DE2517869A1 - PROCESS FOR DECOMMISSIONING A CATALYST-FILLED REACTOR FOR THE CATALYTIC HYDRATION OF A LIQUID OR GASEOUS FEED - Google Patents

Description

SHELL INTERNATIONAL RESEARCH MAÄTSCIIAPPIJ B.V. The Hague, Netherlands

"Procedure for decommissioning a catalyst-filled Reactor for the catalytic hydrogenation of a liquid or gaseous feed ".

Priority: April 25, 1974, the Netherlands, No. 7405565 and February 27, 1975, the Netherlands, no.7502315

The invention relates to a method for shutting down a catalyst-filled reactor for the catalytic Hydrogenation of a liquid or gaseous feed by passing the feed over the catalyst in the presence of added hydrogen. Such a hydrogenation is usually carried out at temperatures above 300.degree. In many In some cases, the feed contains sulfur-containing compounds from which hydrogen sulfide is formed during hydrogenation.

The aforementioned catalytic hydrogenation is often used in the refinery

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kidneys of mineral oil, but also in other areas of application.

An example of the use of a liquid feed for catalytic purposes Hydrogenation represents the catalytic desulfurization of certain Petroleum fractions, such as distillate or residue fractions. In this process, the feed is combined passed with hydrogen through a reactor filled with the desulfurization catalyst at a temperature at which the Feed is not yet converted or only slightly converted by cleavage or isomerization. The ones in the liquid feed The sulfur compounds contained are hydrogenated with the formation of hydrogen sulfide. One receives as products on the one hand the desulphurized feed and, on the other hand, a gas containing hydrogen sulphide and unreacted hydrogen, which from The latter gas can, for example, be transferred to a Claus plant described below.

An example of the aforementioned catalytic hydrogenation using a gaseous feed is the catalytic reduction of a Claus exhaust gas from a Claus plant for production of elemental sulfur by reacting sulfur dioxide and hydrogen sulfide. The Claus exhaust gas contains another certain percentage of unreacted sulfur compounds that usually have to be removed, which is done by reduction of all sulfur compounds can be achieved with hydrogen to hydrogen sulfide and after which the hydrogen sulfide formed separated from the Claus exhaust gas (e.g. by absorption) and sent to the Claus

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Plant is returned. Claus plants are not only found in refineries, but also - for processing the gas that has been separated from the natural gas Hydrogen sulfide - in natural gas fields.

Almost inevitable in catalytic hydrogenation A phenomenon that occurs with sulfur compounds is the deposition of carbon on the catalyst. This carbon often comes either from the hydrocarbons in the feed (e.g. in the desulfurization of petroleum fractions) or from the Heating admixed combustion gases {e.g. in the reduction of Claus exhaust gas). When desulphurising liquid products tar-like products, for example, are also deposited on the catalyst.

Solid particles such as slag, silica, metal salts and ~ Iron particles, are usually found at the beginning of the catalyst bed deposited while the sulfides and carbon are present the full length of the catalyst bed.

When this catalyst is regenerated, the carbon and

will

the tarry products burned off, and thereby / to maintain an acceptable temperature in the reactor is in any case sufficient with large amounts of steam or nitrogen mixed amount of oxygen fed in. In practice it will be common Temperatures of 300 to 500 C are used because the carbon is not burned off at lower temperatures. In this regeneration the sulphides become simultaneously with the carbon and

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the tar is oxidized, being careful because of the desired limited heat This oxidation can only be carried out very much. Regeneration accordingly usually requires a very long time, which can be up to a few days in the case of large reactors.

In some cases, e.g. in the desulphurisation of petroleum residue fractions, the reactor contains very large amounts of catalyst, e.g. 500 tons. In this case, the amount of catalyst on which no solid particles are deposited, absolutely very large compared to the amount of catalyst on which such Particles have been deposited. This leads to the disadvantage that when the carbon and tarry products are burned off the metal sulfides of the total amount of catalyst are oxidized.

