JPS6125077B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to a waste heat recovery device in a sintering facility, and includes two evaporation sections of a waste heat boiler to recover cooler waste heat and sintering machine waste heat. The waste heat of the cooling equipment is completely recovered, and a small dust collector equipped with a secondary air extraction chamber is also used to efficiently collect dust, reducing the amount of dust contained in the exhaust gas led to the post-treatment process. The purpose of the present invention is to provide a waste heat recovery equipment capable of reducing the rate and keeping the production of steam amount constant.

Sintered ore, which is obtained by sintering fine ore, has been widely used as a raw material for iron manufacturing. And in the sintering equipment,
Since a large amount of high-temperature exhaust gas is discharged, waste heat has been recovered from the exhaust gas, and various recovery methods have been proposed.

However, conventional recovery methods mainly recover waste heat from coolers, and sintering machine waste heat has not been recovered very much, and even when recovery methods are attempted, the equipment is extremely complex. It's summery.

This is because the sintering machine exhaust gas contains SOx, and if the temperature of the treated gas falls below the acid dew point temperature due to heat recovery, the problem of acid corrosion of the equipment will occur.

In addition, a dust collector is required to remove dust from the handled exhaust gas and reduce the dust concentration, but simply installing a dust collector is not enough to increase the dust collection efficiency without requiring a large and expensive dust collector. Another drawback was that it required the use of a 300-millimeter, making the entire device relatively expensive.

The present invention has been made in view of the above, and will be described below with reference to embodiments shown in the drawings.

1 is a sintering machine, 2 is a crusher, and 3 is a cooler. The sintering machine 1 has a pallet that is fixed to a conveyor wrapped around a sprocket 8 and rotates endlessly inside the machine, and the pallet is supplied with sintering raw material from a raw material hopper and is then supplied onto the pallet. The surface layer of the raw material is ignited at a predetermined position, and the pallet is sintered as the pallet advances.

The crusher 2 serves to crush the sintered ore supplied from the sintering machine 1 and supply it to the cooler 3.

The cooler 3 has a structure known per se as the sintering machine 1, and cools the sintered ore as the pallet advances, fixed on a conveyor wrapped around a sprocket 9 and rotated endlessly inside the machine. It's becoming like that. Note that 4 is a product delivery conveyor.

In the sintering machine 1, a large number (approximately 20) of window boxes 5 are provided with openings facing the lower surface of the advancing pallet. The exhaust and intake pipes of each wind box are connected to the main duct 6. A dust collector and a desulfurizer are connected to the main duct 6 via a blower.

The main duct 6 also has a branch pipe 7 that detours only the exhaust gas from the four wind boxes at the final stage of the sintering machine, and the exhaust gas from the final stage of the sintering machine is passed through this branch pipe. The branch pipe 7, which is designed to join the exhaust gas passing through the main duct 6, includes an evaporation section 10 of the waste heat boiler and a secondary air extraction chamber 24.
A dust collector 11 is installed. 1
2, 12', 12'' are switching valves.

In the cooler 3, 13 is a cooler hood, 14
15 is a cooler wind box, 15 is a cooler duct, and 16 is a fan, each of which is provided to target the high-temperature part and low-temperature part of the cooler, that is, to separate and treat the exhaust gas in the front stage and the exhaust gas in the rear stage of the cooler. . The cooler hood 13 and the fan 16 on the high temperature side are connected by a circulation path 19 having an evaporating section 17 of a waste heat boiler and a dust collector 18 having a secondary air extraction chamber 25 inserted therein.

Therefore, the cooling air on the high temperature side flows from the fan 16 to the cooler duct 15 and to each cooler wind box 1.
4. It is exhausted through the sintered ore layer to the cooler hood 13, and from the cooler hood 13, it is circulated through the circulation path 19, through the dust collector 18, and further through the evaporation section 17 of the waste heat boiler. .

Reference numeral 20 is a drum of a waste heat boiler, which communicates with the evaporation sections 10 and 17 provided on the cooler side and the sintering machine, respectively, so as to be used in common.

21 is a water supply conduit to the evaporator section of the waste heat boiler, which is led through the evaporator section 17 to the boiler drum 20.

22 is a hot water conduit, which connects the boiler drum 20
It circulates through the evaporation sections 10 and 17. 2
3 is a steam extraction conduit.

