CN113883544A - Sulfur-containing flue gas waste heat recovery device and control method - Google Patents
Sulfur-containing flue gas waste heat recovery device and control method Download PDFInfo
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- CN113883544A CN113883544A CN202111158391.6A CN202111158391A CN113883544A CN 113883544 A CN113883544 A CN 113883544A CN 202111158391 A CN202111158391 A CN 202111158391A CN 113883544 A CN113883544 A CN 113883544A
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- 239000003546 flue gas Substances 0.000 title claims abstract description 226
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 207
- 239000002918 waste heat Substances 0.000 title claims abstract description 38
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 title claims abstract description 30
- 229910052717 sulfur Inorganic materials 0.000 title claims abstract description 30
- 239000011593 sulfur Substances 0.000 title claims abstract description 30
- 238000011084 recovery Methods 0.000 title claims abstract description 24
- 238000000034 method Methods 0.000 title claims abstract description 16
- 238000012806 monitoring device Methods 0.000 claims abstract description 90
- 239000002253 acid Substances 0.000 claims abstract description 50
- 239000000779 smoke Substances 0.000 claims description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 32
- 238000006243 chemical reaction Methods 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 10
- 238000004321 preservation Methods 0.000 claims description 7
- 238000004134 energy conservation Methods 0.000 claims description 4
- 230000001174 ascending effect Effects 0.000 claims description 2
- 239000005864 Sulphur Substances 0.000 claims 1
- 238000005260 corrosion Methods 0.000 abstract description 10
- 230000007797 corrosion Effects 0.000 abstract description 10
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 24
- 230000008676 import Effects 0.000 description 7
- 230000002035 prolonged effect Effects 0.000 description 4
- 238000012544 monitoring process Methods 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 239000003245 coal Substances 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 101100391182 Dictyostelium discoideum forI gene Proteins 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/06—Arrangements of devices for treating smoke or fumes of coolers
-
- 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
- F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
- F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
-
- 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
- F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
- F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
- F28D15/06—Control arrangements therefor
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/30—Technologies for a more efficient combustion or heat usage
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Control Of Steam Boilers And Waste-Gas Boilers (AREA)
Abstract
The invention discloses a sulfur-containing flue gas waste heat recovery device and a control method, relates to the technical field of sulfur-containing flue gas treatment, and comprises a flue gas heat exchange device and an SO2A concentration monitoring device and a control terminal; the flue gas heat exchange device is used for being connected with a boiler flue and can exchange heat with flue gas in the boiler flue, and is provided with a medium inlet pipe and a medium outlet pipe which are respectively used for the inflow and outflow of heat exchange media and a flow control device which is used for controlling the flow of the heat exchange media in the flue gas heat exchange device; SO (SO)2The concentration monitoring device is arranged in the flue between the boiler flue inlet and the flue gas heat exchange device and is electrically connected with the control terminal; the control terminal can be according to SO2SO measured by concentration monitoring device2Calculating concentration to obtain acid dew point temperature, and controlling flow control device to make heat exchangedThe flue gas temperature is higher than the acid dew point temperature. The invention can recycle the waste heat in the sulfur-containing flue gas and simultaneously avoid equipment corrosion.
Description
Technical Field
The invention relates to the technical field of sulfur-containing flue gas treatment, in particular to a sulfur-containing flue gas waste heat recovery device and a control method.
Background
Fuels such as coal, oil and natural gas used by boilers contain certain sulfur, SO that flue gas generated by fuel combustion contains certain amount of SO as well as certain amount of water vapor2SO formed after combustion2A part of the oxygen is further oxidized into SO3And the sulfuric acid vapor is combined with the water vapor in the flue gas, and the condensation temperature of the sulfuric acid vapor in the flue gas is called as the acid dew point of the flue gas. When the temperature of the heated surface at the tail of the boiler is lower than the acid dew point of the flue gas, sulfuric acid vapor is condensed on the surface of the heated surface to form a sulfuric acid solution, and low-temperature corrosion is generated. At present, in the existing sulfur-containing flue gas waste heat recovery device in the industry, under different operating conditions of a chemical plant, the acid dew point temperature of flue gas is along with SO in the flue gas2The content of the SO in the flue gas can be changed at any time according to different contents2The difference of content adjusts the gas outlet temperature among the waste heat recovery system, makes the temperature of boiler afterbody heating surface be higher than the acid dew point of flue gas all the time, avoids heat exchanger acid corrosion the problem that needs to solve at present urgently.
