Enmienda la Regla 102 y la Parte VII del Reglamento para el Control de la Contaminación Atmosférica

3.1.3 Performance Evaluation Requirements. a. A response factor must be determined for each compound that is to be measured, either by testing or from reference sources. The response factor tests are required before placing the analyzer into service, but do not have to be repeated at subsequent intervals. b. The calibration precision test must be completed prior to placing the analyzer into service, and at subsequent 3-month intervals or at the next use whichever is later. C. The response time test is required before placing the instrument into service. If a modification to the sample pumping system or flow configuration is made that would change the response time, a new test is required before further use. 3.2 Calibration Gases. The monitoring instrument is calibrated in terms of parts per million by volume (ppm) of the reference compound specified in the applicable regulation. The calibration gases required for monitoring and instrument performance evaluation are a zero gas (air, less than 10 ppm VOC) and a calibration gas in air mixture approximately equal to the leak definition specified in the regulation. If cylinder calibration gas mixtures are used, they must be analyzed and certified by the manufacturer to be within + or - 2 percent accuracy, and a shelf life must be specified. Cylinder standards must be either reanalyzed or replaced at the end of the specified shelf life. Alternatively, calibration gases may be prepared by the user according to any accepted gaseous preparation procedure that will yield a mixture accurate to within + or - 2 percent. Prepared standards must be replaced each day of use unless it can be demonstrated that degradation does not occur during storage. Calibrations may be performed using a compound other than the reference compound if a conversion factor is determined for that alternative compound so that the resulting meter readings during source surveys can be converted to reference compound results. 4. PROCEDURES 4.1 Pretest Preparations. Perform the instrument evaluation procedure given in Section 4.4 if the evaluation requirement of Section 3.1.3 have not been met. 4.2 Calibration Procedures. Assemble and start up the VOC analyzer according to the manufacturer's instructions. After the appropriate warmup period and zero internal calibration procedure, introduce the calibration gas into the instrument sample probe. Adjust the instrument meter readout to correspond to the calibration gas value. (Note: If the meter readout cannot be adjusted to the proper value, a malfunction of the analyzer is indicated and corrective actions are necessary before use.) 4.3 Individual Source Surveys. 4.3.1 Type I - Leak Definition Based on Concentration. Place the probe inlet at the surface of the component interface where leakage could occur. Move the probe along the interface periphery while observing the instrument readout. If an increased meter reading is observed, slowly sample the interface where leakage is indicated until the maximum meter reading is obtained. Leave the probe inlet at this maximum reading location for approximately two times the instrument response time. If the maximum observed meter reading is greater than the leak definition in the applicable regulation, record and report the results as specified in the regulation reporting requirements. Examples of the application of this general technique to specific equipment types are: a. Valves - Leaks usually occur at the seal between the stem and the housing. Place the probe at the interface where the stem exits the packing and sample the stem circumference and the flange periphery. Survey valves of multipart assemblies where a leak could occur. b. Flanges and Other Connections - Place the probe at the outer edge of the flange-gasket interface and sample the circumference of the flange. C. Pump or Compressor Seals - If applicable, determine the type of shaft seal. Perform a survey of the local area ambient VOC concentration and determine if detectable emissions exist as described above. d. Pressure Relief Devices - For those devices equipped with an enclosed extension, or horn, place the probe inlet at approximately the center of the exhaust area to the atmosphere. e. Process Drains - For open drains, place the probe inlet as near as possible to the center of the area open to the atmosphere. For covered drains, locate probe at the surface of the cover and traverse the periphery. f. Open-ended Lines or Valves - Place the probe inlet at approximately the center of the opening of the atmosphere. g. Seal System Degassing Vents, Accumulator Vessel Vents, Pressure Relief Devices - If applicable, observe whether the applicable ducting or piping exists. Also, determine if any sources exist in the ducting or piping where emissions could occur before the control device. If the required ducting or piping exists and there are no sources where the emissions could be vented to the atmosphere before the control device, then it is presumed that no detectable emissions are present. If there are sources in the ducting or piping where emissions could be vented or sources where leaks could occur, the sampling surveys described in this section shall be used to determine if detectable emissions exist. h. Access door seals - Place the probe inlet at the surface of the door seal interface and traverse the periphery. 4.3.2 Type II - "No Detectable Emission". Determine the ambient concentration around the source by moving the probe randomly upwind and downwind around one to two meters from the source. In case of interferences, this determination may be made closer to the source down to no closer than 25 centimeters. Then move the probe to the surface of the source and measure as in 4.3.1. The difference in these concentrations determines whether there are no detectable emissions. When the regulation also requires that no detectable emissions exist, visual observations and sampling surveys are required. Examples of this technique are: (a) Pump or Compressor Seals - Survey the local area ambient VOC concentration and determine if detectable emissions exist. (b) Seal System Degassing Vents, Accumulator Vessel Vents, Pressure Relief Devices - Determine if any VOC sources exist upstream of the device. If such ducting exists and emissions cannot be vented to the atmosphere upstream of the control device, then it is presumed that no detectable emissions are present. If venting is possible sample to determine if detectable emissions are present. 