DE1645747C3 - Process for the selective hydrogenation of pyrolysis gasoline - Google Patents

Description

3. The method according to claim 1 and 2, characterized, for. B. those with clearances from 25 to characterized in that in the entire reaction 60 mm, in particular 40 to 60 mm. As pipe lengths room in the trickle phase with essentially 95, those of 3 to 8 m are suitable.

dormant hydrogen atmosphere works. It is often advantageous to use the two reaction zones

4. The method according to claim 1 to 3, characterized to be provided in a single reactor bundle. It is characterized that in the hydrogenation of the Pyro- but also possible in two or more hinlysebenzins to work up to 2 parts by weight of hydrogenation interconnected reactors and per 1 part by weight of fresh feedstock 30, the product of one zone on the top of the returned to the inlet of the hydrogenation reactor to abandon the hydrogenation reactor of the next zone. Around will. an even distribution of the products also in

to reach the downstream reactors is recommended

is it not necessary to follow the previous hydrogenation

35 reactor to separate gas and liquid in a separator and both separately from each other to be fed to the next reactor. Equal-

The subject matter of the patent 15 45 297 is a process where hydrogen is added from above. It is for selective hydrogenation of pyrolysis gasoline or not necessary to use pure hydrogen, Fractions from it at temperatures below 40, however, should the hydrogen-containing fraction as well Expediently at least 100 ° C in the presence of noble metal catalysts inert gases on aluminum oxide carriers, which are marked by this: 50% by volume, if possible over 70% by volume, hydrogen What is net is that the aluminum oxide contains cobalt, magne-. It is advisable to keep hydrogen pressures between »Ium, lithium or zinc completely or at least 20 and 80 atmospheres, advantageously 30 to 60 atmospheres at-20% has been converted into spinel 45. You can z. B. work in such a way that the

With this method of operation, the temperature of the incoming pyrolysis gasoline is primarily 20 to 30 ° C unstable contained in the feedstocks, pre- is, and that the temperature of the feedstock predominantly hydrogenated diolefinic compounds, while in the first part of the reaction space, d. H. in the part rend the hydrogenation of the monoolefins only in lower than the diolefin hydrogenation, does not exceed 100 ° C, takes place in an orderly manner. So, depending on the type of 50 In the second part of the reaction space is then Feedstock the hydrogenation products a diene an increase in temperature to 150 to 250 ° C content below 1 wt .-% and bromine numbers between 20 made. You can regulate the temperature and 55 g / 100 g. Perform in such a way that you can see the reactor tubes

Hydrogenation products of this type meet the requirement with heat-transferring means surrounding them, which over wrestling, which usually occurred in two or more chambers on autobenzmkomponen- 55 the length of the reactor be asked. It occurs but in recent times are distributed. As a heat transfer medium is suitable strengthens the desire, as a car gasoline compo- for example water, which one through the chimney - Made from pyrolysis gasoline - such mern and an external heat source, z. B. a To use products in which the monoole heat exchanger is also in circulation. With this fine are largely hydrated. It is here of course 60 arrangement that it is possible to effect that, for example, that the removal of the monoolefins in the first part of the reactor, the temperature of the easily done. Reactant remains below 75 to 100 ° C,

In further processing of the procedure for selective d. H. below the temperature at which the unstable tive hydrogenation of pyrolysis gasoline or fraction compounds polymerize, and that only after Hynen from it at temperatures below 100 ° C in 65 dration of this unstable, predominantly diolefinic Presence of noble metal catalysts on aluminum compounds, the temperature is increased so that aluminum oxide carriers, whereby the aluminum oxide is largely hydrogenated with the monoolefins-cobalt, Magnesium, lithium or zinc whole or the. The hourly throughput of pyrolysis gasoline

carries 2 to 10 in the first part of the hydrogenation, advantageous 5 to 7.5 kg / liter of catalyst volume, in the second part 1 to 5, advantageously 2 to 3 kg / liter.

The catalyst volumes in the two parts are based on the specified loads. Man can be 0.2 to 2 times the volume of the already hydrogenated or partially hydrogenated product from the separators return to the top of the reactor or reactors and add to the insert there, the recirculation is expediently carried out without pressure relief.

The amount of hydrogen to be used is generally chosen so that it is 10 to 30% higher than the amount of hydrogen that is chemically bonded to the pyrolysis gasoline.

In a separator connected downstream of the reaction chamber, a separation between the carry out liquid and gaseous products and release such amounts of gas from the gas space, that the desired excess hydrogen is withdrawn here. The extent to which the The reaction product behind the reaction space is guided by the requirements of the stabilization of the liquid hydrogenation product in a downstream stabilizing column.

The hydrogenation products have a diene content less than 1 wt .-%, usually 0.1 wt unterhab ⁰ / ". The gum levels before and after aging are below 5 mg / 100 ml, and the induction time is over 240 minutes. The bromine number is generally 1 to 12 g / 100 g. The octane numbers of the hydrogenation products to which 0.04 vol. Vol. With this way of working it has thus been achieved that the monoolefins are largely hy-

can drier without the knocking behavior of the leaded To change gasoline significantly. In the procedure outlined, there is a certain decomposition of the organic sulfur compounds contained in the feed one. The sulfur content of the hydrogenation

is products is generally 10 to 80% of the Sulfur content of the feedstock. So you can see that in addition to the advantages of the monoolefin removal also causes considerable, noteworthy desulphurisation of the feedstock,

ao what also improves the lead sensitivity of the hydrogenation product compared to the feedstock contributes. It is noteworthy that, despite this formation of hydrogen sulfide, the catalyst is a maintains perfect hydrogenation activity. In months

* 5 ongoing trials have found that the mentioned catalysts have an extremely constant hydrogenation activity.