Disclosure of Invention
The invention aims to provide a sulfur-containing flue gas waste heat recovery device and a control method, which are used for solving the problems in the prior art, can recycle waste heat in sulfur-containing flue gas and simultaneously avoid equipment corrosion.
In order to achieve the purpose, the invention provides the following scheme:
the invention provides a sulfur-containing flue gas waste heat recovery device, which comprises a flue gas heat exchange device and SO2A concentration monitoring device and a control terminal;
the flue gas heat exchange device is used for being connected with a boiler flue and can exchange heat with flue gas in the boiler flue, and a medium inlet pipe and a medium outlet pipe which are respectively used for the inflow and outflow of heat exchange media and a flow control device which is used for controlling the flow of the heat exchange media in the flue gas heat exchange device are arranged on the flue gas heat exchange device;
the SO2The concentration monitoring device is arranged in a flue between a boiler flue inlet and the flue gas heat exchange device and is electrically connected with the control terminal;
the control terminal can be according to the SO2SO measured by concentration monitoring device2And calculating the concentration to obtain the acid dew point temperature, and controlling the flow control device to enable the temperature of the flue gas after heat exchange to be higher than the acid dew point temperature.
Preferably, the flue gas heat exchange device comprises a phase-change heat exchanger, a phase-change heat exchange steam drum and a heat exchange coil, the phase-change heat exchanger is arranged in a flue between an inlet and an outlet of a flue of the boiler, the inlet and the outlet of the phase-change heat exchanger are respectively communicated with the inside of the phase-change heat exchange steam drum through a descending pipe and an ascending pipe, the heat exchange coil is arranged in the phase-change heat exchange steam drum, and two ends of the heat exchange coil are respectively communicated with the medium inlet pipe and the medium outlet pipe.
Preferably, the phase change heat exchanger is a spiral finned tube heat exchanger, and the heat exchange coil is a snakelike heat exchange coil.
Preferably, the system also comprises a water vapor concentration monitoring device and a flue gas pressure monitoring device, wherein the water vapor concentration monitoring device and the flue gas pressure monitoring device are arranged at the inlet of the boiler flue and in the flue between the flue gas heat exchange devices and are electrically connected with the control terminal.
Preferably, the SO2The concentration monitoring device comprises SO2The concentration sensor, the vapor concentration monitoring device comprises a flue gas moisture meter, the flue gas pressure monitoring device comprises a flue gas pressure sensor, and the SO2The concentration sensor, the smoke moisture meter and the smoke pressure sensor are all electrically connected with the control terminal.
Preferably, the flow control device comprises a flow control valve which is arranged on the medium inlet pipe and is electrically connected with the control terminal.
Preferably, the system also comprises an inlet smoke temperature monitoring device, wherein the inlet smoke temperature monitoring device is arranged in the flue between the boiler flue inlet and the smoke heat exchange device; an inlet medium temperature monitoring device is arranged on the medium inlet pipe, and an outlet medium temperature monitoring device is arranged on the medium outlet pipe; the inlet smoke temperature monitoring device, the inlet medium temperature monitoring device and the outlet medium temperature monitoring device are all electrically connected with the control terminal.
Preferably, the inlet flue gas temperature monitoring device comprises an inlet flue gas temperature sensor, the inlet medium temperature monitoring device comprises an inlet medium temperature sensor, the outlet medium temperature monitoring device comprises an outlet medium temperature sensor, and the inlet flue gas temperature sensor, the inlet medium temperature sensor and the outlet medium temperature sensor are electrically connected with the control terminal.
The invention also provides a waste heat recovery control method based on the sulfur-containing flue gas waste heat recovery device, which comprises the following steps:
s1: the SO2SO of boiler flue inlet is monitored in real time to concentration monitoring device2Volume fraction and transmitting to the control terminal;
s2: the control terminal measures SO according to S12Calculating the volume fraction to obtain SO in the flue gas3Volume fraction of (a);
s3: the control terminal controls the control terminal according to SO in S23Calculating the volume fraction of the flue gas to obtain the acid dew point temperature of the flue gas;
s4: and ensuring that the temperature of the low-temperature heating surface of the boiler is higher than the acid dew point t ℃ of the flue gas, namely the temperature of the flue gas outlet is higher than the acid dew point t ℃ of the flue gas, wherein t is more than 0, and the control terminal controls the flow control device to ensure that the temperature of the flue gas after heat exchange is higher than the acid dew point temperature.
