RU2394804C2 - Method of isomerising light petrol fractions with catalyst preactivation - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to isomerisation of light petrol fractions in order to obtain a high-octane petrol component and can be used in oil-processing and petrochemical industry. The invention particulary relates to a method of isomerising petrol fractions with catalyst preactivation at high temperature and pressure through catalyst activation using a dry inert gas containing 0.1-3.0 vol % oxygen at pressure of 0.5-2.5 MPa while heating at a rate of 10°C per hour to maximum temperature of 450-520°C, where after every 50°C, this temperature is maintained for 3-24 hours, subsequent lowering of the temperature in a stream of inert gas without oxygen, replacement of the inert gas with hydrogen and subsequently bringing the material into contact with a catalyst in a stream of hydrogen.

EFFECT: higher octane number of the isomerisation product.

5 cl, 17 ex, 2 tbl

Description

The invention relates to the field of oil refining and petrochemistry, specifically to isomerization processes of light gasoline fractions in the presence of an activated oxide catalyst, and is intended to produce a high-octane gasoline component.

It is known that for activation of oxide isomerization catalysts, treatment in air is used followed by reduction with hydrogen.

For example, a method for isomerization on a solid acid catalyst is known (US patent No. 7041866, C10G 11/02, 2002), in which the catalyst is activated with air at a temperature of 450 ° C for 2-6 hours and reduced in hydrogen at a temperature of 200 ° C in within 0.5-2 hours.

The disadvantage of this method is the low octane number of the resulting component of motor fuel (isomerizate) due to the low activity of the catalyst (for example, when isomerizing a light gasoline fraction n.c. - 70 ° C at a temperature of 150 ° C, a pressure of 2.8 MPa, the octane number of the isomerizate equal to 80.3 points according to the research method (IOI)).

The known method of isomerization on a solid acid catalyst (US patent No. 5494571, C10G 35/095, 1994), in which the catalyst is activated with air at a temperature of 450 ° C for 12 hours, cooled with nitrogen to 150 ° C and restored in a stream of hydrogen at room temperature temperature for 2 hours.

The disadvantage of this method is the low octane number of the obtained isomerizate due to the low activity of the catalyst (for example, when isomerizing a light gasoline fraction of NK - 70 ° C at a temperature of 150 ° C, a pressure of 2.8 MPa, the octane number of the IOI is 82.2 )

The purpose of the invention is to increase the octane number of the resulting isomerizate while maintaining a high yield.

To achieve this goal, isomerization of light gasoline fractions is carried out at elevated temperature and pressure by activating the catalyst with a dry inert gas containing 0.1-3.0 vol.% Oxygen, at a pressure of 0.5-2.5 MPa, when heated at a speed of 10 ° C per hour to a maximum temperature of 450-520 ° C with holding for 3-24 hours every 50 ° C, starting from 150 ° C, cooling the catalyst in a stream of dry inert gas without oxygen to a temperature of 100-120 ° C, replacing an inert gas with hydrogen, followed by contact of the feed with the catalyst in a stream of hydrogen.

As an inert gas, nitrogen or argon is used.

The process is carried out at a temperature of 100-220 ° C, a pressure of 1.0-3.5 MPa, a molar ratio of hydrogen: feed (0.3-10): 1 on the catalyst composition, wt.%:

Group 8A metal 0.1-0.8 sulfuric acid ion 4-15 metal oxide composition up to 100

As the metal of group 8A, platinum and / or palladium and / or iridium and / or rhodium and / or ruthenium are used, and the composition of metal oxides is:

xFe ₂ O ₃ · yMnO ₂ · zTiO ₂ · nAl ₂ O ₃ · mZrP ₂

at molar values of the coefficients:

x = (0.06-3.6) · 10 ^-3

y = (0.11-2.3) · 10 ^-3

z = (0.12-2.5) · 10 ^-3

n = (7.8-21.5) 10 ^-2

m = (63.3-74.7) · 10 ^-2 .

Distinctive features of the method are the treatment of the catalyst with a nitrogen-oxygen mixture, the oxygen content in this mixture and the processing conditions.