If the reactor has to be opened for certain reasons, it is not sufficient, as expected, to cool the reactor down and purge it with an inert gas. It was found that when opened of the reactor after long flushing with an inert gas of low temperature, the catalyst begins to glow in the air and, if the feed contained sulfur compounds, releases sulfur dioxide. Under these conditions the catalyst exhibits accordingly has pyrophoric properties and carrying out work on or in the reactor is accordingly impossible or dangerous.

So far, this problem has been resolved by completely regenerating the

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Catalyst dissolved before opening the reactor. This solution is however, costly and time consuming. The aim of the present invention is therefore to find a different approach.

In practice it happens, for example, that a reactor has to be opened, although the activity of the catalyst has not yet decreased so far has that regeneration is required. Another object of the present invention is therefore to provide a method to be made available, in which in these cases no regular

in which

regeneration is required and / he reactor can be opened anyway can.

It was found that the pyrophoric properties of the catalyst by means of a fully controlled oxidation in which the temperature is continuously below by means of suitable measures 300 ° C can be completely eliminated.

Surprisingly, this "passivation" of the catalyst can be achieved without simultaneously oxidizing the active sulfides such as cobalt, nickel, molybdenum and / or tungsten sulfide. The time required for passivation is therefore considerably less than for conventional regeneration treatments, in which the active sulfides are oxidized.

It was also found that the carbon and the tarry Products are hardly or not at all oxidized during passivation. There is certain evidence that the pyropho-

^ nQRAR / Π719

Renal properties of the catalyst are due to the presence of finely divided iron and / or iron sulfide, which (the) is (are) oxidized at low temperatures.

The invention accordingly relates to a method for decommissioning a reactor filled with catalyst for the catalytic hydrogenation of a liquid or gaseous feed by passing the feed over the catalyst in the presence of added hydrogen, which is characterized in that

(a) the temperature in the reactor, if it is more than 300 C

such carries, reduced to below 300 C and a / lower

Temperature is maintained until the reactor is opened;

(b) the supply of the feed interrupted and the added hydrogen during or after the reduction in the Temperature according to (a) is replaced by an inert gas;

(c) the reactor for some time with one of those mentioned under (b)

Inert gas existing purge gas is purged;

oxygen

(d) then such an amount of / containing gas

is added to the purge gas that the initial oxygen content of the purge gas is at most 1 percent by volume;

(e) the oxygen content of the purge gas is increased and the purge gas feed is continued until there is practically no more heat generation in the reactor;

(f) the oxygen partial pressure of the purge gas to at least 0.2

kg / cm is increased;

(g) the reactor is opened.

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Since the catalytic hydrogenation is generally carried out at temperatures above 300 ° C in the reactor, the temperature in the reactor, in most cases must be lowered by cooling to below 300 ⁰ C.

If the feeding of the feed before the lowering of the temperature is interrupted in the reactor, it is possible to adjust the temperature by means of the supplied hydrogen or by means of the purge gas to belittle. In particular, when a heavy feed such as a petroleum residue fraction has been hydrogenated, it is advisable to interrupt the supply of the feed at high temperatures in order to prevent the feed from solidifying in the reactor.

If a liquid feed has been processed, it is possible immediately before the reactor is shut down to another, lighter feed, such as heavy fuel or gas oil, pass over and lower the temperature in the reactor by adding this light feed. This represents one preferably Embodiment. In this way, any remaining residues of the residue product are removed may have deposited on the catalyst particles. A liquid also leads to faster cooling of the Catalyst as a gas.

It is also possible to reduce the temperature in the reactor during or partially during the interruption of the feed decrease, the interruption of the feed gradually

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takes place and accordingly takes a longer time. The simultaneous cooling and interruption of the feed is e.g. carried out when hydrogen is fed to the reactor and then the feed of the feed is gradually interrupted or if a colder feed is then initiated will.

The supply of the feed can also be interrupted after cooling , whereby the cooling can be brought about at least partially by means of the feed «In this case, natural only a small part of the feed is hydrogenated, so that under certain conditions it may be advisable during cooling can use a feed that does not need to be hydrogenated.

Preferably the temperature in the reactor is controlled by means of a hydrocarbon oil and especially with heavy gasoline or gas oil.