Preferably, the steam concentration monitoring device, the inlet flue gas temperature monitoring device and the flue gas pressure monitoring device monitor the volume fraction of steam at the inlet of the boiler flue, the inlet flue gas temperature and the inlet flue gas pressure in real time and transmit the steam to the control terminal, and the inlet medium temperature monitoring device and the outlet medium temperature monitoring device monitor the inlet medium temperature and the outlet medium temperature of the flue gas heat exchange device in real time and transmit the steam to the control terminal;
selecting SO according to type of boiler2With SO3The conversion of (b) is then:
in formula (1):
η：SO2with SO3The conversion of (a);
the control terminal calculates according to the formula (1) to obtain SO in the flue gas3Volume fraction of (a);
if SO3Is higher than 35ppm, according to the formula h.a. bapahba:
if SO3In a volume fraction of not more than 35ppm, according to Haase&The Borgmann formula is:
wherein,
formula (2) to formula (5):
tadp: acid dew point temperature;
p0: inlet flue gas pressure;
the control terminal calculates according to the formula (2) to the formula (5) to obtain the acid dew point temperature;
ensuring that the temperature of the flue gas outlet is higher than the acid dew point t ℃ of the flue gas, and according to the law of energy conservation, the method comprises the following steps:
in formula (6):
K0: the heat exchange efficiency of the flue gas heat exchange device is improved;
K1: the heat preservation efficiency of the heat exchange equipment is improved;
t1: inlet flue gas temperature;
Δ t: the temperature difference between the outlet medium temperature and the inlet medium temperature of the flue gas heat exchange device;
the control terminal calculates the mass flow of the heat exchange medium according to the formula (6):
the control terminal controls the flow control device to ensure that the mass flow of the heat exchange medium of the flue gas heat exchange device is controlled
Compared with the prior art, the invention has the following technical effects:
the invention provides a sulfur-containing flue gas waste heat recovery device and a control method thereof, wherein SO is determined according to the type of a boiler2With SO3Conversion of (2) from SO2SO of boiler flue inlet is monitored in real time to concentration monitoring device2Volume fraction and transmitting to control terminal according to SO2Volume fraction and conversion rate, and control terminal calculating to obtain SO3In terms of SO, and3the volume fraction of the flue gas is calculated to obtain the acid dew point temperature, then the temperature of the low-temperature heating surface of the boiler is ensured to be higher than the acid dew point temperature of the flue gas and higher than the acid dew point t DEG C of the flue gas, namely the temperature of the flue gas outlet is higher than the acid dew point t DEG C of the flue gas, the control terminal controls the flow control device, heat exchange is carried out through the heat exchange medium and the flue gas, and partial heat in the flue gas is transferredAnd the flue gas waste heat is recycled in the heat exchange medium, and the flue gas temperature after heat exchange, namely the temperature of a flue gas outlet, is always higher than the acid dew point temperature, so that the sulfuric acid vapor is prevented from being condensed into a sulfuric acid solution, the equipment is prevented from being corroded, and the service life of the equipment is prolonged.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic structural diagram of a device for recovering waste heat from sulfur-containing flue gas provided by the invention;
FIG. 2 is a schematic view of structural connection between a phase-change heat exchange steam drum and a heat exchange coil in the device for recovering waste heat from sulfur-containing flue gas provided by the invention;
FIG. 3 is a schematic structural diagram of a phase change heat exchanger in the device for recovering waste heat of sulfur-containing flue gas provided by the invention;
in the figure: 100-sulfur-containing flue gas waste heat recovery device, 1-flue gas heat exchange device and 2-SO2The system comprises a concentration monitoring device, a 3-steam concentration monitoring device, a 4-inlet smoke temperature monitoring device, a 5-smoke pressure monitoring device, a 6-control terminal, a 7-boiler flue, an 8-medium inlet pipe, a 9-medium outlet pipe, a 10-flow control device, an 11-inlet medium temperature monitoring device, a 12-outlet medium temperature monitoring device, a 13-phase change heat exchanger, a 14-phase change heat exchange steam drum, a 15-heat exchange coil, a 16-downcomer and a 17-riser.
