CN112229230A - Heating furnace flue gas waste heat recovery system and combustion system - Google Patents
Heating furnace flue gas waste heat recovery system and combustion system Download PDFInfo
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- CN112229230A CN112229230A CN202011149334.7A CN202011149334A CN112229230A CN 112229230 A CN112229230 A CN 112229230A CN 202011149334 A CN202011149334 A CN 202011149334A CN 112229230 A CN112229230 A CN 112229230A
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- flue gas
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
- F23L15/00—Heating of air supplied for combustion
- F23L15/04—Arrangements of recuperators
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Abstract
The invention relates to the field of flue gas recovery processing of heating furnaces, in particular to a flue gas waste heat recovery system and a combustion system of a heating furnace. The spray cooling tower comprises a cooling tower body and a first spray device for spraying cooling liquid, wherein a flue gas inlet is formed in one side, relatively close to the tower bottom, of the cooling tower body, and the first spray device is arranged in the cooling tower body and relatively close to the tower top, so that convection is formed between the flue gas and the cooling liquid; the air humidification tower comprises an air humidifier body and a second spraying device for spraying liquid, an air inlet is formed in one side, close to the bottom of the tower, of the air humidifier body, the second spraying device is arranged in the air humidifier body and close to the top of the tower, a liquid outlet of the cooling tower body is connected with the second spraying device, convection is formed between air and liquid, and the air is heated and humidified. The waste heat of the flue gas of the heating furnace can be effectively recycled, and the content of NOx in the flue gas is reduced.
Description
Technical Field
The invention relates to the field of flue gas recovery processing of heating furnaces, in particular to a flue gas waste heat recovery system and a combustion system of a heating furnace.
Background
The heating furnace is an energy-consumption large household and a main discharge port of a refining enterprise, and has very important significance for improving the heat efficiency of the heating furnace, reducing the pollutant discharge amount, saving energy and reducing emission for the refining enterprise.
In the prior art, the waste heat of flue gas is generally recovered by adopting an air preheating mode, the utilization efficiency of energy is improved by reducing the loss of exhaust gas, but the exhaust gas temperature of the existing heating furnace is generally higher than 100 ℃. This is because if the flue gas temperature of the heating furnace is lower than 100 ℃, the conventional air preheater will suffer from low-temperature dew-point corrosion and cannot operate for a long time at the dew-point temperature. The existing low-temperature dew point corrosion resistant air preheater is expensive and low in heat exchange efficiency, the economic performance of recovering sensible heat of flue gas below 100 ℃ is poor, and the refining and chemical enterprises do not recover and utilize the part of waste heat. And when the temperature of the flue gas of the heating furnace is lower than 55 ℃, the water vapor in the flue gas reaches the dew point, and the water vapor is condensed to release a large amount of condensation latent heat. Because of huge heat and low temperature, the conventional air heat exchange can not recover the latent heat of condensation of the flue gas. Therefore, the existing air heat exchange mode is difficult to recover low-temperature sensible heat and latent heat of condensation of the flue gas, and further improvement of the heat efficiency of the heating furnace is restricted.
Meanwhile, with the strictness of national environmental protection regulations, the national standard regulates the emission of the heating furnace, and the NOx content in the flue gas of the process heating furnace is required to be not more than 100mg/m3The refining enterprises are sequentially reformed by the low-nitrogen combustion technology, the emission basically reaches the national standard at present, but the emission of NOx in the flue gas of the heating furnace is further reduced, and certain technical difficulty exists.
Disclosure of Invention
The invention aims to provide a heating furnace flue gas waste heat recovery system and a combustion system, for example, the heating furnace flue gas waste heat recovery system and the combustion system can effectively recycle the waste heat of the flue gas of a heating furnace and reduce the content of NOx in the flue gas by recovering the sensible heat and partial condensation latent heat of the flue gas through the humidification and the heating of combustion air.
Embodiments of the invention may be implemented as follows:
in a first aspect, an embodiment of the present invention provides a heating furnace flue gas waste heat recovery system, which includes a spray cooling tower and an air humidifying tower, wherein the spray cooling tower is connected to the air humidifying tower;
the spray cooling tower comprises a cooling tower body and a first spray device for spraying cooling liquid, wherein a flue gas inlet is formed in one side, relatively close to the tower bottom, of the cooling tower body, the first spray device is arranged in the cooling tower body and is positioned at one side, relatively close to the tower top of the cooling tower body, so that convection is formed between the flue gas and the cooling liquid, then the flue gas heats the cooling liquid, and the waste heat of the flue gas is recovered;
the air humidifying tower comprises an air humidifier body and a second spraying device for spraying liquid, the second spraying device is arranged in the air humidifier body and is located on one side, close to the tower top relatively, of the air humidifier body, the liquid outlet of the cooling tower body is connected with the second spraying device, an air inlet is formed in one side, close to the tower bottom relatively, of the air humidifier body, convection of air and liquid is formed, the liquid sprayed in the cooling tower body passes through the second spraying device, the air is heated and humidified, and the air humidifier body is provided with an air outlet for introducing the air after heating and humidification into the heating furnace.
