JP3227196B2 - Exhaust gas treatment method for sintering machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating exhaust gas in a sintering machine for metallurgical ore, and more particularly to a method for desulfurizing exhaust gas in a sintering machine having an exhaust gas dividing and absorbing duct.

[0002]

2. Description of the Related Art Conventionally, as a method of treating exhaust gas from a sintering machine, Japanese Patent Application Laid-Open No. 54-48607 discloses a method in which an intake system of a sintering machine is divided into a front part and a rear part, and the exhaust gas in the front part is divided into a rear part. Discloses an attempt to reduce the amount of exhaust gas for desulfurization to increase the treatment efficiency.

However, in a normal sintering machine, 1
The SOx concentration in the exhaust gas in the second half of the third half is relatively high, and in the process of circulation to the second half of the bed, the SOx is concentrated and acid corrosion of ducts, heat exchangers and the like occurs. Further, the exhaust gas in the first half has low SOx, which is inefficient as a desulfurization treatment method.

Japanese Unexamined Patent Publication (Kokai) No. 60-155626 discloses that the entire exhaust gas system is divided into three parts in the longitudinal direction of the sintering machine to perform circulation and exhaust gas treatment corresponding to the properties of the exhaust gas.
From the latter half where high temperature exhaust gas is extracted, it circulates through the heat exchanger to the middle part of the sintering machine located at the top of the bed that is sucked into the desulfurization system, and the former half can perform conventional gas treatment. It is disclosed that there is an effect of preventing acid corrosion and reducing SOx generation.

[0005] However, none of these methods is an exhaust gas treatment method that grasps the characteristics of the SOx-containing pattern discharged from the bed based on the amount of S charged into the bed, and the concentration of SOx in the latter half is relatively low. high,
Even if it circulates in the upper part of the bed sucked into the desulfurization system, the concentration of the latter half SOx may further rise and become concentrated, and there is a problem that the attached equipment is corroded.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to carry out circulation and exhaust gas treatment in accordance with properties such as the temperature of exhaust gas and the concentration of SOx in a sintering machine more accurately, and to further improve equipment efficiency in desulfurization. It is an object of the present invention to provide a treatment method for improving and preventing acid corrosion of an exhaust gas treatment facility.

[0007]

DISCLOSURE OF THE INVENTION Exhaust gas from the sintering machine of the present invention
The treatment method is to remove the exhaust gas system from the first half of the bed of the sintering machine.
Discharges or circulates without passing through the
In the exhaust gas system from the middle part to the latter part, the system that discharges without passing through the desulfurization in the first part of the middle part , the system that discharges through the desulfurization device in the latter part of the middle part, and the exhaust gas from the latter part of the bed In the exhaust gas treatment method of the sintering machine divided into three systems, which are circulated to the intermediate part of the strand immediately after ignition, in the exhaust gas treatment method of the sintering machine , S in the compounded raw material and S in the gas sucked into the bed are treated.
All suction boxes corresponding to bed loading S expressed in sum
According to the change in the SOx content pattern for each,
Exhaust gas treatment from the second half of the middle
The system that discharges without passing through the
Under the bed corresponding to the system that discharges through the sulfur
Provide a perforated partition plate at an appropriate position in the duct, and
Adjust the porosity or remove the non-desulfurized system from the suction box.
And the suction system led to the desulfurization system is 30-50% from the first half
The area of the suction box is duplicated, and the SOx generation pattern
It is characterized in that the switching and adjustment are performed according to the operating conditions . to this
Therefore, a high desulfurization rate is ensured while maximizing the negative pressure just below the bed.
Is preserved.

[0008]

[0009]

Only the exhaust gas containing a high concentration of SOx is selectively discharged through the desulfurization unit, so that the processing efficiency of the desulfurization unit can be increased. Can improve the overall desulfurization rate.

[0010] The second half exhaust gas having a relatively high concentration of SOx is circulated to the intermediate portion of the strand immediately after ignition, thereby being adsorbed by the bed combustion zone and the wet layer, and further converted to a high concentration of SOx to be treated in a desulfurization system. You.

[0011]

FIG. 1 is a view showing an exhaust gas system for implementing an exhaust gas treatment method for a sintering machine according to the present invention.

In FIG. The suction gas system having the suction boxes Nos. 1 to 32 is provided with the suction boxes 4 in the positions of the preheating furnace 1 and the ignition furnace 2. 1 to 3 and the suction box No. 1 in the first half. It consists of a suction gas system from the intermediate bed to the latter half bed between 4 and 32, and this suction system from the intermediate bed to the latter half bed is divided into three suction systems. That is, the suction box No. corresponding to the heat retention furnace 5 is used. Nos. 4 to 5 and suction boxes No. 1 in the first half area 6 of the intermediate bed. 6 to 12 and a suction box No. 7 located in the rear area 8 of the intermediate bed. Second suction gas system 9 from the region 13-25
And the suction box No. located in the back half 10 of the bed. 2
It is divided into three systems, that is, a third suction gas system 11 from a region 6 to 32.

The exhaust gas in the suction gas system 3 in the first half of the bed is circulated and supplied from the feeder side circulation blower 13 to the rear area 8 of the intermediate bed via the preduster 12.

Exhaust gas from the first suction gas system 7 of the intermediate bed passes through an electric precipitator 14 and is discharged from a chimney 16 to the outside air by a main exhaust fan 15.

