Waste heat efficient utilization system of sintering circular cooler

Abstract

The utility model discloses an efficient waste heat utilization system for a sintering circular cooler. Waste gas outlets of the section I and the section II of the circular cooler are communicated with a waste gas inlet of the waste heat boiler; a waste gas outlet of the waste heat boiler is communicated with an air inlet of the first circulating fan and an I-section air bellow and an II-section air bellow of the circular cooler; air inlets of the first cooling fan and the second cooling fan are communicated with the environment; an air outlet of the first cooling fan is sequentially communicated with waste gas outlets of a V-section air bellow and a III-section air bellow of the circular cooler; an air outlet of the second cooling fan is sequentially communicated with the IV-section air box of the circular cooler, the second circulating fan and the IV-section air box of the circular cooler; and a waste gas outlet of the III-section air bellow of the circular cooler is communicated with a hot air cover of the sintering machine.

Description

Technical Field

[0001] The utility model relates to a system for efficiently utilizing waste heat of a sintering ring cooler. Background Art

[0002] In recent years, with the continuous improvement of national environmental protection requirements, steel companies have vigorously implemented technological transformation in accordance with the ultra-low emission requirements of atmospheric pollutants. Among them, the ring cooler, as a process of sintering and smelting, has long been emitting a large amount of dusty waste gas, especially in the medium and low temperature sections. Due to the low grade of waste heat, the recovery value is not as good as that in the high temperature section, so most steel companies do not recycle it. In the medium and low temperature sections, ring coolers are generally used to inhale cold air from the environment to cool the mine, and the medium and low temperature waste gas generated is directly discharged through the chimney. Under the current and even future increasingly stringent environmental protection situation, this treatment method will be gradually eliminated, and corresponding process improvements must be made to respond to policy requirements.

[0003] At present, zero emission of waste gas from annular coolers has been first implemented in Hebei and other regions, which has attracted close attention from relevant practitioners in the industry. It is expected that it will be gradually promoted to more provinces in the future. The waste gas from annular coolers contains a lot of dust particles and carries a lot of waste heat. How to balance waste heat recovery and pollutant control to achieve both economic and environmental benefits is a technical issue that steel companies are particularly concerned about. Utility Model Content

[0004] In view of the above problems, the utility model provides a system for efficiently utilizing waste heat of a sintering ring cooler.

[0005] To achieve the above-mentioned purpose, the sintering ring cooler waste heat efficient utilization system of the utility model at least includes a ring cooler, a waste heat boiler, a first circulation fan, a second cooling fan, a second circulation fan, a first cooling fan, and an exhaust valve;

[0006] The annular cooler is divided into sections I, II, III, IV and V according to the temperature of the sintered ore from high to low. The exhaust gas outlets of sections I and II of the annular cooler are connected to the exhaust gas inlet of the waste heat boiler; the exhaust gas outlet of the waste heat boiler is connected to the air inlet of the first circulating fan, and the air outlet of the first circulating fan is divided into two routes, which are respectively connected to the wind boxes of sections I and II of the annular cooler, forming the smoke and air circulation of sections I and II of the annular cooler;

[0007] The air inlet of the second cooling fan is connected to the outdoor environment to draw natural air from the atmosphere; the air outlet of the second cooling fan is connected to the IV section wind box of the ring cooler; the IV section exhaust gas outlet of the ring cooler is connected to the second circulation fan and the III section wind box of the ring cooler in sequence; the III section exhaust gas outlet of the ring cooler is connected to the hot air hood of the sintering machine to deliver the medium-temperature exhaust gas to the top of the material surface of the sintering machine for hot air sintering;

[0008] The air inlet of the first cooling fan communicates with the outdoor environment to suck natural air from the atmosphere; the air outlet of the first cooling fan communicates with the fifth-stage air box of the annular cooler; the fifth-stage waste gas outlet of the annular cooler communicates with the third-stage waste gas outlet of the annular cooler through a waste gas valve.

