JPH039170B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for controlling the flow rate of oxygen in a sintering machine, and more specifically, the present invention relates to a method for controlling the flow rate of oxygen in a sintering machine, and in particular, a method for controlling the flow rate of oxygen in a sintering machine, which has succeeded in increasing the productivity of sintered ore by efficiently supplying the minimum necessary amount of oxygen. The present invention relates to an oxygen flow rate control method. [Prior Art] FIG. 2 is a schematic explanatory diagram showing a typical configuration example of a Dwight Lloyd sintering machine. As shown in FIG. 2, in the Dwight Lloyd type sintering machine, the raw material supplied from the raw material supply section 12 is transferred to the ignition furnace 4 while sucking air from above from the lower part of the sintering head 13 into which the raw material layer is charged. The coke powder mixed in the raw material is ignited to sequentially burn the coke powder mixed in the raw material, thereby promoting sintering and melting reactions between the raw material ore particles. Therefore, the productivity of sintered ore in a sintering machine largely depends on the combustion rate of the coke breeze. For this reason, various methods have been tried to improve the combustion rate of coke breeze. For example, there is a method of increasing the amount of air passing through the sintering raw material layer, or a method of increasing the amount of air passing through the sintering raw material layer, A method has been proposed in which the gas penetrating the layer is oxygen-enriched air. [Problems to be Solved by the Invention] In addition, in the sintering machine, in order to maintain the pressure in the flue 14 constant, as shown in FIG. I am trying to adjust the opening degree. However, the amount of air that passes through the sintered bed 13 from top to bottom and is sucked into each wind box 2 changes depending on the ventilation resistance of the raw material layer on each sintered bed 13 located at the top of the wind box 2. do. The ventilation resistance of the raw material layer changes from moment to moment in response to changes in the filling state of the raw material, the raw material particles, etc., and the amount of exhaust gas flowing through each wind box 2 is constantly changing. When supplying oxygen to the sintering raw material on the sintering head 13, the total oxygen supply amount is adjusted by keeping the supply gas flow rate constant and controlling the oxygen content in the supply gas. When this method is adopted, not only the amount of air passing through the sintered bed 13 changes due to the reasons mentioned above, but also the oxygen concentration, so these two changes overlap and the amount of oxygen supply layer becomes extremely large. This will result in significant changes and a significant drop in operational stability. On the other hand, the raw material filling height on the sintering bed 13 is 300~
Since the length is about 800 mm, the time for gas such as air to pass through the sintered bed 13 is extremely short, only about 1 second. Furthermore, coke breeze does not start a combustion reaction with oxygen unless it is above 600°C, and the time that air and coke breeze come into contact at temperatures above 600°C is extremely short, so the efficiency of the combustion reaction is extremely low. In such a sintering process, not all of the added oxygen contributes to the combustion of coke breeze, and the amount of oxygen supplied is unstable, so the amount of oxygen must be slightly excessive. Under normal operating conditions, excess oxygen is wastefully discharged. As mentioned above, in the conventional technology, no consideration is given to the optimal oxygen addition range in which oxygen can be used effectively, and from this perspective, it is necessary to develop control technology to maintain the optimal amount of oxygen addition. desired. Therefore, in view of the above-mentioned current situation, an object of the present invention is to efficiently supply oxygen and reduce the production cost of sintered ore. [Means for solving the problem] The present invention measures the introduction flow rate of combustion oxygen in a combustion oxygen supply zone and the total flow rate of exhaust gas in the wind box related to the zone, and calculates the introduction flow rate of combustion oxygen and exhaust gas. The gist of this is that sintering is performed while controlling the ratio to the total flow rate to be less than 0.15. [Function] The present invention is constructed as described above, but the point is that in a sintering machine 1 as shown in FIG.
The operation is carried out while adjusting the flow rate of combustion oxygen introduced into the reactor. The adjusted oxygen introduction flow rate is set so that the ratio α between the oxygen introduction flow rate and the exhaust gas flow rate in the wind box 2 into which oxygen is introduced becomes a predetermined value. The value of the ratio α is
This is an important requirement for improving the utilization efficiency of introduced oxygen and further improving the productivity of sintered ore, and as described below, it is necessary that it be less than 0.15. FIG. 3 is a graph showing the relationship between α and the oxygen utilization efficiency, and the oxygen utilization efficiency is expressed by the following equation (1). In equation (1), "the amount of oxygen that contributed to the combustion of coke breeze" is a value determined by numerical calculation based on the measured value of the CO ₂ concentration in the exhaust gas flow rate. Oxygen utilization efficiency = Amount of oxygen that contributed to the combustion of coke breeze [Nm ³ /H] / Oxygen introduction flow rate [Nm ³ /H] x 100 (%
)......(1) As is clear from FIG. 3, as the oxygen introduction flow rate increases and α (oxygen introduction flow rate/total exhaust gas flow rate) increases, the oxygen utilization efficiency decreases. Especially α
When becomes 0.15 or more, the decrease in oxygen utilization efficiency becomes remarkable. From the results shown in Figure 3, the following can be considered. That is, the combustion of coke breeze does not depend only on the introduced oxygen concentration, but is influenced by the reaction contact time between oxygen and coke breeze and other factors. This means that in actual operation of a sintering machine, considering that the basic unit of oxygen for combustion is generally expensive, it is necessary to reduce the manufacturing cost of a sintering machine by using oxygen within a range with high oxygen utilization efficiency. This suggests how important it is to operate the sintering machine. [Example] FIG. 1 is a schematic explanatory diagram of a Dwight Lloyd type sintering machine 1 (hereinafter simply referred to as sintering machine) configured to carry out the method of the present invention. In Fig. 1, 3 is the main exhaust flue, 5 is the exhaust gas flow meter, 6 is the oxygen blowing hood, 7 is the oxygen introduction pipe, 8 is the oxygen flow rate adjustment valve, 9 is the oxygen flow meter, and 10 is the exhaust gas flow rate meter. The calculation adder 11 is a ratio setting device for the introduced oxygen and the exhaust gas flow rate. Other parts corresponding to those of the prior art shown in FIG. 2 are given the same reference numerals. The oxygen blowing hood 6 corresponds to the combustion oxygen supply zone, and the oxygen blowing hood 6 may be placed on one wind box 2, but it may be placed on the wind box 2 at multiple locations (three locations in the embodiment). There is no problem even if it is on top. A method for controlling the flow rate of oxygen introduced into the sintering machine 1 will be explained. The exhaust gas flow rate of each wind box 2 related to the oxygen blowing hood 6 is measured by a flow meter 5. The exhaust gas flow rate of each wind box 2 measured by the flow meter 5 is added by an arithmetic adder 10, and the total exhaust gas flow rate in the wind box 2 into which oxygen is introduced is measured.
Arithmetic adder 10 is connected to a ratio setter. On the other hand, the combustion oxygen supplied to the sintering bed 13 is supplied to the oxygen blowing hood 6 via the oxygen introduction pipe 7, the oxygen flow rate control valve 8, and the oxygen flow meter 9. A total of 9 are connected to the ratio setter 11. The oxygen flow rate in the oxygen flow meter 9 is adjusted by the oxygen flow control valve 8 so that the ratio α between the oxygen flow rate and the exhaust gas flow rate becomes a value set by the ratio setting device 11. Here, the value set by the ratio setting device 11 is a value at which the ratio α0.15 between the oxygen introduction flow rate and the exhaust gas flow rate is less than 0.15, as described in connection with FIG. 3 above. In this way, the ratio between the oxygen introduction flow rate and the exhaust gas flow rate can be kept constant at all times. The present invention ultimately controls the oxygen introduction flow rate so that the value of α is less than 0.15.
Needless to say, the exhaust gas flow rate exists in addition to the oxygen introduction flow rate as a factor that influences the value of α. The exhaust gas flow rate also depends on the filling state of the sintering raw material, the raw material particles, and other requirements. Therefore, in the present invention, the requirements for controlling α to be less than 0.15 are not limited to the oxygen introduction flow rate, but must also take into consideration the various other requirements mentioned above. Table 1 shows the results of actual operation using the sintering machine 1 shown in FIG. As is clear from the results in Table 1, when α becomes 0.15 or more, the oxygen consumption rate deteriorates significantly to 40Nm ³ /T.
It is understood that less than 0.15 is optimal.