In an optional embodiment, the air humidification tower further comprises a microporous gas distributor, the microporous gas distributor is arranged at the bottom of the tower inside the air humidifier body and connected with the air humidifier body, and the air inlet is communicated with the microporous gas distributor, so that air is uniformly distributed in the air humidifier body.
In an alternative embodiment, the microporous gas distributor is a membrane element;
preferably, a plurality of membrane tubes are arranged in the membrane element;
preferably, the equivalent diameter of the membrane tube is 10-70mm, the porosity of the membrane element is 50-80%, the pore diameter of the micropores of the membrane element is less than 1 μm, and the membrane on the membrane tube is a ceramic membrane or a hollow fiber membrane.
In an optional implementation mode, the air humidification tower further comprises an atomizer, the atomizer is arranged in the air humidifier body and connected with the air humidifier body, and the atomizer is located between the second spraying device and the micropore gas distributor, so that the atomizer cuts liquid sprayed by the second spraying device to form refined liquid drops.
In an optional embodiment, the atomizer is a grid type atomizer, the thickness of a grid is 5-30mm, and the equivalent diameter of grid holes is 0.1-10 mm;
preferably, the liquid outlet of the air humidifier body is connected with the first spraying device.
In an optional implementation manner, the spray cooling tower further comprises a spray heat exchanger, the spray heat exchanger is arranged between the flue gas inlet and the first spray device, the spray heat exchanger is connected with the cooling tower body, and an air inlet of the spray heat exchanger is communicated with an air outlet of the air humidifier body.
In an alternative embodiment, the spray heat exchanger is a tubular heat exchanger;
preferably, the tubular heat exchanger is a twisted tube or a spoiler is arranged in the tubular heat exchanger;
preferably, the pipe diameter of the pipe heat exchanger is 10-70 mm;
preferably, the liquid outlet of the cooling tower body is connected with the first spraying device;
preferably, the spray cooling tower comprises a guide plate for guiding the flue gas, the guide plate is arranged in the cooling tower body and connected with the cooling tower body, and the guide plate is arranged opposite to the flue gas inlet.
In an optional embodiment, the spray cooling tower further includes a condensing part for further condensing the flue gas, the condensing part is disposed in the cooling tower body and connected to the cooling tower body, and the condensing part is located between the first spraying device and the top of the cooling tower body;
preferably, the condensing part comprises a bottom plate, a flue gas ascending pipe and a third spraying device, the bottom plate is arranged between the first spraying device and the top of the cooling tower body, the bottom plate is fixedly connected with the cooling tower body, the flue gas ascending pipe is arranged on the bottom plate and is connected with the bottom plate, and the third spraying device is arranged between the bottom plate and the top of the cooling tower body, so that the flue gas contacts condensate sprayed by the third spraying device after passing through the flue gas ascending pipe;
preferably, a demister is further arranged between the third spraying device and the tower top of the cooling tower body;
preferably, the bottom plate is connected with the second spraying device, so that the liquid sprayed by the third spraying device can humidify and heat air;
preferably, the flue gas riser is a venturi tube.
In an optional embodiment, the heating furnace flue gas waste heat recovery system further comprises an air preheater, the air preheater is communicated with an air outlet of the air humidifying tower, and the air preheater is communicated with the flue gas inlet.
In a second aspect, an embodiment of the present invention provides a combustion system, which includes the heating furnace flue gas waste heat recovery system described in any one of the foregoing embodiments.
The embodiment of the invention has the beneficial effects that the embodiment of the invention can recover the low-temperature sensible heat and partial condensation latent heat of the flue gas by utilizing the combustion-supporting air without other cold sources through the spraying humidification and heating temperature rise of the combustion-supporting air, thereby effectively improving the comprehensive heat efficiency of the heating furnace. Simultaneously, through heating the humidification to the air, help promoting the vapor content of the air that gets into the heating furnace, reduce the content of nitrogen oxide in the flue gas that forms then.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic structural diagram of a heating furnace flue gas waste heat recovery system provided in embodiment 1 of the present invention;
fig. 2 is a schematic structural view of a baffle provided in embodiment 1 of the present invention;
fig. 3 is a schematic structural diagram of a heating furnace flue gas waste heat recovery system provided in embodiment 2 of the present invention;
fig. 4 is a schematic structural diagram of a combustion system provided in embodiment 2 of the present invention.
