JP2552772B2 - Manufacturing method of molding coke for metallurgy - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a metallurgical process for forming and molding carbonized coal obtained by kneading and molding coal and a binder in a vertical shaft furnace with a high-temperature heating medium gas to carry out carbonization to form a coke for metallurgy. Related to the method of manufacturing molded coke,
The present invention relates to a method for greatly improving the thermoeconomic efficiency in the carbonization process.

[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 is generally used. However, when using the method using this chamber-type coke oven, there is concern about environmental pollution due to leakage of by-products generated during coal carbonization to the outside of the system, and productivity is low because it is a batch-type operation mode, and There is a problem that a large amount of caking coal is required as a raw material and it is not necessarily advantageous from the viewpoint of securing the raw material for a long time. In order to solve such a problem in the method using a chamber furnace type coke oven, for example, Japanese Patent Publication No. Sho 54-17322 discloses a method for directly forming a coke for metallurgy by heating a forming coal in a vertical shaft furnace with a heating medium gas. A method of manufacturing is disclosed.

This coke production process can be a completely closed system, and since it is a continuous operation mode, there is no concern about environmental pollution, and there is an advantage of high productivity. In addition, since coal is kneaded and molded with a binder prior to carbonization to form coal, it is possible to use a large amount of non-slightly caking coal, which is advantageous in terms of securing raw materials. Hold.

In the coke production process by the chamber furnace type coke oven, the heat of the obtained high temperature coke (about 1000 ° C.) is discharged to the outside and the heat conducted through the thick heating wall (about 100 mm) made of silica brick. There was a problem that the thermal efficiency was low due to the coal being indirectly heated by. Despite the fact that no energy is required for the conversion (reaction) of coal into coke, it is usually 550 to 600 Mcal per ton of coal subjected to carbonization.
Needed energy. FIG. 1 shows a typical heat balance in a coke manufacturing process using a chamber furnace coke oven.

On the other hand, the carbonization of the formed coal by the method of directly producing the formed coke for metallurgy by directly heating the formed coal with the heat medium gas in the vertical shaft furnace is carried out by cooling the formed coke in the lower part of the vertical shaft furnace. Since the sensible heat of the coke is recovered and the forming coal is directly heated by the heating medium gas, the thermal efficiency is expected to be extremely high.

Surprisingly, when the molding coke was manufactured by the process of directly heating the molding coal in the vertical shaft furnace with the heating medium gas to manufacture the molding coke for metallurgy, the fuel consumption was Slight reduction (up to 500 Mcal / t / charcoal) compared to the chamber furnace coke manufacturing process
It turned out to be contrary to expectations. Therefore, in order to make the process of producing molded coke for metallurgy by directly heating the molded coal in the vertical shaft furnace with the heat transfer gas, it is necessary to greatly reduce the fuel consumption. Is.

[0007] The above-mentioned report on the heat consumption in the process of directly heating the forming coal in the vertical shaft furnace with the heating medium gas to produce the forming coke for metallurgy is described in the United States Federation of Mining and Manufacturing (AIME) 1986 Iron. -Ma
Lecture at "King Conference""Dev
element of Formed CokePr
process ".

FIG. 3 shows an example of heat balance in the conventional operating method in the process of manufacturing the molded coke by the vertical shaft furnace.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides a method capable of greatly reducing the fuel consumption in the process of producing molded coke for metallurgy by directly heating the molded coal with a heat transfer gas in a vertical shaft furnace. The purpose is to provide.

[0010]

Means for Solving the Problems The feature of the present invention resides in that in a method for directly heating a forming coal in a vertical shaft furnace with a heating medium gas to produce a forming coke for metallurgy, The injection temperature into the vertical shaft furnace is 7
A method for producing a molding coke for metallurgy, characterized in that the temperature of the gas discharged from the furnace top is set to 50 to 850 ° C. and the carbonization of the forming coal is advanced at 180 to 250 ° C.

The present invention will be described in detail below. An example of a vertical shaft furnace used in carrying out the present invention,
As shown in FIG. In FIG. 2, 1 is briquette.
Charging device, 2 is a vertical shaft furnace upper distillation chamber, 3 is a vertical shaft furnace lower cooling chamber, 4 is a molding coke discharge port, 5 is a heat medium gas blowing tuyere, 6 is a furnace top gas extraction duct,
Reference numeral 7 is a gas cooler, 8 is a heating medium gas heater, 9 is a cooling gas blowing tuyere, and 10 is a cooling gas extracting duct.

[0012] The inventors of the present invention have conducted experiments in a small vertical shaft furnace for the purpose of improving the thermo-economic efficiency in the forming coke manufacturing process by the vertical shaft furnace and the results of the experiments in the vertical shaft furnace. A thermal model was created. The apparent specific heat for each temperature of the forming coal including the carbonization reaction heat was obtained by an experiment in a small-scale vertical shaft furnace for experimental use, and the results were used in the vertical shaft furnace including the reaction of the forming coal and the heat transfer gas. A heat transfer model was created, and the conditions under which carbonized carbon could be carbonized in the vertical shaft furnace by varying the flow rate and temperature of the heat transfer gas blown into the vertical shaft furnace and the temperature of gas extraction from the furnace top. did.

Table 1 shows the flow rate and temperature of the heating medium gas blown into the vertical shaft furnace capable of dry distillation of the forming charcoal in the vertical shaft furnace, and the temperature condition for extracting gas from the furnace top, and the heat consumption in that case. The calculation result of the amount is shown. From this, the heat consumption in the forming coke manufacturing process by the vertical shaft furnace was formulated by multiple regression analysis, and the following equation was obtained.

