JPH0796201A - Regeneration method of deactivated catalyst - Google Patents

Abstract

(57) [Summary] [Purpose] A catalyst that has been deactivated by coke or sulfur accumulation or platinum aggregation, or even an extremely deactivated catalyst can be easily regenerated, especially for regeneration of a catalyst deactivated by sulfur poisoning. It is to develop a method for regenerating a deactivated catalyst which is excellent and can recover the activity to the same degree as that of the new catalyst. [Structure] In regenerating a deactivated catalyst containing a zeolite carrying a Group VIII noble metal of the periodic table, the deactivated catalyst is subjected to decoking treatment under oxidizing conditions, and then subjected to hydrogen reduction treatment, followed by halogen treatment. Alternatively, it is a method for regenerating a deactivated catalyst, which comprises contact-treating with a liquid containing a halogen-containing compound and then calcining.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating a deactivated catalyst, and more specifically, effective regeneration of a deactivated catalyst containing a zeolite carrying a Group VIII noble metal of the Periodic Table, particularly a catalyst for producing an aromatic compound. Regarding the method.

[0002]

2. Description of the Related Art It has been conventionally known that various catalysts such as zeolite carrying a noble metal of Group VIII of the periodic table such as platinum are effective as catalysts for producing aromatic compounds. However, these catalysts are deactivated due to the accumulation of coke and sulfur on the noble metal and the growth of platinum particles and the like due to the reaction for a long time, and the function of the catalyst cannot be fulfilled satisfactorily. Become. It is well known that the coke deposits of the deactivated catalyst can be removed by heating the deactivated catalyst as described above (for example, platinum-supporting L-type zeolite etc.) in the presence of dilute oxygen at a temperature of 430 to 540 ° C. However, the decoking at high temperature causes the growth of the supported noble metal particles, that is, the reduction of the surface area of the noble metal particles, resulting in a decrease in the catalytic activity. Therefore, after the high temperature decoking, it is necessary to re-disperse the noble metal particles of the catalyst by contacting with air and a chlorine compound such as chlorine or carbon tetrachloride at a high temperature (oxychlorination treatment) (JP-A-60- 168540 and Japanese Patent Publication No. 24585/1990). However, in the above oxychlorination treatment, it is extremely difficult to regenerate a catalyst poisoned by sulfur or a catalyst which has been extremely deactivated.
Further, after decoking the deactivated catalyst under oxidizing conditions, it is washed with a neutral solution or an acidic solution and then treated with a basic aqueous solution,
A method of regenerating by washing with deionized water, drying and firing is disclosed (Japanese Patent Publication No. 62-500710). However, this method has a problem that the regeneration efficiency is poor, there are many treatment steps, the aqueous solution to be used needs to be 10 times or more the catalyst capacity, and there is no disclosure about sulfur removal. Further, a technique of regenerating the deactivated catalyst only by hydrogen reduction treatment (JP-A-57-24316), a technique of decoking in the presence of a halogen-containing compound (JP-A-1-231944), and platinum after decoking. After further agglomerating, the technology to remove sulfur (Table 1-5
(Japanese Patent Application Laid-Open No. Heisei 5-96177)
Etc. are disclosed.

[0003]

However, the catalyst regenerated by the method (1) has a low performance, and in the catalyst regeneration step, since the catalyst is decoked at a high temperature in the presence of a halogen-containing compound, the treatment equipment is Freon gas, which is expensive and has a problem of affecting the environment recently, is used as the halogen-containing compound, and its use is environmentally undesirable. Also, in the catalyst regeneration step, after removing coke by decoking, platinum is aggregated at a high temperature with a higher concentration of oxygen, and then contacted with a high concentration of hydrogen chloride to remove sulfur, and Since oxychlorination treatment is carried out to redisperse platinum, the treatment apparatus becomes expensive and there are many treatment steps. In the further catalyst regeneration step, the decoking catalyst is decoked, and the decoking catalyst is impregnated with an aqueous solution of a halogen-containing compound having a predetermined amount of supported halogen in water corresponding to the water content of the decoking catalyst. However, the sulfur is not sufficiently removed by this method, and it may be difficult to remove the sulfur depending on the deactivated catalyst. Therefore, the present inventors have solved the above-mentioned drawbacks of the prior art and can easily regenerate even a catalyst deactivated by coke or sulfur accumulation or platinum agglomeration, or an extremely deactivated catalyst, especially by sulfur poisoning. We have conducted intensive research to develop a method for regenerating a deactivated catalyst that is excellent in regenerating the deactivated catalyst and that can recover the activity to the same extent as the new catalyst.

