CN211585974U - Novel low temperature denitration device - Google Patents
Novel low temperature denitration device Download PDFInfo
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- CN211585974U CN211585974U CN201921369024.9U CN201921369024U CN211585974U CN 211585974 U CN211585974 U CN 211585974U CN 201921369024 U CN201921369024 U CN 201921369024U CN 211585974 U CN211585974 U CN 211585974U
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Abstract
The utility model provides a novel low temperature denitration device, including predryer, gas heater, liquid cooling hot air distributor, empty blender of ammonia, spout ammonia grid, denitration reactor, economic benefits and social benefits heat pipe exchanger, draught fan, chimney, hot-blast backward flow fan and combustion-supporting fan. The utility model discloses a heating section entry at gas heater sets up the predryer, avoid the condition that gas heater blockked up among the low temperature denitrification facility, through setting up liquid cooling hot air distributor, aperture through two gas burner of rapid adjustment changes the flue gas temperature, with the needs that adapt to low temperature denitration reaction optimum temperature, setting through economic benefits and social benefits heat pipe exchanger, solve low temperature denitrification facility tail gas waste heat recovery problem, and then the flue gas stream used heat after the usable denitration heats blast furnace gas and combustion-supporting air simultaneously, it produces two effects to realize a heat exchanger, the heat economy nature that improves low temperature denitrification facility greatly is low, make the flue gas stream gain of heat obtain reasonable recycle, the energy waste has been reduced.
Description
Technical Field
The invention relates to the field of flue gas treatment, in particular to a novel low-temperature denitration device.
Background
In the steel industry, sintering machines, shaft furnaces, coke ovens, cement kilns, lime kilns and the like in the water industry, wet desulfurization and low-temperature SCR denitration processes are generally adopted for desulfurization and denitration treatment due to the reasons of low flue gas temperature, large flue gas ash amount, easy catalyst poisoning caused by metal elements in flue gas and the like. Taking a sintering machine as an example, the specific flue gas treatment process is sintering machine → dust remover → main induced draft fan → wet desulphurization → (wet electric dust remover) → low-temperature denitration → booster fan → chimney. At present, the technical route has more engineering application performance and more obvious technical advantages, and is favored by more environment-friendly enterprises and owners.
However, the problems to be solved urgently exist, the problems exposed by low-temperature denitration are more, particularly, wet saturated flue gas after wet desulphurization contains more liquid drops and gypsum particles to cause surface blockage of a flue gas heat exchanger, the resistance of a booster fan is high when the flue gas runs for a long time, extra electric energy consumption is not caused, the currently generally adopted technology for fully and uniformly mixing hot air and the flue gas in the temperature rising section of the low-temperature denitration device is that a hot air furnace is arranged, high-temperature flue gas is generated by combustion of the hot air furnace to heat and denitrate original flue gas, the technical equipment is more, the occupied area is large, the mixing uniformity is difficult to guarantee, the flue gas temperature is totally increased by about 40 ℃ after final denitration reaction, huge energy waste is caused by directly discharging the flue gas into a chimney, the heat economy of the low-temperature denitration device is greatly reduced, the hot air generated by combustion, the system occupies a large area, has large system inertia and poor dynamic adjustment capability, and cannot be well adapted to the load change of the low-temperature denitration device.
Disclosure of Invention
The invention aims to provide a using method of a novel low-temperature denitration device, and solves the problems that a flue gas heat exchanger in the low-temperature denitration device is blocked, the low heat economy of the low-temperature denitration device is low, and huge energy waste is caused.
