CN111521226A - Draught fan inlet flue gas flow measuring device and method - Google Patents

Draught fan inlet flue gas flow measuring device and method Download PDF

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Publication number
CN111521226A
CN111521226A CN202010500474.8A CN202010500474A CN111521226A CN 111521226 A CN111521226 A CN 111521226A CN 202010500474 A CN202010500474 A CN 202010500474A CN 111521226 A CN111521226 A CN 111521226A
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flue gas
low
inlet
temperature economizer
specific heat
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吴万范
许文良
邓中乙
潘存华
马启磊
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Datang Boiler Pressure Vessel Examination Center Co Ltd
East China Electric Power Test Institute of China Datang Corp Science and Technology Research Institute Co Ltd
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Datang Boiler Pressure Vessel Examination Center Co Ltd
East China Electric Power Test Institute of China Datang Corp Science and Technology Research Institute Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
    • G01F1/34—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis

Abstract

The invention discloses a device and a method for measuring the flow of flue gas at the inlet of an induced draft fan, wherein the device comprises a boiler, a first SCR (selective catalytic reduction) denitration device, a first air preheater, a first dust remover, a first low-temperature economizer, a first induced draft fan, a desulfurizing tower and a chimney which are sequentially connected through a pipeline, and an electrochemical flue gas analyzer, a resistance-capacitance type flue gas hygrometer, a first thermocouple and a second thermocouple which are electrically connected with a controller are arranged in the pipeline in front of the first low-temperature economizer; a pipeline behind the first low-temperature economizer is provided with a third thermocouple, a fourth thermocouple, a flow meter and a pressure gauge which are electrically connected with the controller; the invention has the advantages that: the method has the advantages that the flue gas flow at the inlet of the induced draft fan is measured, the furnace slag is not required to indirectly obtain the flue gas flow, the quantitative analysis of the extraction of the components of the furnace slag is not required, the measuring method is simple, and the consumed time is short.

Description

Draught fan inlet flue gas flow measuring device and method
Technical Field
The invention relates to the technical field of draught fan inlet flow measurement of coal-fired units provided with low-temperature economizers, in particular to a draught fan inlet flue gas flow measurement device and method.
Background
At present, large coal-fired power generating units are compact in equipment layout, pipelines at the tail of a boiler are short in length and have more elbows, straight-section pipelines suitable for measuring the flow velocity of smoke are almost not arranged at the front and the back of an induced draft fan, and the measured smoke flow error at the inlet of the induced draft fan is large due to the fact that a speed field at a measuring position is uneven and a flow field is disturbed greatly in a traditional pneumatic speed measuring method used by a power plant. However, the index of the smoke amount at the inlet of the induced draft fan is very important in measuring the performance of the induced draft fan, calculating the environmental protection index and controlling the operation of the boiler. Therefore, the method for more accurately measuring the inlet flue gas flow of the induced draft fan has important significance in research and development.
Chinese patent application number CN201811074014.2 provides a measure testing platform of power boiler draught fan efficiency, belongs to coal fired boiler energy saving technology field, including sampling device to and controlling means, through the data acquisition unit with each sensor electricity respectively connects among the sampling device for gather the data that each sensor gathered, combine to type into controlling means's power boiler raw data calculates out power boiler draught fan efficiency. The method for measuring the efficiency of the induced draft fan of the utility boiler is further provided. The method aims to solve the technical problems of low test precision, more high-altitude operation, high labor intensity and long test time consumption of the conventional method for detecting the efficiency of the induced draft fan. The method is characterized in that the smoke volume of the draught fan is not measured any more during measurement, but the raw coal and the large slag entering the furnace are sampled and analyzed, the fly ash and the large slag on the side of the draught fan are sampled and analyzed, the smoke volume calculation model is established from the fuel balance angle through the smoke analysis at the inlet of the draught fan, and therefore the air power and the efficiency of the draught fan are calculated. The flue gas flow is indirectly obtained through the slag, the quantitative analysis needs to be carried out after the slag components are extracted, the measuring method is complex, and the time consumption is long.
Disclosure of Invention
The invention aims to solve the technical problems that the measuring method of the draught fan inlet flue gas flow measuring device and the method in the prior art is complex and consumes long time.