The aim of all measures according to the invention is finally to have a temperature below 300 ° C and neither feed still have hydrogen-containing reactor available. The removal of the hydrogen and the feed is done by purging of the reactor with an inert gas before, during and after cooling. The inert gas used is e.g. carbon dioxide and preferably Nitrogen used.

After the practically complete removal of the hydrocarbon

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until

and hydrogen residues from the reactor / to e.g. less than 1 volume percent sufficient purging with inert gas will add a small amount of air or oxygen to the purging gas. Initially In any case, only so much air or oxygen may be added to the purge gas that its oxygen content is less than 1 volume percent and the oxygen content of the purge gas must also be low enough to ensure that the temperature in the reactor does not exceed 300 ° C. Passing through the purge gas, which has a low oxygen content through the reactor is now continued. Oxygen consumption accompanied by a rise in temperature is observed, which, however, must be limited to a maximum of 300 ° C in all cases.

The oxygen content of the purging gas is preferably regulated in such a way that that the temperature of the purge gas withdrawn from the reactor remains below 150.degree. This temperature of the used Purge gas is a reliable indicator of the temperature in the reactor and can be easily determined.

According to one embodiment of the method according to the invention

the oxygen-containing purging gas is returned after being passed through the re-reactor. aktpr cooled, again mixed with oxygen and then to / It is readily apparent that this embodiment represents a saving compared to the sole use of fresh purge gas.

If the oxygen content in the purge gas is below 1 volume pro

cent the temperature rise in the reactor begins to decrease, the oxygen content of the purge gas gradually increases to above 1 percent by volume elevated. It must also be ensured continuously that the temperature in the reactor does not exceed values 300 ° C rises.

The purge gas is also preferred during this period in which the oxygen content of the purge gas is above 1 percent by volume returned and aer (the) consumed oxygen or Replaces air. In this period the temperature rise is due to the advanced controlled oxidation generally lower. The oxygen consumption is also lower.

In one embodiment of the invention, the oxygen content of the purge gas is increased at a predetermined rate, however, the increase is always postponed as long as the temperature in the reactor exceeds a predetermined value. Through this the passivation can be controlled in a relatively simple manner.

The oxygen content of the recycled purge gas is preferred replaced by adding a lower amount of air corresponding to a higher temperature rise in the reactor and vice versa. The oxidation is completely controlled and the temperature rise is limited to a relatively constant value, because in the event of an excessive rise in temperature, the cause for this rise, namely an excessively high oxygen content, is eliminated and if the temperature rise is too low, the insufficient

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corresponding oxygen supply is increased. An excessive rise in temperature has the disadvantage that components in the reactor that do not need to be oxidized are oxidized and one too low A rise in temperature means that the controlled oxidation is proceeding more slowly than absolutely necessary.

According to the invention, the oxygen partial pressure in the purge gas

at least 2
finally to / 0.2 kg / cm and in particular to at least 0.8

P this pressure
kg / cnr raised and / maintained for some time before opening the reactor. The reactor is preferably further flushed for some time, with practically no further evolution of heat being observed. Depending on the circumstances, this will take place in a sour

2 material partial pressure of at least 0.2 kg / cm or less takes place. The last two measures mentioned guarantee the best possible level of security.

Under certain conditions, there is a risk of the coal burning off locally, resulting in an uncontrolled increase in temperature in the zone with the spent coal and also to spread the undesirable temperature rise to others Put the catalyst can lead. This phenomenon occurs, for example, under conditions such as the presence of large quantities pyrophoric compounds in the reactor or in cases where the catalytic hydrogenation and / or when cooling the reactor not all points of the catalytic converter have been wetted by the coolant (such as heavy fuel or gas oil) and are therefore dry Zones exist. The latter phenomenon can in particular

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Occur in cases where the catalyst is significant is contaminated, which leads to poor distribution of the coolant over the catalyst.

