JPS62152545A - Removal of vanadium adhered to catalyst - Google Patents

Abstract

PURPOSE:To efficiently remove adhered vanadium, by contacting a catalyst to which vanadium was adhered by the catalytic cracking of a hydrocarbon stock material with a solid adsorbent at 650-850 deg.C in an atmosphere where vanadium is held to an oxide state. CONSTITUTION:A solid adsorbent is prepared by compounding two or more of compounds having compatibility with a vanadium compound held to an oxide state, for example, selected from aluminum oxide, magnesium oxide and calcium oxide. A catalyst to which vanadium was adhered by the catalytic cracking of a vanadium-containing hydrocarbon stock material is contacted with the aforementioned solid adsorbent at 650-850 deg.C in an atmosphere where vanadium is held to the oxide state to remove vanadium. A means of a fluidized bed for together fluidizing the catalyst and the solid adsorbent can be adapted to the contact of the catalyst with the solid adsorbent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing heavy metals, particularly vanadium, adhering to a catalyst from a catalyst by catalytically cracking a vanadium-containing hydrocarbon raw material.

Prior art) In the catalytic cracking of hydrogen combustion raw materials, especially hairy raw materials, heavy metals such as nickel, vanadium, and iron present in the raw materials gradually adhere to the catalyst, reducing catalyst activity and selectivity, and further It is known that it has an adverse effect on the life of the catalyst, and among heavy metals, vanadium is said to have a particularly large effect on the deterioration of the catalyst.

For this reason, in the fluid catalytic cracking method, an operating method is adopted in which a part of the balanced catalyst is extracted from the system and new catalyst is added to prevent the concentration of positive metal in the catalyst from exceeding a certain value.

In recent years, there has been a trend to use heavy oil containing a large amount of heavy metals as a raw material for catalytic cracking, and as a result, the rate of heavy metal deposition on the catalyst increases and the consumption of the catalyst increases.

A method of inactivating (passivating) the deposited metal has been proposed as a method to reduce catalyst deterioration due to deposited metal, but the passivating agent may scatter during catalyst regeneration, or depending on the type of deposited metal. There is no suitable passivation method, especially for vanadium.

As a method for removing /henadium on a single-strength catalyst.

■After the catalyst is oxidized in the air, it is treated with aqueous ammonia and NH
a Method for removing as V Oa (Edison R,
R.

et al; Hydrocarbon Proc
essing, 55. (5), 133 (197B)
), q) There is a method of reducing the catalyst and then chemically treating it with carbon tetrachloride to remove it as VCl* and VOCl3 (Japanese Patent Application Laid-Open No. 58-202049), but 1, the process is complicated, and If chemicals remain on the catalyst, there is a risk that they will be emitted as gas during the catalyst regeneration stage, which poses a problem.

Problems to be Solved by the Invention The present invention attempts to avoid a decrease in catalytic activity as much as possible and reduce the need to replenish new catalyst by removing vanadium, which forms a catalyst adhering to the catalyst, from the catalyst during catalytic cracking. It is something.

Means for Solving the Constituent Problems of the Invention The method for removing vanium attached to a catalyst according to the present invention is to catalytically crack a vanadium-containing hydrocarbon raw material to convert the vanadium-attached catalyst into an oxidized state. It consists of adsorbing the vanadium onto the solid absorbent by contacting it with the solid absorbent at a temperature of 650 DEG C. to 850 DEG C. in a maintained atmosphere r.

Note that vanadium here is a general term for vanadium elements as well as oxides and other compound forms.

To explain this in detail, 1. The present invention is applied to a catalyst to which vanadium is attached by catalytically cracking a vanadium-containing hydrocarbon raw material, and it is particularly applicable to a fluid catalytic cracking (FCC) catalyst. preferable.

The degree of adhesion of vanadium to the catalyst can be sufficiently treated even if it is as high as 8,000 PPM, but from the viewpoint of maintaining catalyst activity, adhesion should be as much as possible! , 1. It is preferable to implement the present invention while there are fewer than 1.

As the solid absorbent, one containing one or more of compounds 5 which have an affinity with the vanadium compound in the liquefied state, such as a/L/minilum oxide, magnesium oxide, and calcium oxide, is suitable. Examples of materials containing two or more types include calcined dolomite (CaO-MgO)
etc. is good. The shape of the solid absorbent is not particularly limited, but in the case of a fluidized bed or a moving bed, a granular one is suitable from the viewpoint of operability. In the case of a fixed layer, a shape that reduces the packing density is preferred.

