DE1470591A1 - Use of a catalyst, which contains platinum on a silica-alumina carrier, to reduce the content of aromatic hydrocarbons in a petroleum distillate - Google Patents

Description

Dr. Ing. E. BERKENFELD · Dipl.-Ing. H. BERKENFELD, patent attorneys, Cologne

Annex file number P 14 70 591.0

to enter Y] ₀ July 1 968 3θίΐ / name d. Note 3.A.

Use of a catalyst which contains platinum on a silica-alumina carrier for reducing the content of aromatic hydrocarbons in a petroleum distillate.

The petroleum distillates that boil in the range of 60 to 350 ° C and which are used either as fuel for plug tools or as heating fuel for household purposes or as solvents aromatic compounds, the presence of which can be a hindrance.

The calorific value of a hydrocarbon is proportional to the ratio Hydrogen - carbon, so that cyclic saturated hydrocarbons are very valuable than corresponding aromatic ones Hydrocarbons. In addition, there is combustion cleaner and corrosive to the extent that the content of aromatic hydrocarbons in the fuel is lower. It is therefore understandable that one is interested in

(£> in the fuels intended for motor propellants the content

- »» to reduce aromatic hydrocarbons.

An important property of the petroleum oils used for lighting purposes and for heating purposes is that they are as good as possible show little tendency to smoke. In certain solvents, the reduction in the aromatic content is evident

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prescribed for hygienic reasons; the fumes of these, hydrocarbons are toxic. ; ■ '. ·

There are various methods of reducing or eliminating the aromatic hydrocarbons from petroleum distillates known, for example cleaning with sulfuric acid, extraction by means of sulfur dioxide, adsorption suitable pesticides or catalytic hydrogenation. The first three methods eliminate a faction that is rich is of aromatic hydrocarbons, and hence there is a disadvantage that the yield of the purified product is low is. This does not apply to the catalytic hydrogenation, which also has the advantage that it can be carried out in a simple manner and can be carried out economically.

Purely the hydrogenation of the aromatic mono- and polycyclic Kh-

different types of hydrogen can be used as catalysts: nickel, deposited on kieselguhr or silica, sulphides of Nickel and tungsten, precious metals such as platinum.

As is known from British patent specification 838 751, nickel oxide can be used to reduce the aromatic content of hydrocarbon mixtures carry out by hydrogenation at temperatures and pressures which are not too high; however may the hydrocarbon mixture does not contain more than 20 ppm sulfur, and the disadvantage must also be accepted,

and that nickel oxide is irreversibly poisoned by sulfur / not

can be heated above about 400 ° C without its activity - i is completely lost. As a result of sensitivity to sulfur-containing compounds lower the activity of the I.

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Catalyst, to the extent that "as sulfur-containing compounds do start on; the excellent heat resistance of the nickel catalyst It does not allow its regeneration by combustion by means of oxygen of the impurities deposited on the catalytic converter to undertake.

The sulphides of nickel and tungsten can be well defined Amounts on suitable carrier substances, such as alumina or even without a carrier, can be used as catalysts. These sulfides have the advantage that they are insensitive to sulfur-containing compounds, but as such they are less active than the corresponding pure metals. Therefore the working conditions have to be much more complex: you have to work at very high temperatures work, the space velocity must be kept relatively low and you have to provide increased pressures. Especially this one last condition is critical, and notable results will only be obtained when at pressures as high as about

ο
100 kg / cm or higher is worked.

In contrast, platinum does not have the disadvantages inherent in the sulphides of nickel and tungsten, as the examples show. Nevertheless, the platinum catalysts are poisoned by sulfur. Their use therefore presupposes that the sulfur which is present in the feed is reduced very greatly so that the hydrogenation can be continued for a long period of time without the catalyst having to be regenerated. - '■' ■,.

