Reference method for measuring releases of particulate from stationary sources: method E


Method E: Determination of Particulate Releases

5.1 Applicability

This method is used to measure the mass concentration and mass emission or release of particulate matter from enclosed gas streams of stationary sources.

Direct application of the procedures specified in this method may be limited by one or more of the following conditions:

  • sample locations less than two stack diameters downstream or less than 0.5 stack diameter upstream of a flow disturbance;

  • duct cross-sectional areas less than 0.071 m2 (113 in2) or duct diameters less than 0.3 m (12 in);

  • supersaturated gas streams with entrained liquid droplets;

  • gas stream flow rates less than 3 m/s (10 ft/s) or greater than 30 m/s (100 ft/s);

  • excessively high stack gas temperature that may cause damage to the sampling equipment even with the use of a water-cooled probe;

  • gas streams containing corrosive or unstable components;

  • cyclonic flow patterns within the gas stream; or

  • rapid fluctuations in velocity, particulate loading, and/or temperature of the gas stream due to uncontrollable process variations.

For compliance testing, possible modifications to allow sampling of sources exhibiting any of these characteristics may be approved in writing by the Minister of the Environment.

5.2 Principle

Particulate matter is withdrawn isokinetically from a number of sampling or traverse points in an enclosed gas stream. The particulate sample is collected in the nozzle, probe, cyclone (see Section 1.3), and on a glass fibre filter, all maintained at a temperature of 120 ± 14°C (248 ± 25°F) or at such other temperature as is necessary to prevent blinding of the filter from condensation. The particulate weight is determined gravimetrically after removal of uncombined water. Simultaneous determinations of the gas stream moisture content, velocity, temperature, and molecular weight allow calculations of the particulate concentration and the particulate mass emission or release rate to be made.

Sampling isokinetically means that the linear velocity of the gas entering the sampling nozzle is equal to that of the undisturbed gas stream at the sampling point.

5.3 Apparatus

5.3.1 Sample Collection (Figure E-1)

The following items are required for sample collection:

Nozzle
A button-hook type nozzle with sharp, tapered leading edges. The nozzle is usually made of 316 stainless steel or Incoloy 825, but quartz or other inert material may be used when high temperature or corrosive gases are encountered. The minimum inside diameter of the nozzle shall be 4.76 mm (3/16 in) and shall be determined using calipers.

Probe
A Pyrex or quartz glass liner. Where length or strength limitations preclude the use of a glass liner, a seamless tubing made from an inert and corrosion-resistant material such as 316 stainless steel, Incoloy 825 or Teflon may be used. The liner is encased in a stainless-steel tube with a heating and temperature indicating system capable of maintaining the exit gas temperature at 120 ± 14°C (248 ± 25°F), or at such a temperature necessary to prevent condensation. A water-cooled probe should be used when very hot gases capable of damaging the nozzle/probe assembly are encountered.

Pitot Tube
An S-type (Stausscheibe) picot tube attached to the probe. The face openings of the pitot tube and the probe nozzle shall be adjacent and parallel to each other. The configuration of the probe assembly (pitot tube, nozzle, and thermocouple) is specified in Method B. The probe assembly shall be calibrated according to the calibration procedures specified in Method F.

Stack Temperature Sensor
A calibrated thermocouple or other suitable temperature sensor capable of measuring the stack temperature to within 1.5% of the minimum absolute stack temperature. To minimize aerodynamic interaction, the pitot tube, thermocouple, and probe should be configured as specified in Method B. When high temperature gases are encountered, appropriate shielding and aspiration should be provided for the thermocouple to avoid heat radiation effects.

Cyclone (Optional)
A miniature Pyrex cyclone following the sampling probe and preceding the filter is to be used if premature buildup of particulate matter on the filter medium is anticipated. The cyclone is located inside the filter compartment and is, therefore, maintained at the same temperature as the filter.

Filter Holder
A Pyrex filter holder with a porous, fritted glass filter support and a silicone rubber gasket. The filter support may also be made of stainless steel, Teflon, or other inert and corrosion-resistant material. The filter holder is located inside the filter compartment.

Filter Compartment Heating System
A heating system capable of maintaining the temperature in the filter holder compartment at 120 ± 14°C (248 ± 25°F) or at such other temperature as is necessary to prevent blinding of the filter from condensation. A thermocouple or other temperature sensor is also required to measure the compartment temperature to within 3°C (5°F).

Impingers
Four Greenburg-Smith impingers are connected in series. The first, third, and fourth impingers are modified by replacing the tips and impaction plates of the standard design with a 13 mm (0.5 in) ID glass tube extending to within 13 mm (0.5 in) of the bottom of the impinger. The second impinger has the standard tip and impaction plate. The impingers are contained in an ice bath during sampling. The impingers may be replaced by any other suitable condenser providing that the condensed liquid is to be used for moisture determination only. A temperature sensor capable of measuring to within 1°C (2°F) shall be placed at the outlet of the last impinger.

Vacuum Pump
A leakless vacuum pump capable of maintaining an isokinetic sampling rate while continuously withdrawing a portion of the stack gases through the sampling train. The pump intake vacuum is measured to within (13 mm Hg) (0.5 in Hg) by a vacuum gauge attached to the vacuum line connecting the pump to the last impinger outlet. The sample flow rate is controlled by a combination of the coarse and fine flow control valves.

Metering System
A calibrated dry gas meter with inlet and outlet temperature sensors, or one that is temperature-compensated. The meter shall be calibrated according to the procedures specified in Method F. The temperature sensors must be capable of measuring the temperature to within 3°C (5°F).

Orifice
A calibrated orifice connected to the outlet of the dry gas meter. The orifice shall be calibrated according to the procedure specified in Method F.

Differential Pressure Indicators
The devices, such as inclined manometers, must be capable of measuring the pitot tube velocity pressure and the pressure drop across the orifice to within 0.1 mm (0.005 in) H 2O on the 0 to 25 mm (0 to 1 in) H 2O scale, and 1 mm (0.05 in) H 2O on the 25 to 250 mm (1 to 10 in) H 2O scale. The devices must be calibrated against a primary standard prior to the test.

Barometer
A barometer capable of measuring atmospheric pressure to within 2.5 mm Hg (0.1 inch Hg). The device must be calibrated against a primary standard prior to the test. Alternatively, the uncorrected atmospheric pressure provided by the local weather office may be used with an adjustment for the elevation of the sampling site. Deduct (2.5 mm Hg) per 30.5 m of elevation increase or add (2.5 mm Hg) per 30.5 m of elevation decrease.

Figure E-1: Particulate Sampling Train

Particulate Sampling Train

5.3.2 Sample Recovery

The following items are required for sample recovery:

Probe Brush
A nylon bristle brush of a length and diameter suitable for cleaning the probe.

Balances
An analytical balance capable of measuring to within ± 0.1 mg or less and a trip or top loading balance capable of measuring to within ± 0.5 g or better.

Miscellaneous
Wash bottles, sufficient quantity of sample containers large enough to hold all washings and a petri dish for holding the filter sample. All items shall be made of material such as glass, Teflon, or polypropylene which are chemically inert to both the samples and the reagents used for sample recovery.

5.4 Reagents and Materials

All chemicals used shall be reagent grade. The quality of the distilled or deionized water shall conform to specifications for Type III water given by the ASTM(1).

5.4.1 Sample Collection

The following items are required for sample collection:

Filter
A flash-fired glass fibre filter (organic binder removed) of a diameter compatible with the filter holder and capable of efficiently retaining particles as small as 0.3 μm in accordance with ASTM Standard D2986-71 (2). The filter material must be chemically inert to stack gas components such as sulphur dioxide (S0 2). Depending on the nature of the source and the analysis required, other types of filter media may be used, subject to Environment Canada approval. The filter must be desiccated to a constant weight before being used *. Place the pre-weighed filter in a clean container to prevent contamination during transportation to the sampling site.

* To Desiccate a filter to a Constant Weight

Label and desiccate the filter for at least 24 hours using silica gel or equivalent at 20 ± 6°C (68 ± 10°F). Weigh the filter to the nearest 0.1 mg at intervals of six hours or more in a room where the relative humidity is 50% or less. The weighing must be completed within two minutes after the filter is removed from the desiccator. The constant weight is attained when the difference between two consecutive readings is less than 0,5 mg.

Miscellaneous
Distilled or deionized water, crushed ice, heat-stable silicone stopcock grease, and indicating-type 6-16 mesh silica gel that has been dried at 180°C (350°F) for two hours.

5.4.2 Sample Recovery

The following items are required for sample recovery:

Acetone
Reagent grade acetone with low residue (<0.001 percent by weight).

Water
Distilled or deionized water.

5.5 Procedure

5.5.1 Sample Collection

Preliminary

Select the sampling site and the minimum number of traverse points according to procedures described in Method A. In the absence of any previous knowledge of the stack variables, a preliminary test should be conducted to obtain the following data:

  1. Velocity profile across the stack (Method B)

  2. Stack temperature and pressure (Method B)

  3. Stack gas molecular weight (Method C)

  4. Stack gas moisture content (Method D)

Use the data to determine the largest nozzle size possible for isokinetic sampling. Recommended minimum nozzle size is 4.76 mm (3/16 in) ID.

Select a total sampling time so that the sampling time per traverse point is equal to or greater than five minutes. The sample should be taken over a continuous process operating period. The purpose of the test will determine the sample volume to be collected.

Sampling Train Preparation

Prepare the sampling train in a clean area to minimize contamination. Install the selected size nozzle on the probe. Mark the probe with heat-resistant tape to denote the location of each, sampling point. Use a pair of tweezers to place the labelled and pre-weighed filter in the filter holder. Place a known volume (approximately 100 mL) of deionized or distilled water in each of the first two impingers, leave the third impinger empty and place a known amount (approximately 200 g) of silica gel in the fourth. Record the volume or weight (to the nearest 0.5 mL or 0.5 g) of the content of each impinger on the Moisture Analysis Data Sheet (Figure E-2). Set up the sampling train as in Figure E-1. Adjust the filter compartment and probe heating systems to maintain a temperature of 120 ± 14°C (248 ± 25°F) or such other temperature as is necessary to prevent blinding of the filter due to condensation. In the presence of an acidic gas, such as SO2 in the source, both temperatures shall be maintained above the acid dew point of the gas stream.

Figure E-2: Moisture Analysis Data Sheet

Moisture Analysis Data Sheet

Conduct a mandatory pre-test leak check of the sampling train by plugging the nozzle inlet and pulling a vacuum of 380 mm Hg (15 in, Hg) for at least one minute. The leakage rate must be less than 0.57 L/min (0.02 ft3/min) or 4% of the estimated average sampling rate, whichever is less. Sampling cannot proceed until the leakage rate is acceptable. Record the actual leakage rate on the Particulate Sampling Data Sheet (Figure E-3). Place crushed ice and water in the impinger box before sampling.

Figure E-3: Particulate Sampling Data Sheet

Click to enlarge

Particulate Sampling Data Sheet
Sampling Train Operation

To begin sampling, point the nozzle directly into the gas stream at the first traverse point. Using a nomograph or a programmable calculator, determine the orifice setting for isokinetic sampling. Immediately start the vacuum pump and adjust the sampling flow rate to isokinetic conditions. Sample for at least five minutes at each traverse point, the sampling time being the same for every point. Traverse the stack cross section and maintain isokinetic sampling throughout the test. Add more ice and water to the impinger box, as required, to maintain the temperature of the last impinger exit in the range of 0° to 20°C (32° to 68°F).

Record instrumentation readings on the Particulate Sampling Data Sheet (Figure E-3) every five minutes, or at regular intervals that are consistent with the sampling duration established for each point, whichever is less. (For example: Five minutes of sample per traverse point will require readings being recorded every five minutes; six minutes per point, every three minutes; eight minutes per point, every four minutes; etc.) Readings must also be taken before and after a leak check and when sampling is halted.

When it is necessary to halt sampling temporarily, either to dismantle the sampling train during port changeover or to change a train component, turn off the pump and immediately withdraw the probe from the stack. Conduct a mandatory leak check on the sampling train by plugging the nozzle and pulling a vacuum equal to or greater than the maximum value observed during sampling. Record the actual leakage rate. If the leakage rate exceeds 0.57 L/min (0.02 ft3/min) or 4% of the sampling flow rate, the test is invalid. If the leakage rate is acceptable, proceed with dismantling the sampling train or changing the train component. Before continuing with the test, conduct a mandatory leak check on the assembled train by following the pre-test leak check procedures used during sampling train preparation.

When the test is completed, conduct a mandatory post-test leak check on the sampling train by plugging the nozzle and pulling a vacuum equal to or greater than the maximum value observed during sampling. Record the actual leakage rate which must be less than 0.57 L/min (0.02 ft3/min) or 4% of the sampling flow rate, whichever is less. If the leakage rate is acceptable, proceed with recovering the samples.

5.5.2 Sample Recovery

Disconnect the probe from the sampling train. Seal all openings. Exercise care in moving the train components from the test site to the sample recovery area to minimize the loss of collected sample or the gain of extraneous particulate matter. Partition the train samples as follows:

Filter (Container No. 1)

Use a pair of clean tweezers or a sharp knife to transfer the filter and any loose material adhering to the filter support into a petri dish. Label and seal the sample container.

Nozzle, Probe Liner, Cyclone (if used), and Front-half of Filter-holder (Container No. 2)

Wash and brush the interior surfaces of the nozzle and probe with acetone. Place these washings into Container No. 2. Use acetone together with a brush or a rubber policeman to clean the inside surfaces of the cyclone (if used) and the front-half of the filter holder. Collect the acetone washings into Container No. 2. Seal and label the container and mark the liquid level.

Acetone Blank (Container No. 3)

Place a known volume (approximately equal to that in Container No. 2) of acetone, taken directly from the wash bottle being used, into Container No. 3. Seal the sample container and label it "acetone blank". Mark the liquid level.

Impingers (Container No. 4)

Measure the volume or weight (to the nearest 0.5 mL or 0.5 g) of the content of each impinger and record the results on the Moisture Analysis Data Sheet (Figure E-2). If chemical analysis of the impinger liquid is required, transfer the contents of the first three impingers to Container No. 4. Rinse the inside surfaces of these impingers, all connectors, and the back-half of the filter holder with deionized or distilled water into the same sample container. Seal and label the container and mark the liquid level. Discard the spent silica gel.

5.5.3 Sample Analysis

All analyses shall be performed in a clean laboratory equipped with a fume hood. The relative humidity of the room in which weighing is performed should be maintained at or below 50%.

Container No. 1 (Filter)

Transfer the filter and any loose particulate matter and filter material from the sample container to a tared weighing dish. Desiccate the sample to a constant weight (see note in Subsection 5.4.1) and record the result to the nearest 0.1 mg on the Particulate Analytical Data Sheet (Figure E-4).

Figure E-4: Particulate Analytical Data Sheet

Particulate Analytical Data Sheet
Container No. 2 (Acetone Washings)

Note the liquid level in the container (see Section 5.5.2) and determine if leakage occurred during transport. If there is a loss of the sample, the test is invalid. Transfer the sample from Container No. 2 into a small (less than 250 mL) tared beaker and evaporate the acetone washings to dryness at room temperature and pressure. Desiccate the sample to a constant weight and record the result (to the nearest 0.1 mg) on the Particulate Analytical Data Sheet (Figure E-4).

Container No. 3 (Acetone Blank)

Note the liquid level and determine if leakage occurred during transport. Measure the volume of the acetone blank to the nearest 1 mL and enter the value on the Particulate Analytical Data Sheet (Figure E-4). Place the solution in a small tared beaker and evaporate the solution to dryness at room pressure and temperature (or at an elevated temperature using a steam bath). Desiccate the acetone blank sample to a constant weight. Enter the results to the nearest 0.1 mg in the Particulate Analytical Data Sheet (Figure E-4).

Container No. 4 (Impinger solution)

Note the liquid level and determine if leakage occurred during transport. Measure the volume of the solution to the nearest 1 mL and enter the value on the Particulate Analytical Data Sheet (Figure E-4). Perform chemical analysis on the impinger solutions as required.

5.6 Calculations

To simplify record keeping during a test, field data may be entered in the units for which the sampling equipment is designed. These values must be converted, if necessary, to the numeric units specified in the equations where they are used.

Volume of Stack Gas Sample

Correct the total sample volume measured by the dry gas meter to reference temperature and pressure conditions (25°C and 101.3 kPa) using Equation E-1.

Note: For a temperature-compensated dry gas meter, the average dry gas meter temperature, ( Tm )avg, should be substituted by a constant value as specified by the manufacturer.

Equation E-1

Volume of Stack Gas Samples Equation

Volume of Water Vapour

Calculate the volume of water vapour in the stack gas sample at reference temperature and pressure conditions using Equation E-2.

Equation E-2

Volume of Water Vapour Equation

Moisture Content of Stack Gas

Calculate the volumetric fraction of water vapour in the stack gas at reference conditions using Equation E-3.

Equation E-3

Moisture Content of Stack Gas Equation

For saturated or supersaturated stack gas, use a psychrometric chart to determine Bwo

Absolute Stack Gas Pressure

Calculate the absolute stack gas pressure using Equation E-4.

Equation E-4

Absolute stack gas pressure Equation

Stack Gas Molecular Weight

Calculate the stack gas molecular weight on a wet basis using Equation E-5.

Equation E-5

Stack Gas Molecular Weight Equation

Note: Use Equation C-2 or C-3 of Method C to calculate Md.

Stack Gas Velocity

Calculate the stack gas velocity measured at each traverse point using Equation E-6.

Equation E-6

Actual stack gas velocity Equation

Volumetric Stack Gas Flow Rate

Calculate the average volumetric flow rate of the stack gas on a dry basis and at reference conditions using Equation E-7.

Equation E-7

Average stack gas volumetric flow rate Equation

Weight of Particulate Sample

Determine the weight of the particulate sample, Wp, from the sum of the particulate weights obtained from Containers No. 1 and 2 less the weight of the residue in the acetone blank, as shown in the Particulate Analytical Data Sheet (Figure E-4).

Concentration of Particulate Matter

Calculate the concentration of particulate matter in the stack gas using Equation E-8.

Equation E-8

Concentration of Particulate Matter Equation

Mass Emission Rate

Calculate the mass emission or release rate of particulate matter using Equation E-9.

Equation E-9

Mass Emission Rates Equation

Isokineticity

Calculate the isokineticity for each traverse point using Equation E-10.

Equation E-10

Isokineticity Equation

A test shall be considered valid with respect to isokineticity (or isokinetic variation) providing that:

  1. 90% or more of the isokineticity values, I, calculated for all traverse points are within the range 90 to 110%, i.e., 90% ≤ I ≤ 110%; and

  2. the arithmetic average of all the isokineticity values is within the range 90 to 110%, i.e., 90% ≤ Iavg ≤ 110%.

5.7 Nomenclature

As
inside cross-sectional area of the stack, duct, or flue, m 2

Bwo
volumetric fraction of water vapour in the stack gas, dimensionless

Cp
S-type pitot tube coefficient, dimensionless

Cs
concentration of particulate matter in the stack gas on a dry basis at reference temperature and pressure conditions, mg/m 3

ERp
mass emission rate of particulate matter, kg/h

Δ Havg
average pressure drop across orifice meter, kPa

Δ H
pressure drop across orifice meter for each traverse point, kPa

Iavg
the arithmetic average of all the isokineticity values for the test, %

I
isokineticity i.e., the ratio of the sampling velocity through the nozzle to the velocity of the undisturbed gas stream at each traverse point, %

j
the jth traverse point, dimensionless

Md
molecular weight of stack gases on a dry basis, kg/kmol

Ms
molecular weight of stack gases on a wet basis, kg/kmol

MH2O
molecular weight of water, 18 kg/kmol

Nd
inside diameter of the sampling nozzle, mm

ps
absolute stack gas pressure, kPa

pbar
barometric pressure at the sampling site, kPa

Δ p
pitot tube velocity pressure reading at each traverse point, kPa

pref
reference pressure, 101.3 kPa

Δ ps
static pressure of the stack gases, kPa

Qs
volumetric stack gas flow rate on a dry basis at reference temperature and reference pressure conditions, m 3/h

R
universal gas constant, 8.31(kPa)(m 3)(kmol -1)(K -1)

t
sampling duration for each traverse point, min

Ts
stack gas temperature at each traverse point, K

(Ts)avg
arithmetic average of the stack gas temperatures, K

Tmi
temperature at the dry gas meter inlet for each traverse point, K

Tmo
temperature at the dry gas meter outlet for each traverse point, K

(Tm)avg
arithmetic average of the dry gas meter temperatures, K

Tref
reference temperature, 298 K

Us
stack gas velocity at each traverse point, m/s

(Us)avg
arithmetic average of the stack gas velocities, m/s

(Vw)ref
volume of water vapour in the stack gas sample at reference temperature and pressure conditions, m 3

Vm
volume of stack gas sample at dry gas meter conditions, m 3

(Vm)j
volume of stack gas sample at dry gas meter conditions for the jth traverse point, m 3

(Vm)ref
volume of stack gas sample at reference temperature and pressure conditions, m 3

WH2O
weight of water vapour condensed in the impingers, g

Wp
total weight of particulate samples collected during the test run, mg

γ
dry gas meter calibration factor (ratio of the wet test meter volume to the dry test meter volume), dimensionless

6×10-5
conversion factor, (m 2/mm 2)(s/min)

10-3
conversion factor, kg/g

10-6
conversion factor, kg/mg

128.95
dimensional constant (m/s) [(kg/kmol/K)] ½

3600
conversion factor, s/h (seconds/hour)
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