DE1645701C - Hydrocracking process - Google Patents

Description

I 645 701

The connection relates to a hydrocracking process using catalysts which release a plalin group element in a crystalline aluminosilica zeolite with a low sodium gelatin and a pore diameter of 6 to 15 Λ and a silicon dioxide. Aluminum oxide molar ratio of more than 3.0: 1 is applied or associated with it.

The use of such materials to catalyze reactions involving W ^^. Erstoff is. is known. A preferred catalyst for drowning is a material that is a platinum group metal which is combined with a zeolite Y. A hydrogen cracking process using such a. Catalyst is for example in British patent specification 995 711 described.

However, the catalysts described above are expensive materials, and one of the factors that The degree to which it regenerates successfully is what can have a major impact on its economic use can be. However, it is known that in the regeneration of zeolite catalysts including Zeolite Y catalysts pose problems. To the relative success of alternative recovery methods It is not enough to estimate the effects of these regeneration processes on the initial one Act. Has the catalyst and the initial speed to investigate the decrease in this activity in a subsequent operating period. Just as important and possibly more importantly, that the catalyst remains highly specific in relation to the desired products is and remains.

In hydrocracking tests with zeolite Y catalysts it has been found that catalysts are used in the processing of low nitrogen feedstocks have a wide range of activities (below 100 ppm) during the first few days of the experiment, which have little relationship to the relative activities of these catalysts after extended periods of operation. However, after this initial period an apparently steady state is reached in which the catalytic converters have relatively steady deactivation rates exhibit. So in order to obtain documents for valid comparisons of the catalyst performance before and after the regenerations, it is necessary to carry out tests that extend into this period of continuous deactivation, see above that attempts of a duration of at least 20 days are required.

In the course of such extensive attempts the cause of the difficulty in regeneration of Zeolite catalysts up to the period between oxidative burn-off and the start of the next Operating period tracked.

The invention accordingly relates to a hydrocarbon hydrocracking process, at the hydrocarbons at elevated temperatures and pressures in the presence of hydrogen over catalysts that from 0.01 to 10 percent by weight of a platinum group element and a zeolite with a sodium content of not more than 2 percent by weight and a pore diameter of 6 to 15 Å and a silica-alumina ratio of over 3.0: 1 exist, passed and thereby deactivated and in which one then for catalyst regeneration Hydrocarbons and hydrogen from the catalyst bed drives out the deposit on the catalysts in an inert gas-fuel stream at temperatures of at most 510 ° C burns off, residual oxygen by purging with inert gas from the catalysts drives off and reintroduces hydrogen as a precursor to restarting the reaction, the is characterized in that the catalyst bed after the oxidative burn-off and before the renewed Introducing hydrogen to a temperature below 93 C cools.

ίο If the catalyst has a temperature of about 370 to 510 "C during the burn-off and the subsequent processing ^{is to be carried out at an elevated temperature above 177 C} C, it is economically undesirable to have to cool the catalyst and then heat it up again, but it has been shown that without this cooling, the activity of the catalyst cannot be restored to the desired extent.
The temperature is preferably set to a value

ao lowered between -1 and 93 "C. This cooling can be done while an inert gas and Oxygen or just an inert gas can be passed over the catalyst so that the purge is removed of residual oxygen at a temperature below

S5 177C performed wenian can. As an inert gas for Flushing and as an inert gas, which serves as a diluent for the oxygen during oxidative burning preferably nitrogen is used. Under these circumstances you can of course start rinsing by simply cutting off the supply of oxygen.

The other stages of regeneration are carried out in accordance with normal practice. So will be upon termination one operating period the hydrocarbons

and hydrogen driven out of the catalyst bed by the supply of the feed material! ^c is stopped while hydrogen is still passed through, so that the hydrocarbons have been driven off, whereupon the hydrogen is flushed with

«O an inert gas, preferably nitrogen, is removed.

There are no adverse effects if elevated temperatures are used in this phase will.

During the various stages of regeneration including the rinse stages and the cooling period, which are the essential stage of the process according to of the invention, the following pressures can be used: The pressure during the oxidative Burning down is appropriate between Norrn?! -

r.o pressure and 70 atü. Elevated pressures are preferred from 14 to 35 atm as this reduces the time required for regeneration.