Any risk of an uncontrolled increase in temperature in the reactor To avoid this, the reactor is preferably purged with a hydrocarbon oil along with the purge gas. Particularly suitable a petroleum-based hydrocarbon oil such as heavy gasoline or, preferably, gas oil. The feed rate of the Hydrocarbon oil to the reactor can fluctuate significantly. Preferably at least 5 percent of the during the catalytic Hydrogenation to the reactor fed feed initiated into the reactor. In particular, at least 10 percent of the aforementioned amount of hydrocarbon oil fed into the reactor. The circulation speed of the gas oil is during the Purge gas circulation approximately to the amount of the normal operation of the Reactor catalytically increased to be hydrogenated feed.

For complete wetting of the catalyst, it is advantageous to have the reactor containing the catalyst completely or practically completely fill with a hydrocarbon oil (especially with a gas oil) before using the oxygen-containing purge gas feeds into the reactor. The reactor is particularly advantageously filled from below with the hydrocarbon oil after virtually all of the hydrogen has been removed from the reactor. After the subsequent removal of the hydrocarbon oil The introduction of the flushing gas is started from the reactor. This purge gas can be used immediately or after some time

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a circulating hydrocarbon oil can be added.

It is desirable that the reactor be opened only at a relatively low temperature. The temperature when opening is preferably at most 6O ⁰ C. This temperature may have been already achieved by rinsing, but it is also possible to further cool the reactor after flushing. This ensures that the highest possible conversion of iron sulfide, for example, is carried out as long as possible at relatively high temperatures. In the latter case, pressure cooling, for example with air, is preferred since the reactor itself only cools down very slowly.

The process of the invention can be used, for example, in a reactor for the catalytic desulfurization of a liquid hydrocarbon feed be applied. Examples of such desulfurization processes are the desulfurization of light petroleum distillate fractions and the desulfurization of residual petroleum fractions.

However, the method according to the invention can also be used in other methods as with the catalytic reduction of sulfur compounds in a gaseous feed to hydrogen sulfide, be applied.

In the latter case, the feed can, for example, from the exhaust gas from a Claus plant for the production of elemental sulfur consist of gases containing sulfur compounds.

R η Q R A fi / Π 7 Δ 9

In the aforementioned desulfurization processes, the catalyst contains particularly expediently cobalt sulfide and / or nickel sulfide together with molybdenum sulfide and / or tungsten sulfide a carrier material, at least for the greater part of silicon dioxide and / or aluminum oxide. It has been found that such catalysts have pyrophoric properties. It however, all other types of catalysts which have pyrophoric properties can also be used by means of the catalyst according to the invention Procedure.

The invention provides an improvement to the process for continuous catalytic hydrogenation of one or more sulfur compounds in a liquid or gaseous feed with the formation of hydrogen sulfide, in which the feed to the hydrogenation through a reactor filled with catalyst is passed in the presence of added hydrogen at temperatures above 200 C. The improvement is that at the time a predetermined pressure drop throughout the reactor due to contamination of the catalyst layer in the feed end of the reactor of the reactor using one or more of the aforementioned embodiment (s) of the process according to the invention is put out of operation, after which the contaminated catalyst layer replaced and the reactor is put back into operation. One advantage of this method is that it does not, how so far, the entire amount of catalyst has to be replaced or regenerated. The method according to the invention has in particular for the catalytic desulfurization of petroleum residue fractions

reactors used have particular advantages, since very large amounts of catalyst are used in these cases. In practice

per reactor
are used at the time / total amounts of catalyst of about 750 m, in which the steam-air regeneration often leads to difficulties because about 0.5 to 1.0 tons of steam are required for regeneration per ton of catalyst per hour, which in many cases represents a very high peak load for the refinery. In this case, the method according to the invention has the advantage that the flushing gas can be recycled.

The pressure drop increases, especially with liquid feeds over a reactor for catalytic hydrogenation often because of the Deposition of slag on the first catalyst layer increases. This deposit often contains high levels of metals, such as metallic iron or metal salts that come from the system or from the feed. The deposition of slag means but not that the catalyst has been deactivated. When desulfurizing liquid feeds, the catalyst is used blocked in a reactor for the desulfurization of petroleum residue fractions, e.g. after about half a year, so far, that the upper catalyst layer must be replaced, while in the desulfurization of petroleum distillate fractions a blockage occurs only after a period of about 3 months to 2 years «In addition, too high a pressure drop occurs repeatedly before deactivation of the catalytic converter.

