JPH07328455A - Regenerating method of catalyst - Google Patents

Abstract

PURPOSE:To efficiently remove carbon, polymerized material, iron oxide, or the like depositing on the surface of a catalyst and to regenerate the catalyst in a good state by cleaning a granular catalyst having decreased activity with liquid hydrocarbon while blowing a gaseous material at a specified average line velocity. CONSTITUTION:A granular catalyst having decreased activity is regenerated by cleaning with liquid hydrocarbon while blowing a gaseous material at 10-150 mm/min average line velocity. The gaseous material is blown through the lower part of a reactor. Further, the catalyst is cleaned with liquid hydrocarbon under conditions of 20-90 deg.C and 0-2.0kg/cm<2>G. Thus, carbon, polymerized material, iron oxide, and the like produced from hydrocarbon depositing on the surface of the catalyst can be efficiently removed, and the catalyst is preferably regenerated in a good state.

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 catalyst, and more particularly to a method for regenerating a catalyst for removing carbon, polymerized products and iron oxide deposited on the surface of the catalyst. .

[0002]

2. Description of the Related Art Generally, a catalyst for hydrogenating a hydrocarbon is poisoned by poisonous substances in the fluid as it is used, and rust introduced into the fluid, as well as a polymerization product and carbon content caused by the fluid itself. Deposition on the surface leads to a marked decrease in catalytic activity. In general, hydrogenated catalysts carry precious metals and are extremely expensive, so they cannot be frequently renewed each time they are deactivated, and it is desirable to establish a catalyst regeneration method to withstand commercial use. It was rare.

As a means for solving this problem, Japanese Patent Laid-Open No.
In “Catalyst Regeneration Method” of “50-153790”, a method of washing the catalyst with hydrocarbon is disclosed as a method of regenerating the solid particulate catalyst. This method treats the deteriorated catalyst at a temperature of 37.8-371.
The carbon content and hydrocarbon polymer substances deposited on the surface are removed by washing with liquid hydrocarbon at a temperature of 0.35 to 105.5 kg / cm ^{2 at} a temperature of ℃.

Although the catalyst activity was recovered to some extent by this method, the deposits could not be completely removed from the catalyst surface, and the catalyst active surface area was not completely recovered.
Even with such a technique, once the deposit adheres to the catalyst surface, the activity of the new catalyst cannot be reproduced,
There has been a need for an effective catalyst regeneration method by more complete removal of catalyst surface deposits.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for effectively regenerating a catalyst by more effectively removing deposits on the surface of the catalyst.

[0006]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors, the hydrocarbons deposited on the catalyst surface are caused by simultaneously ventilating a gaseous substance when the catalyst is washed with liquid hydrocarbons. It has been found that the carbon content and the hydrocarbon polymerization product can be effectively removed, and the present invention has been completed based on this finding.

That is, the present invention is a catalyst regeneration method in which a granular catalyst with reduced activity is washed with liquid hydrocarbon while blowing a gaseous substance at an average linear velocity of 10 to 150 mm / min. The type of catalyst used in the present invention is not particularly limited, but it is particularly effective for regeneration of the hydrogenation catalyst used in the following manufacturing fields. That is, by-product hydrogenation reaction of styrene in the purification of styrene monomer, hydrogenation reaction of benzene, hydrogenation reaction to synthesize cyclohexanol from phenol, hydrogenation reaction to produce isooctane from isooctene, acetylene in petroleum-based olefins Reactions such as hydrogenation and removal.

In the present invention, the term "activity is reduced" means that the active surface area of the catalyst is reduced by depositing carbon or hydrocarbon polymer substances on the catalyst surface, and the activity is lower than the original activity of the catalyst. Refers to the lowered state. The catalyst referred to in the present invention is a porous one in which a metal is supported on a carrier.
The carrier mentioned here is not particularly limited, but granular aluminum oxide, silica, silica-alumina, and activated carbon are preferable.

