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standard conditions (70° F. and 29.92 inches Hg) by using equation 6–1.

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tilled water and add these washings to the same storage container.

4.3 Sample analysis. Transfer the contents of the storage container to a 50 ml. volumetric flask. Dilute to the mark with deionized, distilled water. Pipette a 10 ml. aliquot of this solution into a 125 ml. Erlenmeyer flask. Add 40 ml. of isopropanol and two to four drops of thorin indicator. Titrate to a pink endpoint using 0.01 N barium perchlorate. Run a blank with each series of samples.

5. Calibration.

5.1 Use standard methods and equipment which have been approved by the Administrator to calibrate the rotameter, pitot tube, dry gas meter, and probe heater.

5.2 Standardize the barium perchlorate against 25 ml. of standard sulfuric acid containing 100 ml. of isopropanol.

6. Calculations.

6.1 Dry gas volume. Correct the sample volume measured by the dry gas meter to

°R_/V „Pbar 17.71

in. Hg T I equation 6-1 where: Vmara= Volume of gas sample through the

dry gas meter (standard condi

tions), cu. ft. Vm= Volume of gas sample through the

dry gas meter (meter condi

tions), cu. ft. Tro= Absolute temperature at standard

conditions, 530° R.
Tm= Average dry gas meter temperature,

°R.
Phar= Barometric pressure at the orifice

meter, inches Hg.
Para= Absolute pressure at standard con-

ditions, 29.92 inches Hg. 6.2 Sulfur dioxide concentration.

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g.-ml.).

V
mgtd

equation 6-2 where:

METHOD 7--DETERMINATION OF NITROGEN OXIDE Cso,= Concentration of sulfur dioxide

EMISSIONS FROM STATIONARY SOURCES at standard conditions, dry basis, lb./cu. ft.

1. Principle and applicability. 7.05 X 10-5= Conversion factor, including the

1.1 Principle. A grab sample is collected number of grams per gram

in an evacuated flask containing a dilute equivalent of sulfur dioxide

sulfuric acid-hydrogen peroxide absorbing (32 g./g.-eq.), 453.6 g./lb., and

solution, and the nitrogen oxides, except 1,000 ml./1., lb.-1./g.-ml.

nitrous oxide, are measure colorimetrically V = Volume of barium perchlorate

using the phenoldisulfonic acid (PDS) titrant used for the sample,

procedure. ml.

1.2 Applicability. This method is applicaV.,= Volume of barium perchlorate

ble for the measurement of nitrogen oxides titrant used for the blank, ml.

from stationary sources only when specified N=Normality of barium perchlorate

by the test procedures for determining comtitrant, g.-eq./1.

pliance with New Source Performance Von=Total solution volume of sulfur

Standards. dioxide, 50 ml.

2. Apparatus. V = Volume of sample aliquot ti

2.1 Sampling. See Figure 7–1. trated, ml.

2.1.1 Probe-Pyrex1 glass, heated, with Vmsta=Volume of gas sample through

filter to remove particulate matter. Heating the dry gas meter (standard

is unnecessary if the probe remains dry durconditions), cu. ft., see Equa

ing the purging period. tion 6–1.

2.1.2 Collection flask—Two-liter, Pyrex, 7. References.

round bottom with short neck and 24/40 Atmospheric Emissions from Sulfuric Acid

standard taper opening, protected against

'mplosion or breakage. Manufacturing Processes, U.S. DHEW, PHS, Division of Air Pollution, Public Health Serv

2.1.3 Flask valve-T-bore stopcock conice Publication No. 999-AP-13, Cincinnati,

nected to a 24/40 standard taper joint.

2.1.4 Temperature gauge-Dial-type therOhio, 1965.

mometer, or equivalent, capable of measurCorbett, P. F., The Determination of so,

ing 2° F. intervals from 25° to 125° F. and so, in Flue Gases, Journal of the Insti

2.1.5 Vacuum line-Tubing capable of tute of Fuel, 24:237–243, 1961.

withstanding a vacuum of 3 inches Hg absoMatty, R. E. and E. K. Diehl, Measuring

uring lute pressure, with “T” connection and T-bore Flue-Gas So, and Soz, Power 101:94–97, No

stopcock, or equivalent. vember, 1957.

2.1.6 Pressure gauge--U-tube manometer, Patton, W. F. and J. A. Brink, Jr., New 36 inches, with 0.1-inch divisions, or Equipment and Techniques for Sampling

equivalent. Chemical Process Gases, J. Air Pollution Control Association, 13, 162 (1963).

