JPS6284178A - Production of coke - Google Patents

Abstract

PURPOSE:To obtain high-strength coke suitable for large-sized blast furnaces, by feeding properly molded coal suitable for difference in clearance produced in the length direction of a furnace of a coke oven, selected depending upon the difference in clearance from plural kinds of molded cokes having different coking actions and carbonizing the coke having qualities and properties. CONSTITUTION:In feeding molded coal 2 to a coking chamber of a coke oven and coking it in the order of carbonization, softening, melting, semicoke and coke, since the molded coal 2 is expanded in clearance 3 between the molded coal 2 and a heated wall 1 during melting process, difference in clearance occurs in the length direction of the furnace. Therefore, molded coal having qualities and properties to show expansion suitable for difference between clearance 3 of a machine side 4 and a clearance 3' of a coke side 5, selected from plural molded cokes having different coking actions, is properly fed to the coking chamber and carbonized, to give the aimed coke.

Description

Detailed Description of the Invention (Field of Industrial Application) The method for producing coke of the present invention is applicable to coke for high strength metallurgy used in large blast furnaces, coke for producing chemically reactive gases such as water gas, coke for smelting reduction, etc. This is a proposal regarding coke production technology for use in new refining coke, etc.

(Prior Art) Normally, coke for steelmaking is used that has good strength and other properties, but such coke has become increasingly expensive as the price of high-quality coking coal has increased in recent years.

In order to reduce costs, it is necessary to use a large amount of inexpensive, slightly caking coal. For example, when a large amount of slightly caking coal is used in the conventional top charging method, the caking property of the coal blend decreases, and the crushing strength DI"°, which indicates the degree of crushing of cracks in coke particles, There was a drawback that the abrasion strength H400, which indicates particle abrasion, and especially Tl400, was significantly reduced.

Block-shaped coal (hereinafter referred to as "briquette coal") manufactured by the stamping method or continuous molding method (Special Publication No. 12710/1983) is a conventional technology that allows the use of large amounts of slightly caking coal.
There is a method (block charging method) in which coke is manufactured by carbonizing coke in a room furnace. In the case of this technology, since a coal block with a high bulk density is carbonized, thermal conductivity is improved and coke productivity is improved by about 15%. When this method is applied to a room-furnace coke oven operating with -i top charging, it can reduce coking coal cost and increase coke production, resulting in a reduction in coke cost and a shortage of coke when an old furnace is abolished. It is effective in replenishing the amount.

FIG. 2 shows a conceptual diagram of a state in which the above-mentioned briquette coal is charged into a chamber furnace. It is usually necessary to design a proper clearance between the coal briquettes 2 and the heating wall 1.1'. However, when trying to carbonize by charging briquette coal into a coke oven (indoor furnace) that is already operating using the top charging method,
In the case of the chamber furnace, the taper of the coking chamber is made larger as a countermeasure against coke jamming, so the clearance of coke side 5 (hereinafter referred to as rcsJ) is larger than that of machine side 4 (hereinafter referred to as rMsJ). In particular, the taper of the indoor furnace for the top charging method is around 601 m (approximately 20 m for block charging), so the clearance increases as you go from old to C3. Because pressure cannot be obtained, bubbles form on the surface of the coke head in C3! fJi texture is observed. There was a drawback that the strength of the coke (DI30 and Tl400) was reduced due to the presence of this cellular structure.

(Problems to be Solved by the Invention) If coke having the above-mentioned foamed II weave is used in a blast furnace, it will be pulverized in the blast furnace, causing various troubles and deteriorating the furnace condition. In addition, when removing the cellular structure in the process before charging the coke into the blast furnace, removal equipment is required, resulting in an increase in coke production costs.

Next, as the unsuitable clearance increases, the amount of bubble-like structure increases. For example, as shown in Fig. 3, the clearance 3 of the machine side 4 is set to 15
When designing with fins, the amount of bubble-like tissue does not increase much at a position where clearance 3 is 25 to 30 fins, but the amount of bubble-like structure increases rapidly when the clearance is between 3 and 55 m2. For this reason, when briquette coal is carbonized in a coke oven that employs the top charging method, the amount of cellular structure increases on the coke side 5 due to the influence of the large taper of the carbonization chamber.

In order to avoid pulverization in the blast furnace, it is possible to pre-process and remove the cellular structure by applying an external force to it, but this will reduce the lump coke yield, so if the amount of cellular Mi fabric increases, There is a problem that the cost of producing lump coke increases.

In short, the present invention solves the above-mentioned problems that occur when carbonizing coal briquettes in a chamber furnace, that is, as can be seen from FIG. The purpose of this study is to develop an effective method to suppress the growth of bubble-like structures that form on the surface of the coke head at the location of the coke head.

