CN111996315A

CN111996315A - Waste heat recovery device for molten slag

Info

Publication number: CN111996315A
Application number: CN202010879181.5A
Authority: CN
Inventors: 况增光; 樊君; 冀中年; 石红勇; 李志伟; 夏腾成; 刘静; 郁建宁
Original assignee: Beris Engineering and Research Corp
Current assignee: Beris Engineering and Research Corp
Priority date: 2020-08-27
Filing date: 2020-08-27
Publication date: 2020-11-27
Anticipated expiration: 2040-08-27
Also published as: CN111996315B

Abstract

The invention provides a waste heat recovery device for molten slag, which comprises: the device comprises an air quenching chamber, a vibrating conveyor, a tailing bin, a waste heat boiler and a booster fan; after being granulated in a wind quenching chamber, the molten slag enters a tailing bin through a vibrating conveyor; the air passes through a booster fan, a tailing bin, a vibrating conveyor, an air quenching chamber and a waste heat boiler in sequence, and in the process, the air and the molten slag reversely run for heat exchange to recover the waste heat of the molten slag. The device can effectively recover the sensible heat of the molten metallurgical slag, and can obtain high-quality metallurgical slag refined particles. The whole device is operated under negative pressure, the efficiency is higher, and the environmental protection performance is better.

Description

Waste heat recovery device for molten slag

Technical Field

The invention relates to the technical field of waste heat recovery in the metallurgical industry, in particular to a waste heat recovery device for molten slag.

Background

At present, in the field of waste heat recovery of pyrometallurgical slag, a large amount of high-temperature molten slag is generated in the production of the pyrometallurgical field, most of the high-temperature molten slag is treated by a water quenching method or a hot stewing method at present, and the defect is that the sensible heat of the molten slag cannot be recycled. With the change of the economic development mode of China from resource consumption type to environment-friendly type, the effective treatment and utilization of the solid wastes are important subjects for the research of metallurgical workers. The slag tapping temperature of pyrometallurgy is about 1600 ℃. About 2000X 10 per ton of slag³Sensible heat in kJ. The sensible heat recovery of the metallurgical slag can reduce energy consumption and environmental pollution at the same time.

The existing slag sensible heat recovery technology is not mature enough, the investment and the application are few, the slag treatment by adopting a water quenching method still occupies a large proportion, the slag flushing water waste heat is only used for heating in winter in part of northern areas, and the utilization rate is very low. The existing molten slag waste heat recovery technology mainly comprises a cup rotating method, a roller method, an air quenching method, a pot type hot stewing method and the like, and mainly has the problems of low heat recovery efficiency, complex equipment, high energy consumption of recovery equipment and the like.

In the existing revolving cup method technology, continuous liquid slag flows into a rotary airflow granulator located in the center through a slag injection pipe, the liquid slag is thrown out and granulated under the action of centrifugal force at the edge of a revolving cup, and annular air jet flow is introduced around the revolving cup at the same time to promote the crushing of the liquid slag. The slag particles impact the water-cooled wall, rebound to the primary fluidized bed, exchange heat with the fluidized air and the heat exchange pipeline buried in the bed layer, and the hot air enters the waste heat recovery system for utilization. As above, the rotary cup method has complicated technical equipment, slag particles are easy to be bonded with a water-cooled wall in the centrifugal granulation process, the recovery efficiency is low, the energy consumption per se is high, and the application effect is poor.

The roller method and the pot-type hot stewing method recover steam by directly contacting slag and water, and the recovered steam has low temperature and high ion content, thereby influencing subsequent use.

Therefore, in view of the shortcomings of the prior art, those skilled in the art will find it desirable to provide a sensible heat recovery technique for metallurgical molten slag that is efficient, low in cost, and meets the quality requirements of tailings.

Disclosure of Invention

In order to solve all or part of the problems, the invention aims to provide a molten slag waste heat recovery device which can effectively recover sensible heat of molten metallurgical slag and achieve the effects of energy conservation and emission reduction.

The invention realizes the above purposes by the following technical scheme:

a molten slag waste heat recovery device, comprising: the device comprises an air quenching chamber, a vibrating conveyor, a tailing bin, a waste heat boiler and a booster fan; after being granulated in a wind quenching chamber, the molten slag enters a tailing bin through a vibrating conveyor; the air passes through a booster fan, a tailing bin, a vibrating conveyor, an air quenching chamber and a waste heat boiler in sequence, and in the process, the air and the molten slag reversely run for heat exchange to recover the waste heat of the molten slag.