1 Trade name.

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2.2.3. Glass wash bottle.
2.3 Analysis.
2.3.1 Steam bath.

2.3.2 Beakers or casseroles-250 ml., one for each sample and standard (blank).

2.3.3 Volumetric pipettes—1, 2, and 10 ml.

2.3.4 Transfer pipette-10 ml. with 0.1 ml. divisions.

2.3.5 Volumetric flask—100 ml., one for each sample, and 1,000 ml. for the standard (blank).

2.3.6 Spectrophotometer-To measure absorbance at 420 nm.

2.3.7 Graduated cylinder-100 ml. with 1.0 ml. divisions.

2.3.8 Analytical balance-To measure to 0.1 mg.

3. Reagents.
3.1 Sampling.

3.1.1 Absorbing solution-Add 2.8 ml. of concentrated H,SO, to i liter of distilled water. Mix well and add 6 ml. of 3 percent hydrogen peroxide. Prepare a fresh solution weekly and do not expose to extreme heat or direct sunlight.

3.2 Sample recovery.

3.2.1 Sodium hydroxide (1N)-Dissolve 40 g. NaOH in distilled water and dilute to 1 liter.

3.2.2 Red litmus paper.
3.2.3 Water-Deionized, distilled.

3.3 Analysis.

3.3.1 Fuming sulfuric acid-15 to 18% by weight free sulfur trioxide.

3.3.2 Phenol-White solid reagent grade.

3.3.3 Sulfuric acid-Concentrated reagent grade.

3.3.4 Standard solution-Dissolve 0.5495 g. potassium nitrate (KNO,) in distilled water and dilute to 1 liter. For the working stand. ard solution, dilute 10 ml. of the resulting solution to 100 ml. with distilled water. One ml. of the working standard solution is equivalent to 25 ug. nitrogen dioxide.

3.3.5 Water-Deionized, distilled.

3.3.6 Phenoldisulfonic acid solutionDissolve 25 g. of pure white phenol in 150 ml. concentrated sulfuric acid on a steam bath. Cool, add 75 ml. fuming sulfuric acid, and heat at 100° C. for 2 hours. Store in a dark, stoppered bottle.

4. Procedure. 4.1 Sampling.

4.1.1 Pipette 25 ml. of absorbing solution into a sample flask. Insert the flask valve stopper into the flask with the valve in the "purge" position. Assemble the sampling train as shown in Figure 7-1 and place the probe at the sampling point. Turn the flask valve and the pump valve to their "evacuate" positions. Evacuate the flask to at least 3 inches Hg absolute pressure. Turn the pump

valve to its “vent” position and turn off the water. Evaporate the solution to dryness on & pump. Check the manometer for any fluctu steam bath and then cool. Add 2 ml. phenolation in the mercury level. If there is a visi disulfonic acid solution to the dried residue ble change over the span of one minute, and triturate thoroughly with a glass rod. check for leaks. Record the initial volume, Make sure the solution contacts all the resitemperature, and barometric pressure. Turn due. Add 1 ml. distilled water and four drops the flask valve to its "purge" position, and of concentrated sulfuric acid. Heat the soluthen do the same with the pump valve. tion on a steam bath for 3 minutes with ocPurge the probe and the vacuum tube using casional stirring. Cool, add 20 ml. distilled the squeeze bulb. If condensation occurs in water, mix well by stirring, and add concenthe probe and flask valve area, beat the probe trated ammonium hydroxide dropwise with and purge until the condensation disappears. constant stirring until alkaline to litmus Then turn the pump valve to its "vent" posi- paper. Transfer the solution to a 100 ml. tion. Turn the flask valve to its "sample" volumetric flask and wash the beaker three position and allow sample to enter the flask times with 4 to 5 ml. portions of distilled for about 15 seconds. After collecting the water. Dilute to the mark and mix thorsample, turn the flask valve to its "purge" oughly. If the sample contains solids, transposition and disconnect the flask from the fer a portion of the solution to a clean, dry sampling train. Shake the flask for 5 centrifuge tube, and centrifuge, or filter & minutes.

portion of the solution. Measure the absorb4.2 Sample recovery.