In order to achieve the above purpose, the invention provides the following technical scheme: a novel low-temperature denitration device comprises a predryer, a flue gas heat exchanger, a liquid-cooling hot air distributor, an ammonia-air mixer, an ammonia-spraying grid, a denitration reactor, a double-effect heat pipe heat exchanger, an induced draft fan, a chimney, a hot air backflow fan and a combustion-supporting fan;
the inlet of the pre-dryer is used for being connected with a wet desulphurization outlet, the outlet of the pre-dryer is connected with the heating section of the flue gas heat exchanger, the heating section of the flue gas heat exchanger is connected with the liquid-cooling hot air distributor, the inlet of the liquid-cooling hot air distributor is communicated with an ammonia water outlet, the outlet of the liquid-cooling hot air distributor is connected with the ammonia air mixer, the liquid-cooling hot air distributor gasifies the ammonia water and then sends the gasified ammonia water to the ammonia air mixer, the outlet of the ammonia air mixer is connected with an ammonia injection grid, high-temperature flue gas generated by the liquid-cooling hot air distributor is mixed with flue gas flow in the flue gas heat exchanger and then is introduced into the ammonia injection grid, and the flue gas flow is mixed with ammonia gas/water vapor through the ammonia injection;
the outlet of the ammonia spraying grid is connected with the denitration reactor, the outlet of the denitration reactor is connected with the cooling end of the flue gas heat exchanger, the outlet of the cooling end of the flue gas heat exchanger is connected with the double-effect heat pipe heat exchanger, the outlet of the double-effect heat pipe heat exchanger is connected with the induced draft fan, and the outlet of the induced draft fan is connected with the chimney;
the inlet of the backflow fan is connected with the cooling end of the flue gas heat exchanger, the outlet of the backflow fan is connected with the pre-dryer, and the backflow fan divides partial flue gas flow at the cooling end of the flue gas heat exchanger into the pre-dryer;
the outlet of the combustion-supporting fan is connected with the double-effect heat pipe exchanger, the combustion-supporting fan conveys combustion-supporting air into the double-effect heat pipe exchanger for heating, the double-effect heat pipe exchanger is connected with the blast furnace gas outlet, and the double-effect heat pipe exchanger heats the blast furnace gas and the combustion-supporting air;
preferably, the pre-dryer comprises a main pipe and seven groups of branch pipes connected to the left side and the right side of the main pipe, the windward side of each branch pipe is provided with at least four small holes, part of flue gas flow at the cooling end of the flue gas heat exchanger is ejected from the small holes through a return fan to be mixed with wet saturated flue gas flowing out of a wet desulphurization outlet, and the wet saturated flue gas is pre-dried.
Preferably, the flow speed of the flue gas flow in the small holes is 20m/s, and the distance between the small holes is 200 mm and 400 mm.
Preferably, the liquid cooling and hot air distributor comprises a central main pipe and gas burners arranged at two ends, the central main pipe is used as a combustion chamber of the gas burners, and the blast furnace gas and combustion-supporting air are heated by the double-effect heat pipe heat exchanger and then are sent to the burners for combustion;
one end of the central main pipe is connected with an ammonia water inlet connecting pipe, the ammonia water inlet connecting pipe is connected with an ammonia water outlet, the other end of the central main pipe is connected with an ammonia gas/steam outlet connecting pipe, the ammonia gas/steam outlet connecting pipe is connected with an ammonia-air mixer, and the combustion-supporting air is divided into one path to be mixed with ammonia gas/steam mixed gas evaporated by the liquid cooling hot air distributor in the ammonia-air mixer;
the high-temperature flue gas spraying pipe is divided into an upper layer and a lower layer, the upper layer and the lower layer are alternately arranged, the windward side of the high-temperature flue gas spraying pipe is provided with high-temperature flue gas spraying holes, and high-temperature flue gas generated by the gas burner is sprayed out from the high-temperature flue gas spraying holes to heat flue gas flow flowing out of the heating section of the flue gas heat exchanger.
Preferably, the projection distance of the high-temperature flue gas spray holes along the section of the central main pipe is 200-500mm, and the flow velocity of flue gas flow in the high-temperature flue gas spray holes is 20 m/s.
Preferably, the central main pipe comprises a plurality of spiral partition plates, an outer sleeve, an inner sleeve and a plurality of limit baffle plates, the spiral partition plates and the inner sleeve are welded in a sealing mode, the spiral partition plates and the outer sleeve are in clearance fit, the limit baffle plates are fixed on the inner wall of the outer sleeve, and the spiral partition plates are located between the two limit baffle plates.
Preferably, double-effect heat pipe exchanger's heat transfer part adopts the heat pipe component, double-effect heat pipe exchanger includes from last gas chamber, air chamber and the flue gas chamber that sets gradually extremely down, be provided with the dynamic seal baffle between flue gas chamber and air chamber, dynamic seal baffle and heat pipe component clearance fit, the dynamic seal baffle guarantees heat pipe component axial expansion, be provided with the static seal baffle between gas chamber and air chamber, static seal baffle and heat pipe component rigid connection, the absolute seal of gas chamber and air chamber is guaranteed to the static seal baffle.
Preferably, the heat pipe elements are vertically arranged in the double-effect heat pipe exchanger by adopting pipe boxes.