Optionally, the vibratory conveyor is a multi-layer vibratory conveyor.

Optionally, the molten slag waste heat recovery device further comprises a slag liquid buffer tank, and the molten slag is guided into the air quenching chamber through the slag liquid buffer tank so as to form a stable slag liquid flow.

Optionally, the molten slag waste heat recovery device further comprises an air compressor and a compressed air spray gun; the compressed air spray gun is arranged on the air quenching chamber, and a gun mouth of the compressed air spray gun faces to a molten slag inlet of the slag liquid buffer tank; the air compressor is connected with the compressed air spray gun, and compressed air generated by the air compressor generates airflow in the air quenching chamber through the compressed air spray gun so as to granulate the molten slag.

Optionally, the molten slag waste heat recovery device further comprises a steam drum and soft water supply equipment; soft water supply equipment to exhaust-heat boiler supplies water, and water is in the heat absorption turns into steam in the exhaust-heat boiler, collects in the steam pocket.

Optionally, the molten slag waste heat recovery device further comprises a vibrating feeder arranged at the bottom of the tailings bin.

Optionally, the molten slag waste heat recovery device further comprises a first capture hood arranged above the slag liquid buffer tank.

Optionally, the molten slag waste heat recovery device further comprises a second capture hood arranged above the vibrating feeder.

Optionally, the molten slag waste heat recovery device further comprises a dust remover, a dust removing fan and a chimney; the smoke and dust collected by the first collecting cover and/or the second collecting cover is dedusted by the deduster and then guided into the chimney by the dedusting fan for emission.

Optionally, the outlet of the booster fan is further connected to the inlet of the dust remover.

According to the technical scheme, the molten slag waste heat recovery device provided by the invention at least has the following advantages:

(1) the molten slag waste heat recovery device provided by the invention can fully recover the sensible heat of the molten slag, and the heat recovery rate can reach more than 70%;

(2) the molten slag waste heat recovery device provided by the invention can obtain high-quality refined metallurgical slag particles, and the finished product slag particle size is less than 5mm and accounts for more than 90%.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

fig. 1 is a schematic structural view of a waste heat recovery device according to embodiment 1 of the present invention;

fig. 2 is a schematic structural view of a waste heat recovery device according to embodiment 2 of the present invention;

FIG. 3 is a schematic structural view of a multilayer vibrating conveyor used in embodiment 1 of the present invention;

description of reference numerals: 1. the device comprises a slag liquid buffer tank, 2, an air compressor, 3, a wind quenching chamber, 4, a compressed air spray gun, 5, a waste heat boiler, 6, a steam drum, 7, a soft water supply facility, 8, a booster fan, 9, a vibration conveyor (9-1, a motor reducer, 9-2, a vibration tank, 9-3, a trough base, 9-4, a vibration buffer), 10, a tailing bin, 11, a vibration feeder, 12, a first collecting cover, 13, a second collecting cover, 14, a dust remover, 15, a dust removing fan, 16 and a chimney.

Fig. 4 depicts a gas circulation process of the waste heat recovery apparatus of embodiment 2.

Detailed Description

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Example 1

As shown in fig. 1, a molten slag waste heat recovery apparatus according to embodiment 1 of the present invention includes: the air quenching chamber 3, the vibrating conveyor 9, the tailing bin 10, the waste heat boiler 5 and the booster fan 8 form a circulation loop. After high-temperature molten slag is granulated in the air quenching chamber 3, the granulated molten slag passes through a vibrating conveyor 9 and finally enters a tailing bin 10; the air passes through a booster fan 8, a tailing bin 10, a vibrating conveyor 9, an air quenching chamber 3 and a waste heat boiler 5 in sequence, and in the process, the air and high-temperature molten slag reversely run and exchange heat to become high-temperature air, and the high-temperature air enters the waste heat boiler to recover waste heat.