The invention solves the technical problems through the following technical means: a draught fan inlet flue gas flow measuring device comprises a boiler, a first SCR pin removal device, a first air preheater, a first dust remover, a first low-temperature economizer, a first draught fan, a desulfurizing tower and a chimney which are sequentially connected through a pipeline, wherein an electrochemical flue gas analyzer, a resistance-capacitance type flue gas hygrometer, a first thermocouple and a second thermocouple which are electrically connected with a controller are arranged in the pipeline in front of the first low-temperature economizer; a pipeline behind the first low-temperature economizer is provided with a third thermocouple, a fourth thermocouple, a flow meter and a pressure gauge which are electrically connected with the controller;
the electrochemical flue gas analyzer is used for acquiring the volume fraction of oxygen in dry flue gas and the volume fraction of carbon dioxide in the dry flue gas, the resistance-capacitance flue gas hygrometer is used for acquiring the volume fraction of water vapor in wet flue gas, the first thermocouple is used for acquiring the temperature of flue gas at the inlet of the first low-temperature economizer, and the second thermocouple is used for acquiring the temperature of water in a water inlet pipeline of the low-temperature economizer; the third thermocouple is used for collecting the temperature of flue gas at the outlet of the low-temperature economizer, the fourth thermocouple is used for collecting the water temperature of a water outlet pipeline of the low-temperature economizer, the flowmeter is used for collecting the water flow of a water inlet pipeline of the low-temperature economizer, and the pressure gauge is used for collecting the static pressure of the flue gas at the inlet of the induced draft fan; and the controller calculates the flue gas flow at the inlet of the induced draft fan according to the acquired data.
According to the invention, the volume fraction of oxygen in dry flue gas, the volume fraction of carbon dioxide in dry flue gas, the volume fraction of water vapor in wet flue gas, the inlet flue gas temperature of the first low-temperature economizer, the water temperature of a water inlet pipeline of the low-temperature economizer and the like are collected by detection equipment, the controller calculates the inlet flue gas flow of the induced draft fan according to the collected data, the slag is not required to indirectly obtain the flue gas flow, the extraction of slag components is not required to be quantitatively analyzed, the measurement method is simple, and the time consumption is short.
Further, draught fan import flue gas flow measuring device still includes second SCR and takes off round pin device, second air preheater, second dust remover, second low temperature economizer and second draught fan, boiler, second SCR take off round pin device, second air preheater, second dust remover, second low temperature economizer, second draught fan and desulfurizing tower pass through the pipeline and connect in order.
Further, draught fan import flue gas flow measuring device still includes the host computer, the host computer with the controller is connected, and the host computer shows draught fan import flue gas flow in real time.
Further, the model of the controller is STC12C 5410.
Further, the controller calculates the draught fan inlet flue gas flow according to the collected data and comprises: the method comprises the steps of obtaining the constant-pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer, the constant-pressure specific heat capacity of wet flue gas at the outlet of the low-temperature economizer, the specific heat capacities of water at two temperatures and the water flow of a water inlet pipeline of the low-temperature economizer according to collected data, and obtaining the flue gas flow at the inlet of the induced draft fan in a standard state according to the constant-pressure specific heat capacity of the wet flue gas at the inlet of the low-temperature economizer, the constant-pressure specific heat capacity of the wet flue gas at the outlet of the low-temperature economizer, the specific heat capacities of.
The invention also provides a measuring method of the draught fan inlet flue gas flow measuring device, which comprises the following steps:
the method comprises the following steps: acquiring the constant-pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer;
step two: acquiring the constant-pressure specific heat capacity of wet flue gas at the outlet of the low-temperature economizer;
step three: acquiring the water temperature of a water inlet pipeline of the low-temperature economizer and the water temperature of a water outlet pipeline of the low-temperature economizer, and acquiring the specific heat capacity of water at the two water temperatures according to a specific heat capacity table of the water;
step four: acquiring the flue gas flow at the inlet of the induced draft fan in a standard state according to the constant-pressure specific heat capacity of the wet flue gas at the inlet of the low-temperature economizer, the constant-pressure specific heat capacity of the wet flue gas at the outlet of the low-temperature economizer, the specific heat capacities of the water at two water temperatures and the water flow of a water inlet pipeline of the low-temperature economizer;
step five: and acquiring the real-time flue gas flow of the inlet of the induced draft fan according to the static pressure of the flue gas at the inlet of the induced draft fan and the flue gas flow at the inlet of the induced draft fan in a standard state.