Icon: 100-a heating furnace flue gas waste heat recovery system; 110-spray cooling tower; 111-a cooling tower body; 112-flue gas inlet; 113-a first spray device; 114-spray heat exchanger; 115-a flow guide plate; 116-a demister; 120-air humidification column; 121-air humidifier body; 122-a second spray device; 123-an air inlet; 124-microporous gas distributor; 125-an atomizer; 130-an air preheater; 200-a heating furnace flue gas waste heat recovery system; 210-spray cooling tower; 211-a cooling tower body; 240-cooling section; 250-a condensation section; 212-flue gas inlet; 213-a first spray device; 214-a spray heat exchanger; 215-a baffle; 216-a demister; 260-a condensation section; 261-a bottom plate; 262-a flue gas riser; 263-third spraying device; 220-air humidification column; 221-an air humidifier body; 222-a second spray device; 230-an air preheater; 300-a combustion system; 310-heating furnace.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or a positional relationship based on that shown in the drawings or that the product of the present invention is used as it is, this is only for convenience of description and simplification of the description, and it does not indicate or imply that the device or the element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.
Furthermore, the appearances of the terms "first," "second," and the like, if any, are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
It should be noted that the features of the embodiments of the present invention may be combined with each other without conflict.
Example 1
Referring to fig. 1, the present embodiment provides a heating furnace flue gas waste heat recovery system 100, which includes a spray cooling tower 110, which includes a cooling tower body 111, a flue gas inlet 112 is disposed on one side of the cooling tower body 111 relatively close to the tower bottom, and then high temperature flue gas formed in the heating furnace enters the spray cooling tower 110 through the flue gas inlet 112, and then flue gas waste heat recovery is achieved.
It should be noted that the cooling tower body 111 is a conventional tower structure, and the tower structure is disposed on the ground, and the side relatively close to the ground is a tower bottom, and the side opposite to the tower bottom is a tower top.
The spray cooling tower 110 comprises a first spray device 113 for spraying cooling liquid, the first spray device 113 is arranged in the cooling tower body 111 and is located at one side of the top of the cooling tower body 111, then the cooling liquid sprayed by the first spray device 113 forms convection with the flue gas, the flue gas heats the cooling liquid, the cooling liquid cools the flue gas, and then the waste heat of the flue gas is fully utilized.
It should be noted that the initial cooling liquid sprayed by the first spraying device 113 is introduced through an external pipeline, or is directly added into the liquid in the cooling tower body 111, and when the heating furnace flue gas waste heat recovery system 100 works, no additional liquid is introduced, and the introduced liquid can be recycled as the cooling liquid, that is, the liquid outlet of the cooling tower body 111 is connected with the first spraying device 113, and the liquid outlet of the air humidifier body 121 is connected with the first spraying device 113, so that the liquid can be recycled, and resource waste is avoided. However, when the coolant is no longer in heat exchange with the flue gas, the coolant needs to be replaced.
Further, the spray cooling tower 110 further includes a spray heat exchanger 114, the spray heat exchanger 114 is disposed between the flue gas inlet 112 and the first spray device 113, and the spray heat exchanger 114 is connected to the cooling tower body 111, so that the flue gas flowing upward and the cooling liquid sprayed by the first spray device 113 flowing downward can further heat the air in the spray heat exchanger 114, and the heat exchange efficiency is higher than that of a conventional gas-gas heat exchanger. In addition, the sprayed cooling liquid has a good cleaning effect on the spray heat exchanger 114, so that the phenomenon of dust deposition and scaling of the heat exchanger can be prevented, and the long-period stable operation of the heat exchanger is ensured.
Further, the spray heat exchanger 114 is a tubular heat exchanger; the tubular heat exchanger is a twisted tube or is internally provided with a spoiler; the diameter of the pipeline of the tubular heat exchanger is 10-70 mm; adopt above-mentioned tubular heat exchanger can further promote the heat transfer effect.
Further, referring to fig. 2, flue gas of the heating furnace enters the cooling tower body 111 from the flue gas inlet 112, but the cooling tower body 111 is large and the flue gas is unevenly distributed, so that the part of the spray heat exchanger 114 relatively far away from the area of the flue gas inlet 112 can not well act on the flue gas, or the flue gas can not uniformly act on the liquid sprayed by the first spraying device 113, therefore, the spray cooling tower 110 comprises a guide plate 115, the guide plate 115 is arranged in the cooling tower body 111 and connected with the cooling tower body 111, and the guide plate 115 is arranged opposite to the flue gas inlet 112, so as to guide the flue gas, and the flue gas is evenly distributed. Preferably, the guide plate 115 has a fan-shaped structure, and the included angle α between the guide plate 115 and the tower wall of the cooling tower body 111 is 30-60 degrees, so as to ensure the flow guiding effect of the guide plate 115.
Further, a demister 116 is disposed between the first spray device 113 and the tower top of the cooling tower body 111.
In conclusion, by adopting the means for strengthening heat and mass transfer, the flue gas waste heat recovery device has strong waste heat recovery capability and high recovery efficiency, effectively improves the capability and efficiency of the combustion air for recovering the flue gas waste heat, and ensures that the sensible heat and partial condensation latent heat of the flue gas can be recovered by utilizing the combustion air.
