Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 3/5/2008
Publication Date: 5/29/2008
Citation: Baker, K.D. 2008. Air temperature distribution in seed cotton drying systems. National Cotton Council Beltwide Cotton Conference, January 8-11, 2008, Nashville, TN. 2008 CDROM.
Interpretive Summary: In order to improve the effectiveness of cleaning equipment, cotton is generally dried with heated air as it first enters the gin. Tests were conducted to check for temperature variation within ten cotton drying systems. The tests were conducted in west Texas, the San Joaquin Valley, California, and other western U.S. locations. Air temperature variation along the length of the drying system showed that the most drying occurred within the first 6 feet of when the heated air mixed with the cotton. Recommendations for location of temperature control sensors made by a professional engineering society appear satisfactory, based upon this data, but some improvements could be made. Results for air temperature variation within the heated air stream before it is used for drying indicated that some systems had a temperature difference of 100 oF or more. Temperature differences this large would result in uneven drying and less effective cleaning. Further testing should be done that would investigate methods of reducing the temperature variation for drying systems with problems in that area.
Technical Abstract: Ten tests were conducted in the fall of 2007 to measure air temperature variation within various heated air seed cotton drying systems with the purpose of: checking validation of recommendations by a professional engineering society and measuring air temperature variation across the airflow ductwork preceding the mixpoint of heated air seed cotton drying systems with the purpose of checking for large temperature differences that may exist. The cooperating gins were located in west Texas, the San Joaquin Valley, California, and other locations in the western U.S. Drying systems tested include: pipe-fed tower, pipe, crossflow blow-box, hi-slip, fountain – collider type, and jet systems. Regarding air temperature variation along the conveying length of the seed cotton drying systems, all but one of the ten systems had the largest temperature drop in the first 6.5 feet (2 m) after the mixpoint. For all systems, the temperature drop in the first 6.5 feet (2 m) after the mixpoint was significant enough that locating a temperature control sensor at that location would achieve satisfactory control. The recommendations that were being checked appear to be satisfactory, but can be improved upon. Regarding air temperature variation across the airflow ductwork preceding the mixpoint of heated air seed cotton drying systems, three of the ten systems tested had significant variation in air temperature, ranging up to a temperature difference of 120 oF (67 oC) among the four locations tested. Drying systems which dispersed the drying air across large widths (up to 8 feet or 2.5 m), such as the crossflow blow-box and the hi-slip drying systems, were more likely to have a large variation than were systems which kept the drying air concentrated, such as the pipe, jet, and pipe-fed tower drying systems. Further testing should be done that would investigate methods of reducing the temperature variation for drying systems with problems in that area.