4.3.3 Alternative Screening Procedure. 4.3.3.1 A screening procedure based on the formation of bubbles in a soap solution that is sprayed on a potential leak source may be used for those sources that do not have continuously moving parts, that do not have surface temperatures greater than the boiling point or less than the freezing point of the soap solution, that do not have open areas to the atmosphere that the soap solution cannot bridge, or that do not exhibit evidence of liquid leakage. Sources that have these conditions present must be surveyed using the instrument technique of Section 4.3.1 or 4.3.2. 4.3.3.2 Spray a soap solution over all potential leak sources. The soap Solution may be a commercially available leak detection solution or may be prepared using concentrated detergent and water. A pressure sprayer or squeeze bottle may be used to dispense the solution. Observe the potential leak sites to determine if any bubbles are formed. If no bubbles are observed, the source is presumed to have no detectable emissions or leaks as applicable. If any bubbles are observed, the instrument techniques of Section 4.3.1 or 4.3.2 shall be used to determine if a leak exists, or if the source has detectable emissions, as applicable. 4.4 Instrument Evaluation Procedures. At the beginning of the instrument performance evaluation test, assemble and start up the instrument according to the manufacturer's instructions for recommended warmup period and preliminary adjustments. 4.4.1 Response Factor. 4.4.1.1 Calibrate the instrument with the reference compound as specified in the applicable regulation. For each organic species that is to be measured during individual source surveys, obtain or prepare a known standard in air at a concentration of approximately 80 percent of the applicable leak definition unless limited by volatility or explosivity. In these cases, prepare a standard at 90 percent of the standard saturation concentration, or 70 percent of the lower explosive limit, respectively. Introduce this mixture to the analyzer and record the observed meter reading. Introduce zero air until a stable reading is obtained. Make a total of three measurements by alternating between the known mixture and zero air. Calculate the response factor for each repetition and the average response factor. 4.4.1.2 Alternatively, if response factors have been published for the compounds of interest for the instrument or detector type, the response factor determination is not required, and existing results may be referenced. Examples of published response factors for flame ionization and catalytic oxidation detectors are included in the Bibliography. 4.4.2 Calibration Precision. Make a total of three measurements by alternately using zero gas and the specified calibration gas. Record the meter readings. Calculate the average algebraic difference between the meter readings and the known value. Divide this average difference by the known calibration value and multiply by 100. to express the resulting calibration precision as a percentage. 4.4.3 Response Time. Introduce zero gas into the instrument sample probe. When the meter reading has stabilized, switch quickly to the specified calibration gas. Measure the time from switching to when 90 percent of the final stable reading is attained. Perform this test sequence three times and record the results. Calculate the average response time. 5. BIBLIOGRAPHY 1. Dubose, D.A., and G.E. Harris. Response Factors of VOC Analyzers at a Meter Reading of 10,000 ppmv for Selected Organic Compounds. U.S. Environmental Protection Agency, Research Triangle Park, NC, Publication No. EPA 600/2-81051. September 1981. 2. Brown, G.E., et al. Response Factors of VOC Analyzers Calibrated with Methane for Selected Organic Compounds. U.S. Environmental- Protection Agency, Research Triangle Park, NC. Publication No. EPA 600/2-81-022. May 1981. 3. DuBose, D.A. et al. Response of Portable VOC Analyzers to Chemical Mixtures. U.S. Environmental Protection Agency, Research Triangle Park, NC. Publication No. EPA 600/2-81-110. September 1981, APÉNDICE A MÉTODO 25 DEL 40 CRF PARTE 60 EMISSION MEASUREMENT TECHNICAL INFORMATION CENTER NSPS TEST METHOD (EMTIC M-25, 6/18/93) Method 25 - Determination of Total Gaseous Nonmethane Organic Emissions as Carbon 1. APPLICABILITY AND PRINCIPLE 1.1 Applicability. 1.1.1 This method applies to the measurement of volatile organic compounds (VOC) as total gaseous nonmethane organics (TGNMO) as carbon in source emissions. Organic particulate matter will interfere with the analysis and, therefore, a particulate filter is required. 1.1.2 When carbon dioxide (CO₂) and water vapor are present together in the stack, they can produce a positive bias in the sample. The magnitude of the bias depends on the concentrations of CO₂ and water vapor. As a guideline, multiply the CO₂ concentration, expressed as volume percent, times the water vapor concentration. If this product does not exceed 100, the bias can be considered insignificant. For example, the bias is not significant for a source having 10 percent CO₂ and 10 percent water vapor, but it might be significant for a source having 10 percent CO₂ and 20 percent water vapor. 1.1.3 This method is not the only method that applies to the measurement of TGNMO. Costs, logistics, and other practicalities of source testing may make other test methods more desirable for measuring VOC contents of certain effluent streams. Proper judgment is required in determining the most applicable VOC test method. For example, depending upon the molecular weight of the organics in the effluent stream, a totally automated semicontinuous nonmethane organics (NMO) analyzer interfaced directly to the source may yield accurate results. This approach has the advantage of providing emission data semicontinuously over an extended time period. 