GB/T 13931-2017Electrostatic precipitator - Methods of performance tests (English PDF)

4.1 Dust removal efficiency test

4.1.1 Overview At the same time, the dust concentration of the flue gas at the inlet and outlet of the electrostatic precipitator and the air leakage rate of the main body of the electrostatic precipitator are tested, and the dust removal efficiency is obtained through calculation.

4.1.2 Provisions for sampling position, sampling hole and sampling point

4.1.2.1 Sampling position The sampling position should be selected in the straight pipe section where the airflow is stable, and other interference sources such as elbows and reducers are more than 6 times equivalent diameter in the downstream direction. The upstream direction is greater than 3 equivalents in diameter. When selecting a position, the vertical pipe section should be given priority. When the length of the flue cannot meet the above requirements, it can be rooted. According to the actual situation, a relatively suitable pipe segment is selected as the sampling position.

4.1.2.2 Sampling hole The size of the sampling hole should be sufficient to insert the largest sampling device into the flue. The short tube of the orifice should not be too long, and the structure of the sampling hole can be determined by itself.

4.1.2.3 Number of sampling points 4.1.2.3.1 Circular flue On the selected test section, set two sampling holes perpendicular to each other, and then divide the flue section into a certain number of concentric circles. Ring, through the sampling hole along the diameter direction of the section, take 4 points on each of the equal area rings as sampling points, as shown in Figure 1. Figure

1 Circular flue sampling point The number of sampling points is determined according to Table 1. Table

1 Circular ring and other area ring and sampling points Flue diameter/m number of sampling points (total of two holes) D<=1 1 \u003cd<=2 2 \u003cd<=3 3 \u003cd<=5 5 \u003cd<=7 1~2 2~3 3~4 4~5 5~6 4~8 8~12 12~16 16~20 20~ 24

Note. When the diameter d of the flue exceeds 7m, it is calculated as not less than 4m2 per ring area. The distance between each sampling point from the center of the flue is calculated according to formula (1). Ri=R× 2i-1 2n (1) In the formula. Ri

--- the distance of the sampling point from the center of the flue, in meters (m); R

--- flue radius, in meters (m); i

--- the sequence number of the sampling point from the center of the flue; n

--- The number of rings divided. The position of the sampling point can be expressed by the distance of the sampling point from the inner wall of the flue. See the multiple of the diameter of the flue from the inlet end of the sampling hole to each sampling point. Table 2. Table

2 Flue diameter multiple of the sampling point from the inner wall of the flue Sampling point number Ring number 0.146 0.854 0.067 0.250 0.750 0.933 0.044 0.146 0.294 0.706 0.854 0.956 0.033 0.105 0.195 0.321 0.679 0.805 0.895 0.967 0.022 0.082 0.145 0.227 0.344 0.656 0.773 0.855 0.918 0.978 4.1.2.3.2 Rectangular flue Divide the flue section into a number of small rectangles of equal area, so that the ratio of the adjacent sides of the small rectangle is close to 1, and the center of each small rectangle is Samples, as shown in Figure 2. Figure

2 Location of rectangular flue sampling points (N, n are the number of rows and columns of sampling points respectively) The number of sampling points is determined according to Table 3. Table

3 Rectangular flue sampling points Flue stop area A/m2 equal area small rectangle number of sampling points A<=1 1 \u003cA<=4 4 \u003cA<=9 9 \u003cA<=16 16 \u003cA<=20 20 \u003cA<=24 2×2 3×3 3×4 4×4 4×5 5× 5

Note. When the flue cross-sectional area A is greater than 24m2, the length of the small rectangle is less than 1m.

