JPS5846280B2 - Coal hydrogenation and liquefaction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for hydrogenating and liquefying coal, and more particularly to a method for hydrogenating coal in the presence of a disubstituted dithiocarbamate metal salt.

Conventionally, the methods for converting coal into liquid hydrocarbons are (1)
It is broadly classified into direct hydrogenation method, (2) solvent extraction method, and (3) synthesis method.

Method (1) involves mixing coal with an appropriate solvent and using a catalyst to hydrocrack the coal under high temperature and high strain conditions, but it has the disadvantage of high equipment costs due to the harsh reaction conditions. .

(2) is a method to extract and decompose coal mixed with a solvent in the presence of molecular hydrogen at high temperature and medium pressure to obtain solvent-refined coal or a liquid product, and the liquid product is the main product in large quantities. If you want to obtain this, you must choose a type of coal that contains ash that has a catalytic effect, and you are limited by the raw material coal.

In addition, (3) is the CO2H obtained by once gasifying coal.
2. This is a method of converting synthesis gas into liquid hydrocarbons using an appropriate catalyst, and as it involves many steps, it is inefficient and uneconomical.

Therefore, the present invention has been made in consideration of the current situation, and uses coal that has characteristics such as a high yield of liquid products, especially hexane-soluble oil components, and the ability to use mild reaction conditions. A hydrogenation and liquefaction method is provided.

That is, in the present invention, oil slurry of powdered coal is prepared by the following general formula (
This is a method for hydrogenating and liquefying coal in which hydrogenation is carried out in the presence of an N,N-disubstituted dithiocarbamate metal salt represented by I).

Here, in the above formula (1), R represents an alkyl group having 1 to 15 carbon atoms or a phenyl group having an alkyl side chain having 1 to 15 carbon atoms, and M is titanium, iron, nickel, zinc, molybdenum, cadmium. It is a divalent metal selected from the group consisting of , tin, tungsten and lead.

The amount of the substituted dithiocarbamate metal salt added to the coal slurry is usually 1:9 in terms of anhydrous ash-free charcoal of raw coal.
per mole.

If the amount of the disubstituted carbamic acid metal salt added is less than 10-5 mol, the yield of the liquid product will drop significantly, which is undesirable, and if it is more than 10-1 mol, there will be almost no increase in the yield of the liquid product. You won't be able to see it.

Note that the liquid product refers to asphaltene that is insoluble in hexane and soluble in benzene, and oil that is soluble in hexane.

In the present invention, raw coal is used in the form of slurry.

In this case, the coal used is usually pulverized coal with particles smaller than 100 mesh, and the slurry solvent is usually aromatic oil obtained by coal liquefaction, such as anthracene oil, but is not limited thereto. .

Further, the coal concentration in the slurry can be selected as appropriate; for example, the coal concentration condition of 20 to 50% by weight is generally I
This will be adopted.

The hydrogenation reaction temperature is selected to be a temperature at which the raw coal undergoes thermal decomposition and hydrogenolysis reactions, and is usually 350 to 500'C1, preferably 400 to 450C.

If the reaction temperature is below 350° C., the thermal decomposition and hydrogenolysis of the raw coal will not proceed sufficiently, and therefore the yield of the liquid product will be low.

On the other hand, a temperature of 500° C. or higher is not preferable because the yield of gaseous products increases and the yield of liquid products decreases.

The reaction time, that is, the residence time in the reactor can be selected as appropriate, but is usually 30 minutes to 1 hour.

Although the reaction pressure varies depending on the properties of the required product and the type of slurry solvent, a range of 50 to 500 atmospheres is usually selected to obtain a satisfactory yield of the liquid product.

Further, the present invention is not limited to the type of raw coal, and bituminous coal, lignite, lignite, etc. can be widely used.

Next, the present invention will be considered from the viewpoint of the reaction mechanism.

The reaction of hydrogenating a coal slurry to obtain a liquid product is usually considered to be radical.

That is, free radicals are first generated by thermal decomposition of coal.

These free radicals are stabilized by bonding with molecular hydrogen or hydrogen supplied from a solvent, resulting in a liquid product with a lower molecular weight than raw coal.