[0009] Further, a multi-tube dust collector and an induced draft fan are sequentially arranged along the waste gas flow on the pipeline after the mixing point of the third-stage waste gas outlet and the fifth-stage waste gas outlet of the annular cooler.

[0010] Further, the pipeline of the second-stage waste gas outlet of the annular cooler is connected to the inlet of the induced draft fan through a draft pipe.

[0011] Further, a draft valve is arranged on the draft pipe.

[0012] Further, a cold air supplement pipeline is arranged on the air inlet pipeline of the first circulating fan. One end of the cold air supplement pipeline communicates with the outdoor environment, and the other end communicates with the air inlet pipeline of the first circulating fan; a cold air valve is arranged on the cold air supplement pipeline.

[0013] Further, the waste gas valve is of a switch type, the draft valve is of an adjustment type, and the cold air valve is of an adjustment type.

[0014] Further, the first circulating fan, the second cooling fan, the second circulating fan, and the first cooling fan adopt frequency conversion adjustment.

[0015] Further, the waste heat boiler is a dual-pressure and dual-channel steam waste heat boiler. The high-temperature air inlet channel and the medium-temperature air inlet channel communicate with the first-stage waste gas outlet and the second-stage waste gas outlet of the annular cooler respectively; the waste heat boiler generates steam of two qualities, high pressure and low pressure, which is used to drive a steam turbine to generate electricity or drive the main sintering exhaust fan.

[0016] To achieve the above object, the method for efficient utilization of waste heat of a sintering annular cooler based on zero emission of waste gas of the present invention is characterized in that the method includes the following steps:

[0017] The first circulating fan operates at a high load, and the waste heat of the high-temperature and medium-temperature waste gas in the first stage and the second stage of the annular cooler is recovered through the waste heat boiler to generate steam for driving a steam turbine to generate electricity or do work, realizing the efficient utilization of high-grade heat energy; the cold air valve is opened, and the cold air supplement pipeline supplements cold air to the inlet of the first circulating fan to supplement the air leakage in the first stage and the second stage of the annular cooler, and the opening degree of the cold air valve is adjusted according to the air leakage amount in the first stage and the second stage of the annular cooler;

[0018] The second cooling fan and the second circulation fan operate at high load. The medium and low temperature waste heat of the third and fourth sections of the annular cooler is heated in series, and medium-temperature hot air with a relatively high temperature is generated at the outlet of the third section. The first cooling fan operates at a predetermined load, and the exhaust gas valve is opened. The low-temperature exhaust gas at the outlet of the fifth section of the annular cooler is introduced into the exhaust gas pipeline of the third section, generating hot air with a moderate temperature for hot air sintering, achieving efficient utilization of medium and low temperature waste heat. The first cooling fan adopts variable frequency regulation, and its load rate is controlled according to the temperature of the ore discharged from the annular cooler and the temperature of the exhaust gas mixed and sent to the hot air hood of the sintering machine, so as to ensure that the final ore discharge temperature of the annular cooler does not exceed the set value, and to ensure that the temperature of the exhaust gas sent to the hot air hood of the sintering machine does not exceed the upper limit of the allowable temperature for hot air sintering.

[0019] To achieve the above object, the method for efficient utilization of waste heat of the sintering annular cooler of the present invention is characterized in that the method includes the following steps:

[0020] The first circulation fan operates at high load. The high and medium temperature waste heat of the first and second sections of the annular cooler is recovered by a waste heat boiler, generating steam for driving a steam turbine to generate electricity or do work, achieving efficient utilization of high-grade heat energy. The cold air valve is opened, and the cold air supply pipeline supplies cold air to the inlet of the first circulation fan to supplement the air leakage in the first and second sections of the annular cooler and the air volume blown out by the air blowing pipe. The opening degree of the cold air valve is adjusted according to the air leakage volume and the air blowing volume.

