N.J. Admin. Code § 7:27B-3.7

Current through Register Vol. 56, No. 19, October 7, 2024

Section 7:27B-3.7 - Procedures for the direct measurement of volatile organic compounds using a flame ionization detector (FID), a photoionization detector (PID) or a non-dispersive infrared analyzer (NDIR)

(a) The method in this section is applicable for the determination of the concentration and the mass emission rate of a known VOC or a mixture of known VOC in known proportions in systems with constant emissions and flow rates. For the same circumstances as described above, the procedures specified in 7:27B-3.8 or 3.9 may be used in place of this method. 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 flame ionization method is based upon ionization produced when the organic vapor in the sample 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 organic vapor.

2. The photoionization method is based upon ionization produced when an organic vapor in the sample is exposed to a high intensity ultraviolet source. The ions and electrons formed 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 organic vapor.

3. The non-dispersive infrared method is based upon absorption of infrared energy when a band of infrared energy containing the proper frequencies is alternately passed through an absorption cell containing the organic vapor and a reference cell. The difference in absorption between the reference cell and the absorption cell containing the organic vapor is proportional to the instantaneous concentration of the organic vapor.

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

1. The instrument is calibrated with standard gas mixtures to establish the instrument response to the VOC being analyzed. A representative sample of the source gas is drawn into the instrument under conditions which prevent any condensation of the source gas and which remove particulate matter. The response is recorded at specified intervals during the test period, and the true concentration of the VOC is calculated from previously determined response factors. The total gas flow rate, moisture content, and the average molecular weight of the gas are determined during the sampling period, and the mass emission rate of the VOC is calculated and reported as pounds per hour.

2. 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. Detector: a total hydrocarbon analysis instrument having a flame ionization, a photoionization or a non-dispersive infrared detector and a sampling system capable of preventing any condensation of the sample gas. The detector must be capable of meeting or exceeding the manufacturer's specifications by demonstration, preferably by the manufacturer, and the other specifications listed below:

i. Linearity: the instrument response to the VOC being measured shall not deviate from linearity by more than five percent of the full scale value of the range being used.

ii. Zero drift: less than three percent of full scale per test period or one hour, whichever is shorter.

iii. Span drift: less than three percent of full scale per test period or one hour whichever is shorter.

iv. Response time: equal to or less than 30 seconds for 95 percent full scale.

6. Recorder/Integrator:

7. Gas cylinder supplies as follows:

i. Laboratory standard calibration gases;

ii. Field standard: a known concentration of methane used to check instrument response in the field;

iii. Fuel gas;

iv. Combustion gas; and

v. Zero gas;

8. Velocity meter;

9. Condensor; and

10. Dilution system (if necessary): a system supplied by the instrument manufacturer or one similar to that specified in 7:27B-3.9(e)4, 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.

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

1. A presampling survey of the source operation shall be conducted to establish certain basic information including but not limited to: sampling location; stack temperature and pressure; stack gas moisture content; approximate particulate concentrations; 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 instructions;

ii. Adjust the analyzer to the zero reading by using zero gas; and

iii. Introduce three laboratory standard calibration gases separately recording the response for each. Plot the response versus the concentration. No response should deviate from the best fit line through the three points by more than five percent. If linearity cannot be obtained over the concentration range expected, the sample should be diluted to a concentration level where linearity can be obtained.

iv. Introduce a sample of the field standard and record the response.

3. The sampling and analysis shall be conducted as follows:

i. Assemble and connect any sampling probe, filter, and heating or dilution system to the instrument. All connections shall be tight and leak-free;

ii. Adjust the heating or dilution system to prevent any condensation of the sample gas;

iii. Analyze a sample of the field standard and adjust the instrument to the reading determined during calibration. If a dilution system must be used, record the response of the field standard with the dilution system in place and determine a new calibration curve at the same conditions used in the field;

iv. The probe should 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);

v. Activate the system and adjust as necessary to achieve the manufacturer's recommended operating conditions. Record the instrument response using a continuous recording device if available; if a continuous reading device is not available, take a reading at intervals of no less than one minute. Note any non-representative operations or occurrences during the testing and omit those corresponding analyzer readings from the calculations;

vi. 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);

vii. During the test period, determine the stack gas velocity, temperature, moisture content, average gas molecular weight, and volumetric flow rates 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 flow determining 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).)

viii. At the conclusion of each test run, note the time and introduce the field standard gas and determine and record its response. The net response must agree within five percent of the pretest response for the test to be valid.

(f) The calculations shall be performed as follows:

1. Establish the molecular weight of each VOC and calculate a weighted average molecular weight if more than one VOC is present.

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

3. Determine the response factor (RF) of the lab standard from the following equation.

RF=	C ppm (std)
______________________________
Response (Meter Reading)

4. Calculate the concentration of VOC as the standard as follows:

C (VOC as std.)=Instrument Response x RF

5. Calculate the emission rate in lbs/hr. expressed as the laboratory standard calibration gas.

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

Where:

C ppm (std)=the concentration in ppm of the standard mixture.

Avg. C ppm (VOC as std.)=average parts per million of VOC over the test period as laboratory standard calibration gas.

MW (std)=molecular weight of laboratory calibration standard (pounds per pound-mol).

SCFM=cubic feet per minute at 70 [degree]F and 1 atm emitted from the source operation.

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

RF=response factor for VOC.

NOTE: This formula is based upon the assumption that both the standards and the sample have been passed through the same sampling system and are diluted by the same amount.

(g) The test report shall include the following information submitted on the required reporting forms in Appendix B (any alternative reporting form shall be submitted to the Department for review prior to use 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 operation;

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

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

9. Operating conditions of the source operation; and

10. An explanation for any unusual procedures or results.

N.J. Admin. Code § 7:27B-3.7

Amended by R.1992 d.102, effective 3/2/1992 (operative March 28, 1992).
See: 23 New Jersey Register 1858(b), 24 New Jersey Register 792(a).
"VOS" changed to "VOC".