An ASAE/CSAE Meeting Presentation
Paper Number: 044011
Comparison of Source Testing and Boundary Line Testing for Emissions from a Cotton Gin Kevin D. Baker and S. Ed Hughs USDA, ARS, Southwestern Cotton Ginning Research Laboratory PO Box 578, Mesilla Park, NM 88047 E-mail:
[email protected]
Michael Buser USDA, ARS, Cotton Production and Processing Unit Route 3 Box 215, Lubbock, TX 79403
Written for presentation at the 2004 ASAE/CSAE Annual International Meeting Sponsored by ASAE/CSAE Fairmont Chateau Laurier, The Westin, Government Centre Ottawa, Ontario, Canada 1 - 4 August 2004 Abstract. Simultaneous source testing and boundary line testing were conducted at an operating cotton gin in the San Joaquin Valley, California. Results of the simultaneous testing were compared regarding their indication of compliance with air pollution regulations and standards.
Keywords. Cotton ginning, air quality, particulate monitoring
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Introduction Particulate emissions from cotton gins have been a major concern for decades. With gins required to comply with ever-increasingly stringent federal, state, and/or regional air quality regulations, and with compliance measures costing tens to hundreds of thousands of dollars, it is critical that legislators, environmental regulators, researchers, and the ginning industry work together to ensure that regulations are based on sound science and true environmental benefit. In response to potential health hazards posed by particulate matter in the air that can be inhaled, the federal government has developed goals, standards, and regulations that affect cotton gins among a list of many other agricultural and industrial processes. (Buser, et al. 2002). The U.S. Environmental Protection Agency (EPA) has been commissioned with the task of ensuring compliance with federal regulations. Current federal regulations are based upon suspended particulate matter having an aerodynamic diameter of less than ten microns, commonly referred to as PM10. The current National Ambient Air Quality Standard (NAAQS) is 150 µg/m3, averaged over a 24-hour time period. To meet this standard, the EPA has established source testing emission factors for cotton gins and other agricultural and food processes commonly referred to as AP-42 (US EPA, 1996). Both source testing and boundary line testing have their advantages and disadvantages. Source testing is a method to give an accurate indication of emissions at a point in time. For emission conditions that are nearly constant, this is a good indicator. However; if the emissions at the time of testing differ from the long-term average, the results will be greatly misleading. Boundary line testing is generally conducted over a long period of time, with average results being reported. However; boundary line testing can be influenced by nearby emission sources, such as open fields, roads, or other particulate sources nearby. Continuous monitoring systems are currently under development that can due source testing over a long time period (Funk, et al. 2003).
Objective The objective of this study was: • To compare results of simultaneous source testing and boundary line testing at a commercial cotton gin concerning compliance with regulatory standards.
Methods and Materials Source testing Source emission compliance tests for total suspended particles (TSP) and suspended particulate matter having an aerodynamic diameter of less than 10 microns (PM10) was conducted from November 3 through November 6, 2003, on seven emission points at the Westhaven Cotton Company gin, LeMoore, California. The seven emission points included the number one pre-cleaning cyclone, the number two pre-cleaning cyclone, the motes cyclone, the motes transfer cyclone, the overflow cyclone, the number one lint cleaner cyclone, and the battery condenser cyclone. Westhaven Cotton Company’s personnel recorded bale production data from which production rates were calculated. Emissions testing was conducted by AIRx Testing, Madera, California. An EPA method 201A sampling train was used to determine TSP and PM10 emissions from each cyclone. The sampling train consisted of a stainless steel nozzle, a stainless steel cyclone