[0021] The second cooling fan and the second circulation fan are put into operation. The medium and low temperature waste heat of the third and fourth sections of the annular cooler is heated in series, and medium-temperature hot air with a relatively high temperature is generated at the outlet of the third section for hot air sintering, achieving efficient utilization of medium and low temperature waste heat. The first cooling fan is shut down, and the exhaust gas valve is closed. The second cooling fan and the second circulation fan adopt variable frequency regulation and are coordinated and controlled. Their load rates are adjusted according to the temperature of the ore discharged from the annular cooler and the temperature of the exhaust gas mixed and sent to the hot air hood of the sintering machine, so as to ensure that the final ore discharge temperature of the annular cooler does not exceed the set value, and to ensure that the temperature of the exhaust gas sent to the hot air hood of the sintering machine does not exceed the upper limit of the allowable temperature for hot air sintering.

[0022] The air blowing valve is opened, and the air blowing pipe leads the exhaust gas at the outlet of the second section of the annular cooler to the inlet of the induced draft fan, and after mixing with the exhaust gas at the outlet of the multi-tube dust collector, they enter the induced draft fan together.

[0023] Based on the concept of zero exhaust gas emission of the annular cooler, the present invention fully combines the sectional waste heat characteristics of the annular cooler, recovers the high and medium temperature waste heat of the annular cooler through a waste heat boiler, generates steam that can be used to drive a steam turbine to generate electricity or do work, achieving efficient utilization of high-grade heat energy; heats the medium and low temperature waste heat of the annular cooler in series to generate medium-temperature hot air with a relatively high temperature for hot air sintering, achieving efficient utilization of medium and low temperature waste heat.

[0024] According to the temperature characteristics of sinter, the utility model adopts stepped cooling. The sinter in the high-temperature section is cooled by air at a higher temperature, and the sinter in the low-temperature section is cooled by air at a lower temperature, which can reduce the breakage rate during the cooling process of sinter and improve the finished product rate of sinter.

[0025] The utility model is provided with a multi-tube dust collector and an induced draft fan to purify and pressurize the waste gas used for hot air sintering. Compared with the non-powered transportation method of directly introducing the waste gas into the hot air hood of the sintering machine, the induced draft power is increased, and the implementation effect of hot air sintering is strengthened; the setting of the multi-tube dust collector can not only improve the production environment at the hot air hood of the sintering machine, but also increase the negative pressure at the inlet of the induced draft fan, providing conditions for the extraction of medium-temperature waste gas in the second section of the annular cooler (otherwise, it is difficult for the waste gas in the second section to mix into the waste gas pipeline in the third section).

[0026] The utility model designs reliable adjustment means. Through the opening and closing combination and operation coordination of the second cooling fan, the second circulation fan, the first cooling fan, the waste gas valve, and the extraction valve, different working conditions can be met, and the "three simultaneous" benefits of sinter cooling, zero waste gas emission, and efficient utilization of waste heat can be achieved under various conditions. The utility model is especially suitable for annular coolers with a relatively high inlet ore temperature and good sealing effect, and it is very convenient to adjust the operation in combination with weather conditions. Description of the Drawings

[0027] Figure 1 It is a structural schematic diagram of a system and method for efficient utilization of waste heat of a sintering annular cooler;

[0028] In the figure, 1. Annular cooler; 2. Waste heat boiler; 3. First circulation fan; 4. Second cooling fan; 5. Second circulation fan; 6. First cooling fan; 7. Waste gas valve; 8. Multi-tube dust collector; 9. Induced draft fan; 10. Extraction pipe; 11. Extraction valve; 12. Supplementary cold air pipeline; 13. Cold air valve. Specific Embodiments

[0029] The embodiments of the utility model will be described in detail below with reference to the drawings.

[0030] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0031] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, the meaning of "a plurality" is two or more.

[0032] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "joined" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0033] Embodiment 1

[0034] The high-efficiency waste heat utilization system of the sintering annular cooler of the present utility model at least includes an annular cooler, a waste heat boiler, a first circulation fan, a second cooling fan, a second circulation fan, a first cooling fan, and an exhaust gas valve.