During the rinsing and cooling phases, the risk of damage to the catalyst due to the use of high pressures is lower than during the oxidative burn-off. The pressure can be between normal pressure and the process pressure used (up to 210 atmospheres). However, it is expedient to work at the same pressure as during the oxidative burning off. In general, heightened. Pressures shorten the time required for a particular phase, so these higher pressures are preferred. However, if the temperature in any phase is above the process temperature, it may be necessary for metallurgical reasons to limit the pressure in the reactor to a maximum which is below the process pressure. The gases used for the various regeneration

fiufcn are used / wake-up after lions, which lead to more than 50 V.ilimipmzeiii in tio cil Ii

liner treatment by which acidic gases such as SO., CO from 370 to 6 (K) ¹¹ C avoided. Particularly · * suitable a ¹ ·.

fiul CO. ,, are removed, and preferably also after llinsatzmaierial, a so-called Wai / hs-

finer drying in the circuit. The removal of the deslillate fraction. Wax distilleries are / was special

Acid gases can be carried out in a known manner, 5 preferred lünsai / maierialicn, but the WiTaIi

in that the gases with alkali, soda lime or another can also be used for lower-boiling oil reactions,

(first adsorbents are treated, e.g. gas oils (i.e. I ^v ractions that / u wcnig-.tci,

As mentioned above, according to the invention, 6 (J weight percent in the range of 250 to 370 C

^ cmälien cooling stage again hydrogen as preparatory boiling). The feed materials can either be direct

fiiiig for the beginning of a further operating period ία be derived from a crude oil or products from

introduced. The hydrogen can optionally represent a previous treatment, /. B. the l'ro-

Activation of the catalyst for a period of byproducts from a thermal or ka'.alj table

for example 1N to 100 hours before the renewed supply of cracking.

of feedstock. The tempera- The input materials used can be im

tLir for this activation wildly expedient to 370 to 15 essentially free of nitrogen and / or sulfur

f Hi C increased and just before re-feeding, but a distinctive feature of the Erlindimg-i-

Ucs input material reduced as required. according to the catalysts used is their relative

The zeolite has a sodium content of at most compatibility with sulfur and nitrogen

2 percent by weight. It is preferably decationized. compounds present in the input materials

This is a well-known expression that recognize are läßi ao, the compatibility ^ genüber nitrogen

that the zeolite has a deficit of meta, ication compounds especially in contrast to others

has. Another technical term for this is the term catalysts for hydrogenative cleavage, 1. B.

■ A hydrogen zeolite « used because it is assumed that catalysts that contain an amorphous silicon dioxide

that in the removal of metal cations this aluminum oxide cracking catalyst contains

be replaced by hydrogen ions. The exact 25th

Structure is uncertain. A cation deficit can The nitrogen content of a raw material for the

by analyzing the elements present in the zeolite, hydrogenative cleavage depends on the origin of the

can be easily determined. A simple method of the raw material, its boiling range and the pre-

Decationization consists in the fact that the zeolite previous treatments from which it, if necessary

treated with a solution subjected to ammonium ions . The nitrogen content can

holds, to the metal ions due to ammonium ions, however, be up to 0.3 percent by weight, and

/.u replace, whereupon the ammonium form of the zeolite substitute materials with such nitrogen percentages

is heated , whereby the ammonia is driven off if necessary processed . Preferably lies

and hydrogen ions remain. Another the nitrogen content in the range of 0.001 °. _o to

The possibility of deactivation is the treatment 35 0.15 percent by weight. The feedstock can also

with a mineral acid, ζ. B. hydrochloric acid or sulfur contain 0.01 to 5 percent by weight sulfur,

acid. The catalysts mentioned in claim 1 are

Certain metal cations, especially the metal cations, although they are over-

Group II cations, e.g. B. Magnesium, can be avengingly tolerant, but it can be beneficial to the

Zeolites are present without having the same after- 40 nitrogen content of the feedstock before the hydro-

produce partial effects such as sodium. Reduce cracking, preferably to one

if necessary, the zeolite can contain such metal cations from 0.001 to 0.003 percent by weight. Through

as a complete or partial replacement for water - the presence of nitrogen is the catalyst

contain ions. sator is not poisoned in the way it is with others

The preferred zeolite is Y.45 zeolite hydrogen cracking catalysts

As the hydrogenation metal are one or more metals that would be, however, the performance of the platinum group catalyst will be present. These metals are first deteriorated to a certain extent, even if they are deposited by ion exchange, so that they do not form part of the zeolite to the extent that the process becomes impracticable, and not only on these. In certain cases the advantages of the zeolite predominate higher are upset. If the zeolite is cationized by a method 50 catalyst performance in the treatment of feed using ammonium exchange materials with reduced nitrogen content, the metal is preferably added to the ammonium exchange at additional costs caused by the previous nitrogen exchange. Preferred are distance incurred.