Further, referring to fig. 1, the heating furnace flue gas waste heat recovery system 100 includes an air humidifying tower 120, the spray cooling tower 110 is connected to the air humidifying tower 120, specifically, the cooling tower body 111 is connected to the air humidifying tower 120, and an air outlet of the air humidifying tower 120 is connected to the spray heat exchanger 114, so that the heated and humidified air can be further heated, and the waste heat of the flue gas can be further recovered.
The air humidification tower 120 comprises an air humidifier body 121 and a second spraying device 122 for spraying liquid, the second spraying device 122 is arranged in the air humidifier body 121 and is positioned on one side relatively close to the top of the tower, a liquid outlet of the cooling tower body 111 is connected with the second spraying device 122, an air inlet 123 is arranged on one side relatively close to the bottom of the tower of the air humidifier body 121, so that convection current is formed between air and liquid, and the liquid sprayed in the cooling tower body 111 passes through the second spraying device 122 to heat and humidify the air. Meanwhile, the bottom of the air humidifier body 121 is provided with an air outlet through which heated and humidified air is introduced into the heating furnace.
Further, the second spraying device 122 is connected with the liquid outlet of the cooling tower body 111, then the cooling liquid sprayed by the first spraying device 113 can heat and humidify the air at normal temperature (about 20 ℃), and the liquid sprayed by the second spraying device 122 is accumulated in the air humidifier body 121 and is transported back to the cooling tower body 111 for recycling after being accumulated to a certain degree. The liquid accumulated in the air humidifier body 121 is adjusted according to actual conditions.
This connected mode is better connected mode, can effectively carry out recycle to the flue gas waste heat, but also can be connected second spray set 122 with the liquid outlet of air humidifier body 121 for the liquid cyclic utilization that accumulates in the air humidifier body 121, rather than circulate between air humidifying tower 120-the spray cooling tower 110.
Further, air humidification tower 120 still includes micropore gas distributor 124, micropore gas distributor 124 set up in air humidifier body 121, and with air humidifier body 121 is connected, just air inlet 123 with micropore gas distributor 124 intercommunication for air evenly distributed is in air humidifier body 121, and simultaneously, the liquid that submicron order gas and second spray set 122 sprayed passes through little interface direct contact, promotes heating and humidification effect.
Meanwhile, when the heating furnace flue gas waste heat recovery system 100 operates, the microporous gas distributor 124 is soaked in the accumulated liquid in the air humidifier body 121, so that the bubbles passing through the micropores can act on the liquid, and the heating and humidifying effects of the microporous gas distributor are improved.
Specifically, the microporous gas distributor 124 is a membrane element; a plurality of membrane tubes are arranged in the membrane element, so that air forms microbubbles with a size of less than 1 μm and enters the air humidifier body 121; the equivalent diameter of the membrane tube is 10-70mm, the porosity of the membrane element is 50-80%, the pore diameter of the micropores of the membrane element is less than 1 micron, and the membrane on the membrane tube is a ceramic membrane or a hollow fiber membrane. The micro-pore gas distributor 124 can ensure the formation of micro-bubbles, and is favorable for heating and humidifying air.
Simultaneously, the one end of film element is sealed, and one end is not sealed, makes then in the air gets into the film element through the one end that does not seal, and then can only get into this internal through the membrane of film element air humidifier, guarantees the formation of microbubble.
Further, the air humidification tower 120 further includes an atomizer 125, the atomizer 125 is disposed in the air humidifier body 121, and is connected with the air humidifier body 121, the atomizer 125 is located between the second spraying device 122 and the microporous gas distributor 124, so that the atomizer 125 cuts the liquid sprayed by the second spraying device 122, forms refined liquid drops, can further enlarge the air contact with the microbubbles, and accelerates the air humidification and heating efficiency.
Further, the atomizer 125 is a grid type atomizer, the thickness of the grid is 5-30mm, and the equivalent diameter of the grid hole is 0.1-10 mm; adopt above-mentioned structure can promote the atomizing effect.
The embodiment of the invention provides a strengthening means of micro-interface contact and fine liquid drop spraying contact, can realize zero-temperature-difference heat transfer and mass transfer, greatly improves the air humidifying efficiency and capacity, and is beneficial to recovering the latent heat of flue gas condensation by air.
Further, the heating furnace flue gas waste heat recovery system 100 further comprises an air preheater 130, the air preheater 130 is communicated with an air outlet of the air humidifying tower 120, the air preheater 130 is communicated with the flue gas inlet 112, specifically, an air outlet of the spray heat exchanger 114 is communicated with an air inlet of the air preheater 130, and a flue gas outlet of the air preheater 130 is communicated with the flue gas inlet 112, so that flue gas and air can perform gas-gas heat exchange in the air preheater 130, and the utilization effect of flue gas waste heat is further improved. Meanwhile, the humidified and heated air is introduced into the heating furnace for combustion, so that the content of NOx in the formed flue gas can be reduced.
