N.J. Admin. Code § 7:27B-3.9

Current through Register Vol. 56, No. 21, November 4, 2024

Section 7:27B-3.9 - Procedures for the sampling and remote analysis of known volatile organic compounds using a gas chromatograph (GC) with a flame ionization detector (FID) or other suitable detector

(a) The method in this section is applicable for the determination of the concentration and the mass emission rates of known VOC from a source where it is not practical to conduct a direct analysis at the source or in systems where the flow rates are not constant. For the same circumstances as described above, any other alternative test method shall be submitted to the Department for review pursuant to 7:27B-3.2(c), (d) and (e).

(b) This method is based upon the following principles:

1. The reduction of the moisture and VOC levels in the source gas by condensation or dilution;

2. Collecting the resulting dry sample gas in a Tedlar or equivalent bag;

3. Gas chromatography whereby each VOC is separated by passing an inert gas stream containing a known volume of the sample gas or standard gas through a column containing a stationary phase and/or a solid support; and

4. Ionization produced when each VOC in the sample gas as eluted from the gas chromatograph is combusted in a hydrogen flame. The ions and electrons formed in the flame enter an electrode gap, decrease the gap resistance, and thus permit a current flow in an external circuit. The resulting current is proportional to the instantaneous concentration of the VOC. Any alternative detector shall be submitted to the Department for review pursuant to 7:27B-3.2(c), (d) and (e).

(c) The following is a summary of this method:

1. A representative sample from the source is drawn at a constant rate through a heated sample line to a series of condensors in an ice bath where the moisture and condensable VOC are removed, or to a dilution system which reduces the concentration of the source gas by a known amount with hydrocarbon-free air. The dry sample gas is collected in a Tedlar or equivalent sampling bag which, along with any collected condensate, is transported to the GC-FID for analysis.

2. The GC-FID is calibrated with standard gas mixtures of each VOC being measured to establish the calibration curve and retention times. Representative portions of any condensate and the bag sample are injected separately into the calibrated GC-FID. The responses and retention times of the individual VOC are recorded on a strip chart recorder and the peak areas of each VOC are measured. The peaks are identified from the established retention times. The concentration of each VOC is determined by referring to the calibration curve. The total gas flow rate, moisture content, and the average molecular weight of the gas are determined during the sample period, and the mass emission rate of the VOC is calculated and reported as pounds per hour.

3. For the purposes of this procedure, three separate test runs will be conducted, each of which shall extend for one hour or a batch cycle whichever is longer. Any alternative test period shall be submitted to the Department for review pursuant to 7:27B-3.2(c), (d) and (e).

(d) The following is a list of equipment used in this method:

1. Probe;

2. Sample line;

3. Temperature sensor;

4. Pump;

5. Gas sampling valve;

6. Needle valve;

7. Condensation trap: three midget impingers (two with 10 ml of distilled water and one dry) in an ice bath;

8. Gas meter: a dry gas meter to measure the volume of the gas sample collected;

9. Sample bag: a Tedlar or equivalent bag with a volume at least 50 percent greater than the expected sample size and equipped with a hose connection and shut-off valve to collect and store the sample;

10. Gas chromatograph--flame ionization detector (GC-FID);

11. Recorder/Integrator;

12. Gas cylinder supplies, including the following:

i. Laboratory standard calibrations gases;

ii. Pure component standards;

iii. Fuel gas;

iv. Combustion gas; and

v. Carrier gas.

13. Velometer;

14. Condensor (water);

15. Condensor (VOC): a system as specified in (e)3 below for collecting condensible VOC and moisture from the source gas consisting of: a probe, three midget impingers (two containing ten ml. of distilled water and one dry, all three immersed in an ice bath), a pump, and a dry gas meter all connected in series;

16. Dilution system (if circumstances require): a system as specified in (e)4 below, capable of producing dilution ratios which will prevent any condensation of the sample gas and capable of bringing the sample concentration within the linear range of the detector;

17. Rotameters: flowmeters constructed of glass, stainless steel or Teflon of appropriate size used to measure the gas flow rate. The meters must be heated, if necessary, and calibrated with the gas to be measured. A calibration may be made with another gas and then corrected accordingly;

18. Charcoal tube: a drying tube filled with activated charcoal with glass wool plugs in both ends to absorb organic vapors from the vented sample gas and to prevent the release of VOC into the work area;

19. Dilution gas; and

20. Sparger module: a sparge-desorb module to strip VOC from the impinger condensate and trap the VOC on a suitable adsorbant.

