JPS63137754A - Preparation of magnesia-based catalyst for low temperature modification of hydrocarbon - Google Patents

Abstract

PURPOSE:To obtain a catalyst having strength and excellent in the modifying activity of hydrocarbon at low temp., by adding a special binder to a carrier based on high purity magnesia clinker and adding an impregnation and calcination process. CONSTITUTION:The fineness of a magnesia raw material containing 96% or more of MgO and 1% or less of iron oxide is adjusted so as to perfectly pass through a 65-mesh Tyler standard screen, and 1-10wt.% of nickel oxide and 1-7wt.% of a special binder are added to said raw material to prepare a cata lyst base. Herein, as the special binder, three components, that is, starch having a characteristic of gasifying by 99% at 1,000 deg.C, carbonate of MgO or (NH4)2CO3 and Mg chloride or phosphate are used. By adding an impregnation and calcina tion process to the catalyst base after granulation and drying, a catalyst for he low temp. modification of hydrocarbon supporting 2-6wt.% of NiO and 0.2-1.2wt.% of oxide of a rare earth metal and having long life is prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention uses a fine powder of high-purity magnesia krysica as a carrier, adds and mixes 1 to 1 ON of fine powder of nickel oxide, and adds a special binder to this. After kneading, shaping, and drying, the catalyst base is sufficiently sintered by low-temperature firing at 1250 to 1350 degrees Celsius, which is impregnated with a nickel nitrate solution and then calcined to form nickel oxide. ~ 6X carried,
Furthermore, it is impregnated in a solution containing at least 1 m of rare earth elements, and then calcined to support 0.2 to 1.2% of rare earth oxides, increasing strength and improving hydrocarbons at low temperatures. The present invention relates to a method for producing a catalyst with excellent quality and activity.

Conventional technology Generally, heat-resistant nickel catalysts are made of high-purity magnesia (M
Refractory raw materials such as gO) and alumina (A40g) are used. The necessary properties of the refractory raw material include heat resistance and high activity of the refractory raw material itself. It is well known that high purity alumina or high purity magnesia is the most suitable material for these two properties.

Problems to be Solved by the Invention Due to their high melting points, these high-purity raw materials cannot be sintered at low temperatures below 1350 degrees Celsius, and their severe lack of strength makes them difficult to use as catalysts. If the nickel oxide is fired at a temperature of 1,600 degrees or higher, which is completely unusable and where these high-purity raw materials sinter well, the activity of the nickel oxide mixed as a raw material will be completely lost. Additionally, if a few percent of commonly used inorganic sintering agents such as boric acid, alkali, and various glass powders are added, the sintering temperature will be lowered slightly;
At the same time, the heat resistance of the raw material is lowered, and these bonds form a coating on the surface of the nickel oxide, which reduces the activity of the catalyst. Therefore, it has conventionally been considered impossible to produce a catalyst body by a mixed firing method using high-purity magnesia or alumina as a carrier.

As a means to solve the problem, a special binder developed by research and development by the present inventor was used.
By adding 7X, the dry strength of the molded product is significantly increased, and sufficient sintering occurs at low temperature firing of 1250 to 1350°C, resulting in a highly heat resistant, highly active and robust catalyst base. Furthermore, by adding an impregnation calcination step to this, 2 to 6% by weight of nickel oxide and 0.2 to 1.2% by weight of rare earth oxides are supported, allowing for low-temperature reforming of hydrocarbons with a long life. It has now become possible to produce a robust catalyst with low carbon/deposition as a catalyst for use in industrial applications.

The special binder referred to in the BAK of the present invention is basically composed of three components, namely, a mu component, a B component, and a zero component.

Here, component A is starch that has the property of vaporizing 99% at 1000°C, which gives plasticity to MgO, the main raw material of the present invention, and prevents cracks in the undried carrier at temperatures of 60 to 120°C. It is a substance that plays the role of preventing. Component B is Mg carbonate such as Mg00s or (NH4
)t 00s, etc., and is a substance that gives plasticity to MgO and plays the role of preventing cracks in the carrier at temperatures of 800 to 1200°C.

Furthermore, the zero component referred to here is a MR chloride or a component that improves the strength after forming.

According to the present invention, the amount of the special binder made up of component A, component B, and component 0 is 1 to 7X], and depending on the manufacturing conditions of the carrier, component B and component 0 may be one or more of them. You can select and use the above.

The high-purity magnesia mentioned here has an MgO content of 96%.
% or more and the content of iron oxide is IX or less. MgO
If the iron oxide content is less than 96%, the activity and heat resistance of the catalyst will be reduced (due to other impurities). Rounding may increase the precipitation of carbon during reaction use.