Palladium and platinum. These metals are in a When the nitrogen content of the feed is in

Amount of 0.01 to 10 percent by weight, in particular 55 of a pretreatment stage , can be reduced

present from 0.1 to 5 percent by weight. this is done by catalytic hydrogenation. When

Zeolite crystals contain water molecules that can be removed by catalysts, one or more hydration heaters without destroying the crystal structure, metals or their compounds from groups VI a can be removed. In order to avoid the undesired removal and VIII of the Periodic Table * on acidic water during processing. Molybdenum together are suitable as metals, the Zsolite is at the beginning preferably in pre-anhydrous form with one or more iron group metals. preferably 5 to 40 ⁰ / "molybdenum, calculated as the

Hydrocracking can be used Trioxyd MoO ₃ , and 1 to 15 ° / "iron group metals,

in order to manufacture a product that is mainly calculated as divalent oxides (e.g. CoO or NiO),

Gasoline range is boiling. 63 A known cracking catalyst can be used as the acidic carrier Petroleum torches will preferably be used as input materials. For example, are suitable

fractions that contain more than 50 percent by volume of material catalysts from 50 to 95 percent by weight silicon

contain that ^{boils over 2GO 0} C, in particular fracdioxide and 5 to 50 percent by weight of aluminum oxide

or carriers with more than 50 percent by weight of aluminum oxide and less than 50 percent by weight of an acidic oxide of elements from groups II. III and IV of the periodic table, e.g. B. Oxides of Hör, silicon. Titanium or zircon. For example, the following combinations are suitable as catalysts:

Ni (as NiO) 0 to 5 weight percent

Co (as CoO) 0 to 5 percent by weight

Mo (as MoO ₃ ) ... 5 to 20 percent by weight B ₂ O ₃ 15 to 25 percent by weight

Al ₄ O ₃

rest

Ni (as NiO) O to 5 percent by weight

Co (as CoO) 0 to 5 percent by weight

Mo (as MoO ₃ ) ... 5 to 20 percent by weight SiO ₂ 50 to 95 percent by weight

AI ₂ O ₃ remainder

The nitrogen removal can be carried out under the following conditions:

Temperature 343 to 454 "C

Pressure 105 to 175 atm

Room flow velocity .... 0.4 to 3.0 V / V / hour.

Gas cycle 900 to 2700 Nm ³ / m ^s

Treatment of the circulating gas NH ₃ removal

In a two-stage process of the type described above, the product from the nitrogen removal stage is preferably debutanized or topped to 82 "C. Before it is introduced into the second stage, the hydrocracking stage. The recycle gas is subjected to a treatment to remove ammonia. In the second stage For example, the cycle gas is re-subjected to ammonia removal treatment, the liquid product can be fractionated and undesired heavy material can, if necessary, be recycled to the hydrocracking stage until it disappears.

The process conditions for the hydrogenative cracking can be selected from the following ranges:

temperature

pressure

Space velocity

Amount of hydrogen supplied

232 to 510 C, preferably 266 to 455 "C, in particular 288 to 399 ° C in a two-stage process

17.5 to 210 atm. preferably 105 to 175 atm

0.2 to 5.0V V, Std .. to be required 0.4 to 2.0 V / V / h

180 to 3600 Nm ³ , m ³ . preferably 900 to 2700 Nm ³ m ³ total proportion of products which boil below 177 ° C, based on the weight of the feed material. is hereinafter referred to as conversion and the weight proportion of gasoline (C ₅ to 177 ^° C) in the system total gas plus gasoline as selectivity, respectively. the total weight of the fraction boiling in the range 82-177 C ^r divided by the total weight of the fraction boiling from C, to 82 ⁰ C when the petrol ratio is hereinafter referred to. Preferably

ίο the conversion at least 50 percent by weight. The height the conversion can be adjusted according to known principles by changing the working conditions. For example, the conversion by increasing the temperature and / or by lowering the room

ts flow rate increased. With sales in of this order of magnitude, selectivities of at least 75% and gasoline ratios of at least 1.5 are obtained. The conversion per pass is preferably in

ίο Maintained range from 60 to 70 percent by weight. The

Product will be at an intersection between 150 and

200 C fractionated, and the higher-boiling fraction is circulated.

If the ratio of fresh input to total

is used in such a cycle process kept the same value as the turnover per pass the total conversion is 100 percent by weight.

