JPS59173136A - Regeneration process of catalyst - Google Patents

Abstract

PURPOSE:To regenerate easily a catalyst contg. oxides of iron, etc. on silica carrier and has been deactivated by being used in alkylation of phenols by gaseous phase contact with alcohols by treating the catalyst with gas contg. oxygen. CONSTITUTION:A catalyst contg. oxides of iron and/or V on a silica carrier, which has been deactivated by being used in alkylation of phenols by gaseous phase contact with alcohols, is allowed to contact with O2-contg. gas at 300- 800 deg.C. By this method, the deteriorated catalyst recovers high activity and high selectivity and becomes useful repeatedly and for a very long time. The strength and the activity of the catalyst are preserved even if the reaction and regeneration are repeated several times. The temp. where the deteriorated catalyst is allowed to contact with O2 for the first time is <=350 deg.C, more pref. <=300 deg.C; then the temp. is elevated at <=20 deg.C/min, more pref. at <=10 deg.C/min upto a predetermined temp.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for regenerating a catalyst used for algylation by bringing it into contact with phenol fAk alcohol in the gas phase. More specifically, phenol fEIt has a reduced activity when used in alkylation with alcohols at high temperatures and in the gas phase. , a method for easily and quickly regenerating the compound until it has sufficient activity and selectivity for use again.

In the alkylation reaction of phenols with alcohols, catalysts containing iron and vanadium oxides supported on lyka are highly active.

It has high selectivity and sufficient strength to withstand reaction conditions. However, this catalyst has the disadvantage that its activity decreases (hereinafter referred to as "deterioration") when the reaction continues for a long period of time. As the deterioration progresses, the conversion rate of 7 enols, ie, phenol and/or orthocresol, etc. decreases. In order to compensate for this, it is necessary to increase the reaction temperature, but as the reaction temperature increases, the amount of methanol (m) increases, so there is naturally a limit to how much the reaction temperature can be increased. Therefore, it is necessary to shut down the operation and perform a graceful catalyst replacement.
The T-Imagi was lost, and it was a big burden on the operation system. As a result of intensive studies aimed at improving this point, the inventors of the present invention have discovered a simple and highly effective method for regenerating a catalyst that increases the selectivity of the catalyst between two activities and allows the catalyst to be used for a long period of time. .

The catalyst regeneration method according to the present invention consists in contacting a catalyst containing iron and vanadium oxides supported on degraded silica with an oxygen-containing gas at a temperature of 300"C to 800C. The catalyst, which had deteriorated dramatically, regained high activity and high selectivity and could be used for an extremely long period of time. The strength and performance of the catalyst are also maintained.

Effective phenols used in the alkylation reaction to which this catalyst regeneration method is applied include phenol, 0-cresol, m-cresol, P-cresol, disilenols other than 2.6 xylenol, 〇-ethylphenol, 0-
Examples include globylphenol, 0-tertiary butylphenol, and methanol as the alcohol.

Examples of compounds obtained by the reaction include ethanol, n-glopanol, etc., and O-cresol, 2.6
-Ky/Lenol, 2.4-Ky7Lenol, 2.3.5-
Trimethylphenol.

Examples include 2.5.6-dolimethylphenol and 2.4.6-dolimethylphenol, and many of these compounds are important as raw material intermediates for synthetic resins, medicines, agricultural chemicals, polymer additives, and the like.

The catalyst to which this regeneration method is applied is 10 to 80% by weight of 7
Preferably, it is supported on liquid.

If the gluing force is less than 10%, the strength will decrease if the regeneration is repeated many times, and if it is more than 80%, the activity will be low, which is not preferable.

The supported metal oxides are mainly iron and/or hexa-nadium, and include chromium, indicum, bismuth, manganese, tin, and alkali') gold.

It is used for materials containing oxides of alkaline earth metals, rare earth metals, etc.