The proposed catalyst treatment provides the formation of active sites and a high activity of the catalyst in the isomerization reaction. In addition, this treatment preserves the strength of the catalyst and removes adsorption water in the catalyst.

The isomerization process described above guarantees the production of a high octane isomerizate.

The isomerization method is as follows.

The catalyst is loaded into the reactor, a dry inert gas with 0.1-3.0 vol.% Oxygen is supplied. The content of impurities in an inert gas should be no more, ppm rev .:

carbon monoxide 1,0 ammonia 1,0 hydrogen sulfide 1,0 carbon dioxide 10.0 water 5,0 hydrogen 2.0 hydrocarbons 3.0

Activation is carried out at a pressure of 0.5-2.5MPa. The temperature rise is carried out at a speed of 10 ° C per hour. The maximum heating temperature is 450-520 ° C. Starting at a temperature of 150 ° C, carry out exposure every 50 ° C for 3-24 hours. Then, the catalyst is cooled with a dry inert gas not containing oxygen to a temperature of 100-120 ° C, the inert gas is replaced with hydrogen or VSS (the hydrogen content in the VSS should be at least 80 vol.%), The temperature is raised to the temperature of the process and raw materials are supplied with compliance with the molar ratio of hydrogen: raw materials equal to (0.3-10): 1. The volumetric feed rate of 0.5-4.0 h ^-1 . In the reactor, isomerization of paraffin hydrocarbons, hydrogenation of unsaturated and aromatic compounds, and partial cracking of hydrocarbons with the formation of C ₁ -C ₄ gases occur.

The catalyst is prepared as follows.

The catalyst carrier is obtained by mixing the hydroxides of iron, manganese, titanium, zirconium and aluminum in compliance with the required molar ratio of oxides. The hydroxide mixture is extruded, dried and calcined in a stream of dry air at a temperature of 500-900 ° C.

The resulting metal oxide composition is impregnated with solutions of platinum and / or palladium and / or iridium and / or rhodium and / or ruthenium compounds. Sulfuric acid is added to the impregnation solution to provide the desired ratio of oxygen-containing sulfur ion and oxide composition. After impregnation, the catalyst is dried and calcined at a temperature of 400-700 ° C.

The possibility of implementing the method is confirmed by the following examples.

The experiments were carried out in a flow pilot installation. The catalyst loading was 4 cm ³ . To dry the nitrogen-oxygen mixture, calcined NaX zeolite was used. The moisture content in the gas mixture before entering the isomerization reactor should be no more than 5 ppm vol. The multiplicity of circulation of the gas mixture was 550-600 nm ³ per m ^{3 of} catalyst per hour. The isomerization process was carried out in the temperature range of 100-220 ° C at a pressure of 1.0-3.5 MPa, the volumetric feed rate (V) of 0.5-4 , 0 h ^-1 and a molar ratio of hydrogen: feed (Q) equal to (0.3-10): 1. As raw materials used hydrotreated straight-run gasoline fraction NK-70 ° C with an octane number according to the motor method (MOC) - 67 points of the following composition, wt.%:

isobutane 0.01 n-butane 0.31 isopentane 15.41 n-pentane 34.03 cyclopentane 4.20 2,2-dimethylbutane 0.51 2,3-dimethylbutane 1.45 2-methylpentane 14.55 3-methylpentane 7.81 n-hexane 14.92 methylcyclopentane 5.00 cyclohexane 0.47 benzene 1.22 the amount 0.11 hydrocarbons C ₇ impurities, ppm: sulfur 0.5 water 10 chlorine 1,0 nitrogen 0.5

The reaction products were analyzed by gas-liquid chromatography on a stream using a capillary column with an OV-101 liquid phase.

The octane number of the stable isomerizate was calculated based on the data of chromatographic analyzes and the following base of calculated octane numbers of the components according to the formula

O = Σ (x _i × o _i ) / 100

where: x _i - mass fraction of hydrocarbon, wt.%;

o _i is the octane number of the hydrocarbon, paragraph.

Database of octane numbers.

