JPS58127780A - Preparation of formed coke - Google Patents

Abstract

PURPOSE:To obtain formed coke with improved thermal efficiency and capable of substantially simplifying carbonization equipment, by carbonizing formed coal in contact with reduced iron or iron oxides heated to a particular temp. and using the resulting formed coke as a raw material for a blast furnace. CONSTITUTION:Carbonization of formed coal is effected by bringing it into contact with reduced iron or iron oxides, massive or formed in lumps, under laminated or mixed conditions heated to a temp of from 600 deg.C to the m.p. thereof. The resulting formed coke is used as a raw material for a blast furnace with or without separation from reduced iron or iron oxides. The reason why the heating temp. of said solid heating medium is 600 deg.C or higher is as follows: Generally, the temp. at which the strength of coke is developed as a result of carbonization of formed coal is assumed to be 500 deg.C or higher at which pyrolysis and heat polymn. of molten components or binders in coal are nearly completed. When the temp. of the heating medium is low, the longer carbonization period and reduced strength of formed coke result. Therefore the temp. of the heating medium is required to be 600 deg.C or higher.

Description

[Detailed Description of the Invention] The present invention relates to a method for producing molded coke, particularly a method in which the molding method is carbonized into coke by direct heating with a solid heating medium, in response to the remarkable development of the steel industry in recent years. As a result, the consumption of coke, one of the raw materials for steelmaking, has increased enormously. However, not only is there a limit to the supply of coking coal that is essential for producing coke, but it is also difficult to maintain the current quality of coking coal into the future. Therefore, research is underway in countries around the world to produce coke for high-fired coke using non-caking coal or slightly caking coal as the main raw material, which is almost universally present on earth and has abundant resources. Among these studies, the development of molded coke production methods is urgently needed as a promising coke production technology in the future, but the technology to economically produce molded coke on an industrial scale has not yet been established. This is the actual situation.

Various reasons have been proposed for this, but one of the biggest is that the energy cost required for carbonization is greater in the molded coke production method than in the normal coke production method.

In other words, methods for producing molded coke can be roughly divided into two methods: a method in which the molding method is directly heated with a high-temperature inert gas, and a method in which the molding method is directly heated with a solid heating medium. Because the high-temperature inert gas mixes with the gaseous volatile components generated by the carbonization of the molding process, not only does the overall gas calorie decrease, but it also prevents the tar content in the gas from condensing. The disadvantage is that the gas humidity must be made higher than necessary, and the sensible heat generated is disadvantageous in terms of energy. In addition, it has been pointed out that although the latter method of directly heating briquette coal with a solid heating medium eliminates the above drawbacks, the thermal efficiency is poor when reheating and circulating the solid heating medium, and energy costs are not necessarily reduced. I can come out. In addition, here, as a solid heat medium, it is
As shown in No. 7-2125, calcined coal, sand, and even particulate solid heat medium such as coke powder are used. This is thought to be because the molded coke and the heating medium can be easily separated, the heat transfer area between the two is increased, and the carbonization time can be shortened.

The purpose of the present invention is to improve the low thermal efficiency, which is a drawback of known methods, while taking advantage of the advantages of a molded coke manufacturing method using a solid heating medium, and to produce molded coke that enables simplification of carbonization equipment. Our goal is to provide you with a manufacturing method.

By the way, the basic condition for a solid heating medium in conventional solid heating medium molded coke g (v base system) is that it can be used in circulation.For this reason, the solid heating medium has a fraction of the molded coke g It is believed that a solid heat medium in the form of fine particles is desirable because it is easy to heat, reheat, and has a large heat transfer area, and based on this idea, calcined coal, sand, coke powder, etc. have been used. If we change this solid heating medium from one that is intended to be used as a shield ring to one that is not reused, especially one that can be reused as a raw material for melting, the solid heating medium will not only be wasted. , the reheating step and the circulation step of the solid heating medium are omitted, the carbonization equipment can be greatly simplified, and the thermal efficiency is also significantly improved.

The present invention is based on this idea, and the present invention is based on this idea.
carbonizing the briquette coal by bringing it into contact with lumpy or agglomerated reduced iron or iron oxide heated to a temperature of 0'C or more and below the melting temperature in a layered or mixed state;
The gist of the present invention is a method for producing molded coke, characterized in that the molded coke obtained by carbonization is used as a raw material for a blast furnace without being divided with the reduced iron or iron oxide or being separated.