[0014]

[Equation 1]

Here, Q: heat consumption [Mcal / t / molding charcoal] T _gas : heat medium gas blowing temperature [° C.] T _top : heat medium gas withdrawal temperature [° C.]

[0016]

[Table 1]

FIG. 4 shows the heat consumption amount during dry distillation of the shaped coal finally obtained by the inventors by the vertical shaft furnace. It was found that the conventional heating conditions indicated by circles in FIG. 4 consume a large amount of heat. In order to reduce the heat consumption in the carbonization process of forming coal, the temperature of the heating medium gas blown into the vertical shaft furnace should be 750 ° C or higher, preferably 800 ° C.
The present inventors have found that the heat consumption in the carbonization process of forming coal can be significantly reduced by lowering the temperature of the heating medium gas extracted from the furnace top.

Next, the inventors determined the temperature of the heat transfer medium gas blown into the vertical shaft furnace and the limit for lowering the temperature of the heat transfer gas discharged from the furnace top by the method described later. As for the upper limit of the blowing temperature of the heating medium gas, when the formed coal is carbonized at an extremely high temperature rising rate, the formed coal may be swollen in the heating process or cracked in the high temperature shrinkage region (700 to 750 ° C). In order to clarify the upper limit of the temperature at which the heating medium gas is blown, the inventors have variously changed the rate of temperature rise in the central portion of the molded coal and observed the cracking condition of the molded coke as a product. The results are shown in Table 2. The cracking index of the molded coke which is a product in Table 2 is an index showing how many pieces of the molded coke of one molded coal became the product molded coke. According to the knowledge of the inventors, the blowing temperature of the heating medium gas is 900 ° C.
If it is raised up to, the cracking of the briquette will increase significantly.

[0019]

[Table 2]

Contrary to expectations, cracking of the briquette was also observed when the temperature at which the heating medium gas was blown was too low (up to 600 ° C). It is considered that this is a crack due to the fact that the coking of coal does not proceed sufficiently and the strength of the coke substrate is low because the formed coal was carbonized by the low temperature heating medium gas. From these, it was clarified that the heating conditions in the carbonization of the shaped coal were limited.

In this way, the inventors set the blowing temperature of the heating medium gas to 750 to 850 ° C. as an appropriate dry distillation condition in which the heat consumption is small in the dry distillation process of the shaped coal.

Next, as for the temperature of the heat medium gas extracted from the furnace top of the vertical shaft furnace, the lower the heat consumption required for carbonization, the better, as shown in FIG. However, lowering the atmospheric temperature at the furnace top causes clogging of the piping system due to condensation of tar in the by-product gas generated from coal.
According to the knowledge of the inventors, in order to prevent clogging of the piping system due to condensation of tar in the by-product gas, the ambient temperature at the furnace top has a lower limit of 180 ° C. On the other hand, although the upper limit of the atmospheric temperature at the furnace top is not particularly specified in terms of the operation of the carbonization process of the shaped coal, it is limited to 250 ° C. from the viewpoint of the thermal economy of the carbonization process of the shaped coal.

[0023]

[Example] Using a carbonization device for forming charcoal in a vertical shaft furnace shown in FIG.
The temperature of the heating medium gas extracted from the furnace top: 200 ° C,
Operated.

In order to satisfy the above conditions, it is necessary to blow the heat medium gas at 1200 Nm ³ / t · forming coal, and the heat amount required for the carbonization of the forming coal at this time is 180 Mca.
It was 1 / t / formed charcoal. Heat consumption (500Mcal /
FIG. 5 shows a comparison of the heat consumption amount in the present invention with t.

[0025]

EFFECTS OF THE INVENTION According to the present invention, the heat consumption amount in the carbonization process of the shaped coal in the vertical shaft furnace can be reduced to 40% or less of the value by the conventional method, which is a great industrial effect.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of heat balance in a conventional chamber furnace coke manufacturing process.

FIG. 2 is a diagram showing an example of a molding coke manufacturing apparatus using a vertical shaft furnace when the present invention is carried out.

FIG. 3 is a diagram showing an example of heat balance in a process for producing a molded coke by a vertical shaft furnace by a conventional method.

FIG. 4 is a diagram showing the relationship between operating conditions and heat consumption in the process of forming coke in a vertical shaft furnace.

FIG. 5 is a diagram showing a comparison of heat consumption in a process for producing molded coke by a vertical shaft furnace and heat consumption in a process for producing molded coke by a vertical shaft furnace according to the present invention by a conventional method.

[Explanation of symbols]

1 ... Forming charcoal inserting device 2 ... Vertical shaft furnace upper carbonization chamber 3 ... Vertical shaft furnace lower cooling chamber 4 ... Molding coke discharge port 5 ... Heat medium gas blowing tuyere 6 ... Furnace top gas extraction duct 7 ... Gas cooler 8 ... Heat medium gas heater 9 ... Cooling gas blowing tuyere 10 ... Cooling gas extracting duct

Claims (1)

(57) [Claims] 1. A method for directly heating a forming coal in a vertical shaft furnace with a heating medium gas to produce a molding coke for metallurgy, wherein the temperature of blowing the heating medium gas into the vertical shaft furnace is 750 to 850. C. and the temperature of the gas discharged from the furnace top is 180 to 250.degree. C. to allow the dry distillation of the forming coal to proceed, thereby producing a forming coke for metallurgy.