This conversion is preferred. Maintaining the urine rate per pass

can be achieved by increasing the temperature as the operating time progresses. This need to increase the temperature is evidence of a gradual deactivation of the catalyst.

It has been found that it is possible with the regeneration process of the present invention. to bring the performance of a used catalyst (calculated as activity, specificity and stability) almost back to the level of a fresh catalyst.

example 1

A catalyst made from palladium on dekationi y zeolite, had the following composition:

Palladium 0.52 percent by weight

Aluminum 13.4 percent by weight

Silicon 33.1 percent by weight

Sodium 0.94 percent by weight

Surface 676 m ² g

In the process according to the invention it is possible to achieve high yields of fractions in the gasoline boiling range (C ₅ to 177 C) with low yields of so-called middle distillates and gas. It is also npical for the method according to the invention. that it gives low yields of fractions in the boiling range from X2 to 1 "7 C in relation to the yields of the oil in the SicdcberiMch from C ₅ to 82 C. The

The catalyst was for the hydrogenating Kr.ik

kung a petroleum fraction used, which had a boiling range from 177 to 541 ⁼ C, and 0.0025 weight; percent nitrogen and 0.011 weight percent Schwt fei. The cracking was carried out under the following conditions, which were kept constant throughout the experiment:

Pressure 105 atm

Room flow velocity 1.0 V V hrs.

Gas cycle 1800 Nm ³ in ³

Make-up gas hydrogen

Sales to material that

boiled below 177 "C .. 65 weight percent

That was cowardly for all catalyst tests Standard procedure applied:

The Salzmaterwl was a catalyst

temperature of 204 C with circulation of the hydrogen at a pressure of 105 atü passed over the catalyst. The catalyst temperature was then increased at hourly thereafter 28 ⁰ C to 260 ° C and twelve times in AV'jtänden of one hour at each 5.5 ° C, was until the required conversion is achieved. Thereafter, the temperature was increased only as required to maintain the conversion.

In the first operating period when using an oil-based catalyst, the required conversion ■ level was reached after 190 hours at a temperature of p32 ° C. Then the temperature was Hoof increased in the manner shown in Fig. (A). The • appropriate changes in selectivity and Gasoline ratio are shown in Fig. (B) and (c).

The partially deactivated catalyst was then subjected to the sequence of actions described below regenerated:

1. The feed supply has been interrupted. Hydrogen was at the final temperature of the experiment and a pressure of 105 atü for 12 hours in the circuit.

2. The hydrogen supply was then cut off and the pressure was reduced to normal pressure, whereupon dr imal was purged with nitrogen by sequentially the pressure was increased to 7 atmospheres and then released to normal pressure.

3. With the circulation of nitrogen at 1000 V / V catalyst / hour (measured under normal conditions) started at 17.5 atmospheres and 371 ° C.

4. Oxygen was continuously added to the nitrogen introduced to burn off the debris. The temperature was controlled by the amount of the blown oxygen was kept at 454 ° C.

5. After the deposits have burned off in the manner described under 4. and the Oxygen in the nitrogen cycle had risen to over 10 percent by volume, the temperature was increased to 510 "C and continued circulation of nitrogen and oxygen for an additional 6 hours. The pressure was 17.5 atmospheres.

6. The temperature was lowered to ambient temperature (16C) while the circulation of Nitrogen and oxygen was continued. Pressure 17.5 atm.

1F. The pressure was then released to normal pressure and the catalyst is purged with nitrogen by alternating three times at ambient temperature Nitrogen was injected to 7 atmospheres and then released again to normal pressure.

f. The catalyst was then purged with hydrogen, by alternately pushing hydrogen up to 7 atmospheres three times at ambient temperature and then was released back to normal pressure.

9. After pressing to 105 atmospheres with hydrogen at ambient temperature, the temperature was increased to 204 ° C. while hydrogen was circulated at 105 atmospheres.
10. Feed was reintroduced at 204 "C and the new operating period started under the above conditions.

The desired conversion was reached after 230 hours at a temperature of 331 ° C. and again maintained by increasing d (r temperature, as shown for the second operating period in Fig. (a). The corresponding changes in the selectivity and the gasoline ratio are shown in Fig. (B) and (c) shown.

