JPS5870826A - Method and apparatus for recovering heat by preparing particulate slag from molten slag - Google Patents

Abstract

PURPOSE:To carry out heat recovery in high efficiency, in preparing particulate slag, by adjusting the variation of the high temp. gas amount in a primary cooling gas recirculation system by the high temp. gas amount of a secondary cooling gas recirculation system. CONSTITUTION:In continuously preparing highly vitrified particulate slag having no fluffy slag mixed therein from molten slag intermittently flowed down from a supply trough 11, a high temp. gas obtained by heat exchange between a primary cooling gas and finely divided slag is supplied to a slag heat recovery boiler 4 but the variation of a high temp. gas amount in a primary cooling gas recirculation system is compensated by adjusting the high temp. gas amount in a secondary cooling gas recirculation system and the regular operation of the boiler is enabled to carry out heat recovery in high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for continuously producing high-quality granular slag from bath molten slag continuously discharged from various mining furnaces, such as blast furnaces, by VCM every time the iron is tapped, and at the same time with high thermal efficiency. The present invention relates to a method and equipment for recovering slag heat.

Approximately 300 hours of molten slag, commonly called slag, is discharged from the blast furnace for every 1000 tons of hot metal. This molten slab has a high temperature of about 1500° C., and is subjected to water crushing technology or wind crushing technique to produce granular slag gold.

The above-mentioned water pulverization technique is to obtain granular slag with a particle size of 1 to 1.5 cod by injecting a stream of water into the bath-molten slag.
The retained heat is wastefully dissipated, and additional thermal energy is required to dry and produce products, resulting in a significant increase in raw material costs.

Furthermore, although the vitrification rate of the product slag obtained by water pulverization technology is good due to rapid cooling with water, it is porous and therefore easily absorbs water, making it unsuitable for uses such as fine aggregate.

On the other hand, wind crushing technology is a technology that has been developed in recent years by injecting gas into molten slag to produce finely blown slag. Although it depends on the injection conditions such as the shape and the injection gas flow rate, the generation of i4 slag cannot be avoided. Even under the best conditions, this cotton slag is generated on the order of 0.5 mm, and if it is mixed in granular slag products, it will cause a decline in the quality of the product. In fc wind crushing technology, the energy of the gas from the injection nozzle is mainly consumed in making the molten slag fine (JJ conversion energy) and scattering the fine slag (scattering energy).
Since it does not contribute enough to cooling (cooling energy), the fine slag is slowly cooled through the positive conversion point, and crystallization progresses, resulting in granular slag with a low positive conversion rate. It has the following drawbacks.

Therefore, in the production of granular slag using wind crushing technology, the high temperature gas obtained by heat exchange with the high temperature granular slag can be guided to the mailer to perform mailer operation, which has the advantage of enabling effective recovery of slag heat. However, since the supply of bath melt slag is carried out intermittently as described above, the amount of high temperature gas supplied to the mailer fluctuates, which is often unfavorable for the operation of the mailer.

The present invention has been made in view of the above-mentioned problems of the wind crushing technology for producing granular slag from molten slag that is intermittently discharged from a blast furnace, etc., and solves the above-mentioned problems in the conventional wind crushing technology of this type. It is designed to solve the problem. Therefore, an object of the present invention is to provide a method and equipment for recovering slag heat with high thermal efficiency while continuously producing high-quality granular slag with a high degree of vitrification from intermittently supplied molten slag. .

That is, the gist of the present invention as a method invention is to inject a high-speed fluid into the falling molten slag that is intermittently supplied to a granular slag forming chamber to form granular and flocculent slag.
The fine slag is generated and scattered, and the fine slag is brought into countercurrent contact with the upward flow of the primary cooling gas to form a granular slag fluidized bed while performing primary cooling to make it highly vitrified, and the cotton slag mixed therein is floated and collected. The granular slag from the fluidized bed is temporarily retained and stored in a retention hole, and the high-temperature granule slag is controlled and supplied to the retention conduit/guyori heat exchanger with secondary cooling gas. After secondary cooling is performed by bringing the slag into countercurrent contact, it is continuously discharged as a product slag, and the high temperature gas obtained in the secondary cooling and secondary cooling is used to operate a syslag heat recovery gairer, which performs primary cooling during operation of the mailer. The variation in the amount of high temperature gas obtained in the secondary cooling is compensated for by adjusting the amount of high temperature gas obtained in the secondary cooling, so that there is no load variation in the slag operation. The method lies in recovering slag heat.