Examples of the catalyst metal mentioned here include nickel, cobalt, iron, copper, platinum, palladium, rhodium, ruthenium, iridium, rhenium and sulfides. The present invention is not particularly limited to these, but palladium is particularly preferable. The average particle size of the catalyst is not particularly limited in the present invention, but is generally 1 to 20 mm. The catalyst may have a cylindrical pellet shape, a spherical shape, or a tablet shape.

The amount of catalytic metal contained in the catalyst is controlled.
Although not limited, preferably 0.01 to 3% by weight, more preferably
Is 0.01 to 0.5% by weight. The form of the catalyst is shown in the table above.
The surface is impregnated with metal. The temperature during regeneration cleaning and
The pressure is preferably 20 ° C to 90 ° C, pressure 0kg / cm²G or
2 kg / cm²G, and more preferably at a temperature of 40 ° C to 80 ° C and pressure.
Force 0kg / cm²G to 1.5 kg / cm ²G, but especially limited to these
Not subject to proper cleaning and regeneration under other conditions
The effect is obtained.

The gaseous substance referred to in the present invention means the above temperature,
There is no particular limitation as long as it is a gas under pressure conditions, and examples thereof include nitrogen, oxygen, hydrogen, chlorine, ozone, carbon monoxide, oxygen dioxide, and a mixture of two or more thereof. Of these, nitrogen is preferable because it has low reactivity with the catalyst and liquid hydrocarbons. In the present invention,
By blowing in the gaseous substance, the liquid hydrocarbon at the interface in contact with the catalyst is easily renewed, and a strong cleaning effect is always maintained. As a result, deposits on the surface of the catalyst are effectively removed, allowing more complete regeneration of the catalyst.

In the present invention, if the flow rate of the gaseous substance blown during catalyst regeneration is too small, a sufficient cleaning effect cannot be obtained, and conversely, if the flow rate is too large, the catalyst layer is agitated and supported on the catalyst surface. The metal is removed to accelerate catalyst deterioration.
Therefore, the amount of gaseous substances blown in must be optimized. That is, the average linear velocity in the container of the gaseous substance blown into the catalyst layer during catalyst regeneration in the present invention is 10
It is ~ 150 (mm / min), preferably 30-50 (mm / min). By blowing the gaseous substance from the lower part of the reactor, that is, the lower part of the catalyst layer in this range, the metal is not peeled from the catalyst surface, and the deposits on the catalyst surface can be effectively removed.

[0013] Without being limited where the size of the reactor, in particular, catalyst loading is, reactor 0.5 m ³ to 20 m ³ is common. Since it is possible to effectively remove deposits on the catalyst surface by uniformly dispersing and supplying the gaseous substance, it is desirable to uniformly disperse and supply the gaseous substance with a sparger or the like.
The hole diameter of the sparger is not particularly limited to the present invention, but is a size that does not allow the catalyst to enter the sparger, and is generally 0.1 to 20 mm.

Further, the bubble diameter of the gaseous substance at the time of feeding is
Although closely related to the packed catalyst diameter and packing density, sparger hole diameter, under the above temperature, pressure and catalyst diameter conditions,
It is 0.01 to 20 mm. The liquid hydrocarbon used for washing is not particularly limited to the present invention, but an aromatic hydrocarbon derivative or an aliphatic hydrocarbon which is liquid under the above temperature and pressure conditions is preferable.

Examples of these include hydrocarbons such as benzene, ethylbenzene, styrene monomer, toluene, xylene, diethylbenzene, methanol, ethanol, and acetone methyl ethyl ketone, or a combination thereof. Usually, a catalyst is used from these. The liquid used in the process is selected. For example, when the catalyst used in the purification step of the crude styrene monomer is regenerated, it is preferable to use styrene monomer or ethylbenzene as the liquid hydrocarbon.

