CN111578725B

CN111578725B - Device for rapidly cooling and treating dioxin for electric arc furnace and application thereof

Info

Publication number: CN111578725B
Application number: CN202010436265.1A
Authority: CN
Inventors: 杨凌志; 陈凤; 郑富强; 胡航; 郭宇峰; 王帅; 姜涛; 李光辉; 李骞; 王超; 刘阔; 薛波涛
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2020-05-21
Filing date: 2020-05-21
Publication date: 2021-05-07
Anticipated expiration: 2040-05-21
Also published as: CN111578725A

Abstract

The invention discloses a device for rapidly cooling and treating dioxin for an electric arc furnace and application thereof, wherein the device comprises a waste heat recovery section and a flue gas rapid dry cooling section; the waste heat recovery section comprises a heat conduction oil circulation loop and an absorption heat pump unit; the flue gas rapid dry cooling section comprises a semiconductor refrigeration module arranged on a flue of the electric arc furnace, the semiconductor refrigeration module comprises a cold end, a hot end and a dividing wall type heat exchanger, and the cold end is in contact with flue gas in the flue of the electric arc furnace for heat exchange; the evaporator refrigerant outlet is communicated with the semiconductor refrigeration module refrigerant input pipeline, the absorber refrigerant inlet is communicated with the semiconductor refrigeration module refrigerant output pipeline, and the hot end of the semiconductor refrigeration module exchanges heat with the refrigerant in the pipeline through the dividing wall type heat exchanger. The invention lowers the temperature of the flue gas by stages, quickly crosses a large amount of dioxin generation temperature range of 200-400 ℃, and does not change the relative humidity of the flue gas, so that the flue gas can adapt to the humidity requirement of a high-temperature bag-type dust collector.

Description

Device for rapidly cooling and treating dioxin for electric arc furnace and application thereof

Technical Field

The invention relates to a flue gas treatment device for an electric arc furnace, in particular to a device for rapidly cooling and treating dioxin for the electric arc furnace and application thereof.

Background

As one of short-flow steelmaking methods, electric arc furnace steelmaking has the advantages of flexible control of temperature, high thermal efficiency, controllable atmosphere in the furnace, simple equipment, short process flow and the like, and is rapidly developed at home and abroad. The electric arc furnace steel making belongs to high temperature occasions, a large amount of high temperature flue gas can be generated in the smelting process, the temperature of the high temperature flue gas reaches 1200 ℃, and the high heat recovery value is achieved. The scrap steel preheating technology in recent years greatly utilizes the heat of the high-temperature flue gas, saves energy, achieves a relatively ideal preheating effect, and also brings problems. The scrap steel for electric arc furnace steelmaking has wide sources and various varieties, is not effectively integrated and classified, often contains a large amount of organic compounds and chlorides, and can generate a large amount of dioxin under the action of high-temperature flue gas. Dioxin is high in toxicity and can be suspended in air, so that the human body can be greatly damaged, and the environment is seriously polluted, so that the problems of emission reduction and treatment of the dioxin in the steelmaking process of the electric arc furnace are particularly urgent.

The commonly used method for treating dioxin generated in the steelmaking process of the electric arc furnace at present comprises the following steps: in the flue gas treatment, secondary combustion treatment of flue gas after waste steel preheating, quenching treatment by adopting water spray cooling and the like are carried out; controlling at a source, such as classification treatment of scrap steel before entering a furnace, slow feeding operation, addition of a proper amount of alkaline adsorbent and the like; and performing treatment at the tail end, such as high-efficiency filtration technology, physical adsorption technology, catalytic decomposition technology and the like. The technology can reduce the content of dioxin in the steelmaking process of the electric arc furnace to a certain extent in the using process, but has some defects. The adsorption area of the active carbon is too small, and secondary dust can be generated by spraying carbon powder; the secondary combustion of the flue gas can consume redundant energy, the water spray quenching can cause the steam content in the discharged flue gas to be too high, the corrosion to equipment is large, the subsequent bag-type dust removal cannot be used, and only the electric dust removal with lower use effect can be carried out.

Disclosure of Invention

Aiming at the defects of the existing quenching technology for processing the dioxin in the steelmaking process of the electric arc furnace, the invention provides a device for quenching and treating the dioxin for the electric arc furnace and application thereof, and the content of the dioxin in the discharged flue gas is effectively reduced.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a device for rapidly cooling and treating dioxin for an electric arc furnace comprises a waste heat recovery section and a flue gas rapid dry cooling section;

the waste heat recovery section comprises a heat conduction oil circulation loop and an absorption heat pump unit, and the absorption heat pump unit comprises a generator, an absorber, a condenser and an evaporator; the heat conduction oil circulation loop is used for enabling heat conduction oil to exchange heat with high-temperature flue gas in a flue of the electric arc furnace and then transmitting the heat of the heat conduction oil to a generator of the absorption heat pump unit;

the flue gas rapid dry cooling section comprises a semiconductor refrigeration module arranged on a flue of the electric arc furnace, the semiconductor refrigeration module comprises a cold end, a hot end and a dividing wall type heat exchanger, and the cold end is in contact with flue gas in the flue of the electric arc furnace for heat exchange;

the evaporator refrigerant outlet is communicated with the semiconductor refrigeration module refrigerant input pipeline, the absorber refrigerant inlet is communicated with the semiconductor refrigeration module refrigerant output pipeline, and the hot end of the semiconductor refrigeration module exchanges heat with the refrigerant in the pipeline through the dividing wall type heat exchanger.

