JPH0488085A - Production of rapidly thermally coal-decomposed char - Google Patents

Abstract

PURPOSE:To efficiently produce rapidly thermally decomposed char by indirectly cooling the inside of a char pot to a specific temperature by a liquid to condense tar on the char in a process for rapidly decomposing coal. CONSTITUTION:Coal is charged into a thermal decomposition reactor 1 with a high temperature gas from a circulation gas heater 5. In the thermal decomposition reactor 1 a gas component, a tar component and a char component are produced. The gas and tar components are produced in gas states and the char component is in a solid state. The products are cooled with a heat- recovering device 2 and subsequently fed into a char pot 3 in the hot state of 250 deg.C wherein the gas and tar components are fed in the gas states and the tar is fed into the solid state. The gas and tar components in the gas states are thereby separated from the char in the solid state in the char pot.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is directed to a process in which coal is thermally decomposed to obtain the volatile matter in the coal as a gas and a liquid substance, in which a solid residue (char) other than the volatile matter is The present invention relates to a method for producing coal rapid pyrolysis char, in which tar is attached to and condensed on the char in a coal rapid pyrolysis process for use as a blending material for blast furnace coke.

[Prior Art] The process itself of rapidly pyrolyzing coal to obtain the volatile matter in the coal as gas and liquid substances is disclosed in Japanese Patent Application Laid-Open No. 1-11344.
It is disclosed in Publication No. 11. Rapid pyrolysis of coal produces char, tar, and gas. The gas in the product is circulated with sensible heat recovery, and the char is recovered as hot char at 250°C in a charpot. Thereafter, the target substance, tar, is condensed at low temperatures and recovered.

Tar obtained from rapid coal pyrolysis has high added value as a raw material for chemical products.

On the other hand, since residual char is inert like coke powder and coal gasified char, the only way to use it is to burn it. Establishing a method for utilizing residual char is a very important issue in terms of practical application of the coal rapid pyrolysis process.

By the way, as an example of the use of inert substances such as coke powder and coal gasified char, it is considered to be a blended raw material for blast furnace coke as described in JP-A-52-112602. In this case, coke powder and coal gasified char are finely pulverized to increase the active surface area, and impregnated with sticky aromatic solids to increase affinity with coal.

[Problems to be Solved by the Invention] However, considering the steps of pulverization and impregnation of aromatic bituminous material, extra equipment is required and costs increase.

When the present inventors took a look at the properties of the residual char obtained from rapid coal pyrolysis, it was found that the particle size is small, so pulverization is not necessary when used as a blending material for blast furnace coke. Furthermore, considering the coal rapid pyrolysis process, since tar and char, which are aromatic bituminous substances, are produced simultaneously, it is possible to impregnate char with aromatic bituminous substances in this process.

Therefore, it is possible to impregnate the char obtained by rapid coal pyrolysis with tar, which is an aromatic compound, in the rapid coal pyrolysis process. It has the potential to be used as a blending raw material for industrial coke.

However, as disclosed in JP-A-1-113491, for example, char is collected at 250°C, so there is no tar attached to it, and it cannot be used as a raw material for blast furnace coke in its current state. In addition, a mixing process is required to mix tar and use it as a raw material for blending coke for blast furnaces, resulting in high costs.

The problem to be solved by the present invention is to condense tar, which is an aromatic bituminous substance, in a char pot and mix the tar with the char in order to increase the added value of char obtained by rapid coal pyrolysis. The purpose is to improve adhesion and make it possible to use it as a raw material for blending coke for blast furnaces.

The present invention is based on the above i! l! In order to solve the problem, a method for producing coal rapid pyrolysis char is provided.

[Means for Solving the Problems] When producing char by a coal rapid pyrolysis process, the present invention indirectly cools the temperature inside the char pot to 200°C or less with a liquid to cause tar to adhere to and condense on the char. This is a method for producing coal rapid pyrolysis char characterized by the following.

[Function] The function of the present invention will be explained with reference to the drawings. FIG. 2 is a schematic diagram of the coal rapid pyrolysis process used in the present invention. In FIG. 2, coal is charged into a pyrolysis reactor 1 by hot gas from a circulating gas heater 5. In the thermal decomposition reactor 1, gas components, tar components, and char are produced. At this time, the gas component and the tar component are in a gaseous state, and the char is in a solid state. These products are
Since it is introduced into the charpot 3 in a hot state of 250° C. after being cooled by the heat recovery device 2, the gas and tar are in a gaseous state and the char is in a solid state at this time as well. Therefore, within the char pot, separation of gas components and tar components in a gaseous state and char, which is a solid component, occurs.

The present inventors conducted an experiment using a rapid pyrolysis apparatus to collect char by changing the temperature inside the charpot, and investigated the amount of tar attached to the char. The experimental conditions were a coal supply rate of 2 g/min, a reaction temperature of 700° C. in the thermal decomposition reactor 1, and a residence time of 2 seconds.

Figure 1 shows the relationship between the temperature inside the char pot and the amount of tar attached to the char. The amount of tar attached was expressed as the weight ratio of the attached tar to the total weight of char and tar. Although the amount of tar generated differs depending on the type of coal, 1 wt % or more of tar can be attached to and condensed on the char at a temperature of 200° C. or lower in the charpot. For example, about 10 wt% or more of tar can be attached to and condensed on the char at a temperature of 150° C. in the charpot, and about 24 wt% or more of tar can be attached to and condensed on the char at a temperature of 0° C. in the charpot.

In the present invention, the temperature of the charpot 3 is set to 2 in FIG.
Condensation of the tar on the char was made possible by sufficiently cooling it to below the boiling point of the tar, which is below 00°C. If the temperature of the charpot 3 exceeds 200° C., the temperature is near the boiling point of tar, so the tar may not condense depending on the type of coal.

As a cooling method of the present invention for stably keeping the inside of the charpot below 200°C, as shown in FIG. 2, a water cooling pipe 15 and a liquid nitrogen transport pipe 16 wrapped around the charpot are installed,
A method of cooling using cooling water or liquid nitrogen is adopted. To keep warm, use an insulating material such as Kaol. The water cooling pipe 15 and the liquid nitrogen transport pipe 16 in FIG. 2 were wound alternately in a spiral along the outer peripheral wall of the charpot as shown in FIG. 3. In addition, the temperature can be adjusted using the second
It can be measured by a thermocouple sensor 17 shown in the figure. A total of 27 thermocouple positions 18 were installed evenly in the vertical, horizontal and vertical directions within the charpot as shown by the X marks in Figure 4.
The average value is calculated by a computer built into the temperature control device 6 shown in FIG. 2, and is taken as the temperature in the charpot.

Specifically, the coal is put into the pyrolysis reactor 1 after cooling water is flowed. When the temperature control device 6 is set to an appropriate temperature for the purpose, when the temperature measured by the thermocouple sensor 17 exceeds the set temperature, the temperature control device 6 closes the automatic valve 13 and automatically stops the cooling water. However, when the temperature measured by the thermocouple sensor 17 falls below the set temperature, the automatic valve 13 is opened by the temperature control device 6 and the cooling water flows out. Cooling water is in cooling tower 8
It is not necessary to recycle it by passing it through the pump 11 or by letting it flow out from the manual valve 14.

If it is desired to further lower the temperature to increase the amount of tar condensed, liquid nitrogen may be sent from the liquid nitrogen tank 7 to the charpot via the liquid nitrogen transport pipe 16 for cooling, as shown in FIG. At this time, the cooling water is automatically stopped by the temperature control device 6. When liquid nitrogen is used, the temperature inside the charpot is kept below 50°C, and in this case, the temperature control device 6 opens and closes the automatic valve 12 to stop or flow out the liquid nitrogen depending on the set temperature. It is designed to maintain the temperature. Finally, the liquid nitrogen is converted into pure nitrogen by the evaporator 9 and recovered into the tank 10 as safety nitrogen for preventing oxidation of coal.

The tar-attached char thus obtained is recovered from the charpot after the thermal decomposition is completed.

As described above, before the charpot, the tar components exist in a vapor state as char, and are instantaneously cooled and condensed within the charpot. Therefore, the proportion of tar attached to the char is 1wt% based on the total weight of the char and the tar.
If the ratio of tar attached to the char is less than 1 wt% based on the total weight of the char and the tar, the tar will not be mixed in the entire char, and the coke for blast furnace will not be mixed. A sufficient effect will not be achieved unless tar is further mixed as a blended raw material.

The tar-attached char obtained by the present invention has tar sufficiently mixed in the char and has very good affinity with coal, and even if the coal is non-caking coal, By blending tar-adhered char, it can be used satisfactorily as coke for blast furnaces.

[Example/Example 1] The charpot 3 shown in Fig. 2 was heated using a water-cooling method so that the proportion of tar adhering to and condensing on the char was 15 wt% or more based on the total weight of the char and the tar. The temperature inside was set at 100°C±5°C. The coal used was non-caking coal, the coal supply rate was about 2 g/min, the rapid pyrolysis temperature was 700° C., and the residence time was within 5 seconds for 3 hours.

During operation, the temperature inside the charpot remained stable at 100°C ± 5°C, and tar-adhered char was recovered.

Table 1 shows the results of three experiments conducted under the same conditions and the amount of tar attached to the char extracted by quinoline.

Table 1: Amount of tar attached to char Coal feeding rate was about 2 g/min, rapid pyrolysis temperature was 700° C., residence time was within 5 seconds, and the process was continued for 3 hours.

During operation, the temperature inside the charpot was stable at 0°C±5°C, and tar-adhered char was recovered.

Table 2 shows the results of three experiments conducted under the same conditions and the amount of tar attached to the char extracted by quinoline.

Table 2 Amount of tar attached to char As shown in Table 1, the ratio of tar attached to and condensed on char by the method of the present invention is stably obtained at 15v+t% or more based on the total weight of the char and the tar. Ta.

Example 2 A charpot 3 shown in FIG. 2 was cooled with liquid nitrogen, and the temperature inside the charpot was adjusted so that the proportion of tar that adhered to and condensed on the char was 25 wt% or more based on the total weight of the char and the tar. was set at 0°C±5°C. As shown in Table 2, the coal used was non-caking coal, and as shown in Table 2, by the method of the present invention, the ratio of cour adhering to and condensing on the char was stably obtained at 25 wt% or more based on the total weight of the char and the tar.

Example 3 The charpot 3 shown in FIG. 2 was water-cooled, and the temperature inside the charpot was set to an upper limit of 190°C and a lower limit of 170°C. The temperature measured by the thermocouple 17 shown in Figure 2 is 190
When the temperature exceeds 170°C, the temperature control device 6 closes the automatic valve 13 and automatically stops the cooling water, and when the temperature measured by the thermocouple 17 falls below 170°C, the temperature control device 6 opens the automatic valve 13 to stop cooling. The temperature was controlled to allow water to flow out. The coal used was non-caking coal, the coal supply rate was about 2 g/min, the rapid pyrolysis temperature was 700° C., and the residence time was within 5 seconds for 3 hours.

Table 3 shows the results of three experiments conducted under the same conditions and the amount of tar attached to the char extracted by quinoline.

Table 3 Amount of tar attached to char As shown in Table 3, the ratio of tar attached to and condensed on char by the method of the present invention was stable at 4 to 5 wt% based on the total weight of the char and the tar. .

[Effects of the Invention] According to the present invention, when producing char by a coal rapid pyrolysis process, tar can be attached to and condensed on the char by cooling the temperature inside the char pot to 200° C. or less.

Furthermore, even when the resulting tar-adhered char is blended with coal, a good coke strength equivalent to or higher than that of coal alone can be obtained. Therefore, the coal rapid pyrolysis char obtained by the present invention has an excellent effect that it can be sufficiently used as a raw material for blending blast furnace coke.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between char pot temperature and tar adhesion amount, Figure 2 is a schematic diagram of the process flow when the char recovery method of the present invention is used for rapid coal pyrolysis, and Figure 3 is a diagram showing the relationship between the char pot temperature and the amount of tar attached. FIG. 4, a side view of the pot cooling device, is a three-dimensional schematic diagram showing an example of the position where thermocouples are installed in the charpot in the present invention. 1... Pyrolysis reactor 3... Charpot 5... Circulating gas heater 7... Liquid nitrogen tank 9... Evaporator 11... Pump 13... Automatic valve 15... Water cooling pipe 17...Thermocouple sensor 2...Sensible heat recovery device 4...Talbot 6...Temperature control device 8...Cooling tower 10...Nitrogen tank 12...Automatic valve 14...・Manual valve 16...Liquid nitrogen transport pipe 18...Position of thermocouple and 4 others Figure 18:Position of thermocouple

Claims (1)

[Claims] 1. Coal characterized in that when producing char by a coal rapid pyrolysis process, the temperature in the char pot is indirectly cooled with a liquid to below 200°C to cause tar to adhere to and condense on the char. Method for producing rapid pyrolysis char.