CN114644349A - Denitration pyrolysis system utilizing pure flue gas for heating under full-load section - Google Patents
Denitration pyrolysis system utilizing pure flue gas for heating under full-load section Download PDFInfo
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- 238000000197 pyrolysis Methods 0.000 title claims abstract description 115
- 239000003546 flue gas Substances 0.000 title claims abstract description 86
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 85
- 238000010438 heat treatment Methods 0.000 title claims abstract description 56
- 239000004202 carbamide Substances 0.000 claims abstract description 71
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 69
- 239000000243 solution Substances 0.000 claims abstract description 51
- 238000010790 dilution Methods 0.000 claims abstract description 39
- 239000012895 dilution Substances 0.000 claims abstract description 39
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 33
- 239000007921 spray Substances 0.000 claims description 17
- 229910021529 ammonia Inorganic materials 0.000 claims description 10
- 230000002209 hydrophobic effect Effects 0.000 claims description 9
- 239000002351 wastewater Substances 0.000 claims description 9
- 238000011010 flushing procedure Methods 0.000 claims description 8
- 238000003860 storage Methods 0.000 claims description 8
- 238000010531 catalytic reduction reaction Methods 0.000 claims 1
- 239000007789 gas Substances 0.000 description 10
- 230000000694 effects Effects 0.000 description 9
- 238000012423 maintenance Methods 0.000 description 9
- 239000000779 smoke Substances 0.000 description 8
- 238000000034 method Methods 0.000 description 5
- 238000009826 distribution Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000000428 dust Substances 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000009991 scouring Methods 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000000889 atomisation Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/02—Preparation, purification or separation of ammonia
- C01C1/08—Preparation of ammonia from nitrogenous organic substances
- C01C1/086—Preparation of ammonia from nitrogenous organic substances from urea
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
- F28D7/08—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being otherwise bent, e.g. in a serpentine or zig-zag
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2062—Ammonia
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/02—Other waste gases
- B01D2258/0283—Flue gases
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- Environmental & Geological Engineering (AREA)
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- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Inorganic Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
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Abstract
The application provides a denitration pyrolysis system utilizing pure flue gas to heat under full load section, and relates to the technical field of flue gas denitration. The utility model provides an utilize denitration pyrolysis system of pure flue gas heating under full load section, includes cold wind dilution fan, boiler, heat exchanger and pyrolysis oven, and above-mentioned heat exchanger is located the flue of above-mentioned boiler, and the entrance point of above-mentioned heat exchanger passes through the pipe connection with above-mentioned cold wind dilution fan, and the exit end and the above-mentioned pyrolysis oven of above-mentioned heat exchanger are connected, and above-mentioned pyrolysis oven is connected with urea solution source system, and there is the ammonia gas blender bottom end of above-mentioned pyrolysis oven through the pipe connection. This application utilizes the heat of high temperature flue gas to heat cold wind, improves heat exchange efficiency, reduces calorific loss to cancel electric heater auxiliary heating, its system layout is simple, and the operation is maintained portably, and the equipment input is few.
Description
Technical Field
The application relates to the technical field of flue gas denitration, and particularly relates to a denitration pyrolysis system utilizing pure flue gas to heat under a full-load section.
Background
A flue gas heating denitration pyrolysis system commonly adopted in the industry at present is a mode of 'hot primary air + electric heater', the process flow is that an electric heater is connected in series at the outlet of a flue gas heater, the power of the electric heater is set to be about 1200kW-2400kW according to the difference of dilution air volume, the temperature of flue gas is lower at the initial starting stage of a unit, before grid connection and when the load is below 300MW, the urea pyrolysis temperature requirement cannot be met (the pyrolysis temperature is 400-.
Disclosure of Invention
An object of this application is to provide a denitration pyrolysis system who utilizes pure flue gas heating under full load section, its heat that can utilize high temperature flue gas heats cold wind, improves heat exchange efficiency, cancels electric heater boosting.