Furthermore, a wall attachment effect air inducing device is arranged on an electric arc furnace flue between the waste heat recovery section and the flue gas rapid dry cooling section, and comprises a high-speed airflow air outlet part and a compressed air output pipeline;

the high-speed airflow air outlet part is formed by enclosing an outer ring of the high-speed airflow air outlet and an inner ring of the high-speed airflow air outlet, the cross section of the high-speed airflow air outlet part is in a hollow annular shape, one side of the high-speed airflow air outlet part, which is opposite to the incoming flow direction of the flue gas, is sealed, and the other side of the high-speed airflow;

the compressed air output pipeline is communicated with the high-speed airflow air outlet part; the compressed air output pipeline is communicated with the low-temperature air circulation pipeline, and a fan is arranged between the compressed air output pipeline and the low-temperature air circulation pipeline; the low-temperature air circulation pipeline is connected with a low-temperature air outlet of the evaporator and is used for conveying low-temperature air cooled by the evaporator;

the air flow in the low-temperature air circulation pipeline is pressurized by the fan, then enters the high-speed air flow air outlet part through the compressed air output pipeline, flows out from the high-speed air flow annular air outlet, is mixed with the flue gas in the flue of the electric arc furnace, and then enters the flue gas rapid drying and cooling section.

Furthermore, the part of the heat conducting oil circulation loop, which is positioned in the flue of the electric arc furnace, is spiral.

Furthermore, the heat conduction oil circulation loop comprises a main loop, a first valve and a heat conduction oil pump are arranged on the main loop, the main loop is divided into a first branch and a second branch, a third valve is arranged on the first branch, a fourth valve and a heat conduction oil pool are arranged on the second branch, the first branch and the second branch are converged into the main loop and are divided into a third branch and a fourth branch, a second valve and an oil storage tank are arranged on the third branch, a fifth valve is arranged on the fourth branch, and the third branch and the fourth branch are converged into the main loop; the heat-conducting oil pool is used as a high-temperature heat source for driving the generator.

Furthermore, a high-temperature heat pipe is arranged in the heat conduction oil pool to transmit the heat of the heat conduction oil to the generator.

Furthermore, the absorption heat pump unit is provided with a lithium bromide solution heat exchanger for preheating the low-temperature lithium bromide dilute solution from the absorber by the high-temperature lithium bromide concentrated solution output by the generator.

Furthermore, the section of the semiconductor refrigeration module is annular and is arranged between the two sections of the flue of the electric arc furnace.

Furthermore, the semiconductor refrigeration module adopts a plurality of semiconductor refrigeration modules which are combined in series.

Furthermore, the flue gas rapid drying and cooling section is connected with the cloth bag dust removal section.

The application of the device in the treatment of dioxin is as follows:

(1) in the initial stage of the electric arc furnace smelting, the first valve and the third valve are both opened, the fourth valve is closed, the second valve or the fifth valve is opened or both are opened, the absorption heat pump unit is not opened, and the semiconductor refrigeration module is opened;

(2) in the middle stage of smelting in the electric arc furnace, the first valve and the fourth valve are both opened, the second valve or the fifth valve is opened, the third valve is closed, the heat conduction oil pump is opened, and the absorption heat pump unit and the semiconductor refrigeration module are simultaneously opened;

(3) and at the last stage of the electric arc furnace smelting, the first valve and the fourth valve are opened, the second valve or the fifth valve is opened, the third valve is closed, the heat conduction oil pump is opened, the absorption heat pump unit is opened, and the semiconductor refrigeration module is opened or closed according to the smoke temperature.

The invention provides a device combining heat pump heat recovery and semiconductor quenching, which can quickly cool flue gas after preheating scrap steel to below 200 ℃ through dry cooling to prevent generation of dioxin, thereby reducing the content of dioxin in discharged flue gas. Through the connection of the waste heat recovery section, the flue gas quenching section and the bag-type dust removal section, the temperature of the flue gas is reduced in stages, and the temperature range of large-amount generation of dioxin at 200-400 ℃ is quickly spanned, and meanwhile, the relative humidity of the flue gas is not changed, so that the flue gas can adapt to the humidity requirement of a high-temperature bag-type dust remover.

Compared with the prior art, the invention has the beneficial effects that:

(1) the flue gas temperature in the electric arc furnace steelmaking process is reduced through quenching, the relative humidity of the flue gas is not changed while the flue gas temperature is lower than the generation temperature of dioxin, external moisture is not introduced, the high-efficiency ventilation dedusting method which has strict requirements on moisture content such as subsequent bag-type dedusting is convenient, the concentration and the content of other harmful substances such as dioxin in the flue gas in the electric arc furnace steelmaking process can be greatly reduced, a plurality of problems of bag-type dedusting application in the electric arc furnace steelmaking process in the current stage are solved, and the environment is protected.

(2) The double-effect refrigeration method of coupling the absorption heat pump unit refrigeration and the semiconductor refrigeration can realize quick refrigeration input and quick cooling, realize dry cooling of flue gas in the steelmaking process of an electric arc furnace, solve the defects of water spray cooling commonly adopted in the current practical process, and effectively solve various problems that the semiconductor refrigeration efficiency is low and heat cannot be dissipated in time by using the refrigerant with lower temperature of the absorption heat pump unit to quickly cool the hot end of the semiconductor refrigeration module.

(3) The application of the wall attachment effect air inducing device can solve the problem of overlarge resistance in the bag dust removing process of subsequent flue gas treatment in the dry cooling process, can also strengthen the mutual mixing and heat exchange process of hot flue gas and cold air, achieves the effect of rapid cooling, and simultaneously solves the problems that a common induced draft fan in a flue is easy to adhere dust and is difficult to clean and the like.