In addition, a secondary air extraction chamber 24 provided in the dust collector 11 on the sintering machine side is connected to the evaporation section 1 through an air extraction duct 26.
The secondary air extraction chamber 25 provided in the dust collector 18 on the cooler side is led to the outlet side of the dust collector 18 and merges with a dust prevention duct (not shown) via a bleed air duct 27 by a blower. It is now released into the atmosphere through a dust collector.

The structure of the present invention is as described above, and its operation will be explained next.

First, the cooler exhaust gas is separated into a high-temperature side and a low-temperature side, and only the high-temperature side exhaust gas waste heat is recovered, so that the evaporator 17 can be supplied with exhaust gas at a temperature of about 300 to 340°C. Hot water is obtained in the boiler drum 20 by supplying water at room temperature (approximately 20° C.) to the low temperature side of the evaporator 17 through the conduit 21.

The hot water in the boiler drum 20 is then sent through the conduit 22 to the high temperature side of the evaporator 17 on the cooler side and the evaporator 10 on the sintering machine side, where it is vaporized by high-temperature waste gas and returned to the boiler drum. Can be stored. At this time, desired high temperature saturated steam can be obtained by adjusting the pressure inside the drum. For example, if the drum internal pressure is set to 9 atmospheres, the temperature will be 174.5°C.

In general, the exhaust gas temperature of a sintering machine becomes high as sintering progresses and sintering is completed, especially the exhaust gas from the final wind box (generally about 3 to 4 from the last in a machine with around 20 wind boxes). reaches around 400℃. At the same time,
The amount of exhaust gas also reaches its maximum in this region.

Therefore, in the present invention, the exhaust gas from the wind box at the final stage of the sintering machine is separated from the exhaust gas from the wind box at the previous stage by simple valve operation (12, 12', 12'') and transferred to a branch pipe. 7, and an evaporator 10 and a dust collector 11 equipped with a secondary air extraction chamber are installed in this branch pipe 7. The hot water supplied from the boiler drum 20 through the conduit 22 is efficiently vaporized and recovered as saturated steam.

At this time, the exhaust gas passing through the branch pipe 7 is transferred to the steam section 10.
Since high-temperature hot water is already supplied to the conduit 22, the exhaust gas flows into the main duct 6 while remaining at a sufficiently high temperature, and joins with the exhaust gas sucked in from the previous stage wind box.

As a result, the entire exhaust gas flowing through the main duct 6 is maintained at a temperature higher than the acid dew point temperature, and SOx contained in the exhaust gas is prevented from being exposed between devices up to the desulfurization device.

In addition, a dust collector 1 equipped with secondary bleed chambers 24 and 25
1 and 18 are provided in the branch pipe 7 and the circulation path 19, respectively, so that even a small dust collector can perform efficient dust collection, and the extracted secondary air is supplied from the outlet side of the evaporator 10. It joins the exhaust gas passing through the main duct 6 through the branch pipe 7. This not only increases the dust collection efficiency, but also reduces the dust concentration in the exhaust gas that is led to a post-treatment process, ie, a blower or the like. The same can be said for the exhaust gas on the cooler side.

[Brief explanation of the drawing]

The drawing is a schematic overall view showing an embodiment of the invention. 5... Wind box, 6... Main duct, 7... Branch pipe, 10... Evaporation section, 11, 18... Dust collector, 1
3... Cooler hood, 14... Cooler wind box, 15... Cooler duct, 17... Evaporation section, 19...
Circulation path, 20...boiler drum, 21...water supply pipe,
22... Hot water conduit, 24, 25... Secondary air extraction chamber.

Claims (1)

[Claims] 1 It has an evaporator section equipped with a dust collector that introduces exhaust gas from the high temperature side of the cooler, and an evaporator section equipped with a dust collector that introduces exhaust gas from the wind box at the final stage of the sintering machine, and both of the evaporator sections A waste heat boiler is constructed by providing a common drum that communicates with the sintering machine, and a secondary air extraction chamber is provided in each of the dust collectors, and a secondary air extraction chamber is provided in the dust collector that introduces the exhaust gas from the wind box at the final stage of the sintering machine. Waste heat recovery equipment for sintering equipment, characterized in that secondary air extracted from a secondary air extraction chamber is made to join exhaust gas passing through a main duct via a branch pipe.