Detailed Description
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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.
The invention aims to provide a sulfur-containing flue gas waste heat recovery device and a control method, which are used for solving the problems in the prior art, can recycle waste heat in sulfur-containing flue gas and simultaneously avoid equipment corrosion.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
As shown in fig. 1-3, the embodiment provides a sulfur-containing flue gas waste heat recovery device 100, which includes a flue gas heat exchange device 1 and an SO2A concentration monitoring device 2 and a control terminal 6;
the flue gas heat exchange device 1 is used for being connected with a boiler flue 7 and can exchange heat with flue gas in the boiler flue 7, and a medium inlet pipe 8 and a medium outlet pipe 9 which are respectively used for the inflow and outflow of heat exchange media and a flow control device 10 which is used for controlling the flow of the heat exchange media in the flue gas heat exchange device 1 are arranged on the flue gas heat exchange device 1;
SO2the concentration monitoring device 2 is arranged in a flue between an inlet of a boiler flue 7 and the flue gas heat exchange device 1 and is electrically connected with the control terminal 6;
the control terminal 6 can be based on SO2SO measured by the concentration monitoring device 22The concentration is calculated to obtain the acid dew point temperature, and the flow control device 10 is controlled to ensure that the temperature of the flue gas after heat exchange is higher than the acid dew point temperature.
Determining SO according to type of boiler2With SO3In flue gas, SO, wherein in flue gas2And SO3An equilibrium state is maintained between the SO and the SO when the boiler is a pulverized coal boiler2With SO3The conversion rate is about 3% -5%, when the boiler is oil-fired boiler, it is 5% -10%, and when the boiler is chemical plant incinerator, it is 3.2% -8.7%, and the SO is used2Concentration monitoring device 2 monitors SO at inlet of boiler flue 7 in real time2Volume fraction and transmitted to the control terminal 6 according to SO2Volume fraction and SO2With SO3Control terminal 6 through SO2SO is calculated by multiplying the volume fraction by the conversion3Is calculated by volume fraction ofAccording to SO3The volume fraction is calculated to obtain the acid dew point temperature, then, according to the low-temperature corrosion principle, the temperature of the low-temperature heating surface of the boiler is ensured to be higher than the acid dew point temperature of the flue gas and higher than the acid dew point t ℃ of the flue gas, namely, the temperature of the flue gas outlet is higher than the acid dew point t ℃, the control terminal 6 controls the flow control device 10, heat exchange is carried out between the heat exchange medium and the flue gas, partial heat in the flue gas is transferred to the heat exchange medium, the waste heat of the flue gas is recycled, the temperature of the flue gas after heat exchange, namely the temperature of the flue gas outlet, is always higher than the acid dew point temperature, therefore, the sulfuric acid vapor is prevented from being condensed into sulfuric acid solution, the corrosion of boiler equipment is avoided, and the service life of the equipment is prolonged.
As shown in fig. 1, in this embodiment, the flue gas heat exchange device 1 includes a phase change heat exchanger 13, a phase change heat exchange steam drum 14 and a heat exchange coil 15, the phase change heat exchanger 13 is configured to be disposed in a flue between an inlet and an outlet of a flue of a boiler, the inlet and the outlet of the phase change heat exchanger 13 are respectively communicated with the inside of the phase change heat exchange steam drum 14 through a down pipe 16 and an up pipe 17, the heat exchange coil 15 is disposed in the phase change heat exchange steam drum 14, and two ends of the heat exchange coil 15 are respectively communicated with a medium inlet pipe 8 and a medium outlet pipe 9. Condensed water enters the phase-change heat exchanger 13 through the downcomer 16, the phase-change heat exchanger 13 absorbs smoke heat and turns into steam, the steam enters the phase-change heat exchange steam drum 14 through the riser 17, the phase-change heat exchange steam drum 14 is connected with a boiler main condensed water system in parallel, main condensed water enters the phase-change heat exchange steam drum 14 through the medium inlet pipe 8, the heat of the steam of the phase-change heat exchanger 13 is utilized to heat the main condensed water and then flows out along the medium outlet pipe 9, and therefore the purpose of recycling waste heat of the main condensed water required by the boiler heating system is achieved, meanwhile, the steam is condensed into water through cooling of the main condensed water, and then enters the phase-change heat exchanger 13 through the downcomer 16 to absorb waste heat of smoke.