(4) The control is convenient, the cold quantity supply can be changed along with the changeable flue gas volume and temperature in the steelmaking process of the electric arc furnace, the refrigeration control is convenient to carry out, and the cold quantity supply can be effectively coupled with an intelligent control system for the steelmaking of the electric arc furnace in the follow-up improvement and development.

(5) The whole system is driven by the waste heat of the flue gas in the steelmaking process of the electric arc furnace, the external input energy is only components which need power consumption, such as a solution pump for driving the absorption heat pump unit, a heat conduction oil pump in a heat conduction oil circulation loop and the like, and the power consumption of the components is very little relative to the benefit obtained by the whole device, so that the device has advantages and prospects in the aspects of energy conservation, environmental protection, emission reduction, harm removal and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an apparatus for quenching treatment of dioxin in an electric arc furnace according to an embodiment of the present invention;

FIG. 2 is a perspective view of the coanda effect wind-inducing apparatus;

FIG. 3 is a front view of the coanda effect draft gear;

FIG. 4 is a side view of the coanda effect wind inducing device;

FIG. 5 is a cross-sectional view A-A of FIG. 1;

FIG. 6 is a schematic illustration of semiconductor refrigeration (cross-sectional view B-B in FIG. 5);

fig. 7 is a schematic diagram of a plurality of semiconductors in series for refrigeration.

Wherein: 1. a waste heat recovery section; 2. a flue gas rapid drying and cooling section; 3. a bag dust removal section; 4. an electric arc furnace flue; 5. a first valve; 6. a heat-conducting oil pump; 7. an outlet of the spiral heat conducting oil heated pipeline; 8. a spiral heat conducting oil heating pipeline; 9. the inlet of the spiral heat conducting oil heating pipeline; 10. an oil storage tank; 11. a second valve; 12. a third valve; 13. a fourth valve; 14. a heat transfer oil sump inlet; 15. a high temperature heat pipe; 16. a generator lithium bromide dilute solution inlet; 17. a lithium bromide solution heat exchanger; 18. a lithium bromide solution circulating pump; 19. an absorber lithium bromide dilute solution outlet; 20. a first live hot water pipeline; 21. a first domestic hot water tank; 22. a heat conducting oil pool; 23. an outlet of the heat-conducting oil pool; 24. a second domestic hot water tank; 25. a second domestic hot water pipe; 26. a pressure reducing valve; 27. a generator lithium bromide concentrated solution outlet; 28. a generator; 29. a generator refrigerant outlet; 30. a condenser refrigerant inlet; 31. a condenser; 32. a condenser refrigerant outlet; 33. an absorber lithium bromide concentrated solution inlet; 34. an absorber; 35. an absorber refrigerant inlet; 36. an evaporator refrigerant outlet; 37. an evaporator; 38. a throttle valve; 39. an evaporator refrigerant inlet; 40. an evaporator low temperature air outlet; 41. the air suction side of the wall attachment effect air inducing device; 42. a coanda effect air inducing device; 43. a fifth valve; 44. the base is in threaded connection; 45. a low temperature air circulation duct; 46. a semiconductor refrigeration power supply distribution box; 47. a semiconductor refrigeration power supply lead; 48. the air outlet side of the wall attachment effect air inducing device; 49. a semiconductor refrigeration module; 50. a semiconductor refrigeration module refrigerant inlet; 51. a semiconductor refrigeration module refrigerant input pipe; 52. a semiconductor refrigeration module refrigerant outlet; 53. a semiconductor refrigeration module refrigerant output pipeline; 54. a bag-type dust collector; 55. a flue gas outlet duct; 56. a low temperature air flow control switch; 57. a brushless motor; 58. a compressed air output duct; 59. a base; 60. an outer ring of the high-speed airflow air outlet; 61. a high-speed airflow annular air outlet; 62. an inner ring of the high-speed airflow air outlet; 63. a semiconductor element power supply lead; 64. an n-type semiconductor; 65. a cold end metal plate; 66. cold-end heat-conducting ceramic; 67. a p-type semiconductor; 68. a hot end metal plate; 69. a hot-end thermally conductive ceramic; 70. a dividing wall type heat exchanger; 71. a semiconductor refrigeration power supply device; a. flue gas; b. high velocity air flow.

Detailed Description

In order to facilitate understanding of the invention, the invention will be described more fully and in detail with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

As shown in figure 1, the device for rapidly cooling and treating dioxin by the electric arc furnace in the embodiment of the invention mainly comprises a waste heat recovery section 1, a flue gas rapid dry cooling section 2 and a cloth bag dust removal section 3 which are connected in sequence. The device collects the back to the flue gas that comes from electric arc furnace flue and electric arc furnace factory building top exhaust port, through cascaded cooling, lets the temperature of electric arc furnace delay reduce rapidly, strides across the best generation temperature interval of dioxin fast to reduce the content of dioxin.

Dioxin is colorless crystalline solid, is lipophilic and fat-soluble compound, is extremely insoluble in water, acid and alkali, is soluble in most organic solvents, has a high melting point, and has a decomposition temperature generally higher than 700 ℃. Synthesized on the surface of fly ash through a series of elementary reactions under the condition of 250-450 ℃ and in the presence of residual carbon, chlorine source and transition metal. Through the quenching technology, the temperature of the flue gas can be quickly reduced to be below 200 ℃, the flue gas flows out from the flue gas outlet pipeline 55, and the synthesis of dioxin is reduced, so that the emission concentration of dioxin and other harmful solid particles in the final flue gas emission is reduced.

The flue gas of electric arc furnace flue 4 the inside is by the flue gas of electric arc furnace fourth hole the inside and the flue gas that the factory building top smoke vent of electric arc furnace escaped constitute, collects these two strands of flue gases after, concentrates again and carries out waste heat recovery and rapid cooling and handle, and the heat that can be used to retrieve like this is more, and the flue gas volume of handling simultaneously is bigger.