Preferably, three sections of finned tubes are arranged on the surface of the heat pipe element along the length direction, the three sections of finned tubes are respectively arranged in the gas chamber, the air chamber and the flue gas chamber, the finned tubes are H-shaped fins, and the effective fin lengths of the finned tubes are sequentially 4:3:7 in the gas chamber, the air chamber and the flue gas chamber.
A using method of a novel low-temperature denitration device comprises the following steps:
the method comprises the following steps: introducing a wet saturated flue gas flow of 50-60 ℃ after wet desulphurization into a pre-dryer through the suction action of a draught fan, dividing part of the flue gas flow at the cooling end of a flue gas heat exchanger into the pre-dryer by a backflow fan, spraying the flue gas flow from each small hole of the pre-dryer, mixing the sprayed hot flue gas flow with the wet saturated flue gas flow, heating the steam in the wet saturated flue gas flow to an overheat state, heating to 3-5 ℃, and finishing the drying of the wet saturated flue gas flow;
step two: the dried flue gas flow continuously flows into a heating section of a flue gas heat exchanger, the flue gas flow is further heated to 150-;
meanwhile, ammonia water flows between the outer sleeve and the inner sleeve through an ammonia water inlet pipe joint from an ammonia water outlet, the outer sleeve and the inner sleeve are cooled by an ammonia water solution, the ammonia water sequentially flows through the spiral partition plate and flows to the ammonia air mixer through an ammonia gas/water vapor outlet pipe joint, the ammonia gas/water vapor is mixed with air which is conveyed by the combustion fan and heated by the double-effect heat pipe heat exchanger, and the mixed ammonia gas/water vapor and hot air are sent into the ammonia spraying grid by the ammonia air mixer.
Step three: then the flue gas flows through an ammonia spraying grid to be mixed with ammonia gas/steam, the fully mixed flue gas enters a denitration reactor to complete denitration reaction, the denitrated flue gas flows through a cooling section of a flue gas heat exchanger to be cooled, the temperature of the flue gas flow is reduced to 90-105 ℃, and partial flue gas flow in the cooling section of the flue gas heat exchanger is sent into a preheater by a return fan.
Step four: then the flue gas flows through the double-effect heat pipe exchanger to continuously emit partial heat for heating cold blast furnace gas and cold air, specifically, the flue gas flow from the cooling section of the flue gas exchanger flows into a flue gas chamber, the air is pumped into the air chamber by a combustion fan, the high-temperature gas enters the gas chamber, heat exchange is carried out through a heat pipe element, the temperature of the flue gas flow is reduced to 87-102 ℃, the air and the blast furnace gas are heated to about 100 ℃, finally the flue gas flow is pumped out by an induced draft fan and is sent into a chimney for emission, and the blast furnace gas and the air heated by the double-effect heat pipe exchanger are sent into burners at two sides of the liquid cooling hot air distributor for combustion to.
The beneficial effects are that the technical scheme of this application possesses following technological effect:
1. according to the invention, the pre-dryer is arranged at the inlet of the heating section of the flue gas heat exchanger, the dryness of the wet saturated flue gas flow after wet desulphurization is improved by using the pre-dryer, so that the dryness of the flue gas flow entering the flue gas heat exchanger is improved, the flue gas is completely dried and does not contain liquid drops when entering the flue gas heat exchanger, thus the corrosion and blockage conditions of the flue gas heat exchanger can be effectively reduced, and the blockage risk of the flue gas heat exchanger is reduced.
2. According to the invention, the liquid cooling hot air distributor is arranged, the gas burners are directly arranged on the central main pipe, a long hot air flue is not provided, and when the flue gas volume of the flue gas flow is increased or decreased, the flue gas temperature can be changed by rapidly adjusting the opening degrees of the two gas burners so as to adapt to the requirement of the optimal temperature of low-temperature denitration reaction, reduce the thermal inertia of a hot air system and improve the load following capability of a denitration system.
3. The blast furnace gas belongs to low-heat value combustion, the heat value is usually less than 3500kJ/Nm, the combustion is difficult and the fire extinguishing risk exists, the invention preheats the blast furnace gas and combustion-supporting air by arranging the double-effect heat pipe heat exchanger, thus the ignition performance of the blast furnace gas can be improved, and the central main pipe of the liquid cooling hot air distributor is used as a combustion chamber of the gas burner, the heat load of the volume of a hearth is larger than that of the conventional gas burner, thus the blast furnace gas combustion is more favorable, the blast furnace gas combustion is more sufficient, and the combustion flame is more stable.