4.1.4 Sampling method

4.1.4.1 Predictive flow rate method for constant velocity sampling 4.1.4.1.1 Test equipment. ordinary type smoke tester, ordinary type sampling tube. 4.1.4.1.2 Test method. pre-measure the flue gas flow rate at each sampling point in the flue, and then according to this flow rate and the selected sample nozzle diameter, Calculate the sampling flow required for each point at constant speed, and then sample at each measurement point according to the calculated flow. See the forecasting flow rate sampling system image 3. Description. 1

--- regulating valve; 2

---sampling tube; 8

--- cumulative flow meter; 4

---thermometer; 10

---rotor flowmeter; 5

---temperature gauge; 11

---vacuum pressure gauge; Figure

4.1.6 Sampling calculation method

4.1.6.1 Calculation of sampling volume The sampling volume is calculated according to formula (2). Vsnd=0.0027Vm× Pa pr 273 Tr (2) In the formula. Vsnd

---the sampling volume of dry flue gas under standard conditions, in liters (L); Vm

--- the sampling volume of dry flue gas under actual working conditions, the unit is liter (L); Pa

--- local atmospheric pressure, the unit is Pascal (Pa); Pr

--- the flue gas pressure before the flow meter, the unit is Pascal (Pa); Tr

--- Flue gas temperature before the flow meter, in degrees Celsius (°C).

4.1.6.2 Calculation of dust concentration of flue gas The dust concentration of the flue gas is calculated according to formula (3) and formula (4). c= Vsnd× 103 (3) In the formula. c

--- The dust concentration of dry flue gas under standard conditions, in milligrams per cubic meter (mg/m3); m

--- the amount of dust collected in milligrams (mg); Vsnd

---the sampling volume of dry flue gas under standard conditions, in liters (L). m=m2-m1 (4) In the formula. m

--- the amount of dust collected in milligrams (mg); M2

---The quality of the filter cartridge after sampling, in milligrams (mg); M1

---The mass of the filter cartridge before sampling, in milligrams (mg).

4.1.6.3 Calculation of dust removal efficiency Dust removal efficiency is calculated by concentration method or gravimetric method.

4.2 Body Pressure Drop Test

4.2.1 Test location The test position should be as close as possible to the inlet and outlet of the electrostatic precipitator. Select a straight pipe section with an equivalent diameter of 1 inch from the inlet and outlet of the electrostatic precipitator. on. If the objective conditions are not allowed, the efficiency hole test can also be used, but the pressure drop of some flue should be deducted from the test data.

4.2.2 Arrangement of measuring points and number of measuring points Execute as specified in 4.1.2.

4.2.3 Test equipment Pitot tube, micro pressure gauge, U-type pressure gauge.

4.2.4 Test method Test the section on both sides of the inlet and outlet of the electrostatic precipitator and test the full pressure at each point, and measure the density of the atmosphere and the gas passing through the electrostatic precipitator. Then calculate according to formula (7) and formula (8). Deltap=pin-pout pH (7) In the formula. Deltap

--- pressure drop in Pascal (Pa); Pin

--- the total pressure of the inlet section, the unit is Pascal (Pa); Pout

--- the average pressure of the exit section, in Pascal (Pa); pH

--- Correction of buoyancy of high temperature gas in Pascal (Pa). pH=(rhoa-rho)gH (8) In the formula. pH

--- correction value of high temperature gas buoyancy in Pascal (Pa); Rhoa

--- atmospheric density in kilograms per cubic meter (kg/m3); rho

--- the density of gas passing through the electrostatic precipitator in kilograms per cubic meter (kg/m3); g

--- gravitational acceleration in meters per square second (m/s2); H

--- Height difference of the entrance and exit test position, in meters (m).

4.3 Body air leakage rate test

4.3.1 Test location Performed in accordance with 4.2.1.

4.3.2 Arrangement of measuring points and number of measuring points Execute as specified in 4.1.2.

4.3.3 Test equipment The electrochemical oxygen meter has an accuracy of not less than grade 1; a pitot tube and a micromanometer.

4.3.4 Test method For the test of the air leakage rate of the main body, the following two methods are mainly used.

a) Using the oxygen balance method, that is, testing the oxygen content in the flue gas at the inlet and outlet sections of the electrostatic precipitator, and calculating by formula (9). Deltaalpha= O2out-O2in 21-O2out × 100% (9) In the formula. Deltaalpha

--- electric precipitator air leakage rate, expressed in %; O2out

---the average oxygen content of the flue gas at the exit section of the electrostatic precipitator, expressed in %; O2in

--- The average oxygen content of the flue gas in the inlet section of the electrostatic precipitator is expressed in %.

b) Test the pneumatic pressure of the inlet and outlet of the electrostatic precipitator, and find the flow of flue gas at both ends of the inlet and outlet, and then calculate by formula (10). Deltaalpha= Qvout-qvin Qvin × 100% (10) In the formula. Deltaalpha

--- electric precipitator air leakage rate, expressed in %; Qvout

---The output of the standard dry smoke of the electrostatic precipitator, the unit is cubic meters per hour (m3/h); Qvin

--- Electrostatic precipitator imports the standard dry smoke volume, the unit is cubic meters per hour (m3/h).

4.4.1 Measurement method

4.4.1.1 Test equipment Three-phase active energy meter.

4.4.1.2 Test method Install the three-phase active energy meter at the dust removal and output bus of the electrostatic precipitator. According to the meter reading and measurement time before and after the measurement, Calculate the power consumption P (unit. kW) of the electric precipitator, and calculate it according to formula (11). P= W2-W1 (11) In the formula. W2

---Measure the reading of the electric energy meter in kilowatt-hours (kW·h); W1

---Measure the reading of the electric energy meter before the unit is kilowatt-hour (kW·h); t

--- Measurement time in hours (h). There is any objection to the test results, whichever is the measurement method.

4.4.2 Calculation method According to the primary current, voltage and power factor, meter reading, the power consumption of high and low voltage equipment (unit. kW) can be calculated. The high pressure part is calculated according to formula (12) and formula (13). Single phase (power frequency). Phv=sum i=1 (I1i×U1i×cosphi×10-3) (12) Three-phase (high frequency). Phv=sum i=1 (3×I1i×U1i×cosphi×10-3)(13) In the formula. Phv

--- power consumption of high voltage power supply equipment, in kilowatts (kW); I1i

--- primary current in amps (A); U1i

--- primary voltage in volts (V); n

--- number of electric fields; Cosphi

---power factor (

0.7 for power frequency power supply and

0.9 for high frequency power supply). The low-voltage rapping part is calculated according to formula (14). Pr= 3×Ir×U3a×cosphi×10-3 (14) In the formula. Pr

--- low-voltage rapping equipment power consumption, in kilowatts (kW); Ir

4.5 Flue gas flow rate and smoke flow test

4.5.1 Test position and measuring point Execute as specified in 4.1.2.

4.5.2 Test equipment Pitot tube, tilt micromanometer or electronic micromanometer. Pitot tube. it should be calibrated in the standard wind tunnel, the calibration coefficient can be measured before it can be used for measurement, and the standard pitot tube requires its calibration system. The number is 1±0.01, and the back-type pitot tube requires a correction factor of 0.84±0.01. Micro-pressure gauge. the accuracy of the tilting micro-pressure gauge should be no less than 2%, and the minimum graduation value should be no more than 2Pa, such as the fluctuation of the liquid column up and down during the test. Large, the average value of the reading; the accuracy of the electronic micro-pressure gauge is not less than 1%, such as the micro-pressure gauge reading jumps larger during the test, the reading is flat Mean.

4.5.3 Test method Test the parameters of the pneumatic pressure, static pressure and temperature in the flue, calculate the flue gas flow rate, and calculate the flue gas volume. Test the smoke pneumatic pressure The connection method is shown in Figure 7. Description. 1

---standard pitot tube; 3

---inclined tube micromanometer; 4

---back type pitot tube. Figure 7 smoke pneumatic pressure test system

4.5.4 Calculation method The average flow rate is calculated according to equations (17) and (18). Us=0.0766Kp 273 ts× pd (17) In the formula. Us

--- The average flow rate of smoke, in meters per second (m/s); Kp

--- pitot tube correction factor; Ts

--- flue gas temperature in degrees Celsius (°C); Pd

--- smoke pneumatic square root average, calculated according to formula (18). Pd = Pd1 pd2 pd3 pdn (18) In the formula. Pd

---the average value of the square root of the smoke pneumatic pressure; Pdi

--- measured value of dynamic pressure (i = 1, 2,,

n) of each measuring point, the unit is Pascal (Pa); n