In conclusion, the air is humidified by the micro interface contact and spray contact, so that the water vapor content of the combustion air entering the heating furnace is increased. Because the specific heat capacity of the water vapor is larger than that of the flue gas, the combustion temperature of the heating furnace can be effectively reduced by increasing the content of the water vapor; meanwhile, the content of the water vapor is increased to dilute the oxygen content in the air, so that the contact probability of nitrogen and oxygen is reduced, the generation amount of NOx in the combustion process is effectively reduced, and the content of the NOx in the flue gas can be reduced by more than 30%.
It should be noted that the air preheater 130 may be a plate type, a turbolator, a heat pipe type, a tube type, a split type, or a commercially available preheater such as the water heat medium air preheater 130.
Example 2
Referring to fig. 3, the present embodiment provides a heating furnace flue gas waste heat recovery system 200, which includes a spray cooling tower 210, the spray cooling tower 210 includes a cooling tower body 211, the cooling tower body 211 is provided with a cooling section 240 and a condensing section 250, the cooling section 240 is communicated with the condensing section 250, the cooling section 240 is relatively close to the tower bottom, the condensing section 250 is relatively close to the tower bottom, and meanwhile, one side of the cooling tower body 211 relatively close to the tower bottom is provided with a flue gas inlet 212, that is, the flue gas inlet 212 is located in the cooling section 240.
Further, a demister 216 is further disposed between the third spraying device 263 and the tower top of the cooling tower body 211.
The spray cooling tower 210 includes a baffle 215, and the arrangement of the baffle 215 is the same as that of the baffle 215 in embodiment 1.
Meanwhile, the liquid outlet of the cooling tower body 211, that is, the liquid outlet of the cooling section 240, is connected to the first spraying device 213, so that the liquid in the cooling section 240 can be recycled, but at this time, the liquid outlet of the cooling section 240 is not connected to the second spraying device 222, that is, the liquid in the cooling section 240 is not introduced into the air humidifying tower 220.
The condensing section 250 is located above the cooling section 240, i.e. relatively close to the top, so as to further recover the waste heat of the flue gas cooled by the cooling section 240.
Specifically, the spray cooling tower 210 further includes a condensing portion 260 for further condensing the flue gas, the condensing portion 260 is disposed in the cooling tower body 211 and connected to the cooling tower body 211, and the condensing portion 260 is located between the first spraying device 213 and the tower top of the cooling tower body 211; then, the flue gas is further subjected to waste heat recovery after being subjected to waste heat recovery by the first spraying device 213.
Further, the condensing part 260 includes a bottom plate 261, a flue gas riser 262 and a third spraying device 263, the bottom plate 261 is disposed between the first spraying device 213 and the top of the cooling tower body 211, the bottom plate 261 is fixedly connected to the cooling tower body 211, the flue gas riser 262 is disposed on the bottom plate 261 and connected to the bottom plate 261, and the third spraying device 263 is disposed between the bottom plate 261 and the top of the cooling tower body 211, so that the flue gas passes through the flue gas riser 262 and then contacts with condensate sprayed by the third spraying device 263, thereby further recovering waste heat in the flue gas, and meanwhile, the bottom plate 261 can accumulate the condensate sprayed by the third spraying device, i.e. form accumulated water of the condensing section 250.
Meanwhile, the bottom plate 261 is connected to the second spraying device 222, so that the liquid sprayed by the third spraying device 263 collected by the bottom plate 261 can be humidified and heated by the second spraying device 222.
Further, the liquid outlet of the air humidifier body 221 is connected with the third spraying device 263, so that the cooled liquid can further absorb the waste heat of the flue gas, and the recovery effect of the waste heat of the flue gas is further improved.
It should be noted that the embodiment of the present invention that the bottom plate 261 is connected to the second spraying device 222, the liquid outlet of the air humidification tower 220 is connected to the third spraying device 263, and the liquid outlet of the cooling section 240 is connected to the first spraying device 213 is a preferred embodiment, but the connection manner may be changed, for example, the liquid outlet of the cooling section 240 is connected to the second spraying section, or the liquid outlet of the air humidification tower 220 is connected to the first spraying device 213, and these combinations are also within the protection scope of the embodiment of the present invention.
And when the heating furnace flue gas waste heat recovery system 200 is in operation, the height of the liquid accumulated on the bottom plate 261 cannot exceed the gas outlet of the flue gas ascending pipe 262, that is, no liquid in the condensation section 250 can enter the cooling section 240 through the flue gas ascending pipe 262.
Further, the flue gas rising pipe 262 is a venturi tube, and the venturi tube is arranged to remove moisture in the flue gas passing through the cooling section 240 as much as possible, so as to ensure that liquid drops do not enter the condensation section.
Further, a demister is arranged between the third spraying device 263 and the top of the cooling tower body 211; this defroster can get rid of the steam in the flue gas, guarantees that the flue gas of emission satisfies the emission requirement.