In addition, the gist of the present invention as an invention of equipment is that a fine slag generation device consisting of a bath molten slag supply gutter and a high-speed fluid injection nozzle is installed on the side, and a wire mesh for collecting and discharging 44 slags is installed at the high temperature gas outlet. A granular slag forming chamber comprising a conveyor device and a primary cooling gas supply device including a perforated plate having a large number of blowholes at the bottom and supplying primary cooling gas through the blowholes; High-temperature slag retention system that temporarily retains and stores high-temperature slag
A heat exchanger that receives a controlled amount of high-temperature granular slag from the s-reduced slag and brings it into contact with a secondary cooling gas in full countercurrent flow for secondary cooling; a slag heat recovery mailer; a granular slag formation chamber; A primary cooling gas circulation system consisting of a slag heat recovery fan, a blower, and a primary cooling gas control Dan Δ; and a secondary cooling gas circulation system consisting of a heat exchanger, a slag heat recovery gairer, a blower, and a secondary cooling gas control Dan Δ. A facility for producing granular slag from bath-melted slag and recovering slag heat.

The present invention will now be described in detail with reference to an embodiment in which molten slag produced from a blast furnace is handled intermittently as shown in FIG. In other words, the granular slag forming chamber Y shown in the gi diagram is
A pulverized slag generation device consisting of a molten slag supply gutter 11 and a high-speed fluid injection nozzle 12 is provided in the 1111 section, and molten slag is intermittently fed into the formation chamber 1 through the feed gutter 11 as shown in Figure #12. is supplied downstream. When the flowing molten slag is bombarded with high-speed fluid from the injection nozzle 12, the bath molten slag is dispersed into fine particles as shown in FIG. The generated fine slag that is scattered has a sufficiently high retained heat and contains a large portion of granular slag and a small portion of cotton slag. In order to make the resulting granular slag into a product with a high vitrification rate, it must be rapidly cooled to below the glass transition point of 800°C to 900°C. Therefore, a perforated plate 14 having a large number of blowholes 15 is provided in the lower part of the formation chamber 1, primary cooling gas is supplied as an upward flow through the blowholes 15, and granular slag as shown in the figure is placed on the perforated plate 14. A fluidized bed is formed to perform the primary cooling of the generated granular slag and the flotation separation of the cotton slag. Further, a wire mesh conveyor device 13 is provided above the formation chamber to collect and discharge the cotton slag floated and separated.

The entire equipment for granular slag manufacturing and slag heat recovery according to the present invention includes, in addition to the granular slag forming chamber 1, a high-temperature slag retention chamber 41 (Fig. 1), and a moving bed for secondary cooling of the high-temperature granular slag. It is equipped with a type heat exchanger 1 and a boiler east for slag heat recovery. In addition, heat exchange in the present invention! As the I8 vessel, any other type suitable for heat exchange with fine particles, such as the commonly-called moving bed type (FIG. 4), fluidized bed type, kiln type, etc., can be used.

Above the granular slag production room, there is a molten slag supply pipe 11 on the side.
and a fluid (including gas and water) injection nozzle 12 is provided, and the fluid flowing down from the supply gutter 11 has a temperature of about 1
High-velocity gas is injected into the bath-molten slag at 500°C to generate and scatter granular and flocculent slag. In addition, a net conveyor 13 for collecting and discharging cotton slag is installed on the ceiling of the creation chamber 1, and a large number of JJt air ports 15 and discharge ports 16 (Fig. 3) are provided at the bottom to create an upward airflow. A perforated plate 14 is provided, and the hot granulated slag is discharged from the discharge port 16.

The scattered fine slag generated in the formation chamber 1 is primarily cooled at a high vitrification rate by the upward flow of primary cooling gas supplied through the large number of blowholes 15 of the perforated plate plate 14. A granular slag fluidized bed is formed on the dish plate 14, and the mixed cotton slag is floated. A granular slag fluidized bed is formed on the perforated plate 14, and the granular slag is heated to a temperature of about 800'
C is maintained at a high temperature and is discharged to the outside of the production chamber 1 through the discharge port 16. In addition, the floated and separated cotton slag adheres to the wire mesh container (A 13) to form a filter no, and the filter layer collects the scattered ultrafine particle slag, so the spring 1a is not required. The cotton slag and ultrafine particles are also discharged to the outside of the formation chamber 1 by a conveyor 13.

