JPH0775671B2 - Highly functionalized zeolite catalyst - Google Patents

Description

TECHNICAL FIELD The present invention relates to a highly functionalized method for a zeolite catalyst.

(Problems to be Solved by Conventional Techniques and Inventions) Zeolite crystal particles have a fine pore structure and strong acidity, so that they can react with only specific molecules that can penetrate into the pores. It is used in various fields as a high-quality catalyst, adsorbent, and separating agent. Among them, it is well known to use zeolite as a catalyst for petroleum reforming.

However, since the pore size of zeolite is very small, with a pore size of 10 Å or less, heavy aromatic compounds and basic compounds that are catalyst poisons for ordinary catalysts enter inside the pores. I can't. Therefore, the active sites in the pores of zeolite are very unlikely to be poisoned by these substances. However, since the outer surface of the zeolite particles is also active, the pores are blocked by these poisoning substances adsorbed thereto, and as a result, the performance as a catalyst or the like is often deteriorated.

Conventionally, when zeolite is used as a catalyst, an adsorbent, a separating agent, etc., there are cases in which zeolite microcrystals are directly used, but in most cases, they are molded and used. For example, industrial fixed bed catalysts are generally used after being molded into pellets having a diameter of several millimeters in order to prevent clogging of the reaction tower.

Zeolite particles have a fine pore structure, but in order to effectively utilize the inside of the pores in the molded state, it is necessary to connect the zeolite particles with macropores of an appropriate size.
Since the size of macropores varies depending on the purpose of use and the conditions of use of zeolite, it is desirable to be able to control the size.

Zeolite particles have a weak adhesive force and are hard to be shaped in strength, and therefore, various types of substances such as alumina are generally added to maintain the strength during the shaping. However, these additive substances often deteriorate the performance as a catalyst inside the pores of zeolite particles, for example.

On the other hand, since zeolite has a very strong adsorptive power, its activity is hindered by the adsorption of heavy unsaturated fractions, especially when it is used as a catalyst. Therefore, it is desirable that the additive used for forming the zeolite is a substance that is not easily poisoned by heavy fractions and has a hydrogenation ability.

An object of the present invention is to reinforce the above-mentioned weak points of zeolite and provide a highly functionalized method as a zeolite catalyst for petroleum reforming.

Here, making a zeolite catalyst highly functional means controlling the diameter and volume of the macropores that connect the pores of the zeolite to enhance the activity of the zeolite catalyst, increase its strength, and prevent it from being poisoned by heavy fractions. Means to do.

That is, the present invention provides a method for forming a zeolite-containing particle having high activity and high strength capable of effectively utilizing the zeolite present inside the particle, and preventing deterioration of the zeolite due to a heavy unsaturated compound, and a catalyst thereof. The purpose is to do.

(Means for Solving the Problem) As a result of intensive studies for many years to solve the above problems, the present inventors have found that (1) zinc oxide-chromium oxide composite oxide is a heavy aromatic or base. It is less susceptible to inhibition by organic substances and has a stronger hydrogenation ability, so it has a large function of protecting the outer surface of the zeolite particles and maintaining the activity inside the pores. (2) Zinc oxide-chromium oxide composite oxidation The product can control the size of medium pores of 100 Å or less and fairly large pores of 100 Å or more by a preparation method within a considerable range, and (3) zinc oxide-chromium oxide composite oxide. It was found that, even when molded in the coexistence of zeolite with a certain size of macropores (the above-mentioned pores larger than 10Å), high strength can be obtained. The present invention has been completed based on these findings.

That is, the present invention provides (1) a zeolite for petroleum reforming, characterized in that the zeolite is molded together with 1 to 500 times its weight of zinc oxide-chromium oxide composite oxide (Zn / Cr atomic ratio = 0.1 to 10). (2) Zinc oxide-chromium oxide composite oxide (Zn / Cr atomic ratio = 0.1 to 10) in 1 to 500 times by weight of zeolite and 1 to 500 times by weight of VIb group of zeolite. A method for enhancing the functionality of a zeolite catalyst for petroleum reforming, which comprises molding with a metal or a Group VIII metal, a compound thereof, or a mixture thereof, and (3) a molding is performed under pressure ( 1)
The method according to item (2) is provided.