ance of each sample at 420 nm. using the 4.2.1 Let the flask set for a minimum of blank solution as a zero. Dilute the sample 16 hours and then shake the contents for 2 and the blank with a suitable amount of minutes. Connect the flask to a mercury distilled water if absorbance falls outside the filled U-tube manometer, open the valve range of calibration. from the flask to the manometer, and record 5. Calibration. the flask pressure and temperature along 5.1 Flask volume, Assemble the flask and with the barometric pressure. Transfer the flask valve and fill with water to the stopflask contents to a container for shipment cock. Measure the volume of water to +10 or to a 250 ml. beaker for analysis. Rinse the ml. Number and record the volume on the flask with two portions of distilled water flask. (approximately 10 ml.) and add rinse water 5.2 Spectrophotometer. Add 0.0 to 16.0 ml. to the sample. For a blank use 25 ml. of ab of standard solution to a series of beakers. To sorbing solution and the same volume of dis each beaker add 25 ml. of absorbing solution tilled water as used in rinsing the flask. Prior

and add sodium hydroxide (1N) dropwise to shipping or analysis, add sodium hydrox

until alkaline to litmus paper (about 25 to ide (1N) dropwise into both the sample and

35 drops). Follow the analysis procedure of the blank until alkaline to litmus paper

section 4.3 to collect enough data to draw a (about 25 to 35 drops in each). 4.3 Analysis.

calibration curve of concentration in ug. NO: 4.3.1 If the sample has been shipped in per sample versus absorbance. a container, transfer the contents to a 250 6. Calculations. ml. beaker using a small amount of distilled 6.1 Sample volume. _Tota(V4-V2)

(P. Pil V,.=

Pord where:

P,=Final absolute pressure of flask,

inches Hg. V. = Sample volume at standard condi

P,= Initial absolute pressure of flask, tions (dry basis), ml.

inches Hg. Tod= Absolute temperature at standard T,=Final absolute temperature of flask,

°R conditions, 530° R.

T,=Initial absolute temperature of flask, P.,= Pressure at standard conditions,

°R. 29.92 inches Hg.

6.2 Sample concentration. Read ug. NO, V = Volume of flask and valve, ml. for each sample from the plot of ug. NO, V,= Volume of absorbing solution, 25 ml. versus absorbance.

1 lb.

cu. ft. C=(

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25 ml.) (

IT) Equation 7-1

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equation 7-2 where:

7. References. C=Concentration of No, as NO, (dry Standard Methods of Chemical Analysis. basis), lb./s.c.1.

6th ed. New York, D. Van Nostrand Co., Inc., m=Mass of No, in gas sample, ug.

1962, vol. 1, p. 329–330. V=Sample volume at standard condi Standard Method of Test for Oxides of tions (dry basis), ml.

Nitrogen in Gaseous Combustion Products

66-08872— 11

(Phenoldisulfonic Acid Procedure), In: 1968 Book of ASTM Standards, Part 23, Philadelphia, Pa. 1968, ASTM Designation D-1608-60, p. 725–729.

Jacob, M, B., The Chemical Analysis of Air Pollutants, New York, N.Y., Interscience Publishers, Inc., 1960, vol. 10, p. 351-356. METHOD 8—DETERMINATION OF SULFURIC ACID

MIST AND SULFUR DIOXIDE EMISSIONS FROM STATIONARY SOURCES 1. Principle and applicability.

1.1 Principle. A gas sample is extracted from a sampling point in the stack and the acid mist including sulfur trioxide is separated from sulfur dioxide. Both fractions are measured separately by the barium-thorin titration method.

1.2 Applicability. This method is applicable to determination of sulfuric acid mist (including sulfur trioxide) and sulfur dioxide from stationary sources only when specified by the test procedures for determining compliance with the New Source Performance Standards.

2. Apparatus.

2.1 Sampling. See Figure 8–1. Many of the design specifications of this sampling train are described in APTD-0581.

2.1.1 Nozzle-Stainless steel (316) with sharp, tapered leading edge.

2.1.2 Probe-Pyrex 1 glass with a heating system to prevent visible condensation during sampling.

2.1.3 Pitot tubeType S, or equivalent, attached to probe to monitor stack gas velocity.

2.1.4 Filter holder—Pyrex 1 glass.

2.1.5 Impingers-Four as shown in Figure 8-1. The first and third are of the GreenburgSmith design with standard tip. The second and fourth are of the Greenburg-Smith design, modified by replacing the standard tip with a 12-inch ID glass tube extending to one-half inch from the bottom of the impinger flask. Similar collection systems, which have been approved by the Administrator, may be used.

