JPS5938310A - Cooling method of furnace inside after blowing out of blast furnace - Google Patents

Abstract

PURPOSE:To cool safely the charge in a blast furnace after blowing out in a short time by allowing the charge in the blast furnace to descend down to a tuyere level then feeding water through tuyere nozzles and blasting ordinary- temp. gas contg. oxygen through the tuyeres. CONSTITUTION:The charge 1 in a blast furnace 2 is lowered down to the tuyere level 3 of the blast furnace and after molten iron is discharged from the furnace, water is fed through the blow nozzles 4 for blowing liquid fuel, etc. in the tuyere part and gas at ordinary temp. contg. 5-22% oxygen is blown through annular pipes 6 and blast branches 5. Water gas is formed by the reaction of red hot coke and water in the stage of the quenching by the water feeding. However, the water gas is burned safely by the continued partial combustion and the oxygen blown from blast systems. The combustion temp. is lowered by nitrogen at ordinary temp. blown simultaneously with oxygen.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for safely cooling the inside of a blast furnace, particularly the contents inside the furnace, in a short period of time after blowing down the blast furnace.

Conventionally, when cooling a blast furnace, the supply of the charge was stopped and a reduced-air operation was started, the amount of air blown was gradually reduced as the charging line descended, and then the taphole was opened and the After the above hot metal and Ig molten slag have flowed out from the taphole, the bricks at the bottom of the furnace are polled to create a horizontal hole that penetrates from outside the furnace to the bottom of the furnace, and the hot metal remaining in the hearth is drained from this horizontal hole. Exceptionally, stop the air blower after discharging. Next, high-temperature substances such as red-hot coke and slag remaining in the lower part of the m are scraped out by ordinary human methods.

■ Naturally burn coke and reduce residue within m to 100°C
After allowing it to cool, scrape it out of the furnace.

(Remotely controlled machines such as wireless bulldozers
700-800°C or higher).

■ After being forcibly cooled by water spraying from the top of the furnace, it is scraped out of the furnace.

■ By watering from the siding, stronger fr than the lower part of the domestic residue
After the ill cools down, scrape it out of the door.

However, the method (2) requires a period of 6 months to 1 year, which poses the problem of significantly extending the period for blast furnace repair. The method (2) using a remote-controlled machine involves technical problems because the machine is special, and the work takes about a week. Method (2) forcibly cools the residue in the furnace by sprinkling water, so the work can be completed in 1 to 3 days. However, the red-hot coke in the reactor residue reacts with water, resulting in C+H20→H2+ G
o) Water gas with a high risk of explosion is generated frequently, and the concentration of water gas in the reactor increases beyond the safe limit, which poses a major safety problem. Method (2) involves water-cooling the contents of the reactor from the periphery to the core, forcing the charge to be extinguished and cooled, and the water gas produced by the extinguishing cooling to be used as the spark remaining at the top of the charge. The coke is burned sequentially to prevent the water gas from entering the furnace, but the natural draft air source from the tuyeres causes the coke to burn.
There is a problem that the temperature inside the door increases excessively. This method also requires a cooling period of 1 to 3 days.

The present invention aims to safely cool the above-mentioned blast furnace contents that have been lowered to the tuyere level in a short period of time. The air blowing branch pipe is characterized in that when it is installed, water is injected from the nozzle in the paneling part, and normal temperature gas containing 5 to 22% oxygen at X7 is blown from the tuyere to cool the person inside the crime.

Hereinafter, the details of the present invention will be explained with reference to FIG. 1. First, the contents in the furnace (1) are F lowered to the level of the slats (3) of the blast furnace (2), and after the hot metal is discharged, the liquid state at the tuyere section is Blow nozzle (4
), etc. while injecting water at room temperature containing oxygen (oxygen concentration 5~
22ch) is injected. Here, it is difficult to reliably burn the CO gas generated in the furnace if the oxygen concentration in the cracked body injected from the tuyere is 5 degrees F or higher, and if the CO gas generated in the furnace exceeds 22 degrees F. Rapid combustion leads to an abnormal increase in the wetness of the gas inside the tank. During extinguishing and cooling by this water injection, red-hot coke and water react to generate water gas (C+H,,0→H2+CO).

However, due to continued partial combustion and oxygen blown in from the ventilation system, the water gas is safely combusted. Furthermore, the combustion temperature is lowered by the room-temperature nitrogen gas that is blown in at the same time as the oxygen. Here, the furnace top gas temperature and furnace top scum components can be adjusted by adjusting the above-mentioned (1) water injection wax, (2) oxygen concentration, and (2) gas flow rate, so that work can be carried out safely. Moreover, fP operation can be performed with the tuyere attached, so the process from blowing off to cooling can be completed in a short period of time.

As an example, in a high-temperature furnace with a furnace content of 2,600 doors (28 tuyeres), after the contents in the furnace were lowered to the tuyere and the hot metal was discharged, the siding and the blower branch pipe were left attached. ,
In addition to injecting 85 tons of cooling water per hour from the liquid injection nozzles at all tuyeres, room temperature gaseous nitrogen (oxygen concentration 18% remaining nitrogen) is also flowed from the tuyeres! 250 Nm'/m
The generation of carbon dioxide stopped after 12 hours. Assuming that this was a fact of the contents in the reactor and that the fire had been extinguished, water injection continued for about 8 hours, and the cooling work in the reactor was completed in 15 hours. According to this method, conventionally 1 to
The cooling period that used to take three days can be completed in 15 hours.

Figure 2 shows the water injection nostern from the tuyere, the average fence top gas temperature change, and the top gas components (co, c
o□e H210! ) is shown in a time chart. At the start of water injection, the furnace top gas temperature temporarily increases, but decreases over time. Furthermore, water gas (H2, CO) is kept extremely low over the entire period from the start of water injection to the end of cooling.

As is clear from the above explanation, the method of the present invention forcibly extinguishes and cools the contents in the blast furnace after blowing down the blast furnace with liquid (water) and gas (nitrogen, oxygen), so the cooling period is short;
Not only does it have a great effect on shortening the construction period for blast furnace renovation, but it also greatly improves work safety because the water gas generated by the extinguishing and cooling process can be completely combusted by the oxygen injected from the tuyeres. It is effective.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the lower part of the blast furnace, and FIG. 2 is a time chart. In the figure, 1...burden, 2...blast furnace, 3...tuyere,
4...Liquid state blowing nozzle, 5...Blower branch pipe, 6...
Annular tube. Applicant: Sumitomo Metal Industries, Ltd. Figure 1 Figure 2 Time of water injection start force 5 (H1

Claims (1)

[Claims] 1 After the contents in the blast furnace are lowered to the blade lorepel, water is injected from the nozzle in the tuyere section with the tuyere and air branch pipe attached, and room temperature gas containing 5 to 22 inches of oxygen is blown from the tuyere. A method for cooling the inside of a blast furnace after blowdown, which is characterized by cooling the contents inside the furnace.