In other words, the molded coke production method of the present invention is basically a method using a solid heating medium, but as a solid heating medium, it can be formed into lumps or agglomerates that are not a problem as a raw material for smelt or mackerel heated in another process. Reduced iron 1l-1: Since iron oxide is used, the solid heat medium is not recycled as a heat medium, and the solid S medium is not wasted. Not only does this prevent an increase in raw material costs, but because the solid heat medium is not used repeatedly as a heat medium, the carbonization equipment can be greatly simplified and its thermal efficiency can be greatly improved.

In addition, in the method of the present invention, the solid heating medium used is one that does not pose a problem as a raw material for blast furnaces, and the coke obtained is also one of the raw materials for smelting and melting, so it cannot be molded as in the conventional method. It is not necessarily necessary to separate the coke from the solid heating medium, and from this point of view as well, it is possible to reduce the number of man-hours.

In the method of the present invention, the solid heating medium is in the form of lumps or agglomerates, but since the thermal conductivity of reduced iron or iron oxide is better than that of calcined coal, sand, and powdered coke, it is Compared to conventional methods using these solid heating media, the carbonization time does not become longer.

Table 1 shows the comparison of the method of the present invention with the conventional molded coke manufacturing method using a solid heating medium.

Below in Table 1, the method of the present invention will be explained in more detail in the following order: shaped coal, solid heating medium, shaped coke, and comparative test.

Molded Charcoal> The molded coal used in the method of the present invention is a normal molded coal, but it is preferable to dry it and/or preheat it to a temperature of 250° C. or lower in advance.

This is because, although the higher the temperature of the solid heating medium (described later), the shorter the carbonization time and contributing to improved productivity, the larger the temperature difference between the briquette coal and the solid heating medium, the more This causes a large temperature difference in the briquettes, which causes many cracks in the briquettes and reduces coke strength. This is because by preheating the coke to a temperature below .degree. C. or by performing both, the occurrence of these cracks can be suppressed and a decrease in coke strength can be prevented.

Solid heating medium> The solid heating medium to be brought into contact with the briquette coal is reduced iron or iron oxide, since the heating medium is reused as a raw material for smelting and burning. It is important that these heating media be in the form of lumps or agglomerates in order to maintain air permeability within the blast furnace.

As such a heating medium, reduced iron obtained by the direct reduced iron manufacturing method, fired pellets or sintered ore, which are generally used as blast furnace charging raw materials, may be used in a state before cooling. By doing so, the sensible heat of these heating mediums is effectively diverted to the carbonization of briquette coal, eliminating the need for a separate process of heating the heating medium, and making it even more advantageous in terms of man-hours and energy costs.

The heating temperature of the solid heating medium is set to 600"C or higher and lower than the melting temperature for the following reasons.

-4, briquette coal is carbonized and develops its strength as coke at temperatures above 500°C, where the molten component or binder in the lime has almost completed its thermal decomposition and thermal polymerization. Therefore, in order to carbonize briquette coal using a solid heating medium, it is necessary to heat the noxious medium to a temperature range of at least 500° C. or higher.

However, when the temperature of the heating medium is low, the carbonization time becomes long and the strength of the molded coke becomes low. For these reasons, the temperature of the heating medium is required to be 600°C or higher.

Note that the fact that the upper limit of the heat medium humidity is set to the melting temperature of the heat medium does not require much explanation.

The solid heating medium and the briquette charcoal may be brought into contact with each other by either mixing or lamination, or any method in between.

Molded coke〉 Molded coke carbonized by contact with the solid heating medium can be separated from the solid heating medium and used as raw material for smelting and brain pressure, but solid heating medium can also be used as raw material for blast furnaces. 1
Therefore, it can be used as a raw material for the first stage of smelting together with the solid heating medium without being separated from the solid heating medium.
The above point is also one of the major features of the method of the present invention.

Comparison Test 1〉 As shown in Figure 1, a batch-type rotary furnace (1) with an inner diameter of 1050 mm and a depth of 600 mm was equipped with an iron oxide bezel with a diameter of 10 to 20 mm.
After charging 100 kq and heating to each temperature shown in Table 2, each pellet was discharged from the rotary furnace (1) and immediately made into a pellet with a raw material composition of 651 ff (length) x 65 w (width) x shoulder x thickness (width) as shown in Table 3. The mixture was mixed with 25 kq of 45 mm mass molded p.sub.25 kq, and carbonized in a heat insulating container. The thermal container is the second one.
As shown in the picture, there are four types of thermocouples (suburban couple for measuring the temperature of the charged material (9), thermocouple Q for measuring temperature at the center of briquettes, thermocouple for measuring side wall heat retention temperature (1). , 1) and the thermocouple α2) for measuring the bottom heat retention temperature and the electric heater α■ can adjust the external heat retention of 4 degrees according to the temperature change of the charge, ensuring the insulation state of the charge. Yo (F, it's something I've devised.