1.1.4 Direct measurement of an effluent with a flame ionization detector (FID) analyzer may be appropriate with prior characterization of the gas stream and knowledge that the detector responds predictably to the organic compounds in the stream. If present, methane (CH4) will, of course, also be measured. The FID can be applied to the determination of the mass concentration of the total molecular structure of the organic emissions under any of the following limited conditions: (1) where only one compound is known to exist; (2) when the organic compounds consist of only hydrogen and carbon; (3) where the relative percentages of the compounds are known or can be determined, and the FID responses to the compounds are known; (4) where a consistent mixture of the compounds exists before and after emission control and only the relative concentrations are to be assessed; or (5) where the FID can be calibrated against mass standards of the compounds emitted (solvent emissions, for example). 1.1.5 Another example of the use of a direct FID is as a screening method. If there is enough information available to provide a rough estimate of the analyzer accuracy, the FID analyzer can be used to determine the VOC content of an uncharacterized gas stream. With a sufficient buffer to account for possible inaccuracies, the direct FID can be a useful tool to obtain the desired results without costly exact determination. Prepared by Emission Measurement Branch EMTIC TM-25 Technical Support Division, OAQPS, EPA June 18, 1993 1.1.6 In situations where a qualitative/quantitative analysis of an effluent stream is desired or required, a gas chromatographic FID system may apply. However, for sources emitting numerous organics, the time and expense of this approach will be formidable. 1.2 Principle. An emission sample is withdrawn from the stack at a constant rate through a heated filter and a chilled condensate trap by means of an evacuated sample tank. After sampling is completed, the TGNMO are determined by independently analyzing the condensate trap and sample tank fractions and combining the analytical results. The organic content of the condensate trap fraction is determined by oxidizing the NMO to CO₂ and quantitatively collecting in the effluent in an evacuated vessel; then a portion of the CO₂ is reduced to CH4 and measured by an FID. The organic content of the sample tank fraction is measured by injecting a portion of the sample into a gas chromatographic column to separate the NMO from carbon monoxide (CO), CO2, and CH4; the NMO are oxidized to CO2, reduced to CH4, and measured by an FID. In this manner, the variable response of the FID associated with different types of organics is eliminated. 2. APPARATUS 2.1 Sampling. The sampling system consists of a heated probe, heated filter, condensate trap, flow control system, and sample tank (Figure 25-1). The TGNMO sampling equipment can be constructed from commercially available components and components fabricated in a machine shop. The following equipment is required: 2.1.1 Heated Probe. 6.4-mm (1/4-in.) OD stainless steel tubing with a heating system capable of maintaining a gas temperature at the exit end of at least 129'C (265'F). The probe shall be equipped with a thermocouple at the exit end to monitor the gas temperature. 2.1.1.1 A suitable probe is shown in Figure 25-1. The nozzle is an elbow fitting attached to the front end of the probe while the thermocouple is inserted in the side arm of a tee fitting attached to the rear of the probe. The probe is wrapped with a suitable length of high temperature heating tape, and then covered with two layers of glass cloth insulation and one layer of aluminum foil. 2.1.1.2 Note: If it is not possible to use a heating system for safety reasons, an unheated system with an in-stack filter is a suitable alternative. 2.1.2 Filter Holder. 25-mm (15/16-in.) ID Gelman filter holder with 303 stainless steel body and 316 stainless steel support screen with the Viton O-ring replaced by a Teflon O-ring. (Note: Mention of trade names or specific products does not constitute endorsement by the Environmental Protection Agency.) 2.1.3 Filter Heating System. A metal box consisting of an inner and an outer shell separated by insulating material with a heating element in the inner shell capable of maintaining a gas temperature at the filter of 121 ± 3'C (250 ± 5'F). 2.1.3.1 A suitable heating box is shown in Figure 25-2. The outer shell is a metal box that measures 102 mm X 280 mm X 292 mm (4 in. X 11 in. X 11 1/2 in.), while the inner shell is a metal box measuring 76 mm X 229 mm X 241 mm (3 in. X 9 in. X 9 1/2 in.). The inner box is supported by 13-mm (1/2-in.) phenolic rods. The void space between the boxes is filled with fiberfrax insulation which is sealed in place by means of a silicon rubber bead around the upper sides of the box. A removable lid made in a similar manner, with a 25-mm (1-in.) gap between the parts is used to cover the heating chamber. 2.1.3.2 The inner box is heated with a 250-watt cartridge heater, shielded by a stainless steel shroud. The heater is regulated by a thermostatic temperature controller which is set to maintain a temperature of 121'C as measured by a thermocouple in the gas line just before the filter. An additional thermocouple is used to monitor the temperature of the gas behind the filter. 2.1.3.3 Note: If it is not possible to use a heating system for safety reasons, an unheated system with an in-stack filter is a suitable alternative. 2.1.4 Condensate Trap. 9.5-mm (3/8-in.) OD 316 stainless steel tubing bent into a U-shape. Exact dimensions are shown in Figure 25-3. The tubing shall be packed with coarse quartz wool, to a density of approximately 0.11 g/cc before bending. While the condensate trap is packed with dry ice in the Dewar, an ice bridge may form between the arms of the condensate trap making it difficult to remove the condensate trap. This problem can be prevented by attaching a steel plate between the arms of the condensate trap in the same plane as the arms to completely fill the intervening space. 2.1.5 Valve. Stainless steel control valve for starting and stopping sample flow. 2.1.6 Metering Valve. Stainless steel valve for regulating the sample flow rate through the sample train. 2.1.7 Rotameter. Glass tube with stainless steel fittings, capable of measuring sample flow in the range of 60 to 100 cc/min. 2.1.8 Sample Tank. Stainless steel or aluminum tank with a minimum volume of 4 liters. 