JPS6121731A - Preparation of coal liquefying catalyst - Google Patents

Abstract

PURPOSE:To obtain a highly active fine coal liquefying catalyst, by mixing sulfur with the solid separated from a slurry mixture consisting of a sulfur ion- containing alkaline aqueous solution and an iron ion-containing acidic aqueous solution before reacting both of them at 200-700 deg.C. CONSTITUTION:A sulfur ion-containing alkaline aqueous solution containing sodium sulfide, ammonium sulfide or potassium sulfide in concn. of 0.1-4mol as a sulfur ion is prepared while an iron ion-containing acidic aqueous solution containing iron acetate, iron sulfate or iron nitrate in concn. of 0.1-4mol as an iron ion and adjusted to pH 2-7 is prepared and both solution are mixed to form a slurry. From this slurry, a fine solid with a particle size of 0.5-2mum is obtained by solid-liquid separation and sulfur is mixed with said solid while the resulting mixture is reacted at 200-700 deg.C to prepare a coal liquefying catalyst.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for producing a catalyst for coal liquefaction.

(Prior art) The method of obtaining a liquefied product containing gas and solids by crushing and heating coal and adding hydrogen as necessary has been researched for many years.
Many techniques are known. In recent years, due to problems such as fuel oil resources and the diversification of chemical products, the development of coal liquefaction technology has been very active, and many new technologies are being developed.

However, there are still many problems in order to efficiently obtain high-quality fuel oil, gasoline, or chemical feedstock oil. For example, it required the addition of expensive or pollutantly undesirable catalysts), the large amount of hydrogen required to liquefy the coal, and the formation of char during the reaction.

Among them, the reaction conditions in the coal reactor, especially the selection of the catalyst, are one of the important factors for determining the quality of liquefied oil. For this reason, a wide variety of catalysts with different chemical species and physical shapes, including methods of addition, have been developed.

There are a large number of catalysts for coal liquefaction that have been known in the past, but typical chlorides include zinc chloride, tin chloride, aluminum chloride, nickel chloride, iron chloride, etc., and sulfides include tin sulfide, molybdenum sulfide, and sulfide. Lead, copper sulfide, zinc sulfide, nickel sulfide, iron sulfide, etc.; oxides include nickel oxide, silica, alumina, iron oxide, cobalt oxide, titanium oxide, etc.; and mixtures thereof, red mud, ores, etc. is known to be used.

The above catalyst groups can be roughly divided into three groups.

The first group is chloride-based, which exhibits excellent catalytic effects in coal liquefaction reactions. Among them, it has been reported that in the molten salt method used at high concentrations, light oil is produced abundantly, the amount of gas generated is small, and good liquefaction results are shown. However, when water droplets are put into practical use, hydrogen chloride gas coexists, which imposes major restrictions on the material of the equipment.

The second group is Co, which is often used in heavy oil hydrogenation.

A group of expensive metals such as Mo, Ni, and W. Although these catalysts have high hydrogenation activity, they have the drawbacks of being susceptible to poisoning and having a short catalyst life. Well, since the catalyst is expensive, there are ways to keep the catalyst in the reactor, such as in the boiling bed of the H-Coal method, or to use the catalyst at a very low concentration, and reuse most of it, as in the Dow method. Circulating processes and the like have been proposed. However, none of them have reached the stage of completion yet.

The third group is iron compounds. This is inexpensive and is often used as a disposable catalyst. There are many types of iron compounds used, but the most representative ones include iron hydroxide, red mud, iron ore, and iron sulfate. The activity of these iron compounds increases dramatically when sulfur coexists. Therefore, it has been proposed to add sulfur to coal that has a low sulfur content.

Furthermore, the catalytic activity of natural pyrite (Fe51; pyrite) is well known, and various methods for producing synthetic pyrite have been studied.

Conventionally, such a catalyst has been developed by reacting an aqueous sodium sulfide solution and an aqueous iron sulfate solution at room temperature or lower, and then removing the remaining Na+ dissolved in the water by total filtration or centrifugation of the resulting slurry. , Fe”, S
After removing O4''k and desalting, sulfur powder is added to the remaining slurry and reacted at approximately 80C for 2 to 6 days. The resulting slurry is cooled, filtered or centrifuged, and unreacted iron sulfide is washed with hydrochloric acid. The substance after removing residual sulfur with carbon disulfide or the like was used as a catalyst for coal liquefaction.

(For example, Sampuia National Laboratory in the United States
The wet synthesis method shown above (Energy Report No. 80-2795) has a very sharp particle size distribution and can easily produce fine particles with an average particle size of 1 to 5 μm, but the overall reaction time is short. The disadvantage is that the length is very long and production efficiency is poor.

