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5.2 Analysis 5.2.1 Prepareda calibration curve for the spectrophotometer using the standard mercury solutions. Plot the peak heights read on the recorder versus the concentrations of mercury in the standard solutions. Standards should be interspersed with the samples since the calibration can change slightly with time. A new calibration curve should be prepared for each new set of samples run.

6. Calculations.-6.1 Average dry gas meter temperature, stack temperature, stack pressure and average orifice pressure drop. See data sheet (fig. 101-6).

6.2 Dry gas volume.-Correct the sample volume measured by the dry gas meter to stack conditions by using equation 101-2.

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FINAL

INITIAL

LIQUID COLLECTED

TOTAL VOLUME COLLECTED

VOLUME,

ml

SILICA GEL WEIGHT, 9

ml

CONVERT WEIGHT OF WATER TO VOLUME BY dividing total weight

INCREASE BY DENSITY OF WATER. 11 g/ml):

INCREASE. VOLUME WATER, ml (1 g/ml)

Figure 101-7. Analytical data.

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Pitot tube coefficient, dimensionless. (T). Average stack gas temperature, R. (VAP). Average square root of the velocity head of stack gas (in. H2O)1 (see fig. 101-8). P. Stack pressure, Pbar+static pressure, in. Hg. M. Molecular weight of stack gas (wet basis), the summation of the products of the molecular weight of each component multiplied by its volumetric proportion in the mixture, lb./lb. mole.

Figure 101-8 shows a sample recording sheet for velocity traverse data. Use the averages in the last two columns of figure 101-8 to determine the average stack gas velocity from equation 101-5.

6.6 Mercury collected. Calculate the total weight of mercury collected by using equation 101-6.

where:

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W1=VICI-VoCo (+V1Ct) __eq. 101-6

W total weight of mercury collected, ug. V=Total volume of condensed moisture and ICI in sample bottle, ml. C1=Concentration of mercury measured in sample bottle, μg/ml. V=Total volume of IC1 used in sampling (impinger contents and all wash amounts), ml.

Co=Blank concentration of mercury in ICI solution, μg/ml.

V=Total volume of ICI used in filter bottle (if used), ml.

C=Concentration of mercury in filter bottle (if used), μg/ml.

6.7 Total mercury emission. Calculate the total amount of mercury emitted from each stack per day by equation 101-7. This equation is applicable for continuous operations. For cyclic operations, use only the time per day each stack is in operation. The total mercury emissions from a source will be the summation of results from all stacks.

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(v.). Average stack gas velocity, feet per second.

7. Evaluation of results-7.1 tion of compliance.-7.1.1

DeterminaEach performance

test shall consist of three repetitions of the applicable test method. For the purpose of determining compliance with an applicable national emission standard, the average of results of all repetitions shall apply.

7.2 Acceptable isokinetic results.-7.2.1 The following range sets the limit on acceptable isokinetic sampling results:

If 90% ≤1≤110%, the results are acceptable; otherwise, reject the test and repeat.

8. References.-1. Addendum to Specifications for Incinerator Testing at Federal Facilities, PHS, NCAPC, Dec. 6, 1967.

2. Determining Dust Concentration in a Gas Stream, ASME Performance Test Code No. 27, New York, N.Y., 1957.

3. Devorkin, Howard, et al., Air Pollution Source Testing Manual, Air Pollution Control District, Los Angeles, Calif., Nov. 1963.

4. Hatch, W. R. and W. L. Ott, "Determination of Sub-Microgram Quantities of Mercury by Atomic Absorption Spectrophotometry," Anal. Chem., 40:2085-87, 1968.

5. Mark, L. S., Mechanical Engineers' Handbook, McGraw-Hill Book Co., Inc., New York, N.Y., 1951.

6. Martin, Robert M., Construction Details of Isokinetic Source Sampling Equipment, Environmental Protection Agency, APTD

0581.

7. Methods for Determination of Velocity, Volume, Dust and Mist Content of Gases, Western Precipitation Division of Joy Mfg. Co., Los Angeles, Calif. Bul. WP-50, 1968.