The waste heat recovery section 1 mainly comprises a heat conduction oil circulation loop and an absorption heat pump unit.

The part of the heat conducting oil circulation loop in the flue 4 of the electric arc furnace is spiral. The spiral heat conducting oil heated pipeline 8 is spirally arranged in the electric arc furnace flue 4, heat conducting oil enters the electric arc furnace flue 4 from the spiral heat conducting oil heated pipeline inlet 9, the heat conducting oil flows out of the electric arc furnace flue 4 from the spiral heat conducting oil heated pipeline outlet 7, the heat exchange mode of the internal heat conducting oil and high-temperature flue gas of the electric arc furnace is counter-flow type dividing wall heat exchange, the heat exchange efficiency of the heat exchange mode is higher, and more heat of the flue gas can be absorbed.

The first valve 5, the second valve 11, the third valve 12, the fourth valve 13 and the fifth valve 43 mainly control the flow of the heat transfer oil circulation loop (i.e. the black part fluid shown in fig. 1) and the opening and closing of the related passages. Therefore, the valve is required to be capable of opening and closing and opening control and has certain high-temperature resistance and corrosion resistance.

The heat conducting oil circulation loop in the embodiment comprises a main loop, a first valve 5 and a heat conducting oil pump 6 are arranged on the main loop connected with a spiral heat conducting oil heated pipeline outlet 7, the main loop is divided into a first branch and a second branch, a third valve 12 is arranged on the first branch, a fourth valve 13 and a heat conducting oil pool 22 are arranged on the second branch, then the first branch and the second branch are converged into the main loop and then divided into a third branch and a fourth branch which are respectively controlled by a second valve 11 and a fifth valve 43, an oil storage tank 10 is arranged on the branch controlled by the second valve 11, the main purposes of storing the redundant heat in the links with larger smoke volume and higher temperature in the steelmaking process of an electric arc furnace and simultaneously keeping the heat conducting oil at higher temperature are achieved, and more important purposes of enabling the smoke with higher temperature and larger volume in the middle stage of electric arc furnace smelting to pass through adjusting an oil supply loop, the variable flow regulation of the heat conduction oil can be realized through the two branches controlled by the second valve 11 and the fifth valve 43, the heat carrying capacity of the heat conduction oil is enhanced, and more heat can be provided for the absorption heat pump unit by increasing the flow in unit time.

The oil storage tank 10 stores heat conduction oil inside, and the phase-change heat-insulating material wraps the oil storage tank outside, so that the heat generated when the initial flue gas volume is not large and the temperature is not high can be stored, and meanwhile, the redundant heat can be stored when the flue gas volume is large in the middle stage of electric arc furnace smelting.

The heat conduction oil pump 6 mainly provides power for the circulation of heat conduction oil. Because the heat conduction oil has temperature difference in the circulation loop, so that density difference exists, the pressure difference caused by the density difference can drive the heat conduction oil to move in the loop. Therefore, the acting pressure of the heat transfer oil pump can be relatively smaller, the flow speed of the heat transfer oil is not too fast, and the heat transfer oil needs to be fully exchanged with the flue gas.

The high-temperature heat conduction oil flows into the heat conduction oil pool 22 from the heat conduction oil pool inlet 14 and flows out from the heat conduction oil pool outlet 23, the heat of the heat conduction oil is transmitted to the generator 28 of the lithium bromide absorption heat pump unit through the high-temperature heat pipe 15 inside, and the generator is used as a high-temperature heat source for driving the generator, so that the flue gas waste heat recycling link in the steelmaking process of the electric arc furnace is completed. The high-temperature heat pipe 15 is a high-efficiency heat exchanger, the heat exchange capacity and the heat exchange efficiency are higher than those of various heat exchangers at present, and heat can be quickly and efficiently transmitted to a loop of the absorption heat pump unit from heat conduction oil by using the high-temperature heat pipe.

The absorption heat pump unit mainly comprises a generator 28, a condenser 31, a throttle valve 38, an evaporator 37, an absorber 34, a lithium bromide solution circulating pump 18, a lithium bromide solution heat exchanger 17 and a pressure reducing valve 26. The absorption heat pump unit is used for recovering waste heat of high-temperature flue gas, preliminarily reducing the temperature of the high-temperature flue gas, utilizing the recovered heat as a heat source driven by a heat pump to realize refrigeration, obtaining cold energy capable of enabling the flue gas to be further rapidly cooled, and simultaneously producing domestic hot water. The absorption heat pump unit of the waste heat recovery section has low energy consumption, and simultaneously recovers and utilizes high-temperature waste heat, reduces the temperature of flue gas, and provides conditions for subsequent quenching.

The main function of the lithium bromide solution heat exchanger 17 is to preheat the low-temperature lithium bromide dilute solution from the absorber 34 by using the high-temperature lithium bromide concentrated solution output from the generator 28, so as to improve the operation efficiency and refrigeration efficiency of the lithium bromide absorption heat pump unit.

The lithium bromide solution circulation pump 18 is the main power consuming component in the lithium bromide absorption chiller unit and functions to provide sufficient operating pressure for the circulation of the lithium bromide solution in the lithium bromide solution circulation loop. In the present apparatus, since the lithium bromide solution circulation circuit is short and there is a pressure difference due to a density difference caused by a temperature difference, the pressure head of the lithium bromide solution circulation pump 18 is relatively not so large.