2.1.9 Mercury Manometer. U-tube manometer or absolute pressure gauge capable of measuring pressure to within 1 mm Hg in the range of 0 to 900 mm. 2.1.10 Vacuum Pump. Capable of evacuating to an absolute pressure of 10 mm Hg. 2.2 Condensate Recovery Apparatus. The system for the recovery of the organics captured in the condensate trap consists of a heat source, oxidation catalyst, nondispersive infrared (NDIR) analyzer and an intermediate collection vessel (ICV). Figure 25-4 is a schematic of a typical system. The system shall be capable of proper oxidation and recovery, as specified in Section 5.1. The following major components are required: 2.2.1. Heat Source. Sufficient to heat the condensate trap (including probe) to a temperature of 200'C. A system using both a heat gun and an electric tube furnace is recommended. 2.2.2 Heat Tape. Sufficient to heat the connecting tubing between the water trap and the oxidation catalyst to 100'C. 2.2.3 Oxidation Catalyst. A suitable length of 9.5 mm (3/8-in.) OD Inconel 600 tubing packed with 15 cm (6 in.) of 3.2 mm (1/8 in.) diameter 19 percent chromia on alumina pellets. The catalyst material is packed in the center of the catalyst tube with quartz wool packed on either end to hold it in place. The catalyst tube shall be mounted vertically in a 650'C tube furnace. 2.2.4 Water Trap. Leak proof, capable of removing moisture from the gas stream. 2.2.5 Syringe Port. A 6.4-mm (1/4-in.) OD stainless steel tee fitting with a rubber septum placed in the side arm. 2.2.6 NDIR Detector. Capable of indicating CO₂ concentration in the range of zero to 5 percent, to monitor the progress of combustion of the organic compounds from the condensate trap. 2.2.7 Flow-Control Valve. Stainless steel, to maintain the trap conditioning system near atmospheric pressure. 2.2.8 Intermediate Collection Vessel. Stainless steel or aluminum, equipped with a female quick connect. Tanks with nominal volumes of at least 6 liters are recommended. 2.2.9 Mercury Manometer or Absolute Pressure Gauge. Capable of measuring pressure to within 1 mm Hg in the range of 0 to 900 mm. 2.2.10 Syringe. 10-ml gas-tight glass syringe equipped with an appropriate needle. 2.3 NMO Analyzer. The NMO analyzer is a gas chromatograph (GC) with backflush capability for NMO analysis and is equipped with an oxidation catalyst, reduction catalyst, and FID. Figures 25-5 and 25-6 are schematics of a typical NMO analyzer. This semicontinuous GC/FID analyzer shall be capable of: (1) separating CO, CO2, and CH4 from NMO, (2) reducing the CO₂ to CH4 and quantifying as CH4, and (3) oxidizing the NMO to CO2, reducing the CO₂ to CH4 and quantifying as CH4, according to Section 5.2. The analyzer consists of the following major components: 2.3.1 Oxidation Catalyst. A suitable length of 9.5-mm (3/8-in.) OD Inconel 600 tubing packed with 5.1 cm (2 in.) of 19 percent chromia on 3.2-mm (1/8-in.) alumina pellets. The catalyst material is packed in the center of the tube supported on either side by quartz wool. The catalyst tube must be mounted vertically in a 650 C furnace. 2.3.2 Reduction Catalyst. A 7.6-cm (3-in.) length of 6.4-mm (1/4-in.) OD Inconel tubing fully packed with 100-mesh pure nickel powder. The catalyst tube must be mounted vertically in a 400'C furnace. 2.3.3 Separation Column (s). A 30-cm (1-ft) length of 3.2-mm (1/8-in.) OD stainless steel tubing packed with 60/80 mesh Unibeads 1S followed by a 61-cm (2- ft) length of 3.2-mm (1/8-in.) OD stainless steel tubing packed with 60/80 mesh Carbosieve G. The Carbosieve and Unibeads columns must be baked separately at 200'C with carrier gas flowing through them for 24 hours before initial use. 2.3.4 Sample Injection System. A 10-port GC sample injection valve fitted with a sample loop properly sized to interface with the NMO analyzer (1-cc loop recommended). 2.3.5 FID. An FID meeting the following specifications is required: 2.3.5.1 Linearity. A linear response (±5 percent) over the operating range as demonstrated by the procedures established in Section 5.2.3. 2.3.5.2 Range. A full scale range of 10 to 50,000 ppm CH4. Signal attenuators shall be available to produce a minimum signal response of 10 percent of full scale. 2.3.6 Data Recording System. Analog strip chart recorder or digital integration system compatible with the FID for permanently recording the analytical results. 2.4 Other Analysis Apparatus. 2.4.1 Barometer. Mercury, aneroid, or other barometer capable of measuring atmospheric pressure to within 1 mm Hg. 2.4.2 Thermometer. Capable of measuring the laboratory temperature within 1'C. 2.4.3 Vacuum Pump. Capable of evacuating to an absolute pressure of 10 mm Hg. 2.4.4 Syringes. 10-µl and 50-µl liquid injection syringes. 2.4.5 Liquid Sample Injection Unit. 316 SS U-tube fitted with an injection septum, see Figure 25-7. 3. REAGENTS 3.1 Sampling. The following are required for sampling: 3.1.1 Crushed dry ice. 3.1.2 Coarse quartz wool. 8 to 15 µm. 3.2 NMO Analysis. The following gases are needed: 3.2.1 Carrier Gases. Zero grade helium (He) and oxygen (O₂) containing less than 1 ppm CO₂ and less than 0.1 ppm C as hydrocarbon. 3.2.2 Fuel Gas. Zero grade hydrogen (H₂), 99.999 percent pure. 3.2.3 Combustion Gas. Zero grade air or O₂ as required by the detector. 3.3 Condensate Analysis. The following gases are needed: 3.3.1 Carrier Gas. Zero grade air, containing less than 1 ppm C. 3.3.2 Auxiliary O₂. Zero grade O₂ containing less than 1 ppm C. 3.3.3 Hexane. ACS grade, for liquid injection. 3.3.4 Decane. ACS grade, for liquid injection. 3.4 Calibration. For all calibration gases, the manufacturer must recommend a maximum shelf life for each cylinder (i.e., the length of time the gas concentration is not expected to change more than ±5 percent from its certified value). The date of gas cylinder preparation, certified organic concentration, and recommended maximum shelf life must be affixed to each cylinder before shipment from the gas manufacturer to the buyer. The following calibration gases are required: 3.4.1 Oxidation Catalyst Efficiency Check Calibration Gas. Gas mixture standard with nominal concentration of 1 percent methane in air. 3.4.2 FID Linearity and NMO Calibration Gases. Three gas mixture standards with nominal propane concentrations of 20 ppm, 200 ppm, and 3000 ppm, in air. 3.4.3 CO2 Calibration Gases. Three gas mixture standards with nominal CO₂ concentrations of 50 ppm, 500 ppm, and 1 percent, in air. Note: Total NMO less than 1 ppm required for 1 percent mixture. 