[0035] The annular cooler 1 is divided into section Ⅰ, section Ⅱ, section Ⅲ, section Ⅳ, and section Ⅴ according to the temperature of the sintered ore from high to low. The exhaust gas outlets of section Ⅰ and section Ⅱ of the annular cooler 1 are communicated with the exhaust gas inlets of the waste heat boiler 2; the exhaust gas outlet of the waste heat boiler 2 is communicated with the air inlet of the first circulation fan 3, and the air outlet of the first circulation fan 3 is divided into two paths and is respectively communicated with the air boxes of section Ⅰ and section Ⅱ of the annular cooler 1 to form the flue gas and air circulation of section Ⅰ and section Ⅱ of the annular cooler.

[0036] The air inlet of the second cooling fan 4 is communicated with the outdoor environment to suck natural air from the atmosphere; the air outlet of the second cooling fan 4 is communicated with the air box of section Ⅳ of the annular cooler 1; the exhaust gas outlet of section Ⅳ of the annular cooler 1 is successively communicated with the second circulation fan 5 and the air box of section Ⅲ of the annular cooler 1; the exhaust gas outlet of section Ⅲ of the annular cooler 1 is communicated with the hot air hood of the sintering machine to send the medium-temperature exhaust gas above the sintering machine material surface for hot air sintering;

[0037] The air inlet of the first cooling fan 6 is communicated with the outdoor environment to suck natural air from the atmosphere; the air outlet of the first cooling fan 6 is communicated with the air box of section Ⅴ of the annular cooler 1; the exhaust gas outlet of section Ⅴ of the annular cooler 1 is communicated with the exhaust gas outlet of section Ⅲ of the annular cooler 1 through the exhaust gas valve 7.

[0038] Embodiment 2

[0039] As an improvement to the above embodiments, on the pipeline after the mixing point of the exhaust gas outlets of the III section and the V section of the annular cooler 1, a multi-tube dust collector 8 and a induced draft fan 9 are successively arranged along the exhaust gas flow direction. The multi-tube dust collector 8 is used to remove dust particles in the exhaust gas, and the induced draft fan 9 is used to overcome the frictional resistance along the exhaust gas pipeline to send the exhaust gas to the hot air hood of the sintering machine.

[0040] Embodiment 3

[0041] As an improvement to the above embodiments, the exhaust gas outlet pipeline of the II section of the annular cooler 1 is communicated with the inlet of the induced draft fan 9 through an air diversion pipe 10; an air diversion valve 11 is arranged on the air diversion pipe 10 for adjusting the amount of medium-temperature air introduced from the exhaust gas of the II section of the annular cooler.

[0042] Embodiment 4

[0043] As an improvement to the above embodiments, a cold air supplement pipeline 12 is arranged on the air inlet pipeline of the first circulation fan 3. One end of the cold air supplement pipeline 12 is communicated with the outdoor environment, and the other end is communicated with the air inlet pipeline of the first circulation fan 3; a cold air valve 13 is arranged on the cold air supplement pipeline 12.

[0044] In the above embodiments, the exhaust gas valve 7 is of the on-off type, the air diversion valve 11 is of the regulating type, and the cold air valve 13 is of the regulating type; the first circulation fan 3, the second cooling fan 4, the second circulation fan 5, and the first cooling fan 6 all adopt variable frequency regulation;

[0045] The waste heat boiler 2 is a dual-pressure and dual-channel steam waste heat boiler. The high-temperature air inlet channel and the medium-temperature air inlet channel are respectively communicated with the exhaust gas outlets of the I section and the II section of the annular cooler 1; the waste heat boiler 2 generates steam of two qualities, high pressure and low pressure, which is used to drive a steam turbine to generate electricity or drive the main exhaust fan of the sintering machine.

