New Mexico Administrative Code
Title 20 - ENVIRONMENTAL PROTECTION
Chapter 2 - AIR QUALITY (STATEWIDE)
Part 14 - PARTICULATE EMISSIONS FROM COAL BURNING EQUIPMENT
Section 20.2.14.401 - PROCEDURE II, METHOD

(1) Sampling Train:

(2) Nozzle: Stainless steel (type 304 or 316).

(3) Probe: Pyrex glass, insulated and heated uniformly to a temperature sufficient to prevent condensation from occurring at any point in the tube. For lengths greater than about 8 feet, a metal tube may be used. Incoloy 825 is preferred, but types 304 or 316 stainless steel are acceptable. Long probes shall be reinforced or supported to prevent excessive droop or gas stream whip. For sampling stacks carrying electrically charged particles (as for installations using electrostatic precipitators), the probe shall be grounded to prevent electrical shock to personnel and the inner shell of the probe shall be electrically conductive and shall be grounded to prevent size discriminative trapping of particles within the probe.

(4) Particulate Separator: The particle collector shall be heated so that the temperature of the collection plates and back up filter is above the dew point of the stack gases.

(5) Particle Collector: The particle collector shall be a cascade impactor, such as the Andersen Mark III Stack Sampler (Mark III sampler) manufactured by 2000 Inc., Atlanta, Georgia or other similar cascade impactor approved by the Department. The Mark III Sampler shall use a complete set of collector plates consisting of the following: Ten plates numbered 0, 1, 2, 3, 4, 5, 6, 7, 8, and F, eleven spacers, eight crossbars, eight glass fiber collection discs, one glass fiber filter, and one plate holder. Collector plates are installed as follows; 0, 1, 2, 3, 4, 5, 6, 7, 8, F. The complete arrangement is shown in Figure 2 (20.2.14.403 NMAC). The gas flowrate through the Mark III Sampler must be controlled to maintain a particle impaction efficiency of 50% on plate 4 for particles of 2 microns aerodynamic diameter. The procedure for doing this is described in paragraphs (4) and (5) of subsection D of 20.2.14.401 NMAC.

(6) Metering System: Vacuum gage, leak-free pumps, thermometers capable of measuring to within 3 degrees Fahrenheit., dry test meter with 2 percent accuracy, and related equipment, as required to maintain an approximately isokinetic sampling rate through the probe and specified flowrate through the Mark III Sampler, and to determine sample volume.

(7) Other Sampling Train Equipment: Pitot tube (type S, or equivalent), impingers/condensers, and barometer shall be as specified in US EPA method 5, Section 2.1. Note that an equivalent condenser may be used in place of the impinger train.

(8) Sample Recovery Accessories: As specified in US EPA Method 5, Section 2.2.

(9) Analytical Accessories: As specified in US EPA Method 5, Section 2.3.

(1) Sampling: Sampling for total particulate mass loading shall be in accordance with US EPA Method 5. Procedures for determining the percent by mass of particles less than two microns equivalent aerodynamic diameter shall be as follows.

(2) Filters: Glass fiber type, having high efficiency for collecting small particles (99% or higher efficiency for particles 0.3 microns or larger in diameter). Cambridge Media CM-114 or Gelman Type A filters are acceptable types.

(3) Other Sampling Reagents: As specified in US EPA Method 5, Section 3.1.

(4) Sample Recovery and Analytical Reagents: Acetone and water, as specified in US EPA Method 5, Sections 3.2 and 3.3.

(1) Procedures: Sampling procedures for total particulate mass loading shall be in accordance with US EPA Method 5. Procedures for determining the percent by mass of particles less than two microns equivalent aerodynamic diameter shall be as follows.

(2) Selection of Sampling Site and Sampling Points: The sampling site is preferably located in a vertical duct or stack, at least eight stack diameters downstream and two diameters upstream of a major disturbance (bend, expansion, contraction or visible flame). In large ducts (of 20 feet or grater diameter), a distance five diameters downstream of a disturbance will be considered adequate, providing the velocity traverse does not show the flow to be highly irregular. Under these recommended conditions, a single sampling point is considered to be adequate (See Industrial Gas Cleaning Institute, Test Procedures for Gas Scrubbers, Publication No. 1, p.6): This point shall be located between 0.2 and 0.5 of the diameter from the outside toward the center of the stack, preferably at a point whose velocity approximates the average velocity of the flue gases. For conditions which do not meet the criteria given above, additional sampling points must be considered and will be determined as agreed upon between the coal burning equipment operator and the Department.

(3) Determination of Stack, Pressure, Temperatures, Moisture and Distribution of Velocity Heads: Prior to actual sampling for particulates, a preliminary survey of stack pressure, temperatures, moisture content, and velocity distribution shall be made to assess overall sampling conditions and establish isokinetic sampling velocities.

