JPS63251492A - Production of coke with high tar and gas yields - Google Patents

Abstract

PURPOSE:To prepare coke and recover tar and gas as by-products in high yields, by depolymerizing coal, recovering the low-MW component thus prepd., and carbonizing or carbonizing the low-MW component after molding. CONSTITUTION:Coal is depolymerized at pref. 300-600 deg.C. The depolymerization product is extracted with, e.g., a solvent such as tetrahydrofuran, to recover a low-MW component. This component is carbonized directly or after molding to prepare coke. When coal is directly carbonized according to the conventional process, there occurs depolymerization. However, most of the depolymerization product brings about re-polymerization to prepare coke. This lowers the yields of tar and gas, particularly tar. According to the present process, since the low-MW component prepared by depolymerization of coal is carbonized after recovery of tar and gas, the re-polymerization of the low-MW component can be prevented, which enhances the yields of tar and gas, particularly tar.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing coke, and particularly to a method for producing coke with a high yield of tar and gas as by-products.

[Prior Art] Methods for producing coke from coal include methods such as a room furnace coke production method and a molded coke production method. In any production method, the total amount of by-product tar and gas varies depending on the properties of the coal used, but for example, "Chemistry of Petroleum and Coal" by Takatoroshi Yoshida, Hiroshi Tsukashima, and Sadao Ueno (Kyoritsu Shuppan, 1972) As is clear from Figure 4.24, page 168 (Published in 2010), it is about 20 to 25% by weight of coal. Further, tar accounts for about 3 to 10% of this.

[Problems to be Solved by the Invention] However, tar and gas are useful as fluid energy, chemical raw materials, etc., and the development of a method to further increase the yield of tar and gas by-produced during coke production is expected. However, no effective method has been proposed yet.

Methods to directly liquefy or gasify coal are also being developed, but they require advanced and expensive equipment and, for example, 30 kg/cm2.
The disadvantage is that it requires severe conditions such as high pressure. Therefore, if it is possible to increase the production of tar and gas by adding a simple device to existing coke manufacturing equipment, the effect will be significant.

[Means for Solving the Problems] The present invention is characterized in that the yield of tar and gas is improved by depolymerizing coal, recovering the generated low molecular weight components, and then carbonizing it or carbonizing it after molding. This is a method of producing high coke.

The coal depolymerization treatment method of the present invention includes preheating, co-preheating with additives, and the like.

The treatment temperature for coal depolymerization treatment is 300℃ or higher and 600℃
Less than that is appropriate. This is because coal depolymerization does not occur at temperatures below 300°C, and repolymerization of low molecular weight components produced by depolymerization occurs rapidly at temperatures above 600°C. In addition, when performing co-preheating treatment with a small amount (5 to 30% by weight) of additives, the additives may include aromatic organic compounds such as anthracene, pyrene, fluoranthene, and organic compounds containing aromatic organic compounds. Solvents such as anthracene oil are suitable. Additives having hydrogen-donating properties, such as tetralin, hydrogenated fluoranthene, hydrogenated anthracene oil, etc., and phenols that promote ionic depolymerization are particularly preferred since they increase the yield of tar. In these co-preheating treatments, it is preferable to operate under a pressure of 10 to 25 kg/cm2.

The method for recovering low molecular weight components generated by the depolymerization treatment of coal is to use a solvent normally used for extracting tar-like organic matter, such as benzene, tetrahydrofuran, or absorption oil, or a supercritical gas, such as toluene in a supercritical state. This is an extraction method.

Furthermore, as a carbonization method after depolymerizing coal and recovering the generated low molecular weight components, commonly used methods such as a room furnace coke manufacturing method and a molded coke manufacturing method can be applied. As the coal, ordinary coal used in these methods can be used, but it will be more efficient if additives suitable for the properties of the coal are selected.

