CS240662B1 - A method for hydrotreating petroleum distillates to improve their quality - Google Patents

Abstract

The solution relates to a method of hydrotreating petroleum distillates in order to improve their quality by hydrotreating sulfur compounds, hydrogenation of aromatics and unsaturated hydrocarbons, isomerization of n-paraffins, or selective hydrocracking of hydrocarbons using catalysts based on tungsten-nickel-aluminaaluminosilicate or molybdenum-nickel-aluminaaluminosilicate, optionally activated with compounds of fluorine, phosphorus, boron and Additives, with an increased content of catalytic substances, especially tungsten and nickel. In the aforementioned catalysts, nickel or part thereof may be replaced by cobalt.

Description

The invention relates to a method for hydrotreating petroleum distillates in order to improve their quality by hydrotreating sulfur and nitrogen compounds, hydrogenation of aromatics and unsaturated hydrocarbons, isomerization of n-paraffins, or selective hydrocracking of hydrocarbons using catalysts based on tungsten-nickel-alumina-aluminosilicate, or molybdenum-nickel-alumina-aluminosilicate, or activated by fluorine, phosphorus, boron, etc. compounds, with an increased content of catalytic substances, especially tungsten and nickel in the catalyst. In the above catalysts, nickel or part thereof may be replaced by cobalt.

Currently, hydrotreating in a hydrogen stream using a catalyst based on Co-MoAlgOj or Co-Ni-Mo-Al ₂ 0 ₃ is mainly used to improve the quality of petroleum distillates and various hydrocarbon fractions. These catalysts are characterized by good desulfurization properties, but relatively low hydrogenation and isomaltation, or hydrocracking properties.

When processing hydrocarbon fractions used for the production of, for example, technical gasolines, such as white spirit, gasoline for cleaning purposes, or hydrocarbon fractions used as aviation fuels, jet kerosene, diesel fuel, etc., which contain a large amount of aromatic hydrocarbons, during hydrorefining using these catalysts based on Co-Mo-alumina, the finished products produced do not meet the increased demands placed on their quality at present.

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In order to achieve increased quality and requirements for these products, it is necessary to work at high pressures, which requires increased investment and maintenance costs for the equipment used and often increased hydrogen consumption, etc.

Increased quality of these products can be achieved by various processes, which consist, for example, in the use of a combination of a Co-Mo-AlgOg and Ni-Al ₂ 0 ₃ or Pt-Al ₂ 0 ₃ catalyst and two-stage hydrorefining, whereby in the first stage the processed hydrocarbon raw material is desulfurized on a Co-Mo-AlgOg catalyst to a very low sulfur content of around 1 to 5 ppm and then subjected in the second stage to additional hydrogenation of aromatics using, for example, Ni-Al ₂ 0 ₃ or Pd-Al ₂ 0 _3. This method of processing oil fractions provides good results, but is demanding for perfect desulfurization of the raw material in the first stage, because in the case of imperfect desulfurization, in the second stage there is a gradual loss of activity of catalysts based on nickel, palladium or platinum, which are very sensitive to sulfur. Another disadvantage is the fact that the product from the first stage of hydrogenation must first be condensed, stripped of HgS, and then processed in the second stage.

However, it has now been found that when processing the above hydrocarbon fractions, such as white spirit, cleaning spirit, jet kerosene, diesel fuel, etc. by hydrotreating in a stream of hydrogen using catalysts based on tungsten-nickel or tungsten-nickel-alumina-aluminosilicate or molybdenum-nickel-alumina or aluminosilicate, optionally activated with compounds of fluorine, phosphorus, boron, etc., with an increased content of catalytic substances, especially tungsten and nickel, a significant improvement in the quality of these products can be achieved. The catalysts can also be based on alumina and aluminosilicates containing Mo0 ₃ -Co0-Ni0.