[Table] [Effects of the Invention] As described above, by implementing the method of the present invention, it becomes possible to maintain high oxygen utilization efficiency in the sintering machine, and economical oxygen addition operation can be carried out. This makes it possible to reduce the unit weight, and thus greatly contributes to improving the productivity of sintered ore.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of a sintering machine 1 configured to carry out the method of the present invention, and FIG. 2 is a schematic explanatory diagram showing a typical conventional technique of a Dwight Lloyd type sintering machine.
FIG. 3 is a graph showing the relationship between ratio α and oxygen utilization efficiency. 1... Sintering machine, 2... Wind box, 3... Main exhaust flue, 4... Ignition furnace, 5... Flow meter, 6... Oxygen blowing hood, 7... Oxygen introduction piping, 8... Oxygen flow rate adjustment valve, 9...Oxygen flowmeter.

Claims (1)

[Claims] 1 In the oxygen flow rate control method for a Dwight Lloyd sintering machine, the introduction flow rate of combustion oxygen in the combustion oxygen supply zone and the total flow rate of exhaust gas in the wind box related to the zone are measured, and the introduction flow rate of combustion oxygen and exhaust gas are measured. A method for controlling an oxygen flow rate in a sintering machine, characterized in that sintering is performed while controlling the ratio to the total flow rate to be less than 0.15.