The heating furnace flue gas waste heat recovery system 200 comprises an air humidifying tower 220, the structure of the air humidifying tower 220 is the same as that of the air humidifying tower provided in embodiment 1, and the air outlet of the air humidifying tower 220 is communicated with the air inlet of the spray heat exchanger 214.
The heating furnace flue gas waste heat recovery system 200 includes an air preheater 230, and the structure and connection relationship with other devices of the air preheater 230 are the same as those provided in embodiment 1.
It should be noted that the liquid transportation and the like according to the embodiment of the present invention are all connected by a pump, so as to realize the transportation of the liquid, and the spray head adopted by the spray device according to the embodiment of the present invention is a rotary nozzle or other existing nozzles, for example, the third spray device adopts a rotary hollow atomizing nozzle.
Referring to fig. 4, the present embodiment further provides a combustion system 300, which includes a heating furnace 310 and a heating furnace flue gas waste heat recovery system 200, wherein the heating furnace 310 is connected to the heating furnace flue gas waste heat recovery system 200, specifically, a flue gas outlet of the heating furnace 310 is communicated with the flue gas inlet 212 of the air preheater 230, and an air inlet of the heating furnace 310 is communicated with an air outlet of the air preheater 230.
If the combustion system 300 does not include an air preheater 230 (not shown), the flue gas outlet of the furnace is in direct communication with the flue gas inlet 212 of the spray cooling tower 210, and the air inlet of the furnace is in communication with the air outlet of the spray heat exchanger 214.
This embodiment still provides an above-mentioned heating furnace flue gas waste heat recovery system's working process:
(1) the high-temperature flue gas with the temperature of 250 ℃ flows out of the heating furnace and then enters the air preheater to heat the air with the temperature of 80 ℃ entering the air preheater, the temperature of the flue gas is reduced to 100 ℃ and then enters the spray cooling tower to heat the air with the temperature of 50 ℃ in the spray heat exchanger, meanwhile, the temperature of the flue gas sprayed by the first spraying device is 63 ℃ cooling water and is reduced to 64 ℃, the flue gas enters the condensation section through the flue gas ascending pipe, the flue gas is cooled to 54 ℃ by condensate liquid with the temperature of 52 ℃ sprayed by the third spraying device, and the flue gas enters the demister to remove supersaturated water and then is. Wherein the condensate sprayed by the third spraying device is circulated from the air humidifying tower.
(2) The normal temperature air at 20 ℃ is distributed into submicron-grade small bubbles by a micropore gas distributor, enters an air humidifying tower, fully contacts with circulating cooling water at 53 ℃ at the bottom of the tower for heat exchange, ascends to contact with fine liquid drops atomized by a second spraying device and an atomizer for mass transfer and heat transfer, reaches a 50 ℃ saturation state, is led out through a humidifying air outlet section of the air humidifying tower, enters a spraying heat exchanger, is heated to 80 ℃ by flue gas at 100 ℃ and cooling water sprayed by a first spraying device, enters an air preheater, further rises to 235 ℃, enters a heating furnace, and burns with fuel gas to release heat.
(3) And (3) pumping the 63-DEG C intermediate-temperature circulating water at the bottom of the cooling section of the spray cooling tower into a first spraying device by a pump, spraying cooling flue gas, heating and humidifying air by a spraying heat exchanger, and returning to the bottom of the cooling section for circulating spraying. 58 ℃ circulating cooling water at the bottom of a condensation section of the spray cooling tower enters the air humidifying tower through a pump, is sprayed out by the second spraying device, descends to the atomizer, is further cut and broken and then contacts with the ascending air for mass transfer and heat transfer, enters the tower bottom after the temperature is reduced by 53 ℃ and is accumulated, contacts with the submicron air generated by the microporous gas distributor for heat exchange, is further reduced to 52 ℃, is discharged from the bottom of the air humidifying tower through the pump and enters the spray cooling tower to be sprayed out by the third spraying device, contacts with the ascending 64 ℃ saturated flue gas for heat exchange, and is heated to 58 ℃ after condensing the flue gas and returns to the bottom of the condensation section, so that circulation is completed.
Compared with the heating furnace exhaust gas temperature of 100 ℃, the embodiment recovers more sensible heat of the flue gas at 46 ℃ and latent heat of condensation at 0.5 ℃, and can improve the comprehensive heat efficiency of the heating furnace by 3.5 percentage points; the NOx content in the smoke can be reduced by 35 percent compared with the prior art, and is as low as 65mg/m3And the energy-saving and emission-reducing effects are obvious.
Example 3
This embodiment still provides a process of utilizing heating furnace flue gas waste heat recovery system of embodiment 2 to retrieve flue gas waste heat, and the specific process is the same with the working process that embodiment 2 provided, and the difference lies in the temperature of the flue gas that adopts, the temperature of air and the temperature of different liquid are different, specifically as follows:
the temperature of the flue gas flowing out of the heating furnace is 280 ℃, and the temperature of the flue gas is reduced to 100 ℃ after passing through the air preheater; the temperature of the air entering the air preheater is 70 ℃; the air entering the heating spray heat exchanger is 50 ℃; the temperature of the flue gas after heat exchange of the first spraying device is 65 ℃; the temperature of cooling water sprayed by the first spraying device is 64 ℃; the temperature of condensate sprayed by the third spraying device is 52 ℃; the temperature of the flue gas after heat exchange of the third spraying device is 53 ℃.
