JPS60174482A - Method of heating industrial furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating method for a furnace, and is particularly used for drying and preheating a large-scale industrial furnace having a complicated shape.

In general, after a furnace is constructed or repaired, and before it goes into operation, it is used to remove moisture from the refractory lining, dry it to develop structural strength, absorb thermal expansion of the refractory lining, and perform sintering. Preheating is performed for such purposes, and the temperature is further raised to a predetermined temperature before operation begins. The quality of this drying and preheating work has a great effect on the refractory lining of the furnace body and the furnace shell, and is also related to the lifespan of the furnace body, so this work is one of the important processes before operation. There is.

J- For drying and preheating of the various industrial furnaces mentioned above, use a general radiation burner, use the operating burner of the furnace body for both drying and preheating, or use a non-radiation type high velocity burner to blow high-speed hot air into the furnace. This is done through methods such as internal circulation.

By the way, it is difficult to uniformly heat the drying and preheating of large furnace bodies such as glass melting furnaces and hot blast furnaces for steel manufacturing, which are large in size and have complicated furnace structures among various kinds of two-build furnaces, and it takes a long time to perform the work. In this case, increasing the heating rate will result in damage to the refractory lining and other parts due to localized heating.

For this reason, drying and preheating of these large complex furnaces has traditionally been
This is carried out using a high velocity burner as shown in Figures (a) and (b) and by a special heating method.

That is, 1 in the figure is a main body cylinder, and an inner cylinder part 2 having a slit on the side surface is inserted into this main body cylinder l from one end side, and is attached with bolts and nuts at a flange part 3.3 to form the burner main body. It consists of The inside of the inner cylinder part 2 is a combustion chamber 4, and a fuel nozzle 5 is inserted into the combustion chamber 4 from one end side of the inner cylinder part 2. Further, a combustion/dilution air supply hole 6 is provided at a position corresponding to the side surface of the combustion chamber 4 of the main body cylinder 1. Furthermore, a cone 7 made of heat-resistant steel is attached to the other end side of the main body cylinder l constituting the burner main body through flanges 14Bg and 8 with bolts and nuts, and the tip thereof forms an ejection hole 9.

1- The high velocity burner uses a part of the air supplied from the supply hole 6 for combustion in the combustion chamber 4, and uses the air supplied from the supply hole 6, that is, the dilution air, to heat the combustion scum to a predetermined temperature. 80-200m/s by controlling temperature and rolling
Heating is performed by blowing out hot air from the blowing holes 9 at a high speed of ec and circulating this high speed hot air in the furnace.

When drying and preheating a large complex furnace using the high-velocity burner described above, high-velocity hot air is circulated within the furnace, and excess fuel is introduced into the furnace to burn while consuming the air inside the furnace. The work time is shortened by heating the parts at once and avoiding localized heating conditions.

As mentioned above, high velocity burners are used for the following reasons. In other words, when heating with a normal radiation burner, heat transfer is hindered by a thin film of gas that exists at the interface between the heated object and the hot air.
When using a high-velocity burner, the high-velocity hot air removes the scum film on the boundary surface and brings the hot air into direct contact with the object to be heated, greatly improving heat transfer. To become. Therefore, compared with the general method using a width type burner, the method described above allows for much easier uniform heating and can shorten the working time.

However, the method described above has the following drawbacks. For example, when heating a glass melting furnace, when the inside of the furnace is at a low temperature of about 600 degrees Celsius or less, the melting temperature is delayed by +1 at the hearth part than at the ceiling part due to the lack of low-temperature hot air, and the temperature rises by about 10 degrees.
A temperature difference of 0°C occurs, and the temperature inside the furnace becomes unrestricted. Also,
In the heat storage room, the hot air does not reach the edges of the chenokur bricks, so it is necessary to forcibly draw it in by driving the exhaust gas fan. Therefore, it is not possible to meet the demand for high accuracy of furnace operating conditions. Furthermore, since excess fuel is burned in the furnace, the fuel outlet 11 costs a lot, and odor may be generated due to combustion gas components.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a heating method for a single-industry furnace that can achieve high precision in furnace operation conditions, energy saving, and improvement in the working environment.

1-A method for heating a furnace according to the present invention uses a high-velocity burner having a cone that blows out hot air and an external cone that is installed outside the cone and blows out diluted air. supplies most of the dilution air from the external cone to generate low-temperature hot air and maintain the furnace pressure on the positive side, and as the furnace temperature decreases to 1-01, the dilution air is supplied from the external cone faster. It is characterized by reducing the

According to such a method, especially when the inside of the furnace is at a low temperature, it is possible to supply hot air of relatively low temperature C and temperature control of 1 liter, so that the furnace operating conditions can be highly accurate. Furthermore, since excess fuel is not burned, energy savings and improvement of the working environment can be achieved.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 4. In addition, Fig. 1 (a) already mentioned in Fig. fj%2
Components that are the same as those in (b) and (b) are designated by the same numbers and their explanations will be omitted.