Further, the first step comprises:
collecting the volume fraction phi of oxygen in dry flue gas at the inlet of a low-temperature economizerO2Volume fraction of carbon dioxide in dry flue gasCO2Volume fraction of water vapour in wet flue gasH2OAnd inlet flue gas temperature Tfg.en；
Neglecting the influence of trace carbon monoxide, nitrogen oxide and sulfur dioxide in the flue gas, and passing through a formula phiN2＝100-φO2-φCO2Obtaining the volume fraction of nitrogen in the dry flue gas, wherein phiN2Is the volume fraction of nitrogen in the dry flue gas;
using formulas
Figure BDA0002524614100000041
Obtaining the constant pressure specific heat capacity of dry flue gas at the inlet of the low-temperature economizer, wherein Cp.gy.enThe constant pressure specific heat capacity of dry flue gas at the inlet of a low-temperature economizer, Cp.CO2Is the constant pressure specific heat capacity of carbon dioxide at the inlet of a low-temperature economizer, Cp.O2Constant pressure specific heat capacity for oxygen at inlet of low-temperature economizer, Cp.N2The nitrogen gas inlet of the low-temperature economizer has a constant pressure and specific heat capacity, wherein,
Figure BDA0002524614100000042
Figure BDA0002524614100000043
Figure BDA0002524614100000044
using formulas
Figure BDA0002524614100000045
Obtaining the constant pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer, wherein Cp.sy.enThe constant pressure specific heat capacity of the wet flue gas at the inlet of the low-temperature economizer, Cp.H2OThe specific heat capacity of the inlet steam of the low-temperature economizer is constant pressure
Figure BDA0002524614100000046
Further, the second step comprises:
according to the mass conservation principle, the volume fraction of each gas component at the outlet of the low-temperature economizer is completely equal to the volume fraction of each gas component at the inlet of the low-temperature economizer, and the temperature T of the flue gas at the outlet of the low-temperature economizer is collectedfg.1v；
Neglecting the influence of trace carbon monoxide, nitrogen oxide and sulfur dioxide in the flue gas, and passing through a formula phiN2＝100-φO2-φCO2Obtaining the volume fraction of nitrogen in the dry flue gas, wherein phiN2Is the volume fraction of nitrogen in the dry flue gas;
using formulas
Figure BDA0002524614100000051
Obtaining the constant pressure specific heat capacity of dry flue gas at the outlet of the low-temperature economizer, wherein Cp.gy.1vThe constant pressure specific heat capacity of dry flue gas at the outlet of the low-temperature economizer is Cp.CO2' is the specific heat capacity at constant pressure of carbon dioxide at the outlet of the low-temperature economizer, Cp.O2' is the constant pressure specific heat capacity of oxygen at the outlet of the low-temperature economizer, Cp.N2' is the constant pressure specific heat capacity of nitrogen at the outlet of the low-temperature economizer, wherein,
Figure BDA0002524614100000052
Figure BDA0002524614100000053
Figure BDA0002524614100000054
using formulas
Figure BDA0002524614100000055
Obtaining the constant pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer, wherein Cp.sy.1vThe constant pressure specific heat capacity of the wet flue gas at the outlet of the low-temperature economizer, Cp.H2OIs the specific heat capacity of the water vapor at the outlet of the low-temperature economizer at constant pressure
Figure BDA0002524614100000056
Further, the fourth step includes:
using formulas
Figure BDA0002524614100000057
Obtaining the enthalpy of the smoke reduced by the low-temperature economizer, wherein, Delta HsyEnthalpy of flue gas reduced by low-temperature economizer, Bfg.NThe flow rate of the smoke at the inlet of the induced draft fan is in a standard state;
using formulas
Figure BDA0002524614100000058
Obtaining the enthalpy of the heating medium water increased by the low-temperature economizer, wherein, Delta HwEnthalpy added for hot media water passing through low-temperature economizer, BwIs the water flow of the water inlet pipeline of the low-temperature economizer, Cw.enIs the specific heat capacity at the water temperature of the water inlet pipeline of the low-temperature economizer, Cw.lvThe specific heat capacity of the water temperature of the water outlet pipeline of the low-temperature economizer is obtained;
from heat balance Δ Hsy＝ΔHwCan obtain the smoke flow at the inlet of the induced draft fan under the standard state
Figure BDA0002524614100000061
Further, the fifth step includes:
collecting static pressure of inlet flue gas of the induced draft fan, and acquiring real-time inlet flue gas flow of the induced draft fan according to the static pressure of the inlet flue gas of the induced draft fan and the inlet flue gas flow of the induced draft fan in a standard state
Figure BDA0002524614100000062
Wherein, BfgFor real-time draught fan inlet flue gas flow, PfgIs the static pressure of the smoke at the inlet of the draught fan.
