JPS5856394B2 - Coal liquefaction method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for liquefying coal.

More specifically, the present invention relates to a coal liquefaction method in which an acidic mixed oil is used as a liquefaction solvent together with a specific fraction of aromatic heavy oil when liquefying coal such as non-caking coal or weakly caking coal.

It is already known to liquefy coal and use it as a liquid energy source or as a binder for coke production.

A common method for coal liquefaction involves blending fine coal powder with aromatic heavy oil as a solvent and reacting the mixture at high temperature and pressure in a hydrogen atmosphere in the presence or absence of a catalyst.

However, in conventional methods, the liquefaction efficiency is not always satisfactory due to differences in coal types, etc. Therefore, it is necessary to innovate the liquefaction catalyst, use higher temperatures and pressures, or use large amounts of hydrogen. Ta.

Attempts have also been made to increase the coal liquefaction efficiency by using a mixture of a hydrogen donor solvent such as tetralin, an aromatic solvent, pure phenol, pure P-cresol, etc. as a liquefaction solvent.

However, tetralin is very expensive and it is not advantageous to use it on an industrial scale.

The present invention aims to provide a coal liquefaction method that uses an inexpensive solvent and has good liquefaction efficiency.

While researching solvents suitable for coal liquefaction, the present inventors discovered that the efficiency of coal liquefaction becomes extremely high when a specific fraction of solvent and tar acid are used in combination, and the present invention has been completed.

That is, the present invention provides a method for liquefying coal by heating it together with a solvent under pressure, in the presence or absence of hydrogen, and using a substantially The method is characterized in that a neutral aromatic heavy oil is used as the solvent, and tar acid is blended into the solvent.

The kitchen knife present invention will be explained in detail.

The raw material coal used in the present invention may be coal conventionally used for coal liquefaction.

In other words, any coal with little or no caking content, such as weakly caking coal, non-caking coal, lignite, etc., may be used, but from the economic point of view, it is more advantageous to use lower grade coal such as lignite. be.

However, anthracite is generally not suitable for liquefaction, and anthracite is not preferred in the present invention either.

The above-mentioned coal is used in the same manner as in the conventional liquefaction method, and preferably has a particle size of 28 to 100 mesh or less and is used as a raw material.

The solvent used in the present invention is a substantially neutral aromatic heavy oil having at least 50% by weight of a fraction having a boiling point of 250° C. or higher, preferably 300° C. or higher at normal pressure.

Such heavy oil may be a heavy oil component of the oil obtained during tar distillation in the tar industry, and does not require any special reaction treatment.

Examples of such oils include creosote oil, anthracene oil, pinch oil, and coal-based coker by-product oil.

In addition, aromatic heavy oils generally used as coal liquefaction solvents, such as oil by-produced during coal liquefaction, may be used as long as the fraction thereof falls within the scope of the present invention.

In addition, when there are many low-boiling point fractions, it is possible to use a fraction adjusted to the range of the present invention by appropriately cutting the fraction.

In the present invention, when a substantially neutral aromatic heavy oil having a boiling point lower than 250° C. is used as a solvent, the liquefaction efficiency does not increase, which is not preferable, probably because the oil has a low affinity with coal.

The fraction having a boiling point of 250° C. or higher in the present invention is required to account for 50% by weight or more, preferably 70% by weight or more of the liquefaction solvent, and if it is less than that, the liquefaction efficiency will not increase and is not preferred.

Furthermore, when heavy oil other than aromatic oil is used, the liquefaction efficiency is extremely poor.

The blending amount of the aromatic heavy oil in the present invention depends on the type of coal used, the purpose of the product, etc., but is generally the same as the blending amount of solvent in known coal liquefaction. Although it is about 1 to 10 (weight ratio), coal IKi and solvent 2
~5 (weight ratio) is preferred from the viewpoint of subsequent processing.

In the present invention, tar acid, which can also be called a liquefaction accelerator, is blended in addition to the liquefaction solvent.

The above-mentioned tar acid has a phenolic hydroxyl group attached to an aromatic ring, and examples thereof include phenol, cresol, and xylenol.

These can be used in isolated form, but from the viewpoint of economy, liquefaction efficiency, etc., it is preferable to use them in the form of a tar acid mixture or crude tar acid oil.

The amount of tar acid used is about 5 to 40% by weight, preferably 10 to 30% by weight of the total amount of the above-mentioned solvent and tar acid used.

If the amount of tar acid used is less than 5% of the total amount of the above-mentioned solvent and tar acid used, there will be little effect; There is not much difference in the effect even if it is increased by more than % by weight, and on the contrary, the viscosity of the coal liquefaction product system tends to increase, probably due to the tar acid crystals.

In the present invention, when coal is liquefied using a specific fraction of aromatic heavy oil and tar acid in combination, a known liquefaction method may be used.

That is, fine coal powder is mixed with a specific distillate of aromatic heavy oil as a solvent and tar acid, and then heated under a pressure of several kg/cvt to several tens of kg/cvi, under a hydrogen atmosphere or inert. The coal is liquefied by reacting in an atmosphere at 350 to 450°C for several tens of minutes to several hours.

Further, a catalyst may be added if necessary. It is generally preferable to carry out such reactions under a hydrogen atmosphere.

Although the mechanism of action in the present invention is not clear, it is likely that tar acid has a strong affinity with specific compounds such as oxygen present in coal, and on the other hand, heavy oil of a specific distillate with strong aromaticity is It has strong permeability and affinity for coal micelles, and has a large effect of loosening the binding force of coal micelles, and these effects are thought to further promote coal liquefaction.

Example 1 150g of lignite dried and crushed to less than 28 mesh
The substantially neutral aromatic heavy oil 360P shown in the table and the
90g of tar acid mixed oil (crude tar acid oil) shown in the table was added to the IJ
Prepared in autoclave at 420°C 70kg/crAG
The mixture was reacted for 1 hour under hydrogen pressure.

The amount of autoclave contents obtained here was 410P.

The quinoline dissolved content of the contents was measured, and the coal conversion rate was determined from this to be 97.4%.

The coal conversion rate referred to here is defined as follows.

Example 2 Domestic weakly coking coal was dried and pulverized to 28 mesh or less, and 360 g of the same aromatic heavy oil as in Example 1 and 90 g of tar acid as in Example 1 were added as a solvent to 11 autoclave. The mixture was charged and heated to 390° C. under an inert gas atmosphere, and reacted for 1 hour at the vapor pressure of the contents at that temperature, and the obtained contents were 5911.

The coal conversion rate of this was determined to be 95.1%.

Example 3 The same treatment as in Example 1 was performed except that pure phenol was used as tar acid, and the coal conversion rate was 90%.

Comparative Example 4501 of only the aromatic heavy oil used in Example 1 was blended with 150 g of dried lignite having a mesh size of 28 or less, and the mixture was heated at 390°C 7
The reaction was carried out for 1 hour under a hydrogen pressure of 0 kg/crAG.

The content of the autoclave obtained was 4962, and the coal conversion rate was found to be 68.4%.

Claims (1)

[Claims] 1 When heating coal with a solvent and liquefying it under pressure, in the presence or absence of hydrogen, the boiling point at normal pressure is 250
A coal liquefaction method characterized by using a substantially neutral aromatic heavy oil having a small fraction (50% by weight or more) of 50% by weight or more as the solvent and blending tar acid into the solvent. .