(Means for Solving the Problems) To achieve the above-mentioned object, the present invention has a coking effect in accordance with the difference in clearance that occurs in the oven length direction when briquette coal is charged into the carbonization chamber of a coke oven and carbonized. A method for manufacturing coke, which is characterized by charging briquette coal in a suitable place and carbonizing it, which has selected quality characteristics suitable for the difference in clearance from among a plurality of types of coal with different clearances, is adopted as a preferred means for realizing the coke production method. .

The idea of the present invention is to make the quality and properties of briquette coal correspond to changes in the clearance, since differences in the clearance based on the taper of the carbonization chamber cause differences in the growth of the cellular structure.

For this purpose, as shown in Fig. 1, the briquette is divided into multiple parts (2A, -, -, -2N) in the furnace length direction, and each part is given different properties that affect expansion, pressure, and contraction. However, the growth of the cellular Mi weave is suppressed by using briquettes whose quality properties are selected to suit each position according to the so-called clearance difference.

(Function) When briquette coal is carbonized, it is softened, melted, semi-coked, and coked in this order. The melting area is said to be around 20 fins, and during the melting process it expands and produces a pressing effect. That is, although a clearance is provided between it and the heating wall 1, it expands freely until it reaches the heating wall. When it hits the heating wall, pressure is generated, so the pressure must be kept below the strength of the heating wall.

The above expansion is caused by the melting of active components in the coal, and in some cases high coke strength can be maintained by expansion, and in other cases, a gas film is simply formed to weaken the coke strength. The so-called latter case is a case in which a bubble-like structure has developed. This is the small clearance 3 on the machine side 4.
When quality characteristics are set to be suitable for the coke side 5, a large amount of gas film is formed without expansion suitable for the clearance 3', and a bubble-like structure develops. The present invention aims to achieve
This method suppresses the development of cellular m-weave to ensure high coke strength.

Generally, as shown in Table 1, coal has different expansion, pressing, and contraction effects depending on its type. The parameters that indicate expansion are the total expansion rate of the diradometer, the expansion rate, and CSN (
JISM8801), Gieseler plastometer fluidity, various caking parameters, and active ingredients that correlate with expansion.

The above pressure is high for strong caking (charcoal) with low volatile content (JISM8812) and low for weak caking coal.

For example, the shrinkage parameter is volatile content (JISM
(8812). The lower the volatile content, the lower the shrinkage. The expansion representative of the properties of briquette coal;
] Pressure and contraction can be adjusted by the combination of coals.

- For example, the peak-down coal shown in Table 1 has a high total expansion coefficient as measured by a diradometer and shows expansion, but it belongs to the category of strongly caking coal and can obtain high coke strength. Novalmar coal is a highly caking coal, but its expansion is smaller than that of peak-down coal. Oolongdilly coal ′ belongs to the class of highly caking coals, but it has the property of not expanding very much. Among weakly caking coals, Newsol coal exhibits higher expansion than Oolongdilly coal, but its coke strength is low.Wittbank coal, which is a slightly caking coal, does not expand at all and only slightly cakes, resulting in coke formation. Therefore, to give an example of how to think about mixing, on the machine side where the clear lance is small, mix coal, etc., which suppresses expansion and contracts, in large amounts.
Furthermore, by blending expanding coal or the like on the coke side with a large clearance D, it is possible to effectively produce coke with less cellular structure and high strength.

The above-mentioned coal may be a single charcoal or a blended charcoal obtained by mixing two types of charcoal.

In addition to these coals, a binder, coke powder, char, and other carbon materials may be mixed and used.

The quality characteristics of briquette coal that meets the clearance are that when briquette coal turns into coke, it exerts pressure on the heating wall and can achieve high coke strength without damaging the heating wall, while the coke shrinks after carbonization. This expresses the quality characteristics that can be easily extruded from a rice oven. The governing factors are expansion, pressure and contraction.

In particular, expansion and pressing are related to the viscosity of the solution when the coal is melted, the strength of the gas film, the thickness and strength of the expansion layer, and the dispersion state of the ulna, coal inert components, and the blended carbonaceous materials are also affected. do.

The briquettes shown in Fig. 1, especially the continuously connected briquettes, are made to have appropriate quality properties using a method previously developed by the present inventor (Japanese Patent Publication No. 12710/1983). can produce briquette charcoal.

In other words, by leaving the compressed and molded coal that has already been compressed and molded at the outlet of the mold to be charged into the block, the subsequent material obtained by compression molding the newly charged coking coal is left behind. A method of continuously producing compression molded coal of a predetermined size by repeating the operation of combining the following molded coal to form molded coal with a bulk density of 1.0 wet tons/ff13 or more and sequentially extruding it. by.

(Example) Fuse Gojo The blended coal (Table 2) was placed in a mold and molded using a vertical press.

Molded coal dimensions are 1oooma (length') x 670 m
m (height). The width is 350 am if the clearance (one side) is 25 fins, and 316 am if the clearance (one side) is 420 fins.