The first domestic hot water pipeline 20, the first domestic hot water tank 21, the second domestic hot water tank 24 and the second domestic hot water pipeline 25 respectively utilize waste heat from the lithium bromide concentrated solution in the absorber 34 and liquefaction heat release of the refrigerant in the condenser 31 to heat cooling water subjected to external partition wall heat exchange, so that domestic hot water for people to use is obtained.

Pressure relief valve 26 functions to depressurize the high pressure lithium bromide concentrate entering absorber 34 to reduce impact and damage to the components, while also facilitating absorption of the refrigerant by the absorber and facilitating the refrigerant cycle.

Both the condenser 31 and the evaporator 37 are recuperative heat exchangers, with the following differences: the refrigerant in the refrigerant pipeline and the cooling water in the cooling water pipeline outside the refrigerant pipeline exchange heat inside the condenser 31, namely, a dividing wall type water-water heat exchanger; the liquid refrigerant in the refrigerant pipeline inside the evaporator 37 exchanges heat with the outside air, so as to reduce the temperature and humidity of the outside air, obtain low-temperature air, enter the low-temperature air circulation pipeline 45 from the evaporator low-temperature air outlet 40, enter the wall attachment effect air inducing device under the pressure increase of the turbine of the fan driven by the brushless motor 57, attract the flue gas and perform forced convection heat exchange with the flue gas, and rapidly reduce the temperature of the flue gas.

The throttle valve 38 is used for throttling and depressurizing the high-pressure normal-temperature liquid refrigerant from the condenser 31, so as to ensure that the refrigerant can absorb heat of air outside the evaporator after entering the evaporator 37, thereby forming gaseous refrigerant and obtaining low-temperature air.

The principle of the absorption heat pump unit is as follows: after the lithium bromide aqueous solution in the generator 28 is heated by the cold end of the heat pipe, the water in the solution is continuously vaporized because the boiling point of the water is far lower than that of the lithium bromide; as the water is continuously vaporized, the concentration of the lithium bromide aqueous solution in the generator 28 continuously increases, flows out from the generator lithium bromide concentrated solution outlet 27, and enters the absorber 34 from the absorber lithium bromide concentrated solution inlet 33; the water vapor enters the condenser 31 through the generator refrigerant outlet 29 and the condenser refrigerant inlet 30, is cooled by cooling water in the condenser 31 and then is condensed to form high-pressure low-temperature liquid water; when water in the condenser 31 enters the evaporator 37 from the condenser refrigerant outlet 32 through the throttle valve 38 and the evaporator refrigerant inlet 39, the water is rapidly expanded and vaporized, and a large amount of heat of refrigerant water in the evaporator 37 is absorbed in the vaporization process, so that the purpose of cooling is achieved, the cold energy is taken away by chilled water flowing through the evaporator 37, the chilled water can be independently used as chilled water for an air conditioning unit of a steel plant or used in a cooling process flow of chilled water required in an electric arc furnace steelmaking flow, in the process, low-temperature water vapor enters the absorber 34 and is absorbed by a lithium bromide aqueous solution in the absorber 34, the solution concentration is gradually reduced, and the low-temperature water vapor is sent back to the generator 28 (through the absorber lithium bromide dilute solution outlet 19 and the generator lithium bromide dilute solution inlet 16) by a circulating pump to complete the whole cycle. The circulation is not stopped, and the cold energy is continuously produced. The evaporator refrigerant outlet 36 communicates with a semiconductor refrigeration module refrigerant input line 51 and the absorber refrigerant inlet 35 communicates with a semiconductor refrigeration module refrigerant output line 53.

Because the dilute lithium bromide solution is cooled in the absorber 34 and the temperature is lower, in order to save the heat for heating the dilute solution and improve the thermal efficiency of the whole device, a lithium bromide solution heat exchanger 17 is added in the system, so that the high-temperature concentrated solution flowing out of the generator 28 and the low-temperature dilute solution flowing out of the absorber 34 exchange heat, and the temperature of the dilute solution entering the generator 28 is improved. Because the boiling point of the lithium bromide aqueous solution is very high (1265 ℃), the lithium bromide aqueous solution is extremely difficult to volatilize, and therefore, the steam on the liquid surface of the lithium bromide saturated solution can be considered as pure water steam; under a certain temperature, the water vapor saturation partial pressure on the liquid surface of the lithium bromide water solution is less than the saturation partial pressure of pure water; and the higher the concentration, the lower the partial pressure of water vapor saturation on the liquid surface. Therefore, under the same temperature condition, the higher the concentration of the lithium bromide aqueous solution is, the stronger the capacity of absorbing moisture is, and the circulation of the process can be ensured.

The low-temperature air circulation pipeline 45 is mainly used for conveying low-temperature air cooled by the evaporator 37 to the inside of the coanda effect air inducing device 42, and then a fan driven by a brushless motor 57 in the low-temperature air circulation pipeline is used for supercharging so as to ensure that the air speed of the high-speed air flow annular air outlet 61 is higher, thereby forming local negative pressure to quickly attract smoke in a flue.

Referring to fig. 2-4, the coanda effect air inducing device 42 is mainly composed of a coanda effect air inducing device air suction side 41, a coanda effect air outlet side 48, a high-speed airflow air outlet outer ring 60, a high-speed airflow annular air outlet 61, a high-speed airflow air outlet inner ring 62, a base threaded connection 44, a base 59, a brushless motor 57, a compressed air output pipeline 58, a low-temperature airflow control switch 56 arranged on the base 59, and other components or structures. The compressed air output pipeline 58 is vertically arranged below the outer ring 60 of the high-speed airflow air outlet and is connected and sealed with an air vent of the outer ring 60 of the high-speed airflow air outlet, and the compressed air output pipeline 58 is communicated with the low-temperature airflow circulating pipeline 45. The main function of the device is to pressurize the low-temperature air from the evaporator 37 of the absorption heat pump unit and provide kinetic energy, so that high-speed airflow with extremely high speed is formed at the annular high-speed airflow outlet 61, thereby forming local negative pressure, sucking the flue gas in the flue of the electric arc furnace, preventing the flue gas from locally staying and covering on a semiconductor refrigerating device to influence the semiconductor refrigerating efficiency, simultaneously, the high-speed airflow also strengthens the mixing and heat exchange of cold and hot airflows, and is more beneficial to reducing the temperature of the flue gas to a lower level.

