JPS61153218A - Cooling method of lance for blowing powder into blast furnace - Google Patents

Abstract

PURPOSE:To always maintain a lance in a sound state by feeding a cooling gas from a separately provided cooling gas piping for cooling the lance to the lance when the supply of a carrier gas to the lance of which the top end is projected into a blow pipe is interrupted. CONSTITUTION:High-temp. air for blasting is blown through the blow pipe 15 into a blast furnace 17 through a tuyere 16. The lance 1 attached to the pipe 15 is connected to a transport piping 2 having an on-off valve 8 and the cooling gas piping 7 having a check valve 6 and an on-off valve 7 in this case. The valve 8 is therefore closed immediately when the supply of the cooling gas of the piping 2 stops. On the other hand, the valve 7 of the cooling gas line is opened to supply the cooling gas (for example, air) to the lance 1. Accidents of the blow-off of the high-temp. gas from the inside of the furnace owing to damage of the lance and the downtime of the blast furnace for the purpose of exchanging the damaged lance are thus eliminated and life of the lance is extended.

Description

Detailed Description of the Invention (Industrial Application) The present invention provides a lance that is convenient for cooling powder such as pulverized ore or pulverized coal when gas stops flowing through the tuyere. This is a proposal regarding cooling technology.

Conventional technology) Conventionally, in the operation of blast furnaces, carrier gas is used to collect various powders such as pulverized coal, coke powder, and iron ore in order to properly manage the reactions in the furnace and to partially replace the fuel. stone powder,
Limestone powder, Mn ore powder, etc.

The technology used is to blow into the furnace through tuyeres.

The powder to be supplied into the above-mentioned blast furnace is blown through a blowing lance that penetrates the wall of the blow pipe and has its tip opening positioned approximately at the center of the pipe. Using such a lance, it is possible to blow high-concentration powder, which is transported by air supplied through the transport piping and also serves as lance cooling, up to the tip of the tuyere (C raceway) inside the furnace. It becomes like this.

Now, inside the blow pipe, there is a high temperature (9001"C ~
1800°C), high speed (150~180 m7'sec
+, high pressure (2.0~4.0 kg 7cm2G) (
D The blast air is drained, so the tip of the lance is constantly exposed to the blast air, and it is constantly exposed to high temperatures and
They will be placed under harsh conditions under high pressure.

...Conventionally, such lances have been made of materials such as heat-resistant alloys, heat-resistant, high-strength ceramics, etc. Although these materials have high heat resistance, at least the portion that protrudes into the blowpipe is subject to physical control. Cooling is essential, and in reality, it is cooled using a carrier gas for powder transportation.

The reality is that

(Problems to be Solved by the Invention) Now, regarding such a powder injection lance, when powder injection into the furnace is stopped, or when the equipment, including powder clogging in the transportation piping, etc. When the supply of the carrier gas having a lance cooling function is stopped due to a failure or the like, the lance is directly exposed to high temperature.

In short, the above-mentioned lances are usually constructed of heat-resistant materials that are susceptible to thermal collisions, and therefore the supply of cooling gas passing through the lances must not be stopped even temporarily, so transport piping Although it is also necessary to detect clogging inside, conventionally no consideration has been given to this point.

(c) Means for Solving Problems) The present invention enables the lance to be immediately removed when the supply of carrier gas to the lance is cut off, i.e. when the powder injection is stopped, and when the transport piping is clogged with powder. Another one just before.

In order to cool the lance, cooling gas was sent to the lance from a cooling gas pipe installed in the lance. The cooling gas is fed into the lance manually or automatically.

Further, although air is normally used as the cooling gas, N2 gas or steam may also be used.

In addition, as a main means of solving the problem, the present invention also employs a method of (1) detecting powder clogging in the transportation pipe as necessary, and (2) cooling the lance with cooling gas based on that information.

(Function) FIG. 1 shows an embodiment of the lance cooling method according to the present invention, in which a powder transport pipe 2 and a cooling pipe 8 are connected to a lance 1 for blowing. 0N-OF
F valve 8 is installed, and 0N- is installed in the cooling pipe.
A check valve 6 is provided to prevent the OFF pulp 7 and powder from flowing into the cooling pipe from the lance 1.