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separator, a glass fiber filter, a stainless steel probe, and cooled impingers. After the weight was obtained from the filter, probe, and nozzle rinses, the weight of total solids in the impingers was added to the front-end catch to satisfy San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) rules for TSP. Exhausts for each cyclone were routed to ground level using duct work (commonly referred to as a candy cane). Testing was conducted through 2 sample ports at right angles to each other. The ports were located at least two duct diameters upstream and eight duct diameters downstream from the nearest flow disturbance. Twelve sample points (six per port) were taken sample run. Sample runs were repeated three times for each cyclone before moving to the next one. A sample was taken iso-kinetically from each cyclone exhaust using an Anderson PM10 cyclone separator. The total weights obtained from each fraction were added together to obtain the total particulate weight. The total weight was used to determine the percentage of the +10 micron and the -10 micron fraction. The exhaust gas was assumed to be ambient air with 20.9% oxygen and 0.05% carbon dioxide. Exhaust velocity was determined using an S-type pitot tube connected to an inclined manometer. This was done for each test using twelve traverse points within each duct. Stack temperature was determined using a thermocouple and an indicating pyrometer. The moisture content was determined gravimetrically and the dry molecular weight was determined by CARB method 3. Velocities and volumetric flow rates were calculated using CARB method 2. All values were calculated using SJVUAPCD standard conditions of 60oF and 29.92 in. Hg. No problems were encountered during the sampling. All glassware was inspected before and after each test to ensure that no breakage had occurred during the sampling. Leak rate checks were conducted on the sampling train (at the nozzle) and the pitot tubes before and after each test. Any leak rate greater than 0.02 cfm was corrected for in the volume calculations.
Boundary line testing Boundary line testing for TSP was conducted from November 4 to November 7, 2003, at 4 locations, one each on the north, south, east, and west boundaries of the gin yard. One PM10 sampler was also installed; however, the PM10 sampler malfunctioned and no data was obtained from it. Meteorological data were obtained from a weather station at a naval air base adjacent to the gin. Hourly readings for air temperature, dew point temperature, barometric pressure, and wind speed and direction were obtained and used in the data analysis. Each TSP sampler consisted of an air vacuum pump that drew air in through a filter that was shielded from rain. A valve in the system was used to adjust the airflow to approximately 0.59 cfm, based on the pressure drop across an orifice plate in the air line. Pressure drop across the orifice and current draw by the air pump were recorded at 30 second intervals during the test. Each sampler operated for about 8 hours before the filters were changed. Changing the filters required about 5 minutes of down time every 8 hours. Samplers were powered by gasoline generators located about 50 feet from them. Blank sample filters were conditioned at 70oF and 65%rh, then weighed and placed in a covered Petri dish. Just prior to their use, the filters were transferred from the Petri dish to the sampler filter holder in the laboratory, and the sampler filter holders were placed in a covered box for transport. An extra filter and filter holder were used to determine if extraneous dust was captured during transport. Dirty filters were transported back to the laboratory and then reconditioned at the same air conditions before final weighing. A Mettler model HL52 analytical balance was used to weigh the filters with weight recorded to the nearest 0.00001 gram.
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After weighing, sample filters were carefully transported to the USDA, Agricultural Research Service, Cotton Production and Processing Research Unit, Lubbock, Texas. TSP samples were analyzed for particle size distribution using a Coulter Counter Multisizer III.
Results and Discussion Data is currently being analyzed and will be presented at the meeting. For further information, contact the principal author after the meeting.
Conclusions Conclusions will be presented at the 2004 ASAE/CSAE meeting in Ottawa.
References Buser, M.D., Parnell, C.B. Jr., R.E. Lacey, and B.W. Shaw. 2002. PM10 sampler errors due to the interaction of particle size and sampler performance characteristics. Proceedings of the 2002 Beltwide Cotton Conferences, Atlanta, Georgia. National Cotton Council, Memphis, Tennessee. Funk, P.A., K. D. Baker, S.E. Hughs, and G.A. Holt. 2003. Evaluating an on-line dust cyclone performance monitor. Proceedings of the 3rd International Conference on Air Pollution from Agricultural Operations. Durham, North Carolina. ASAE, St. Joseph, Michigan. U.S. Environmental Protection Agency. 1996. Interim AP-42 emission factors for the agricultural and food industry. Research Triangle Park, North Carolina.
Disclaimer Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and neither implies recommendation nor endorsement by the U.S. Department of Agriculture.
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