The invention has the advantages that:
(1) according to the invention, the volume fraction of oxygen in dry flue gas, the volume fraction of carbon dioxide in dry flue gas, the volume fraction of water vapor in wet flue gas, the inlet flue gas temperature of the first low-temperature economizer, the water temperature of a water inlet pipeline of the low-temperature economizer and the like are collected by detection equipment, the controller calculates the inlet flue gas flow of the induced draft fan according to the collected data, the slag is not required to indirectly obtain the flue gas flow, the extraction of slag components is not required to be quantitatively analyzed, the measurement method is simple, and the time consumption is short.
(2) According to the invention, two gas treatment systems come out from the boiler, one is a first SCR pin removal device, a first air preheater, a first dust remover, a first low-temperature economizer and a first induced draft fan, and the other is a second SCR pin removal device, a second air preheater, a second dust remover, a second low-temperature economizer and a second induced draft fan.
Drawings
Fig. 1 is a structural diagram of a flow measuring device for flue gas at an inlet of an induced draft fan according to an embodiment of the present invention;
FIG. 2 is an electrical block diagram of a flue gas flow measuring device at an inlet of an induced draft fan according to an embodiment of the present invention;
fig. 3 is a flowchart of a method for measuring a flow rate of flue gas at an inlet of an induced draft fan according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all 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.
Example 1
As shown in fig. 1, a draught fan inlet flue gas flow measuring device, include through the boiler 1 that the pipeline links to each other in order, first SCR denitration device 2, first air preheater 3, first dust remover 4, first low temperature economizer 5, first draught fan 6, desulfurizing tower 7 and chimney 8, still include second SCR denitration device 9, second air preheater 10, second dust remover 11, second low temperature economizer 12 and second draught fan 13, boiler 1, second SCR denitration device 9, second air preheater 10, second dust remover 11, second low temperature economizer 12, second draught fan 13 and desulfurizing tower 7 pass through the pipeline and connect in order.
As shown in fig. 2, the pipeline in front of the first low-temperature economizer 5 is provided with an electrochemical flue gas analyzer 15, a resistance-capacitance flue gas humidity meter 16, a first thermocouple 17 and a second thermocouple 18 which are electrically connected with a controller 14; a pipeline behind the first low-temperature economizer 5 is provided with a third thermocouple 19, a fourth thermocouple 20, a flow meter 21 and a pressure gauge 22 which are electrically connected with the controller 14; the model of the controller 14 is STC12C5410, the STC12C5410 is provided with an ADC unit, an electrochemical flue gas analyzer 15, a resistance-capacitance type flue gas hygrometer 16, a first thermocouple 17, a second thermocouple 18, a third thermocouple 19, a fourth thermocouple 20, a flow meter 21 and a pressure gauge 22 are respectively connected with an AD interface of the STC12C5410, analog quantity signals are converted into digital quantity signals, an algorithm built in the STC12C5410 is used for calculating the flow of flue gas at the inlet of the induced draft fan, the constant pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer, the constant pressure specific heat capacity of wet flue gas at the outlet of the low-temperature economizer, the specific heat capacities of water at two water temperatures and the water flow of a water inlet pipeline of the low-temperature economizer are obtained according to the collected data, and the flow of flue gas at the inlet of the induced draft fan under a standard state is obtained according to the constant pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer, the, the calculation method and process are specifically the method disclosed in embodiment 2, and are not described herein again.
The electrochemical flue gas analyzer 15 is used for acquiring the volume fraction of oxygen in dry flue gas and the volume fraction of carbon dioxide in the dry flue gas, the resistance-capacitance flue gas humidity instrument 16 is used for acquiring the volume fraction of water vapor in wet flue gas, the first thermocouple 17 is used for acquiring the temperature of flue gas at the inlet of the first low-temperature economizer 5, and the second thermocouple 18 is used for acquiring the water temperature of a water inlet pipeline of the low-temperature economizer; the third thermocouple 19 is used for collecting the temperature of the flue gas at the outlet of the low-temperature economizer, the fourth thermocouple 20 is used for collecting the water temperature of the water outlet pipeline of the low-temperature economizer, the flowmeter 21 is used for collecting the water flow of the water inlet pipeline of the low-temperature economizer, and the pressure gauge 22 is used for collecting the static pressure of the flue gas at the inlet of the induced draft fan; and the controller 14 calculates the smoke flow at the inlet of the induced draft fan according to the acquired data.
Continuing to refer to fig. 2, the draught fan inlet flue gas flow measuring device further comprises an upper computer 23, the upper computer 23 is connected with the controller 14, and the upper computer 23 displays the draught fan inlet flue gas flow in real time.