Further, the amount of liquid hydrocarbon to be supplied must be such that the catalyst is sufficiently immersed, and when regenerating by a batch operation, it is usually 1 to 5 times the catalyst volume, preferably 1 to 2 times.
Supply twice as much liquid hydrocarbons. According to a preferred embodiment of the present invention, when the need for catalyst regeneration arises due to increased catalyst surface deposits and reduced catalytically active surface area,
The process fluid remaining in the reactor is withdrawn while the catalyst remains charged in the reactor. Then, a liquid hydrocarbon as a cleaning liquid is introduced into this reactor until the catalyst in the reactor is sufficiently immersed. Then, the gaseous substance was blown into the bottom of the reactor, that is, the space below the catalyst layer,
This state is continued for a period of time to raise the bubbles of the gaseous substance.
After the lapse of time, the liquid hydrocarbons in the reactor are extracted, fresh liquid hydrocarbons are introduced again, and gaseous substances are also blown in. Generally, if the number of repetitions of this operation is large, the rate of removal of deposits on the surface of the catalyst is increased, but 1 to 5, preferably about 3 times is sufficient to obtain the desired effect.

The liquid hydrocarbon may be batch-processed as described above, but in some cases, may be supplied by continuous flow. The time required at this time is 1 to 4 as in batch processing.
It's about time.

[0018]

EXAMPLES The present invention will be specifically described with reference to the following examples.

[0019]

Example 1 In the styrene monomer production process quoted in this example, ethylbenzene was dehydrogenated by a dehydrogenation reactor to obtain a crude styrene monomer, which was then treated in a purification process. Before being sent to the process, it is passed through the catalytic reactor described in the present invention to remove phenylacetylene (hereinafter PA) which is an impurity in the crude styrene monomer. The composition of this crude styrene monomer is 65% by weight of styrene monomer, 34% by weight of ethylbenzene, 1% by weight of toluene, and PA by gas chromatography.
Was 32ppm in this. The catalyst used here is a granular aluminum oxide having an average particle diameter of 2 to 4 mm impregnated with 0.2 wt% of palladium.

The average residence time of crude styrene in the catalyst layer was 180 seconds. This retention time is used in all of the following examples and comparative examples. In the lower part of the reactor, a wire mesh is installed so that the catalyst does not pass through, and the catalyst is piled up on it. Crude styrene is introduced from the lower part of the reactor, passes through the catalyst layer, and then exits from the upper part of the reactor.

When it became necessary to regenerate the catalyst due to the decrease of the active surface area due to the deposition of carbon or hydrocarbon polymer substances on the surface of the catalyst, the following treatment was carried out. That is, the crude styrene remaining in the reactor is withdrawn from the bottom of the reactor.
When the liquid inside is sufficiently discharged, ethylbenzene is introduced to the extent that the catalyst in the reactor is immersed, and when the liquid is sufficiently filled, nitrogen gas is blown from the lower part of the reactor. Nitrogen gas is continuously blown through a gas sparger (pore diameter 1.5 mm, number of 16 holes) fixed on the wire net at the bottom of the reactor. At this time, the average linear velocity of nitrogen gas in the catalyst layer was 40 mm / min, and the required time was 2 hours. The temperature in the reactor was 60 ° C and the pressure was 1.0 kgG / cm ² .

After performing such regeneration treatment once, crude styrene was again passed through the reactor filled with this catalyst, and the PA conversion rates before and after the treatment were compared. In addition, the catalytic active surface area was also determined by the BET active surface area measuring method and is shown in Table 1.

[0023]

Example 2 In the styrene monomer production process quoted in this example, ethylbenzene is dehydrogenated by a dehydrogenation reactor to obtain a crude styrene monomer, which is then treated in the purification process. Before being sent to the reactor, it is passed through the catalytic reactor described in the present invention to remove PA which is an impurity in the crude styrene monomer. According to gas chromatography measurement, the composition of this crude styrene monomer was 40% by weight of styrene monomer, 58% by weight of ethylbenzene, 2% by weight of toluene, and PA was 40 ppm.
Further, the catalyst used here is a granular aluminum oxide having an average particle diameter of 3 to 5 mm impregnated with 0.3 wt% of palladium.