In the method of the present invention, the zinc oxide has a Zn / Cr ratio (atomic ratio) of 0.1 to 10, preferably 1 to 4 in the zeolite particles.
A zeolite catalyst for petroleum reforming is highly functionalized by adding a complex oxide of chromium oxide to 1 to 500 times by weight, preferably 10 to 50 times by weight of zeolite and molding together.

In the method of the present invention, the catalyst can be made highly functional by setting the above mixing ratio of the zinc oxide-chromium oxide composite oxide and the zeolite. If it is less than 1, the strength is insufficient, and if it is more than 500, the strength is high but the activity as a zeolite is low, which is not preferable. If the atomic ratio of Zn and Cr in the composite oxide is less than 0.1 or more than 10, the strength will be insufficient and molding will be difficult.

In the method of the present invention, zeolite and zinc oxide-chromium oxide composite oxide, if necessary, nickel, iron, group VIII metals such as cobalt, molybdenum, VIb group metals such as tungsten, silka, alumina, vanadium, Metals such as phosphorus, calcium and magnesium, metal oxides or metal sulfides of these metals, are used in an amount of 100% by weight or less, preferably 5% by weight or less of the zinc oxide-chromium oxide composite oxide.
Add ~ 20 weight percent to further improve catalyst performance.

Next, the reason why the macropores of zeolite can be controlled by the method of the present invention will be explained. This is because the zinc oxide-chromium oxide composite oxide transits through various crystal structures in the preparation stage to release water of crystallization, and these are used to control the pores. According to the present invention, the zeolite particles have a fine pore structure, but in order to effectively utilize the inside of the pores in the molded state, the zeolite is molded together with the zinc oxide-chromium oxide composite oxide. This allows the necessary macropores to be adjusted over a fairly wide range.

The zeolite catalyst highly functionalized by the method of the present invention can control the macropores by further calcination or reduction.

(Effect of the Invention) According to the method of the present invention, a very highly active zeolite catalyst for petroleum reforming can be prepared while controlling macropores. This zeolite catalyst can decompose linear paraffins at a lower reaction temperature than conventional catalysts, for example, as a catalyst in the decomposition of linear paraffins in vacuum gas oil. Further, this zeolite catalyst has a large physical strength despite having macropores larger than those of conventional zeolites, and is not easily poisoned by heavy fractions.

Further, since the highly functionalized zeolite catalyst of the present invention has high activity, the amount of catalyst used can be naturally reduced, or the reaction tower, adsorption tower, etc. can be downsized. Furthermore, since even the zeolite inside the particles can be effectively used, it is possible to use as a petroleum refining catalyst, etc. even a heavier fraction than before.

(Example) Next, the present invention will be described in more detail based on examples.

Example 1 Zinc oxide-chromium oxide composite oxide (Zn / Cr atomic ratio =
2) Paste containing 15% by weight of zeolite was molded into tablets with a diameter of 10 mm at three different pressures, which were crushed and sorted into 0.59 to 0.84 mm at 500 ° C in air. FIG. 1 shows the pore distribution of the product that was calcined, cooled, and then heated again to 500 ° C. and reduced in a hydrogen stream (provided with hydrogenation activity).

Sample 1 in the first figure, not containing added little molding pressure, Sample 2, which was molded at a pressure of 3.2t / cm ^3, Sample 3, a material obtained by molding at a pressure of 4.8t / cm ³ Represent.

The sample has medium pores with a radius of 80Å and relatively large pores of 100 to 300Å, and it is shown that the volume of the former pores and the diameter of the latter pores can be controlled by the molding pressure. Has been done.

Example 2 Since various crystal forms exist in the zinc oxide-chromium oxide composite oxide, the macropores can be controlled not only by the molding pressure but also by the treatment method after molding.

Zinc oxide-chromium oxide composite oxide (Zn / Cr atomic ratio =
The paste containing 15% by weight of zeolite with respect to 2) was molded at a pressure close to normal pressure, and the paste was crushed to a pressure of 0.
FIG. 2 shows the pore distribution of the particles sorted into 59 to 0.84 mm and treated by the four methods.