Referring to fig. 4(a is flue gas, b is high-speed air flow), the space between the outer ring 60 of the high-speed air flow outlet and the inner ring 62 of the high-speed air flow outlet of the coanda effect air inducing device 42 is hollow, forming an annular air flow space, the side opposite to the incoming flow direction of the flue gas of the electric arc furnace is sealed, the side same as the incoming flow direction of the flue gas of the electric arc furnace is the annular high-speed air flow outlet 61, and the air outlet is an annular slit. After being pressurized by a fan connected with the brushless motor 57, the air flow flows into an annular cylindrical air flow space between an outer ring 60 of a high-speed air flow outlet and an inner ring 62 of the high-speed air flow outlet from a compressed air output pipeline 58, the flow speed is increased at the small-section air outlet due to the reduction of the area of a flow channel, and the air flow is sprayed out through an annular slit of the air outlet to form a high flow speed so as to drive the flow of surrounding air, thereby forming negative pressure, inducing the movement of high-temperature flue gas in a flue of the electric arc furnace, causing forced convection heat exchange and accelerating the.

The wall attachment effect air inducing device 42 is positioned between the two sections of the electric arc furnace flues 4, the outer ring 60 of the high-speed airflow air outlet is flush with the electric arc furnace flues 4, the annular column-shaped airflow space is positioned in the electric arc furnace flues 4, the air suction side 41 of the wall attachment effect air inducing device is connected with the electric arc furnace flues 4, and high-temperature flue gas passes through the annular column-shaped airflow space; the air outlet side 48 of the coanda effect air guide is connected not only to the subsequent flue 4 of the electric arc furnace, but also to the semiconductor cooling module 49, which is followed by a flow of hot flue gas mixed with cold, low-humidity compressed air, which has a lower temperature than the preceding flow, but a higher kinetic energy and a faster flow rate.

The addition of the air suction side 41 of the wall attachment effect air inducing device can accelerate the air flow entrainment effect, accelerate the mixing and heat exchange of cold air and hot air, prevent the smoke dust easy to adhere from attaching to the cold end of the semiconductor refrigeration to reduce the refrigeration efficiency, and overcome the partial resistance of the bag-type dust collector 54. The coanda effect uses only a small amount of compressed air as a power source to drive surrounding air to flow to form high-pressure and high-speed airflow, and the flow rate is 50 times of the air consumption. Simple and easy to use, low cost, and can be used for conveying air, removing waste gas, discharging smoke, conveying light materials, and the like. The compressed air flows into the annular chamber through the inlet and then through the annular nozzle at high velocity, and this primary air flow is attracted to the contoured surface, thereby creating a low pressure region in the center of the chamber, whereby a large volume of ambient air is drawn in, and the primary air flow and ambient air flow combine to form a high velocity, high volume air flow exiting the air amplifier.

The whole device provides refrigerating capacity by virtue of an absorption heat pump and a semiconductor, a turbofan fan positioned in an air inducing device with an attached wall effect is used for absorbing cold air from an absorption heat pump unit, the cold air is pressurized inside the device and then is sprayed out from an annular outflow channel to form high-speed airflow to absorb a large amount of airflow from a flue, the flow velocity of the airflow is accelerated, strong mixing of cold and hot airflow is formed, meanwhile, heat exchange between the airflow and a semiconductor component is strengthened, the flue gas is rapidly cooled, meanwhile, the flue gas is prevented from being adhered to the surface of the semiconductor refrigerating component, and the relative humidity of the flue gas treated by a dry cooling mode is not increased but also reduced to a certain extent, so that the device is suitable for cloth bag dust. The cloth bag dust removal efficiency is higher, although the resistance is larger, the air after the wall attachment effect treatment still provides enough kinetic energy for the original air of the flue to overcome the resistance of the cloth bag dust remover, so that the dioxin content and the dust content in the final flue gas can be greatly reduced.

As shown in fig. 5-7, the semiconductor refrigeration module 49 is mainly composed of a semiconductor refrigeration module refrigerant input pipe 51, a semiconductor refrigeration module refrigerant output pipe 53, a semiconductor refrigeration power supply box 46, a semiconductor refrigeration power supply lead 47, a semiconductor element power supply lead 63, a semiconductor refrigeration power supply device 71, and a cold-end heat-conducting ceramic 66, a cold-end metal plate 65, an n-type semiconductor 64, a p-type semiconductor 67, a hot-end metal plate 68, a hot-end heat-conducting ceramic 69, a dividing wall type heat exchanger 70, and other components or structures which are sequentially arranged from inside to outside. The semiconductor refrigeration module refrigerant input pipe 51 and the semiconductor refrigeration module refrigerant output pipe 53 are connected to the dividing wall type heat exchanger 70. The semiconductor refrigeration module 49 is in a ring column shape and is arranged between two sections of electric arc furnace flues 4, as shown in figure 5, flue gas passes through the center, and the innermost layer is cold-end heat conducting ceramic 66 which is in contact with the flue gas for heat exchange. The main purpose is to further cool the flue gas of the electric arc furnace after mixing the cold air flow and the hot air flow, and more rapidly cool the flue gas to below 200 ℃ so as to reduce the generation of dioxin.

