JPS59166586A - Method for liquefying coal - Google Patents

Abstract

PURPOSE:To obtain a liquefied material rich in light oil with a low asphaltene content without increasing the amount of generated gas, by liquefying coal in a high activity in the presence of a catalyst obtained by sulfiding an iron compound previously by a specific method. CONSTITUTION:An iron compound, preferably ferrous oxalate, and sulfur are heat-treated at 300-700 deg.C in an inert gaseous atmosphere to prepare a catalyst, which is used to liquefy coal preferably in the presence of hydrogen. The above- mentioned catalyst in an amount of preferably 1-20wt% based on the coal is added thereto and preferably used in the suspended state for reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to coal liquefaction. More specifically, the present invention relates to a method of obtaining a suitable liquefied product by coexisting a specific catalyst when heating coal to liquefy it.

The method of obtaining a liquefied product containing gas and solids by pulverizing all coal, heating it, and adding hydrogen as necessary has been researched for many years.
Many techniques are known. In recent years, due to issues 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 is necessary to add an expensive catalyst or a catalyst that is undesirable from a pollution standpoint, the amount of hydrogen required when coal is heated is large, and carbides are generated 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 ones include chlorides such as zinc chloride, tin chloride, aluminum chloride, nickel chloride, iron chloride, etc., and healthy oxides such as tin sulfide, tin chloride, and iron chloride.
Molybdenum sulfide, lead oxide, silicate steel, zinc sulfide, nickel sulfide, iron sulfide, etc., and oxides include nickel oxide, silica, alumina, iron oxide, cobalt oxide, titanium oxide, etc., and mixtures or The use of red mud and ore has intellectual power.

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

The first group is a compound type, which exhibits excellent catalytic effects on the reactivity of coal liquefaction. Among them, it has been reported that in the melting method used at high concentrations, light oil is produced abundantly, the amount of gas generated is small, and good liquefaction results are shown. However, in putting illegal methods into practical use, there are major restrictions on equipment materials due to the coexistence of hydrogen chloride and gas.

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

It is a group of expensive metals such as Mo, Ni, and W. Although Kone et al.'s catalyst has high hydrogenation activity, it has the disadvantage of being susceptible to deterioration and having a short catalyst life. Also, since the catalyst is expensive,
As in the H-Coal method, a device to keep the catalyst in the reactor, or as in the Dow method, a 6-0 process has been proposed in which all the catalyst is used at a very low concentration and most of it is reused and recycled. ing. However, none of them have reached the stage of completion yet.

The third group is iron compounds. It is inexpensive and is often used as a disposable catalyst. There are many types of iron compounds used, among which iron hydroxide, red mud, iron ore, iron sulfate, etc. are representative. 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.

The present inventors conducted intensive research on the catalytic action of this iron-based catalyst and sulfur, and found that it is possible to use a catalyst from the residue of the coal liquefaction reaction, rather than using a combination of an iron compound and sulfur as a catalyst. It has been discovered that when a certain iron compound is recovered and reused, it always exhibits stable and high catalytic activity, that is, it exhibits liquefaction reaction characteristics with less asphaltene content in light oil and little increase in gas generation.

Based on these findings, we have already proposed various processes for recovering and reusing catalysts, and as a result of our efforts to develop catalysts that exhibit high activity by storing them from the beginning, as will be described later, we have developed various processes for recovering and reusing catalysts. The inventors discovered that the catalyst achieved the desired purpose, leading to the present invention.

That is, in the present invention, when heating coal and liquefying it with or without using hydrogen, iron compounds and sulfur are evaporated into an inert gas.
The present invention provides a method for liquefying coal, which is characterized by using as a catalyst a coal that has been heat-treated at a temperature of 300° C. or more and 700 "C or less in an ambient atmosphere. In a particularly preferred embodiment, the iron compound used is an organic The method of the present invention is provided in which the iron acid is used, and the method of the present invention in which the particle size of @ soot used is 50 μm or less.

Next, the present invention will be explained in detail.

The iron compounds used in the present invention include salts consisting of iron and inorganic acids such as iron oxide, iron sulfate, and iron chloride, iron oxalate, and compounds such as hematite, limonite, and pyrite. It may be a mixture such as iron ore, or it may be a mixture with several types of iron compounds or other substances. Among these, salts consisting of organic acids and iron are preferred as raw materials for carrying out the present invention, and particularly highly active catalysts can be obtained when ferrous oxalate and ferric ammonium oxalate are used as raw materials.