! The particle size of the Gnesia raw material was set to 65 mesh according to the Tyler standard clause, and if the particle size was larger than 65 mesh, it was 12.
This is because sufficient sintering cannot be achieved under the firing conditions of 50 to 1350°C.

The reason for limiting the content of nickel oxide to 1 to 10% is 1
If it is less than 10%, sufficient activity cannot be obtained as a catalyst pace, and if it is more than 10%, activity improvement and boost-up are not mutually exclusive.

This is because if the amount is less than this, the catalyst activity will be insufficient, and if it is more than this, there will be a disadvantage of excessive activity and it will not be cost effective.

Example Example 1 and Table 1 compare the effects of using a special binder, which is the main part of the present invention, with those of using a conventional general organic binder.

Example 1 Mixing/kneading Ribbon mixer molding Wet granulation shape/size Pellet φ14mm Firing temperature
1300℃ 4 hours That is, as is clear from Table 1, when comparing prototypes 1 and 2 using the special binder with the comparative example, the strength of the base material and the strength of the fired product are dramatically superior and the running value is shown. ], the effect of the special binder can be clearly seen. However, when the special binder was outside the claimed range of 1-7% and the special binder was 0.5% in 9 prototypes 3-4, the strength was lower than the target, and in 8X, the porosity was higher than the target. It is too large to be suitable as a catalyst base for the present invention. Firing temperature: 1250℃~
The temperature was limited to 1350°C because below 1250°C, the strength would not reach the target value even if a special binder was used, and above 1350°C the activity of the mixed nickel would decrease.

Next, Table 2 shows that all combinations of components A, B, and C of the special binder in the present invention are effective.

The conventional catalyst base has a porosity of 31-33% and a compressive strength of 750.
If Kt/CIA or more, good performance is exhibited, and all of Table 2 satisfy this condition.

The catalyst base prepared by the above method is made to contain nickel nitrate, supported at 2 to 6% by weight as NIO, dried, calcined at 600 to 650°C, and further impregnated with rare earth nitrate. , 0.2 to 1.2 as a rare earth oxide
After being supported by weight%, it is dried and calcined again at 600 to 650°C to remove unnecessary substances other than the heat-resistant substance.

If the supported amount of NiO is less than 2X, the catalyst activity will be insufficient, while if it exceeds 6X, problems such as carbon deposition on the catalyst will occur due to excessive activity, and it will not be cost effective.

If the amount of rare earth oxide supported is less than 0.2%, the effect of adding expensive components will not be exhibited, while if it is more than 12X, the cost will be too high and it will not be economically advantageous.

The rare earths used in this case are lanthanum, cerium, yttrium, etc., and the salts used are nitrates or acetates.

Next, the quality and activity values of various catalysts obtained by subjecting the catalyst base of the present invention to an impregnation and calcining process will be listed.

Example 2 Mixing/kneading Ribbon mixer molding Wet granulation shape/size Pellet φ14mm Firing temperature
Impregnation at 1,300℃ for 4 hours Calcination of nickel nitrate and lanthanum nitrate at 600℃ As shown in Tables 3 and 4, the catalyst of the present invention has higher strength than conventional catalysts (at low temperatures of 650℃ and 700℃). The activity test demonstrated that the produced gas calorie was much lower and that it was an excellent catalyst.After testing the catalyst of the present invention, the reaction tube was removed)
As a result, no powdering due to strength reduction was observed at all, and 9 was observed, whereas powdering of 5(X) or more occurred with the conventional catalyst.

Effects According to the present invention, the produced catalyst for low-temperature reforming of i-gnesian hydrocarbons has high strength, so it is easy to handle when inserting the catalyst into a reaction device, and it is easy to handle during use. As a result, the increase in furnace pressure loss during operation can be reduced. Furthermore, since it is active at low temperatures, thermal energy for maintaining temperature can be saved.

Furthermore, by properly adding rare earth elements, carbon precipitation during the reaction can be suppressed, resulting in sustained and stable activity.

Claims (1)

[Claims] The main material for the carrier is magnesia clisicar with an MgO content of 96% or more and an iron oxide content of 1% or less, which has a particle size that passes through a 65-mesh Tyler standard sieve, and 1 to 10% by weight of nickel oxide. Add and mix, add component A to this,
1 to 7 special binders composed of component B and component C
Add weight%, knead, extract granulate, dry, 1250-1
Calcinate at 350 degrees C to obtain a catalyst base, and impregnate this base with a solution containing nickel nitrate and at least one of rare earth elements to obtain 2 to 6% by weight of NiO and 0.2 to 6% of rare earth element oxide. A method for producing a catalyst for low-temperature reforming of magnesia-based hydrocarbons, which comprises supporting 1.2% by weight and then calcining the catalyst.