Semiconductor refrigeration is a new refrigeration technology based on five thermoelectric effects, namely the Seebeck effect, the Peltier effect, the Thomson effect, the Joule effect and the Fourier effect. In a closed loop formed by two different conductors, if current exists, the heat of one section connected with the conductors can be transferred to the other end, so that a cold end and a hot end are formed, and the refrigeration and heating effects are realized. The semiconductor has no noise and no liquid or gaseous working medium in the working process, so the semiconductor does not pollute the environment, the refrigeration parameters are not influenced by the space direction and the gravity, and the semiconductor can normally work under the condition of large mechanical overload; the refrigeration rate can be conveniently adjusted by adjusting the working current; by switching the current direction, the refrigerator can be changed from a refrigeration state to a heating working state combining the refrigeration technology of the refrigeration and absorption heat pump; the action speed is fast, the service life is long, and the control is easy. The semiconductor refrigeration can be efficiently adapted to the characteristics of large and discontinuous flue gas amount in the steelmaking process of the electric arc furnace, and the refrigeration effect can be better reflected.

The semiconductor refrigeration module 49 does not have a refrigerant inside, and is typical electric refrigeration, although the semiconductor refrigeration module refrigerant input pipeline 51 (the semiconductor refrigeration module refrigerant inlet 50 is communicated with the evaporator refrigerant outlet 36) and the semiconductor refrigeration module refrigerant output pipeline 53 (the semiconductor refrigeration module refrigerant outlet 52 is communicated with the absorber refrigerant inlet 35) are internally circulated with a gaseous refrigerant, the refrigerant has the function of performing partition-wall type heat exchange with the hot end heat conducting ceramic 69 of the semiconductor refrigeration module 49 through the partition-wall type heat exchanger 70, the heat generated at the hot end of the semiconductor refrigeration module is taken away in time through the low-temperature gaseous refrigerant, the efficiency of semiconductor refrigeration is improved, meanwhile, the sensible heat recovery is performed on the part of heat through the gaseous refrigerant, the temperature of the gaseous refrigerant entering the absorber 34 is indirectly improved, and the COP improvement of the absorption heat pump unit is greatly facilitated, meanwhile, the refrigerating efficiency of semiconductor refrigeration can be directly improved, and double effects are achieved. The semiconductor refrigeration and absorption heat pump unit is combined to achieve double optimization effects, which is not related to the prior art.

The refrigerating capacity of a single semiconductor refrigerating module is limited, and the amount of smoke required to be processed is large, so that a plurality of semiconductor refrigerating modules are combined in series (as shown in figure 7), and stronger refrigerating capacity is realized. The semiconductor refrigeration can be adopted to timely cope with the characteristics of unstable and discontinuous flue gas amount in the steelmaking process of the electric arc furnace, and the semiconductor refrigeration module is easy to realize automatic control, and the refrigerating capacity can be adjusted in time, so that the semiconductor refrigeration module can adapt to the characteristics of the flue gas of the electric arc furnace.

The invention uses heat conduction oil and water as energy transmission media, adopts the heat pipe to intensively and efficiently extract energy, transmits the energy required by each functional component to the corresponding part, simultaneously utilizes the absorption heat pump, the waste heat recovery and the refrigeration function, and cooperates with the refrigeration function of a semiconductor to form a three-section processing means for the waste heat recovery section, the rapid dry cooling section and the cloth bag dust removal section of the dioxin in the flue, thereby reducing the emission and the harm of the dioxin.

The invention can effectively reduce the content of dioxin in the flue gas of the electric arc furnace, and the main functions of the invention comprise the following two aspects:

(1) in the smelting period with less smoke gas amount, such as the initial stage of electric arc furnace steelmaking, the final stage of smelting and the like, the smoke gas amount in the electric arc furnace is less in the stage, but the temperature is different, so that the way of the device to play a role is different, and the device is divided into the following two aspects:

the flue gas volume in the flue of the electric arc furnace is less, and the temperature is not very high, and the stage can be the initial stage of electric arc furnace smelting, mainly carries out the preheating of conduction oil, and can carry out the semiconductor refrigeration of partial region. The first valve 5 and the third valve 12 are opened, and the fourth valve 13 is closed; any valve of the second valve 11 and the fifth valve 43 is opened or both valves are opened, the absorption heat pump unit does not work, and heat of the flue gas is recovered and stored through heat conduction oil. The heat conduction oil has certain thermal capacity, and heat can be stored by the heat conduction oil at first, so that the temperature of the heat conduction oil is increased, and the heat conduction oil is preheated. At this time, the flue gas still needs to be rapidly quenched after being subjected to heat recovery by the heat conduction oil, so that the semiconductor refrigeration loop still needs to work. Although the semiconductor refrigeration loop is coupled with the whole, the semiconductor refrigeration module 49 can be controlled independently, because the circuit is independent and only the control circuit is needed to realize the control. The fluid inside the coanda effect air inducing device 42 is low-temperature air when the absorption heat pump unit is started to operate, and the absorption heat pump unit does not work and cannot generate low-temperature air at present, so the fluid inside the coanda effect air inducing device 42 is normal-temperature air, and the temperature of the evaporator is not reduced although the normal-temperature air flows through the evaporator 37, so the normal-temperature air does not undergo temperature drop when flowing through the evaporator 37, but the temperature of flue gas is not high at this time, the amount of flue gas is not large, and the required compression induced air amount is not large, so the air amount to be compressed can be controlled by adjusting the opening degree of the low-temperature air flow control switch 56 inside the coanda effect air inducing device 42. Under the condition that the temperature of the flue gas is not high and the quantity is not large, a heat conduction oil circulation loop needs to be started.