The embodiment of the application is realized as follows:
the utility model provides an utilize denitration pyrolysis system of pure flue gas heating under full load section, includes cold wind dilution fan, boiler, heat exchanger and pyrolysis oven, and above-mentioned heat exchanger is located the flue of above-mentioned boiler, and the entrance point of above-mentioned heat exchanger passes through the pipe connection with above-mentioned cold wind dilution fan, and the exit end and the above-mentioned pyrolysis oven of above-mentioned heat exchanger are connected, and above-mentioned pyrolysis oven is connected with urea solution source system, and there is the ammonia gas blender bottom end of above-mentioned pyrolysis oven through the pipe connection.
In some embodiments of the present application, the system further comprises an economizer, one end of the economizer is connected to the flue gas outlet end of the heat exchanger through a pipeline, and the other end of the economizer is connected to the SCR reactor through a pipeline.
In some embodiments of the present application, the ammonia mixer is connected to the SCR reactor by a pipe.
In some embodiments of the present application, a high temperature bypass is further included, and one end of the high temperature bypass is connected to the inlet end of the heat exchanger, and the other end of the high temperature bypass is connected to the outlet end of the heat exchanger.
In some embodiments of the present application, the urea solution source system includes a urea spray gun connected to the pyrolysis furnace, and a metering and distributing device is disposed on the urea spray gun and connected to a urea solution circulating device through a pipeline.
In some embodiments of this application, above-mentioned urea solution source system still includes compressed air storage tank, hydrophobic washing unit, valves and waste water discharge pipe, and above-mentioned compressed air storage tank passes through the tube coupling with above-mentioned urea spray gun and above-mentioned measurement distribution device respectively, and above-mentioned hydrophobic washing unit passes through the tube coupling with above-mentioned measurement distribution device, and above-mentioned valves passes through the tube coupling with above-mentioned measurement distribution device, above-mentioned urea solution circulating device and above-mentioned hydrophobic washing unit respectively, and above-mentioned waste water discharge pipe is connected with above-mentioned measurement distribution device.
In some embodiments of the present application, the height of the urea injection lance to the outlet flange of the pyrolysis furnace is 14-15 m.
In some embodiments of the present application, the inlet of the pyrolysis furnace is provided with a cyclone distributor, the cyclone distributor employs a cyclone plate, and the inclination angle of the cyclone plate is 28-32 °.
In some embodiments of the present application, the heat exchanger includes an outer tube and a plurality of mutually communicated cold air heating pipes installed inside the outer tube, a flue gas inlet is disposed at a top end of the outer tube, a flue gas outlet is disposed at a bottom end of the outer tube, a cold air inlet pipe is disposed on a top side wall of the outer tube, a cold air outlet pipe is disposed on a bottom side wall of the outer tube, the plurality of cold air heating pipes are all communicated with the cold air inlet pipe and the cold air outlet pipe, and a booster pump is connected to the cold air inlet pipe.
In some embodiments of the present application, a plurality of U-shaped pipes are disposed between two adjacent cold air heating pipes, and the plurality of U-shaped pipes are all communicated with the cold air heating pipes.
Compared with the prior art, the embodiment of the application has at least the following advantages or beneficial effects:
in this application embodiment, this denitration pyrolysis system includes cold wind dilution fan, boiler, heat exchanger and pyrolysis oven, moves the heat exchanger to the flue of boiler in, and heat exchanger one end is connected with cold wind dilution fan, and the other end is connected with the pyrolysis oven, and urea solution source system is connected to the pyrolysis oven side, and the ammonia blender is connected to the bottom. According to the method, a cold air dilution fan is adopted to replace hot primary air in a common flue gas denitration and pyrolysis process, cold air is changed into high-temperature dilution air after passing through a heat exchanger, and enters a pyrolysis furnace to be mixed with urea solution, so that the effect of hot air dilution for urea pyrolysis can be realized, leakage and inner wall attachments caused by scouring of the inner wall of a heat exchanger pipe due to large dust content in the hot primary air can be avoided, and the heat exchange efficiency is further greatly reduced; the heat exchanger is moved forwards into a flue of a boiler, the heat exchanger is connected with a cold air dilution fan, smoke passes through the outer side of a heat exchanger tube, the cold air passes through the inner side of the heat exchanger tube, the heat of high-temperature smoke is utilized to heat the cold air, the heat exchange efficiency is improved, the heat loss is reduced, the auxiliary heating of an electric heater is omitted, the equipment purchase cost of a large-scale electric heater, a transformer, a switch, a cable and the like is reduced, the load reduction even non-stop event caused by the fault of the electric heater is reduced, the equipment maintenance workload is reduced, the system arrangement is simple, the operation maintenance is simpler and more convenient, the equipment investment is less, the operation cost is low, the fault rate is low, no single large or small repair plan is required to be set, and the maintenance cost is saved.
