HARVESTING AND GINNING PROCESSES TO ENHANCE THE PROFITABILITY OF STRIPPER COTTON
Location: Cotton Production and Processing Research
Title: Evaluation of select equipment sequences for optimal fiber recovery from stripper harvested gin waste
Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 15, 2011
Publication Date: April 20, 2011
Citation: Holt, G.A., Simonton, J., Wanjura, J.D., Knabb, C., Pelletier, M.G., Wedegaertner, T. 2011. Evaluation of select equipment sequences for optimal fiber recovery from stripper harvested gin waste. Journal of Cotton Science. 15(1):43-51.
Interpretive Summary: Previous research studies focusing on segregation of cotton gin byproducts (gin waste or gin trash) into its various components revealed the quantity of recoverable fibers to be in the range of 10 to 25 percent by weight. For cotton gins processing bur-extracted stripper harvested cotton, this would equate to 40 to 100 lbs of lint per bale. As a result of the previous studies, several cotton ginners inquired as to the best equipment layout that would reclaim the most marketable "clean" fiber. This study investigated nine different equipment layouts using separators, cylinder cleaners, and stick machines (also known as extractors) to see if there was a machinery layout that significantly reclaimed and cleaned the fibers in the gin waste more than others. Results from the study show the layouts using only cylinder cleaners did not sufficiently clean the fibers compared to the machinery setups that contained stick machines. The setups that did the best job of reclaiming marketable fibers were those that contained extractors. An economic analysis was performed using a range of capital costs of $90k to $240k, assuming a fiber selling price of $0.05 to $0.15/lb, and fiber recovery yields of 5% to 15% by weight of gin waste processed. The economics were evaluated for gins processing 20,000 to 80,000 bales/year. Overall, the fibers recovered are suitable for inclusion into mote bales but not lint bales since they contain small amounts of seedcotton as well as significant amounts of short fibers, 23 to 30 percent by weight. For gins with 20,000 bales/year, recovery rates of 9% plus motes prices greater than $0.09/lb are necessary for positive cash flows. The payback for gins processing more than 20,000 bales/year was desirable. Given current economic conditions of higher input costs and lower prices for cotton, producers and ginners need to take advantage of every possible source of revenue available from the crop. Reclaiming the fibers traditionally left in gin waste has real potential as a revenue generator while reducing the volume of waste being generated.
Previous studies have shown that the quantity of recoverable fibers with the potential to be marketed as motes approaches 10 to 25% of gin trash by weight. As a result of these findings and of practical experience from a commercial cotton gin, questions arose as to the best equipment setup needed to recover the largest quantity of mote quality fibers. In this study, nine machinery layouts were evaluated to determine the setup that produced the largest quantity of marketable fibers. The machinery layouts evaluated included gravity feeding, separators, cylinder cleaners, and extractors (stick machines). Results indicated that the setups that produced the cleanest marketable fibers were ones that contained at least one extractor (stick and bur machine). In addition, AFIS (Advanced Fiber Information System) data was also obtained on all fibers reclaimed from each layout. The AFIS data revealed short fiber contents ranging from 23 to 30% by weight and 53 to 63% by number and indicated significant differences (p-value less than or equal to 0.05) for some of the fiber properties. Given that the fibers recovered are intended for inclusion into mote bales and not lint bales, the AFIS data did not indicate one machinery layout to be more desirable than another. An economic analysis using a range of reclaimed fiber prices, ginning capacities and fiber recovery rates suggests desirable potential revenues for gins of 40,000 bales/yr and higher are possible.