A method for bringing the vanadium-attached catalyst into contact with the solid absorbent is to use a method in which at least one of the solid absorbent and the catalyst constantly moves, causing a collision between the solid absorbent and the catalyst. The L stage may be a fluidized bed in which both the catalyst and solid absorbent are fluidized, a moving bed in which the catalyst and solid absorbent are brought into contact with each other in a rotary kiln, stirred, and moved, or a fixed bed. Various methods can be applied.

If a fluidized bed is used, Ift dynamic catalytic cracking (FCC
) The regeneration tower of the apparatus may also be used for the absorption and removal treatment of henadium. In addition, a treatment device is installed separately from the regeneration tower, and a part of the catalyst with vanadium attached is continuously introduced from the regeneration tower into the treatment device, and the treatment device contacts the solid absorbent to absorb vanadium into the solid absorbent. The catalyst from which vanadium has been removed may be continuously returned to the regeneration tower.

The smaller the particle size of the solid absorbent, the larger the geometric surface area, which improves vanadium removal efficiency.

For example, in the treatment of FCC catalyst, the particle size of the solid absorbent is 20 to 200 particles when contact is carried out in a fluidized bed, and the particle size of solid absorbent is 150 particles when contact is carried out in a rotary kiln.
It is preferable to set it as L~5mm. When a solid absorbent is used as a fixed bed and the catalyst is passed through the fixed bed, the particle size of the solid absorbent is preferably larger than the particle size of the FCC catalyst.

Although it depends on the catalyst, a diameter of 1 mm or more is usually used.

Next, the absorption reaction is carried out under an atmosphere in which vanadium is maintained in an oxidized state.

For example, the contact between the catalyst and the solid absorbent is carried out at an elevated temperature in the presence of an oxygen-containing gas.

Alternatively, the catalyst may be previously treated at high temperature in the presence of an oxygen-containing gas to bring the vanadium into an oxidized state before being brought into contact with the solid sorbent, and then the solid sorbent may be heated to an oxidized state in a non-reducing atmosphere where the oxidation state is maintained. It may be brought into contact with.

In an atmosphere maintained at a high temperature and in an oxidizing state, once deposited vanadium moves easily between particles, so vanadium is effectively transferred to the solid absorbent. V20S
The melting point of vanadium is 670°C, and at temperatures higher than this, it becomes liquid and can be easily moved, and it is thought that it will move towards a solid absorbent that has a high affinity for vanadium. On the other hand, a reducing atmosphere is not suitable because it becomes v203 or v02 (melting point is about 1900° C.), making it difficult for vanadium to move.

The higher the reaction temperature is, the higher the vanadium removal rate will be, but if it is too high, it will accelerate the deterioration of the catalyst, so a temperature range of 650 to 850°C is appropriate. In the presence of water vapor, the temperature is preferably about 650 to 750°C.

The catalyst and solid absorbent can be separated after contact by selecting an appropriate method depending on the specific gravity and shape of the catalyst and solid absorbent, such as using a difference in specific gravity or using a cyclone or filter. good.

FCC catalyst with 8000 ppm of vanadium (specific gravity <2,6) and alumina with a particle size of 40 to 150 l (specific gravity >
3.0) at a ratio of 1:1 (weight ratio) into a processing container, air was blown in at 750° C. for 16 hours to fluidize and contact treatment was carried out. After treatment, the FCC catalyst and solid absorbent (alumina) were separated by specific gravity.

A metal analysis and an activity test (measurement of the yield of the fraction below 210° C. when desulfurized atmospheric residual oil is catalytically cracked) of the FCC catalyst after vanadium removal treatment were conducted.

The vanadium removal rate and activity test results were compared to the FCC catalyst without vanadium (standard example) and vanadium 80.
FCC with 00ppm attached and not subjected to vanadium removal treatment
The results are shown in Table 1 along with the activity test results of the catalyst (comparative example).

Example 2 The vanadium-attached FCC catalyst used in Example 1 (particle size 15
(0 or less) and alumina having a particle size of 300 to 600 tons were contacted in a rotary kiln in the presence of air. After processing F
The CC catalyst and alumina were separated using a sieve. Table 1 shows the vanadium removal rate and activity test results of the FCC catalyst.

Example 3 Vanadium-attached FCC catalyst used in Example 1 and particle size of 2 m
m of alumina was contact-treated in a rotary kiln in the presence of an oxygen-containing gas. After the treatment, the FCC catalyst and alumina were separated using a sieve. Table 1 shows the vanadium removal rate of the FCC catalyst.

Table 1 The activity (distillate yield below 210°C) of the FCC catalyst to which no vanadium is attached (standard example) is 36.6%, while that of the FCC catalyst to which 8000 ppm of vanadium is attached (comparative example) is 36.6%. Although the activity has decreased to 24.5%, it is recognized that the activity of the FCC catalyst devanadated according to the present invention has been recovered.