A comparison of the first and second periods of operation reveals a practically complete restoration of the initial activity of the catalyst (defined here as the catalyst temperature after 240 hours), but there is a decrease in activity of around H ⁰ C after regeneration during the longer period of operation (720 hours). Despite this decrease in activity during the long operating period, the product distribution, defined by the selectivity and the gasoline ratio, was at all times comparable with the product distribution that was achieved with the fresh catalyst.

In a comparative test under similar conditions of hydrogenative cracking, the partial

ao wise deactivated catalyst after the second Period of operation regenerated in the same way as described above, but with the temperature was not lowered to ambient temperature after oxidative burning (level 5). Instead of this

»5 became the following after oxidative burning off Measures carried out:

11. The temperature was lowered to 204 ° C while nitrogen and oxygen continued to be bubbled through. Dn Λ 17.5 atm.

12. The pressure was reduced to normal pressure and the catalyst was flushed with nitrogen by adding three times at 204 X alternately with nitrogen up to 7 atmospheres and relaxed to normal pressure would.

13. The catalyst was then purged with hydrogen, by alternately pushing hydrogen up to 7 atmospheres three times at 204'C and then applying it was relaxed to normal pressure.

14. The pressure was then increased to 105 atmospheres and with the circulation of hydrogen at 204 "C began.

15. Feed was reintroduced at 204 ° C and the operation below the above Conditions approached again.

In this case, the desired conversion was achieved after 240 hours at a temperature of 363 ° C and maintained again by increasing the temperature, as in Fig. (a), third operating period.

shown. During this period of operation, activity resulted in a decrease in activity of 31 "C versus the initial activity a considerable deterioration the selectivity and the gasoline ratio [Fig. (b) and (c)] compared to the first and second Operating period. The increasing deviation of the subsequent selectivity and the subsequent Gasoline ratio illustrated by the values during the first and second operating periods continue the failure of this third operating period was achieved.

Example 2

The partially deactivated catalyst was used for the third operating period described in Example 1 regenerated again using measures I to 5 and 11 to 15. A fourth operating period was started under the conditions mentioned in Example I.

209 616/180

In this case, the required conversion was first after about 270 hours at a temperature of 370 ° C reached [Fig. (a)]. This represents another Activity decrease by 3.3 ° C compared to the third operating period d «r. Given this further decrease in activity, the insignificant improvement in Selectivity [Fig. (b)] and only a slight improvement in the gasoline ratio [Fig. (c)] this attempt did not continue

The partially deactivated catalyst from the fourth operating period was regenerated again, but this time in the manner described in Example 1, stages 1 to 10. A fifth operating period was then started. In this case, after increasing the temperature at the usual rate, the required conversion was first achieved after 170 hours at a temperature of 331 ° C. and then maintained by increasing the temperature, as for the fifth operating period in FIG . (a) Despite this obvious *> increase in the initial activity compared to the first operating period, the activity after 240 hours was about 9 ° C worse than during the first and second operating periods, but about 22 "C better from the third and second fourth operating period. After "5 of the 720th hour, the activity was about 30 ⁰ C lower than in the first operation period and around 19 ° C lower than in the second operating period. in parallel to the occurring in the fifth operation period improvement in the initial activity increased the initial values the selectivity and the gasoline ratio [Figs. (b) and (c)] and approached the values obtained in the first and second operating periods were obtained. The values of selectivity and des Petrol ratio for the longer running time (720 hours) in the fifth operating period indicate that they were lower than the values for the first two operating periods, but a far-reaching one Restoration of performance had been achieved by this regeneration process.

Claims (1)

Claim: Hydrocarbon - hydrocracking process in which hydrocarbons are used at elevated temperatures and pressures in the presence of hydrogen on catalysts composed of 0.01 to 10 percent by weight of a platinum group element and a Zeolite with a sodium content of not less than 2 percent by weight and a pore diameter of 6 to 15 Å and a silicon dioxide-aluminum oxide ratio of over 3.0: 1 are passed and thereby deactivated and in which one then for the catalyst regeneration hydrocarbons and hydrogen from the Catalyst bed drives out the deposit on the catalysts in an inert gas-oxygen stream burns off at temperatures not exceeding 510 ° C, residual oxygen by purging with inert gas drives off the catalysts and re-generates hydrogen in preparation for restarting the Introduces reaction, characterized in that the catalyst bed after oxidative burning and before the renewed introduction of hydrogen to temperatures below 93 ° C cools 1 sheet of drawings