The inlet of the vibrating conveyor 9 is connected with the bottom hopper of the air quenching chamber 3, and the heat exchange between the air and the high-temperature molten slag is mainly carried out on the vibrating conveyor 9. In order to improve the heat exchange efficiency between the air and the molten slag, the present embodiment preferably employs a multi-layer vibrating conveyor. As shown in FIG. 3, the multi-deck vibrating conveyor comprises a motor reducer 9-1, a vibrating trough 9-2, a trough base 9-3 and a vibration damper 9-4. The motor reducer 9-1 is arranged at the front end of the inlet of the multilayer vibrating conveyor. The vibration groove 9-2 can be provided with two layers, three layers or more, and the person skilled in the art can select the vibration groove according to the actual application. The trough base 9-3 is arranged below the vibration trough 9-2 and used for supporting the vibration trough 9-2. The lower part of the trough base 9-3 is provided with a vibration buffer 9-4 which is used for buffering and reducing impact and vibration generated in the vibration process, preventing devices from being damaged and ensuring that the molten slag stably runs forwards. The inlet 9-5 of the multi-layer vibrating conveyor faces upwards and is used for receiving the molten slag output by the hopper at the bottom of the air quenching chamber 3. An outlet 9-6 of the multi-layer vibrating conveyor is horizontally arranged and connected with a molten slag inlet of the tailings bin 10, and the molten slag after heat exchange enters the tailings bin 10 through the outlet 9-6. Because the slag particles of the molten slag move forward in the multilayer vibrating conveyor in a layered vibration mode, the heat exchange area is increased, and therefore the heat exchange efficiency is improved. The whole operation time of the high-temperature slag particles from the inlet to the outlet is about 5-10 min, and sensible heat in the molten slag can be fully released. The outer wall of the vibration groove 9-2 is provided with an insulating layer so as to further reduce heat loss.

Besides the horizontal multilayer vibrating conveyor, the vibrating conveyor can be provided with a certain downward angle, the downward angle is not more than 12 degrees in order to prevent the granulated slag from freely rolling off, and the motor power of the vibrating conveyor can be reduced by the certain negative angle.

In order to stably introduce high-temperature molten slag into the air quenching chamber 3, the molten slag waste heat recovery apparatus of the present embodiment is provided with a slag liquid buffer tank 1. The molten slag inlet of the slag liquid buffer tank 1 is arranged on the side wall of the air quenching chamber 3, and the molten slag is guided into the air quenching chamber 3 through the slag liquid buffer tank 1 so as to form a stable slag liquid flow. The slag liquid buffer tank 1 is provided with a heat preservation cover, and the inner wall of the slag liquid buffer tank is built by adopting refractory materials, so that the heat loss of the high-temperature molten slag can be reduced.

In order to sufficiently granulate the molten slag in the air quenching chamber 3, the molten slag waste heat recovery apparatus of the present embodiment is provided with an air compressor 2 and a compressed air lance 4. The compressed air spray gun 4 is arranged on the air quenching chamber 3, and the gun mouth of the compressed air spray gun faces to the molten slag inlet of the slag liquid buffer tank 1. The air compressor 2 is connected with the compressed air spray gun 4 through a pipeline, the compressed air generated by the air compressor 2 generates air flow in the air quenching chamber 3 through the compressed air spray gun 4, and the molten slag liquid is rapidly granulated under the impact of the air flow. For example, in the embodiment, 0.8MPa compressed air is used as a metallurgical molten slag granulation medium, and an airflow impact slag liquid flow of about 200m/s is generated in the air quenching chamber 3 through the compressed air spray gun 4, so that the slag liquid is rapidly crushed and granulated, the finished slag particle size is less than 5mm and accounts for more than 90%, the quality of the finished slag is not affected, and the subsequent pot stewing treatment can be adopted. Of course, other pressures of compressed air or other rates of airflow may be used in this embodiment, as may be appropriate by one skilled in the art.

The air quenching chamber 3 is communicated with a waste heat boiler 5 through a top heat preservation flue. The air and the high-temperature molten slag are converted into high-temperature air at about 1000 ℃ after reverse heat exchange, and the high-temperature air enters the waste heat boiler 5 from the air quenching chamber 3 through the heat preservation flue. The soft water supply equipment supplies water to the waste heat boiler 5, high-temperature air is contacted with the water to convert heat into saturated steam, and the saturated steam is guided into the steam drum 6 from the waste heat boiler 5 through a pipeline and is collected. Meanwhile, the temperature of the air is reduced, and the air enters the next reverse heat exchange cycle. Therefore, the sensible heat of the molten slag is fully recovered, and the heat recovery rate can reach more than 70%.

The residual temperature of the molten slag after sensible heat recovery is about 350 ℃, so that subsequent treatment is facilitated, about 15% of sensible heat in the tailings can be remained, the heat entering the system accounts for about 85% of the total sensible heat of the slag, about 2% of the heat is taken away by 10% of air entering the dust removal, and the heat loss in the recovery process of the system is not more than 15%. The heat recovery rate of the system can reach: 85% × (1-2%) × (1-15%) 71%

The molten slag with the sensible heat recovered enters the tailings bin 10, the tailings bin 10 serves as molten slag storage and transfer equipment, and the system sealing effect can be achieved through the slag particles at the bottom of the bin. The bottom of the tailings bin 10 is provided with a vibrating feeder 11, and the molten slag in the tailings bin 10 is transported and output by the aid of the vibrating feeder 11.