8. Perry, J. H., Chemical Engineers' Handbook, McGraw-Hill Book Co., Inc., New York, N.Y., 1960.

9. Rom, Jerome J., Maintenance, Calibration, and Operation of Isokinetic Source Sampling Equipment, Environmental Protection Agency, APTD-0576.

10. Shigehara, R. T., W. F. Todd, and W. S. Smith, Significance of Errors in Stack Sampling Measurements, Paper presented at the Annual Meeting of the Air Pollution Control Association, St. Louis, Mo., June 14-19, 1970.

11. Smith, W. S., et al., Stack Gas Sampling Improved and Simplified with New Equipment, APCA paper No. 67-119, 1967.

12. Smith, W. S., R. T. Shigehara, and W. F. Todd, A Method of Interpreting Stack Sampling Data, Paper presented at the 63d Annual Meeting of the Air Pollution Control Association, St. Louis, Mo., June 14-19, 1970. 13. Specifications for Incinerator Testing at Federal Facilities PHS, NCAPC, 1967.

14. Standard Method for Sampling Stacks for Particulate Matter, In: 1971 Book of ASTM Standards, part 23, Philadelphia, 1971, ASTM Designation D-2928–71.

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15. Vennard, J. K., Elementary Fluid Mechanics, John Wiley and Sons, Inc., New York, 1947.

METHOD 102. REFERENCE METHOD FOR DETERMINATION OF PARTICULATE AND GASEOUS MERCURY EMISSIONS FROM STATIONARY SOURCES

(HYDROGEN STREAMS)

1. Principle and applicability-1.1 Principle.-Particulate and gaseous mercury emissions are isokinetically sampled from the source and collected in acidic iodine monochloride solution. The mercury collected (in the mercuric form) is reduced to elemental mercury in basic solution by hydroxylamine sulfate. Mercury is aerated from the solution and analyzed using spectrophotometry.

1.2 Applicability. This method is applicable for the determination of particulate and gaseous mercury emissions when the carrier gas stream is principally hydrogen. The method is for use in ducts or stacks at stationary sources. Unless otherwise specified, this method is not intended to apply to gas streams other than those emitted directly to the atmosphere without further processing.

2. Apparatus-2.1 Sampling train.-A schematic of the sampling train used by EPA is shown in figure 102-1. Commercial models of this train are available, although complete construction details are described in APTD

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0581,1 and operating and maintenance procedures are described in APTD-0576. The components essential to this sampling train are the following:

2.1.1 Nozzle. Stainless steel or glass with sharp, tapered leading edge.

2.1.2 Probe. Sheathed Pyrex glass.

2.1.3 Pitot tube. Type S (figure 102-2), or equivalent, with a coefficient within 5 percent over the working range, attached to probe to monitor stack gas velocity.

2.1.4 Impingers. Four Greenburg-Smith impingers connected in series with glass balljoint fittings. The first, third, and fourth impingers may be modified by replacing the tip with one-half inch ID glass tube extending to one-half inch from the bottom of the flask.

2.1.5 Acid trap. Mine safety appliances air line filter, catalogue No. 81857, with acid absorbing cartridge and suitable connections, or equivalent.

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ACID TRAP

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Figure 102-1. Mercury sampling train

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2.1.6 Metering system. Vacuum gage, leakless pump, thermometers capable of measuring temperature to within 5°F, dry gas meter with 2 percent accuracy, and related equipment, described in APTD-0581, to maintain an isokinetic sampling rate and to determine sample volume.

2.1.7 Barometer. To measure atmospheric pressure to ± 0.1 in hg.

2.2 Measurement of stack conditions (stack pressure, temperature, moisture, and velocity)-2.2.1 Pitot tube. Type S, or equivalent, with a coefficient within 5 percent over the working range.

2.2.2 Differential pressure gage. Inclined manometer, or equivalent, to measure velocity head to within 10 percent of the minimum value. Micromanometers should be used if warranted.

2.2.3 Temperature gage. Any temperature-measuring device to measure stack temperature to within 1° F.

2.2.4 Pressure gage. Pitot tube and inclined manometer, or equivalent, to measure stack pressure to within 0.1 in hg.

2.2.5 Moisture determination. Drying tubes, condensers, or equivalent, to determine stack gas moisture content in hydrogen to within 1 percent.