The exhaust gas from the second suction gas system 9 enters the desulfurization device 17 via the electric dust collector 14, where it is desulfurized and then combined with the first suction gas system and discharged from the chimney 16 to the outside air. You.

Exhaust gas from the third suction gas system 11 is supplied to the intermediate bed front half region 6 by the rear half circulation blower 20 via the boiler 18 and the preduster 19.

Furthermore, the introduction duct 21 for each circulating suction gas
A perforated plate 22 is provided between a portion corresponding to the first suction gas system 7 and a portion corresponding to the second suction gas system 9. A high desulfurization rate can be secured while maximizing the pressure. As a method for securing a high desulfurization rate, ducts from three to five suction boxes near the perforated plate 22 are overlapped with two systems of a first suction gas system 7 and a second suction gas system 9. A high desulfurization rate can also be secured by connecting.

FIG. 2 shows a suction box No. in the length direction of the strand of the sintering machine. It is a figure which shows the relationship between the density | concentration of SOx in the exhaust gas from every 1-32, and the sulfur concentration in a charge.

From the figure, the pattern of the concentration of SOx in the gas discharged from each suction box is not always the same.
It can be seen that it differs depending on the content of S in the charge. That is, as the amount of S in the charged ore increases, the rising region Xa containing SOx (see FIG. 3) moves forward, and the maximum concentration also shows an increasing tendency in accordance with the amount of S in the charged material. It can be seen that is hardly changed at the high concentration SOx level.

The present invention quantitatively grasps the concentration of SOx in the exhaust gas from each suction box, which varies depending on the amount of S in the charge, and uses this for setting the capacity and controlling the operation of the desulfurization apparatus. And increase the desulfurization efficiency.

FIG. 3 is a diagram in which a change in the concentration of SOx in each suction box by the actual machine shown in FIG. 2 is patterned for control.

As shown in FIG. 3, in the operation of the sintering machine in the state shown in FIG. 2, the suction box No. whose SOx content is so small that desulfurization is unnecessary. Regions 1 to 12 are set as region A. This region is also a region where the amount accumulated in the raw material layer is determined by the SOx partial pressure governed by the sum of SOx in the circulating gas and SOx generated by combustion. Further, SO is determined by the content of S contained in the suction gas and S contained in the charge.
An area where the density of x changes is set as a B area. This area is also an area where the discharged SOx rises with the decrease of the charge that can contain S. Further, due to the temperature rise in the raw material layer, the area where S is not accumulated in the raw material layer and the entire amount is discharged is defined as C.
Set the area.

When this method was applied to actual equipment, the total desulfurization rate was about 85% in the conventional operation method under the condition that the S ratio in the compounded raw material was 0.03%. And the total desulfurization rate could be increased to 93%.

[0024]

According to the present invention, the following effects can be obtained.

(1) By formulating the SOx generation pattern according to the amount of S in the charge, a low airflow and high concentration SOx can be taken out and a high desulfurization rate can be secured.

(2) Since the SOx generation pattern and its concentration can be accurately estimated, it is possible to estimate the performance of an appropriate desulfurization device.

(3) Since the SOx concentration of each suction box can be accurately estimated, it is possible to take an acid corrosion prevention measure suitable for each part of the exhaust gas treatment equipment.

[Brief description of the drawings]

FIG. 1 shows an example of an apparatus for performing the method of the present invention.

FIG. 2 shows the concentration of SOx in the exhaust gas from each suction box of the sintering machine in relation to the sulfur content in the charge.

FIG. 3 shows a diagram in which a change in SOx concentration shown in FIG. 2 is patterned for control.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Preheating furnace 2 Ignition furnace 3 First half suction gas system 4 Suction box 5 Heat storage furnace 6 First half area of intermediate bed 7 First suction gas system 8 Rear area of intermediate bed 9 Second suction gas system 10 Late part of bed 11 Third suction gas system 12 Preduster 13 Supply ore side circulation blower 14 Electric precipitator 15 Main exhaust fan 16 Chimney 17 Desulfurizer 18 Boiler 19 Preduster 20 Rear half circulation blower 21 Introductory duct 22 Perforated plate

Continuation of the front page (72) Inventor Masatoshi Miyawaki 1-1, Hibata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka Nippon Steel Corporation Yawata Works (58) Field surveyed (Int. Cl. ⁷ , DB name) B01D 53/30 B01D 53/50 F27B 21/08

Claims (1)

(57) [Claims] An exhaust system from the first half of a bed of a sintering machine is discharged or circulated without passing through a desulfurization device. A system that discharges without going through desulfurization
In the exhaust gas treatment method of a sintering machine divided into three systems, a system that discharges through a desulfurization device in the latter half of the middle part and a system that circulates exhaust gas from the latter half of the bed immediately after ignition to the middle part of the strand , The sum of S and S in the gas sucked into the bed
For each suction box corresponding to the bed charge S represented
After the middle of the bed according to the change in the SOx content pattern
A system that discharges exhaust gas from the half area without passing through the desulfurization device in the first half of the middle part,
Corresponds to the system that discharges through the desulfurization device in the latter half of the area
Perforated partition in the main duct under the bed
A plate is provided to adjust the porosity, or a suction system is introduced from the suction box to the non-desulfurization system and the desulfurization system.
Overlap the range of 30-50% of the suction box from the first half
And switch and adjust according to the SOx generation pattern
Exhaust gas treatment method of the sintering machine, characterized in that.