(e) The procedure for this section shall be as follows:

1. A presampling survey of the source operation(s) must be conducted to establish certain basic information including but not limited to: sampling location, stack temperature and pressure, stack gas moisture content, approximate particulate concentration, composition of the gases, and the identification and approximate concentrations of the VOC to be analyzed. It may be necessary to take samples for analysis to acquire any information that is not readily available;

2. The instrument shall be calibrated as follows:

i. The instrument shall be operated according to the manufacturer's instruction;

ii. The operating parameters of the instrument such as column selections, temperatures, carrier gas flow rate, and chart speed must be established for the VOC to be measured, and verified in the laboratory prior to the actual sampling. The conditions selected should produce baseline separation of the individual VOC peaks, if possible, but in no case should the height of the valley between the peaks measured from the baseline to the lowest point in the valley be greater than 30 percent of the height of the shorter of the two peaks. More than one set of conditions may be necessary for complete resolution;

iii. The instrument operating conditions shall be recorded on the chart and maintained throughout the calibration and sample gas analyses. The operating conditions are sample loop temperature, column temperature, carrier gas flow rate, and chart speed. Attenuator settings shall be adjusted as required and recorded on the chart to indicate the time and amount of adjustment;

iv. Purge the sample loop with one of the calibration gas mixtures and record the concentration;

v. Activate the sampling valve to inject the sample and mark the injection point on the chart;

vi. Measure the distance on the chart from the injection point to the time at which the peak maximum occurs for the calibration mixture. This distance divided by the chart speed will provide the retention time for each compound; and

vii. Calculate the sample peak areas by multiplying the height times the width at half height and adjust each peak area by the attenuator setting as required. An integrator may be used to calculate peak areas.

viii. Repeat steps iv through vii for each calibration gas until two consecutive analyses agree within five percent. The corresponding peak areas for each VOC shall then be averaged.

ix. Plot the areas of each peak versus the concentrations on suitable graph paper. If any point should deviate from a straight line by more than five percent, the calibration shall be repeated. If a straight line is not obtained, less concentration standards or a smaller sample must be used to bring the response within the linear range of the detector.

x. Draw a straight line through the points to establish a calibration curve for each VOC. Calculate the unknown VOC concentrations from their peak areas by reading from appropriate calibration curve or by multiplying the peak area by the slope of the calibration curve. Extrapolation beyond the calibrated range is not acceptable.

xi. The instrument calibration shall be checked just prior to each test. The calibration gas shall be introduced through the sampling system in a manner similar to the introduction of the source gas.

3. Sampling shall be conducted as follows when using a condensor system:

i. Each bag shall be tested for contamination by filling with nitrogen or air and allowing it to stand for 24 hours. The gases shall be analyzed by gas chromatograph at high sensitivity. Any bag found to be contaminated shall be discarded.

ii. Each bag shall be checked for leaks by pressurizing it to two to four inches of water and allow to stand overnight. A deflated bag indicates a leak.

iii. Connect the probe to a condensor, sample bag, pump, and a dry gas meter as shown. See Appendix C. See Appendix D for the required reporting form. (Any alternative reporting form shall be submitted to the Department for review pursuant to N.J.A.C. 7:7B-3.2(c) and (e));

iv. Conduct a leak check according to the following procedure:

(1) Insert a clean, leak-free sample bag in the rigid container and prepare the container for a leak check. If the sampling container is truly rigid, the following leak-check shall be performed:

(A) Adjust the three-way valves to allow the evacuation of the rigid container;

(B) Plug the end of the probe and pull a vacuum of 15 inches mercury across the sampling train; and

(C) Monitor the flow meter and gas meter for flow movement. Any leak equal to or greater than four percent of the sampling rate is unacceptable;

(D) If an unacceptable leak exists, it shall be corrected and the leak check procedure repeated. If a leak occurred, the sample bag will have to be reevacuated prior to sampling. This is done by realigning the three-way valves so that a vacuum can be applied directly to the sample bag.