When carrying out total sulfidation treatment of iron compounds (it is better to crush them in advance), it is preferable to crush them to 150μ or less, ideally to 50μ or less, but this is not limited.

In the present invention, sulfur does not necessarily mean pure sulfur, as long as it does not contain anything that could be a catalyst poison. However, if the purity of sulfur is too low,
The higher the purity of sulfur, the better, as it reduces the purity of the product and requires complicated steps to remove impurities. Moreover, the smaller the particle size of this sulfur, the better, and ideally it is 200 mesh or less.

Heat treatment of iron compounds and sulfur is performed in an inert gas atmosphere. Inert gas refers to a gas that does not react with iron compounds or yellow, such as nitrogen, carbon, helium gas, etc.Active gases such as oxygen and chlorine
It's better not to have @t. Although the gas may be used in a flowing state or in a static+h state, it is preferable to heat the gas in a flowing state.

Regarding the relationship 1 between sulfur and sulfur, the atomic ratio (S/Fe) is usually 1.5 or more, preferably 2 to 5.

It is necessary that the reaction temperature be less than 300°C to sulfurize the iron compound.

The reaction time depends on the reaction temperature and the type of iron compound used as a raw material, but it is preferably about several minutes or longer.

The present invention is for liquefying coal using the catalyst prepared by the above method, and will be explained in further detail below.

In the present invention, coal includes anthracite coal, bituminous coal, sublime coal, charcoal, peat, etc. The coal used in the present invention includes:
Bituminous coal, subbituminous coal, and charcoal are more preferred.

Coal is heated at a temperature of 650° C. or higher and 800° C. or lower. When the temperature is low, the liquefaction rate is slow, and when the temperature is high, carbide and gas increase. The temperature is most preferably 400°C or higher and 500'0 or lower.

In the present invention, it is possible to liquefy without using hydrogen, for example, using a pre-hydrogenated solvent, but the liquefaction rate may not improve depending on the conditions.

Therefore, it is common to carry out the liquefaction reaction in the presence of hydrogen, and in this case it is desirable to use the highest possible purity.

The pressure during the hydrogen reaction is preferably 10 kg/α2 or more, and suitably 100 to 600 kg/cIrL2. The hydrogen reaction is complex, and an appropriate pressure is selected depending on the structure of the coal, the slurry solvent to be mixed, etc.

In this invention, liquefaction refers to turning most of the coal into a liquid whose boiling point is above room temperature (approximately 20'O) and below 900°C in terms of normal pressure, but some high-boiling point compounds, lozenges, pastes, It may contain substances such as Therefore, in the present invention, the liquefied material is
Refers to all compounds containing these substances.

When liquefying coal, a solvent may or may not be added, but generally the weight ratio to the coal is 100 to 40.
Add zero coefficient and run.

The preferred solvent used here is liquefied coal oil or hydrogenated oil of liquefied oil, and aromatic hydrocarbons, aliphatic hydrocarbons, acidic oils, base oils, sulfur compounds, etc. are used.

Mixed oils containing these, such as creosote oil and anthracene oil, petroleum fractions, etc. may also be used. The boiling point of the solvent is preferably in the range of 150° C. or higher and up to 600° C. under normal pressure.

Furthermore, the weight ratio of the catalyst added to the coal during the coal liquefaction reaction may be anywhere from 0.01 to 60, but it is most preferably 1 to 20%.

Further, the catalyst of the present invention is used in the reaction in a suspended state. The reaction can be carried out either batchwise or continuously; industrially, the catalyst, coal, and solvent are mixed, preheated under hydrogen pressure, and then continuously fed into a reactor such as a tank or bubble column. However, it is also possible to extract the catalyst continuously, separate it into gas, oil, and insoluble components, and if necessary, recycle part of the oil as a circulating solvent, and separate and recover the catalyst from the insoluble components for reuse.

In addition, when the coal liquefaction reaction is performed using the catalyst of the present invention,
At normal pressure, the amount of light oil with a boiling point of 600° C. or less increases, and conversely the amount of asphaltenes and dereasphaltenes decreases. On the other hand, the amount of gas generated hardly increases.

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

By the way, the surface area of crushed natural pyrite of 200 mesh or less (40.1 to 5 rn"/9, at most 10 m
2/ji or less, whereas the catalyst prepared by the method of the present invention has a diameter of 60 to 200 m279. Most of the catalysts prepared by the method of the present invention have a small particle size of 0.1 to 10μ, and at most 50μ or less.