On the other hand, the dry synthesis method shown by the present inventors (%
No. 8548, Japanese Patent Application No. 58-39177) have the advantage of being able to prepare pyrite in a few hours, but on the other hand, why do the particle size distributions of the 41-ke products tend to be broad?
Another disadvantage is that in order to produce fine pyrite, a sufficiently fine raw material must be prepared.

(Problems to be Solved by the Invention) As mentioned above, the conventional wet synthesis method and dry synthesis method each have advantages and disadvantages, and it is desired that a method that combines the advantages of both methods and eliminates the disadvantages be developed. It was rare.

(Problem't - Means for Solving) The present inventors conducted research in accordance with the above request, and found that the solid content was solidified by a very small force of 0.5 to 2 μ generated in the first stage reaction. After liquid separation, this solid partial pressure sulfur is mixed,
It was discovered that the reaction could be completed in an extremely short time of 10 minutes to 2 hours by carrying out the reaction at a temperature of 200C or more and less than 700C, and it combines the advantages of both wet and dry methods.
We have completed a method that eliminates the drawbacks.

That is, in the present invention, an alkaline aqueous solution containing sulfur ions and an acidic aqueous solution containing iron ions are mixed, the resulting slurry is subjected to solid-liquid separation, sulfur is mixed with the obtained solid content, and a The present invention provides a method for producing a catalyst for coal liquefaction, which is characterized in that the reaction is carried out at a temperature lower than that of the present invention.

In the present invention, the alkaline aqueous solution containing sulfur ions is, for example, an aqueous solution of sodium sulfide, ammonium sulfide, potassium sulfide, calcium sulfide, etc., or a solution obtained by absorbing hydrogen sulfide gas into an alkaline aqueous solution. These aqueous solutions are generally used at a sulfur ion concentration of 0.1 to 4 molar, depending on the solubility of the salt and the temperature. In addition, the purity of these reagents is sufficient at the level of industrial chemicals,
Alternatively, an aqueous solution of a salt consisting of sulfur and alkali produced as a by-product in the process of treating sulfur and arsenic gas may be used as is. For SaraK, you can use a mixture of alkalis rather than just one type of alkali.

The acidic aqueous solution containing iron ions is, for example, an aqueous solution of iron acetate, iron sulfate, iron nitrate, iron oxalate, iron chloride, or the like, or a solution in which iron is dissolved in an inorganic or organic acid. Of the iron ions, the difference in b between ferrous and ferric ions may be fine, but if forced, ferrous ions are preferred. However, these salts may be industrial reagents or may be by-products from other processes. Furthermore, iron ore dissolved in acid may be used, and it is also desirable to use a mixture of various iron salts. The concentration of iron ions in this aqueous solution is also generally preferably used within a range of 0.1 to 4 mol. If the concentration of these aqueous solutions is too thin, it is economically disadvantageous, and if the concentration is too thick, the temperature must be raised more than necessary to increase solubility. In the reaction between an alkaline aqueous solution containing sulfur ions and an acidic aqueous solution containing iron ions (hereinafter referred to as the one-stage reaction), the reaction is approximately equimolar between sulfur ions and iron ions, but the pH of the solution after the reaction is 2 or more and less than 7. The mixing ratio of both is preferably adjusted to be 4 or more and 6 or less.

This reaction progresses instantaneously and is black with an average particle size of 0.5 to 2.
Very small particles are generated. Next, the solid-liquid separation operation of the slurry thus generated is performed using one or two known solid-liquid separation methods such as filtration, centrifugation, gravity sedimentation, and hydrocyclone. The above methods can be implemented in combination. However, during this solid-liquid separation process, it is preferable that alkali ions and acid ions dissolved in the liquid be removed as much as possible. For this purpose, it is also effective to use an ultrafiltration membrane or the like. If the resulting solid content has a particularly high moisture content, heat may be applied to evaporate the moisture.

Sulfur may be in powder or liquid form. When the obtained solid content is mixed with sulfur, the mixing ratio is not particularly limited, but it is preferable that the atomic ratio of sulfur to iron in the solid content is 0.
．． Mix at a ratio of 5 to 5.

If the reaction temperature is less than 200C, the reaction rate will be slow, and if the reaction temperature is less than 700C.
Since iron cannot take a sufficiently sulfurized form if the iron is above, it is necessary to have a temperature of 200C or more and less than 700C, preferably 200C or more and less than 500C.

The reaction time varies depending on the reaction temperature and the type of iron compound used as a raw material, but is several minutes or more, preferably 10 minutes to 2 minutes.
It takes about an hour.

In carrying out the invention, it is preferred that all steps be carried out in an atmosphere of very low oxygen concentration.