(2) If the sampling container cannot hold a vacuum of 15 inches mercury, then the following leak check procedures shall be used:

(A) Adjust the three-way valves to prevent any flow from entering the sample bag and with a water manometer in the line, pull a vacuum of 5-10 cm water (2-4 in. water) on the rigid container and then seal the container in such a way as to monitor the container pressure. Allow to stand for ten minutes. Any displacement in the water manometer indicates a leak. Refer to (1)(D), above if a leak occurs.

(B) After successfully leak checking the rigid container, adjust the three-way valves to by-pass the rigid container; and repeat steps (1)(B) and (1)(C), above.

v. Turn on the probe heating system and adjust to a temperature to prevent any condensation of the sample gas;

vi. The probe should be positioned at least two feet into the stack or at the centroid of the stack. The sample port location shall be in accordance with 7:27B-3.18, Reference 1. Record the initial meter volume;

vii. Purge the system by aligning the three-way valves on the rigid container so that a vacuum can be pulled directly on the impingers. The three-way valves shall be located close to the rigid container to avoid dilution air from entering the sample bag;

viii. Turn on the pump and adjust the flow so that a minimum of 20 liters of sample gas will be collected during the test period;

ix. Purge the system for five minutes, then realign the three-way valves on the rigid container so that the sample bag will be on the stream with the source gas. Continue to sample in this manner for the remainder of the test run;

x. Record the temperatures and pressures at five-minute intervals during the test period. See Appendix E for the required reporting form. (Any alternative reporting form shall be submitted to the Department for review pursuant to 7:27B-3.2(c) and (e).)

xi. Record the final meter volume at the conclusion of the test run. Remove the probe from the stack and perform a leak check as previously described. The test shall be voided if the leak rate is equal to or greater than four percent of the sampling rate as determined on the first post test leak check attempt;

xii. Rinse the probe, all connecting lines through the impingers and the impingers with an appropriate solvent. The rinse solution and impinger collect shall be placed in an opaque leak-proof container for later analysis. The container should be filled to minimize loss of VOC in the headspace;

xiii. The sample bag must be protected from heat and sunlight to prevent reactions between sample components and should be analyzed within 24 hours unless it can be shown that significant sample degradation does not occur;

xiv. For the purposes of this procedure, three separate and valid test runs will be conducted, each of which shall extend for one hour or a batch cycle whichever is longer. Any alternative test period shall be submitted to the Department for review pursuant to 7:27B-3.2(c), (d) and (e);

xv. During the test period, determine the stack gas velocity, temperature, moisture content, average gas molecular weight and volumetric flow rate in accordance with the methods prescribed in N.J.A.C. 7:27B-1 AIR TEST METHOD 1 (7:27B-3.18, Reference 1), or other alternative method, which shall be submitted to the Department for review pursuant to 7:27B-3.2(c), (d) and (e). See Appendix A for the required reporting form. (Any alternative reporting form shall be submitted to the Department for review pursuant to 7:27B-3.2(c) and (e).)

xvi. At the conclusion of each test run introduce the calibration gas in a manner similar to the introduction of the source gas and determine the response. The net response must agree to within +/- five percent of the pretest response for the test to be valid.

