Location: Cotton Ginning Research2011 Annual Report
1a. Objectives (from AD-416)
Our goal is to increase the profitability of the U.S. cotton production system through new and improved cotton ginning equipment and processes resulting in enhanced market value and utility of ginned cotton lint in the global market. We will focus on the following objectives: 1) Refine the design, operation, and management of existing cotton ginning machinery to increase productivity and reduce short fiber content, neps, and seed coat fragments; 2) Improve cotton gin processing by comprehensively investigating the impact of cotton cultivar on fiber quality and non-lint content and develop improved relationships between measurable cotton traits and the value of the final products; 3) Improve automated measurement of relevant properties and control of gin processes for more efficient management, especially related to moisture, fiber quality, and energy use; and 4) Optimize the entire ginning system from module to bale, particularly related to air quality issues, energy use, and control of cotton moisture content.
1b. Approach (from AD-416)
The objectives are interrelated and success in one contributes to success in another. Improved measurement and control will allow better response to changing gin conditions, including those caused by variation in cultivar. Better machinery design and management can be used to respond to these variations in seed cotton. Improved ginning machinery and better measurements of the cotton being processed will contribute to optimization of the entire ginning system. 1) Refine the design, operation, and management of existing cotton ginning machinery. We will test modifications to existing machinery and new machine designs for the three main functions of ginning machines–seed cotton cleaning, fiber-seed separation, and lint cleaning. We plan to develop machinery with adjustable operating parameters for use in control systems to optimize product value and quality. New management strategies will also be tested. 2) Improve cotton gin processing by improving measurement and use of measurements. Three issues will be addressed under this objective: 1) some important properties are unidentified; 2) no technique exists for measuring certain important properties, particularly in real-time at the gin; and 3) analysis using the current variables results in interactions, which may result from not measuring the correct variables or an incomplete understanding of the processes. First, we will simplify the control problem using cotton from a limited number of known cultivars and growth conditions. Second, we will find measurable traits which will allow adjustments to the ginning process for optimal processing of different cultivars, without knowledge of the cultivar. Finally, a control system using these properties will be developed to maximize fiber value and quality, accounting for variation due to cultivar and growth conditions. 3) Improve automated measurement of relevant properties and control of gin processes for more efficient management, especially related to moisture, fiber quality, and energy use. Currently, many important properties to gin management cannot be measured accurately, or in real-time at the gin. Sensors will be developed to measure these parameters. Advanced statistical techniques will be used to integrate information from many sensors and develop predictive models. The final step will be to develop a control system using these sensors and logic which will result in improved gin management, as demonstrated by improved fiber quality or more efficient use of resources. 4) Optimize the entire ginning system from the seed cotton module to lint, seed, and byproduct use. Dust emissions from cotton gins will be measured, so that regulatory agencies have accurate data. Energy use will be monitored throughout cotton gins. Systems will be designed that can alert ginners to conditions reducing energy efficiency or automatically conserve energy without negatively impacting gin processing. Improved systems will be designed for controlling drying and moisture addition to improve gin efficiency, product storage, and fiber quality.