[0046] Embodiment 5

[0047] The method for highly efficient utilization of waste heat of a sintering annular cooler based on zero emission of exhaust gas of the present invention:

[0048] Condition 1 (applicable to conditions such as the sintered ore temperature falling into the annular cooler being on the high side or in the high-temperature season, resulting in a need for a large amount of cooling air volume and the first cooling fan 6 needs to be turned on):

[0049] The first circulation fan 3 operates at a high load. The waste heat of the high- and medium-temperature exhaust gas in the I section and the II section of the annular cooler 1 is recovered through the waste heat boiler to generate steam that can be used to drive a steam turbine to generate electricity or do work, realizing the highly efficient utilization of high-grade heat energy; the cold air valve 13 is opened, and the cold air supplement pipeline 12 supplements cold air to the inlet of the first circulation fan 3 to make up for the air leakage in the I section and the II section of the annular cooler 1. The opening degree of the cold air valve 13 is adjusted according to the air leakage amount in the I section and the II section of the annular cooler 1;

[0050] The second cooling fan 4 and the second circulation fan 5 operate at high load. The medium and low temperature waste heat of the third and fourth sections of the annular cooler 1 is heated in series, and medium-temperature hot air with a relatively high temperature is generated at the outlet of the third section. The first cooling fan 6 is put into operation, and the exhaust gas valve 7 is opened. The low-temperature exhaust gas at the outlet of the fifth section of the annular cooler 1 is introduced into the exhaust gas pipeline of the third section, generating hot air with a moderate temperature for hot air sintering, realizing the efficient utilization of medium and low temperature waste heat. The first cooling fan 6 adopts frequency conversion regulation, and its load rate is controlled according to the temperature of the ore discharged from the annular cooler and the temperature of the exhaust gas sent to the hot air hood of the sintering machine after mixing. On the one hand, it is necessary to ensure that the final ore discharge temperature of the annular cooler does not exceed the set value, and on the other hand, it is necessary to ensure that the temperature of the exhaust gas sent to the hot air hood of the sintering machine does not exceed the upper limit of the allowable temperature for hot air sintering (such as 300 °C).

[0051] Example 6

[0052] The method for efficient utilization of waste heat of a sintering annular cooler based on zero exhaust gas emission of the present utility model:

[0053] Condition 2 (applicable to the situation where the temperature of the sintered ore falling into the annular cooler is slightly lower or in cold winter weather, etc., resulting in a low required cooling air volume and the first cooling fan 6 can be shut down):

[0054] The first circulation fan 3 operates at high load. The high and medium temperature waste heat of the first and second sections of the annular cooler 1 is recovered by a waste heat boiler, generating steam that can be used to drive a steam turbine for power generation or work, realizing the efficient utilization of high-grade heat energy. The cold air valve 13 is opened, and the cold air supply pipeline 12 supplies cold air to the inlet of the first circulation fan 3 to supplement the air leakage in the first and second sections of the annular cooler 1 and the air volume extracted by the air extraction pipe 10. The opening degree of the cold air valve 13 is adjusted according to the air leakage volume and the air extraction volume;

[0055] The second cooling fan 4 and the second circulation fan 5 are put into operation. The medium and low temperature waste heat of the third and fourth sections of the annular cooler 1 is heated in series, and medium-temperature hot air with a relatively high temperature is generated at the outlet of the third section for hot air sintering, realizing the efficient utilization of medium and low temperature waste heat. The first cooling fan 6 is shut down, and the exhaust gas valve 7 is closed. Both the second cooling fan 4 and the second circulation fan 5 adopt frequency conversion regulation and are coordinately controlled. Their load rates are adjusted according to the temperature of the ore discharged from the annular cooler and the temperature of the exhaust gas sent to the hot air hood of the sintering machine after mixing. On the one hand, it is necessary to ensure that the final ore discharge temperature of the annular cooler does not exceed the set value, and on the other hand, it is necessary to ensure that the temperature of the exhaust gas sent to the hot air hood of the sintering machine does not exceed the upper limit of the allowable temperature for hot air sintering (such as 300 °C).