4. Sampling shall be conducted as follows when using a dilution system:

i. Each bag shall be tested for contamination by filling with nitrogen or air and allowing it to stand for 24 hours. The gas shall be analyzed by gas chromotagraph at high sensitivity. Any bag found to be contaminated shall be discarded.

ii. Each bag shall be checked for leaks by pressurizing it to two to four inches of water and allow to stand overnight. A deflated bag indicates a leak.

iii. Connect the probe to a dilution system, sample bag, pump, and a dry gas meter in series as shown. See Appendix C. See Appendix D for the required reporting form. (Any alternative reporting form shall be submitted to the Department for review pursuant to 7:27B-3.2(c) and (e).)

iv. Conduct a leak check according to the procedure outlined in (e)3ii above;

v. Turn on the probe heating system and adjust to a temperature which will prevent condensation;

vi. The probe shall be positioned at least two feet into the stack or at the centroid of the stack. The sample port location should be in accordance with N.J.A.C. 7:27B-1, AIR TEST METHOD 1 (7:27B-3.18, Reference 1);

vii. Purge the system by aligning the three-way valves on the rigid container so a vacuum can be pulled directly on the dilution system. The three-way valves shall be located close to the rigid container to avoid dilution air from entering the sample bag;

viii. Turn on the pump and adjust the flow to give the desired dilution rate and to ensure that a minimum of 20 liters of sample gas will be collected during the test period;

ix. Before sampling, verify that the system is working properly by introducing a calibration gas into the system and collect an audit sample maintaining the same operation conditions to be used during sampling. Transport this sample to the GC for immediate analysis, if possible; otherwise repeat the audit at the end of the tests and transport the audit samples to the laboratory along with the test samples. The audit results should be within five percent of the calibration gas concentration; if not, correct the problem and repeat the audit. In cases where immediate analysis is not possible, the audit results may be used to determine a correction factor;

x. Purge the system for five minutes. Then realign the three-way valves on the rigid container so the sample bag will be on stream with the source gas. Continue to sample maintaining the same dilution rate used for the audit test for the remainder of the test run;

xi. Record the temperatures and pressures at five-minute intervals during the test period. See Appendix E for required reporting form. (Any alternative reporting form shall be submitted to the Department for review pursuant to 7:27B-3.2(c) and (e).)

xii. Record the final meter volume at the conclusion of the test run. Remove the probe from the stack and perform a leak check as previously described. The test shall be voided if the leak rate is equal or greater than four percent of the sampling rate as determined on the first post test leak check attempt; and

xiii. Remove the sample bag from the rigid container. Visually inspect the sample bag. If any condensation is observed, the test run shall be voided and a new run must be conducted using a greater dilution ratio;

xiv. The sample bag must be protected from heat and sunlight to prevent reactions between sample components and should be analyzed within 24 hours unless it can be shown that significant sample degradation does not occur;

xv. For the purpose of this procedure, three separate and valid test runs shall be conducted, each of which shall extend for one hour or a batch cycle, whichever is longer. Any alternative test period shall be submitted to the Department for review pursuant to 7:27B-3.2(c), (d) and (e);

xvi. During the test period, determine the stock gas velocity, temperature, moisture content, average gas molecular weight, and volumetric flow rate in accordance with the methods prescribed in N.J.A.C. 7:27B-1 AIR TEST METHOD 1 (7:27B-3.18, Reference 1), or other appropriate flow determining method which shall be submitted to the Department for review pursuant to 7:27B-3.2(c), (d) and (e). See the required reporting form at Appendix A. (Any alternative reporting form shall be submitted to the Department for review pursuant to 7:27B-3.2(c) and (e).)

5. The bag sample shall be analyzed as follows:

i. Turn on the GC and adjust the sample valve and those conditions which will prevent any condensation of the sample gas;

ii. After thoroughly purging the gas sampling loop with source gas, analyze an aliquot of the bag sample maintaining the same instrument operating conditions used during the calibration procedures; and

iii. Analyze each sample until two consecutive analyses agree within five percent. Average the corresponding peak areas for each compound. Calculate the concentrations of the components by referring to the calibration curves.