2.1.6 Metering system-Vacuum gauge, leak-free pump, thermometers capable of measuring temperature to within 5° F., dry gas meter with 2% accuracy, and related equipment, or equivalent, as required to maintain an isokinetic sampling rate and to determine sample volume.

2.1.7 Barometer-To measure atmospheric pressure to +0.1 inch Hg.

1 Trade name.

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2.2 Sample recovery.

4. Procedure. 2.2.1 Wash bottles-Two.

4.1 Sampling. 2.2.2 Graduated cylinders—250 ml., 500 4.1.1 After selecting the sampling site and ml.

the minimum number of sampling points, 2.2.3 Glass sample storage containers.

determine the stack pressure, temperature, 2.2.4 Graduated cylinder-250 ml.

moisture, and range of velocity head. 2.3 Analysis.

4.1.2 Preparation of collection train. 2.3.1 Pipette-25 ml., 100 ml.

Place 100 ml. of 80% isopropanol in the first 2.3.2 Burette-50 ml.

impinger, 100 ml. of 3% hydrogen peroxide in 2.3.3 Erlenmeyer flask—250 ml.

both the second and third impingers, and 2.3.4 Graduated cylinder-100 ml.

about 200 g. of silica gel in the fourth im2.3.5 Trip balance—300 g. capacity, topinger. Retain a portion of the reagents measure to +0.05 g.

use as blank solutions. Assemble the train 2.3.6 Dropping bottle-to add indicator

without the probe as shown in Figure 8-1 solution.

with the filter between the first and second 3. Reagents.

impingers. Leak check the sampling train 3.1 Sampling.

at the sampling site by plugging the inlet to 3.1.1 Filters—Glass fiber, MSA type 1106 the first impinger and pulling a 15-inch Hg BH, or equivalent, of a suitable size to fit vacuum. A leakage rate not in excess of 0.02 in the filter holder.

c.f.m. at a vacuum of 15 inches Hg is ac3.1.2 Silica gel-Indicating type, 6–16 ceptable. Attach the probe and turn on the mesh, dried at 175° C. (350° F.) for 2 hours. probe heating system. Adjust the probe 3.1.3 Water-Deionized, distilled.

heater setting during sampling to prevent 3.1.4 Isopropanol, 80%-Mix 800 ml. of any visible condensation, Place crushed ice isopropanol with 200 ml. of deionized, dis around the impingers. Add more ice during tilled water.

the run to keep the temperature of the gases 3.1.5 Hydrogen peroxide, 3%-Dilute 100 leaving the last impinger at 70° F. or less. ml. of 30% hydrogen peroxide to 1 liter with 4.1.3 Train operation. For each run, redeionized, distilled water.

cord the data required on the example sheet 3.1.6 Crushed ice.

shown in Figure 8–2. Take readings at each 3.2 Sample recovery.

sampling point at least every 5 minutes and 3.2.1 Water-Deionized, distilled.

when significant changes in stack conditions 3.2.2 Isopropanol, 80%.

necessitate additional adjustments in flow 3.3 Analysis.

rate. To begin sampling, position the nozzle 3.3.1 Water-Deionized, distilled.

at the first traverse point with the tip point3.3.2 Isopropanol.

ing directly into the gas stream. Start the 3.3.3 Thorin indicator-1-(0-arsonophen pump and immediately adjust the flow to ylazo)-2-naphthol-3, 6-disulfonic acid, di isokinetic conditions. Maintain isokinetic sodium salt (or equivalent). Dissolve 0.20 g. sampling throughout the sampling period. in 100 ml. distilled water.

Nomographs are available which aid in the 3.3.4 Barium perchlorate (0.01N)-Dis rapid adjustment of the sampling rate withsolve 1.95 g. of barium perchlorate (Ba out other computations. APTD-0576 details (CO2), 3 H,O) in 200 ml. distilled water and the procedure for using these nomographs. dilute to 1 liter with isopropanol. Standardize At the conclusion of each run, turn off the with sulfuric acid.

pump and record the final readings. Remove 3.3.5 Sulfuric acid standard (0.01N)— the probe from the stack and disconnect it Purchase or standardize to + 0.0002 N against from the train. Drain the ice bath and purge 0.01 N NaOH which has previously been the remaining part of the train by drawing standardized against primary standard po clean ambient air through the system for 15 tassium acid phthalate.

minutes.

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