3.4.4 NMO Analyzer System Check Calibration Gases. Four calibration gases are needed as follows: 3.4.4.1 Propane Mixture. Gas mixture standard containing (nominal) 50 ppm CO, 50 ppm CH4, 2 percent CO2, and 20 ppm C3H₈, prepared in air. 3.4.4.2 Hexane. Gas mixture standard containing (nominal) 50 ppm hexane in air. 3.4.4.3 Toluene. Gas mixture standard containing (nominal) 20 ppm toluene in air. 3.4.4.4 Methanol. Gas mixture standard containing (nominal) 100 ppm methanol in air. 4. PROCEDURE 4.1 Sampling. 4.1.1 Sample Tank Evacuation and Leak Check. Evacuate the sample tank to 10 mm Hg absolute pressure or less. Then close the sample tank valve, and allow the tank to sit for 30 minutes. The tank is acceptable if a change in tank vacuum of less than 2 mm Hg is noted. The evacuation and leak check may be conducted either in the laboratory or the field. 4.1.2 Sample Train Assembly. Just before assembly, measure the tank vacuum using a mercury U-tube manometer. Record this vacuum, the ambient temperature, and the barometric pressure at this time. Close the sample tank valve and assemble the sampling system as shown in Figure 25-1. Immerse the condensate trap body in dry ice. The point where the inlet tube joins the trap body should be 2.5 to 5 cm above the top of the dry ice. 4.1.3 Pretest Leak Check. A pretest leak check is required. Calculate or measure the approximate volume of the sampling train from the probe tip to the sample tank valve. After assembling the sampling train, plug the probe tip, and make certain that the sample tank valve is closed. Turn on the vacuum pump, and evacuate the sampling system from the probe tip to the sample tank valve to an absolute pressure of 10 mm Hg or less. Close the purge valve, turn off the pump, wait a minimum period of 10 minutes, and recheck the indicated vacuum. Calculate the maximum allowable pressure change based on a leak rate of 1 percent of the sampling rate using Equation 25-1, Section 6.2. If the measured pressure change exceeds the calculated limit, correct the problem and repeat the leak check before beginning sampling. 4.1.4 Sample Train Operation. 4.1.4.1 Unplug the probe tip, and place the probe into the stack such that the probe is perpendicular to the duct or stack axis; locate the probe tip at a single preselected point of average velocity facing away from the direction of gas flow. For stacks having a negative static pressure, seal the sample port sufficiently to prevent air in-leakage around the probe. Set the probe temperature controller to 129'C (265`F) and the filter temperature controller to 121'C (250`F). Allow the probe and filter to heat for about 30 minutes before purging the sample train. 4.1.4.2 Close the sample valve, open the purge valve, and start the vacuum pump. Set the flow rate between 60 and 100 cc/min, and purge the train with stack gas for at least 10 minutes. When the temperatures at the exit ends of the probe and filter are within their specified range, sampling may begin. 4.1.4.3 Check the dry ice level around the condensate trap, and add dry ice if necessary. Record the clock time. To begin sampling, close the purge valve and stop the pump. Open the sample valve and the sample tank valve. Using the flow control valve, set the flow through the sample train to the proper rate. Adjust the flow rate as necessary to maintain a constant rate (+10 percent) throughout the duration of the sampling period. Record the sample tank vacuum and flowmeter setting at 5-minute intervals. (See Figure 25-8.). Select a total sample time greater than or equal to the minimum sampling time specified in the applicable subpart of the regulation; end the sampling when this time period is reached or when a constant flow rate can no longer be maintained because of reduced sample tank vacuum. 4.1.4.4 Note: If sampling had to be stopped before obtaining the minimum sampling time (specified in the applicable subpart) because a constant flow rate could not be maintained, proceed as follows: After closing the sample tank valve, remove the used sample tank from the sampling train (without disconnecting other portions of the sampling train). Take another evacuated and leak-checked sample tank, measure and record the tank vacuum, and attach the new tank to the sampling train. After the new tank is attached to the sample train, proceed with the sampling until the required minimum sampling time has been exceeded. 4.2 Sample Recovery. After sampling is completed, close the flow control valve, and record the final tank vacuum; then record the tank temperature and barometric pressure. Close the sample tank valve, and disconnect the sample tank from the sample system. Disconnect the condensate trap at the flowmetering system, and tightly seal both ends of the condensate trap. Do not include the probe from the stack to the filter as part of the condensate sample. Keep the trap packed in dry ice until the samples are returned to the laboratory for analysis. Ensure that run numbers are identified on the condensate trap and the sample tank (s). 4.3 Condensate Recovery. See Figure 25-9. Set the carrier gas flow rate, and heat the catalyst to its operating temperature to condition the apparatus. 4.3.1 Daily Performance Checks. Each day before analyzing any samples, perform the following tests: 4.3.1.1 Leak Check. With the carrier gas inlets and the sample recovery valve closed, install a clean condensate trap in the system, and evacuate the system to 10 mm Hg absolute pressure or less. Monitor the system pressure for 10 minutes. The system is acceptable if the pressure change is less than 2 mm Hg. 4.3.1.2 System Background Test. Adjust the carrier gas and auxiliary oxygen flow rate to their normal values of 100 cc/min and 150 cc/min, respectively, with the sample recovery valve in vent position. Using a 10-ml syringe withdraw a sample from the system effluent through the syringe port. Inject this sample into the NMO analyzer, and measure the CO₂ content. The system background is acceptable if the CO2 concentration is less than 10 ppm. 4.3.1.3 Oxidation Catalyst Efficiency Check. Conduct a catalyst efficiency test as specified in Section 5.1.2 of this method. If the criterion of this test cannot be met, make the necessary repairs to the system before proceeding. 4.3.2 Condensate Trap CO₂ Purge and Sample Tank Pressurization. 