The present invention can be applied to catalysts for both fixed bed and fluidized bed reaction methods, but catalysts used in particular for fluidized beds have a spherical shape with a diameter of 10 to 200 μm. This is preferable, and since the catalysts collide violently with each other and the vessel wall and the catalyst, it is essential that the catalyst be strong enough to withstand such collisions.

The inventor investigated the deteriorated catalyst using methods such as X-ray diffraction, and found that the metal oxide in the deteriorated catalyst was reduced to a lower oxidation state than the oxidation state of the metal in the undegraded catalyst before the reaction. I found out that On the other hand, it was found that a large amount of carbon was deposited on the deteriorated catalyst, amounting to 1 to several tens of grams per 100 # of catalysts. Based on these findings, we investigated and succeeded in regenerating the catalyst by treating the deteriorated catalyst with oxygen-containing gas to return it to a highly oxidized state and removing the precipitated carbon as 1cO2. be.

Catalyst regeneration may be carried out in the core vessel or may be removed from the reactor, carried out in a separate device, and returned to the reactor. Regeneration conditions vary depending on the type of catalyst, but the treatment temperature is 600°C to 80°C.
A range of 0°C is preferred. If the temperature is less than 300°C, the regeneration does not proceed sufficiently, which is undesirable, as it takes an extremely long time to regenerate, and if the temperature is over 800°C, the crystallization of the support, which is the glue, progresses and the strength of the catalyst decreases, which is undesirable. It is.

Furthermore, the present inventors have discovered that when regenerating a deteriorated catalyst, if the catalyst and oxygen are suddenly brought into contact at a high temperature, the strength of the catalyst decreases.

That is, the temperature at which the deteriorated catalyst and oxygen are brought into contact for the first time is less than 650°C, more preferably less than 600°C, and then the temperature is increased at a rate of 20°C/min or less, more preferably 10°C/min. Preferably, the temperature is raised to a predetermined processing temperature at a heating rate of no more than per minute.

If oxygen supply is started at a temperature higher than 650° C. or if the regeneration treatment temperature is increased at a temperature increase rate of 20° C./min or more, the strength of the catalyst is reduced and the activity and selectivity of the catalyst are also reduced.

According to the inventors' careful and in-depth study on regeneration, when the degraded IJ catalyst is brought into contact with r2 elements, the catalyst that has been reduced to a low oxidation state is first returned to a high oxidation state, and then the catalyst that has adhered to the catalyst is returned to a high oxidation state. Catalyst regeneration is most complete when a method of oxidizing carbonaceous material is employed. When the temperature is relatively low, the oxidation of the melting medium takes precedence over the oxidation of the carbonaceous material, so it is preferable to start the contact between the catalyst and oxygen at a relatively low temperature in order to regenerate the catalyst.

As the oxygen-containing gas, it is convenient to use air. Furthermore, water vapor or an inert gas may be present in order to control the reaction temperature and the like, if necessary. It is desirable to carry out regeneration until very little carbon dioxide gas is generated.

When regenerating the catalyst, it is desirable to stop the supply of reaction raw materials and to sufficiently purge the interior of the reactor with water or an inert gas such as nitrogen, in order to ensure safety such as preventing explosions. The linear velocity of the oxygen-containing gas during regeneration is 0.5 to iQ[
] cuL/sec is preferred. It is also possible to continuously withdraw the catalyst from the reactor, continuously regenerate it in another regenerator, and return it to the reactor again.

The present invention will be explained in more detail with reference to Examples below. Phenol conversion rate 2 selectivity in Examples.

Methanol selectivity is defined by the following equation.

× 100 □1 Double iron (Fg(N03n3)
・9H20) 2020Il and 30ffi 5i
Noriyoku sol (Yasan Kagaku Snowtex N) containing 02
) The raw material slurry obtained by adding 2,850 g'(f) was sent to a co-current jet 8 dryer and dried.The obtained dry powder was heated at 650°C using a tunnel kiln.
After preliminary firing for 2 hours at 750°C, firing was performed for 3 hours. This catalyst had a particle size of 20 to 200 microns and was found to have a spherical shape suitable for a fluidized bed when observed using a Similon microscope.