Through the technical scheme, the invention provides a draught fan inlet flue gas flow measuring device, the volume fraction of oxygen in dry flue gas, the volume fraction of carbon dioxide in the dry flue gas, the volume fraction of water vapor in wet flue gas, the temperature of the flue gas at the inlet of a first low-temperature economizer 5, the water temperature of a water inlet pipeline of the low-temperature economizer and the like are collected through detection equipment, the controller 14 calculates the draught fan inlet flue gas flow according to the collected data, slag is not needed to indirectly obtain the flue gas flow, the extraction of slag components is not needed to be quantitatively analyzed, the measuring method is simple, and the time consumption is short.
Example 2
As shown in fig. 3, corresponding to embodiment 1 of the present invention, embodiment 2 of the present invention further provides a method for measuring a flue gas flow at an inlet of an induced draft fan, which is applied to a coal-fired power generating unit provided with a low-temperature economizer, and the method includes:
step S1: acquiring the constant-pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer; the specific process is as follows:
collecting the volume fraction phi of oxygen in dry flue gas at the inlet of a low-temperature economizerO2Volume fraction of carbon dioxide in dry flue gasCO2Volume fraction of water vapour in wet flue gasH2OAnd inlet flue gas temperature Tfg.en；
Neglecting the influence of trace carbon monoxide, nitrogen oxide and sulfur dioxide in the flue gas, and passing through a formula phiN2＝100-φO2-φCO2Obtaining the volume fraction of nitrogen in the dry flue gas, wherein phiN2Is the volume fraction of nitrogen in the dry flue gas;
using formulas
Figure BDA0002524614100000091
Obtaining the constant pressure specific heat capacity of dry flue gas at the inlet of the low-temperature economizer, wherein Cp.gy.enThe constant pressure specific heat capacity of dry flue gas at the inlet of a low-temperature economizer, Cp.CO2Is the constant pressure specific heat capacity of carbon dioxide at the inlet of a low-temperature economizer, Cp.O2Constant pressure specific heat capacity for oxygen at inlet of low-temperature economizer, Cp.N2The nitrogen gas inlet of the low-temperature economizer has a constant pressure and specific heat capacity, wherein,
Figure BDA0002524614100000092
Figure BDA0002524614100000093
Figure BDA0002524614100000101
using formulas
Figure BDA0002524614100000102
Obtaining the constant pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer, wherein Cp.sy.enFor the inlet wet flue gas of the low-temperature economizerSpecific heat capacity under pressure, Cp.H2OThe specific heat capacity of the inlet steam of the low-temperature economizer is constant pressure
Figure BDA0002524614100000103
Step S2: acquiring the constant-pressure specific heat capacity of wet flue gas at the outlet of the low-temperature economizer; the specific process is as follows:
according to the mass conservation principle, the volume fraction of each gas component at the outlet of the low-temperature economizer is completely equal to the volume fraction of each gas component at the inlet of the low-temperature economizer, and the temperature T of the flue gas at the outlet of the low-temperature economizer is collectedfg.1v；
Neglecting the influence of trace carbon monoxide, nitrogen oxide and sulfur dioxide in the flue gas, and passing through a formula phiN2＝100-φO2-φCO2Obtaining the volume fraction of nitrogen in the dry flue gas, wherein phiN2Is the volume fraction of nitrogen in the dry flue gas;
using formulas
Figure BDA0002524614100000104
Obtaining the constant pressure specific heat capacity of dry flue gas at the outlet of the low-temperature economizer, wherein Cp.gy.1vThe constant pressure specific heat capacity of dry flue gas at the outlet of the low-temperature economizer is Cp.CO2' is the specific heat capacity at constant pressure of carbon dioxide at the outlet of the low-temperature economizer, Cp.O2' is the constant pressure specific heat capacity of oxygen at the outlet of the low-temperature economizer, Cp.N2' is the constant pressure specific heat capacity of nitrogen at the outlet of the low-temperature economizer, wherein,
Figure BDA0002524614100000105
Figure BDA0002524614100000106
Figure BDA0002524614100000107
using formulas
Figure BDA0002524614100000108
Obtaining the constant pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer, wherein Cp.sy.1vThe constant pressure specific heat capacity of the wet flue gas at the outlet of the low-temperature economizer, Cp.H2OIs the specific heat capacity of the water vapor at the outlet of the low-temperature economizer at constant pressure
Figure BDA0002524614100000111
Step S3: acquiring the water temperature of a water inlet pipeline of the low-temperature economizer and the water temperature of a water outlet pipeline of the low-temperature economizer, and acquiring the specific heat capacity of water at the two water temperatures according to a specific heat capacity table of the water; the specific heat capacity of water is shown in Table 1.