4.3.2.1 After sampling is completed, the condensate trap will contain condensed water and organics and a small volume of sampled gas. This gas from the stack may contain a significant amount of CO2 which must be removed from the condensate trap before the sample is recovered. This is accomplished by purging the condensate trap with zero air and collecting the purged gas in the original sample tank. 4.3.2.2 Begin with the sample tank and condensate trap from the test run to be analyzed. Set the four-port valve of the condensate recovery system in the CO₂ purge position as shown in Figure 25-9. With the sample tank valve closed, attach the sample tank to the sample recovery system. With the sample recovery valve in the vent position and the flow control valve fully open, evacuate the manometer or pressure gauge to the vacuum of the sample tank. Next, close the vacuum pump valve, open the sample tank valve, and record the tank pressure. 4.3.2.3 Attach the dry-ice-cooled condensate trap to the recovery system, and initiate the purge by switching the sample recovery valve from vent to collect position. Adjust the flow control valve to maintain atmospheric pressure in the recovery system. Continue the purge until the CO₂ concentration of the trap effluent is less than 5 ppm. CO₂ concentration in the trap effluent should be measured by extracting syringe samples from the recovery system and analyzing the samples with the NMO analyzer. This procedure should be used only after the NDIR response has reached a minimum level. Using a 10-ml syringe, extract a sample from the syringe port prior to the NDIR, and inject this sample into the NMO analyzer. 4.3.2.4 After the completion of the CO₂ purge, use the carrier gas bypass valve to pressurize the sample tank to approximately 1,060 mm Hg absolute pressure with zero air. 4.3.3 Recovery of the Condensate Trap Sample. 4.3.3.1 See Figure 25-10. Attach the ICV to the sample recovery system. With the sample recovery valve in a closed position, between vent and collect, and the flow control and ICV valves fully open, evacuate the manometer or gauge, the connecting tubing, and the ICV to 10 mm Hg absolute pressure. Close the flowcontrol and vacuum pump valves. 4.3.3.2 Begin auxiliary oxygen flow to the oxidation catalyst at a rate of 150 cc/min, then switch the four-way valve to the trap recovery position and the sample recovery valve to collect position. The system should now be set up to operate as indicated in Figure 25-10. After the manometer or pressure gauge begins to register a slight positive pressure, open the flow control valve. Adjust the flow-control valve to maintain atmospheric pressure in the system within 10 percent. 4.3.3.3 Now, remove the condensate trap from the dry ice, and allow it to warm to ambient temperature while monitoring the NDIR response. If after 5 minutes, the CO₂ concentration of the catalyst effluent is below 10,000 ppm, discontinue the auxiliary oxygen flow to the oxidation catalyst. Begin heating the trap by placing it in a furnace preheated to 200'C. Once heating has begun, carefully monitor the NDIR response to ensure that the catalyst effluent concentration does not exceed 50,000 ppm. Whenever the CO₂ concentration exceeds 50,000 ppm, supply auxiliary oxygen to the catalyst at the rate of 150 cc/min. Begin heating the tubing that connected the heated sample box to the condensate trap only after the CO₂ concentration falls below 10,000 ppm. This tubing may be heated in the same oven as the condensate trap or with an auxiliary heat source such as a heat gun. Heating temperature must not exceed 200'C. If a heat gun is used, heat the tubing slowly along its entire length from the upstream end to the downstream end, and repeat the pattern for a total of three times. Continue the recovery until the CO₂ concentration drops to less than 10 ppm as determined by syringe injection as described under the condensate trap CO₂ purge procedure, Section 4.3.2. 4.3.3.4 After the sample recovery is completed, use the carrier gas bypass valve to pressurize the ICV to approximately 1060 mm Hg absolute pressure with zero air. 4.4 Analysis: Before putting the NMO analyzer into routine operation, conduct an initial performance test. Start the analyzer, and perform all the necessary functions in order to put the analyzer into proper working order; then conduct the performance test according to the procedures established in Section 5.2. Once the performance test has been successfully completed and the CO₂ and NMO calibration response factors have been determined, proceed with sample analysis as follows: 4.4.1 Daily operations and calibration checks. Before and immediately after the analysis of each set of samples or on a daily basis (whichever occurs first), conduct a calibration test according to the procedures established in Section 5.3. If the criteria of the daily calibration test cannot be met, repeat the NMO analyzer performance test (Section 5.2) before proceeding. 4.4.2 Operating Conditions. The carrier gas flow rate is 29.5 cc/min He and 2.2 cc/min O₂. The column oven is heated to 85'C. The order of elution for the sample from the column is CO, CH4, CO2, and NMO. 4.4.3 Analysis of Recovered Condensate Sample. Purge the sample loop with sample, and then inject the sample. Under the specified operating conditions, the CO₂ in the sample will elute in approximately 100 seconds. As soon as the detector response returns to baseline following the CO2 peak, switch the carrier gas flow to backflush, and raise the column oven temperature to 195'C as rapidly as possible. A rate of 30`C/min has been shown to be adequate. Record the value obtained for the condensible organic material (Ccm) measured as CO₂ and any measured NMO. Return the column oven temperature to 85'C in preparation for the next analysis. Analyze each sample in triplicate, and report the average Ccm. 4.4.4 Analysis of Sample Tank. Perform the analysis as described in Section 4.4.3, but record only the value measured for NMO (Cₜₘ). 4.5 Audit Samples. 4.5.1 Analyze a set of two audit samples concurrently with any compliance samples and in exactly the same manner to evaluate the analyst's technique and the instrument calibration. The same analysts, analytical reagents, and analytical system shall be used for the compliance samples and the EPA audit samples; if this condition is met, auditing of subsequent compliance analyses for the same enforcement agency within 30 days is not required. An audit sample set may not be used to validate different sets of compliance samples under the jurisdiction of different enforcement agencies, unless prior arrangements are made with both enforcement agencies. 