Example 9 21 fifty fifty 40 340 4.0 Example 11 21 one hundred - 28 310 2.0 Example 13 21 - one hundred thirty 340 5,0 Example 15 21 fifty fifty 80 390 5,0 Table 6.
Processing conditions for feedstock and fractions of series 2. Example Fraction The composition of the catalytic system, wt.% Technological parameters Arr.
No. 1 Arr.
Number 2 Arr.
Number 3 Arr.
Number 4 R,
ati T, ° C V, hour ^-1 Example 2 12 0 40 0 60 70 320 0.6 Example 4 22 fifty 0 fifty 0 thirty 380 1,2 Example 6 32 0 fifty fifty 0 thirty 340 1,2 Example 8 42 fifty 0 fifty 0 thirty 340 1,2 Example 10 22 25 25 0 fifty 40 340 1,0 Example 12 22 thirty 0 70 0 40 340 1,0 Example 14 22 40 0 60 0 40 340 1,5 Example 16 22 25 25 fifty 0 28 310 0.5 Example 17 Feedstock 25 25 0 fifty 40 340 1,5 (prototype)

The quality control of the products obtained during the implementation of the proposed method according to examples 1-16 and prototype (example 17) was carried out according to the following indicators: residual sulfur content, cloud point, pour point, liquid hydrocarbon yield (see table 7).

Table 7.
The quality of the products obtained during the implementation of the proposed method according to examples 1-17. Example Sulfur content, wt.% Temperature ° C The yield of liquid hydrocarbons, wt.% turbidity solidification Example 1 0.004 -37 -42 98 Example 3 0.005 -21 -26 98 Example 5 0.006 -fourteen -twenty 98 Example 7 0.003 -10 -fifteen 98 Example 9 0.001 -21 -26 98 Example 11 0,050 -twenty -25 98 Example 13 0,035 -21 -26 98 Example 15 0,035 -21 -26 98 Example 2 0,035 -53 -60 90 Example 4 0,050 -40 -45 92 Example 6 0,080 -5 -10 95 Example 8 0,080 0 -6 97 Example 10 0,030 -54 -60 92 Example 12 0.010 -5 -10 97 Example 14 0,080 -5 -10 88 Example 16 0,200 -3 -8 98 Example 17 (prototype) 0,035 -fifteen -21 80

It can be seen that the examples made in accordance with the formula of the invention (examples 1, 3, 9 in tables 5 and 2, 4, 10 in table 6) exceed the test results conducted with violations of the conditions laid down in the formula of the invention ( examples 5, 7, 11, 13, 15 in table 5 and 6, 8, 12, 14 in table 6).

In particular, processing on a catalytic system, which includes a catalyst for the conversion of n-paraffins, of a wide fraction (Example 17) leads to a low yield of the target fraction, which reduces the efficiency of the process. The resulting product meets the requirements of only summer diesel fuels. Processing fractions on this catalytic system with a boiling point above 280 ° C results in a product that does not correspond to the pour point and cloud point of commercial diesel fuels (examples 6, 8).

The products obtained in examples 1-16, were compounding. In the compounds, the residual sulfur content, cloud point, and solidification point were determined.

The composition and quality of the resulting compounds are given in table.8.

Table 8.
The composition and quality of the resulting compounds. No. Composition of the compound (products of the examples) Sulfur content, wt.% Temperature ° C Pomut. Freezing one 1 + 2 0,030 -fifty -56 2 3 + 4 0,035 -35 -40 3 5 + 6 0,040 -6 -12 four 7 + 8 0,035 -5 -10 5 9 + 10 0,026 -43 -48 6 11 + 12 0,020 -6 -12 7 13 + 14 0,042 -6 -12 8 15 + 16 0,080 -5 -10 Example 17 0,045 -fifteen -21

It can be seen that the requirements for winter diesel fuels are met by compounds numbered 1, 2, 5, i.e. obtained in accordance with the claims of the invention. The residual sulfur content in these products complies with European standards, i.e. does not exceed 0.035 wt.%.

The product obtained according to the conditions of the prototype, in its low temperature characteristics, can only be used as summer diesel fuel.

Claims (3)

1. A method of producing low-sulfur middle distillate fractions with improved low-temperature characteristics by processing them in a hydrogen medium at elevated pressure and temperature in the presence of catalysts or catalytic systems, characterized in that the fractions with a boiling point of 210-280 ° C are processed on catalysts or catalytic systems, designed primarily for the conversion of organoelement compounds, fractions with a boiling point of 210-280 ° C are processed on catalytic systems, consisting of catalysts for the conversion of organoelement compounds and n-paraffin hydrocarbons, while the catalysts for the predominant conversion of organoelement compounds are aluminum nickel (cobalt) molybdenum oxide catalysts, the catalytic systems for the predominant conversion of organoelement compounds are catalytic systems consisting of these catalysts, and the catalysts for the conversion of n- paraffin hydrocarbons contain aluminosilicate crystal compounds structure in the form of pentasil-type zeolites and active hydrogenating components in the form of nickel oxide or a mixture of nickel and molybdenum oxides. 2. A method according to claim 1, characterized in that the fraction having a final boiling point 210-280 ° C is treated under a pressure of 30-70 atm, a temperature of 320-380 ° C, feed space velocity of 2.0-4.0 h ^{- 1} . 3. The method according to claim 1, characterized in that the fractions with a boiling point of 210-280 ° C are processed on catalytic systems, which include catalysts for the conversion of organoelement compounds and n-paraffin hydrocarbons, taken in the ratio (0.8-1 , 0) ÷ (1.0-1.2) at a pressure of 30-70 ati, a temperature of 320-380 ° C, a volumetric feed rate of 0.6-1.2 h ^-1 .