At the bottom of the reactor, there is installed a wire mesh that does not allow the catalyst to pass through, and the catalyst is piled up on it. Crude styrene is introduced from the lower part of the reactor, passes through the catalyst layer, and then exits from the upper part of the reactor. When it became necessary to regenerate the catalyst due to the reduction of the active surface area due to the deposition of carbon or hydrocarbon polymer on the surface of the catalyst, the following treatment was performed. That is, the crude styrene remaining in the reactor is withdrawn from the bottom of the reactor. When the liquid inside is sufficiently discharged, ethylbenzene is introduced to the extent that the catalyst in the reactor is immersed, and when the liquid is sufficiently filled, nitrogen gas is blown from the lower part of the reactor. Nitrogen gas is a gas sparger fixed on the wire mesh at the bottom of the reactor (pore diameter 1.5 mm, number of holes 1
6 pieces) are continuously blown in. At this time, the average linear velocity of nitrogen gas in the catalyst layer was 50 mm / min, and the required time was 2 hours. The temperature in the reactor is 50 ° C and the pressure is
It was 1.1 kgG / cm ² .

After carrying out such regeneration treatment once, crude styrene was again passed through the reactor filled with this catalyst, and the PA conversion rates before and after the treatment were compared. In addition, the catalytic active surface area was also determined by the BET active surface area measuring method and is shown in Table 1.

[0026]

Example 3 In the styrene monomer production process quoted in this example, ethylbenzene was dehydrogenated by a dehydrogenation reactor to obtain a crude styrene monomer, which was then treated in the purification process. Before being sent to the process, it is passed through the catalytic reactor described in the present invention to remove PA which is an impurity in the crude styrene monomer. According to gas chromatography measurement, the composition of this crude styrene monomer was 34% by weight of styrene monomer, 61% by weight of ethylbenzene, 5% by weight of toluene, and PA was 35 ppm. Further, the catalyst used here is a granular aluminum oxide having an average particle diameter of 1 to 3 mm impregnated with 0.4 wt% of palladium.

In the lower part of the reactor, a wire mesh having openings that do not allow the catalyst to pass is installed, and the catalyst is piled up on it. Crude styrene is introduced from the lower part of the reactor, passes through the catalyst layer, and then exits from the upper part of the reactor. When it became necessary to regenerate the catalyst due to the reduction of the active surface area due to the deposition of carbon or hydrocarbon polymer on the surface of the catalyst, the following treatment was performed. That is, the crude styrene remaining in the reactor is withdrawn from the bottom of the reactor. When the liquid inside is sufficiently discharged, ethylbenzene is introduced to the extent that the catalyst in the reactor is immersed, and when the liquid is sufficiently filled, nitrogen gas is blown from the lower part of the reactor. Nitrogen gas is a gas sparger fixed on the wire mesh at the bottom of the reactor (pore diameter 1.5 mm
16 pieces) are continuously blown through. At this time, the average linear velocity of nitrogen gas in the catalyst layer was 50 mm / min, and the required time was 4 hours. The temperature inside the reactor is 44 ° C and the pressure is
It was 0.5 kgG / cm ² .

After carrying out such a regeneration treatment once, crude styrene was again passed through the reactor filled with this catalyst, and the PA conversion rates before and after the treatment were compared. In addition, the catalytic active surface area was determined by the BET active surface area measuring method and is shown in Table 1.

[0029]

Example 4 In the styrene monomer production process quoted in this example, ethylbenzene was dehydrogenated by a dehydrogenation reactor to obtain a crude styrene monomer, which was then treated in a purification process. Before being sent to the process, it is passed through the catalytic reactor described in the present invention to remove PA which is an impurity in the crude styrene monomer. According to gas chromatography measurement, the composition of this crude styrene monomer was 56% by weight of styrene monomer, 42.5% by weight of ethylbenzene, 1.5% by weight of toluene, and PA was 25 ppm. The catalyst used here is granular aluminum oxide having an average particle size of 2 to 4 mm impregnated with 0.1 wt% of palladium.