It was found that very high sulfur contents are tolerated in use: ₅ köi} n®n; i if the platinum is on silica-alumina instead.

is applied to ^ clay alone. ,. ■ · j

Original

809901 / 067.4,; ;

Such a catalyst is known per se from British patent 796 175. This patent describes the 'preparation of catalysts which are also suitable for hydrogenation from chelates of the metals of groups VI and VIII of the Periodic Table, which are applied to supports such as aluminum oxide, silica-alumina (containing more than 75 $ silica) and alumina. It cannot be inferred from this patent that a platinum catalyst applied to silica-alumina is distinguished by a remarkable resistance to sulfur and, for this reason, is outstandingly suitable for dearomatizing petroleum fractures. _r

The present invention relates to a continuous process for reducing the content of aromatic hydrocarbons in petroleum fractions that boil between 60 and 350 C, and wherein the content of sulfur is set in advance. According to the invention one uses one based on silica-alumina applied platinum catalyst and works in the presence of hydrogen under pressure and at a temperature and a space velocity which are determined by the desired degree of hydrogenation of the aromatics and the sulfur content of the feed.

The present invention relates in particular to a continuous process for reducing the content of aromatic hydrocarbons in a petroleum distillate which has a maximum sulfur content of 300 ppm and which ^{boils in the range from 60 to 350 °} C. by hydrogenating this distillate in the presence of a catalyst which is composed of platinum and of silica-alumina as the support, wherein at least 75 wt -.% of silica are present.

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The subject of the invention is therefore the use of a catalyst, which contains platinum on a silica-alumina carrier, to reduce the content of aromatic hydrocarbons in a petroleum distillate, which is in the range of 60 to 350 ° C passes over and whose weight content of sulfur is a maximum of 300 ppm, by hydrogenation.

The influence of the carrier substance can possibly be explained by this be that this has a more or less pronounced effect on the hydrogenation process in which the sulfur-containing Connections are destroyed. However, this is only a theoretical attempt at explanation and is by no means intended to explain the meaning of the present invention.

The catalyst used in the invention contains 0.1 to 1 wt -.% Of platinum, preferably 0.3 to 0.8 wt .- ^. The hydrogenation is advantageously carried out under the following conditions:

2 2

Pressure : 5 to 70 kg / cm, preferably 20 to 55 kg / cm

Temperature : 100 to 400 ° C, preferably 250 to 350 ° C room velocity ; 0.1 to 20 volumes of the feed per volume of the catalyst per hour, preferably 0.5 to 10 v / v / h.

Ratio hydrogen / input ; 100 to 3000 liters of hydrogen

at normal temperature and normal pressure (N.T.P.) per liter of use, preferably 150 to 2500 liters.

It is advantageous to choose the temperature as high as possible in order to increase the rate of the reaction; however, this tera-

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temperature can be kept below a limit temperature at which a sign reversal of the equilibrium constant and consequently the direction of the reaction is reversed. If you work at a higher temperature than this limit temperature, so will favors the dehydrogenation reaction more than the hydrogenation.

Adjust the sulfur content in the insert depending on the desired one Degree of saturation of the aromatics, and the process can be carried out without interruption for very long times. The sulfur content can be reduced by hydrogenating the petroleum distillate in the presence of a cobalt oxide catalyst and molybdenum oxide on alumina according to methods used in refining petroleum distillates.

The temperature to be used in the process of the invention is relatively low, the catalyst is not severely coked, and it is therefore not necessary to carry out a regeneration by burning off. It can happen, however, that the activity of the catalyst decreases because too large an amount of sulfur happened to be introduced, or because the introduction of the feed was interrupted for several hours. In both of these cases, the initial activity can be restored in a simple manner by reapplying fresh feed and / or by increasing the reaction ^{temperature to 400 °} C. over a fairly short period of time, about 1/2 to 2 hours; the other conditions, namely the pressure, the ratio of hydrogen to the input and the throughput, remain the same as indicated above for the reaction.