Furthermore, from Examples 2 and 3, it can be seen that the solid absorbent having a smaller particle size is more effective.

Examples 4 and 5 An FCC catalyst extracted from an actual device with 2710 ppm of vanadium attached (vanadium with a particle size of 63 L or more is in an oxidized state) was used as the raw material for Example 4, and an FCC catalyst with 5200 ppm of vanadium attached was used as the raw material for Example 4. (The particle size was 63 islands or larger and the vanadium was in an oxidized state after being oxidized in advance) was used as a raw material in Example 5.

Solid absorbent (alumina with a particle size of 63IL or less)
phosphorus) and 730 at a ratio of 1:1 (Iffi ratio).
℃, 6 hours, fluidize by blowing 100% steam,
Contact treated. After contact, the catalyst and solid absorbent are separated using a sieve.
Metal analysis and AST of FCC catalyst after vanadium removal treatment
Activity test by M method (Micr.

Activity Te5t) was performed. Result: 52
Shown in the table.

It can be seen that even when vanadium was removed at 730°C in the presence of steam, the activity was recovered by the vanadium removal treatment.

2nd Table Nirite cycle oil Example 6 FCC catalyst with 7000 ppm of vanadium attached and particle size 710-1680. of alumina in a rotary kiln in the presence of air. 1.3.12 at 750℃
．． 5. Table 3 shows the vanadium removal rates when contact treatment was carried out for 16 hours and 12.5 hours at 670°C.

As the contact time increases, the sodium removal rate decreases; however, in this case, almost equilibrium is reached in 12.5 hours, and even if the contact time is continued beyond that, the degree of improvement in the removal rate is small.

It is also understood that the higher the treatment temperature, the more effective it is.

11 mouths 1) Calcined dolomite (CaO/Mg0) with a particle size of 130-20og is used as a solid absorbent, and vanadium 7000p is used as the solid absorbent.
Contact treatment was carried out at 750° C. for 1 hour with the FCC catalyst to which pm was attached. After the treatment, the FCC catalyst and calcined dolomite were separated by centrifugation.

Yumu Seal J Calcined dolomite (CaO-MgO) with a particle size of 710-16804 is used as a solid absorbent, and vanadium 7000 is used as a solid absorbent.
A contact treatment was carried out at 750° C. for 1 hour with the FCC catalyst to which ppm was attached. After treatment, the FCC catalyst and calcined dolomite were separated using a sieve.

Example 9 Bugnesium oxide (M g O) with a particle size of 710 to 1680 g was used as a solid absorbent, and vanadium 7000 p
Contact treatment was carried out at 750° C. for 16 hours with the FCC catalyst to which pm was attached. After the treatment, the FCC catalyst and magnesium oxide were separated using a sieve.

Table 4 shows the /<Nadium removal rates in Examples 7 to 9.

From Examples 7 and 8, it can be seen that solid absorbents with smaller particle sizes are more effective.

Table 4 ■ FCC regeneration tower conditions (acid cumulative atmosphere 650-800°C)
The catalyst can be treated as is, and even if a small amount of solid absorbent is mixed into the catalyst, it will have an adverse effect on the reaction! The vanadium removal process is simplified.

■Since vanadium can be effectively removed, the life of the catalyst for catalytic cracking of hydrocarbon raw materials can be extended and the amount of new catalyst added can be reduced.

Claims (1)

[Claims] 1. A catalyst to which vanadium is attached by catalytic cracking of a hydrocarbon raw material containing vanadium is heated at 650°C to 850°C in an atmosphere where vanadium is maintained in an oxidized state.
A method for removing vanadium attached to a catalyst, which comprises bringing vanadium into contact with a solid absorbent at a temperature of . 2. The method according to claim 1, wherein the solid absorbent contains at least one selected from aluminum oxide, magnesium oxide, and calcium oxide. 3. The method according to claim 1, wherein the catalyst is a catalyst for fluid catalytic cracking. 4. The method according to claim 1, wherein the catalyst and the solid absorbent are brought into contact in the presence of an oxygen-containing gas. 5 Contact between the catalyst and the solid absorbent in the presence of water vapor
Claim 1 or 4 carried out at a temperature of ~750°C
The method described in section. 6. The method according to claim 1, wherein the contact between the catalyst and the solid absorbent is carried out in a fluidized bed. 7. The method according to claim 6, wherein the fluidized bed is a regeneration tower for a fluidized catalytic cracker. 8. The method according to claim 1, wherein the catalyst and the solid absorbent are brought into contact in a moving bed. 9. The method according to claim 8, wherein the moving bed is a rotary kiln.