4. The central main pipe of the liquid-cooling hot air distributor is directly cooled through the ammonia water solution, meanwhile, the investment for independently arranging the ammonia water evaporation tank is reduced, the central main pipe is used as a combustion hearth of a combustor and is easy to be corroded by high-temperature flue gas, the central main pipe is made into a double-sleeve structure, the inner sleeve and the outer sleeve are cooled through the ammonia water solution, the temperature of the central main pipe can be ensured to be in a proper range, meanwhile, the ammonia water absorbs internal flame radiation heat when flowing between the inner sleeve and the outer sleeve and is vaporized into ammonia gas/steam mixed gas, the ammonia gas is mixed with air in an ammonia-air mixer and then can be directly sent into an ammonia spraying grid, the arrangement of the ammonia water evaporation tank can be reduced, and the equipment investment.
5. The tail gas waste heat recovery problem of the low-temperature denitration device is solved through the arrangement of the double-effect heat pipe heat exchanger, low-temperature denitration needs to heat low-temperature flue gas to a higher temperature for denitration reaction, the temperature of the flue gas after the reaction is about 40 ℃ higher than that of incoming flue gas, so that great energy waste is caused, the double-effect heat pipe heat exchanger is arranged at the tail part of the low-temperature denitration device, and blast furnace gas and combustion air can be simultaneously heated through the waste heat of the denitrated flue gas flow through the double-effect heat pipe heat exchanger, so that one heat exchanger can generate two functions.
It should be understood that all combinations of the foregoing concepts and additional concepts described in greater detail below can be considered as part of the inventive subject matter of this disclosure unless such concepts are mutually inconsistent.
The foregoing and other aspects, embodiments and features of the present teachings can be more fully understood from the following description taken in conjunction with the accompanying drawings. Additional aspects of the present invention, such as features and/or advantages of exemplary embodiments, will be apparent from the description which follows, or may be learned by practice of specific embodiments in accordance with the teachings of the present invention.
Drawings
The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. Embodiments of various aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a flow chart of a low-temperature denitration device and a schematic layout of a part of the device;
FIG. 2 is a diagram of a pre-dryer arrangement;
FIG. 3 is a schematic view of an upper high temperature flue gas nozzle connected to a central main pipe;
FIG. 4 is a schematic view of a lower-layer high-temperature flue gas nozzle connected with a central main pipe;
FIG. 5 is a detail view of the central main tube;
FIG. 6 is a view showing the inner sleeve, the outer sleeve and the spiral partition plate being assembled together;
FIG. 7 is a schematic diagram of a double effect heat pipe exchanger arrangement;
FIG. 8 is a schematic view of finned tube groupings on the surface of a heat pipe element;
in the figures, the meaning of the reference numerals is as follows:
1. a pre-dryer; 2. a flue gas heat exchanger; 3. liquid cooling and hot air distributor; 4. an ammonia-air mixer; 5. an ammonia injection grid; 6. a denitration reactor; 7. a double-effect heat pipe exchanger; 8. an induced draft fan; 9. a chimney; 10. a hot air reflux fan; 11. a combustion fan; 12. a wet desulfurization outlet; 13. an ammonia water outlet; 14. and (4) a blast furnace gas outlet.
Detailed Description
In order to better understand the technical content of the present invention, specific embodiments are described below with reference to the accompanying drawings.
In this disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. Embodiments of the present disclosure are not necessarily intended to include all aspects of the invention. It should be appreciated that the various concepts and embodiments described above, as well as those described in greater detail below, may be implemented in any of numerous ways, as the disclosed concepts and embodiments are not limited to any one implementation. In addition, some aspects of the present disclosure may be used alone, or in any suitable combination with other aspects of the present disclosure.
As shown in fig. 1, a novel low-temperature denitration device comprises a pre-dryer 1, a flue gas heat exchanger 2, a liquid cooling hot air distributor 3, an ammonia-air mixer 4, an ammonia injection grid 5, a denitration reactor 6, a double-effect heat pipe heat exchanger 7, an induced draft fan 8, a chimney 9, a hot air reflux fan 10 and a combustion fan 11.