[Function] Coal is thought to have a structure in which many unit structures are polymerized. When this is directly carbonized, depolymerization occurs once, but most of it undergoes a repolymerization reaction to become coke, so the yield of tar and gas, especially tar, is low.

In the method of the present invention, the low molecular weight components generated by depolymerization of coal are recovered as tar and gas and then carbonized, so that the low molecular weight components generated by depolymerization are prevented from repolymerizing during carbonization. As a result, the yield of tar and gas, especially tar, can be increased.

[Example] Example 1 Ash content 8.9%, volatile content 27.4%, fixed carbon 63.7%
The blended coal was pulverized to 3n+m or less, placed in a reaction vessel and sealed, and preheated and depolymerized under conditions of a holding temperature of 450°C and a holding time of 7 minutes. This treated product was extracted with tetrahydrofuran to recover low molecular weight components. The extracted residue was carbonized in an indoor coke oven. As a result, the yield of tar was 18.1% by weight, and the total yield of tar and gas was 35.4% by weight. When the coal used in this example was directly carbonized in an indoor coke oven, the yield of tar was 4.1% by weight, and the total yield of tar and dregs was 20.3% by weight. By applying the present invention,
It can be seen that the yield of tar and gas, especially tar, is significantly increased.

Example 2 30% by weight of fluoranthene was added as an additive to 70% by weight of the coal used in Example 1, and the mixture was placed in a reaction vessel and sealed.
Depolymerization treatment was carried out by holding at 80° C. and 12 kg/cm 2 for 12 minutes. This treated product was extracted with benzene to recover low molecular weight components.

This extraction residue was molded at a pressure of 200 kg/cm2,
It was carbonized in a molded coke oven. As a result, the yield of tar was 18.6% by weight, and the total yield of tar and gas was 51%.
It was 6% by weight. Furthermore, when the indirect tensile strength of the produced coke was measured, it was found to be 60 kg/cm2, which was comparable to general metallurgical coke.

In addition, as a recovery process for low molecular weight components, an extraction process using toluene in a supercritical state as a supercritical gas was performed instead of the extraction process using benzene, and the yield of tar was 25.0% by weight. and the total gas yield is 51
．． It was 0% by weight. Furthermore, the indirect tensile strength of the produced coke was measured and found to be 60 kg/cm2.

Example 3 30% by weight of hydrogenated fluoranthene, which has hydrogen-donating properties, was added as an additive to 70% by weight of the coal used in Example 1, and the mixture was placed in a reaction vessel, sealed, and heated at 480°C and 25kg/cm' at 1% by weight.
The depolymerization process was performed by holding for 2 minutes. This treated product was extracted with tetrahydrofuran to recover low molecular weight components. This extracted residue was molded at a pressure of 200 kg/cm 2 and carbonized in a molded coke oven. As a result, the yield of tar was 50.0% by weight, and the total yield of tar and gas was 64.3% by weight. In addition, when the indirect tensile strength of the coke produced was measured, it was 90 kg/cm2,
It was superior to general metallurgical coke.

The amount of hydrogenated fluoranthene added is 10% by weight or 20% by weight.
In terms of weight%, the tar yields are 30% by weight and 4% by weight, respectively.
It became 0% by weight. The indirect tensile strength of each coke was 90 kg/cm2.

[Effects of the Invention] According to the method of the present invention, coal preheating, co-preheating, etc.
Compared to the coal liquefaction method, relatively simple preliminary treatments such as depolymerization treatment under lower pressure and shorter time and recovery treatment of low molecular weight components through extraction etc. are performed, so it is possible to significantly increase the production of tar and gas. Furthermore, existing coke manufacturing equipment can be used as the carbonization equipment for the extraction residue without requiring any special equipment. Therefore, it shows the excellent effect of being able to obtain a large amount of tar and gas from coal without an investment of 5 nods.

Claims (1)

[Claims] A method for producing coke with a high yield of tar and gas, characterized by depolymerizing coal, recovering low molecular weight components produced, and then carbonizing or molding and carbonizing.