4.5.2 Calculate the concentrations of the audit samples in ppm using the specified sample volume in the audit instructions. 4.5.3 Note: Indication of acceptable results may be obtained immediately by reporting the audit results in ppm and compliance results in ppm by telephone to the responsible enforcement agency.) Include the results of both audit samples, their identification numbers, and the analyst's name with the results of the compliance determination samples in appropriate reports to the EPA regional office or the appropriate enforcement agency during the 30-day period. 4.5.4 The concentration of the audit samples obtained by the analyst shall agree within 20 percent of the actual concentrations. Failure to meet the 20-percent specification may require retests until the audit problems are resolved. However, if the audit results do not affect the compliance or noncompliance status of the affected facility, the Administrator may waive the reanalysis requirement, further audits, or retests and accept the results of the compliance test. While steps are being taken to resolve audit analysis problems, the Administrator may also choose to use the data to determine the compliance or noncompliance of the affected facility. 5. CALIBRATION AND OPERATIONAL CHECKS Maintain a record of performance of each item. 5.1 Initial Performance Check of Condensate Recovery Apparatus. Perform these tests before the system is first placed in operation, after any shutdown of 6 months or more, and after any major modification of the system, or at the specified frequency. 5.1.1 Carrier Gas and Auxiliary O₂ Blank Check. Analyze each new tank of carrier gas or auxiliary O₂ with the NMO analyzer to check for contamination. Treat the gas cylinders as noncondensible gas samples, and analyze according to the procedure in Section 4.4.3. Add together any measured CH4, CO, CO2, or NMO. The total concentration must be less than 5 ppm. 5.1.2 Catalyst Efficiency Check. 5.1.2.1 With a clean condensate trap installed in the recovery system, replace the carrier gas cylinder with the high level methane standard gas cylinder (Section 3.4.1). Set the four-port valve to the recovery position, and attach an ICV to the recovery system. With the sample recovery valve in vent position and the flow-control and ICV valves fully open, evacuate the manometer or gauge, the connecting tubing, and the ICV to 10 mm Hg absolute pressure. Close the flow-control and vacuum pump valves. 5.1.2.2 After the NDIR response has stabilized, switch the sample recovery valve from vent to collect. When the manometer or pressure gauge begins to register a slight positive pressure, open the flow-control valve. Keep the flow adjusted so that atmospheric pressure is maintained in the system within 10 percent. Continue collecting the sample in a normal manner until the ICV is filled to a nominal gauge pressure of 300 mm Hg. Close the ICV valve, and remove the ICV from the system. Place the sample recovery valve in the vent position, and return the recovery system to its normal carrier gas and normal operating conditions. Analyze the ICV for CO₂ using the NMO analyzer; the catalyst efficiency is acceptable if the CO₂ concentration is within 2 percent of the methane standard concentration. 5.1.3 System Performance Check. Construct a liquid sample injection unit similar in design to the unit shown in Figure 25-7. Insert this unit into the condensate recovery and conditioning system in place of a condensate trap, and set the carrier gas and auxiliary O₂ flow rates to normal operating levels. Attach an evacuated ICV to the system, and switch from system vent to collect. With the carrier gas routed through the injection unit and the oxidation catalyst, inject a liquid sample (See 5.1.3.1 to 5.1.3.4) into the injection port. Operate the trap recovery system as described in Section 4.3.3. Measure the final ICV pressure, and then analyze the vessel to determine the CO₂ concentration. For each injection, calculate the percent recovery using the equation in Section 6.6. The performance test is acceptable if the average percent recovery is 100 ± 10 percent with a relative standard deviation (Section 6.9) of less than 5 percent for each set of triplicate injections as follows: 5.1.3.1 50 µl hexane. 5.1.3.2 10 µl hexane. 5.1.3.3 50 µl decane. 5.1.3.4 10 µl decane. 5.2 Initial NMO Analyzer Performance Test. Perform these tests before the system is first placed in operation, after any shutdown longer than 6 months, and after any major modification of the system. 5.2.1 Oxidation Catalyst Efficiency Check. Turn off or bypass the NMO analyzer reduction catalyst. Make triplicate injections of the high level methane standard (Section 3.4.1). The oxidation catalyst operation is acceptable if the FID response is less than 1 percent of the injected methane concentration. 5.2.2 Reduction Catalyst Efficiency Check. With the oxidation catalyst unheated or bypassed and the heated reduction catalyst bypassed, make triplicate injections of the high level methane standard (Section 3.4.1). Repeat this procedure with both catalysts operative. The reduction catalyst operation is acceptable if the response under both conditions agree within 5 percent. 5.2.3 Analyzer Linearity Check and NMO Calibration. While operating both the oxidation and reduction catalysts, conduct a linearity check of the analyzer using the propane standards specified in Section 3.4.2. Make triplicate injections of each calibration gas, and then calculate the average response factor (area/ppm C) for each gas, as well as the overall mean of the response factor values. The instrument linearity is acceptable if the average response factor of each calibration gas is within 2.5 percent of the overall mean value and if the relative standard deviation (Section 6.9) for each set of triplicate injections is less than 2 percent. Record the overall mean of the propane response factor values as the NMO calibration response factor (RFNMO). Repeat the linearity check using the CO₂ standards specified in Section 3.4.3. Make triplicate injections of each gas, and then calculate the average response factor (area/ppm C) for each gas, as well as the overall mean of the response factor values. Record the overall mean of the response factor values as the CO₂ calibration response factor (RFco₂). The RFco₂ must be within 10 percent of the RFNMO. 