An inlet of the pre-dryer 1 is used for being connected with a wet desulphurization outlet 12, flue gas flow after wet desulphurization enters the pre-dryer 1, an outlet of the pre-dryer 1 is connected with a heating section of the flue gas heat exchanger 2, the heating section of the flue gas heat exchanger 2 is connected with a liquid cooling hot air distributor 3, an inlet of the liquid cooling hot air distributor 3 is communicated with an ammonia water outlet 13, the ammonia water outlet is connected with a device for storing ammonia water, an outlet of the liquid cooling hot air distributor 3 is connected with an ammonia air mixer 4, the liquid cooling hot air distributor 3 gasifies the ammonia water and then sends the gasified ammonia water to the ammonia air mixer 4, an outlet of the ammonia air mixer 4 is connected with an ammonia injection grid 5, high-temperature flue gas generated by the liquid cooling hot air distributor 3 is mixed with the flue gas flow in the flue gas heat exchanger 2 and then is introduced into the ammonia injection grid 5, the flue gas flow is mixed with ammonia gas/water vapor through the ammonia, the gas burners 301 are directly installed on the central main pipe, a long hot air flue is not provided, and when the flue gas volume of the flue gas flow is increased or decreased, the flue gas temperature can be changed by rapidly adjusting the opening degrees of the two gas burners 301 so as to meet the requirement of the optimal temperature of the low-temperature denitration reaction, reduce the thermal inertia of a hot air system, and improve the load following capability of the denitration system.
The export of ammonia injection grid 5 links to each other with denitration reactor 6, and the export of denitration reactor 6 links to each other with 2 cooling ends of gas heater, and the export of 2 cooling ends of gas heater links to each other with double-effect heat pipe exchanger 7, and the export of double-effect heat pipe exchanger 7 links to each other with draught fan 8, and the export of draught fan 8 links to each other with chimney 9.
The import of return fan 10 is connected with gas heater 2's cooling end, return fan 10's export links to each other with predryer 1, return fan 10 shunts the partial flue gas stream of gas heater 2 cooling end to in predryer 1, set up predryer 1 through the heating section entry at gas heater 2, utilize predryer 1 to improve the dryness fraction of wet saturation flue gas stream behind the wet flue gas desulfurization, and then improve the flue gas stream dryness fraction that gets into gas heater 2, when guaranteeing to get into gas heater 2, the flue gas is all dry, do not contain the liquid drop, can effectively reduce gas heater 2 corrosion and the jam condition like this, reduce the risk that gas heater 2 blockked up.
An outlet of a combustion fan 11 is connected with the double-effect heat pipe exchanger 7, the combustion fan 11 conveys combustion air into the double-effect heat pipe exchanger 7 for heating, the double-effect heat pipe exchanger 7 is connected with a blast furnace gas outlet 14, the blast furnace gas outlet is connected with a device for generating a large amount of blast furnace gas, the double-effect heat pipe exchanger 7 heats the blast furnace gas and the combustion air, the blast furnace gas belongs to low-heat-value combustion, and the heat value is usually less than 3500kJ/Nm3The invention preheats the blast furnace gas and the combustion-supporting air by arranging the double-effect heat pipe exchanger 7, thus improving the ignition performance of the blast furnace gas, and the central main pipe of the liquid cooling hot air distributor 3 is used as the combustion chamber of the gas burner 301, so that the heat load of the hearth volume is larger than that of the conventional gas burner, thereby being more beneficial to the combustion of the blast furnace gas, leading the combustion of the blast furnace gas to be more sufficient and leading the combustion flame to be more stable.
As shown in fig. 2, further, in this embodiment, the pre-dryer 1 includes a main pipe and seven groups of branch pipes 101 connected to left and right sides of the main pipe, at least four small holes 102 are opened on a windward side of the branch pipes, and a part of flue gas flow at a cooling end of the flue gas heat exchanger 2 is ejected from the small holes 102 by the return fan 10 to be mixed with wet saturated flue gas flowing out of the wet desulfurization outlet 12, so as to pre-dry the wet saturated flue gas.
Further, in the present embodiment, the flow velocity of the flue gas flow in the small holes 102 is 20m/s, and the distance between the small holes is 300 mm.
As shown in fig. 3, in the present embodiment, the liquid-cooling hot air distributor 3 includes a central main pipe and gas burners 301 installed at two ends, the central main pipe is used as a combustion chamber of the gas burners 301, and the blast furnace gas and the combustion-supporting air are heated by the double-effect heat pipe exchanger 7 and then sent to the burners 301 for combustion.