The essence of the invention, which relates to a method for hydrotreating petroleum distillates in order to improve their quality, in particular petroleum fractions, white spirit, gasoline for cleaning purposes, diesel fuel, in which hydrotreating of sulfur and nitrogen compounds, saturation of aromatics and unsaturated hydrocarbons, isomerization of n-paraffins and selective hydrocracking using catalysts based on tungsten and nickel, or molybdenum and nickel or cobalt, supported on alumina and aluminosilicate, consists in that petroleum distillate with a distillation range of 140 to 350°C, or petroleum fraction with a distillation range of 140 to 240°C, is passed in a stream of hydrogen through a catalyst with very finely dispersed catalytic substances, prepared by mutual coprecipitation of single components and containing 10 to 40% wt. tungsten oxide WO^ and 3 to 20 wt. nickel oxide NiO or 10 to 40 wt. molybdenum oxide MoO-j and 3 to 20 wt. nickel oxide NiO or cobalt oxide CoO, 20 to 85 wt. aluminum oxide AlgO-^ and 0.5 to 20% silicon oxide SiOg at a pressure of 3.0 to 7.0 MPa and a temperature of 250 to 450°C. The catalyst may contain as an activator the addition of fluorine, phosphorus or boron compounds either individually or in a mixture in an amount of 0.5 to 10 wt.

A more detailed method of preparing the aforementioned catalysts was described in AO 207 938, AO 206 844, AO 206 907.

Using these catalysts, it is possible to achieve a higher degree of hydrotreating of unsaturated hydrocarbons, or hydrolysis of nitrogen or sulfur-containing compounds of aromatic character. These catalysts are suitable for processing both light petroleum distillates and for hydrogenation of middle distillates, especially containing sulfur compounds and 10 to .25% aromatic hydrocarbons, which adversely affect some quality indicators, such as luminescence number, smokeless flame height, diesel index, crystallization point, etc.

Under the above operating conditions and using the above catalysts, the quality of both light and middle distillates used as solvents, white oils, jet fuels, diesel fuels, etc. can be significantly improved.

It has been found that this type of catalyst, e.g. ^based on tungsten and nickel, supported on alumina and aluminosilicate, is exceptionally suitable for the hydrogenation of aromatics, reduction of sulfur content, isomerization of alkenes, selective hydrocracking of hydrocarbons and thus improving the hydrocarbon composition of the aforementioned petroleum distillates.

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- 4 The catalysts mentioned, containing 10 to 40 wt. % WO^ or MoOj, 3 to 20« NiO or CoO, 0.5 to 20% SiO _g and 20 to 85% AlGO^, optionally activated with fluorine, phosphorus or boron compounds (either individually) or in a mixture in an amount of 0.5 to 10 wt. %, are characterized by high hydrogenation activity.

A high degree of hydrotreating of these hydrocarbon fractions, in particular a reduction in sulfur content, Br-index, crystallization point, aromatic content, increase in isoparaffins, etc., is achieved by using medium hydrogen pressures in the range of 3.0 to 7.0 MPa, especially at a pressure of 5.0 to 6.0 MPa and a throughput of 1.0 to 2*.0 vol./vol./h.

If it is necessary for the hydrorefining of the above fractions to proceed selectively without hydrocracking and isomerization, then it is advantageous to use catalysts, especially ^based on tungsten-nickel-alumina, or molybdenum-nickel-alumina with a higher content of catalytic substances, especially W0p MoO2 or NiO and with a low content of SiO2.

The term alumina refers to industrially produced aluminum oxide stabilized with a small amount of around 0.1 to 2% by weight of SiO2.

In the event that it is desired that the hydrotreating be accompanied by selective hydrocracking, especially of higher-boiling hydrocarbons, or their isomers, it is preferable to use catalysts based on tungsten-nickel-aluminosilicate or molybdenum-nickel-aluminosilicate, optionally activated with fluorine, phosphorus, boron compounds, etc. The petroleum fraction or hydrocarbon fraction of a different distillation range may be subjected to pretreatment by hydrotreating using a Co-Mo-Alg O3 catalyst before hydrogenation on a catalyst based on tungsten-nickel-alumina and aluminosilicate, optionally activated with fluorine, phosphorus or boron compounds.

The catalysts mentioned can be used in the form of tablets or extrudates, etc., of various lengths and diameters in the oxidic state, which are annealed, reduced and sulphurised before use or during use. The method of activating the catalyst in a stream of Hg and HgS or other sulphur compounds, or hydrocarbons containing sulphur compounds, e.g. raw material used for hydrotreating or circulating gas containing hydrogen and sulphur compounds, is carried out by heating the catalyst with a gradually increasing temperature from 100°C up to 450°C. The duration of the catalyst activation lasts 8 to

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- 5 24 hours or longer as needed so that the catalyst is completely sulfurized, which is determined from the content of sulfur compounds in the inlet and outlet gas from the catalyst.