In addition, a plurality of mutually communicated cold air heating pipes are arranged in the heat exchanger, two adjacent cold air heating pipes are communicated through a plurality of U-shaped pipes, on one hand, the cold air heating pipes and the inner sides of the U-shaped pipes can simultaneously contain cold air, the circulation quantity of the cold air is increased, and the heat exchange efficiency can be improved, on the other hand, the gas in the conventional heating pipes is in an S shape, the gas in the pipes can only flow in a single direction in such a way, the gas in the pipes can be heated to a higher temperature in the midway, so that the heat exchange effect of the cold air heating pipes positioned on the tail end side of the heat exchanger is poor, on the other hand, the cold air in the cold air heating pipes can flow in a multi-direction bending way by communicating the plurality of U-shaped pipes, on the one hand, the problem of poor heat exchange effect of the tail end of the heat exchanger can be solved, on the other hand, the temperature in the pipes can be more balanced by the multi-direction flowing cold air, so that the heat exchange efficiency of the cold air is improved, the heat loss of the flue gas is reduced.
When the flue gas denitration device is in actual operation, high-temperature flue gas enters a flue from a boiler and enters the inner side of an outer barrel of a heat exchanger, cold air is generated from a cold air dilution fan and enters a cold air inlet pipe through a pipeline, the cold air is pumped into a cold air heating pipe through a booster pump, the high-temperature flue gas heats cold air on the inner side of the cold air inlet pipe by utilizing the heat of the high-temperature flue gas to form high-temperature dilution air, the high-temperature dilution air enters a pyrolysis furnace through the pipeline, atomized urea solution is sprayed out of a urea solution source system and enters the pyrolysis furnace, the high-temperature dilution air and the atomized urea solution are fully mixed and then pyrolyzed to generate ammonia gas, the ammonia gas flows out of the bottom end of the pyrolysis furnace and enters an ammonia gas mixer through the pipeline, the ammonia gas then enters an SCR reactor, the flue gas flowing out of the heat exchanger passes through an economizer and then enters the SCR reactor to be subjected to a reverse reaction with the ammonia gas to be subjected to denitration.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required 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 application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.
FIG. 1 is a schematic flow diagram of a denitration pyrolysis system using pure flue gas heating in a full-load section according to the present application;
FIG. 2 is a schematic view of a urea solution source system of a denitration pyrolysis system using pure flue gas heating in a full load section according to the present application;
FIG. 3 is a schematic structural diagram of a heat exchanger of a denitration pyrolysis system heated by pure flue gas in a full-load section according to the present application;
fig. 4 is a schematic structural diagram of the inside of a heat exchanger of a denitration pyrolysis system heated by pure flue gas in a full-load section.
An icon: 1-a cold air dilution fan; 2-a heat exchanger; 21-an outer cylinder; 22-flue gas inlet; 23-a flue gas outlet; 24-a cold air heating pipe; a 25-U-shaped tube; 26-a cold air inlet pipe; 27-a booster pump; 28-a cold air outlet pipe; 3-a pyrolysis furnace; 4-a coal economizer; 5-urea solution source system; 51-a urea spray gun; 52-a metered dispensing device; 53-compressed air storage tank; 54-a hydrophobic washing device; 55-urea solution circulating device; 56-control valve group; 57-wastewater discharge pipe.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.
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 embodiments of the present application, it should be noted that if the terms "inside", "outside", etc. are used for indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings or the orientation or positional relationship which is usually arranged when the product of the application is used, the description is only for convenience of describing the application and simplifying the description, but the indication or suggestion that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, cannot be understood as the limitation of the application.