As shown in fig. 2-3, in this embodiment, the phase change heat exchanger 13 is a spiral finned tube heat exchanger, and the heat exchange coil 15 is a serpentine heat exchange coil, so that the heat exchange effect is good.
As shown in fig. 1, in this embodiment, the system further includes a water vapor concentration monitoring device 3 and a flue gas pressure monitoring device 5, and the water vapor concentration monitoring device 3 and the flue gas pressure monitoring device 5 are used forIs arranged in the flue between the inlet of the boiler flue 7 and the flue gas heat exchange device 1 and is electrically connected with the control terminal 6. The volume fraction of the steam at the inlet of the boiler flue 7 and the pressure of the inlet flue gas are monitored in real time by the steam concentration monitoring device 3 and are transmitted to the control terminal 6. In the presence of SO2Volume fraction and SO2With SO3To obtain SO3After volume fraction of (A), if SO3Is higher than 35ppm, according to the formula h.a. bapahba:
if SO3In a volume fraction of not more than 35ppm, according to Haase&The Borgmann formula is:
wherein,
in the formula: t is tadp: acid dew point temperature;
the volume fraction of water vapor in the flue gas;
SO in flue gas3Volume fraction of (a);
SO in flue gas3Partial pressure of (a);
partial pressure of water vapor in the flue gas; p is a radical of0: inlet flue gas pressure; and the control terminal 6 calculates the acid dew point temperature according to the formula.
In this example, SO2The concentration monitoring device 2 comprises SO2The concentration sensor and the water vapor concentration monitoring device 3 comprise a flue gas moisture meter, the flue gas pressure monitoring device 5 comprises a flue gas pressure sensor and SO2The concentration sensor, the flue gas moisture meter and the flue gas pressure sensor are all electrically connected with the control terminal 6 and are connected with the control terminal through SO2Concentration sensor monitoring SO2The concentration is transmitted to the control terminal 6 to realize SO control2The real-time supervision of concentration, through flue gas moisture meter monitoring vapor concentration and transmit to control terminal 6, realize the real-time supervision to vapor concentration, through flue gas pressure sensor monitoring import flue gas pressure and transmit to control terminal 6, realize the real-time supervision to import flue gas pressure, simple structure is convenient for install.
In this embodiment, the flow control device 10 includes a flow control valve, and the flow control valve is disposed on the medium inlet pipe 8 and electrically connected to the control terminal 6, so that the structure is simple and the control is convenient.
As shown in fig. 1, in this embodiment, the system further includes an inlet flue gas temperature monitoring device 4, where the inlet flue gas temperature monitoring device 4 is arranged in a flue between an inlet of a boiler flue 7 and the flue gas heat exchange device 1; an inlet medium temperature monitoring device 11 is arranged on the medium inlet pipe 8, and an outlet medium temperature monitoring device 12 is arranged on the medium outlet pipe 9; the inlet smoke temperature monitoring device 4, the inlet medium temperature monitoring device 11 and the outlet medium temperature monitoring device 12 are all electrically connected with the control terminal 6. When the flue gas heat exchange device 1 exchanges heat with flue gas, the temperature of a flue gas outlet is ensured to be higher than the acid dew point t ℃ of the flue gas, and the method comprises the following steps according to the law of energy conservation:
in the formula: k0: the heat exchange efficiency of the flue gas heat exchange device is improved;
K1: heat exchange equipment protectorTemperature efficiency;
t1: inlet flue gas temperature;
Δ t: the temperature difference between the outlet medium temperature and the inlet medium temperature of the flue gas heat exchange device;
determining the smoke mass flow according to the type of the boiler
The control terminal 6 calculates the mass flow of the heat exchange medium according to the formula:
the control terminal 6 controls the flow control device 10 to ensure that the mass flow of the heat exchange medium of the flue gas heat exchange device 1 is controlled
Wherein, the heat exchange equipment heat preservation efficiency K1Refers to the product of the heat preservation efficiency of the flue gas heat exchange device 1 and the boiler flue 7, and the heat exchange efficiency K of the flue gas heat exchange device0The heat exchange medium is the main condensed water required by the boiler system, namely heat exchange medium heat, which is the product of the heat exchange efficiency of the phase change heat exchanger 13 and the heat exchange coil 15Container
The purpose of recycling the waste heat of the flue gas is achieved by heating main condensed water required by a boiler system for the heat capacity of water, and the SO is determined according to the type of the boiler2With SO3After the conversion rate and the mass flow of the flue gas are obtained, the control terminal 6 calculates the mass flow of the heat exchange medium, and controls the flow control valve according to the mass flow of the heat exchange medium, so that the actual mass flow of the heat exchange medium is equal to the mass flow of the heat exchange medium obtained by calculation, the temperature of the flue gas outlet is always higher than the acid dew point temperature, the sulfuric acid vapor is prevented from being condensed into a sulfuric acid solution, the corrosion of equipment is avoided, and the service life of the equipment is prolonged.
