JPS59126703A - Operating method of hot stove - Google Patents

Abstract

PURPOSE:To improve thermal efficiency in a hot stove installation for a blast furnace consisting of three units of hot stoves by overlapping the start of blasting to the another hot stove in the end period of the blasting stage for each hot stove at a prescribed ratio. CONSTITUTION:A hot stove installation for a blast furnace consisting of three units of hot stoves A, B, C is selectively operated according to a cycle consisting of a combustion stage, pressurizing stage and blasting stage, by which hot wind is fed successively to a blast furnace 4. A part of the blasting stage for one other hot stove B is started in overlap at an overlap rate of <=40% of the entire period in each blasting stage at the end period of the blasting stage for the hot stove A. The blasting overlapped from the furnace B to the furnace C and from the furnace C to the furnace A is thereafter repeated in the same way. Since there is no need for maintaining the hot wind at the temp. considerably higher than the assigned temp., thermal efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating a hot air stove, and more specifically,
This invention relates to a method of operating a blast furnace hot blast furnace consisting of three hot blast stoves.

Generally, when three hot blast furnaces are provided for one blast furnace, the blowing system of the hot blast furnace equipment is configured as shown in FIG. That is, the cold air sent from the blower 1 to the hot-air stoves A, B, and C via the blower valves 2a, 2b, and 2c, respectively, is heated in the heat storage chamber of the hot-air furnace, becomes hot air, and is sent to the hot-air valves 3a, 2b, and 3. B+3 Blast furnace 4 via c
Air is blown to In this case, as shown in the schedule in Figure 2, each hot blast furnace is operated in sequence so that one unit is always in the ventilation state and the other two are in the combustion state. The hot air that is blown must always maintain a specified temperature, but in the case of the single air blowing method as described above, the temperature of the hot air heated in the heat storage chamber tends to drop at the final stage of the blowing process. , the temperature of the air blown to the blast furnace may become low at the end of the air blowing process. For this reason, conventionally,
In order to ensure the specified temperature of blast furnace air (for example, 1100°C), excess energy is input in advance to store heat so that the hot air temperature reaches the specified temperature at the end of the air blowing process.
During the first half of the blowing process, excessively high temperatures (e.g. 1300
The conventional method was to obtain hot air at a temperature of 180°C and then blow cold air (approximately 180°C) into it to adjust the temperature to a predetermined temperature. In addition, if the temperature of the air source at the beginning of the air blowing process is 1300°C, the air temperature at the end of the air blowing process (60 minutes later) will be approximately 11
The temperature will be around 50℃. In Figure 1, 5a, 5b
, 5c is a mixed cold air valve for supplying cold air. As described above, in the conventional single air blowing method, excessive energy was input and excessive heating occurred. Since the temperature had to be adjusted using cold air, heat loss was unavoidable, but thermal efficiency was poor.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a hot-air blower that can achieve hot air blowing at a predetermined temperature through the blowing process without having to invest a large amount of excess energy to obtain hot air at a temperature much higher than the predetermined blowing temperature. An object of the present invention is to provide a method of operating a hot blast stove that can reduce fuel consumption.

The present invention is a blast furnace hot blast equipment consisting of three hot blast furnaces, and at the end of the blowing process of each hot blast furnace, the other one
Start by partially overlapping the blowing process of the hot air stove,
It is characterized in that the overlap ratio is set to 40 times or less for the entire period of each air blowing process.

Next, the present invention will be explained based on the drawings.