[0004]

As a result, the deactivating catalyst is subjected to decoking treatment, hydrogen reduction treatment, and then treated with a liquid containing halogen or a halogen-containing compound to solve the above problems, It has been found that effective regeneration is achieved. The present invention has been completed based on such findings.

That is, according to the present invention, in regenerating a deactivated catalyst containing a zeolite carrying a Group VIII noble metal of the periodic table, the deactivated catalyst is subjected to a decoking treatment under oxidizing conditions and then a hydrogen reduction treatment. The present invention provides a method for regenerating a deactivated catalyst, which comprises performing a contact treatment with a liquid containing a halogen or a halogen-containing compound after the operation, and then calcining.

The catalyst to which the method of the present invention can be applied is a deactivated catalyst containing a zeolite carrying a Group VIII noble metal of the Periodic Table, particularly an aromatic production catalyst. here,
Zeolites may be either synthetic zeolites or natural zeolites, and X type, Y type, L type, mordenite type,
It may be of any type such as ZSM-5 type, but especially L
Molds are preferred. The metal supported is the first in the periodic table.
Group VIII noble metals such as Os, Ru, Rh, Ir, Pd,
It is Pt, and Pt is particularly preferable. Further, the catalyst may contain Re, Sn, Ge or the like as the second component of the metal to be supported. Zeolites are silica, alumina,
It may be molded with an inorganic binder such as aluminosilicate and viscosity.

The catalyst to which the present invention is applied is a zeolite or the like carrying a Group VIII noble metal of the periodic table as described above, such as those disclosed in JP-A-52-33632 and 57-2431.
6 gazette, the same 58-133835 gazette, the same 58-13.
No. 4035, No. 58-223614, No. 59.
-80333, 59-179589, 60-15489, 60-168539, 60-175548, 61-60787.
No. 61-125437 and No. 61-148.
No. 296, No. 61-151019, No. 62-
It is a very wide range of catalysts such as those disclosed in Japanese Patent No. 57653. Such a catalyst is particularly used for the production of aromatic compounds, for example, a reaction for producing benzene from light naphtha, a reaction for producing alkylbenzene from heavy naphtha, a catalyst for producing high octane gasoline from heavy naphtha, etc. Is effective as. When used for a long time in such a reaction, the catalyst is deactivated by accumulating coke, sulfur, etc. on the surface.

In the present invention, the thus deactivated catalyst is subjected to a decoking treatment under oxidizing conditions, then a hydrogen reduction treatment, and then a contact treatment with a liquid containing halogen or a halogen-containing compound, so-called liquid phase halogen. Then, it is regenerated by firing. The decoking treatment under oxidizing conditions can be performed by various methods. The processing conditions are, for example, when oxygen is used, the normal processing temperature is 1
0 to 600 ° C, preferably 100 to 550 ° C,
The treatment time is 1 to 48 hours, preferably 2 to 30 hours, and the treatment pressure is 0 to ²⁰ kg / cm ² G, preferably 0.
10 to 10 kg / cm ² G.

Next, in the method of the present invention, the catalyst deactivated as described above is subjected to decoking treatment and then hydrogen reduction treatment. Such hydrogen reduction treatment usually has a treatment temperature of 100.
To 600 ° C., preferably 200 to 550 ° C., the treatment time is 1 to 50 hours, preferably 1 to 30 hours,
Treatment pressure is 0 to ²⁰ kg / cm ² G, preferably 0 to 1
It is carried out under the condition of 0 kg / cm ² G.

Further, in the method of the present invention, as mentioned above, the deactivated catalyst is subjected to decoking treatment, hydrogen reduction treatment, and then contact treatment with liquid phase halogen (treatment with liquid phase halogen). This liquid-phase halogen treatment is carried out by, for example, water having a water content that matches the water content of the above-mentioned hydrogen-reduced catalyst, usually 0.2
It is carried out by bringing the catalyst into contact with a liquid (liquid-phase halogen) in which halogen or a halogen-containing compound is dissolved in ˜0.6 cc of water. Examples of this contact method include an atmospheric pressure impregnation method, a vacuum impregnation method, and an infiltration method. Examples of the halogen or the halogen-containing compound include bromine, hydrogen chloride, ammonium chloride, hydrogen fluoride, ammonium fluoride, hydrogen bromide, ammonium bromide, hydrogen iodide, ammonium iodide, and the like. , Hydrogen chloride, ammonium chloride and ammonium fluoride.
The halogen or halogen-containing compound used in this treatment may be one kind or a mixture of two or more kinds.