In the process of steelmaking by an electric arc furnace, when the amount of flue gas is small and the temperature of the flue gas is high in the smelting stages, such as the final stage of smelting, the temperature of the flue gas is high in the stages, heat conducting oil is fully preheated in the early stage, the potential of being incapable of or recycling sensible heat is limited, at the moment, an absorption heat pump unit needs to be started, sensible heat of the flue gas is recycled, the waste heat of the high-temperature flue gas is utilized for refrigeration, low-temperature induced air is obtained and mixed with the high-temperature flue gas, the temperature of the high-temperature flue gas is rapidly reduced to be below the generation temperature of dioxin, and therefore the dioxin content of. In this stage, because the temperature of the flue gas is higher, the condition that the cooling capacity is insufficient when the flue gas is cooled by the self waste heat of the flue gas can exist, and the requirement cannot be met, so that the semiconductor refrigeration module can be started in stages according to the condition of the flue gas under the condition that the temperature of the flue gas is higher but the cooling capacity is not very large. The specific working process is as follows:

the first valve 5 and the fourth valve 13 are opened; and any one of the second valve 11 and the fifth valve 43 is opened, the third valve 12 is closed, and the heat conduction oil pump 6 is opened, namely, the heat conduction oil circulation loop is opened. The heat from the heat conduction oil is obtained in the heat conduction oil pool 22, and the heat is transmitted to the generator 28 of the absorption heat pump unit by means of the high-temperature heat pipe 15, the absorption heat pump unit starts to work after receiving the external input heat, the internal refrigerant starts to circulate, and by means of the phase change process of the internal refrigerant, the evaporator 37 of the absorption heat pump unit absorbs the heat of the external coil of the evaporator 37 due to the gasification process of the internal refrigerant, so as to reduce the temperature of the evaporator 37, the cold air from the evaporator 37 is absorbed by the negative pressure suction effect of the wall attachment effect air inducing device 42 and is gathered therein, and is ejected at high speed from the air outlet side 48 of the wall attachment effect air inducing device, meanwhile, the flue gas from the flue of the electric arc furnace is sucked by the air suction side 41 of the wall attachment effect air suction device, and the mutual mixing of cold and hot fluids is strengthened, so that the effect of quickly cooling the flue gas of the electric arc furnace is achieved. If the temperature of the flue gas subjected to the temperature reduction treatment by the method does not meet the requirement, the semiconductor refrigeration module needs to be started, the cold input is increased, and the effect of rapidly reducing the temperature of the flue gas and meeting the requirement is achieved.

(2) In the middle stage of smelting of electric arc furnace steelmaking, the flue gas volume is great, and when the temperature is higher, need open absorption heat pump unit and semiconductor refrigeration module simultaneously to increase the flow of conduction oil, the specific flow is as above, does not describe here one by one.

The foregoing is considered as illustrative of the preferred embodiments of the invention and is not to be construed as limiting the invention in any way. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention should fall within the protection scope of the technical scheme of the present invention, unless the technical spirit of the present invention departs from the content of the technical scheme of the present invention.

Claims

1. A device for rapidly cooling and treating dioxin for an electric arc furnace is characterized by comprising a waste heat recovery section and a flue gas rapid dry cooling section;

2. The apparatus for rapid cooling treatment of dioxin in electric arc furnace as claimed in claim 1, wherein a wall attachment effect air inducing apparatus is provided in the flue of the electric arc furnace between the waste heat recovery section and the flue gas rapid dry cooling section, the wall attachment effect air inducing apparatus includes a high-speed air outflow part and a compressed air output pipeline;

3. The apparatus for quenching treatment of dioxin in claim 1 or 2 for electric arc furnace, wherein the part of the heat conducting oil circulation loop in the flue of electric arc furnace is spiral.

4. The apparatus for quenching treatment of dioxin in accordance with claim 2, wherein the heat-conducting oil circulation circuit includes a main circuit, on which a first valve and a heat-conducting oil pump are installed, the main circuit being divided into a first branch and a second branch, the first branch being provided with a third valve, the second branch being provided with a fourth valve and a heat-conducting oil pool, the first branch and the second branch being merged into the main circuit and being divided into a third branch and a fourth branch, the third branch being provided with a second valve and an oil storage tank, the fourth branch being provided with a fifth valve, and the third branch and the fourth branch being merged into the main circuit; the heat-conducting oil pool is used as a high-temperature heat source for driving the generator.

5. The apparatus for quenching treatment of dioxin in arc furnace according to claim 4, wherein the heat-conducting oil tank is provided with high temperature heat pipes to transfer the heat of the heat-conducting oil to the generator.

6. The apparatus for quenching treatment of dioxin in electric arc furnace as claimed in claim 1 or 2, wherein the absorption heat pump unit is provided with a lithium bromide solution heat exchanger for preheating the low temperature lithium bromide dilute solution from the absorber by the high temperature lithium bromide concentrated solution outputted from the generator.

7. The apparatus for quenching treatment of dioxin in the electric arc furnace according to claim 1 or 2, wherein the section of the semiconductor refrigeration module is annular and is disposed between two sections of flue ducts of the electric arc furnace.

8. The apparatus for quenching treatment of dioxin in electric arc furnace according to claim 1 or 2, wherein the semiconductor refrigeration module is formed by combining a plurality of semiconductor refrigeration modules in series.

9. The apparatus for rapidly cooling and treating dioxin in electric arc furnaces according to claim 1 or 2, wherein the flue gas rapid drying and cooling section is connected with a bag dust removal section.

10. Use of the device of claim 4 for the remediation of dioxins, wherein: