JPH0665578A - Production of metallurgical formed coke - Google Patents

Abstract

PURPOSE:To decrease the amt. of a recycled heat medium gas to thereby decrease the consumption of a heating fuel and downsize a gas-recycling apparatus by specifying the amt. of heat supplied by the heat medium gas and the temp. of the gas extracted through the top of a shaft in the process for coking a coal briquet by heating it in a shaft furnace. CONSTITUTION:A metallurgical formed coke is produced by coking a coal briquet (delivered through 1) by heating it with a heat medium gas coming through a low-temp. tuyere 5 and a high-temp. tuyere 6 in a shaft furnace (2, 3, 4) under such conditions that 15-25% of the total heat supplied is supplied by the heat medium gas coming through the high-temp. tuyere 6 and that the temp. of the gas (9) extracted through the top of the shaft of the furnace is 140-200 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention produces molded coke for metallurgy by heating two stages of low temperature gas and high temperature gas in a vertical shaft furnace to dry-form carbonized coal which is obtained by kneading coal and a binder. Involved in how to do.

[0002]

2. Description of the Related Art As a method for producing a metallurgical coke from coal, a method using a chamber furnace type coke oven having a coal carbonization chamber and a fuel gas combustion chamber separately is generally adopted.

However, in the above method, it is feared that the environment will be polluted by external leakage of by-products generated during coal carbonization, and since it is a batch operation, the productivity is low and a large amount of coal is used. The disadvantage is that caking coal is required.

However, in recent years, a method for producing a molding coke for metallurgy which solves these problems has attracted attention, and two-stage heating is performed by a low-temperature and high-temperature circulating heat transfer medium gas using a vertical shaft furnace to dry-distill the molding coal. , A method for producing molded coke has been developed (for example, Japanese Patent Publication No. 60-3
8437).

This method can be completely sealed and is a continuous production method. Since coal is pre-briquetteed, a large amount of non-caking coal can be used. Is expected.

For the production of such molded coke, 20
It is recognized that a 0t / D pilot plant was constructed, stable production was possible, and the produced metallurgical coke had strength comparable to that of conventional chamber furnaces.

(Public reports include, for example, American Federation of Mining and Industry (AIME) 1986 ironking.
Lecture at conference "Development"
tof Formed Coke Process ". )

[0008]

However, when adopting this molding coke manufacturing method as an actual production facility, it is necessary to outperform the room furnace in terms of economic efficiency, and the technology developed in the pilot plant is required. Is desired to be further improved.

[0009] Specifically, the coking energy is the same as that of the chamber furnace because the molding charcoal at room temperature is heated to 900 to 1050 ° C in manufacturing the molding coke. But,
There is a problem that the amount of heat taken out by the heating medium gas taken out from the furnace top is large and the power for circulating the heating medium gas is added, so that the total energy consumption increases.

Further, since the coal gas generated during carbonization is circulated and used as the heating medium gas, [collection at the shaft top] →
A complicated process of [cooling] → [gas purification] → [heating] → [blowing from the lower tuyere of the shaft] is required, and this gas circulation equipment occupies the majority of the forming coke manufacturing plant.

That is, in order to improve the economical efficiency of the molding coke manufacturing method, it is most effective to reduce the circulation amount of the heat medium gas.

[0012] The present invention provides a method for reducing the amount of circulation of a heat medium gas when producing a metallurgical molding coke, thereby reducing the amount of fuel used for heating and making the gas circulation equipment compact. provide.

[0013]

The method for producing a forming coke for metallurgy according to the present invention comprises heating a forming coal in a vertical shaft furnace with a heat medium gas blown from a low temperature tuyere and a high temperature tuyere, and coking the coke. In the method of producing a molded coke for metallurgy, the heat supply amount supplied by the heat medium gas blown from the high-temperature tuyere is 15% or more and 25% or less of the total heat supply amount, and is collected and extracted at the top of the shaft. It is characterized in that the temperature of the heat medium gas is set to 140 ° C. or higher and 200 ° C. or lower.

The present invention will be described in detail below along with its operation.

[0015]

FIG. 1 is a schematic view showing an example of a process for producing a molded coke by a vertical shaft furnace to which the present invention is applied. 1
Is a briquette forming charcoal charging device, 2 is a shaft upper carbonization chamber, 3 is a shaft lower cooling chamber, 4 is a molding coke discharge port, 5 is a low temperature heating gas blowing tuyere, 6 is a high temperature heating gas blowing tuyere, 7 Is a cooling gas blowing tuyere, 8 is a temperature rising gas extraction duct, 9 is a furnace top circulating gas extraction duct, 1
Reference numerals 0 and 11 denote a circulating gas cooler, 12 denotes a low temperature blown gas heater, and 13 denotes a high temperature blown gas heater.

FIG. 2 shows an example of the heat balance of the vertical shaft furnace.

In order to produce a molded coke without causing cracks in the molded coal, the rate of temperature rise at the center of the molded coal is 5 ° C / 500 ° C to 650 ° C at which coal changes into semi-coke. It has turned out that it needs to be adjusted to be less than a minute.

According to the heat transfer calculation of the shaft furnace, the inventor
The temperature at which the top gas of the shaft furnace satisfying the above conditions was extracted, the required amount of heat medium gas blown from each tuyere, and the required heating energy amount at that time were calculated.

Table 1 shows an example of the results. As a result, by adjusting the heat quantity of the heat carrier gas blown from the high temperature tuyere to at least 15% to 25%, preferably 19% to 22% of the total heat quantity, without increasing the temperature rising rate of the briquette core. It was found that the temperature of the gas extracted from the furnace top could be lowered. In Table 1, the value in [] indicates the ratio of the heat quantity of the high-temperature tuyere heating medium gas to the total heat quantity.

Further, the furnace top gas temperature is usually set to 2
It was revealed that by lowering the temperature from 70 ° C. to 200 ° C., the heat medium circulation amount was about 80%, and the heating energy usage amount was significantly reduced to 3/4.

This effect is enhanced by further lowering the furnace top gas temperature, but the effect width is gradually reduced.

In order to determine the lower limit of the furnace top gas temperature, the change in the properties of the generated tar with respect to the temperature, which is the most problematic when the furnace top temperature is lowered, was measured.

In order for tar to be handled as a fluid without any problem, its viscosity must be 50 CP (centi-poise) or less. The measurement results are shown in FIG. When the atmospheric temperature is lower than 130 ° C., the viscosity increases to 750 CP or higher, so it was concluded that the furnace top gas temperature is desirably at least 130 ° C. or higher, preferably 140 ° C. or higher.

From the above results, regarding the economical design and operating method of the molding coke manufacturing equipment in which the molding coal is blown in the vertical shaft furnace by injecting the heat medium gas from the two-stage tuyeres of high temperature and low temperature to carry out dry distillation, The heat supply amount supplied by the heat transfer gas blown from the mouth is 15% or more and 25% or less of the total heat supply amount, and the temperature of the heat transfer gas extracted from the top of the shaft is 1
The temperature is set to 40 ° C or higher and 200 ° C or lower.

[0025]

[Table 1]

[0026]

EXAMPLE FIG. 4 shows an example of the heat balance of the vertical shaft furnace when the temperature of the gas discharged from the furnace top is 150 ° C.

Under this temperature condition, the amount of gas blown in is about 2/3, and the amount of heat blown in is about 3/4, as compared with the case where the furnace top temperature is 270 ° C. which is the conventional operating condition shown in FIG. Has become.

In particular, when the amount of heat recovered by cooling the coke in the lower part of the shaft is subtracted, it can be seen that there is a reduction effect of 50% or more in comparison with the amount of fuel used for the heater.

[0029]

Industrial Applicability According to the present invention, the vertical shaft furnace molding coke equipment can be made compact and the energy used can be greatly reduced, and it can be said that the present invention is industrially very significant.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a process of manufacturing a molded coke by a vertical shaft furnace.

FIG. 2 is a diagram showing an example of a heat balance in a molding coke manufacturing process using a vertical shaft furnace in a conventional method.

FIG. 3 is a diagram showing a relationship between an atmospheric gas temperature and a tar viscosity.

FIG. 4 is a diagram showing an example of a heat balance of a process for producing a molded coke by a vertical shaft furnace in the method of the present invention.

[Explanation of symbols]

1 ... Briquette (charcoal) charging device 2 ... Shaft upper carbonization chamber 3 ... Shaft lower cooling chamber 4 ... Molded coke discharge port 5 ... Low temperature heating gas blowing tuyere 6 ... High temperature heating gas blowing tuyere 7 ... Cooling gas blowing feather Port 8 ... Temperature rising gas extraction duct 9 ... Furnace top circulating gas extraction duct 10, 11 ...
Circulating gas cooler 12 ... Low temperature blown gas heater 13 ... High temperature blown gas heater

Claims (1)

[Claims] 1. A method for producing a molded coke for metallurgy by heating the forming coal in a vertical shaft furnace with a heat medium gas blown from the low temperature tuyere and the high temperature tuyere to produce coke for the metallurgy. The heat supply amount supplied by the blown heat transfer gas is 15% or more and 25% or less of the total heat supply, and the temperature of the heat transfer gas extracted from the shaft top is 1
A method for producing a molding coke for metallurgy, which is 40 ° C. or higher and 200 ° C. or lower.