2.3 Sample recovery-2.3.1 Leakless glass sample bottles. 500 ml and 200 ml with Teflon-lined tops.

2.3.2 Graduated cylinder. 250 ml. 2.3.3 Plastic jar. Approximately 300 ml. 2.4 Analysis-2.4.1 Spectrophotometer.

To measure absorbance at 253.7 nm. Perkin Elmer model 303, with a cylindrical gas cell (approximately 1.5 in o.d. x 7 in) with quartz glass windows, and hollow cathode source, or equivalent.

2.4.2 Gas sampling bubbler. Tudor Scientific Co. Smog Bubbler, catalogue No. TP1150, or equivalent.

2.4.3 Recorder. To match output of spectrophotometer.

reagents.-3.1.1

3. Reagents.-3.1 Stock Potassium iodide. Reagent grade.

3.1.2 Distilled water.

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3.1.3 Potassium Iodide solution, 25 percent.-Dissolve 250 g of potassium iodide (reagent 3.1.1) in distilled water and dilute to 1 to 1.

3.1.4 Hydrochloric acid. Concentrated. 3.1.5 Potassium iodate. Reagent grade. 3.1.6 Iodine monochloride (ICI) 1.0M. To 800 ml of 25 percent potassium iodide solution (reagent 3.1.3), add 800 ml of concentrated hydrochloric acid. Cool to room temperature. With vigorous stirring, slowly add 135 g of potassium iodate and continue stirring until all free iodine has dissolved to give a clear orange-red solution. Cool to room temperature and dilute to 1,800 ml with distilled water. The solution should be kept in amber bottles to prevent degradation.

3.1.7

grade.

3.1.8

3.1.9

Sodium hydroxide pellets. Reagent

Nitric acid. Concentrated. Hydroxylamine sulfate.

Reagent

grade. 3.1.10 Sodium chloride. Reagent grade. 3.1.11 Mercuric chloride. Reagent grade. 3.2 Sampling. 3.2.1 Absorbing solution, 0.1M ICI. Dilute 100 ml of the 1.0M IC1 stock solution (reagent 3.1.6) to 11 with distsilled water. The solution should be kept in glass bottles to prevent degradation. This reagent should be stable for at least 2 months; however, periodic checks should be performed to insure quality. Wash acid. 1:1 V/V nitric acid-water. Distilled, deionized water. 3.2.4 Silica gel. Indicating type, 6 to 16 mesh, dried at 350°F for 2 hours.

3.2.2 3.2.3

3.3. Analysis-3.3.1 Sodium hydroxide, 10N. Dissolve 400 g of sodium hydroxide pellets in distilled water and dilute to 1 1.

3.3.2 Reducing agent, 12 percent hydroxylamine sulfate, 12 percent sodium chloride. To 60 ml of distilled water, add 12 g of hydroxylamine sulfate and 12 g of sodium chloride. Dilute to 100 ml. This quantity is sufficient for 20 analyses and must be prepared daily.

3.3.3 Aeration gas. Zero grade air.

3.3.4 Hydrochloric acid, 0.3N. Dilute 25.5 ml of concentrated hydrochloric acid to 1 1 with distilled water.

3.4 Standard mercury solutions 3.4.1 Stock solution. Add 0.1354 g of mercuric chloride to 80 ml of 0.3N hydrochloric acid. After the mercuric chloride has dissolved, add 0.3N hydrochloric acid and adjust the volume to 100 ml. One ml of this solution is equivalent to 1 mg of free mercury.

3.4.2 Standard solutions. Prepare calibration solutions by serially diluting the stock solution (3.4.1) with 0.3N hydrochloric acid. Prepare solutions at concentrations in the linear working range for the instrument to be used. Solutions of 0.2 μg/ml, 0.4 μg/ml and 0.6 μg/ml have been found acceptable for most instruments. Store all solutions in glass-stoppered, glass bottles. These solutions should be stable for at least 2 months; however, periodic checks should be performed to insure quality.

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