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An advantage of the passivation method according to the invention over the conventional regeneration of catalysts consists in the catalyst not subsequently sulphiding again must become. In the case of catalysts containing molybdenum, the conventional regeneration also has the disadvantage that it must be carried out at considerably higher temperatures under oxidative conditions, which leads to the risk of sublimation of molybdenum trioxide. It should also be noted that burning in conventional regeneration generally occurs at Temperatures of 370 to 470 C is carried out. The aforementioned embodiment of the method according to the invention also works based on the observation that the catalytic activity is not significantly increased by burning off the carbon, provided that the carbon is present in the usual percentages and that it is quite quickly when the reactor is restarted to a renewed deposition of carbon on the reactor occurs, without thereby increasing the activity of the catalyst Extent is affected. For this reason, it is not absolutely necessary to burn off the carbon during regeneration.

The aforesaid improvement in the continuous catalytic hydrogenation process is preferably carried out in such a manner carried out that the shutdown of the reactor Carbon dioxide content in the purge gas leaving the reactor is controlled during the time it takes to go to the reactor supplied purge gas oxygen is added and the oxygen

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The amount in the purging gas is reduced or completely oxygen-free Purge gas is used as long as the amount of carbon dioxide exceeds a predetermined value. As soon as the carbon dioxide level is in If the purge gas withdrawn from the reactor becomes too high, this excessively high carbon dioxide content in itself is an indication indicates that too much carbon has been burned off will. The carbon dioxide content is preferably kept at values below 0.04 percent by volume.

The examples illustrate the invention.

example 1

The drawing shows a diagrammatic representation of the oxygen content of the purge gas in the course of the passivation carried out according to the present example.

In a semi-industrial plant for the catalytic desulfurization of crude oil residue fractions, 1470 tons of crude oil residue fraction are produced desulfurized. The plant consists of a desulphurisation reactor filled with a catalyst. The catalyst contains 3.2 percent by weight cobalt and 9.2 percent by weight molybdenum

existing mainly of support material, a Aluminiumoxvd / _f which have been sulphided before. The reactor contains the catalyst as a fixed bed and the residue fraction to be treated is fed into the top of the reactor and withdrawn from the bottom of the reactor. Hydrogen flows through the reactor in parallel flow to the feed.

Immediately before the passivation according to the invention, the contains

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Catalyst 3.2 weight percent cobalt and 9.2 weight percent molybdenum. The catalyst at the top of the reactor contains 10.2 percent by weight Vanadium, 4.4 weight percent nickel, 0.7 weight percent Sodium and 0.40 weight percent iron. The catalyst at the bottom of the reactor contains 0.8 percent by weight vanadium, 0.3 percent by weight nickel, 0.2 percent by weight sodium and 0.04 percent by weight iron.

The reactor is now passivated, initially from the Residue fraction passes over to gas oil as a feed and thereby

feeds, continuously a hydrogen-rich gas mixture / the reactor is cooled in the course of 10 hours. During the cooling process, the temperature decrease is continuously less than 40 ° C per hour. The temperature of the gas fed to the reactor is 15 C, and after cooling it becomes a gas with a temperature also withdrawn from 15 C from the reactor. The gas oil feed is now interrupted and the reactor is flushed with a hydrogen-rich gas for about 6 hours. The hydrogen is then replaced by nitrogen and the reactor until a hydrogen concentration of less than 1 percent by volume is reached purged with nitrogen. The nitrogen pressure is then

increased to 6 kg / cm and the nitrogen recycled by means of a compressor.

Then air is injected into the nitrogen stream that is returned. The oxygen content of the purge gas fed into the reactor is measured continuously and is shown in the figure. In this figure, the time "t" is in hours on the

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7517869

The abscissa versus the oxygen content in percent by volume on the ordinate applied. The curve shows that oxygen is injected discontinuously into the purge gas. the However, the duration of the injection of oxygen increases continuously.

In the table are for the same time period as in the figure, the pressure used in the process (increased pressure), the duration of the individual air injection processes and the carbon dioxide content indicated in the purge gas leaving the reactor.