The degree of molecular weight reduction varies depending on the presence or absence of a hydrogenolysis catalyst, its type, reaction pressure, etc., but the liquid product is further subjected to hydrogenolysis to further reduce its molecular weight.

On the other hand, since the above free radicals are highly reactive,
If stabilization by molecular hydrogen or hydrogen provided by a solvent does not proceed smoothly, the free radicals undergo a polycondensation reaction and become polymerized again.

The present invention aims to improve the yield of liquid products by preventing the above-mentioned polycondensation reaction which is inconvenient for the coal liquefaction reaction. It is thought that the free radicals generated by this are stabilized.

That is, the disubstituted dithiocarbamate metal salt can act with free radicals, quickly stabilize them, prevent polymerization due to polycondensation, and enhance the quality of the liquid product.

In addition, in the present invention, since the disubstituted dithiocarbamate metal salt acts in the same way as hydrogen as a free radical stabilizer, there is no need to increase the hydrogen pressure or increase the hydrogen supply ability of the slurry solvent, which was previously the case. Comparatively milder reaction conditions can be adopted.

According to the present invention, coal is hydrogenated and liquefied using N.

Since this is carried out in the presence of N-disubstituted dithiocarbamate metal salts, the yield of liquid products, especially hexane-soluble oils, is significantly increased compared to when such dithiocarbamate metal salts are not used. and seven can be done.

Furthermore, the amount of the disubstituted dithiocarbamate metal salt used in the present invention is extremely small at 10-5 to 9 in 10-1 mol/(calculated as anhydrous ash-free charcoal), and such metal salt can be easily prepared. Since it can be obtained or synthesized, it does not increase the cost of liquid products.

Furthermore, since the present invention uses a disubstituted dithiocarbamate metal salt, milder reaction conditions can be employed compared to the case where such a metal salt is not used, and the equipment cost can be reduced as much as possible.

Hereinafter, the present invention will be explained in more detail based on Examples.

Example 1 Taihei Seisei (sub-bituminous coal), which has been crushed in advance to 100 meshes or less, and anthracene oil are mixed in a slurry adjustment tank,
A slurry with a coal concentration of 30% by weight was prepared.

Zinc dipentyl dithiocarbamate (molecular weight 529) was added to this coal slurry in an amount of 8.4 x 10-' mole per 1 kg of coal (calculated as anhydrous ash-free charcoal) and mixed.

The coal slurry was then pumped at a feed rate of 320 F/f, mixed with hydrogen at a flow rate of 254 Nl/H, and heated to 100'C in a preheater.

The mixture of coal slurry and hydrogen coming out of the preheater was then introduced into a seed reactor with an internal volume of 11, at a temperature of 430°C and a pressure of 1
The reaction was carried out under conditions of 0.00 atm.

After cooling the mixture of products and hydrogen from the reactor to 100°C, it is separated into gas and solids by a high-temperature separator and a low-temperature receiver.
A liquid product separated.

Product yields are shown in Table 1.

Comparative Example 1 An experiment was conducted under the same conditions as in Example 1 except that zinc dipentyl dithiocarbamate was not used.

The results are shown in Table 1.

As is clear from the comparison between Example 1 and Comparative Example 1, the effect of zinc dipentyl dithiocarbamate is remarkable; in Example 1, the yield of the liquid product was increased by about 10%, and in particular the hexane-soluble oil The yield for this sample is about twice as high as that of Comparative Example 1.

Example 2 Reaction temperature: 450°C, reaction pressure: 300 atm, amount of zinc dipentyl dithiocarbamate added: 5.0 x 10-3 mol/
A liquefaction experiment of Taihei Seisei was conducted in accordance with Example 1 under the conditions of kg coal (calculated as anhydrous ash-free coal).

The results are shown in Table 1.

Comparative Example 2 An experiment was conducted under the same conditions as in Example 2, except that zinc dipentyl dithiocarbamate was not used.

The results are shown in Table 1.

As is clear from the comparison between Example 2 and Comparative Example 2, the yield of the liquid product in Example 2 is about 10% higher, and the yield of the hexane-soluble oil component is about 1570 times higher.

Example 3 Reaction temperature: 430°C, reaction pressure cuff: 0 atm, amount of zinc dibentyldithiocarbamate added: 2.4 x 10-” mol/
An experiment was conducted in the same manner as in Example 1, except that kg coal (calculated as anhydrous ash-free coal) was used.