One end of the central main pipe is connected with an ammonia water inlet connecting pipe 303, the ammonia water inlet connecting pipe 303 is connected with an ammonia water outlet 13, the other end of the central main pipe is connected with an ammonia gas/steam outlet connecting pipe 304, the ammonia gas/steam outlet connecting pipe 304 is connected with an ammonia air mixer 4, and combustion-supporting air is divided into one path to be mixed with ammonia gas/steam mixed gas evaporated from the liquid cooling hot air distributor 3 in the ammonia air mixer 4.
As shown in fig. 3 and 4, the two axial sides of the central main pipe are both communicated with the high-temperature flue gas spray pipes 305, the high-temperature flue gas spray pipes 305 are divided into an upper layer and a lower layer, the upper layer and the lower layer of high-temperature flue gas spray pipes 305 are alternately arranged, the windward side of the high-temperature flue gas spray pipes 305 is provided with high-temperature flue gas spray holes 302, and high-temperature flue gas generated by the gas burner 301 is sprayed out from the high-temperature flue gas spray holes 302 to heat flue gas flowing.
Further, in this embodiment, the projection distance of the high-temperature flue gas nozzle holes 302 along the section of the central main pipe is 400mm, and the flow velocity of the flue gas flow in the high-temperature flue gas nozzle holes 302 is 20 m/s.
As shown in fig. 5 and 6, further, in this embodiment, the central main pipe includes a plurality of spiral partition boards 306, an outer sleeve 307, an inner sleeve 308 and a plurality of limit baffles 309, the spiral partition boards 306 and the inner sleeve 308 are welded by seal welding, the spiral partition boards 306 and the outer sleeve 307 are in clearance fit, the limit baffles 309 are fixed on the inner wall of the outer sleeve 307, the spiral partition boards 306 are located between the two limit baffles 309, the central main pipe of the liquid-cooled hot air distributor 3 is directly cooled by an ammonia solution, and meanwhile, investment for separately arranging an ammonia evaporation tank is reduced, the central main pipe is used as a burner combustion chamber, is easily eroded by high-temperature flue gas, the central main pipe is made into a double-sleeve structure, the inner sleeve 308 and the outer sleeve 307 are cooled by the ammonia solution, so as to ensure that the temperature of the central main pipe is within a proper range, and at the same time, ammonia absorbs radiation heat of internal flame when flowing between the inner sleeve, can directly send into in the ammonia injection grid 5 after mixing with the air in empty blender 4 of ammonia, carry out the setting that can reduce the aqueous ammonia evaporating pot, reduce the equipment investment.
As shown in fig. 7, further, in this embodiment, a heat exchange component of the dual-effect heat pipe exchanger 7 employs a heat pipe element 701, the dual-effect heat pipe exchanger 7 includes a gas chamber 702, an air chamber 703 and a flue gas chamber 704 which are sequentially arranged from top to bottom, a dynamic seal partition 706 is arranged between the flue gas chamber 704 and the air chamber 703, the dynamic seal partition 706 is in clearance fit with the heat pipe element 701, the dynamic seal partition 706 ensures axial expansion of the heat pipe element 701, a static seal partition 705 is arranged between the gas chamber 703 and the air chamber 702, the static seal partition 705 is rigidly connected with the heat pipe element 701, the static seal partition 705 ensures absolute seal between the gas chamber 702 and the air chamber 703, by arranging the dual-effect heat pipe exchanger 7, the problem of tail gas waste heat recovery of the low-temperature denitration device is solved, low-temperature flue gas needs to be heated to a higher temperature for denitration reaction, the temperature of, this has caused very big energy waste, sets up a double-effect heat pipe heat exchanger 7 at low temperature denitrification facility's afterbody, and the flue gas stream waste heat after usable denitration through this double-effect heat pipe heat exchanger 7 heats blast furnace gas and combustion air simultaneously, realizes that a heat exchanger produces two effects.
Further, in the present embodiment, as shown in fig. 7, the heat pipe elements 701 are arranged vertically with the pipe box inside the double effect heat pipe exchanger 7.
As shown in fig. 8, further, in this embodiment, three segments of finned tubes are arranged on the surface of the heat pipe element 701 along the length direction, the three segments of finned tubes are respectively arranged in the gas chamber 702, the air chamber 703 and the flue gas chamber 704, the finned tubes are H-shaped fins, and the effective fin lengths of the finned tubes in the gas chamber 702, the air chamber 703 and the flue gas chamber 704 are in the ratio of 4:3:7 in sequence.