3. Progress Report
Gins clean seed cotton to remove extraneous plant parts and soil. A survey of commercial cotton gins showed that some gins regularly exceed the currently recommended seed cotton cleaner loading. Equipment was constructed that was capable of processing at rates 3x higher than currently recommended. Tests showed that processing rates significantly higher than recommended could be used without reducing cleaning performance. Testing in a commercial gin at the recommended maximum rate and double that rate showed some loss in cleaning ability at higher rate. Roller ginning produces lint with greater fiber length and less short fiber than saw-ginning with Upland cottons in California and Arizona. A high-speed roller gin stand has been installed along with lint cleaning equipment designed for use with roller gins. The equipment has been tested with Upland cotton grown in the humid Mid-South and analysis has shown an improvement in fiber when using the high-speed roller gins stand line compared to the traditional saw-gin line. Differences in processing for different cotton cultivars have been observed. Because different cotton cultivars respond differently to ginning processes conventional ginning systems do not process all cotton optimally. To quantify these differences the energy and time for ginning a number of genotypes were measured. The energy needed to gin different cotton genotypes was inversely correlated with ginning rate. This relationship supports the concept of developing cultivars which require less energy to process and which could produce savings for the ginning industry. Material flow rate is critical in automated control. A prototype system has been constructed and tested which demonstrated that the system indicates fiber flow rates accurately. Discussions are underway with a Cooperative Research and Development Agreement (CRADA) partner for developing a commercial instrument. Cotton gins use energy in material transport, processing, and drying. Survey data has shown that the energy used per bale produced varies by over 2:1 even for gins of the same size. Initial analysis of energy use in commercial gins shows that less energy per bale is used when the gin stands are kept fully loaded. Power demand in commercial gins when no cotton is being processed was 2/3 of the fully loaded systems. Ginners are encouraged to shut down equipment when not ginning, thereby saving energy and reducing costs. The effect cotton gins have on air quality and issues in measuring and modeling the effect on air quality are being studied at several locations over several years. These samples and data will be analyzed and results shared with relevant regulatory agencies. Moisture content measurement and control in the gin continues to be a problem for stakeholders. Additional efforts have been made to expand the moisture measurement and management efforts, especially in relation to final bale moisture content, and meetings with stakeholders have been undertaken for technology transfer. Additional work in this area is being planned based on stakeholder requests.
1. Seed cotton cleaning at increased throughput. Seed cotton cleaning machines have seen increasing throughput over the years without documentation of the effects of higher loading since rates of up to 8.0 bales/hour/meter (bales/hr/m) were documented in 1972. Surveys have indicated that a significant number of commercial gins exceed 14.7 bales/hr/m seed cotton cleaner loading. Seed cotton cleaning machinery capable of processing cotton at rates of over 23 bales/hr/m was assembled at the Cotton Ginning Research Unit in Stoneville, MS. Rates of 6.6 (the currently recommended maximum rate), 9.8, 13.1, 16.4, and 19.7 bales/hr/m were tested in the recommended sequence of cleaning machinery. Experiments have been conducted with two seasons of cotton. Three cultivars from the first season contained little foreign matter (4.6, 5.2, and 7.2% by weight) and the processing rate had no effect on cleaning performance. Higher processing rates negatively affected cleaning of the other cultivar, which was stripper-harvested and contained 26.4% foreign matter. For the second experiment, cotton with intermediate levels of foreign matter content was tested at two moisture contents. Poorer cleaning efficiency was observed at higher processing rates. No significant seed cotton loss was observed in either test at any processing rate. A processing rate test was also conducted in a commercial gin, comparing processing rates of 6.6 and 13.1 bales/hr/m. Lint leaf grade was improved by 0.4 at the lower rate; however, this difference could be due to improved lint cleaning. The data showed that the processing rates used at most gins did not contribute significantly to increased non-lint content or seed cotton loss with well maintained equipment and verified the acceptability of current practice.
2. High-speed roller cotton gin applied to eastern cotton. Research carried out with upland cotton by ARS in New Mexico and at a few Western commercial gins has shown that the recently available high-speed roller gin stand (HSRG) produced lint with better properties, especially greater fiber length and lower short fiber content, and higher commercial value than the traditional saw-type gin stand. The operation of the HSRG in the more humid mid-south has not been documented. Work with the HSRG at the Cotton Ginning Research Unit in Stoneville, MS, has shown approximately the same improvement in fiber properties as was observed with the upland cotton grown in the more humid eastern U.S. as was observed in the drier west. Certain cultivars have been shown to gin more easily and others with more difficulty when using the HSRG. Ginning at lint moisture contents higher than those used in the drier west has not resulted in any difficulties. A commercial mill has requested bale sized samples of eastern upland cotton ginned with the HSRG and several commercial gins located in the east have expressed interest in producing commercial quantities of the lint. A Trust Agreement is being developed with the mill and other ARS units to expand this work. Use of the HSRG will produce cotton lint which has better fiber length properties making the fiber more desirable by cotton mills benefitting cotton producers in the eastern U.S.
Sui, R., Thomasson, J., Byler, R.K., Boykin Jr, J.C., Barnes, E.M. 2010. Effect of machine-fiber interaction on cotton fiber quality and foreign-matter particle attachment to the fiber. Journal of Cotton Science. 14:145-153.