In the description of the embodiments of the present application, it should be further noted that unless otherwise explicitly stated or limited, the terms "disposed" and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
Example 1
Please refer to fig. 1, this embodiment provides a denitration pyrolysis system heated by pure flue gas under a full load section, which includes a cold air dilution fan 1, a boiler, a heat exchanger 2 and a pyrolysis furnace 3, wherein the heat exchanger 2 is located in a flue of the boiler, an inlet end of the heat exchanger 2 is connected to the cold air dilution fan 1 through a pipeline, an outlet end of the heat exchanger 2 is connected to the pyrolysis furnace 3, the pyrolysis furnace 3 is connected to a urea solution source system 5, and a bottom end of the pyrolysis furnace 3 is connected to an ammonia mixer through a pipeline.
In this embodiment, this denitration pyrolysis system includes that cold wind dilutes fan 1, boiler, heat exchanger 2 and pyrolysis oven 3, moves heat exchanger 2 to the flue of boiler in, 2 one ends of heat exchanger are connected with cold wind dilutes fan 1, and the other end is connected with pyrolysis oven 3, and urea solution source system 5 is connected to 3 sides of pyrolysis oven, and the ammonia mixer is connected to the bottom. According to the application, the cold air dilution fan 1 is adopted to replace hot primary air in the common flue gas denitration and pyrolysis process, cold air is changed into high-temperature dilution air after passing through the heat exchanger 2, and enters the pyrolysis furnace 3 to be mixed with the urea solution, so that the effect of hot air dilution for urea pyrolysis can be realized, leakage and inner wall attachments caused by scouring of the inner wall of the heat exchanger 2 due to large dust content in the hot primary air can be avoided, and the heat exchange efficiency is further greatly reduced; move heat exchanger 2 forward to the flue of boiler in, heat exchanger 2 is connected with cold wind dilution fan 1, the flue gas passes through the 2 intraductal sides of heat exchanger, cold wind is through 2 intraductal sides of heat exchanger, utilize the heat of high temperature flue gas to heat cold wind, improve heat exchange efficiency, reduce calorific loss, thereby cancel electric heater auxiliary heating, large-scale electric heater, the transformer, equipment purchasing cost such as switch and cable has been reduced, reduced because of electric heater trouble causes the load reduction even non-stop incident, spare parts purchasing cost has been reduced and the equipment maintenance work load has been reduced, its system layout is simple, the operation maintenance is more simple and convenient, the equipment input is few, the running cost is low, the fault rate is low, need not set up big alone, little maintenance plan, save the cost of overhaul.
In actual operation, high temperature flue gas gets into in the flue and through 2 outside of tubes of heat exchanger from the boiler, cold wind dilutes fan 1 production from cold wind, get into 2 inside of tubes of heat exchanger through the pipeline, high temperature flue gas utilizes its self heat to heat the inboard cold wind of geminate transistors and makes it become the dilution wind of high temperature, then get into in the pyrolysis oven 3, and during atomizing urea solution from the 5 blowout of urea solution source system and get into pyrolysis oven 3, the dilution wind of high temperature and the pyrolysis generation ammonia behind the atomizing urea solution intensive mixing, flow out and get into the ammonia mixer through the pipeline from 3 bottoms of pyrolysis oven.
Example 2
Referring to fig. 1, the embodiment provides a denitration pyrolysis system heated by pure flue gas in a full load section, which is different from the denitration pyrolysis system heated by pure flue gas in the full load section provided in embodiment 1 in that: the flue gas heat exchanger also comprises an economizer 4, wherein one end of the economizer 4 is connected with the flue gas outlet end of the heat exchanger 2 through a pipeline, and the other end of the economizer is connected with an SCR reactor through a pipeline.
In this embodiment, economizer 4 can further retrieve the waste heat of the high temperature flue gas behind heat exchanger 2, has reduced the exhaust gas temperature of flue gas, makes the flue gas rethread pipeline get into the SCR reactor and carries out the denitration.