TABLE 1 specific Heat of Water Table kJ/(kg. ℃ C.)
Figure BDA0002524614100000112
Step S4: acquiring the flue gas flow at the inlet of the induced draft fan in a standard state according to the constant-pressure specific heat capacity of the wet flue gas at the inlet of the low-temperature economizer, the constant-pressure specific heat capacity of the wet flue gas at the outlet of the low-temperature economizer, the specific heat capacities of the water at two water temperatures and the water flow of a water inlet pipeline of the low-temperature economizer; the specific process is as follows:
using formulas
Figure BDA0002524614100000113
Obtaining the enthalpy of the smoke reduced by the low-temperature economizer, wherein, Delta HsyEnthalpy of flue gas reduced by low-temperature economizer, Bfg.NThe flow rate of the smoke at the inlet of the induced draft fan is in a standard state;
using formulas
Figure BDA0002524614100000121
Obtaining the enthalpy of the heating medium water increased by the low-temperature economizer, wherein, Delta HwEnthalpy added for hot media water passing through low-temperature economizer, BwIs the water flow of the water inlet pipeline of the low-temperature economizer, Cw.enIs the specific heat capacity at the water temperature of the water inlet pipeline of the low-temperature economizer, Cw.lvThe specific heat capacity of the water temperature of the water outlet pipeline of the low-temperature economizer is obtained;
from heat balance Δ Hsy＝ΔHwCan obtain the smoke flow at the inlet of the induced draft fan under the standard state
Figure BDA0002524614100000122
Step S5: the method comprises the following steps of obtaining real-time draught fan inlet flue gas flow according to draught fan inlet flue gas static pressure and draught fan inlet flue gas flow under a standard state, wherein the specific process is as follows:
collecting static pressure of inlet flue gas of the induced draft fan, and acquiring real-time inlet flue gas flow of the induced draft fan according to the static pressure of the inlet flue gas of the induced draft fan and the inlet flue gas flow of the induced draft fan in a standard state
Figure BDA0002524614100000123
Wherein, BfgFor real-time draught fan inlet flue gas flow, PfgIs the static pressure of the smoke at the inlet of the draught fan.
It should be noted that, considering the accuracy of the measurement, the volume fraction φ of oxygen in the dry flue gas of the low-temperature economizerO2Volume fraction of carbon dioxide in dry flue gasCO2Volume fraction of water vapour in wet flue gasH2OInlet flue gas temperature Tfg.enAnd the temperature T of the flue gas at the outlet of the low-temperature economizerfg.1vAnd static pressure P of flue gas at inlet of draught fanfgThe number of the measuring points is at least 3 along the width direction of the pipeline at equal intervals, and the average value of the corresponding measuring data is taken as a calculating parameter to be substituted into a real-time draught fan inlet flue gas flow calculating formula to participate in calculation.
It should be noted that the method of embodiment 2 of the present invention can be applied to the first low-temperature economizer 5 and the second low-temperature economizer 12 of embodiment 1, so all parameters are not limited to the first low-temperature economizer 5 or the second low-temperature economizer 12, when applied to the first low-temperature economizer 5, all the parameters are the first low-temperature economizer 5 parameters, and when applied to the second low-temperature economizer 12, all the parameters are the second low-temperature economizer 12 parameters. Of course, the method of the invention can also be applied to other generator sets with low-temperature economizers.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. A draught fan inlet flue gas flow measuring device is characterized by comprising a boiler, a first SCR pin removal device, a first air preheater, a first dust remover, a first low-temperature economizer, a first draught fan, a desulfurizing tower and a chimney which are sequentially connected through a pipeline, wherein an electrochemical flue gas analyzer, a resistance-capacitance type flue gas humidity meter, a first thermocouple and a second thermocouple which are electrically connected with a controller are arranged in the pipeline in front of the first low-temperature economizer; a pipeline behind the first low-temperature economizer is provided with a third thermocouple, a fourth thermocouple, a flow meter and a pressure gauge which are electrically connected with the controller;
the electrochemical flue gas analyzer is used for acquiring the volume fraction of oxygen in dry flue gas and the volume fraction of carbon dioxide in the dry flue gas, the resistance-capacitance flue gas hygrometer is used for acquiring the volume fraction of water vapor in wet flue gas, the first thermocouple is used for acquiring the temperature of flue gas at the inlet of the first low-temperature economizer, and the second thermocouple is used for acquiring the temperature of water in a water inlet pipeline of the low-temperature economizer; the third thermocouple is used for collecting the temperature of flue gas at the outlet of the low-temperature economizer, the fourth thermocouple is used for collecting the water temperature of a water outlet pipeline of the low-temperature economizer, the flowmeter is used for collecting the water flow of a water inlet pipeline of the low-temperature economizer, and the pressure gauge is used for collecting the static pressure of the flue gas at the inlet of the induced draft fan; and the controller calculates the flue gas flow at the inlet of the induced draft fan according to the acquired data.