In this embodiment, inlet flue gas temperature monitoring devices 4 includes import flue gas temperature sensor, and import medium temperature monitoring devices 11 includes import medium temperature sensor, and export medium temperature monitoring devices 12 includes export medium temperature sensor, and import flue gas temperature sensor, import medium temperature sensor and export medium temperature sensor all are connected with control terminal 6 electricity, simple structure, simple to operate.
The waste heat recovery control method based on the sulfur-containing flue gas waste heat recovery device 100 comprises the following steps:
S1：SO2 concentration monitoring device 2 monitors SO at inlet of boiler flue 7 in real time2Volume fraction and transmitting to the control terminal 6;
s2: the control terminal 6 measures SO according to S12Calculating the volume fraction to obtain SO in the flue gas3Volume fraction of (a);
s3: control terminal 6 according to SO in S23Calculating the volume fraction of the flue gas to obtain the acid dew point temperature of the flue gas;
s4: the temperature of the low-temperature heating surface of the boiler is ensured to be higher than the acid dew point t ℃ of the flue gas, namely the temperature of the flue gas outlet is higher than the acid dew point t ℃ of the flue gas, wherein t is more than 0, and the control terminal 6 controls the flow control device 10 to ensure that the temperature of the flue gas after heat exchange is higher than the acid dew point temperature.
In the control method, a water vapor concentration monitoring device 3, an inlet smoke temperature monitoring device 4 and a smoke pressure monitoring device 5 monitor the volume fraction of water vapor at the inlet of a boiler flue 7, the inlet smoke temperature and the inlet smoke pressure in real time and transmit the volume fraction, the inlet smoke temperature and the inlet smoke pressure to a control terminal 6, and an inlet medium temperature monitoring device 11 and an outlet medium temperature monitoring device 12 monitor the inlet medium temperature and the outlet medium temperature of a smoke heat exchange device 1 in real time and transmit the inlet medium temperature and the outlet medium temperature to the control terminal 6;
selecting SO according to type of boiler2With SO3The conversion of (b) is then:
in formula (1):
η：SO2with SO3The conversion of (a);
the control terminal 6 calculates and obtains SO in the flue gas according to the formula (1)3Volume fraction of (a);
if SO3Is higher than 35ppm, according to the formula h.a. bapahba:
if SO3In a volume fraction of not more than 35ppm, according to Haase&The Borgmann formula is:
wherein,
formula (2) to formula (5):
tadp: acid dew point temperature;
p0: inlet flue gas pressure;
the control terminal 6 calculates according to the formula (2) -formula (5) to obtain the acid dew point temperature;
according to the low-temperature corrosion principle, the temperature of the low-temperature heating surface is ensured to be higher than the acid dew point t ℃ of the flue gas, namely the temperature of the flue gas outlet is higher than the acid dew point t ℃ of the flue gas, wherein t is more than 0, preferably 6-10, more preferably 8, and the energy conservation law is as follows:
in formula (6):
K0: the heat exchange efficiency of the flue gas heat exchange device is improved;
K1: the heat preservation efficiency of the heat exchange equipment is improved;
t1: inlet flue gas temperature;
Δ t: the temperature difference between the outlet medium temperature and the inlet medium temperature of the flue gas heat exchange device;
the control terminal 6 calculates the mass flow of the heat exchange medium according to the formula (6):
the control terminal 6 controls the flow control device 10 to ensure that the mass flow of the heat exchange medium of the flue gas heat exchange device 1 is controlled
Wherein, the heat exchange equipment heat preservation efficiency K1Refers to the product of the heat preservation efficiency of the flue gas heat exchange device 1 and the boiler flue 7, and the heat exchange efficiency K of the flue gas heat exchange device0The heat exchange medium is the main condensed water required by the boiler system, namely the heat capacity of the heat exchange medium, which is the product of the heat exchange efficiency of the phase change heat exchanger 13 and the heat exchange coil 15