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

As described above, the feature of the present invention is to use a catalyst that has undergone A''IJ in advance, and compared to the method of simply supplying an iron compound and sulfur to the reaction system as a catalyst, it achieves significantly superior coal liquefaction performance. show.

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these examples.

Example 1 A well-mixed mixture of commercially available oxalic acid sulfur powder and 6 times molar bone sulfur powder was placed in a magnetic container placed in a quartz lath reaction tube, set in an electric furnace, and heated with nitrogen. Gas was passed through the reactor, and the temperature was gradually raised to 450° C. without evaporating water. After reacting for 60 minutes, the reactor was cooled and the product was taken out.

FIG. 1 shows a comparison of the coal liquefaction reaction results between the catalyst thus prepared and other typical iron-based compound catalysts.

Figure 1 ( is the result of evaluating the activity in an autoclave of 0.51. Illinois Nα6 coal was used as the coal, the hydrogen charging pressure was 80 kg//crn, and the pressure at the reaction temperature was about 150 C), reaction time 60 minutes, reaction temperature 4
The liquefaction reaction was carried out at 60°C. The amount of catalyst used was 10% by weight of iron electrodeposition based on 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 in FIG. 1 is the weight fraction of the hexane soluble fraction extracted with respect to the total oil, and can be considered as a measure of the degree of hydrogenation. Here, the total oil refers to the total weight of 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 light oil referred to herein refers to a substance having a C5 or higher temperature, such as hexane, and having a boiling point of 3[]0° C. or lower at normal pressure.

This figure slopes upward to the right as liquefaction progresses toward lighter weight, which can serve as a measure of catalytic activity.

In the figure, (w, ■ and ■ indicate the results of reactions using the following catalysts, respectively.

(2): Mineral pyrite (2): Electrolyzed chichi powder + sulfur (2) Catalyst prepared by the method of the present invention The mineral pyrite (2) above is pyrite produced at the Tanahara mine in the Okayama region, which has been ground to 200 mesh or less. (2) The melted iron powder is commercially available melted iron powder, and has a particle size of 325 mesh or less. The amount of sulfur added at this time was equal to the amount of sulfur.

What is clear from Figure 1 is that the prepared catalyst of ld and This indicates activity.

FIG. 2 shows the particle size distribution of these three types of catalysts. It is obvious that the prepared catalyst is extremely grainy.

Example 2 Using the same method as in Example 1 as a total raw material for ferrous oxalate?
Using a catalyst manufactured by A and Australian lignite A, liquefaction was carried out in a 0.57 autoclave.

The hydrogen charging pressure is 160 KgA''.The reaction temperature is 4
The reaction time at 60° C. is 60 minutes. The amount of soot added is 10 times the weight of anhydrous ash-free charcoal. The solvent used was decrystallized anthracene oil, and 2
Double parts by weight were used.

The results of the experiment conducted under the above conditions are shown in Table 1 and FIG. 6.

Table 1 (Margin below) The symbols in Fig. 6 are as follows.

0. (), : Organic gas N-oi, 1: C5~b, p 200℃ oil F
-1: b, p Oil at 200'O' to roooof, c F2: b, p Oil at 300°C to 6400°C H-oil: b, p At 340°C and hexane town waste fraction A: Asphaltene and filtrate 0 rares faltentea is a hexane insoluble matter and TE (F insoluble matter C:
Organic substance and T'HF insoluble substance B, ()・:By-gas From this result, the generation of organic gas and the appetizers are not so bad, and the formation of light oil such as N oil and F-1 oil. It can be seen that the presently prepared media exhibits ideal catalytic activity in that the amount of asphaltenes and dereasphaltenes are greatly reduced.

[Brief explanation of the drawing]

FIG. 1e shows the results of a coal liquefaction reaction using the catalyst according to the present invention in Example 1 and other representative catalysts. Figure 2 (L'i) is a diagram showing the particle size distribution of the above catalyst. The holo diagram shows the composition of the coal liquefaction product in Example 2 when the catalyst of the present invention was used and when another catalyst was used. This figure shows a comparison with the case where the patent applicant was Asahi Kasei Kogyo Co., Ltd. Figure 1

Claims (1)

[Claims] 1. When coal is heated and liquefied with or without hydrogen, iron compounds and sulfur are heat-treated in an inert gas atmosphere at a temperature of 3000 to 700°C. Coal liquefaction method 2, characterized in that the iron compound used is an organic acid iron, characterized in that the iron compound used is an organic acid iron, 36. Coal liquefaction method according to claim 1, characterized in that the particle size is 50μ or less