2. The induced draft fan inlet flue gas flow measuring device according to claim 1, further comprising a second SCR denitration device, a second air preheater, a second dust remover, a second low-temperature economizer and a second induced draft fan, wherein the boiler, the second SCR denitration device, the second air preheater, the second dust remover, the second low-temperature economizer, the second induced draft fan and the desulfurizing tower are connected in sequence through pipelines.
3. The draught fan inlet flue gas flow measuring device according to claim 1, further comprising an upper computer, wherein the upper computer is connected with the controller, and the upper computer displays the draught fan inlet flue gas flow in real time.
4. The draft fan inlet flue gas flow measurement device according to claim 1, wherein the controller is STC12C 5410.
5. The induced draft fan inlet flue gas flow measuring device according to claim 1, wherein the controller calculating the induced draft fan inlet flue gas flow according to the collected data comprises: the method comprises the steps of obtaining the constant-pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer, the constant-pressure specific heat capacity of wet flue gas at the outlet of the low-temperature economizer, the specific heat capacities of water at two temperatures and the water flow of a water inlet pipeline of the low-temperature economizer according to collected data, and obtaining the flue gas flow at the inlet of the induced draft fan in a standard state according to the constant-pressure specific heat capacity of the wet flue gas at the inlet of the low-temperature economizer, the constant-pressure specific heat capacity of the wet flue gas at the outlet of the low-temperature economizer, the specific heat capacities of.
6. The method for measuring the flow measurement device of the flue gas at the inlet of the induced draft fan according to any one of the claims 1 to 5, wherein the method comprises the following steps:
the method comprises the following steps: acquiring the constant-pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer;
step two: acquiring the constant-pressure specific heat capacity of wet flue gas at the outlet of the low-temperature economizer;
step three: acquiring the water temperature of a water inlet pipeline of the low-temperature economizer and the water temperature of a water outlet pipeline of the low-temperature economizer, and acquiring the specific heat capacity of water at the two water temperatures according to a specific heat capacity table of the water;
step four: acquiring the flue gas flow at the inlet of the induced draft fan in a standard state according to the constant-pressure specific heat capacity of the wet flue gas at the inlet of the low-temperature economizer, the constant-pressure specific heat capacity of the wet flue gas at the outlet of the low-temperature economizer, the specific heat capacities of the water at two water temperatures and the water flow of a water inlet pipeline of the low-temperature economizer;
step five: and acquiring the real-time flue gas flow of the inlet of the induced draft fan according to the static pressure of the flue gas at the inlet of the induced draft fan and the flue gas flow at the inlet of the induced draft fan in a standard state.