Liquid-phase halogen treatment thus obtained
The catalyst or its halogen or halogen-containing
The content of the compound is not particularly limited, but
Usually 0.1 to 10% by weight, preferably 0.3 to 5% by weight
It The firing is performed in the presence of oxygen, and the treatment temperature is usually 1
0 to 600 ° C, preferably 200 to 500 ° C,
Treatment time is 0.5 to 24 hours, preferably 1 to 10 hours
Yes, the processing pressure is 0 to 20 kg / cm²G, preferably
0-10kg / cm ²Is.

[0012]

EXAMPLES Next, the present invention will be described more specifically by way of Examples and Comparative Examples. Example 1 (a) Preparation of catalyst L-type zeolite (manufactured by Tosoh Corporation; TSZ-500KO)
A) 100 parts by weight of silica binder (Nissan Chemical Co., Ltd.)
(Manufactured by Snowtex) 20 parts by weight was added and kneaded and molded. Then, air baking was performed at 500 ° C. for 2 hours to obtain a silica binder-molded L-type zeolite. The obtained silica binder-molded L-type zeolite was filled in a quartz reaction tube and kept at 200 ° C. for 30 minutes while flowing nitrogen, after which the gas was switched from nitrogen to monochlorotrifluoromethane and heated to 500 ° C. After holding at 500 ° C. for 2 hours, the gas was switched from monochlorotrifluoromethane to nitrogen and the temperature was lowered to obtain a halogen-treated L-type zeolite.
Next, 0.4342 g of tetraammineplatinum chloride was dissolved in 10 g of deionized exchanged water to prepare an impregnation liquid. This impregnating solution was gradually added dropwise to 20 g of the above halogen-treated L-type zeolite with stirring to support platinum. Then, after drying overnight at room temperature, it was dried at 80 ° C. in air. The obtained catalyst is referred to as catalyst A.
Set to 1. The amount of sulfur in catalyst A1 was 20 ppm.

(B) Deactivation of catalyst The catalyst A1 prepared in (a) above was charged into a reaction tube and then treated in a hydrogen stream at 540 ° C. for 24 hours. Then, after adjusting the reaction pressure to 3 kg / cm ² G, hexane and hydrogen were respectively added to the weight hourly space velocity of 2 hr ⁻¹ ,
Hydrogen / hexane was supplied at 0.5 mol / 1 mol, and the catalyst was deactivated while adjusting the reaction temperature so that the aromatic yield at the outlet of the reaction tube was 60%. The resulting deactivated catalyst was used as catalyst A2.
And The sulfur amount of the catalyst A2 was 90 ppm.

(C) Regeneration of deactivated catalyst (1) Decoking treatment Catalyst A2 (4 g) was charged in a reaction tube and the pressure was 0 kg / cm.
² G, flowing nitrogen gas at a rate of 65 cc / min,
After heating up to 120 ° C. and holding at 120 ° C. for 3 hours, the pressure was raised to 4 kg / cm ² G, and the gas was mixed gas from nitrogen gas (gas composition (volume ratio); O ₂ / N ₂ = 0. 2/9
After switching to 9.8), the temperature was raised to 450 ° C. at a heating rate of 50 ° C./minute, and the temperature was maintained at 450 ° C. until the CO ₂ concentration at the outlet of the reaction tube became a predetermined concentration or less. The resulting decoking catalyst is designated as catalyst A3. The sulfur content of the decoking catalyst is 90p
pm and did not change from the amount of sulfur in the deactivated catalyst.

(2) Hydrogen reduction treatment The catalyst A3 (3 g) obtained in the above (1) was charged into a reaction tube, and hydrogen gas was flowed at a flow rate of 650 cc / min.
The temperature was raised to 0 ° C. and stored at 540 ° C. for 24 hours. The obtained reducing catalyst is referred to as catalyst A4. The amount of sulfur in catalyst A4 is 70
ppm and did not decrease to new catalyst level. (3) Halogen treatment and calcination The catalyst A4 (2 g) obtained in (2) above was impregnated with a solution obtained by mixing 0.06 g of ammonium chloride, 0.039 g of ammonium fluoride and 0.76 g of deionized exchanged water, After standing overnight at room temperature, water in the catalyst was removed at 100 ° C. with a rotary evaporator. The catalyst was regenerated by calcining the obtained catalyst at 400 ° C. for 3 hours in an air atmosphere. The obtained regenerated catalyst is referred to as catalyst A5. The sulfur content of catalyst A5 was 30 ppm, which was reduced to a level close to that of the new catalyst.