5.2.4 System Peformance Check. Check the column separation and overall performance of the analyzer by making triplicate injections of the calibration gases listed in Section 3.4.4. The analyzer performance is acceptable if the measured NMO value for each gas (average of triplicate injections) is within 5 percent of the expected value. 5.3 NMO Analyzer Daily Calibration. 5.3.1 CO₂ Response Factor. Inject triplicate samples of the high level CO2 calibration gas (Section 3.4.3), and calculate the average response factor. The system operation is adequate if the calculated response factor is within 5 percent of the RFco₂ calculated during the initial performance test (Section 5.2.3). Use the daily response factor (DRFco₂) for analyzer calibration and the calculation of measured CO₂ concentrations in the ICV samples. 5.3.2 NMO Response Factors. Inject triplicate samples of the mixed propane calibration cylinder (Section 3.4.4.1), and calculate the average NMO response factor. The system operation is adequate if the calculated response factor is within 5 percent of the RFNMO calculated during the initial performance test (Section 5.2.4). Use the daily response factor (DRFₙ₀) for analyzer calibration and calculation of NMO concentrations in the sample tanks. 5.4 Sample Tank and ICV Volume. The volume of the gas sampling tanks used must be determined. Determine the tank and ICV volumes by weighing them empty and then filled with deionized distilled water; weigh to the nearest 5 g, and record the results. Alternatively, measure the volume of water used to fill them to the nearest 5 ml. 6. CALCULATIONS All equations are written using absolute pressure; absolute pressures are determined by adding the measured barometric pressure to the measured gauge or manometer pressure. 6.1 Nomenclature. C = TGNMO concentration of the effluent, ppm C equivalent. Cc = Calculated condensible organic (condensate trap) concentration of the effluent, ppm C equivalent. C₂ₘ = Measured concentration (NMO analyzer) for the condensate trap ICV, ppm CO2. Cₜ = Calculated noncondensible organic concentration (sample tank) of the effluent, ppm C equivalent. Cₜₘ = Measured concentration (NMO analyzer) for the sample tank, ppm NMO. F = Sampling flow rate, cc/min. L = Volume of liquid injected, µl. M = Molecular weight of the liquid injected, g/g-mole. mc = TGNMO mass concentration of the effluent, mg C/dsm³. N = Carbon number of the liquid compound injected (N = 12 for decane, N = 6 for hexane). P₄ = Final pressure of the intermediate collection vessel, mm Hg absolute. Pb = Barometric pressure, cm Hg. Pₜ₁ = Gas sample tank pressure before sampling, mm Hg absolute. Pₜ = Gas sample tank pressure after sampling, but before pressurizing, mm Hg absolute. Pₜᵣ = Final gas sample tank pressure after pressurizing, mm Hg absolute. Tf = Final temperature of intermediate collection vessel, 'K. Tₜ₁ = Sample tank temperature before sampling, 'K. Tt = Sample tank temperature at completion of sampling, 'K. Ttf = Sample tank temperature after pressurizing, 'K. V = Sample tank volume, m³. Vₜ = Sample train volume, CC. Vv = Intermediate collection vessel volume, m³. V₈ = Gas volume sampled, dsm³. n = Number of data points. q = Total number of analyzer injections of intermediate collection vessel during analysis (where k = injection number, 1 ... q). I = Total number of analyzer injections of sample tank during analysis (where j = injection number, 1 ... r). X₁ = Individual measurements. X = Mean value. P = Density of liquid injected, g/cc. ® = Leak check period, min. AP = Allowable pressure change, cm Hg. 6.2 Allowable Pressure Change. For the pretest leak check, calculate the allowable pressure change: AP 0.01 0.01 Eq. 25-1 6.3 Sample Volume. For each test run, calculate the gas volume sampled: 0.3857 Eq. 25-2 6.4 Noncondensible Organics. For each sample tank, determine the concentration of nonmethane organics (ppm C) : Eq. 25-3 6.5 Condensible Organics. For each condensate trap determine the concentration of organics (ppm C) : Cc = 0.3857 Eq. 25-4 6.6 TGNMO. To determine the TGNMO concentration for each test run, use the following equation: C=Cₜ+Cc Eq. 25-5 6.7 TGNMO Mass Concentration. To determine the TGNMO mass concentration as carbon for each test run, use the following equation: mc=0.4993C Eq. 25-6 6.8 Percent Recovery. To calculate the percent recovery for the liquid injections to the condensate recovery and conditioning system use the following equation: PercentRecovery= 1.604 Eq. 25-7 L P Tf N 6.9 Relative Standard Deviation. RSD = 100/14 (x₁ n-1 2 Eq. 25-8 7. BIBLIOGRAPHY 1. Salo, Albert E., Samuel Witz, and Robert D. MacPhee. Determination of Solvent Vapor Concentrations by Total Combustion Analysis: A Comparison of Infrared with Flame Ionization Detectors. Paper No. 75-33.2. (Presented at the 68th Annual Meeting of the Air Pollution Control Association. Boston, MA. June 15-20, 1975.) 14 p. 2. Salo, Albert E., William L. Oaks, and Robert D. MacPhee. Measuring the Organic Carbon Content of Source Emissions for Air Pollution Control. Paper No. 74-190. (Presented at the 67th Annual Meeting of the Air Pollution Control Association. Denver, CO. June 9-13, 1974.) 25 p. REGULATING VALVE MANOMETER DUAL RANGE ROTAMETER VACUUM PUMP THERMOCOUPLES FLOW CONTROL TEMPERATURE VALVE CONTROLLER H X PURGE VALVE THERMOCOUPLE X SAMPLE TANK SAMPLE VALVE VALVE I X STAINLESS ROTAMETER STEEL FILTER o CONDENSATE HOLDER D : 8 0 TRAP e b STAINLESS STEEL HEATED BOX o PROBE DRY ICE SAMPLE TANK STACK WALL Figure 25-1. Sampling Train SAMPLE VACUUM PUMP SHUT-OFF CONNECTOR VALVE 25.4 1.0 3.175 FIBERFAX INSULATION 0.125 CARTRIDGE CONDENSATE HEATER TRAP PROBE BULKHEAD CONNECTOR mm DIMENSIONS: in FILTER HOLDER PROBE CONNECTOR 152.4 6.0 INSULATED TO TEMPERATURE CONTROLLER PROBE LINE FILTER HEAT CONDENSATE THERMOCOUPLE TEMPERATURE TRAP PROBE CONTROLLER CONNECTOR THERMOCOUPLE THERMOCOUPLE Figure 25-2. Out-of-stack Filter Box 9.5 0.375 316 SS NUT 9.5 OD X 0.375 DIMENSIONS: 0.89 mm WALL 0.035 in 316 SS TUBING 290 11.5 DARSE QUARTZ DOL PACKING 24 r 0.93 57.0