[0056] The air extraction valve 11 is opened, and the air extraction pipe 10 leads the waste gas at the outlet of the second section of the annular cooler to the inlet of the induced draft fan 9. After being mixed with the waste gas at the outlet of the multi-tube dust collector 8, they enter the induced draft fan together. Since the negative pressure at the inlet of the induced draft fan 9 is higher than the negative pressure in the waste gas pipeline at the outlet of the second section of the annular cooler, the air extraction pipe 10 and the air extraction valve 11 can play a function of flow distribution regulation. The function of setting the air extraction pipe 10 and the air extraction valve 11 is to perform corresponding air volume or air temperature compensation for the reduction of the waste gas flow at the outlet of the third section of the annular cooler and the possible problem of low air temperature under this working condition, so as to reduce the impact of this system on the production of the sintering machine.

[0057] The above scheme not only realizes the efficient utilization of the waste heat of the annular cooler but also realizes the near-zero emission of the waste gas of the annular cooler.

[0058] The above has described the present utility model in detail with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the gist of the present utility model. Many other changes and modifications made without departing from the concept and scope of the present utility model should be regarded as within the protection scope of the present utility model.

[0059] In the description of this specification, specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0060] The above is only the specific implementation manner of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model can easily think of changes or substitutions, which should all be covered by the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be subject to the protection scope of the said claims.

Claims

1. A high-efficiency waste heat utilization system for a sintering annular cooler, characterized in that, It includes at least a ring cooler, a waste heat boiler, a first circulation fan, a first cooling fan, a second circulation fan, a second cooling fan, and an exhaust gas valve; The ring cooler is divided into section Ⅰ, section Ⅱ, section Ⅲ, section Ⅳ, and section Ⅴ from high to low according to the temperature of the sintered ore. The exhaust gas outlets of section Ⅰ and section Ⅱ of the ring cooler are connected to the exhaust gas inlets of the waste heat boiler; the exhaust gas outlet of the waste heat boiler is connected to the air inlet of the first circulation fan. The air outlet of the first circulation fan is divided into two paths and is respectively connected to the air boxes of section Ⅰ and section Ⅱ of the ring cooler, forming a flue gas and air circulation for section Ⅰ and section Ⅱ of the ring cooler; The air inlet of the first cooling fan is connected to the outdoor environment to suck natural air from the atmosphere; the air outlet of the first cooling fan is connected to the air box of section Ⅴ of the ring cooler; the exhaust gas outlet of section Ⅴ of the ring cooler is connected to the exhaust gas outlet of section Ⅲ of the ring cooler through an exhaust gas valve; The air inlet of the second cooling fan is connected to the outdoor environment to suck natural air from the atmosphere; the air outlet of the second cooling fan is connected to the air box of section Ⅳ of the ring cooler; the exhaust gas outlet of section Ⅳ of the ring cooler is successively connected to the second circulation fan and the air box of section Ⅲ of the ring cooler; the exhaust gas outlet of section Ⅲ of the ring cooler is connected to the hot air hood of the sintering machine to send medium-temperature exhaust gas above the sintering machine material surface for hot air sintering.

2. The waste heat high-efficient utilization system of a sintering annular cooler according to claim 1, wherein A multi-tube dust collector and an induced draft fan are successively arranged on the pipeline after the mixing point of the exhaust gas outlets of section Ⅲ and section Ⅴ of the ring cooler along the exhaust gas flow direction.

3. The waste heat high-efficient utilization system of a sintering annular cooler according to claim 2, characterized in that The exhaust gas outlet pipeline of section Ⅱ of the ring cooler is connected to the inlet of the induced draft fan through a diverting air pipe.

4. The waste heat high-efficient utilization system of a sintering annular cooler according to claim 3, characterized in that, A diverting air valve is arranged on the diverting air pipe.

5. The waste heat high-efficient utilization system of a sintering annular cooler according to claim 1, wherein, A cold air supplement pipeline is arranged on the air inlet pipeline of the first circulation fan. One end of the cold air supplement pipeline is connected to the outdoor environment, and the other end is connected to the air inlet pipeline of the first circulation fan; a cold air valve is arranged on the cold air supplement pipeline.

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