For this purpose, it is preferable to carry out the process in an inert gas atmosphere such as nitrogen or argon gas. This is because both the precipitate produced during the process and the final product are susceptible to oxidation.

The effect of the present invention is that a highly active and very fine catalyst can be produced easily and stably in a short reaction time, which increases the productivity of the catalyst and has a large economic effect.

The present invention is characterized by a method for preparing iron sulfide, which shows a similar pattern in X-ray diffraction, etc., compared to natural iron sulfides such as ironite, marcasite, and pyrrhotite. However, as shown in the Examples, the activity of the catalyst involved in the coal liquefaction reaction is several times higher in the catalyst according to the present invention. Although the details of this reason are unknown, it is presumed that it is probably due to the surface area and surface condition LIK.

By the way, the surface area of crushed natural pyrite of 200 mesh or less is 0.1 to 5771'/l, at most 10 mesh/y.
- The catalyst prepared by the method of the present invention has 3
It is 0 to 200 m'/y. Further, most of the catalysts prepared by the method of the present invention have a small particle size of 0.05 to 5 μm.

Unlike when a general iron compound is used as a catalyst, the coal liquefaction reaction using the catalyst of the present invention does not require the separate addition of sulfur.

When a catalyst prepared in advance as described above is used, coal liquefaction performance is far superior to that of a method in which an iron compound and sulfur are simply supplied to the reaction system as a catalyst.

(Effects of the Invention) The effects of the present invention are that a highly active and extremely fine catalyst can be stably produced easily and in a short reaction time;
It increases catalyst productivity and has great economic effects.

(Examples) Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. Dissolved in 4 t of distilled water. Further, sodium sulfide trihydrate 5201 was mixed with 4 tons of distilled water and heated to 50C to dissolve it.

These two liquids were completely mixed, the resulting slurry was filtered and washed with water, and the resulting solid content was mixed with sulfur powder at 240° C. This was placed in a quartz tube and heated at 110 C while flowing nitrogen gas.
After drying for an hour, the temperature was raised to 300C and heating was performed for 1 hour. All intermediate filtration, washing, etc. were performed in a glove box with nitrogen gas flowing through it.

The results of the coal liquefaction reaction between the thus prepared catalyst of the present invention and other typical iron-based compound catalysts are compared and shown in the drawing.

The figure shows the results of activity evaluation in a 0.5 t autoclave. Illinois A6 coal was used as the coal, and the hydrogen charging pressure was 80 kg/d (the pressure at the reaction temperature was approximately 150 kg/d).
kg/all), reaction time 30 minutes, reaction temperature 460
The liquefaction reaction was carried out at C. The amount of catalyst used was 10 iron weight per anhydrous ash-free coal.

Decrystallized anthracene oil was used as a solvent, and twice the amount by weight of anhydrous ash-free charcoal was added.

The horizontal axis of the drawing represents the weight fraction of the hexane soluble fraction extracted with respect to the total oil, which can be considered as a measure of the degree of hydrogenation. Here, the total oil refers to the total weight of the hexane soluble fraction extracted, asphaltenes, and pre-asphaltenes. The vertical axis indicates the weight fraction of the light oil produced relative to the charged anhydrous ash-free coal, which is considered as a measure of the degree of hydrocracking. The term "light oil" as used herein refers to a substance having a carbon number of 5 or more, such as hexafluoride, and having a boiling point of 300 c or less at normal pressure.

In this drawing, when liquefaction progresses toward lightening, the upper right corner becomes lume,
As a result, it can serve as a measure of catalytic activity.

In the drawings, ■, ■, and ■ indicate the reaction results using the following catalysts, respectively.

■Catalyst prepared by the method of the present invention Pyrite produced from Mt. 8 is ground to 200 mesh or less. It is a fine powder of fi, 325 mesh or less. The amount of sulfur added at this time was equimolar to that of iron.

What is clear from the drawings is that the catalyst prepared according to the present invention in (1) has a higher degree of hydrogenation and a higher degree of hydrogenolysis than other catalysts, and exhibits excellent activity.

[Brief explanation of drawings]

The drawing is a chart showing a comparison of the activity in the coal liquefaction reaction of the catalyst used in the present invention and other catalysts. 0 20 40 60
80 to. To ``+ Punka 5 autopsy / small oil (%) 柟

Claims (1)

[Claims] An alkaline aqueous solution containing sulfur ions and an acidic aqueous solution containing iron ions are mixed, the resulting slurry is subjected to solid-liquid separation, sulfur is mixed with the obtained solid content, and the mixture is heated at a temperature of 200°C or more and less than 700°C. A method for producing a catalyst for coal liquefaction, which is characterized by causing a reaction.