Tabel

Time,
Min. increased pressure,
kg / cm ² Duration of a
individual air
nozzles,
Min. Carbon dioxide
stop,
Volume percentage 30th 3.4 1 - 45 3.4 3 - 55 3.8 2 0.018 90 - 4.9 5 - 120 5.4 5 0.015 150 6.0 5 0.020 180 5.9 10 0.025 225 5.8 12th 0.020 285 5.5 15th 0.020 330 4.7 4O 0.020 450 0.8 full air circulation
tion 0.030 510 End of the passive voice
tion 0.040

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The figure shows that the passivation consumes oxygen will. The passivation process is also carried out continuously Determination of the carbon dioxide content of the purge gas leaving the reactor controlled. It has been found that between Large oxygen consumption occurs 2.5 and 4 hours after the start of the purging. It was also observed that

of the purge gas

because of the carbon dioxide content / when air is injected into the purge gas the carbon dioxide content of the air increases.

The temperature of the purge gas when it leaves the reactor is

O '

continuous 15 C. The passivation process according to the above Example is therefore carried out very carefully.

After flushing for 7.5 hours by means of the oxygen-containing nitrogen stream The passivation process is carried out after 30 minutes of compressed air circulation with an increasing increase in the oxygen content completed by the reactor and then opened the reactor. The catalyst does not show any pyrophoric properties at this point Properties more on.

A subsequent analysis of the catalyst shows that depending on the location in the reactor from which the catalyst was removed the catalyst contains about 7 to 15 weight percent carbon and about 7 to 8 weight percent sulfur.

Example 2 In the pilot plant described in Example 1 are

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106,000 tons of crude oil residue fraction desulphurized. The catalyst becomes quite heavily contaminated and contains a large amount of pyrophoric material.

The reactor is cooled to 40 ° C., hydrogen by nitrogen

2 is replaced, the nitrogen pressure is increased to 6 kg / cm, oxygen is added to the purge gas and the oxygen content of the purge gas is gradually increased, as described in Example 1.

The temperature in the reactor is measured at a few points and

of

the carbon dioxide emissions / exhaust gases determined from time to time. After about 20 hours (with an oxygen concentration in the purge gas of about 18 percent by volume) the carbon dioxide concentration in the exhaust gas increases drastically (from 0.03 to 0.3 percent by volume) and a sharp rise in temperature is measured in the end section of the reactor (from originally 40 up to 50 ° C to 100 ° C). The reactor is then opened and the catalyst is removed from the reactor. The catalyst from the end section of the reactor is hot and releases gas oil vapor and sulfur dioxide. Although the catalyst has no pyrophoric properties, there is a clear risk that a further increase in temperature will lead to uncontrolled burning of the carbon on the catalyst. This risk is avoided if the reactor is shut down according to Example 3.

Example 3

One for catalytic desulfurization roughly the same as in Example 2

Amount of the described / same crude oil residue fraction used cat-

lysator is cooled and the amount of hydrogen in the reactor means Nitrogen as flushing gas, as in Example 2, reduced to one percent by volume. The reactor is evacuated and gas oil from pumped down into the reactor until all of its catalyst contents are completely immersed in gas oil. Then the gas is oil withdrawn from the reactor and nitrogen at a pressure of

6 kg / cm fed into the reactor. Through the reactor nitrogen and at the same time an amount of gas oil of 10 percent of the During normal operation in the reactor, the amount of hydrocarbon to be desulphurized is passed. Then the Purge gas added one percent by volume of oxygen. After one hour, the nitrogen / oxygen flow is stopped and air is stopped

fed into the reactor at a pressure of 6 kg / cm. The Gasölurauf is gradually increased to the value of the amount of hydrocarbon to be desulfurized during normal operation of the reactor. After three hours of circulation of air and gas oil with no The reactor is opened. The catalyst has no pyrophores Properties on.