A use method of a novel low-temperature denitration device specifically comprises the following steps:
the method comprises the following steps: introducing the wet saturated flue gas flow of 50-60 ℃ after wet desulphurization into the pre-dryer 1 through the suction effect of the induced draft fan 8, shunting part of the flue gas flow at the cooling end of the flue gas heat exchanger 2 into the pre-dryer 1 by the backflow fan 10, spraying out the flue gas flow from each small hole of the pre-dryer 1, mixing the sprayed hot flue gas flow with the wet saturated flue gas flow, heating the water vapor in the wet saturated flue gas flow to an overheat state, heating the water vapor by 3-5 ℃, and finishing the drying of the wet saturated flue gas flow.
Step two: the dried flue gas flow continuously flows into the heating section of the flue gas heat exchanger 2, the flue gas flow is further heated to 150-.
Meanwhile, ammonia water flows between the outer sleeve 307 and the inner sleeve 308 from the ammonia water outlet 13 through the ammonia water inlet connecting pipe 303, the outer sleeve 307 and the inner sleeve 308 are cooled by the ammonia water solution, the ammonia water sequentially flows through the spiral partition 306 and flows to the ammonia air mixer 4 from the ammonia gas/water vapor outlet connecting pipe 304, the ammonia gas/water vapor is mixed with air which is conveyed by the combustion fan 11 and heated by the double-effect heat pipe heat exchanger 7, and the mixed ammonia gas/water vapor and hot air are conveyed into the ammonia injection grid 5 by the ammonia air mixer 4.
Step three: then the flue gas flows through an ammonia spraying grid 5 to be mixed with ammonia gas/steam, the flue gas enters a denitration reactor 6 after being fully mixed to complete denitration reaction, the flue gas flows through a cooling section of a flue gas heat exchanger 2 to be cooled after denitration, the temperature of the flue gas flow is reduced to 90-105 ℃, and partial flue gas flow in the cooling section of the flue gas heat exchanger 2 is sent into a preheater 1 by a return fan 10.
Step four: then the flue gas flows through the double-effect heat pipe exchanger 7 to continuously emit partial heat for heating cold blast furnace gas and cold air, specifically, the flue gas flow from the cooling section of the flue gas heat exchanger 2 flows into a flue gas chamber 704, the air is pumped into an air chamber 703 by a combustion fan 11, the high-temperature gas enters a gas chamber 702, heat exchange is carried out through a heat pipe element 701, the temperature of the flue gas flow is reduced to 87-102 ℃, the air and the blast furnace gas are heated to about 100 ℃, finally the flue gas flow is pumped out by an induced draft fan 8 and is sent into a chimney 9 to be discharged, and the blast furnace gas and the air heated by the double-effect heat pipe exchanger 7 are sent into burners 301 on two sides of the liquid cooling hot air distributor 3 to be combusted.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be determined by the appended claims.
Claims (9)
1. A novel low-temperature denitration device is characterized by comprising a pre-dryer (1), a flue gas heat exchanger (2), a liquid cooling and hot air distributor (3), an ammonia-air mixer (4), an ammonia spraying grid (5), a denitration reactor (6), a double-effect heat pipe heat exchanger (7), an induced draft fan (8), a chimney (9), a hot air reflux fan (10) and a combustion fan (11);
the inlet of the pre-dryer (1) is used for being connected with a wet desulphurization outlet (12), the outlet of the pre-dryer (1) is connected with the heating section of the flue gas heat exchanger (2), the heating section of the flue gas heat exchanger (2) is connected with the liquid cooling and hot air distributor (3), the inlet of the liquid cooling and hot air distributor (3) is communicated with an ammonia water outlet (13), the outlet of the liquid cooling and hot air distributor (3) is connected with the ammonia air mixer (4), and the outlet of the ammonia air mixer (4) is connected with the ammonia spraying grid (5);
the outlet of the ammonia spraying grid (5) is connected with the denitration reactor (6), the outlet of the denitration reactor (6) is connected with the cooling end of the flue gas heat exchanger (2), the outlet of the cooling end of the flue gas heat exchanger (2) is connected with the double-effect heat pipe heat exchanger (7), the outlet of the double-effect heat pipe heat exchanger (7) is connected with the induced draft fan (8), and the outlet of the induced draft fan (8) is connected with the chimney (9);
the inlet of the backflow fan (10) is connected with the cooling end of the flue gas heat exchanger (2), the outlet of the backflow fan (10) is connected with the pre-dryer (1), the outlet of the combustion fan (11) is connected with the double-effect heat pipe heat exchanger (7), and the double-effect heat pipe heat exchanger (7) is connected with the blast furnace gas outlet (14).