The actual hydrogen refining can be carried out at temperatures of 200 to 450°C, preferably 350 to 400°C, at a pressure of 3.0 to 7.0 MPa, preferably 5.0 to 6.0 MPa, at a throughput of 0.5 to 2.5 vol./vol./h, preferably 1.0 to 2.0 vol./vol./h, and at a hydrogen-containing gas flow rate of 100 to 1,000 m3/flp/h, preferably 300 to 500 m3/m3/h.

As starting materials under the specified operating conditions and the specified type of catalyst, hydrocarbon fractions of various distillation ranges can be used, such as gasolines, kerosene _fractions , diesel fuel.

Example 1

Comparison of the efficiency of the catalysts according to the invention and the cobalt-molybdenum catalyst on alumina in the hydrorefining of a petroleum fraction with a distillation range of 140 to 240°C

Catalyst Hydrogenation product density aromatics lumin.number flame emission height non-smoke

1. C0O-M0 O3 -Alg O3 0.787 16.4 55 25 2. NiOwMoO-j-AlgO^-SiOg 0.787 15.0 55 t5 3. NiO-WO^-AlgO^-SiOg 0.785 13.4 57 26 4. NiO-WC ₃ -Al ₂ O ₃ -SiO ₂ 0.785 13.5 57 26 5. NiO-WO ₃ «rAl ₂ O ₃ -SiO ₂ -FP 0.781 10.5 59 26.5 6. Co0-Mo0 ₃ -Al ₂ 0 ₃ -SiO ₂ 0.784 14.7 56.5 25.5 7. Co0-Mo0 ₃ «-Al ₂ 0 ₃ -Si0 ₂ -F 0.783 14.0 56.8 25.8

Catalyst composition:

1. CoO 3 wt%, MoO^ 18 wt%,

2. NiO 4 wt%, MoO^ 18 wt%,

3. NiO 10 wt.%, WO-j 30 wt.%, remainder Al ₂ O ₃

0.5% SiOg, remainder AlgO^ 0.5% SiOg, remainder AlgO240 002

- 6 4. NiO 10 wt%, WO^ 33 wt%, SiOg 15 wt%, remainder AlgO^

5. NiO 10 wt. %, WO^ 35 wt. %, SiOg 15 wt. %, F 4 wt. %, P 4 wt. %, remainder AlgO-j

6. CoO 3.0 wt%, MoO^ 19.1 wt%, SiOg 1.2 wt%, remainder ^A1 2°3

7· CoO 3.0 wt%, MoO^ 18.5 wt%, SiOg 0.7 wt%,

F 1.0 wt%, remainder AlgO^

The values given in the table were achieved with a kerosene fraction dist. range of about 140 to 240 °C and a sulfur content of 0.16 wt. %, density of 0.787, aromatic content of 18.6 wt. % at a temperature of 350 °C, a pressure of 5.0 to 6.0 MPa, a throughput of 1-2 vol./vol./h and a Hg/CH ratio of about 400 1/1. From the given values it is evident that tungsten-nickel-based catalysts have a higher hydrogenation activity and the kerosene fraction processed under the given conditions is characterized by a significant improvement in quality. In particular, nickel-tungsten-based catalysts with a higher content of catalytic substances and activated by fluorine and phosphorus compounds appear to be very active.

Example 2

The petroleum fraction with a distillation range of approximately 140 to 240°C, the composition of which is given in the table, was hydrogenated using tungsten-nickel catalysts, namely catalyst A containing 30 wt. % WO-^, 10 wt. % NiO, 0.5 % SiO2 and the rest AlgO-j and on catalyst B containing 32 % W0p 12 % Ni 0, % SiO ₂ , 1 % F and the rest AlgO^. The characteristics of the raw material, product and operating conditions are summarized in the following table.

Raw material Product from catalyst A B working conditions:

temperature °C 350 350 350 350 Pressure MPa 6.0 6.0 6.0 6.0 enforcement volume/volume/h 1.0 2.0 1.0 2.0 Characteristics: specific gravity at 2O°C 0.789 0.786 0.786 0.781 0.785 aniline point I °C 56.7 61.2 59.9 63.0 60.0

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aniline point 11 °C 71.8 flavors % wt. 18.6 Br-index 1953 sulfur % wt. 0.169 luminis. no. 53 height of smoke, flame 24 dest, curve: z. d. °C 130 10% vol. 172 50% vol. 195 90% vol. 222 95% vol. 231 k. d. 243

71.8 72.0 71.2 72.0 13.4 15.1 10.4 15.0 131 150 110 148 0.005 0.0065 0.0048 0.0i 59 57 59.1 57.0 26 25.5 27.5 25.5 125 126 125 127 170 172 171 172 194 195 192 193 223 225 221 223 230 232 241 242 241 245 241 242

From the values given in the table it can be seen that both catalysts mentioned significantly improve the quality of the kerosene fraction, especially in terms of luminescence numbers and the height of the smokeless flame.