Claims

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Claims (20)

*
- 23 - Claims Process for shutting down a reactor filled with catalyst for the catalytic hydrogenation of a liquid or gaseous feed by passing the feed over the catalyst in the presence of added hydrogen, characterized in that (a) the temperature in the reactor, if this is more than 300 ⁰ C, lower is reduced to below 300 C and such / temperature is maintained until the reactor is opened; (b) the supply of the feed is interrupted and the hydrogen added during or after the reduction in temperature according to (a) is replaced by an inert gas; (c) the reactor is purged for some time with a purge gas consisting of the inert gas mentioned under (b); oxygen (d) then such an amount of / containing gas is added to the purge gas that the initial oxygen content of the purge gas is at most 1 percent by volume; (e) the oxygen content of the purge gas is increased and the purge gas feed is continued until there is practically no more heat generation in the reactor; (f) the oxygen partial pressure of the purge gas to at least 0.2 kg / cm is increased; (g) the reactor is opened. 5Q9846 / 0749 2. The method according to claim 1, characterized in that the temperature in the reactor by means of a hydrocarbon oil is reduced. 3. The method according to claim 2, characterized in that heavy fuel or gas oil is used as the hydrocarbon oil. 4. The method according to claim 1 to 3, characterized in that nitrogen is used as the inert gas. 5. The method according to claim 1 to 4, characterized in that the oxygen content in the flushing gas is regulated so that the temperature of the purge gas withdrawn from the reactor is kept below 150 ° C. 6. The method according to claim 1 to -5, characterized in that the oxygen-containing purge gas after passing through the Reakto, r. cooled, its depleted oxygen replaced and the purge gas is returned to the reactor. 7. The method according to claim 1 to 6, characterized in that that the oxygen partial pressure in the purge gas at the end of the open the reactor for some time at at least 0.8 kg / cm will. 8. The method according to claim 1 to 7, characterized in that that the reactor simultaneously with a hydrocarbon oil and 509846/07 49 is purged with the purge gas. 9. The method according to claim 8, characterized in that a gas oil is used as the hydrocarbon oil. 10. The method according to claim 8 and 9, characterized in that that the hydrocarbon oil to the reactor in a 5 to 25 weight percent of that in normal operation for the catalytic hydrogenation corresponding amount of feed supplied to the reactor is used. 11. The method according to claim 10, characterized in that the hydrocarbon oil in a 10 percent of the feed at Normal operation of the reactor amount is used. 12. The method according to claim 1 to 1-1, characterized in that the catalyst containing the reactor prior to the introduction of oxygen-containing purge gas in the. Reactor is completely or almost completely filled with a hydrocarbon oil. 13. The method according to claim 11, characterized in that a gas oil is used as the hydrocarbon oil. 14. The method according to claim 1 to 13, characterized in that Time during the
that while the purge gas fed into the reactor has an oxygen content, the carbon dioxide content of the purge gas withdrawn from the reactor is controlled and that the amount of oxygen added to the purge gas is reduced or brought to zero, 5Ω98Λ6 / 0 7Α9 so long / the carbon dioxide content of the withdrawn purge gas is a predetermined one Value exceeds. 15. The method according to claim 14, characterized in that the carbon dioxide content of the purge gas withdrawn from the reactor is kept below 0.04 percent by volume. 16 «. Method according to Claims 1 to 15, characterized in that that the temperature in the reactor before opening to a maximum of 60 ° C is held. 17. The method according to claim 1 to 16, characterized in that a reactor for the catalytic desulfurization of a liquid Hydrocarbon feed is put out of operation. 18. The method according to claim 1 to 16, characterized in that a reactor for the catalytic reduction of sulfur compounds is put out of operation in a gaseous feed to hydrogen sulfide. 19. The method according to claim 18, characterized in that a reactor for the catalytic reduction of the exhaust gas from a Claus plant for the production of elemental sulfur from gases containing sulfur compounds was shut down will. 20. The method according to claim 17, 18 or 19, characterized in that that a reactor is put out of operation with 509846/0 7 49 a cobalt sulfide and / or nickel sulfide and molybdenum sulfide and / or tungsten sulfide on at least a larger part Silicon dioxide and / or aluminum oxide existing carrier material containing catalyst is filled. 509846/07 49 Blank page