Example 3
Referring to fig. 1, the embodiment provides a denitration pyrolysis system heated by pure flue gas in a full load section, which is different from the denitration pyrolysis system heated by pure flue gas in the full load section provided in embodiment 2 in that: the ammonia mixer is connected to the SCR reactor through a pipe.
In this embodiment, ammonia gas enters the SCR reactor from the ammonia gas mixer through the pipeline, and reacts with the flue gas as a reducing agent to reduce nitrogen oxides in the flue gas to N2Thereby realizing the denitration of the flue gas.
Example 4
Referring to fig. 1, the embodiment provides a denitration and pyrolysis system heated by pure flue gas in a full load section, which is different from the denitration and pyrolysis system heated by pure flue gas in a full load section provided in embodiment 3 in that: and one end of the high-temperature bypass is connected with the inlet end of the heat exchanger 2, and the other end of the high-temperature bypass is connected with the outlet end of the heat exchanger 2.
In this embodiment, the high temperature bypass is connected at 2 both ends of heat exchanger, and the cold wind that produces from cold wind dilution fan 1 can get into heat exchanger 2 and high temperature bypass simultaneously, then together get into pyrolysis oven 3 in, the high temperature bypass can be used to adjust the temperature of the high temperature dilution wind after the flue gas heating, avoids overtemperature damage equipment.
Example 5
Referring to fig. 1 and fig. 2, the embodiment provides a denitration and pyrolysis system heated by pure flue gas in a full load section, which is different from the denitration and pyrolysis system heated by pure flue gas in the full load section provided in embodiment 4 in that: the urea solution source system 5 includes a urea spray gun 51 connected to the pyrolysis furnace 3, the urea spray gun 51 is provided with a metering and distributing device 52, and the metering and distributing device 52 is connected to a urea solution circulating device 55 through a pipeline.
In this embodiment, the urea solution enters the metering and distributing device 52 through the urea solution circulating device 55, and the metering and distributing device 52 can control the flow rate and pressure of the urea solution, and then the urea solution is atomized in the urea spray gun 51 and enters the pyrolysis furnace 3.
Example 6
Referring to fig. 1 and fig. 2, the embodiment provides a denitration and pyrolysis system heated by pure flue gas in a full load section, which is different from the denitration and pyrolysis system heated by pure flue gas in a full load section provided in embodiment 5 in that: the urea solution source system 5 further includes a compressed air storage tank 53, a drain flushing device 54, a control valve set 56 and a waste water discharge pipe 57, wherein the compressed air storage tank 53 is connected to the urea spray gun 51 and the metering and distributing device 52 through pipelines, the drain flushing device 54 is connected to the metering and distributing device 52 through pipelines, the control valve set 56 is connected to the metering and distributing device 52, the urea solution circulating device 55 and the drain flushing device 54 through pipelines, and the waste water discharge pipe 57 is connected to the metering and distributing device 52.
In this embodiment, the compressed air enters the metering and distributing device 52 and the urea spray gun 51 through the compressed air storage tank 53, the compressed air does not react with the urea solution and can generate power to promote the atomization and injection of the urea solution, the hydrophobic flushing device 54 flushes the metering and distributing device 52 when the urea spray gun 51 is shut down, the urea solution can be prevented from being blocked by crystallization, the control valve set 56 can control the operation of the hydrophobic flushing device 54 and the urea solution circulating device 55, and the wastewater generated in the whole urea solution source system 5 is discharged through the wastewater discharge pipe 57.
Example 7
Referring to fig. 1 and fig. 2, the embodiment provides a denitration and pyrolysis system heated by pure flue gas in a full load section, which is different from the denitration and pyrolysis system heated by pure flue gas in a full load section provided in embodiment 6 in that: the height between the urea spray gun 51 and the outlet flange of the pyrolysis furnace 3 is 14-15 m.