The purpose of recycling the waste heat of the flue gas is achieved by heating main condensed water required by a boiler system for the heat capacity of water, and the SO is determined according to the type of the boiler2With SO3After conversion and flue gas mass flow rate, controllingThe terminal 6 calculates the mass flow of the heat exchange medium, and controls the flow control valve according to the mass flow of the heat exchange medium, so that the actual mass flow of the heat exchange medium is equal to the mass flow of the heat exchange medium obtained by calculation, the temperature of the flue gas outlet is always higher than the acid dew point temperature, the sulfuric acid vapor is prevented from being condensed into sulfuric acid solution, the corrosion of equipment is avoided, and the service life of the equipment is prolonged.
The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (10)
1. The utility model provides a contain sulphur flue gas waste heat recovery device which characterized in that: comprises a flue gas heat exchange device and SO2A concentration monitoring device and a control terminal;
the flue gas heat exchange device is used for being connected with a boiler flue and can exchange heat with flue gas in the boiler flue, and a medium inlet pipe and a medium outlet pipe which are respectively used for the inflow and outflow of heat exchange media and a flow control device which is used for controlling the flow of the heat exchange media in the flue gas heat exchange device are arranged on the flue gas heat exchange device;
the SO2The concentration monitoring device is arranged in a flue between a boiler flue inlet and the flue gas heat exchange device and is electrically connected with the control terminal;
the control terminal can be according to the SO2SO measured by concentration monitoring device2And calculating the concentration to obtain the acid dew point temperature, and controlling the flow control device to enable the temperature of the flue gas after heat exchange to be higher than the acid dew point temperature.
2. The sulfur-containing flue gas waste heat recovery device of claim 1, wherein: the flue gas heat exchange device comprises a phase change heat exchanger, a phase change heat exchange steam drum and a heat exchange coil, wherein the phase change heat exchanger is arranged in a flue between an inlet and an outlet of a boiler flue, the inlet and the outlet of the phase change heat exchanger are communicated with the inside of the phase change heat exchange steam drum through a descending pipe and an ascending pipe respectively, the heat exchange coil is arranged in the phase change heat exchange steam drum, and two ends of the heat exchange coil are communicated with a medium inlet pipe and a medium outlet pipe respectively.
3. The sulfur-containing flue gas waste heat recovery device of claim 2, wherein: the phase change heat exchanger is a spiral finned tube heat exchanger, and the heat exchange coil is a snakelike heat exchange coil.
4. The sulfur-containing flue gas waste heat recovery device of claim 1, wherein: the boiler flue gas heat exchange device is characterized by further comprising a water vapor concentration monitoring device and a flue gas pressure monitoring device, wherein the water vapor concentration monitoring device and the flue gas pressure monitoring device are used for being arranged at an inlet of a boiler flue and in a flue between the flue gas heat exchange devices and are electrically connected with the control terminal.
5. The device for recovering waste heat of sulfur-containing flue gas as claimed in claim 4, wherein: the SO2The concentration monitoring device comprises SO2The concentration sensor, the vapor concentration monitoring device comprises a flue gas moisture meter, the flue gas pressure monitoring device comprises a flue gas pressure sensor, and the SO2The concentration sensor, the smoke moisture meter and the smoke pressure sensor are all electrically connected with the control terminal.