The air introduced into the air humidifying tower is 0 ℃; the temperature of the water accumulated at the bottom of the air humidifying tower is 52 ℃; the air flowing out of the air humidifying tower is in a 50 ℃ saturated state; the flue gas and the liquid with the temperature of 64 ℃ are heated to 70 ℃ in a spray heat exchanger; heated to 270 ℃ by an air preheater.
The temperature of water accumulated in a cooling section of the spray cooling tower is 64 ℃, the temperature of water accumulated in a condensing section is 60 ℃, the temperature of the water accumulated in the condensing section is reduced to 53 ℃ after entering a second spray device of the air humidifying tower to act with upstream air, the temperature of the water is reduced to 52 ℃ after the water accumulated in the condensing section acts with gas formed by a micropore gas distributor, and the 52 ℃ water accumulated at the bottom of the air humidifying tower is pumped to a third spray device to act with upstream 65 ℃ saturated flue gas and is accumulated to the condensing section.
Compared with the heating furnace exhaust gas temperature of 100 ℃, the embodiment recovers the sensible heat of the flue gas at 47 ℃ and the latent heat of condensation at 1.5 ℃ more, and can improve the comprehensive heat efficiency of the heating furnace by 4.5 percentage points; the NOx content in the smoke can be reduced by 40 percent compared with the prior art, and is as low as 60mg/m3And the energy-saving and emission-reducing effects are obvious.
The embodiment of the invention provides a heating furnace waste heat recovery method, which utilizes the heating furnace flue gas waste heat recovery system for recovery, wherein the temperature of flue gas discharged from a heating furnace is more than or equal to 150 ℃, the temperature of flue gas discharged from an air preheater is 80-120 ℃, the temperature of flue gas discharged from a spray cooling tower is 50-60 ℃, the temperature of air introduced into an air humidifying tower is-20-40 ℃, the temperature of air discharged from the air humidifying tower is 40-55 ℃, and the temperature of air discharged from a spray heat exchanger is 70-90 ℃. And the mass fraction of the steam content of the combustion air entering the heating furnace is 0-20%, preferably 5-10%.
In conclusion, the heating furnace flue gas waste heat recovery system provided by the embodiment of the invention can recover 30-70 ℃ flue gas sensible heat and 0-5 ℃ condensation latent heat more, can improve the comprehensive heat efficiency of the heating furnace by 2-8 percentage points, and has an obvious energy-saving effect.
The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. The heating furnace flue gas waste heat recovery system is characterized by comprising a spray cooling tower and an air humidifying tower for forming heating and humidifying air, wherein the spray cooling tower is connected with the air humidifying tower;
the spray cooling tower comprises a cooling tower body and a first spray device for spraying cooling liquid, wherein a flue gas inlet is formed in one side, relatively close to the tower bottom, of the cooling tower body, the first spray device is arranged in the cooling tower body and is positioned at one side, relatively close to the tower top of the cooling tower body, so that convection is formed between the flue gas and the cooling liquid, then the flue gas heats the cooling liquid, and the waste heat of the flue gas is recovered;
the air humidifying tower comprises an air humidifier body and a second spraying device for spraying liquid, the second spraying device is arranged in the air humidifier body and is located on one side, close to the tower top relatively, of the air humidifier body, the liquid outlet of the cooling tower body is connected with the second spraying device, an air inlet is formed in one side, close to the tower bottom relatively, of the air humidifier body, convection of air and liquid is formed, liquid sprayed in the cooling tower body passes through the second spraying device, the air is heated and humidified, and the air humidifier body is provided with an air outlet for introducing gas of the heated and humidified air into the heating furnace.
2. The heating furnace flue gas waste heat recovery system according to claim 1, wherein the air humidifying tower further comprises a microporous gas distributor, the microporous gas distributor is arranged at the bottom of the tower inside the air humidifier body and connected with the air humidifier body, and the air inlet is communicated with the microporous gas distributor.
3. The heating furnace flue gas waste heat recovery system according to claim 2, wherein the microporous gas distributor is a membrane element;
preferably, a plurality of membrane tubes are arranged in the membrane element;
preferably, the equivalent diameter of the membrane tube is 10-70mm, the porosity of the membrane element is 50-80%, the pore diameter of the micropores of the membrane element is less than 1 μm, and the membrane on the membrane tube is a ceramic membrane or a hollow fiber membrane.
4. The heating furnace flue gas waste heat recovery system according to claim 2, wherein the air humidifying tower further comprises an atomizer, the atomizer is arranged in the air humidifier body and connected with the air humidifier body, and the atomizer is located between the second spraying device and the microporous gas distributor, so that the atomizer cuts the liquid sprayed by the second spraying device to form refined liquid drops.