This catalyst 300. Pt was charged into a fluidized bed reactor having a diameter of 6 inches, and the pressure was maintained at atmospheric pressure, and a raw material liquid having a molar ratio of phenol, methanol, and water of 1:3 was introduced into the reactor through an evaporator. At this time, the flow rate was fully adjusted so that the contact time between the raw material gas and the catalyst was 6 seconds. The reaction temperature was initially set at 320° C., and thereafter was gradually increased as the catalyst deteriorated so that the conversion rate of phenol remained approximately constant.

When the reaction time reached 600 to 700 hours, the reaction temperature decreased to the initial level.The CH30H selectivity decreased by about 15% compared to the initial stage of the reaction, so the supply of the reaction raw materials was stopped, and the inside of the reactor was sufficiently replaced with steam to complete the reaction. After the temperature of the vessel was lowered to 250°C, air was introduced. Air was supplied at a gas linear velocity of 5 cIL/sec, and the treatment temperature was raised from 250°C to 450°C over 2 hours, that is, at an average heating rate of 1.7°C/min, and held at 450°C for 2 hours. reproduction? Completed. Thereafter, the reactor temperature was lowered to 320°C, and the reaction raw materials were supplied to restart the reaction. The reaction conditions were adjusted to the initial conditions of the first reaction.

The reaction results were determined by passing the gas flowing out of the reactor through a panoramic condenser and performing R1'J analysis using gas chromatography. The results are shown in Cloth-1.

First, an abrasion resistance test was conducted on the catalyst before and after the reaction. Abrasion testing is typically performed as a test method for FCC catalysts, in which approximately 50.9 i. A treetop scale was introduced, and air was flowed through the perforated disk at a rate of 15 cubic feet per hour to create a vigorous flow. It was calculated as the ratio of the weight of the catalyst to the initial injection sound. The results are shown in Cloth-1.

[Example 2] In the same manner as in Example 1, the atomic ratio of V*FepK was (1:1
:0.025) as i'! Using the same apparatus as in Example 1, reaction and regeneration were performed under the same conditions as in Example 1.

As can be seen from Table 1, when this regeneration method is used, the catalyst activity and methanol selectivity completely return to their initial values, and the wear resistance of the catalyst does not decrease.

Table 1 [Example 3] Using the same equipment as in Example 1.2, the same reaction was carried out, and the deteriorated catalyst was taken out from the reactor, pumped out, and put into an air atmosphere positive electric heating fixed furnace. Power supply case 1 (Raise the temperature to 250℃ at a temperature increase rate of J℃/min, then 250℃ for 60 minutes.
After that, the temperature was raised to 450°C at a heating rate of 5°C/min, and after being left at 450°C for 2 hours, the catalyst was taken out and returned to the reactor, and the same reaction was restarted.

Table 2 shows the regeneration treatment conditions and reaction results.

[Comparative Examples 1 and 2] Under the same conditions as in Example 9113, only the maximum regeneration treatment temperature was 2.
Table 2 shows the results obtained at 00°C and 1000°C.

Table 2 [Example 4] Add 1 ton of pure water to 1 ton of nitric acid ['Cr(NOQx ・9H2
0.18g and ferric nitrate (Fg(NO3): l・9
The raw material slurry obtained by adding H20]404ti was evaporated to dryness on a hot water bath, and then heated at 350°C for 2 hours.
Pre-fire for an hour. This is i20. After crushing P and Shi,
60 weight 'Mk'io 5j02': Add 1'OF' of silica sol (Snowtex N, manufactured by Kaguchi Kagaku Co., Ltd.) containing 1'OF', mix well while heating on a hot water bath, and adjust to an appropriate moisture concentration that allows molding. After that, it was molded into a cylindrical shape with a diameter of 5 ko and a length of 5 ml. This was dried at 100°C for 12 hours and then fired at 600°C for 3 hours.

