AIR POLLUTION CONTROL TECHNOLOGY HANDBOOK - CHAPTER 5 potx

TABLE 5.1 Code of Federal Regulations Source Test Methods 1 Sample and velocity traverses for stationary sources 1A Sample and velocity traverses for stationary sources with small stacks

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Source Testing

5.1 INTRODUCTION

Source testing is measuring the air pollutant concentration and/or quantity at a source

or stack The terminology implies using test methods to measure concentration on

a one-time or snapshot basis, as opposed to continuously monitoring the source as discussed in Chapter 6 Source testing may be performed to provide design data or

to measure performance of a process, or it may be prescribed on a periodic basis to demonstrate compliance with air permit emission limitations Most source test pro-cedures require labor to set up the test, collect samples, and analyze the results

5.2 CODE OF FEDERAL REGULATIONS

The gospel of source testing is the Code of Federal Regulations, 40 CFR Part 60, Appendix A.1 Very specific test procedures with step-by-step instructions are detailed

in the CFR A list of source test methods that are described in the CFR is provided

in Table 5.1 These procedures have been tested, reviewed, and adopted by the EPA

as the reference source test methods for a number of pollutants in a variety of applications The universality of these test methods makes it easy for those practicing

in the field to know just how a source test was conducted, and understand its limitations, just by giving a shorthand reference such as “Method 8.”

Of course, the CFR test methods cannot be applied to all possible applications because it would have been impossible to evaluate and fund the research required for all circumstances It would be an inefficient use of public funds for the EPA to sponsor research for test methods that cover unusual operating conditions for a unique process, and it is impossible to predict future processes, conditions, and improvements Sometimes experience, judgment, and skill are needed to modify the test method to overcome a limitation that arises in a specific application In such cases, test reports can reference the test method and describe the modification

5.3 REPRESENTATIVE SAMPLING TECHNIQUES 5.3.1 G ASEOUS P OLLUTANTS

One of the fundamentals in source testing for air contaminants is to obtain a representative sample of the gas stream This is easy to do for gaseous pollutants, since molecules of gas can be assumed to be evenly distributed throughout the gas stream due to mixing and diffusion It is highly unlikely that gaseous pollutants will segregate in a moving gas stream A simple probe can be used to withdraw a sample Due care must be used to avoid pulling a sample from a nonrepresentative location, such as just downstream of an injection point

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TABLE 5.1 Code of Federal Regulations Source Test Methods

1 Sample and velocity traverses for stationary sources 1A Sample and velocity traverses for stationary sources with small stacks or ducts

2 Determination of stack gas velocity and volumetric flow rate (Type S pitot tube) 2A Direct measurement of gas volume through pipes and small ducts

2B Determination of exhaust gas volume flow rate from gasoline vapor incinerators 2C Determination of stack gas velocity and volumetric flow rate in small stacks or ducts (standard

pitot tube) 2D Measurement of gas volumetric flow rates in small pipes and ducts

3 Gas analysis for carbon dioxide, oxygen, excess air, and dry molecular weight 3A Determination of oxygen and carbon dioxide concentrations in emissions from stationary

sources (instrumental analyzer procedure)

4 Determination of moisture content in stack gases

5 Determination of particulate emissions from stationary sources 5A Determination of particulate emissions from the asphalt processing and asphalt roofing

industry 5B Determination of nonsulfuric acid particulate matter from stationary sources 5C Reserved

5D Determination of particulate emissions from positive-pressure fabric filters 5E Determination of particulate emissions from the wool fiberglass insulation manufacturing

industry 5F Determination of nonsulfate particulate matter from stationary sources 5G Determination of particulate emissions from wood heaters from a dilution tunnel sampling

location 5H Determination of particulate emissions from wood heaters from a stack location

6 Determination of sulfur dioxide emissions from stationary sources 6A Determination of sulfur dioxide, moisture, and carbon dioxide emissions from fossil-fuel

combustion sources 6B Determination of sulfur dioxide and carbon dioxide daily average emissions from fossil-fuel

combustion sources 6C Determination of sulfur dioxide emissions from stationary sources (instrumental analyzer

procedure)

7 Determination of nitrogen oxide emissions from stationary sources 7A Determination of nitrogen oxide emissions from stationary sources — ion chromatographic

method 7B Determination of nitrogen oxide emissions from stationary sources (ultraviolet

spectrophotometry) 7C Determination of nitrogen oxide emissions from stationary sources —

alkaline-permanganate/colorimetric method 7D Determination of nitrogen oxide emissions from stationary sources —

alkaline-permanganate/ion chromatographic method 7E Determination of nitrogen oxide emissions from stationary sources (instrumental analyzer

method)

8 Determination of sulfuric acid mist and sulfur dioxide emissions from stationary sources

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9 Visual determination of the opacity of emissions from stationary sources

9 Alt 1 Determination of the opacity of emissions from stationary sources remotely by LIDAR

10 Determination of carbon monoxide emissions from stationary sources 10A Determination of carbon monoxide emissions in certifying continuous emission monitoring

systems at petroleum refineries 10B Determination of carbon monoxide emissions from stationary sources