The invention is explained in more detail by means of the following examples

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wrote; these are for illustrative purposes only and are intended in no way limit the invention.

example 1

A petroleum fraction is pretreated by hydrogenation according to a procedure known from the refining of petroleum distillates, to reduce the content of sulfur. The various sulfur-containing inserts listed below were made by mixing obtained from treated distillates and untreated distillates, the characteristics of which are as follows:

Characteristic values not treated
distillate treated
distillate Density 15 ° C / 4 ° C 0.787 0.786 Distillation ASTM Start of boiling 152 ° C 148 ° C 2 vol. % 159 155 5 162 159 10 167 164 20th 172 169 30th 176 173 40 180 177 50 184 182 60 I89 187 70 194 194 80
90
95
End of boiling
Residue vol. %
Loss vol. % 203
215
225
233
1.5
0.3 202
214
224
234
1.4
0 Flash point ° C
Soot point mm 42
26th 58
26th

Analysis of hydrocarbons
by adsorption with fluorescence indicator (FIA)
Aromatics Vol. # 17

Olefins 0

saturated compounds 83 sulfur content wt. y> O _4-

200

17th
0

&? 0001 (1 ppm)

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Inserts with different sulfur contents produced by mixing were, as described above, were hydrogenated in a plague bed reactor under the following conditions:

Throughput : 6 volumes of use per volume of catalyst per hour (6 v / v / h)

Pressure:

kg / cm ^£

Temperature : 3500 C

Ratio hydrogen / input : 500 liters of hydrogen at normal temperature and normal pressure for 1 liter of input.

There were six
Catalyst A:
Catalyst B:

Catalyst C:

Catalyst D:

Catalyst E:

Catalyst P:

Catalysts, namely: 0.75 wt -% platinum on alumina..

0.75 'weight -% platinum on a silica alumina carrier, which has a weight ratio of silica to alumina of 86:14.

0.75 wt -.% Platinum on a silica alumina support having a weight ratio of silica to alumina is from 12:88.

0.75 wt -.% Platinum on a silica alumina carrier which constitutes one Ge \ * - ratio of silica to alumina of 29:71 has.

0.75 wt .- ^ platinum on a silica clay carrier, which has a weight ratio of silica to alumina of 46:54.

. 0.75 wt -% platinum on a silica alumina support having a weight ratio of silica to alumina of 64: ^ 6 has.

These catalysts came in pills of 3 mm in diameter and 3 mm Shaped height.

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The table below shows the percentages that occur during hydrogenation of aromatic hydrocarbons were obtained when inserts with different sulfur contents in each case in the presence one of the six mentioned catalysts had been treated.

Sulfur content
in action
(ppm as weight
specification ) Catal
gate
A. Catal
gate
B. Kata
lysa
gate
C. Kata
lysa
gate
D. Kata
lysa
gate
E. Kata
lysa
gate
P. 1 74 % 74 % 74 % 74 % 74 % 74 % 10 68 % 71 % 68 % 68 % 69 % 70 % 25th 62 % 68 % 62 # 63 % 64 % $ 66 50 50 % 62 % 50 % 51 # 54 # 58 % 100 35 % 56 % 35 # 37 % 41 % 47 # 200 18 % 50 % 18 ^ 20 ^ 25 ^ 36 % 300 0 % 44 pounds 0 % £ - / O 10 # 25 #

The results listed in the table above clearly show the superiority of the catalyst B with regard to the Resistance to poisoning by sulfur-containing compounds. The results show in the same way that it is just not enough to include a small amount of silica in the support since Catalyst C is as bad as Catalyst A, which is none Contains silica.

The results obtained with catalysts B, D, E and F. show that from a sulfur content of between 25 and 50 ppm is, the higher conversions are obtained, the larger the silica to alumina ratio in the carrier. The influence of the silica content on the conversion is greater than the sulfur content the stake is high.

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Example 2

40 ppm of contained an insert of sulfur and which was obtained by mixing as described in Example 1 was hydrogenated with a catalyst in a Pestbett reactor of 0.75 wt -.% Of platinum on a support of silica-alumina which had a weight ratio of silica to alumina of 86:14. 35 cubic meters of feed per kilogram (100 barrels of this feed per pound) of catalyst were continuously hydrogenated under the following conditions:
Temperature : 330 ° C

Pressure : 35
Raumgesachwindigkelt : 20 v / v / h.