In addition, the 11th yen? In I, (2) is the sample loading lid, (
3) is the measurement/□Im hole, (4) is the burner, (5) is the afterburner chamber, (6) is the dust extraction, (7) is the flue,
(8) represents a mixer.

The strength of the molded coke after each of the above carbonization tests, the maximum carbonization temperature at the center of the molded coke, and the heating time at the maximum carbonization temperature are also listed in Table 2.

For the sake of filial piety, as a solid Sui I, Q, 5 Dragon ~ 3
, Q vz sized grains were heated to 1000° C. and subjected to a similar carbonization test, and are shown in Table 2 as test flat 6.

Table 2 *) To measure the strength of molded coke, three iron oxide pellets were used.
The coke was removed using a square sieve with zero resistance, and the molded coke on the sieve was subjected to strength measurement.

Table 3 As is clear from these test results, it was confirmed that molded coke having good coke strength could be produced in a short time by using the method of the present invention.

In other words, test strips 1 to 5 used iron oxide pellets as the heating medium, and it can be seen that the higher the heating medium temperature is, the stronger the formed coke tends to be, and the carbonization time is shorter. . but.

In test boiling (2), where the heating medium temperature is the lowest (outside the range of the present invention), not only the carbonization time is long, but also the strength of the molded coke is extremely low, and it cannot withstand use in a side-bottom blast furnace. This is thought to be due to insufficient carbonization due to the low maximum carbonization temperature. Therefore, it is determined that a heating medium temperature of 600° C. or higher is required.

In addition, although the temperature is within the range of the present invention, the highest temperature is 12
0(l), the molded coke strength is lower than that of test strip 4, which has a lower heating medium temperature, even though the maximum carbonization temperature is high and the carbonization time is short.This is because
It is believed that if the heating medium temperature is too high, many cracks will form in the molded coke as described above, and it is desirable to make some quality improvements in order to use this as a raw material for blast furnaces.

Furthermore, if we compare the results of Test A6, which is the conventional method, with Test Strip 4, which was conducted under the same conditions using the method of the present invention, there is no significant difference between the two in terms of molded coke strength and carbonization time, and the results show that the results of Test A6, which is the conventional method, are not significantly different between the two in terms of molded coke strength and carbonization time. Are you saying that the inventive method is in no way inferior to the conventional method?The inventive method does not require a reheating process or a circulation process for the heating medium, and has achieved a large simplification of the carbonization equipment and a large improvement in thermal efficiency. When you consider these things, you can understand that its industrial value is extremely large.

Comparative test @2 Heating temperature 1200 obtained using the same method as Comparative test @1
℃ iron oxide beretsu l-101, same as the Japanese school exam 1〉
25 kq of the same briquette charcoal used in Example 1 was dried and/or preheated and mixed as shown in Table 4, and carbonized in a heat-insulating container shown in FIG. These test results are also listed in Table 4.

Table 4 As is clear from Table 4, compared to Test 5 conducted in Comparative Test 1, in Tests 7 to IO, which dry and/or preheat the briquette coal in advance, the carbonization time was reduced. The strength of the molded coke has been greatly improved, and drying and/or preheating of the molded coal is effective in shortening the carbonization time and improving the strength of the molded coke (especially when the heating medium temperature is high). confirmed.

In Test Group 10, in which the molten coal was preheated to 250°C, a slight decrease in strength was observed in the molten coke, which is thought to be due to slight thermal decomposition of the binder in the molten coal.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the rotary furnace used in the comparative test, and FIG. 2 is an explanatory diagram of the heat-insulating container. In the figure, 1: rotary furnace, 4: burner, 9 to 12: thermocouple, 13: electric heater. Applicant: Sumitomo Metal Industries, Ltd. [J - Continued from page 1] Inventor: Michiharu Hadano, 1-3 Nishinagasu Hondori, Amagasaki City, Sumitomo Metal Industries, Ltd., Central Technology Research Laboratory

Claims (1)

[Claims] (1) The molding method is brought into contact with lumpy or agglomerated reduced iron or iron oxide heated to 600 C or above and below the melting temperature in a layered or mixed state to carry out carbonization in the above molding method. A method for producing shaped coke, characterized in that the shaped coke obtained by the carbonization is separated from the reduced iron or iron oxide, or used as a raw material for blast oring and furnaces without separation.