The coal briquettes were charged into a 250 kg test furnace with a furnace width of 400 mm and carbonized at a furnace temperature of 1200°C. The results are shown in Table 3.

Table 3 This JIS K2151 blending case A is 5% fine coke and 21.4% slightly caking coal.
%, and when the total expansion coefficient was increased to make coke without considering the influence of pressure on the heating wall, the crushing strength DI became extremely high. Blend case B is a case in which a large amount of slightly caking coal that does not exhibit pressure is blended in order to reduce the influence of pressure on the heating wall. When the clearance was as small as 25 fins, Dr''- exceeded the coke strength standard value (DI ・92.0) in a 250 kg test furnace and satisfied coke strength 3. However, when the clearance was as thick as 42 fins, , is low compared to the coke strength standard value mentioned above, and coke cannot be used in blending case B.In this regard, if blending case A, which has a high total expansion coefficient, is made into coke, the clearance will be 42mm. The strength of the first bath was sufficiently satisfactory.

Blend case C is a base piece in which fine coke is not blended. Fine coke is blended to increase the coke particle size, but if a slightly smaller coke particle size is acceptable, blending case C is DI even if the clearance is 42 dragons.
has become higher.

Normally, when briquette coal is carbonized in an existing coke oven that uses the "top charging method," the mixture is designed based on the machine side. In this case, the amount of slightly caking coal used in the above blending case A will be reduced, while in blending case B, a large amount of slightly caking coal will be blended, but the coke side will produce coke that satisfies the coke strength standards. Can not.

In this regard, according to the present invention, while mixing case B is based on the machine side, mixing case A is used on the coke side.

C can be used, and the required high coke strength can be maintained by using a large amount of inexpensive slightly caking coal.

A horizontal molding machine (Tokuko Sho 59-12710
The compression molded coal was extruded from the mold to the outside by molding with a surface pressure of 60 kg/cm. The blending ratios are shown in Table 6.

Table 4 Table 5 *Diradometer compression molded coal is (358 x 2300 x 1000)
Tsuru, T, W9%, bulk density 1.13 wet tons/l113.

Three such briquettes are stacked to a height of 3000mm,
It was charged into an existing coke oven with a length of 15 ffl and a height of 6.5 m and carbonized at 1200°C. The width of the furnace is 38 on the machine side.
It has 8 fins and the coke side is 452 mm. This coke oven operates using the top charging method, so the oven taper is large.

Table 6 Table 7 In this JIS K2151 machine side clearance 15 Tsuru, high coke strength DI is achieved by preparing it to blending case F and carbonizing it.
was gotten. The shrinkage of coke observed before extrusion was also in a normal state, but in blending case E, the shrinkage of coke was slightly less.

When blending case F was carbonized using a coke side clearance of 47 Tsuru, the DI was low. For this reason, if the blending ratio of slightly caking coal B, which does not show expansion, is reduced, carbonization results in D
I improved and satisfied the coke strength standard for blast furnaces.

In combination case G, where the slightly coking coal content was further reduced, the total expansion rate increased and improved over the old case. Blend case H, which contains only standard coal without blending either slightly caking coal or fine coke, can be applied to clearance 47 Dragon, and Of exceeds the coke strength standard for blast furnaces.

Fine coke particles affect coke strength, so it is more effective to use fine coke particles as much as possible. The coke in blending case H, in which fine coke was not blended, was finely granulated.

From these results, it is clear that in existing coke ovens that use the top charging method, briquettes with the quality and properties of blending case F can be produced on the machine side with a small clearance, and blending case D on the coke side with a large clearance. By carbonizing the coal, we were able to meet the coke strength standards for blast furnaces and use a large amount of inexpensive, slightly coking coal.

(Effects of the Invention) As described above, according to the present invention, it is possible to produce metallurgical coke and the like with sufficiently high strength even when briquette coal is carbonized in an existing coke oven. Moreover, since a large amount of inexpensive non-slightly caking coal can be used, the cost of raw materials can be reduced and the unit price of coke can be reduced. Furthermore, the present invention has the effect of improving productivity by about 15%.

[Brief explanation of drawings]

Figure 1 is a route map of a coke oven carbonization chamber showing one embodiment of the present invention; Figure 2 is a route map of a coke oven carbonization chamber in a state of implementation according to a conventional method; Figure 3 is a diagram showing a coke oven heating wall and An explanatory diagram showing the relationship between coke and FIG. 4 is a graph showing the relationship between clearance and bubble structure. 1... Heating wall 2... Molded coal 3... Clearance 4... Machine side 5... Coke side 6... Coke 7... Cellular structure

Claims (1)

[Claims] 1. When charging briquette coal into the carbonization chamber of a coke oven and carbonizing it, select quality properties that match the difference in clearance from among multiple types with different coking effects, depending on the difference in clearance that occurs in the oven length direction. A method for producing coke, characterized by charging selected briquette coal at a suitable location and carbonizing it.