Hp / input: 500 liters of H at normal temperature and normal pressure per liter of liquid input.

The soot point, which can be determined quickly and easily was used to determine the degree of hydrogenation of the aromatics.

This carried out in accordance with the method of the present invention Hydrogenation was carried out on an insert which had a soot point of 26 mm, which corresponds to an aromatic content of 17 vol. $ (see Example 1), and resulted in a product which had a soot point of 30 mm, which corresponds to an aromatic content of 10% by volume.

This example shows that the process according to the invention of the hydrogenation, i.e. a hydrogenation in the presence of a catalyst which contains 0.75% by weight of platinum and whose weight ratio is Kie is selsic acid to clay in the carrier 86:14, and under the

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work is carried out under certain working conditions, can be applied continuously to a very large amount of work, without any reduction in catalytic activity and with a very significant decrease in content of aromatic hydrocarbons in use.

Example 3

It is of particular importance to create a catalyst that can withstand such uses, the sulfur content of which is random and unintentionally very high, and its activity again can be produced without having to use such a complicated process as the removal of impurities by Burning down represents.

A start was made to hydrogenate a feed with a sulfur content of 25 ppm in the presence of catalyst B from Example 1. It was at a throughput of 6 v / v / h, a pressure of 35 kg / cm, a temperature of 300 ° C and a ratio of Hp / insert of 500 1 Hp (at normal pressure and normal temperature) worked per liter of use, and a product was obtained that has a Soot point of 35 mm. To simulate the process that a ^ Insufficiently pre-treated use is unintentionally and accidentally added, a feed containing 2000 ppm of sulfur was fed to the catalyst. The catalyst was poisoned, the soot point of the product was the same as that of the starting product: 26 mm. Passing over the feed containing 2000 ppm sulfur was continued for two hours; then the feed containing 25 ppm sulfur was introduced. The soot point rose immediately and after about two hours the value was that of that originally received

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Soot point, namely 35 mm * reached.

This example shows that the catalyst is only subject to temporary poisoning.

It has also been found that the catalyst regains its initial activity very quickly when the reaction temperature is left had increased to 400 ° C over an hour, but all other conditions (pressure, space velocity, and ratio Hydrogen / input) had kept constant.

Example 4

However, treatment at a temperature of 400 ° C., at which dehydrogenation is more preferred than hydrogenation, is then useful if the original activity of the catalyst, those kept at the reaction temperature for a few hours due to the lack of use and / or hydrogen Reactor had sunk, wants to restore.

The cause of the drop in activity - under such conditions is not very clear; it could be due to an accumulation of products on the catalyst.

A feed containing 25 ppm sulfur was used in Example 1 treated conditions mentioned in the presence of the catalyst B; the soot point of the reaction product was 35 mm. After 24 hours of treatment, the feed was stopped and the reactor was maintained for 12 hours Hydrogen pressure. Then you put in again, and you was able to determine that then the soot point of the product was not

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was more than 30 mm. Thereupon the temperature was during
one hour to 40O ⁰ C, then it was increased again
its original value, namely to 300 C, is set. The reaction product had a soot point of 38 mm, which is higher
than the original value of 35mm; after 5 hours of treatment, the soot point had returned to the original value of
35 mm stabilized.

Claim

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Claims (1)

Dr. Ing. E. BERKENFELD · D i ρ I, -1 η g. H. B E R K E N F E LD, patent attorneys, Cologne System . File number ρ jij. JQ 59I. BneobevcM, ^ 1. July 1968 Sch / Nome d. Note g _>Ä> Claim Use of a catalyst containing platinum on a silica-alumina carrier to reduce the content of aromatic hydrocarbons in a petroleum distillate that passes in the range from 60 to 350 ° C and its Weight content of sulfur is a maximum of 300 ppm, by hydrogenation. 809901/0674 n (ah? ι »Ata.» Sr. ι α »