11 Determination of hydrogen sulfide content of fuel gas streams in petroleum refineries

12 Determination of inorganic lead emissions from stationary sources 13A Determination of total fluoride emissions from stationary sources — SPADNS zirconium

lake method 13B Determination of total fluoride emissions from stationary sources — specific ion electrode

method

14 Determination of fluoride emissions from potroom roof monitors for primary roof monitors

for primary aluminum plants

15 Determination of hydrogen sulfide, carbonyl sulfide, and carbon disulfide emissions from

stationary sources 15A Determination of total reduced sulfur emissions from sulfur recovery plants in petroleum

refineries

16 Semicontinuous determination of sulfur emissions from stationary sources 16A Determination of total reduced sulfur emissions from stationary sources (impinger technique) 16B Determination of total reduced sulfur emissions from stationary sources

17 Determination of particulate emissions from stationary sources (in-stack filtration method)

18 Measurement of gaseous organic compound emissions by gas chromatography

19 Determination of sulfur dioxide removal efficiency and particulate, sulfur dioxide, and

nitrogen oxides emission rates

20 Determination of nitrogen oxides, sulfur dioxide, and diluent emissions from stationary gas

turbines

21 Determination of volatile organic compound leaks

22 Visual determination of fugitive emissions from material sources and smoke emissions from

flares

23 Determination of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans from

stationary sources

24 Determination of volatile matter content, water content, density, volume solids, and weight

solids of surface coatings 24A Determination of volatile matter content and density of printing inks and related coatings

25 Determination of total gaseous nonmethane organic emissions as carbon 25A Determination of total gaseous organic concentration using a nondispersive infrared analyzer

26 Determination of hydrogen chloride emissions from stationary sources

27 Determination of vapor tightness of gasoline delivery tank using pressure–vacuum test

28 Certification and auditing of wood heaters 28A Measurement of air-to-fuel ratio and minimum achievable burn rates for wood-fired

appliances

TABLE 5.1 (continued) Code of Federal Regulations Source Test Methods

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The primary consideration for gaseous pollutant sampling is that the sample is not contaminated, or decontaminated, by incompatibility with the materials of the sampling device or container Teflon, stainless steel, and glass sample lines and containers often are used to avoid reactions with pollutants

5.3.2 V ELOCITY AND P ARTICULATE T RAVERSES

Volumetric flow rate in a duct or stack is measured using a pitot tube to detect the difference between the static and dynamic pressure difference created by the velocity head at several points in the duct Details of the tip of a pitot tube are shown in

Figure 5.1 The measured pressure difference is used to calculate velocity The key

is to position the pitot tube at the correct points in the duct so that the average velocity is determined This is done by positioning the pitot tube at the centroid of equal-area segments of the duct Method 1 (CFR) provides tables for probe positions based on this principle Figure 5.2 is an example of sampling points for a circular stack cross section Figure 5.3 is an example for a rectangular duct Note that the two lines of sampling points lie at 90° For a circular duct, this requires at least two sampling ports at 90° For small diameter stacks, the pitot tube can reach across the stack to pick up the points on the far side For large diameter stacks, it is easier to reach no more than half way across the stack, so four sampling ports are provided

to allow shorter sampling probes

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Similarly, because each sampling position is representative of a small area of the duct or stack, particulate samples are withdrawn at the same traverse points at which velocity measurements are made However, because particles do not neces-sarily follow the streamlines of gas flow and because gravity can act on particles in

a horizontal duct, Method 1 recommends more traverse points for particulate sam-pling than for a simple velocity traverse The minimum number of sample points for traverses depends on the proximity of the test port to flow disturbances in the duct, and to a lesser extent, the duct size The minimum number of sample points for a velocity traverse is illustrated in Figure 5.4 The minimum number of samples

to be taken for a particulate traverse is illustrated in Figure 5.5

5.3.3 I SOKINETIC S AMPLING

Extracting a particulate sample from a moving gas stream using a probe in a duct requires that the sample be taken at the same velocity as the gas flow, i.e., isokinet-ically If the velocity of the sample is higher than that of the gas flow, then excess

into 12 equal areas with the location of traverse points indicated.

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gas moving toward the probe will divert toward the probe and be collected with the sample Meanwhile, particles with sufficient momentum will tend to continue trav-eling in a straight line, leaving the gas flow streamlines and will not be carried into the sampling probe, as illustrated in Figure 5.6a This produces a sample that, after measuring the collected gas volume and weighing the collected particulate filter, has

an erroneously low particulate concentration Similarly, if the sample velocity is too low, excess gas is diverted away from the probe while particles are carried into the probe, as illustrated in Figure 5.6b, resulting in an erroneously high particulate concentration

The correct isokinetic sample flow rate is determined by conducting a velocity traverse prior to collecting a particulate sample During the particulate sample, the

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collected gas volume is measured with a gas meter After the sample is taken and

as data are being evaluated, the sample velocity as a percentage of gas velocity is determined and reported as a quality check on the particulate sample

REFERENCES

Register, National Archives and Records Administration, Washington, D.C., July 1, 1993.

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