FIG. 2 is a cross-sectional view of a high velocity burner used in an embodiment of the invention. That is, in the conventional high-velocity burner, the cone 7 made of heat-resistant steel was attached to the burner body consisting of the main cylinder l and the inner cylinder part 2.The outer cone 10 made of heat-resistant #1 was attached to the outside of the cone 7 of the conventional high-velocity burner. It has a well-designed structure. This external cone 10 is provided with a dilution air supply hole 11 for supplying high speed air from a dedicated blower.

Drying/heating in a one-day furnace using the high velocity burner 412 having such a configuration is carried out as follows. In other words, the required number of high-velocity burner seals mentioned above are placed at appropriate positions in the furnace body, and the high velocity hot air from above the burner is circulated in the furnace to heat the II temperature according to the predetermined heating schedule. do. Here, this heating schedule is divided into two parts depending on the heating temperature, and the drying period (from the film temperature to about 3°C).

°C), early preheating (approx. 00°C to approx. 600°C), middle preheating (approximately 00°C to approx. 1100"C), late preheating (approximately 1
100°C to operating temperature). First, during the dry period, while avoiding complete combustion of the fuel from the fuel nostle 5 in the combustion chamber, diluted air is supplied from an external cone to the combustion chamber to maintain the pressure inside the furnace at a positive lead (higher than atmospheric pressure).
While maintaining the predetermined pressure, the temperature is increased to A, and the process moves to the first stage of preheating. Next, in the middle of preheating, the heating temperature is J'l
At the same time, the combustion gas velocity above the burner increases, and the furnace pressure gradually decreases to L-'il. Therefore, the dilution air velocity from the external cone 10 is gradually reduced to about 1100'C while maintaining the predetermined furnace pressure. At the same time, the preheating by the high-velocity burner 1λ is completed, and the operation burner installed in the furnace body is ignited to move to the latter half of preheating, and the temperature is increased to the operating temperature A, and operation begins.

In this manner, the high velocity burner 11 is used during the drying period, early preheating period, and late preheating period of the heating schedule, and is always operated in a complete combustion state during these periods. In particular, it is easy to maintain the pressure inside the furnace at low temperatures during the drying period and early preheating period, and the temperature distribution inside the furnace can be maintained uniformly.

In fact, as shown in FIG.
High velocity in the corner - on the burner! , blower 14 for diluted air, blower 15 for diluted air, fuel supply device 16, thermocouple 17.17. A total of 414 sets of control devices 18, etc. were arranged, one set each, LPG was used as the fuel, and the heating schedule was such that the temperature inside the furnace, the pressure inside the furnace, and the diluted air inlet had the relationships shown in Figure 4. Furnace-1 - The completed furnace body was dried and preheated. As a result, it became easy to adjust the temperature and pressure inside the furnace, and it became possible to keep the temperature difference between the ceiling and the hearth within 30°C. In addition, it was possible to heat the F section of the heat storage chamber and the flue according to the schedule without using the υ1 cast fan.

In this way, it was possible to uniformly heat every corner of the furnace, making it possible to achieve high precision in drying and preheating operations. Additionally, fuel consumption is reduced by approximately 20% compared to conventional methods.
In addition to reducing fuel consumption, the generation of combustion gas odor could also be prevented.

In the above embodiment, the high velocity burner cone 7 and external cone 10 shown in FIG. C or more 1. It is possible to continue heating until the late preheating stage. In this case, if the operating temperature is low, the furnace can be operated with only a high velocity eight without having to attach a rotary type bender for operation to the furnace body.

Furthermore, although a large glass melting furnace was described in Example 1-1, highly efficient drying and P heating can be performed in other hot blast furnaces by employing the method of the present invention.

Furthermore, the method of the present invention can be effectively applied to drying during firing of bricks, removing distortion from large welded structures, annealing cast products, drying monolithic refractories, drying the interior coating of vessels, etc. For example, when the method of the present invention is used to dry bricks during firing, the temperature inside the furnace can be made uniform, making it possible to pack brick molded bodies more densely than before.
Another effect is that the inside of the furnace can be used effectively.

As described above, the industrial furnace heating power method of the present invention has remarkable effects such as increasing the precision of furnace operation conditions, saving energy, and improving the industrial environment.

[Brief explanation of drawings]

Claims (1)

[Claims] A high-velocity burner has a cone that spouts hot air and an external cone installed outside the cone that spouts diluted air, and when the temperature inside the furnace is low, Martian diluted air is supplied from the external cone. 1. A method for heating an industrial furnace, comprising generating low-temperature hot air and maintaining the pressure inside the furnace on the positive side, and reducing the supply of dilution air from the external cone as the temperature inside the furnace increases.