Submitted to: Ph D Dissertation
Publication Type: Other
Publication Acceptance Date: 9/27/2004
Publication Date: 12/18/2004
Citation: Holt, G.A. 2004. Optimization of fiber quality, production rate, and lint turnout for the powered roll gin stand utilizing response surface methodology and desirability functions [Ph.D. Dissertation]. Lubbock, TX: Texas Tech University. 330 p. Interpretive Summary: The powered roll gin stand was initially developed to regin cottonseed in order to remove as much residual lint as possible for the EasifloTM process. Over the past few years, various studies have been conducted evaluating its use in ginning seed cotton. This study reports on two separate studies on different makes and models of gin stands (Lummus-116 and Continental Double Eagle-141) in order to optimize the powered roll gin stand's operational components for optimal production rate, lint turnout, and fiber properties while ginning seed cotton. This report covers the results from two optimization studies, two validation studies, four comparison studies, and an economic evaluation based on the results obtained. Results from the optimization and validation studies indicate various optimal settings depending on the emphasis placed on the various response variables. For example, when AFIS length, short fiber content, ginning rate, and Rd were the main inputs into the desirability functions for the Continental-141, the optimal setting was: paddle roll speed = 230 rpm, paddle roll load = 25 amps, and seed finger speed = 10 rpm. However, when all thirteen response variables were used as inputs into the desirability function, the optimal setting was: paddle roll speed = 180 rpm, paddle roll load = 23.8 amps, and seed finger speed = 40 rpm. These responses indicate the compromise that exists with any optimization procedure. Overall, the power roll gin stand demonstrated the potential for improvements in processing rate, lint turnout, and preserving fiber properties. Likewise, the power roll gin stand has the potential to be utilized in real-time process control applications to allow the possibility for "prescription ginning" based on the quality of the incoming seedcotton.
Technical Abstract: The power roll gin stand is a new saw gin technology developed at the United States Department of Agriculture - Agricultural Research Service's cotton ginning laboratory in Lubbock, Texas. The technology was initially developed to regin cottonseed to solve processing problems with a cottonseed coating process (EasifloTM). Evaluation of the fiber properties from reginning the cottonseed indicated the potential for this technology to be utilized for ginning seed cotton. Since then, numerous studies have been conducted evaluating the power roll gin stand's potential for ginning seed cotton. Past results have shown increased production and lint turnout without adversely affecting fiber properties, and in some cases, improvements in fiber properties over conventional gin stands were demonstrated. However, a majority of the initial studies were conducted at operational settings that were optimal when reginning cottonseed and not seed cotton. The power roll gin stand consists of three main components: paddle roll, saw, and seed finger roll. The operational settings of speed and/or loading rate at which these components operate influence fiber properties and/or processing rate, items which are important to either the producer, cotton gin management, and/or textile mills. This dissertation reports on two studies, on different makes of gin stands, to optimize the power roll gin stand's operational components for optimal production rate, lint turnout, and fiber properties in the ginning of seed cotton. The optimizations were performed using response surface methodology and desirability functions. Since the power roll gin stand is a new technology, understanding how the various components of the gin stand can be manipulated to enhance operational performance while preserving fiber properties is paramount to successful implementation of this technology in the cotton ginning industry. The first study consisted of a prototype Lummus-116 gin stand located at the United States Department of Agriculture - Agricultural Research Service's gin lab in Lubbock, Texas. The second gin stand was installed in a commercial cotton gin and operated during the 2003 ginning season in Courtland, Alabama. Results from the studies produced several optimal solutions depending on the response variables evaluated and the weighting factors used in the desirability functions. Once the optimization studies were completed, validation and comparison studies were conducted. Validation studies evaluated the results obtained from the optimization studies while the comparison tests were performed versus conventional gin stands to see if the optimized gin stand performed to expectations. Results from these studies indicated some improvements over conventional gin stands in fiber properties, lint turnout, and/or processing rate. Overall, the power roll gin stand has demonstrated the potential for improvements in processing rate, lint turnout, and preserving fiber properties. Likewise, the power roll gin stand has the potential to be utilized in real-time process control applications where the gin stand is dynamically adjusted to produce optimum fiber properties based on the quality of the seed cotton being ginned. Being able to dynamically adjust the gin stand while ginning seed cotton allows the possibility of "prescription ginning" at the very heart of the cotton gin, the gin stand.