JPH0317212A - Method for operating blast furnace - Google Patents

Abstract

PURPOSE:To increase blending rate of small grain sintered ore without obstruction to gas flow in a furnace by operating a movable armor so that ratio of fluidized part area and inner volume of the furnace obtd. from stock line picture with a dark field camera comes to the specific value. CONSTITUTION:The TV camera in the furnace opening part is used and the small grain sintered ore is blended and charged to execute the blast furnace operation. Then, the stock line is photographed with the dark field camera arranged at the furnace opening part. The picture is processed with a computer to obtain the area of the fluidized part. The movable armor is operated so that the ratio of the fluidized part area and the inner volume of the furnace comes to 0.1-0.3X10<-3>/m. By this method, the obstruction of gas flow caused by charging of the small grain ore to the center of furnace or uneven distribution thereof to the circumference of the furnace wall is prevented and the blending rate of the small grain sintered ore can be increased.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method of operating a blast furnace in which small-grain sintered ore is mixed and charged. [Conventional technology] Conventionally, iron ore and sintered ore (referred to as small-grained ore) with a size of 5 Ilffi or less were sieved through a screen and used as raw materials for sintering, as they impeded the permeability of the blast furnace. In recent years, a technology for using small grain ores of 2 to 5 mm in blast furnaces has been developed and put into practice for the purpose of reducing raw material costs. This technology includes the following: Mixed charging in which fi + small grain ore is mixed and charged with conventional ore. {■Separate charging that cuts small ore and conventional ore from separate hoppers at the same time.

(3) Charging by particle size, in which small grain ore is charged singly into the conventional ore layer. [Problems to be Solved by the Invention] However, in the conventional charging method, as the amount of small ore increases, the angle of repose becomes smaller due to the influence of the gas flow, and the small ore is charged to the center of the furnace, causing the central gas flow to become smaller. There is also the problem that small ore particles leak around the furnace wall, suppressing the surrounding gas flow and causing wall formation. Therefore, the blending ratio of small ore to the main raw material was up to 10%. The purpose of this invention is to provide a method that allows a larger amount of small-grain ore to be mixed than before. [Means for Solving the Problems] The present invention aims to achieve the above object, and in a blast furnace operation method using a furnace mouth TV camera, when mixing and charging small grain sintered ore, the furnace mouth part The stock line was photographed with a night vision camera installed in the room, and the image was processed to determine the area of the fluidized part, and the ratio of the area of the fluidized part to the volume inside the furnace was 0.1 to 0. This is a blast furnace operating method characterized by operating a movable armor so that the ratio is 3 x 10-'/m. [Function] As shown in Figure 2, when the ratio of the area of the fluidized section to the volume inside the furnace is 0,
．． When it is smaller than I x 10-'/m, the central flow becomes weaker and the ventilation resistance coefficient exceeds the operational limit value. In addition, the ratio of the area of the fluidized part to the volume inside the furnace is 0.3X10
-'/m, the ventilation resistance coefficient similarly exceeds the operational limit value. Therefore, the ratio of the area of the flowing part and the volume inside the furnace obtained by the furnace mouth TV camera is 0.1 to 0.3X.
By operating the movable armor so that the ratio is 10-'/m, it becomes possible to mix more small-grained sintered ore than before. [Example] The method of the present invention will be explained in detail below. Figure 1 shows the stock line being imaged with a television camera installed at the mouth of the blast furnace. 1 is the furnace mouth, 2 is a night vision camera installed at the furnace mouth l to photograph the stock line, 3 is the stock line, and 4 is the area where the charge is fluidized by the gas flow. The inventors conducted a test to increase the proportion of small sintered ore and investigated the relationship between the proportion of small sintered ore and the ventilation resistance coefficient. FIG. 4 shows this result. It is known that in order to perform stable blast furnace operation, the ventilation resistance coefficient must be 3.5 or less, and from Figure 4, the proportion of small sintered ore should be
It was found that it is necessary to keep it below 20%. The ventilation resistance coefficient here is . Next, the inventors analyzed (or processed) the image of the stock line taken by the furnace mouth camera using a computer to determine the area of the flowing section, and calculated the area of the flowing section (represented by symbol A) and the internal volume of the furnace.
The relationship between the ratio of 〉 (denoted by the symbol D) and the ventilation resistance coefficient was investigated. Figure 2 shows this result graphically. A/D is 0
．． If it is less than 1, the central flow will be weak and the pressure drop will increase, the ventilation resistance coefficient will exceed the operating limit value (3.5), and the A/D will be 0.
．． If it exceeds 3, the center flow becomes too strong and the pressure drop increases.
It was found that the ventilation resistance coefficient exceeded the operational limit value. From this graph, in order to make the ventilation resistance coefficient 3.5 or less,
It can be seen that /D should be within the range of 0.1 to 0.3. FIG. 3 is a graph showing the relationship between A/D and small sintered ore blending percentage when the operation is performed with the ventilation resistance coefficient below the operating limit value (3.5). From this graph, A/D is 0.1
It can be seen that if the value is within the range of ~0.3, up to 30% of small grain sintered ore can be blended. The present invention was invented based on the above findings.
That is, the image signal taken by the furnace night vision camera 2 installed at the furnace mouth part 1 is input into a computer, the image is analyzed, and the area of the flowing part of the stock line 3 is determined, and this flowing part area A and the furnace The ratio of internal volume D is displayed on the CRT display, and if A/D falls outside the range of 0.1 to 0.3, the movable armor is operated to bring it within the range. Although the above embodiments have been described with respect to small-grained sintered ore, the same applies to the case of small-grained ore. [Effects of the Invention] The present invention determines the area of the flowing part using a night vision camera at the furnace entrance, monitors the ratio of this flowing part area to the internal volume of the furnace using a CR'T display, and adjusts the movable armor so that it falls within a predetermined range. This method has the effect of being able to mix more small-grained ore and small-grained ore than with conventional methods.

[Brief explanation of the drawing]

Claims (1)

[Claims] In a blast furnace operation method that uses a TV camera at the furnace mouth, when mixing and charging small sintered ore, the stock line is photographed with a night vision camera installed at the furnace mouth, and the image is processed to determine the flow section. Calculate the area, and make sure that the ratio of the area of the fluidized part to the volume inside the furnace is 0.1 to 0.3 x 10^-^3/m.
A blast furnace operating method characterized by operating a movable armor.