As is clear from the comparison between Example 3 and Comparative Example 1,
In Example 3, although the reaction top was further lowered by 30 atmospheres, a liquid product almost the same as that in Comparative Example 1 was obtained, and there was almost no difference in liquid product yield, and dipentyldithiocarbamic acid The effect of easing reaction conditions by zinc can be clearly understood.

Example 4 An experiment was conducted under the same conditions as in Example 1, except that 1.2×10 moles of zinc diethyldithiocarbamate were added.

The results are shown in Table 1. In this Example 4, the yield of the liquid product was about 10% higher than in Comparative Example 1, and in particular, the yield of hexane-soluble oil was about twice as high as in Example 4, and the yield of diethyldithiocarbamic acid was about twice as high. The effect of adding zinc is remarkable.

Example 5 Nickel dill-tolyldithiocarbamate 8.4X1
Hydrogenation and liquefaction were carried out under the same conditions as in Example 1, except that 0-'mol was added.

The results are shown in Table 1.

As is clear from the comparison with the results of Comparative Example 1, the liquid product yield of Example 5 was also about 9% higher, and the oil fraction yield was also about 15% higher.

Example 6 Under the same reaction conditions as in Example 1, the yield of a liquid product was investigated when the amount of zinc dipentyl dithiocarbamate added was varied.

The results are shown in Figure 1.

As is clear from Fig. 1, the practical amount of zinc dipentyl dithiocarbamate added is in the range of 10-5 to 10-' mol, and even if 10-1 mol or more is added, the yield of the liquid product is no longer high. Almost no increase.

Example 7 In Example 1, the relationship between changes in reaction temperature and liquid product yield was studied.

The results are shown in Figure 2.

As shown in FIG. 2, in the present invention, a reaction temperature of 350°C to 500°C is usually employed.

Example 8 A study was conducted under the same conditions as in Example 1 except that lead diethyldithiocarbamate, cadmium, tin, and iron were used as additives and the amounts added were changed.

The results are shown in Table 2. Furthermore, molybdenum, tungsten, and titanium salts of diethyldithiocarbamic acid were also investigated, but almost the same results were obtained.

Example 9 An experiment was conducted under the same conditions as in Example 1 except that zinc diisooctyldithiocarbamate was used as an additive.

The results are shown in Table 2. As is clear from the comparison with Comparative Example 1, the liquid product yield is about 6% higher, and the oil yield is also about 12% higher.

Example 10 Seven experiments were conducted under the same conditions as in Example 1 except that zinc dipentadecyldithiocarbamate was used as an additive.

The results are shown in Table 2. As is clear from the comparison with Comparative Example 1, the liquid product yield is about 4% higher, and the oil yield is also about 7% higher.

Example 11 An experiment was conducted under the same conditions as in Example 1, except that zinc dibentylphenyldithiocarbamate was used as an additive.

The results are shown in Table 2. From the comparison with Comparative Example 1, it is clear that the yield of liquid product increased by about 8% and the yield of oil component increased by about 12%.

Example 12 An experiment was conducted under the same conditions as in Example 1 except that zinc dipentadecylphenyldithiocarbamate was used as an additive.

As is clear from the comparison with Comparative Example 1, the yield of liquid product is about 3% higher, and the yield of oil component is also about 5% higher.

[Brief explanation of the drawings] Figure 1 is a diagram showing the relationship between the amount of zinc dibentyldithiocarbamate added and the liquid product yield, and Figure 2 is a diagram showing the relationship between the reaction temperature and the liquid product yield. It is.

Claims (1)

[Scope of Claims] 1. A method for hydrogenating and liquefying coal, which comprises hydrogenating an oil slurry of powdered coal in the presence of an N,N-disubstituted dithiocarbamate metal salt represented by the following general formula (1). In formula I, R represents an alkyl group having 1 to 15 carbon atoms or a phenyl group having an alkyl side chain having 1 to 15 carbon atoms, and M is titanium, iron, nickel, zinc, molybdenum, cadmium, tin, or tungsten. It is a divalent metal selected from the group consisting of lead and lead.