In this embodiment, through increasing the height between urea spray gun 51 to the 3 outlet flanges of pyrolysis furnace, can make urea solution dwell time be not less than 8s in pyrolysis furnace 3, the height between urea spray gun 51 to the 3 outlet flanges of pyrolysis furnace is 10m in the ordinary denitration pyrolysis system, and urea solution dwell time is 5s in pyrolysis furnace 3, increases urea solution dwell time in pyrolysis furnace 3, can guarantee that urea solution is fully mixed and is dissolved in pyrolysis furnace 3.
Example 8
Referring to fig. 1, the embodiment provides a denitration pyrolysis system heated by pure flue gas in a full load section, which is different from the denitration pyrolysis system heated by pure flue gas in the full load section provided in embodiment 7 in that: the 3 entrances of above-mentioned pyrolysis oven are equipped with the cyclone distributor, above-mentioned cyclone distributor adopts the whirl board, and above-mentioned whirl board inclination is 28-32.
In this embodiment, whirl distributor adopts the perforated plate among the ordinary denitration pyrolysis system, changes the perforated plate into the whirl board that has certain inclination in this embodiment, can strengthen the rotatory rigidity of air current in the pyrolysis oven 3, stops to dilute the high urea solution that leads to of wind velocity of flow in the large size pyrolysis oven 3 and decomposes incompletely to block up the risk of 3 outlet pipe ways of pyrolysis oven after reducing the urea crystallization.
Example 9
Referring to fig. 1, the embodiment provides a denitration and pyrolysis system heated by pure flue gas in a full load section, which is different from the denitration and pyrolysis system heated by pure flue gas in a full load section provided in embodiment 8 in that: the heat exchanger 2 includes an outer cylinder 21 and a plurality of mutually communicated cold air heating pipes 24 installed inside the outer cylinder 21, a flue gas inlet 22 is provided at the top end of the outer cylinder 21, a flue gas outlet 23 is provided at the bottom end of the outer cylinder 21, a cold air inlet pipe 26 is provided on the sidewall of the top of the outer cylinder 21, a cold air outlet pipe 28 is provided on the sidewall of the bottom of the outer cylinder 21, the plurality of cold air heating pipes 24 are all communicated with the cold air inlet pipe 26 and the cold air outlet pipe 28, and a booster pump 27 is connected to the cold air inlet pipe 26.
In this embodiment, a smoke chamber is formed between the outer tube 21 of the heat exchanger 2 and the cold air heating pipe 24 installed inside the outer tube 21, high-temperature smoke enters through the smoke inlet 22, and is discharged from the smoke outlet 23, the cold air heating pipes 24 are communicated with each other, and the cold air heating pipes 24 are communicated with the cold air inlet pipe 26 and the cold air outlet pipe 28, the cold air inlet pipe 26 is connected with the cold air dilution fan 1 through a pipeline, the cold air outlet pipe 28 is connected with the pyrolysis furnace 3 through a pipeline, cold air generated from the cold air dilution fan 1 enters the cold air inlet pipe 26, and is pumped into the cold air heating pipes 24 through the booster pump 27, heat is applied to the cold air by using heat of the high-temperature smoke, the cold air heating pipes 24 which are communicated with each other can hold more cold air, and are heated at the same time, heat loss is reduced, and heat exchange efficiency is improved.
Example 10
Referring to fig. 1, the embodiment provides a denitration pyrolysis system heated by pure flue gas in a full load section, which is different from the denitration pyrolysis system heated by pure flue gas in the full load section provided in embodiment 9 in that: a plurality of U-shaped pipes 25 are provided between two adjacent cold air heating pipes 24, and the plurality of U-shaped pipes 25 are communicated with the cold air heating pipes 24.
In the present embodiment, two adjacent cold-air heating pipes 24 are communicated with each other through a U-shaped pipe 25, which, on one hand, so that the cold air can be contained in the cold air heating pipe 24 and the U-shaped pipe 25 at the same time, the circulation amount of the cold air is increased, the heat exchange efficiency is improved, on the other hand, the gas in the conventional heating pipe is S-shaped, in this way, the gas in the pipe can only flow in one direction, and the gas in the pipe can be heated to a higher temperature in the midway, so that the heat exchange effect of the cold air heating pipe 24 positioned at the tail end side of the heat exchanger 2 is deteriorated, and this embodiment communicates cold air heating pipe 24 through a plurality of U-shaped pipes 25, and cold air in the cold air heating pipe 24 can multidirectional crooked flow, can solve the not good problem of 2 tail end heat transfer effects of heat exchanger on the one hand, and on the other hand can multidirectional cold wind that flows make intraductal temperature more balanced to cold air carries out the efficiency of heat exchange has been improved.