6. The condensation trap shall be analyzed as follows:

i. Connect the sparge and trap module to the GC injection system and set the valve, desorb temperature, and the inert gas flow rate as per manufacturer's specifications;

ii. Mix the condensate solution to obtain a representative sample and fill the sparger to the recommended volume;

iii. Sparge the sample into an appropriate trap for a minimum of 10 minutes with an inert gas. Thermally desorb the VOC from the trap onto the GC column and analyze the VOC employing the same instrument conditions used during the calibration procedures. Measure the area under each VOC peak. Save the sparged solution;

iv. Analyze each sample until two consecutive analyses agree within five percent. Average the corresponding peak areas for each component and calculate the concentrations of the components by referring to the calibration curves;

v. Combine the sparged solutions and analyze by either extracting with a solvent or by re-sparging an aliquot as a check on the sparge efficiency; and

vi. Inject an appropriate aliquot of the rinse solution into the GC, employing the same instrument conditions used during the calibration procedures. Measure the area under each peak, eliminating the solvent area.

(f) The calculations shall be performed as follows:

1. Establish the molecular weight of each VOC from the literature.

2. Calculate the total gas flow rate from the source operations in SCFM (70 [degree] F and 1 atm) including the VOC and any moisture present.

i. If impingers are used calculate the SCFM on a dry basis.

ii. If a dilution system is used with no impingers calculate the SCFM on a wet basis.

3. All flow meter readings must be corrected for temperature, pressure and specific gas density if necessary.

4. Bag Sample: Determine the concentration (C) of each VOC in ppm (Cppm VOC) by using the calibration curves developed in (e)2x above and the area of each VOC. If the sample is collected using a dilution system, the concentrations shall be corrected by the dilution factor (Df) as determined by the following formula:

Df=	ml/min dilution gas + ml/min source gas
.........................................
ml/min source gas

5. Condensate and rinse: Convert the calibration curves used in (e)2x above from ppm vs. area to microgram (ugm) vs. area. Determine the concentration (C) of each VOC in the condensate and rinse in ppm (Cppm VOC) in the vapor phase from the VOC peak areas and the calibration curves using the following formula:

Cppm VOC=	(Area) (slope) x Vc x 24.1
............................
Vj x MW (VOC) x Vg

Where:

Area=area of VOC peak (area units).

Slope=slope of calibration curve (ugm/area unit).

Vc=Condensate Volume (milliliters).

Vj=injection volume (milliliters).

Vg=volume of gas sampled (liters).

MV VOC=molecular weight of VOC (gram per gram mol).

24.1=molar volume at standard conditions in liters per gram mol.

6. Determine the total concentration (C) of each VOC in the source gas in ppm (C ppm) by summing the results of each VOC from 4 and 5 above;

7. Calculate the emission rate in lbs/hr of each VOC as follows:

lbs VOC	=	C ppm(VOC) x SCFM x MW (VOC) x 60 min/hr
....... .............................................
hr	387 x 10<6>

Where:

C ppm (VOC)=sum of bag sample and condensate concentrations in part per million of each VOC.

MW (VOC)=molecular weight of VOC (pounds per pound-mol).

SCFM=cubic feet minute at 70 [degree]F and 1 atm emitted from the source operation (dry if impingers used; wet if no impingers used).

387=molar volume at standard conditions in cubic feet per pound-mol.

8. Calculate the total emission rate of VOC in lb/hr by totaling the emission rates of each individual VOC as calculated in 6 above.

(g) The test report shall include the following information submitted on the required reporting forms listed in Appendices D and E (any alternative reporting forms shall be submitted to the Department for review pursuant to 7:27B-3.2(c) and (e)) :

1. A dimensioned sketch of the sampling location;

2. All data used to determine the volume flow rate;

3. The composition of the gas and its average molecular weight;

4. A sketch and/or description of the sampling system used;

5. The identity, concentration and means of verification for each standard used;

6. A description of the analysis instrument and the conditions of operations;

7. Copies of the chromatograms for each standard and each test run identified as to time taken and pertinent instrument and dilution conditions;

8. Sufficient details of the calculations to allow the results to be reproduced independently;

9. The emission rate measured in lbs/hr of each VOC for each test;

10. Operating conditions of the source operation; and

11. An explanation for any unusual procedures or results.

N.J. Admin. Code § 7:27B-3.9