(D) Evaluation of catalyst The catalyst sieved from 16 to 32 mesh was placed in a quartz reaction tube, and quartz sand was placed above and below the catalyst. The catalyst was treated in a stream of hydrogen at 540 ° C. for 24 hours. Then, pressure 5k
After adjusting to g / cm ² G and temperature of 517 ° C., hexane and hydrogen were supplied at a weight hourly space velocity of 16 hr ⁻¹ and hydrogen / hexane = 5 mol / 1 mol, respectively, and data was taken at the time shown in Table 1. . The results obtained are shown in Table 1.

Example 2 A decoking catalyst was prepared in the same manner as in Example 1.
The obtained decoking catalyst (3 g) was charged into a reaction tube,
While flowing hydrogen gas at a flow rate of 650 cc / min, 300
The temperature was raised to 300C and the temperature was maintained at 300C for 5 hours. The sulfur content of the obtained reducing catalyst was 80 ppm, which was not reduced to the level of new catalyst. This reducing catalyst was subjected to halogen treatment and calcination in the same manner as in Example 1 to be regenerated. The obtained regenerated catalyst is referred to as catalyst A6. The amount of sulfur of catalyst A6 is 40p
It was pm. Next, this regenerated catalyst was subjected to reaction evaluation in the same manner as in Example 1. The results are shown in Table 1.

Example 3 A decoking catalyst was prepared in the same manner as in Example 1.
The resulting decoking catalyst was mixed with hydrogen gas while flowing 3
Hydrogen reduction was carried out in the same manner as in Example 2 except that the temperature was kept at 00 ° C for 24 hours. The sulfur content of the obtained reducing catalyst was 80 ppm, which was not reduced to the level of new catalyst. This reducing catalyst was subjected to halogen treatment and calcination in the same manner as in Example 1 to be regenerated. The obtained regenerated catalyst is referred to as catalyst A7. The amount of sulfur of catalyst A7 was 30 ppm. Next, this regenerated catalyst was subjected to reaction evaluation in the same manner as in Example 1. First result
Shown in the table.

Comparative Example 1 A decoking catalyst was prepared in the same manner as in Example 1.
The obtained decoking catalyst was regenerated by halogen treatment and calcination in the same manner as in Example 1 without hydrogen reduction. The regenerated catalyst thus obtained is referred to as catalyst B1. The sulfur amount of the catalyst B1 was 90 ppm, which did not change from the sulfur amount of the deactivated catalyst. Next, this regenerated catalyst was subjected to reaction evaluation in the same manner as in Example 1. The results are shown in Table 1.

[0020]

[Table 1]

[0021]

[Table 2]

As can be seen from Table 1, the amount of sulfur in the catalyst cannot be recovered to the level of the new catalyst only by decoking the liquid deactivated catalyst and the liquid phase halogen treatment. It can be seen that, by combining the phase halogen treatment, the sulfur content in the catalyst is reduced as much as that of the new catalyst, and the aromatic yield and the rate of aromatic yield reduction are also restored as much as the new catalyst. The rate of aromatic yield reduction in Table 1 was determined by the following equation. Aromatic yield decrease rate = [10 hr. Aromatic yield (wt%)
-20 hr. Aromatic yield (wt%)] / (20-10)

[0023]

According to the present invention, the deactivated catalyst is subjected to decoking treatment, hydrogen reduction treatment, and then liquid phase halogen treatment, whereby the activity of the regenerated catalyst can be easily restored to a level equal to or higher than that of the new catalyst. It is possible to reduce the sulfur content of the catalyst to the level of a new catalyst. Further, according to the present invention, the deactivated catalyst can be regenerated by using an inexpensive halogen or a halogen-containing compound.
Therefore, the regeneration method of the present invention is expected to be effectively used in the fields of petroleum refining, petrochemistry and the like.

Claims (1)

[Claims] 1. When regenerating a deactivated catalyst containing a zeolite carrying a Group VIII noble metal of the periodic table, the deactivated catalyst is subjected to decoking treatment under oxidizing conditions, and then subjected to hydrogen reduction treatment. A method for regenerating a deactivated catalyst, which comprises contact-treating with a liquid containing a halogen or a halogen-containing compound, and then calcining.