FIG. 3 shows an example of a ventilation schedule according to the method of the present invention. The air blowing systems of hot air stoves A, B, and C basically have the configuration shown in FIG. Each of the hot blast furnaces A, B, and C is operated in a switching manner according to a cycle consisting of a combustion process, a pressurizing process, and a blowing process, and sequentially blows hot air to the blast furnace. According to the example of FIG. 3, when the hot air stove A enters the blowing process, the hot air stove B shifts from the composting process to the pressurizing process. On the other hand, the hot air stove C moves from the blowing process to the exhausting process and then to the combustion process. Next, when the blowing process of hot air stove A reaches its final stage,
Hot air stove B enters the air blowing process, and blows air that partially overlaps with the air blowing from hot air stove A. When the hot air stove B blows air, the hot air stove C shifts from the combustion state to the pressurized state, and at the end of the air blowing process of the hot air stove B, the hot air stove C also enters the blowing state. In this way, at the end of the blowing process of the hot air stove B, the blowing air from the hot air stove C is partially overlapped. Similarly, when hot air stove C is in the blowing process,
The hot air stove A changes from the combustion state to the pressurized state, and then, at the end of the air blowing process of the hot air stove C, the air blowing starts partially overlapping with the air blowing of the hot air stove C. By repeating the above switching operation, the furnace operating method of the present invention is carried out.

More specifically, in each of the houses A, B, and C, during the combustion process, heat is stored so that the initial hot air temperature is slightly higher than the designated blast furnace air blowing temperature. For example, if the designated blast furnace air temperature is 1100℃,
Heat is stored to a certain extent.

As mentioned above, conventionally, in order to blow air at 1100°C, heat is stored so that the initial hot air temperature is about 1300°C, and the operation is carried out to obtain hot air of about 1150°C at the end of the blowing process. However, according to the present invention, heat storage of, for example, about 1200° C. is performed. Then, when this heat storage temperature decreases at the end of the blasting process and the blasting temperature becomes lower than the specified blast furnace temperature, the blasting process of that hot blast furnace is partially oversubscribed and the blasting of another hot blast furnace is started. , the whole unit blows hot air at a specified temperature.

The amount of air blown by the hot blast furnace, which blows air over and over, is distributed so that the temperature of the hot air blown to the blast furnace as a whole is a specified temperature or slightly higher than the specified temperature. When the hot air temperature is higher than the specified temperature, it is mixed with cold air in a mixing chamber to adjust the temperature.

The overlap ratio in the blowing process of the hot air stove, which blows air partially overlappingly, is selected so that the thermal efficiency of the hot air stove is maximized. At this time, the combustion equipment capacity of B gas and tar, which are the fuel of the hot stove, the maximum amount of B gas and tar that can be combusted per unit time from a pollution standpoint, the maximum exhaust gas temperature,
The silica stone temperature mm etc. are taken into consideration. When the air blowing processes are overlapped, each has an effect depending on the overlap ratio, but generally the overlap is about 40 factors for the entire period of each air blowing process. This is because if the overlap ratio exceeds 40, the hot air stove switching operation becomes frequent, which increases the amount of work and causes an economical problem.

As is clear from the table above, by changing the air blowing process to 5 or 10, the thermal efficiency can be reduced by 0.3.
It can be improved by 0.77% by 7%.

As described above, according to the present invention, there is no need to input large excess energy during combustion to make the initial hot air much higher than the specified temperature, so it is possible to improve thermal efficiency and to adjust the air blowing temperature. It is economically advantageous because the amount of cold air required for blowing can be reduced.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the ventilation system of a hot-blast stove facility consisting of three hot-blast stoves, and Figure 2 is a schematic diagram of the single-blast fan system.
FIG. 3 shows a blower scale according to the present invention. 1...Blower 2 a, + 2 b y 2 c...
Blow valves 3a, 3b, 3c...Hot air valve 4...Blast furnace 5a,
5b, 5c ``Mixed cooling! Valve A, B, C...Hot blast furnace patent applicant Sumitomo Metal Industries, Ltd. One wind - Moe 1 standing L - J Kozuki

Claims (1)

[Claims] (1) In a blast furnace hot-blast equipment consisting of three hot-blast stoves,
At the end of the blowing process of each hot air stove, the blowing process of another hot air stove is started by partially overlapping the blowing process, and the overlap ratio is set to 40 times or less of the entire period of each blowing process. How to operate a furnace.