7. The method for measuring the draught fan inlet flue gas flow according to claim 6, wherein the first step comprises the following steps:
collecting the volume fraction phi of oxygen in dry flue gas at the inlet of a low-temperature economizerO2Volume fraction of carbon dioxide in dry flue gasCO2Volume fraction of water vapour in wet flue gasH2OAnd inlet flue gas temperature Tfg.en；
Neglecting the influence of trace carbon monoxide, nitrogen oxide and sulfur dioxide in the flue gas, and passing through a formula phiN2＝100-φO2-φCO2Obtaining the volume fraction of nitrogen in the dry flue gas, wherein phiN2Is the volume fraction of nitrogen in the dry flue gas;
using formulas
Figure FDA0002524614090000031
Obtaining the constant pressure specific heat capacity of dry flue gas at the inlet of the low-temperature economizer, wherein Cp.gy.enThe constant pressure specific heat capacity of dry flue gas at the inlet of a low-temperature economizer, Cp.CO2Is the constant pressure specific heat capacity of carbon dioxide at the inlet of a low-temperature economizer, Cp.O2Constant pressure specific heat capacity for oxygen at inlet of low-temperature economizer, Cp.N2The nitrogen gas inlet of the low-temperature economizer has a constant pressure and specific heat capacity, wherein,
Figure FDA0002524614090000032
Figure FDA0002524614090000033
Figure FDA0002524614090000034
using formulas
Figure FDA0002524614090000035
Obtaining the constant pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer, wherein Cp.sy.enThe constant pressure specific heat capacity of the wet flue gas at the inlet of the low-temperature economizer, Cp.H2OThe specific heat capacity of the inlet steam of the low-temperature economizer is constant pressure
Figure FDA0002524614090000036
8. The method for measuring the draught fan inlet flue gas flow according to claim 6, wherein the second step comprises the following steps:
according to the mass conservation principle, the volume fraction of each gas component at the outlet of the low-temperature economizer is completely equal to the volume fraction of each gas component at the inlet of the low-temperature economizer, and the temperature T of the flue gas at the outlet of the low-temperature economizer is collectedfg.1v；
Neglecting the influence of trace carbon monoxide, nitrogen oxide and sulfur dioxide in the flue gas, and passing through a formula phiN2＝100-φO2-φCO2Obtaining the volume fraction of nitrogen in the dry flue gas, wherein phiN2Is the volume fraction of nitrogen in the dry flue gas;
using formulas
Figure FDA0002524614090000041
Obtaining the constant pressure specific heat capacity of dry flue gas at the outlet of the low-temperature economizer, wherein Cp.gy.1vThe constant pressure specific heat capacity of dry flue gas at the outlet of the low-temperature economizer is Cp.CO2' is the specific heat capacity at constant pressure of carbon dioxide at the outlet of the low-temperature economizer, Cp.O2' is the constant pressure specific heat capacity of oxygen at the outlet of the low-temperature economizer, Cp.N2' is the constant pressure specific heat capacity of nitrogen at the outlet of the low-temperature economizer, wherein,
Figure FDA0002524614090000042
Figure FDA0002524614090000043
Figure FDA0002524614090000044
using formulas
Figure FDA0002524614090000045
Obtaining the constant pressure specific heat capacity of wet flue gas at the inlet of the low-temperature economizer, wherein Cp.sy.1vThe constant pressure specific heat capacity of the wet flue gas at the outlet of the low-temperature economizer, Cp.H2OIs the specific heat capacity of the water vapor at the outlet of the low-temperature economizer at constant pressure
Figure FDA0002524614090000046
9. The method for measuring the draught fan inlet flue gas flow according to claim 6, wherein the fourth step comprises:
using formulas
Figure FDA0002524614090000047
Obtaining the enthalpy of the smoke reduced by the low-temperature economizer, wherein, Delta HsyEnthalpy of flue gas reduced by low-temperature economizer, Bfg.NThe flow rate of the smoke at the inlet of the induced draft fan is in a standard state;
using formulas
Figure FDA0002524614090000048
Obtaining the enthalpy of the heating medium water increased by the low-temperature economizer, wherein, Delta HwEnthalpy added for hot media water passing through low-temperature economizer, BwIs the water flow of the water inlet pipeline of the low-temperature economizer, Cw.enIs the specific heat capacity at the water temperature of the water inlet pipeline of the low-temperature economizer, Cw.lvThe specific heat capacity of the water temperature of the water outlet pipeline of the low-temperature economizer is obtained;
from heat balance Δ Hsy＝ΔHwCan obtain the smoke flow at the inlet of the induced draft fan under the standard state
Figure FDA0002524614090000051
10. The method for measuring the draught fan inlet flue gas flow according to claim 6, wherein the fifth step comprises:
collecting static pressure of inlet flue gas of the induced draft fan, and acquiring real-time inlet flue gas flow of the induced draft fan according to the static pressure of the inlet flue gas of the induced draft fan and the inlet flue gas flow of the induced draft fan in a standard state
Figure FDA0002524614090000052
Wherein, BfgFor real-time draught fan inlet flue gas flow, PfgIs the static pressure of the smoke at the inlet of the draught fan.
CN202010500474.8A 2020-06-04 2020-06-04 Draught fan inlet flue gas flow measuring device and method Pending CN111521226A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115032330A (en) * 2021-12-28 2022-09-09 大连亚泰科技新材料股份有限公司 Testing machine for testing desulfurization effect of desulfurizing agent

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115032330A (en) * 2021-12-28 2022-09-09 大连亚泰科技新材料股份有限公司 Testing machine for testing desulfurization effect of desulfurizing agent
CN115032330B (en) * 2021-12-28 2023-08-04 大连亚泰科技新材料股份有限公司 Desulfurizing agent desulfurization effect detection testing machine

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