Sample 1 in FIG. 2 was calcined in air at 500 ° C., cooled and then reduced in a hydrogen stream while raising the temperature to 500 ° C. Sample 2 was calcined in air at 500 ° C. and cooled again. 500 ° C
A sample reduced by heating in a mixed gas flow of hydrogen / carbon monoxide / steam while being heated up to 50 ° C., a sample 3 fired at 500 ° C. in air, and a sample 4 fired at 250 ° C. in air. (The reduced product was given hydrogenation activity.) FIG. 2 shows that the pore volume and pore diameter can be controlled by the treatment conditions after molding.

Example 3 Zeolites have fine pores and strong acid properties, so
It is important as a catalyst that selectively decomposes compounds with a specific structure that can enter the pores, but when used by molding, it has a large diffusion resistance in the pores and can effectively utilize the original activity of zeolite. Have difficulty.

FIG. 3 shows the result of decomposing linear paraffins in vacuum gas oil using a zeolite catalyst prepared by controlling the macropores as described below by the method of the present invention. For reference, FIG. 3 also shows the results obtained with a nickel-molybdenum-alumina catalyst which is a typical petroleum refining catalyst.

The reaction uses a high-pressure flow reactor, the amount of catalyst used is 50 ml, LH
At SV 1hr ^-1 , the oiling time is almost 2 weeks. Zeolite catalyst is a composite oxide of zinc oxide-chromium oxide (Zn / Cr
A paste containing 15% by weight of zeolite with respect to the atomic ratio = 2) was molded at a pressure close to normal pressure, crushed and sorted into 0.59 to 0.84 mm, and the same as sample 1 of example 2 It is a product that has been treated (hydrogenation activity has been imparted by reduction).

The highly functionalized zeolite catalyst according to the present invention has a very high activity, and at the reaction temperature of 325 ° C., almost 100% of the linear paraffins in the vacuum gas oil were decomposed.

Selective decomposition of linear paraffins in vacuum gas oil has been industrialized in several processes as catalytic dewaxing method.
Its detailed operating conditions have not been reported, but generally 350
A reaction temperature of around 0 ° C. has been employed and it is clear that the treatment according to the invention dramatically improves the function of the zeolite.

[Brief description of drawings]

Figure 1: those forming the sample ³ 4.8t / cm 3 as the forming in the sample 2 3.2t / cm ³ as the molding with different pore distribution Sample 1 atmospheric pressure of the sample of molding pressure Figure 2: heat treatment conditions Distributions of samples with different temperatures Sample 1 Reduced at 500 ° C in hydrogen stream Sample 2 Hydrogen / carbon monoxide / steam mixed gas stream 50
Reduced at 0 ℃ Sample 3 Burned at 500 ℃ in hydrogen stream Sample 4 Burned at 250 ℃ in hydrogen stream Fig. 3: Decomposition of linear paraffins in vacuum gas oil

Front page continuation (72) Inventor Masaaki Oba 1-1, Higashi, Tsukuba-shi, Ibaraki Institute of Chemical Technology, Institute of Industrial Technology (72) Kunio Suzuki 1-1-1, East, Tsukuba, Ibaraki Institute of Chemical Technology, Institute of Industrial Technology

Claims (3)

[Claims] 1. A high-performance zeolite catalyst for petroleum reforming, characterized by molding zeolite together with 1 to 500 times its weight of zinc oxide-chromium oxide composite oxide (Zn / Cr atomic ratio = 0.1 to 10). Method. 2. A zinc oxide-chromium oxide composite oxide (Zn / Cr atomic ratio = 0.1 to 10) in an amount of 1 to 500 times by weight that of zeolite and 1 to 500 times by weight of a Group VIb metal or VII of zeolite.
A method for enhancing the functionality of a zeolite catalyst for petroleum reforming, which comprises molding with a Group I metal, a compound thereof, or a mixture thereof. 3. The method according to claim 1, wherein the molding is carried out under pressure.