(4) Preparation of Collection Train: Check to see that the probe, nozzle, etc., are clean and that there is sufficient ice to fill the ice bath, place 100 ml. of water in the first two impingers, leave the third impinger empty, and place approximately 200 g. of preweighed indicating silica gel in the fourth impinger. Complete the preparation by desiccating the filter, checking the train for leaks and adjusting the probe heater, generally as specified in the US EPA Method 5, Section 4.1.2. To establish near isokinetic sampling conditions at the start of testing, the desired flowrate through the particle separator is corrected to stack conditions and the desired sample nozzle size is calculated. To do this record the temperature of the in-stack Mark III Sampler. Find this temperature in the abscissa of the graph on Figure 3 (20.2.14.404 NMAC), go up to the curve and read the correction factor on the ordinate of the graph. Multiply the correction factor by two microns and obtain the temperature corrected aerodynamic diameter. Locate the corrected aerodynamic diameter on the abscissa of the graph on Figure 4 (20.2.14.405 NMAC) go up to the curve and read on the ordinate the flowrate needed to maintain an impaction efficiency of 50% on plate #4. Correct this flowrate to stack conditions by adjusting for the difference in particle separator temperature and stack temperature. Using the equation Q = VA where Q = volumetric flowrate through the separator adjusted to stack temperature (cfm), V = velocity of the stack gas at the point in the stack where the sampling is to take place (fpm) and A is area of the nozzle (sq. ft.) calculate the desired sampling nozzle diameter. Attach a nozzle to the probe that matches this calculated diameter within 1%. To establish at the start of testing the correct gas flow through the separator, using the dry gas meter, correct the desired flowrate through the separator to meter conditions by correcting for the difference in temperature between the separator and the dry gas meter and subtract out that portion of the gas volume which will be condensed in the impingers.

(5) Particulate Train Operation: To begin sampling, position the nozzle at the selected point in the stack with the nozzle tip pointing directly into the gas stream. Immediately after, start the pump and adjust the dry gas meter to the flowrate calculated in paragraph (4) of subsection D of 20.2.14.401 NMAC. Sample for at least 5 minutes and then record the temperature of the gas on the outlet end of the separator. If the temperature is different from that of the container surrounding the separator readjust the dry gas meter flowrate by repeating the steps described in paragraph (4) of subsection D of 20.2.14.401 NMAC using Figures 3 (20.2.14.404 NMAC) and 4 (20.2.14.405 NMAC) excluding the step used in calculating nozzle diameter. Continue the run until 30 standard cubic feet (70 degrees Fahrenheit, 29.92 inches Hg) have been drawn through the sampling train. For each run record the required data on a sheet such as the one shown in Figure 5-2 of the US EPA Method 5 and include the temperature monitored at the outlet of the separator. Record the data after every 5 minutes of testing. At the end of the run, turn off the pump and record the final readings. Remove the probe and nozzle from the stack. Remove the filter and glass fiber collection discs from the separator and place each in a separate container. Collect in a container all particles brushed and washed from the nozzle, the impactor inlet cone and the zero stage plate. Repeat the sampling procedure until three runs have been obtained. Filter wash-solution and dry filter. Desiccate the filters and collection discs for at least 24 hours and weigh to the nearest 0.5 mg in a room where the relative humidity is less than 50%.

(1) Total Particulate Emissions: After completing the test series, average the dry gas meter temperatures and average orifice pressure drops, then correct the sample volumes measured to standard conditions and calculate the water vapor and moisture content. Using data gathered, using US EPA Method 5, calculate the concentration of total particulate matter in the stack gas in pounds per standard cubic foot on a dry basis by using equation 5-5 given in Section 6.6.2 of US EPA Method 5. Using the stack volumetric flowrate corrected to standard conditions on a dry basis calculate the emission rate in pounds per hour. Using the average heat input to the coal burning equipment during the time of testing, in millions of British Thermal Units per hour, calculate the emission rate in pounds per million British Thermal Units. Average the emission rate for the three runs to determine total particulate emissions.

(2) Percent of Particles Less Than Two Microns: The data obtained from the Mark III Sampling shall be used to determine the quantity of particulate matter larger than two microns Equivalent Aerodynamic Diameter and the quantity of particulate matter less than two microns Equivalent Aerodynamic Diameter. Particulate matter larger than two microns equivalent aerodynamic diameter shall be defined to be the particulate matter collected on the glass fiber collection discs from plates numbered 1, 2, 3, and 4 and the material brushed and washed from the nozzle, the impactor inlet cone and the zero stage plate. Particulate matter less than two microns equivalent aerodynamic diameter shall be defined to be the particulate material collected on the glass fiber collection discs from plates numbered 5, 6, 7 and 8 and the particulate matter collected on the glass fiber filter. The sum of the mass' of the particulates which are greater than two microns Equivalent Aerodynamic Diameter and the particles less than two microns equivalent aerodynamic diameter is the total particulate collected for the purposes of determining percent less than two microns. After determining the quantity of particulate collected, determine the percent by mass of the total particulate collected which is compassed of particles of less than two microns equivalent aerodynamic diameter.

(3) Loading of Particles Less Than Two Microns: The percentage by mass of particles as determined from the Mark III sampling results as described in the previous paragraph is applied to the total mass loading in pounds per million British Thermal Units as determined by US EPA Method 5. The resulting loading in pounds per million British Thermal Units of particulates less than two microns equivalent aerodynamic diameter shall be used to determine compliance with the particulate emission limitations contained in subsection B of 20.2.14.202 NMAC and subsection B of 20.2.14.203 NMAC.