Hydrocarbon Urine IOCH propane one hundred 105.7 isobutane 97.6 100,2 n-butane 93.5 95.0 isopentane 90.0 93.5 n-pentane 61.3 61.7 cyclopentane 85.0 102.3 2,2-dimethylbutane 95.5 95.0 2,3-dimethylbutane 104.3 105.0 2-methylpentane 74.9 74,4 3-methylpentane 76.0 75,5 n-hexane 30,0 31,0 methylcyclopentane 85.0 96.0 cyclohexane 77,2 84.0 benzene 114.8 120.0 ΣC ₇₊ 71.0 82.0

The values of the molar coefficients of the metal oxides in the composition of the catalyst oxides and the mass ratio of the sulfuric acid ion to the composition of the oxides are presented in table No. 1. The conditions for activation of the catalyst and the test results of the isomerization method are presented in table No. 2.

Example No. 1

In the reactor loaded with 4 cm ³ catalyst composition, wt.%:

platinum 0.3 sulfuric acid 9.2 and he composition 90.5 oxides

dry nitrogen containing 1.5 vol.% oxygen is supplied with a circulation rate of 570 nm ³ per m ^{3 of} catalyst per hour under a pressure of 1.5 MPa and heated at a speed of 10 ° C per hour to a temperature of 150 ° C, maintained at this temperature 5 hours, and then raise the temperature at the same speed and spend every 50 ° C for the time shown in table No. 2. The maximum heating temperature was 500 ° C.

After the activation cycle of the catalyst, it is cooled in a stream of dry nitrogen at a speed of 20 ° C to a temperature of 110 ° C, nitrogen is replaced with hydrogen, the pressure and temperature are raised to 2.8 MPa and 150 ° C, respectively, and feed is supplied with a bulk velocity of 2.0 h ^{- 1} . At the same time, the molar ratio of hydrogen: feed is 5.0: 1.

The test results of the isomerization method are presented in table No. 2.

Example No. 2

The method is carried out according to example No. 1 with the difference that a composition catalyst is used, wt.%:

platinum 0.4 palladium 0.4 sulfuric acid 4.0 and he composition 95.2 oxides

and activation is carried out in a stream of a nitrogen-oxygen mixture with an oxygen content of 0.1 vol.% at a pressure of 2.5 MPa and a maximum heating temperature of 520 ° C. The exposure time at appropriate temperatures is presented in table No. 2. Cooling in a stream of dry nitrogen is carried out to a temperature of 100 ° C, and after replacing the nitrogen with hydrogen, the pressure is raised to 3.5 MPa and the feed is supplied at a rate of 0.5 h ^-1 with a molar ratio of hydrogen: feed 0.3: 1.

The test results of the isomerization method are presented in table No. 2.

Example No. 3

The method is carried out according to example No. 1 with the difference that a composition catalyst is used, wt.%:

iridium 0.1 sulfuric acid 15.0 and he composition 84.9 oxides

and activation is carried out in a stream of argon-oxygen mixture, with an oxygen content of 3.0 vol.% at a pressure of 0.5 MPa and a maximum heating temperature of 450 ° C. The exposure time at appropriate temperatures is presented in table No. 2. Cooling in a stream of dry argon is carried out to a temperature of 120 ° C, and after replacing the argon with hydrogen, the pressure is raised to 1.0 MPa, the temperature is up to 220 ° C and the feed is supplied at a rate of 4.0 h ^-1 at a molar ratio of hydrogen: feed 10, 0-1.

The test results of the isomerization method are presented in table No. 2.

Example No. 4

The method is carried out according to example No. 1 with the difference that a composition catalyst is used, wt.%:

rhodium 0.5 sulfuric acid 9.5 and he composition 90.0 oxides

and activation is carried out in a stream of a nitrogen-oxygen mixture, with an oxygen content of 1.2 vol.% at a pressure of 1.2 MPa and a maximum heating temperature of 450 ° C. The exposure time at appropriate temperatures is presented in table No. 2. Cooling in a stream of dry nitrogen is carried out to a temperature of 120 ° C, and after replacing nitrogen with hydrogen, the pressure is raised to 3.5 MPa and the feed is supplied at a rate of 2.5 h ⁻¹ with a molar ratio of hydrogen: feed 6.0: 1.

The test results of the isomerization method are presented in table No. 2.