The high-speed gas from the injection nozzle 12 supplied into the formation chamber J and the upward flow passing through the perforated plate 14 - the next cooling gas (approximately 1 degree
50°C) exchanges heat with the free-flowing granular slag and the granular slag to form a 4-temperature body with a temperature of approximately 7400°C.
The slag heat is supplied to the slag heat recovery geyser 1 through the slag.

The temperature of the exhaust gas from the slag heat recovery mailer is approximately 150℃.
The low-temperature gas 9 passes through the reflux 419 and is returned to the formation chamber 1 as primary cooling gas, but this reflux path 19
A ZOLON 7 and a primary cooling gas control damper 8 are disposed in the middle, and the primary cooling gas circulation system A is constituted as a whole.

High-temperature granulated slag retention hole 9: The temperature of the slag discharged from the formation chamber 1 and conveyed by the conveyor 20 is about 800°C.
The purpose is to receive and temporarily retain and store the granular slag of 200 mL, and a cut-out control pulse 5 for controllably cutting out the high-temperature granular slag is provided at the lower part of the retention chamber 2. The high-temperature granulated slag cut out and discharged from this retention hollow 92 is configured to be supplied to, for example, a moving bed heat exchanger l via a conveyor 21.

As shown in FIG. 4, the moving 1IIi type heat exchanger has a perforated plate 30 inside which has a large number of blowholes 31 and granular slag drop ports 32 for creating an upward airflow of secondary cooling gas.
are provided in multiple stages, and the granular slag is dropped from the fluidized bed on each perforated plate 30 through each drop port 32 onto the next perforated plate 30. During this time, the heat exchanger l
The slag is configured to perform secondary cooling of the hot granulated slag within the slag. The secondary cooling gas supplied from the lower part of the heat exchanger a1 flows upward through the jet holes 31 of each perforated plate plate 30, and when the high temperature granulated slag is supplied from the upper part, it flows onto each perforated plate plate 30. A granular slag fluidized bed is formed and heat exchange is performed with this bed. The high-temperature granular slag cooled by the secondary cooling gas in the heat exchange ril is discharged as product slag at a temperature of about 200°C onto the R-product granule slag transport conveyor 23 by controlling the cut-out control pulse roller provided at the bottom. Ru.

Said! A branch flow path 33 having a secondary cooling gas control pipe 49 is provided branching from the reflux path 20 after the lower 7, and is passed through the branch ft path 33 to the heat exchanger stop at a temperature of about 150 ml.
The secondary cooling gas is configured to supply secondary cooling gas at a temperature of about 640°C, and is discharged from the upper exhaust port 34 of the heat exchanger as a high-temperature gas with a temperature of about 640°C through heat exchange with the high-temperature granulated slag. is supplied to the slag heat recovery mailer 1 via a high temperature gas flow path 35.

Said grower 7 branch flow path 33, heat exchange 6 stop high temperature gas flow path 3
5, the mailer 4 and the reflux path 19 constitute a secondary cooling gas circulation system B as a whole.

Therefore, the slag heat recovery mailer 1 is supplied with high-temperature gas distributed by both the secondary cooling gas circulation system A and the secondary cooling gas circulation system B. This is to carry out irritable driving.

By the way, the supply of bath molten slag to the granular slag forming chamber 1 is not carried out continuously, but as shown in FIG. Since this is carried out intermittently in a wavy manner, the amount of high-temperature gas obtained in the secondary cooling gas circulation system A fluctuates, and operation of the mailer solely based on this will cause load fluctuations, which is extremely difficult for the I-Ira operation. It's inconvenient. However, according to the equipment of the present invention, the high-temperature gas obtained in the secondary cooling gas circulation system B can be supplied to the male slag, and the electricity of the high-temperature gas is absorbed by the high-temperature slag stagnant water.

The above-mentioned secondary cooling gas circulation is used to control the amount of high-temperature granular slag cut out and supplied from the nozzle 1 to the $ dynamic no-type heat exchanger a3, and also to control the amount of secondary cooling gas supplied to the heat exchanger 4. The amount can be set as necessary and sufficient to compensate for fluctuations in the amount of high temperature gas supplied in the system A.