Deployed Hydrogenation Deployed Hydrogenation Benzene toluene Hydrogenation Cracked gasoline product, Cracked gasoline product, Faction one product, from a Average from a Average Short term Average fashion spal evaluate sharp spal values Cracked gasoline evaluate tendency crack 1000 operating tendency crack 900 operating 1000 operating factory hours factory hours mission hours

color
odor

Density at 20 ° C
Bromine number (g / 100 g)

Monoolefin content
(Wt .-%)

Diene content
(Wt .-%)

Gum from aging
(mg / 100 ml)

Gum after aging
(mg / 100 ml)

Induction time (min)
RON unleaded

RON + 0.04% by volume
TEL

MOZ unleaded

MON +0.04 vol .- * / o
TEL

Benzene (wt%)
Toluene (wt%)
Sulfur (wt .- * / o)

deep yellow colorless

unpleasantly pleasant aromatic

0.775 0.768

65 7

- approx. 4

18.0 0

1 1

5,300 1

130
97.0
101.0

85.0
88.8

25.2
16.8
0.011

240
93.5
99.5

82.9
89.1

25.1
16.8
0.007

deep yellow colorless

unpleasantly pleasant aromatic

0.823 73

23.8
2
8.240

43.2
17.4
0.01

0.817
5
approx. 3

240

101.2

102.0

87.3
89.7

43.0
17.4
0.002

colorless colorless

unpleasantly pleasant aromatic

0.858
40

13.1

6.055
20th

53.8
23.8
0.015

0.853
3
approx. 2

240

53.7
23.9
0.002

example

To produce the catalyst support, spheres with a diameter of 3 to 5 mm made of active aluminum oxide with an internal surface area of 288 m ⁹ / g were soaked at ordinary temperature with a solution of lithium formate and dried at 150 ° C. The support was then dried at 1050 ° C. for 6 hours Annealed The finished support contained 0.93% by weight lithium and consisted of 75% lithium aluminum spinel and 25% α-aluminum oxide. The inner surface area was 46 m ² / g, the mean pore size 700 A.

To produce the catalyst, the support was impregnated with a solution of palladium (II) chloride. The palladium salt was reduced to the palladium with an alkaline, 30% strength aqueous formaldehyde solution. The catalyst was then washed free of chlorine and dried. The palladium content of the finished catalyst was 0.6 % by weight. ao

The catalyst was in an amount of 1.6 liters in a vertical tube of 24 mm inner diameter and 4 m length introduced, in which above feed material and hydrogen were fed. The two halves of the reactor tube were separated from one another with water heated

The hydrogenation of the pyrolysis gasoline was carried out in a hydrogen atmosphere of 50 atm. The product to be hydrogenated, which has previously been distilled and with 40 ppm di-tert-butylphenol as an inhibitor Was added, along with the hydrogen at the top of the reactor at 25 ° C with a load of 2 kg / liter and hour introduced. The liquid product trickled in the hydrogen atmosphere down over the catalyst. The temperature of the heating water was in the upper half of the reactor 75 ° C. and 220 ° C. in the lower section. A temperature profile of 30 was established in the upper reactor section up to 80 ° C; in the lower reactor section the temperature rose to almost 230 ° C. and was on Reactor outlet 220 ° C.

A comparison of the properties of two distilled pyrolysis petrol from mild and sharp cracking cracking plants with those of the hydrogenation products obtained therefrom are the above Table. Also included are results obtained during hydrogenation under the same conditions were obtained when using a benzene / toluene fraction from pyrolysis gasoline.

Claims (2)

at least 20% has been converted into spinel. Patent claims: According to patent 15 45 297, it has now been found that particularly advantageous results are obtained if one is particularly careful 1. modification of the process for the selective maa the hydrogenating treatment at temperatures hydrogenation of Pyroly: ^ gasoline or fractions 5 below 100 ° C such connects at temperatures thereof at temperatures below 100 ⁰ C in 150 to 250 ° C. Presence of noble metal catalysts on aluminum For the process according to the invention, in both iainiumoxidträgern, the aluminum oxide the hydrogenation stages - below and above 100 C - the with cobalt, magnesium, lithium or zinc the very same noble metal catalyst on spinel supports or at least 20% can be converted into spinel. As a convenient way of working has been, according to patent 1545297, thereby it has been proven to be the hydrogenating treatment characterized in that the hydrogenating temperatures above 100 ° C of the hydrogenating conditions Treatment at temperatures below treatment below 100 ° C immediately in the same 100 ° C to connect such a reactor at temperatures of 150 and at the same pressure, up to 250 ° C. 15 It is advantageous to work in the entire reaction 2. The method according to claim 1, characterized in that there is essentially space in the trickle phase indicates that one is the hydrating hand-resting hydrogen atmosphere. treatment at temperatures above 100 ° C of the hy- To remove the unstable (diolefinic) During treatment below J00 ° C, the feed material trickles into the liquid directly in the same reactor at the same pressure ao phase through vertical pipes over the firmly in the re- and using the same catalyst reaction space arranged catalyst down. When closes. Prove the tubes for accommodating the catalytic converter