Example No. 5

The method is carried out according to example No. 1 with the difference that a composition catalyst is used, wt.%:

ruthenium 0.6 sulfuric acid 9.5 and he composition 89.9 oxides

and activation is carried out in a stream of a nitrogen-oxygen mixture with an oxygen content of 3.0 vol.% at a pressure of 1.1 MPa and a maximum heating temperature of 450 ° C. The exposure time at appropriate temperatures is presented in table No. 2. Cooling in a stream of dry nitrogen is carried out to a temperature of 120 ° C, and after replacing nitrogen with hydrogen, the pressure is raised to 2.8 MPa, the temperature is up to 150 ° C and the feed is supplied at a rate of 2.5 h ^-1 at a molar ratio of hydrogen: feed 5, 0-1.

The test results of the isomerization method are presented in table No. 2.

Example No. 6 (comparative)

The method is carried out according to example No. 2 with the difference that the activation is carried out in a stream of nitrogen-oxygen mixture, with an oxygen content of 0.01 vol.%.

The test results of the isomerization method are presented in table No. 2.

Example No. 7 (comparative)

The method is carried out according to example No. 1 with the difference that the activation is carried out in a stream of a nitrogen-oxygen mixture, with an oxygen content of 3.3 vol.%.

The test results of the isomerization method are presented in table No. 2.

Example No. 8 (comparative)

The method is carried out according to example No. 4 with the difference that in the activation process, the minimum exposure at a temperature of 150 ° C is 2.5 hours.

The test results of the isomerization method are presented in table No. 2.

Example No. 9 (comparative)

The method is carried out according to example No. 2 with the difference that in the activation process, the minimum exposure at a temperature of 250 ° C is 2.5 hours.

The test results of the isomerization method are presented in table No. 2.

Example No. 10 (comparative)

The method is carried out according to example No. 4 with the difference that in the activation process, the maximum exposure at a temperature of 350 ° C is 26 hours.

The test results of the isomerization method are presented in table No. 2.

Example No. 11 (comparative)

The method is carried out according to example No. 2 with the difference that in the activation process, the maximum exposure at a temperature of 450 ° C is 26 hours.

The test results of the isomerization method are presented in table No. 2.

Example No. 12 (comparative)

The method is carried out according to example No. 1 with the difference that during the activation process the pressure of the nitrogen-oxygen mixture is 0.3 MPa.

The test results are presented in table No. 2.

Example No. 13 (comparative)

The method is carried out according to example No. 1 with the difference that during the activation process the pressure of the nitrogen-oxygen mixture is 2.8 MPa.

The test results are presented in table No. 2.

Example No. 14 (comparative)

The method is carried out without activation of the catalyst. The catalyst is dried in a stream of nitrogen until the moisture content at the outlet of the reactor is 50 ppm, then it is cooled to 100 ° C, nitrogen is replaced with hydrogen, and then they act as in example No. 1.

The test results are presented in table No. 2.

Example No. 15 (comparative)

The method is carried out according to example No. 1 with the difference that in the process of activation the temperature rise is carried out at a speed of 20 ° C per hour.

The test results are presented in table No. 2.

Example No. 16 (comparative)

The method is carried out according to example No. 1 with the difference that in the process of activation the temperature rise is carried out at a speed of 5 ° C per hour.

The test results are presented in table No. 2.

Example No. 17 (prototype)

The isomerization method is carried out by activating the catalyst with a dry nitrogen-oxygen mixture containing 0.000002 vol.% Oxygen, heated to 530 ° C at a speed of 50 ° C per hour and kept at this temperature for 6 hours. Then reduce the temperature to 110 ° C at a rate of 20 ° C per hour, replace the nitrogen mixture with hydrogen, raise the pressure and temperature to 2.8 MPa and 150 ° C and feed. The experiment is carried out in the conditions of example No. 1.

The test results are presented in table No. 2.