Therefore, the slag heat recovery mailer 1 can be operated continuously without any load fluctuation.

As is clear from the above description, according to the method and equipment of the present invention, it is possible to continuously produce high-quality granular slag that is highly vitreous and does not contain cotton slag from intermittently supplied bath-melted slag. At the same time, the high-temperature gas obtained by heat exchange between the primary cooling gas and the finely divided slag, and the high-temperature gas obtained by heat exchange between the secondary cooling gas and the high-temperature granulated slag, are supplied to the slag heat recovery mailer for ♂ irra operation. A steady I
This enables irritating operation and achieves highly efficient heat recovery.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the entire equipment for recovering slag heat while producing granular slag according to the method of the present invention, Fig. 2 is a time chart showing fluctuations in the amount of bath melt slag supplied, and Fig. 3 is a granular slag production method. An enlarged schematic explanatory diagram of the slag forming chamber. Figure 4 is a vertical cross-sectional view showing the granular slag fluidized bed on the perforated plate in the heat exchanger. Hopper, l... moving bed heat exchanger, earth... slag heat recovery ♂ira, 5... control pulp for cutting out high temperature granular slag, 6... control pulp for cutting out product granule slag, 7...・Flotsu, 8...-Secondary cooling gas 1elJ godanno 4゜9...Secondary cooling gas control Dan 14 Net conveyor for embroidery slurry discharge, 14...
Arc plate, 15... Fumarole port, 16... Grain slag door outlet, 17... Exhaust port, 18... High temperature gas flow path, Engineering 9... Return path, 20.21... High-temperature grain slag conveyor 422... Product grain slag conveyor, 30... Perforated plate, 31... Fumarole,
32... Grain slag falling port, 33... Branch flow path, 34
...Exhaust port, 35...High temperature gas flow path. Fig. 1 f -Heguchi 1 I-

Claims (1)

[Claims] 1. A high-speed fluid is injected into the falling bath molten slag that is intermittently supplied to the granular slag forming chamber to generate and scatter granular and flocculent fine slag, and the fine slag is A granular slag fluidized bed is formed while the upward flow of the cooling gas is brought into countercurrent contact with the granular slag to form a granular slag fluidized bed while performing primary cooling to obtain a high I lath quality, and the mixed cotton slag is floated and collected and discharged to the outside of the granular slag forming chamber. , the granular slag from the fluidized bed is temporarily retained and stored in a retention hopper, and the secondary cooling gas is brought into countercurrent contact with the high temperature granular slag that is controlled and supplied from the retention hopper to the moving bed heat exchanger. After performing secondary cooling, the product is continuously discharged as slag, and the high temperature gas obtained in the secondary cooling and secondary cooling is used to operate a slag heat recovery boiler, and during one turn of the boiler, it is immersed in primary cooling. A process for manufacturing granular slag from bath-melted slag, characterized in that fluctuations in the amount of high-temperature gas are compensated for by adjusting the amount of high-temperature gas obtained in secondary cooling, so that there are no load fluctuations in the blower operation. How to recover heat. 2. A fine slag generation device consisting of a bath melt slag supply gutter and a high-speed fluid injection nozzle is installed on the side, a wire mesh conveyor device for collecting and discharging cotton slag is installed at the high temperature gas outlet, and an eye with a large number of blowholes is installed at the bottom. A granular slag forming chamber including a plate plate and each provided with a primary cooling gas supply device that supplies primary cooling gas through the nozzle; a high-temperature slag for temporarily retaining and storing high-temperature granular slag discharged from the granular slag forming chamber; Slag Retention Hota: A heat exchanger that receives a controlled amount of high-temperature granulated slag from a retention hole and brings it into countercurrent contact with secondary cooling gas to perform secondary cooling; slag heat Recovery boiler; granular slag production room, slag heat recovery boiler,! A primary cooling gas circulation system consisting of a heat exchanger, a slag heat recovery boiler, a heat exchanger, a slag heat recovery boiler, a secondary cooling gas circulation system consisting of a heat exchanger, a slag heat recovery boiler, and a secondary cooling gas control system t4. Equipment that recovers slag heat while producing granular slag from bath-melted slag.