JPS62263912A - Method for recovering ldg of hermetic converter - Google Patents

Abstract

PURPOSE:To recover a converter gas at a high yield by blowing an inert gas in such a manner that a pressure difference between inside and outside skirts attains a specific value or below at the time of hermetically closing the gas generated from the converter by the double skirts and recovering such gas. CONSTITUTION:The converter gas contg. much CO and Fe2O3 powders in the timing when a decarburization reaction is active is recovered at a high recovery rate by hermetically closing the part between a converter throat and flue with the double skirts without escaping said gas to the outside and without allowing CO to be burned by the air intruded from the outside at the time of steel making refining by the top blown converter. The inert gas such as N2 or Ar is blown between the skirts to maintain the difference between the internal pressure P0 of the inside skirt and the internal pressure P0' of the outside skirt at <=2mmH2O when said difference increases to >=2mmH2O. the gas is thus recovered without allowing the CO-component to be burned by the air intruded from the outside and conversely without allowing the converter gas to dissipate from the skirts to the outside and to burn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling the pressure inside a converter furnace during operation by sealing the space between the mouth and the skirt of a converter furnace.

=1- [Prior art] In general, the gas generated by converter blowing is mainly bulky CO gas containing fine iron oxide powder, and it takes 12 to 18 minutes of the 30 to 40 minute steelmaking time. The gas is produced intermittently only during blowing work, and it is a large amount of gas. Methods for processing this gas are broadly divided into combustion methods and nodule combustion methods.

Among these, the non-combustion method uses a skirt between the converter mouth and the flue to prevent the converter waste gas from being combusted. Generally, it is collected unburned through a wet dust collector such as No. 2.

FIG. 4 shows a method of sealing the converter in these non-combustion recovery methods.

The recent upward converter using the LD method is as shown in Figure 4.
Conventionally, the converter has a double skirt, compared to one, and the degree of sealing is improved compared to the conventional converter.

However, due to the deformation of the furnace opening and the deformation of the skirt itself, some gaps may occur. In addition to these deformations, the generation of waste gas due to blowing is not necessarily constant and fluctuates within a short period of time. This variation can easily be covered by the PA damper alone.

Mechanical sealing alone is not sufficient to deal with the above-mentioned deformation and instantaneous fluctuations in gas generated from inside the furnace, and loss occurs due to combustion and blow-out of LDG due to air entrainment. .

Problems to be solved by the invention] The purpose of the present invention is to improve the sealing degree of the closed converter in the conventional 4D method and increase the recovery of LDG (which penetrates the recovery power in the LD method). shall be.

[Means for solving problems]

The present invention provides a gas recovery method for a converter sealed with a double skirt 1, in which pressure fluctuations between the inner and outer skirts of the double skirt are measured at at least two locations,
141) G recovery power of a closed converter in which the difference between the measured value and the furnace pressure is controlled by blowing inert gas? It's gone.

Specifically, the pressure difference between the pressure fluctuation between the inside of the double skirt and the furnace pressure is 21.
II. This is an LDG recovery method using a closed converter in which inert gas is blown in to keep the temperature below 1°0.

[Effect]

As shown in Fig. 1, the LDG recovery method of a closed converter according to the present invention is based on the pressure fluctuation (PG') between the inner and outer skirts.
is measured at two or more tube locations and compared with the conventional furnace pressure Po. In that case, when lp o P o'l≧2IlIIIIII20, inert gas is blown between the skirts from two or more locations. As the inert gas, J, Ar gas, etc. can be used.

Like this Po and P. By controlling the pressure difference between the air and the air by blowing inert gas, it is possible to prevent blowout loss and combustion loss due to air entrainment. This allows L
It is possible to increase the recovery of DG.

Next, embodiments of the present invention will be described.

〔Example〕

FIG. 1 is a detailed explanatory diagram of the present invention.

As shown in Figure 1, the pressure fluctuation (Po') between the inner and outer skirts provided in the upper part of the closed converter in the LD method was measured at two or more points, and the pressure inside the furnace was determined. ■). Compare with. In that case, IF' o-P o'
When l≧2H20, N2 as an inert gas is blown between the skirts from 2@H20.

Figure 2 shows the difference lp (+
--It is an explanatory view showing the state of P o'1 mm jl 20 and L DG.

If < , 1p0-p0'l>o is not shown in Figure 2, then
LDG ballooning phenomenon occurs, IP o-P o'
If l < o, air is drawn in between the skirts and LDG
Secondary combustion occurs.

Therefore, P0' is measured and the value is 1p0-river].

By adjusting with an inert gas such as N2 gas so that '1≧21)III20, the recovery loss of LDG can be minimized.

FIG. 3 shows the histogram of the LDG gas recovery coolant unit (NIn37T) for the method of the present invention and the conventional method.

As shown in Figure 3, in the case of the method of the present invention +17 (Nm3
/T) is the gas recovery unit, which is 1) for the conventional method.
For the gas recovery unit of 2 (No + 3/T), 5 (
It is clear that the recovery of LDG (Nm3/T) will be increased.

〔Effect of the invention〕

According to the LDG recovery method in a closed converter of the present invention, the degree of sealing is improved, and losses due to secondary combustion and blow-off due to air entrainment are reduced, and the environment is also improved.

[Brief explanation of drawings]

Fig. 1 is a detailed explanatory diagram of the present invention, Fig. 2 is an explanatory diagram showing the pressure fluctuation between the inner and outer skirts, the pressure difference with the furnace pressure, and the state of the LDG in an embodiment, and Fig. 3 is an explanatory diagram showing the state of the LDG. FIG. 4 is an explanatory diagram of a conventional method of sealing a converter.

Claims (2)

[Claims] (1) In a gas recovery method for a converter sealed with a double skirt, the pressure fluctuation between the inside and outside skirts of the double skirt is measured at at least two locations, and the difference between the measured value and the pressure inside the furnace is calculated. A method for recovering LDG in a closed converter, characterized by controlling by blowing inert gas. (2) The sealing according to claim 1, characterized in that inert gas is blown so that the pressure difference between the pressure fluctuation between the inner and outer skirts of the double skirt and the pressure inside the furnace is 2 mmH_2O or less. Converter LDG recovery method.