5. The heating furnace flue gas waste heat recovery system according to claim 4, wherein the atomizer is a grid-type atomizer, the thickness of a grid is 5-30mm, and the equivalent diameter of grid holes is 0.1-10 mm;
preferably, the liquid outlet of the air humidifier body is connected with the first spraying device.
6. The heating furnace flue gas waste heat recovery system according to any one of claims 1 to 5, wherein the spray cooling tower further comprises a spray heat exchanger, the spray heat exchanger is arranged between the flue gas inlet and the first spray device, the spray heat exchanger is connected with the cooling tower body, and an air inlet of the spray heat exchanger is communicated with an air outlet of the air humidifier body.
7. The heating furnace flue gas waste heat recovery system according to claim 6, wherein the spray heat exchanger is a tubular heat exchanger;
preferably, the tubular heat exchanger is a twisted tube or a spoiler is arranged in the tubular heat exchanger;
preferably, the pipe diameter of the pipe heat exchanger is 10-70 mm;
preferably, the liquid outlet of the cooling tower body is connected with the first spraying device;
preferably, the spray cooling tower comprises a guide plate for guiding the flue gas, the guide plate is arranged in the cooling tower body and connected with the cooling tower body, and the guide plate is arranged opposite to the flue gas inlet;
preferably, the guide plate is of a fan-shaped structure, and the included angle between the guide plate and the tower wall of the cooling tower body is 30-60 degrees.
8. A heating furnace flue gas waste heat recovery system according to any one of claims 1 to 5, wherein the spray cooling tower further comprises a condensing part for condensing flue gas, the condensing part is arranged in the cooling tower body and connected with the cooling tower body, and the condensing part is positioned between the first spraying device and the top of the cooling tower body;
preferably, the condensing part comprises a bottom plate, a flue gas ascending pipe and a third spraying device, the bottom plate is arranged between the first spraying device and the top of the cooling tower body, the bottom plate is fixedly connected with the cooling tower body, the flue gas ascending pipe is arranged on the bottom plate and is connected with the bottom plate, and the third spraying device is arranged between the bottom plate and the top of the cooling tower body, so that the flue gas contacts condensate sprayed by the third spraying device after passing through the flue gas ascending pipe;
preferably, a demister is further arranged between the third spraying device and the tower top of the cooling tower body;
preferably, the bottom plate is connected with the second spraying device, so that the liquid sprayed by the third spraying device can humidify and heat air; the liquid outlet of the air humidifier body is connected with a third spraying device;
preferably, the flue gas riser is a venturi tube.
9. The heating furnace flue gas waste heat recovery system of claim 1, further comprising an air preheater, the air preheater being in communication with the air outlet of the air humidifying tower, the air preheater being in communication with the flue gas inlet.
10. A combustion system, characterized in that it comprises a heating furnace flue gas waste heat recovery system according to any one of claims 1 to 9.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2415244A (en) * | 2004-06-19 | 2005-12-21 | Alastair Robertson | Heat recovery from flue gas of a boiler |
| CN107559861A (en) * | 2017-09-08 | 2018-01-09 | 清华大学 | Three towers unification heat-exchange method and device based on the circulation of boiler exhaust gas condensate heat-carrying |
| CN108970370A (en) * | 2018-10-09 | 2018-12-11 | 杭州蕴泽环境科技有限公司 | It is a kind of low cost flue gas device for deep cleaning and its purification receive water eliminating white smoke technique |
| CN109268821A (en) * | 2018-10-15 | 2019-01-25 | 北京建筑大学 | Gas fired-boiler waste heat recovering and purifying system based on film humidification |
| CN208704000U (en) * | 2018-07-30 | 2019-04-05 | 清华大学 | A kind of residual heat from boiler fume recovery system based on gas-burning machine heat pump |
-
2020
- 2020-10-23 CN CN202011149334.7A patent/CN112229230B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2415244A (en) * | 2004-06-19 | 2005-12-21 | Alastair Robertson | Heat recovery from flue gas of a boiler |
| CN107559861A (en) * | 2017-09-08 | 2018-01-09 | 清华大学 | Three towers unification heat-exchange method and device based on the circulation of boiler exhaust gas condensate heat-carrying |
| CN208704000U (en) * | 2018-07-30 | 2019-04-05 | 清华大学 | A kind of residual heat from boiler fume recovery system based on gas-burning machine heat pump |
| CN108970370A (en) * | 2018-10-09 | 2018-12-11 | 杭州蕴泽环境科技有限公司 | It is a kind of low cost flue gas device for deep cleaning and its purification receive water eliminating white smoke technique |
| CN109268821A (en) * | 2018-10-15 | 2019-01-25 | 北京建筑大学 | Gas fired-boiler waste heat recovering and purifying system based on film humidification |
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