A glass reaction tube with an inner diameter of 2 cm was filled with 6 cc of this catalyst, the reaction temperature was kept at 640°C, and the pressure was kept at atmospheric pressure, and a raw material liquid with a molar ratio of phenol and methanol of 1:6 was added to the evaporator. introduced through.

At this time, the flow rate was adjusted such that the contact time between the raw material gas and the catalyst was 3.5 seconds, and the reaction was continued for 600 hours. The phenol conversion rate 50 hours after the start of the reaction was 98%, and the methanol escape rate was 72%. Deterioration of catalyst activity/
The reaction temperature was gradually increased by ξ to keep the phenol conversion rate constant.

The temperature for 300 hours was 665°C, and the methanol selectivity decreased to 45%, so the supply of raw materials was stopped.

The inside of the reactor was optically replaced with protein 2, and the temperature of the reactor was changed to 40°C.
The air temperature was lowered to ℃ and the air conditioner was fully started.

Air was supplied at a flow rate such that the linear gas velocity was 10 crn/sec, and the treatment temperature was increased from 2-40°C to 300°C over 1 hour, i.e. at an average rate of 1°C/min, and then from 300°C to 5°C.
The geothermal temperature was raised to 00°C over 60 minutes, ie, at an average rate of 6.7°C/min, and maintained at 500°C for 1 hour to complete regeneration.

After this, the reaction enrichment was returned to 340°C and the reaction source n
The reaction yarn production that restarted the reaction by supplying it was adjusted to the conditions of the first reaction.

Fifty hours after restarting the reaction, the phenol conversion rate was 98.1%, and the methanol selectivity was 73%, indicating that the oxidation process had been completely regenerated.

The reaction was further continued, and at 60'0 hours after restarting the reaction, the reaction was stopped and regenerated under the same conditions. React like this,
Regeneration was repeated for a total of 5 cycles.

The phenol conversion rate at 50 hours of the 5th cycle was 98.
2%, the methanol selectivity was 72.5%, and it was found that the catalyst remained unchanged even after 5 cycles of reaction regeneration. 5 again? After the cycle was completed, the catalyst was removed from the reactor and inspected, but no cracking or powdering had occurred.

[Example 5] A catalyst degraded by reaction waves in the same manner as the experimental crab was placed in a fixed furnace heated to 150°C, held at this temperature for 60 minutes, and then raised to 600°C at a rate of 10°C/min. It was warmed up and left at this temperature for 2 hours. Thereafter, the reaction was started in the same manner as in Example 3.

[Comparative Examples 3 and 4] Temperature rising rate was 0°C/min, initial fixed furnace temperature'
fr: After regeneration was performed in the same manner as in Example 5 except that the temperature was 400°C, the reaction was restarted.

Table 3 does not show the regeneration treatment conditions and reaction results of Example 5 and Comparative Examples 3 and 4, and the results of the wear test before and after the reaction. It can be seen from this that even if the temperature increase rate is too fast or the regeneration start temperature is too high, the activity will not return sufficiently and the strength of the catalyst will deteriorate.

Table-3

Claims (3)

[Claims] (1) Used for alkylation in the gas phase by contacting phenol ak alcohol with a catalyst containing a total of oxides of iron or vanadium supported on lyka with low activity T in an oxygen-containing gas. 1. A method for regenerating a catalyst, the method comprising: (2) The method for repopulating a catalyst according to item 1 of the preceding claim, wherein the maximum treatment temperature is 800°C or less. (3) The catalyst according to claim 1, wherein the temperature at the start of the entire regeneration process with the acid-containing M gas is less than 650°C, and the temperature increase rate is 0°C/min or less throughout the treatment temperature. Raw method.