Analysis of the test results shows that the proposed method for the isomerization of light gasoline fractions with preliminary activation of the catalyst is highly efficient. This is illustrated by examples No. 1-5. The resulting gasoline component (isomerizate) has a higher octane number than the method without catalyst activation and the prototype method (higher by 2.4 and 2.3 points, respectively), and the octane number increase on average is 20.7% against 17, 3% according to the method without activation of the catalyst, 17.6% according to the prototype method with a low rate of temperature rise and 17.5% with a high rate of temperature rise. In this case, the yield of isomerizate remains almost unchanged.

However, such indicators are achievable only when the activation of the isomerization catalyst in an inert gas medium containing the claimed amount of oxygen in the proposed activation conditions. So, for example, a decrease in the oxygen content in the activation medium (Project No. 6), a minimum exposure time when certain processing temperatures are reached (Project No. 8 and 9), a decrease in pressure during the activation process (project No. 12) below the stated limits, and also, an increase in the rate of temperature rise (pr. 15) leads to a decrease in all process indicators. An increase in the oxygen content in the catalyst activation medium, pressure during the activation process, holding time when certain processing temperatures are reached, and also a decrease in the rate of temperature rise does not lead to further improvement of the isomerization process parameters (pr. No. 7, 10, 11, 13 and 16).

Thus, the method of isomerization of light gasoline fractions with preliminary activation of the catalyst allows one to obtain an environmentally friendly high-octane component of motor gasoline with a much higher octane number and can be successfully implemented in large-capacity oil refining and petrochemical industries.

Table number 1 The values of the coefficients in the composition of the catalyst oxides Example No. Mole ratios of oxides The ratio of sulfuric acid ion to oxide composition x 10 ³ y 10 ³ z · 10 ³ n · 10 ² m · 10 ² one 1.83 1,2 1.31 14.65 68.85 0.102 2 0.06 1,2 1.31 14.65 68.8 0.178 3 3.6 1,2 1.31 14.65 68.8 0.178 four 1.83 0.11 1.31 14.65 68.8 0.178 5 1.83 1,2 1.31 21.5 63.3 0,042

Claims (5)

1. The method of isomerization of light gasoline fractions with pre-activation of the catalyst at elevated temperature and pressure by activating the catalyst with a dry inert gas containing oxygen at an elevated temperature, lowering the temperature in an inert gas stream without oxygen, replacing the inert gas with hydrogen, followed by contact of the feedstock with the catalyst in a stream of hydrogen, characterized in that the activation of the catalyst is carried out in a stream of inert gas containing 0.1-3.0 vol.% oxygen, at a pressure of 0.5-2.5 MPa, when heated at at a temperature of 10 ° C per hour to a maximum temperature of 450-520 ° C, and every 50 ° C, hold at this temperature for 3-24 hours 2. The method of isomerization of light gasoline fractions with preliminary activation of the catalyst according to claim 1, characterized in that the maximum activation temperature of the catalyst is 450-520 ° C, and after heat treatment the catalyst is cooled in a stream of inert gas without oxygen to a temperature of 100-120 ° C , replace the inert gas with hydrogen or a hydrogen-containing gas, raise the temperature to the temperature of the process and feed. 3. The method of isomerization of light gasoline fractions with preliminary activation of the catalyst according to claim 2, characterized in that nitrogen or argon is used as an inert gas. 4. The method of isomerization of light gasoline fractions with preliminary activation of the catalyst according to claim 2, characterized in that the process is carried out at a temperature of 100-220 ° C, a pressure of 1.0-3.5 MPa, a molar ratio of hydrogen: raw material (0.3- 10): 1 on the catalyst composition, wt.%:
Group 8A metal 0.1-0.8 sulfuric acid ion 4-15 metal oxide composition up to 100 5. The method of isomerization of light gasoline fractions with preliminary activation of the catalyst according to claim 4, characterized in that platinum and / or palladium and / or iridium and / or rhodium and / or ruthenium are used as the group 8A metal, and the composition metal oxides is:
xFe ₂ O ₃ · yMnO ₂ · zTiO ₂ · nAl ₂ O ₃ · mZrO ₂
at molar values of the coefficients:
x = (0.06-3.6) · 10 ^-3
y = (0.11-2.3) · 10 ^-3
z = (0.12-2.5) · 10 ^-3
n- (7.8-21.5) · 10 ^-2
m = (63.3-74.7) 10 ^-2 .