Example 2

As shown in fig. 2, the molten slag waste heat recovery apparatus according to embodiment 2 of the present invention is different from embodiment 1 in that:

also included are devices for collecting and processing soot. During the process of molten slag conveying and heat exchange treatment, dust-doped flue gas is inevitably generated, and if the molten slag is not treated, serious atmospheric pollution is caused, and meanwhile, harm is caused to the health of constructors, so that smoke dust treatment equipment is required to be arranged.

Specifically, the molten slag waste heat recovery device of the present embodiment further includes a first capture hood 12, a second capture hood 13, a dust remover 14, a dust removal fan 15, and a chimney 16.

The first collecting cover 12 is arranged above the slag liquid buffer tank 1, and the second collecting cover 13 is arranged above the vibrating feeder 11 and is used for collecting smoke dust generated in the process of conveying and heat exchange treatment of the molten slag. The smoke is conveyed to a dust collector 14 through a pipeline, subjected to dust removal through the dust collector 14, and then introduced into a chimney 16 by a dust removal fan 15 for emission.

In the embodiment, the outlet of the booster fan 8 is respectively connected with the dust remover 14 and the tailings bin 10 through pipelines. As shown in fig. 4, the air volume of the exhaust-heat boiler 5 is divided into two parts by the booster fan 8, wherein 90% of the air volume passes through the tailings bin 10 and the vibrating conveyor 9, is mixed with 5% of outside air and 5% of compressed air in the air quenching chamber 3, and is returned to the exhaust-heat boiler 5 for recycling heat exchange, so that the heat loss is reduced; after 10% of air volume is mixed with environmental dust removal, the mixture is introduced into a dust remover 14 so as to balance the air volume entering the system from the air quenching facility and ensure the negative pressure operation of the whole system.

Of course, the air volume returned to the circulating heat exchange system can also adopt other proportions, and the selection can be carried out by the technical personnel according to the actual situation.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention, and they should be construed as being included in the following claims and description. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. It is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A molten slag waste heat recovery device is characterized by comprising: the device comprises an air quenching chamber, a vibrating conveyor, a tailing bin, a waste heat boiler and a booster fan; after being granulated in a wind quenching chamber, the molten slag enters a tailing bin through a vibrating conveyor; the air passes through a booster fan, a tailing bin, a vibrating conveyor, an air quenching chamber and a waste heat boiler in sequence, and in the process, the air and the molten slag reversely run for heat exchange to recover the waste heat of the molten slag.

2. The molten slag waste heat recovery device of claim 1, wherein the vibratory conveyor is a multi-layered vibratory conveyor.

3. The molten slag waste heat recovery device of claim 1, further comprising a slag buffer trough through which the molten slag is introduced into the air quenching chamber so as to form a stable slag liquid stream.

4. The molten slag waste heat recovery device of claim 3, further comprising an air compressor and a compressed air lance; the compressed air spray gun is arranged on the air quenching chamber, and a gun mouth of the compressed air spray gun faces to a molten slag inlet of the slag liquid buffer tank; the air compressor is connected with the compressed air spray gun, and compressed air generated by the air compressor generates airflow in the air quenching chamber through the compressed air spray gun so as to granulate the molten slag.

5. A molten slag waste heat recovery device in accordance with claim 1, further comprising a steam drum and a soft water supply; soft water supply equipment to exhaust-heat boiler supplies water, and water is in the heat absorption turns into steam in the exhaust-heat boiler, collects in the steam pocket.

6. The molten slag waste heat recovery device of claim 1, further comprising a vibratory feeder disposed at a bottom of the tailings bin.

7. The molten slag waste heat recovery device of claim 3, further comprising a first capture hood disposed above the slag liquid buffer tank.

8. The molten slag waste heat recovery device of claim 6, further comprising a second capture hood disposed above the vibratory feeder.

9. The molten slag waste heat recovery device of claim 7 or 8, further comprising a dust collector, a dust removal fan and a chimney; the smoke and dust collected by the first collecting cover and/or the second collecting cover is dedusted by the deduster and then guided into the chimney by the dedusting fan for emission.

10. The molten slag waste heat recovery device of claim 9, wherein the outlet of the booster fan is further connected to the inlet of the dust collector.