6. The sulfur-containing flue gas waste heat recovery device of claim 1, wherein: the flow control device comprises a flow control valve which is arranged on the medium inlet pipe and is electrically connected with the control terminal.
7. The sulfur-containing flue gas waste heat recovery device of claim 1, wherein: the boiler flue gas heat exchange device is characterized by also comprising an inlet flue gas temperature monitoring device, wherein the inlet flue gas temperature monitoring device is arranged in a flue between a boiler flue inlet and the flue gas heat exchange device; an inlet medium temperature monitoring device is arranged on the medium inlet pipe, and an outlet medium temperature monitoring device is arranged on the medium outlet pipe; the inlet smoke temperature monitoring device, the inlet medium temperature monitoring device and the outlet medium temperature monitoring device are all electrically connected with the control terminal.
8. The device for recovering waste heat of sulfur-containing flue gas as claimed in claim 7, wherein: the inlet smoke temperature monitoring device comprises an inlet smoke temperature sensor, the inlet medium temperature monitoring device comprises an inlet medium temperature sensor, the outlet medium temperature monitoring device comprises an outlet medium temperature sensor, and the inlet smoke temperature sensor, the inlet medium temperature sensor and the outlet medium temperature sensor are electrically connected with the control terminal.
9. A waste heat recovery control method based on the sulfur-containing flue gas waste heat recovery device of any one of claims 1 to 8 is characterized by comprising the following steps:
s1: the SO2SO of boiler flue inlet is monitored in real time to concentration monitoring device2Volume fraction and transmitting to the control terminal;
s2: the control terminal measures SO according to S12Calculating the volume fraction to obtain SO in the flue gas3Volume fraction of (a);
s3: the control terminal controls the control terminal according to SO in S23Calculating the volume fraction of the flue gas to obtain the acid dew point temperature of the flue gas;
s4: and ensuring that the temperature of the low-temperature heating surface of the boiler is higher than the acid dew point t ℃ of the flue gas, namely the temperature of the flue gas outlet is higher than the acid dew point t ℃ of the flue gas, wherein t is more than 0, and the control terminal controls the flow control device to ensure that the temperature of the flue gas after heat exchange is higher than the acid dew point temperature.
10. The control method according to claim 9, characterized in that:
the steam concentration monitoring device, the inlet smoke temperature monitoring device and the smoke pressure monitoring device monitor the steam volume fraction, the inlet smoke temperature and the inlet smoke pressure of the boiler flue inlet in real time and transmit the steam volume fraction, the inlet smoke temperature and the inlet smoke pressure to the control terminal, and the inlet medium temperature monitoring device and the outlet medium temperature monitoring device monitor the inlet medium temperature and the outlet medium temperature of the smoke heat exchange device in real time and transmit the inlet medium temperature and the outlet medium temperature to the control terminal;
selecting SO according to type of boiler2With SO3The conversion of (b) is then:
in formula (1):
η：SO2with SO3The conversion of (a);
the control terminal calculates according to the formula (1) to obtain SO in the flue gas3Volume fraction of (a);
if SO3Volume fraction of above 35ppm, according to the formula of a. bapahoa:
if SO3In a volume fraction of not more than 35ppm, according to Haase&The Borgmann formula is:
wherein,
formula (2) to formula (5):
tadp: acid dew point temperature;
p0: inlet flue gas pressure;
the control terminal calculates according to the formula (2) to the formula (5) to obtain the acid dew point temperature;
ensuring that the temperature of the flue gas outlet is higher than the acid dew point t ℃ of the flue gas, and according to the law of energy conservation, the method comprises the following steps:
in formula (6):
K0: the heat exchange efficiency of the flue gas heat exchange device is improved;
K1: the heat preservation efficiency of the heat exchange equipment is improved;
t1: inlet flue gas temperature;
Δ t: the temperature difference between the outlet medium temperature and the inlet medium temperature of the flue gas heat exchange device;
the control terminal calculates the mass flow of the heat exchange medium according to the formula (6):
the control terminal controls the flow control device to ensure that the mass flow of the heat exchange medium of the flue gas heat exchange device is controlled
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| CN117643784A (en) * | 2023-12-20 | 2024-03-05 | 中科新天地（合肥）环保科技有限公司 | Multi-pollutant cooperative treatment control method and system |
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Application publication date: 20220104 |