2. The novel low-temperature denitration device according to claim 1, wherein the pre-dryer (1) comprises a main pipe and seven groups of branch pipes (101) which are respectively connected with the left side and the right side of the main pipe, and the windward side of each branch pipe is provided with at least four small holes (102).
3. The novel low-temperature denitration device as claimed in claim 2, wherein the flow velocity of the flue gas flow in the small holes (102) is 20m/s, and the distance between the small holes is 200 mm and 400 mm.
4. The novel low-temperature denitration device as claimed in claim 1, wherein the liquid-cooling hot air distributor (3) comprises a central main pipe and gas burners (301) arranged at two ends of the central main pipe, the central main pipe is used as a combustion chamber of the gas burners (301), one end of the central main pipe is connected with an ammonia water inlet connecting pipe (303), the ammonia water inlet connecting pipe (303) is connected with an ammonia water outlet (13), the other end of the central main pipe is connected with an ammonia gas/steam outlet connecting pipe (304), and the ammonia gas/steam outlet connecting pipe (304) is connected with an ammonia-air mixer (4);
the high-temperature flue gas spray pipes (305) are communicated with two axial sides of the central main pipe, the high-temperature flue gas spray pipes (305) are divided into an upper layer and a lower layer, the upper layer and the lower layer of the high-temperature flue gas spray pipes (305) are alternately arranged, and high-temperature flue gas spray holes (302) are formed in the windward side of the high-temperature flue gas spray pipes (305).
5. The novel low-temperature denitration device as claimed in claim 4, wherein the projection distance of the high-temperature flue gas injection holes (302) along the section of the central main pipe is 200-500mm, and the flow velocity of the flue gas flow in the high-temperature flue gas injection holes (302) is 20 m/s.
6. The novel low-temperature denitration device according to claim 5, wherein the central main pipe comprises a plurality of spiral clapboards (306), an outer sleeve (307), an inner sleeve (308) and a plurality of limit baffles (309), the spiral clapboards (306) and the inner sleeve (308) are welded by sealing welding, the spiral clapboards (306) and the outer sleeve (307) are in clearance fit, the limit baffles (309) are fixed on the inner wall of the outer sleeve (307), and the spiral clapboards (306) are located between the two limit baffles (309).
7. The novel low-temperature denitration device as claimed in claim 6, wherein the heat exchange component of the double-effect heat pipe exchanger (7) adopts a heat pipe element (701), the double-effect heat pipe exchanger (7) comprises a gas chamber (702), an air chamber (703) and a flue gas chamber (704) which are arranged from top to bottom in sequence, a dynamic sealing clapboard (706) is arranged between the flue gas chamber (704) and the air chamber (703), the dynamic sealing partition plate (706) is in clearance fit with the heat pipe element (701), the dynamic sealing partition plate (706) ensures the axial expansion of the heat pipe element (701), a static seal clapboard (705) is arranged between the gas chamber (702) and the air chamber (703), the static sealing diaphragm (705) is rigidly connected with the heat pipe element (701), and the static sealing diaphragm (705) ensures that the gas chamber (702) and the air chamber (703) are absolutely sealed.
8. The novel low-temperature denitration device according to claim 7, wherein the heat pipe elements (701) are vertically arranged in the double-effect heat pipe exchanger (7) by using pipe boxes.
9. The novel low-temperature denitration device according to claim 8, characterized in that three sections of finned tubes are arranged on the surface of the heat pipe element (701) along the length direction, the three sections of finned tubes are respectively arranged in the gas chamber (702), the air chamber (703) and the flue gas chamber (704), the finned tubes are H-shaped fins, and the effective fin lengths of the finned tubes in the gas chamber (702), the air chamber (703) and the flue gas chamber (704) are sequentially in a ratio of 4:3: 7.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921369024.9U CN211585974U (en) | 2019-08-22 | 2019-08-22 | Novel low temperature denitration device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921369024.9U CN211585974U (en) | 2019-08-22 | 2019-08-22 | Novel low temperature denitration device |
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| CN211585974U true CN211585974U (en) | 2020-09-29 |
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| CN201921369024.9U Active CN211585974U (en) | 2019-08-22 | 2019-08-22 | Novel low temperature denitration device |
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| CN (1) | CN211585974U (en) |
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