In conclusion, the embodiment of this application provides a denitration pyrolysis system that utilizes pure flue gas heating under full load section, has following beneficial effect:
in this application embodiment, this denitration pyrolysis system includes cold wind dilution fan 1, boiler, heat exchanger 2 and pyrolysis oven 3, moves heat exchanger 2 to the flue of boiler in, and 2 one ends of heat exchanger are connected with cold wind dilution fan 1, and the other end is connected with pyrolysis oven 3, and urea solution source system 5 is connected to 3 sides of pyrolysis oven, and the ammonia mixer is connected to the bottom. According to the application, the cold air dilution fan 1 is adopted to replace hot primary air in the common flue gas denitration and pyrolysis process, cold air is changed into high-temperature dilution air after passing through the heat exchanger 2, and enters the pyrolysis furnace 3 to be mixed with the urea solution, so that the effect of hot air dilution for urea pyrolysis can be realized, leakage and inner wall attachments caused by scouring of the inner wall of the heat exchanger 2 due to large dust content in the hot primary air can be avoided, and the heat exchange efficiency is further greatly reduced; move heat exchanger 2 forward to the flue of boiler in, heat exchanger 2 is connected with cold wind dilution fan 1, the flue gas passes through the 2 intraductal sides of heat exchanger, cold wind is through 2 intraductal sides of heat exchanger, utilize the heat of high temperature flue gas to heat cold wind, improve heat exchange efficiency, reduce calorific loss, thereby cancel electric heater auxiliary heating, large-scale electric heater, the transformer, equipment purchasing cost such as switch and cable has been reduced, reduced because of electric heater trouble causes the load reduction even non-stop incident, spare parts purchasing cost has been reduced and the equipment maintenance work load has been reduced, its system layout is simple, the operation maintenance is more simple and convenient, the equipment input is few, the running cost is low, the fault rate is low, need not set up big alone, little maintenance plan, save the cost of overhaul.
In addition, a plurality of mutually communicated cold air heating pipes 24 are arranged in the heat exchanger 2 of the present application, and two adjacent cold air heating pipes 24 are communicated through a plurality of U-shaped pipes 25, on one hand, the inner sides of the cold air heating pipes 24 and the U-shaped pipes 25 can simultaneously contain cold air, so that the circulation amount of the cold air is increased, and the heat exchange efficiency can be improved, on the other hand, the gas in the conventional heating pipes is in an S shape, so that the gas in the pipes can only flow in one direction, the gas in the pipes can be heated to a higher temperature in the midway, and the heat exchange effect of the cold air heating pipes 24 positioned at the tail end side of the heat exchanger 2 is poor, on the other hand, the cold air in the pipes can flow more uniformly through the plurality of U-shaped pipes 25, and the cold air in the cold air heating pipes 24 can flow in a multi-direction bending manner, on the one hand, the problem of poor heat exchange effect at the tail end of the heat exchanger 2 can be solved, on the other hand, the multi-direction flowing cold air can make the pipe inner temperature more uniform, thereby improving the heat exchange efficiency of the cold air and reducing the heat loss of the smoke.