Example 3

The hydrocarbon fraction with a distillation range of 140 to 340 °C was hydrogenated using a tungsten-nickel-alumina silicate catalyst activated with fluorine. The catalyst had the following composition:

% wt. WO ₃ , 14% NiO , 15% S10 ₂ , 1.5% F and the rest Al ₂ 0 ₃ .

The raw material and product characteristics and the operating conditions used are summarized in the following table.

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Raw material Product Distilled jet kerosene Working conditions: temperature °C 350 pressure MPa 6.0 enforcement volume/volume/h 1.0 Characteristics: specific gravity at 20 °C 0.802 0.769 0.781 annealing point I °C 61.1 64.8 59.0 annealing point XI °C 77.1 77.0 70.9 flavors % wt. 19.7 15.0 14.9 sulfur % wt. 0.70 0.014 0.0055 lumin. art. 56 height of non-smoke flame 26 dest. curve: z. d. °C 142 106 135 10% vol. 144 131 160 50% vol. 231 223 191 90% vol. 312 307 225 95% vol. 320 319 230 k. d. 340 336 239

A petroleum fraction of 135 to 240 °C was distilled from the hydrogenation product, the composition of which is given in the table.

Example 4

The heavier gasoline fraction, the so-called white gasoline produced from petroleum distillates, was further refined by hydrogenation using a tungsten-nickel-alumina-fluorine catalyst. The catalyst had the following parameters: rods diameter 1.0 mm, length 5 to 10 mm, WOj content 34 wt. %, 14 % NiO, 10 % Si0 ₂ , ^1>5 % ^F > remainder AlgO^. The operating conditions and characteristics of the starting material and the product are given in the following table.

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Raw material Product Working conditions: temperature °C 350 pressure MPa 6.0 enforcement volume/volume/h 1.0 Characteristics: specific gravity at 20 °C 0.772 0.765 annealing point I °C 55.1 61.0 annealing point II °C 67.5 66.2 flavors % wt. 14.2 6.2 sulfur % wt. 0.007 0.001 dest. curve: z. d. °C 146 144 10% vol. 153 153 50% vol. 161 162 90% vol. 177 179 95% vol. 183 184 k. d. 200 202

From the values given in the table it can be seen that the hydrogenation of aromatics depends to a large extent on the sulfur content in the feedstock. If the sulfur content in the feedstock is low, hydrogenation of aromatics can be achieved at a relatively low pressure of around 50% or more. ίο -

Claims (3)

SCOPE OF THE INVENTION 240 662 Process for the hydrotreating of petroleum distillates for improving their quality, in particular kerosine fractions, white spirit, purification gasoline, diesel fuel, in which hydrotreating of sulfur and nitrogen compounds, saturation of aromatic and unsaturated hydrocarbons, isomerisation of n-paraffins and selective hydrocracking in the presence of catalysts based on tungsten and nickel, or molybdenum and nickel or cobalt, deposited on alumina and aluminosilicates, characterized in that the petroleum distillate of the distillation range of 140 to 35 ° C or the kerosene fraction of the distillation range of 140 to 240 ° C and very finely divided catalytic substances, prepared by coprecipitation of the components and containing 10 to 40% by weight of tungsten oxide WO3 and 3 to 20% by weight of nickel oxide; 10 to 40 wt. MoO 2 and 3 to 20 wt% NiO or cobalt CoO, 20 to 85 wt% AlgO 4 and 0.5 to 20% SiO 2 at 3.0 to 7.0 MPa and temperature 250-450 ° C. 2. A process according to claim 1, wherein the catalyst comprises as activator the addition of fluorine, phosphorus or boron compounds either individually; or in a mixture of 0.5 to 10% by weight · Printed by the Moravian Printing Works, operation 12, the class of People's Militia 3, Olomouc