DE1645747B2 - PROCESS FOR SELECTIVE HYDROGENATION OF PYROLYSIS PETROL - 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 total reaction 60 mm, in particular 40 to 60 mm. As pipe lengths room in the trickle phase with essentially »5, 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. Same-

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 ♦ <> however, the hydrogen-containing fraction should expediently at least be inert gases in addition to 100 ° C. in the presence of noble metal catalysts on aluminum oxide supports, which are marked by 50% by volume, if possible over 70% by volume> Hydrogen net is that the aluminum oxide contains cobalt, magne-. It is advisable to use hydrogen pressures between Lithium or zinc wholly or at least 20 and 80 atmospheres, advantageously 30 to 60 atmospheres at-20% has been converted into spinel. 45 turn. You can z. B. work in such a way that the

In this mode of operation, the temperature of the incoming pyrolysis gasoline 20 to 30 ° C contained in the feed materialier is primarily unstable, and that the temperature of the feed material hydrogenated predominantly diolefinic compounds, while in the first part of the reaction space, ie 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. In the second part of the reaction space, the hydrogenation products then have a diene content, an increase in temperature to 150 to 250 ° C. below 1% by weight and bromine numbers between 20, depending on the type of feed. The temperature regulation can be and 55 g / 100 g. Carry out in such a way that the reactor tubes

Hydrogenation products of this type meet the requirement with heat-transferring means surrounding them, which over These were usually found in two or more chambers along 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 emerges 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 v / eise 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 the 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 Miniumoxidträgern, whereby the aluminum oxide with now also the monoolefins was largely hydrogenated who-cobalt. Magnesium, lithium or zinc in its entirety or the, The hourly throughput of pyrolysis gas

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 catalystvohimina in the two parts are based on the specified loads. You can use 0.2 to 2 times the volume of the already hydrogenated or partially hydrogenated product from the separators to the top of the reactor or reactors return and mix there with the insert, the return expediently without Pressure relief is made.

The amount of hydrogen to be used is selected in generally so that it is 10 to 30% higher than the amount of hydrogen obtained from the pyrolysis gasoline in chemical. Bond is recorded. »5

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 below 1% by weight, mostly below 0.1% by weight.

The gum values before and after aging are below 5 rag / 100 ml, and the induction time is above 240 minutes. The bromine number is generally 1 to 12 g / 100 g. The octane numbers of the Hydrogenation products added to 0.04% by volume of tetraethyl lead (TEL) are approximately at the same level such as the corresponding octane numbers of the feedstock. This way of working is thus achieved been that the monoolefins can largely be hydrogenated without the knocking behavior of the lead To change gasoline significantly. In the procedure outlined, there is a certain decomposition of the organic sulfur compounds contained in the feed. The oil content of the hydrogenation products is generally 10 to 80% of the sulfur content of the feedstocks. One recognises so that in addition to the advantages of mono-olefin removal, there are also a considerable number of noteworthy benefits Desulfurization of the feed material causes what also improves lead sensitivity of the hydrogenation product contributes to the feedstock. It is noteworthy that despite this education of hydrogen sulfide, the catalyst retains perfect hydrogenation activity. In months Ongoing tests have found that the catalysts mentioned have an extremely constant Have hydrogenation activity.

Deployed
Cracked gasoline
from a
mild spal
tendency crack
system Hydrogenation
product,
Average
evaluate
1000 operating
hours Deployed
Cracked gasoline
from a
sharp spal
tendency crack
system Hydrogenation
product,
Average
evaluate
900 operating
hours Benzene toluene
Faction one
Short term
Cracked gasoline
mission Hydrogenation
product,
Average
evaluate
1000 operating
hours colour
odor deep yellow
unpleasant colorless
enjoyable
aromatic deep yellow
unpleasant colorless
enjoyable
aromatic colorless
unpleasant colorless
enjoyable
aromatic Density at 20 ° C 0.775 0.768 0.823 0.817 0.858 0.853 Bromine number (g / 100 g) 65 7th 73 5 40 3 Monoolefin content
(Wt .-%) - approx 4 - approx. 3 - approx. 2 Diene content
(O / o by weight) 18.0 0 23.8 0 13.1 0 Gum from aging
(mg / 100 ml) 1 1 2 2 2 2 Gum after aging
(mg / 100 ml) 5,300 1 8.240 2 6.055 2 Induction time (min) 130 240 90 240 20th 240 RON unleaded 97.0 93.5 100.0 101.2 - - RON + 0.04% by volume
TEL 101.0 99.5 100.5 102.0 - - MOZ unleaded 85.0 82.9 87.0 87.3 - - MOZ + 0.04% by volume
TEL 88.8 89.1 89.0 89.7 - - Benzene (wt .-%) 25.2 25.1 43.2 43.0 53.8 53.7 Toluene (wt%) 16.8 16.8 17.4 17.4 23.8 23.9 Sulfur (wt%) 0.011 0.007 0.01 0.002 0.015 0.002

example

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

To produce the catalyst, the support was impregnated with a solution of palladium (H) chloride. That 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 wt%.

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. That

ίο liquid product trickled into 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 section of the reactor, the Temperature rose to almost 230 ° C and was 220 ° C at the reactor outlet.

A comparison of the properties of two distilled pyrolysis petrol from mild

ao and sharp cracking cracking plants with those of the hydrogenation products obtained therefrom are the above Tabel. 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 Vo have been converted into spinel. Claims: According to Patent 15 45 297, it has now been found that particularly beneficial results are obtained when h Modification of the process for selective hydrogenation treatment at temperatures hydrogenation of pyrolysis gasoline or fractions 5 below 100.degree. C., followed by such hydrogenation at temperatures below ^100.degree. C. from 150 to 250.degree. Presence of noble metal catalysts atif aluminum For the process according to the invention, two Miniumoxidträgem, whereby the aluminum oxide in the hydrogenation stages - below and above 100 C - the noble metal catalyst, which is exactly the same as cobalt, magnesium, lithium or zinc, are used on spinel supports or at least 20% are converted into spinel. According to patent 1545 297, it has been found to be an expedient procedure to treat the hydrogenating treatment at temperatures above 100.degree. C. of the hydrogenating treatment at temperatures below 100.degree. 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 reactor 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 100 ° C, the feed material trickles into the liquid directly in the same reactor at the same pressure ao phase through vertical tubes over the solid in the Reucid using the same catalyst reaction space arranged catalyst down. as closes. Prove the tubes for accommodating the catalytic converter