In actual operation, high-temperature flue gas enters a flue from a boiler and enters the inner side of the outer cylinder 21 of the heat exchanger 2, cold air is generated from the cold air dilution fan 1, enters the cold air inlet pipe 26 through a pipeline and is pumped into the cold air heating pipe 24 through the booster pump 27, the high-temperature flue gas heats cold air at the inner side of the cold air inlet pipe 26 by utilizing the heat of the high-temperature flue gas to become high-temperature dilution air, then enters the pyrolysis furnace 3 through a pipeline, atomized urea solution is sprayed out from the urea solution source system 5 and enters the pyrolysis furnace 3, the high-temperature dilution air and the atomized urea solution are fully mixed and then pyrolyzed to generate ammonia gas, the ammonia gas flows out of the bottom end of the pyrolysis furnace 3 and enters the ammonia gas mixer through a pipeline, then enters the SCR reactor, the flue gas flowing out of the heat exchanger 2 passes through the economizer 4 and then enters the SCR reactor to react with the ammonia gas to perform denitration.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (10)
1. The utility model provides an utilize denitration pyrolysis system of pure flue gas heating under full load section, its characterized in that, includes cold wind dilution fan, boiler, heat exchanger and pyrolysis oven, the heat exchanger is located in the flue of boiler, the entrance point of heat exchanger with cold wind dilution fan passes through the pipe connection, the exit end of heat exchanger with the pyrolysis oven is connected, the pyrolysis oven is connected with urea solution source system, just there is the ammonia blender pyrolysis oven bottom through the pipe connection.
2. The denitration pyrolysis system utilizing pure flue gas to heat under the full-load section according to claim 1, further comprising an economizer, wherein one end of the economizer is connected with the flue gas outlet end of the heat exchanger through a pipeline, and the other end of the economizer is connected with an SCR (selective catalytic reduction) reactor through a pipeline.
3. The denitration pyrolysis system heated by pure flue gas in the full load section of claim 2, wherein the ammonia mixer is connected to the SCR reactor through a pipeline.
4. The denitration pyrolysis system utilizing pure flue gas to heat under the full-load section according to claim 1, further comprising a high-temperature bypass, wherein one end of the high-temperature bypass is connected with the inlet end of the heat exchanger, and the other end of the high-temperature bypass is connected with the outlet end of the heat exchanger.
5. The denitration and pyrolysis system utilizing pure flue gas to heat under the full-load section according to claim 1, wherein the urea solution source system comprises a urea spray gun connected with the pyrolysis furnace, a metering and distributing device is arranged on the urea spray gun, and the metering and distributing device is connected with a urea solution circulating device through a pipeline.
6. The denitration pyrolysis system utilizing pure flue gas heating in a full load section of claim 5, wherein the urea solution source system further comprises a compressed air storage tank, a hydrophobic flushing device, a control valve set and a wastewater discharge pipe, wherein the compressed air storage tank is respectively connected with the urea spray gun and the metering and distributing device through pipelines, the hydrophobic flushing device is connected with the metering and distributing device through pipelines, the control valve set is respectively connected with the metering and distributing device, the urea solution circulating device and the hydrophobic flushing device through pipelines, and the wastewater discharge pipe is connected with the metering and distributing device.
7. The denitration pyrolysis system utilizing pure flue gas heating in a full load section of claim 5, wherein the height between the urea spray gun and the outlet flange of the pyrolysis furnace is 14-15 m.
8. The denitration and pyrolysis system utilizing pure flue gas heating in a full-load section according to claim 1, wherein a cyclone distributor is arranged at an inlet of the pyrolysis furnace, the cyclone distributor adopts a cyclone plate, and the inclination angle of the cyclone plate is 28-32 degrees.
9. The denitration and pyrolysis system utilizing pure flue gas to heat under the full-load section as claimed in claim 1, wherein the heat exchanger comprises an outer cylinder and a plurality of mutually communicated cold air heating pipes arranged inside the outer cylinder, a flue gas inlet is arranged at the top end of the outer cylinder, a flue gas outlet is arranged at the bottom end of the outer cylinder, a cold air inlet pipe is arranged on the top side wall of the outer cylinder, a cold air outlet pipe is arranged on the bottom side wall of the outer cylinder, the plurality of cold air heating pipes are all communicated with the cold air inlet pipe and the cold air outlet pipe, and a booster pump is connected to the cold air inlet pipe.
10. The denitration and pyrolysis system utilizing pure flue gas to heat under the full-load section according to claim 9, wherein a plurality of U-shaped pipes are arranged between two adjacent cold air heating pipes, and the plurality of U-shaped pipes are communicated with the cold air heating pipes.
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