On the other hand, the powder is stored in an injection tank 9 having a load cell IO, and is discharged in high concentration by pressurized gas supplied from the pressurization line 5.

It is taken out and transported to the confluence point A of the transport pipe 2.

Here, the powder is transformed into a low-concentration powder by the transport gas supplied from the transport gas line 4 and guided to the nozzle 1.

The pressurized gas line 5 and the transport pipe 2 have pressure and force sensors 12 and 11, respectively, and the differential pressure between the pressure sensor 12 and the pressure sensor 11 is connected to a differential pressure oscillator 18.

FIG. 2 shows the state in which the powder injection lance 1 is attached to the blow vibe 15, and the blow vibe 1-15 is connected to the tuyere 16.

(Example) An example of the present invention will be described with reference to the drawings, particularly a case where powder clogging occurs in a pipe. The high-temperature blowing air passes through the blow vibe 15 and enters the blast furnace 1 from the tuyeres 2...16.
It's blown away. 1 lance 1 for powder injection is attached to a blow vibrator 15, and includes a transport pipe 2 having an 0N-OFF valve 8, a check valve 6, and an 0N-OFF valve 7.
It is connected to a cooling gas pipe 7 having a cooling gas pipe 7. Therefore,
When the supply of the carrier gas in the transport pipe 1 pipe 2 is stopped, the 0N-OFF valve 8 is immediately closed, while the 0N-OFF pulp 7 in the cooling gas line is opened to supply cooling gas to the lance 1. .

In the present invention, when the transportation pipe 2 is clogged with powder, it is necessary to immediately detect the clog and switch the supply from the carrier gas to the cooling gas.

The clogging was detected by the following method.

Example 1 Highly concentrated powder is guided from the injection tank 9 to the transportation pipe 2 via the pressurizing gas line 5. On the other hand, at point A, carrier gas is blown into the transport pipe 2 from the carrier gas pipe 4.

The source pressures of pipes 4 and 5 are almost equal, but during normal blowing, the pressure of pressure gauge 11 P□□-... and the pressure of pressure gauge 12 "IJ"
Between P, (P□, [ΔP 11-P -P
There is a relationship of ΔP>01.

However, if piping 2 is clogged, Pyu 1 ” 12 (
It becomes ΔP-01. Therefore, this ΔP0, that is, the differential pressure between PI3 and P1□ is detected, and when this becomes -1 below the set pressure, the valve 8 is closed and the valve 7 is opened to switch the gas.

Example 2 The flow rate Q of the flow meter 14 provided in the carrier gas piping 14 during normal blowing is adjusted to 1. When the 10 pipe 2 is clogged, the value becomes Q'-,0, so set an appropriate value Q in advance. is prepared, and the flow rate Q is Q. There is also a method of determining that the pipe is clogged when the following is reached, and switching the lance 1 to the carrier gas line 8.

Example 8 The weight of the injection tank 9 is detected by the load cell 10, and the change dw/dt between the reading W of the load cell 10 and time is detected, and when this dw/dt becomes below the set value, the This method assumes that the line is blocked and switches the line.

By supplying cooling gas in a separate pipe in a timely manner, there was no longer any burnout or damage to the tip of the lance.

C) Effects of the Invention As explained above, by carrying out the present invention, it is possible to always maintain the lance in a healthy condition, thereby preventing accidents such as "hot gas blowing out from inside the furnace due to damage to the lance" and damage. Temporary shutdown of the blast furnace to replace the lance was eliminated, and as a result, the life of the lance was extended, resulting in significant safety and cost benefits.Also, the powder injection operation Can be implemented stably.

[Brief explanation of drawings]

FIG. 1 is a control system diagram of a device used to carry out the cooling method of the present invention, and FIG. 2 is a sectional view of the lance attachment portion.

Claims (1)

[Claims] 1. When the necessary powder introduced from a lance whose tip protrudes into the blow pipe is blown into the blast furnace through the tuyere via the carrier gas, when the supply of the carrier gas from the transport pipe is interrupted. A method for cooling a lance for blowing powder into a blast furnace, characterized in that cooling gas is fed into the blow pipe from a cooling gas pipe provided as a separate pipe.