In the lower part of the reactor, a wire mesh is installed so that the catalyst does not pass through, and the catalyst is piled up on it. Crude styrene is introduced from the lower part of the reactor and passed through the catalyst layer, and then from the upper part of the reactor. To go. When it became necessary to regenerate the catalyst due to the reduction of the active surface area due to the deposition of carbon or hydrocarbon polymer on the surface of the catalyst, the following treatment was performed. That is, the crude styrene remaining in the reactor is withdrawn from the bottom of the reactor. When the liquid inside is sufficiently discharged, ethylbenzene is introduced to the extent that the catalyst in the reactor is immersed, and when the liquid is sufficiently filled, nitrogen gas is blown from the lower part of the reactor. Nitrogen gas is continuously blown through a gas sparger (hole diameter: 1.5 mm, number of holes: 16) fixed on the wire mesh at the bottom of the reactor. At this time, the average linear velocity of nitrogen gas in the catalyst layer was 30 mm / min, and the required time was 1 hour. The temperature in the reactor was 80 ° C and the pressure was 1.5 kgG / cm ² .

After carrying out such regeneration treatment once, crude styrene was again passed through the reactor filled with this catalyst, and the PA conversion rates before and after the treatment were compared. In addition, a comparison of catalytic active surface areas is also shown in Table 1.

[0032]

Comparative Example 1 The same operation as in Example 1 was carried out except that in Example 1, no nitrogen was fed and the reactor filled with the catalyst was filled with ethylbenzene and allowed to stand for 2 hours.

[0033]

Comparative Example 2 The same operation as in Example 1 was carried out except that the average flow rate of nitrogen in Example 1 was 5 mm / min, the temperature in the reactor was 62 ° C., and the pressure was 0.9 kgG / cm ² .

[0034]

[Comparative Example 3] In Example 1, the average flow rate of nitrogen was 160 mm / min,
The temperature in the reactor was 57 ° C., the pressure was 1.2 kgG / cm ² , and the Pd content in the catalyst was 0.1 wt%.

[0035]

[Comparative Example 4] In Example 1, the average flow rate of nitrogen was 200 mm / min.
The temperature in the reactor was 67 ° C., the pressure was 1.1 kgG / cm ² , and the Pd content in the catalyst was 0.4 wt%. All operations were carried out under the same conditions as in Example 1.

[0036]

Reference Example 1 Using 2 m ³ of a new catalyst containing 0.2 wt% of Pd catalyst, the temperature in the reactor was 60 ° C., and the crude styrene having the composition described in Example 1 was used under the conditions of the pressure of 1.0 kgG / cm ^2. It was used to measure the PA concentration in crude styrene before and after the catalytic reactor. In addition, the catalytic active surface area before use was also measured.

[0037]

[Table 1]

[0038]

EFFECTS OF THE INVENTION By the catalyst regeneration method of the present invention, the deposits on the surface of the catalyst are removed more effectively, and the catalyst having a reduced catalytic active surface area and reduced activity is regenerated to a point close to the original catalytic activity. be able to.

Claims (3)

[Claims] 1. An average linear velocity of a gaseous substance of 10 to 150 m
A catalyst regeneration method in which a granular catalyst with reduced activity is washed with liquid hydrocarbon while being blown at m / min. 2. The method for regenerating a catalyst according to claim 1, wherein the gaseous substance is blown from the bottom of the reactor. 3. Temperature 20 to 90 ° C., pressure 0 to 2.0 kg / c
The catalyst regeneration method according to claim 1 or 2, wherein washing with a liquid hydrocarbon is performed under a condition of m ² G.