Location: Cotton Ginning Research
2020 Annual Report
Objectives
1: Determine the expected impact of new cultivars, agronomic practices, and harvesting/storage practices on profitability and risks in ginning of Western and long-staple cotton in collaboration with private-sector partners, ARS-SRRC-CSQ, and other ARS laboratories.
1A: Improve or enhance cotton fiber ginnability, textile utility, and cottonseed end use value of new germplasm releases of both Upland and Pima cottons.
1B: Reduce fiber damage during harvesting.
1C: Improve and reduce environmental risk of cotton harvest preparation.
2: Enable, from a technological standpoint, new commercial technologies, methods and processes to (1) improve process efficiencies, (2) reduce uncertainties and risk, and (3) increase end-product and co-product value in the ginning of Western and other long-staple cottons.
2A: Improve seed-cotton drying and foreign matter extraction.
2B: Develop improved saw ginning technologies to increase efficiency and productivity, and enhance fiber quality.
2C: Enhance high speed roller-ginning technologies to increase capacity and improve textile processing efficiency and yarn quality.
2D: Enhance understanding and knowledge of ginning techniques and processes for better decision making tools at the gin and textile mill.
2E: Improve foreign matter extraction and fiber quality of ginned lint.
2F: Develop methods and systems to reduce energy consumption during ginning.
2G: Assist the ginning industry in complying with regulatory standards.
3: Enable the commercial processing of cotton companion crops, such as chile peppers and tree nuts.
3A: Assist tree nut industries in improving process efficiency and reducing environmental risk.
3B: Optimize field machinery for chile harvest mechanization.
Approach
To address critical production, processing and regulatory compliance issues pertaining to Western irrigated cottons and companion crops, this project focuses on three main research areas. The first area advances knowledge of and improves cotton cultivars and production and harvesting practices by 1) collaborating with cotton breeders to determine the ginned fiber quality, textile processing characteristics, and cottonseed quality of newly developed cotton cultivars; 2) investigating cotton picker spindle designs to reduce quality degradation during harvesting; and 3) developing a technology to thermally treat cotton plant stalks for whole-plant desiccation and defoliation. The second improves processing, reduces risk, and increases value by 1) building on earlier work to advance the use of microwave energy to effectively dry seed cotton; 2) improving a device developed to accurately measure seed cotton moisture content for better system management; 3) developing an infrared based sensor to detect plastics contamination in seed cotton at the gin and an electrostatic based device to separate plastics from seed cotton by exploiting static charge affinity differences; 4) evaluating current and, then, developing improved gin saw designs that maintain capacity and reduce fiber damage; 5) cooperating with industry partners in further evaluating and refining a prototype seed cotton reclaimer and lint cleaner feed works capable of processing seed cotton carryover and ginned lint from high speed roller gin stands; 6) evaluating roller ginned upland cotton textile utilization without combing to reduce processing cost; 7) studying in depth the cost of roller ginning upland cottons; 8) exploring improvements in lint cleaner saw wire configuration and grid bar design, and developing new air knife and rotary brush technologies to reduce seed coat fragments in ginned lint; 9) developing continuous air system monitoring and control systems and performing cyclone flow sensitivity analyses to reduce gin energy consumption; and 10) updating particulate emission factors, evaluating regulatory dispersion models, documenting federal reference method particulate samplers for more equitable industry regulation. The third area enhances the viability of cotton companion crops by 1) modifying current walnut drying technologies to reduce energy usage and drying time; 2) building on previous testing and utilizing an experimental approach to improve a retrofit particulate abatement technology for mobile agricultural equipment; and 3) optimizing a prototype to mechanize succulent chili harvest.
Progress Report
This is the final report for project 3050-41000-009-00D, which terminated and was replaced by project 3050-41000-010-00-D in April 2020. To address the three main objectives, progress over the five years of the project focused on cotton production, ginning, textile processing, regulatory issues, and companion crop processing.
Objective 1- The ARS laboratory in Las Cruces, New Mexico, cooperated with Western cotton breeders including Texas AgriLife Extension and New Mexico State University (NMSU) cotton breeding program. This lab provided gin expertise and ginned experimental cottons to produce pure seed for future planting and fiber samples for quality analyses.
Objective 2- Techniques to detect plastic contamination in seed cotton at the cotton gin using near-infrared and infrared spectroscopy, single emitter and detector systems, light-emitting diode/photodiode sensors, and hyperspectral imaging were investigated. ARS researchers in Lubbock, Texas, were enlisted to help investigate low-cost visible-color imaging to detect plastics in cotton. An 85% effective, colored-plastic contamination detection/ejection system resulted from the partnership. The technology was transferred to an industry partner who is working with a U.S. cotton gin machinery manufacturer to produce and sell the complete systems.
Difference in melting point was investigated to separate contaminating plastic from seed cotton. A prototype with a heated-rotating metal cylinder was developed and experiments confirmed that plastic film melted and adhered to the metal surface and was removed from seed cotton if at least 50% of the film was exposed to the metal. A multi-cylinder prototype with continuous seed-cotton flow was designed and fabrication started.
A cotton plastic contamination cleaner produced by a Chinese gin machinery company was purchased by industry and assembled for testing. Initial tests showed that pieces of lightweight round module wrap (RMW) and shopping bags were removed from cotton at a rate within the range of the manufacturer’s claims, but thicker heavy-weight RMW was not effectively removed. Increasing airflow to the cleaner increased plastic capture, but also increased the amount of seed cotton captured with the plastic to unacceptable levels. A fully replicated test to establish the machine’s extraction performance with plastics typically encountered at U.S. gins was designed.
Cryogenically treated cotton gin saws were tested at a commercial cotton gin. After two seasons, untreated saws became worn and were replaced, but the treated saws continued to function properly into the third season. There were no fiber quality differences between treated and untreated saws. The first year of a cooperative project to study gin saw wear and power consumption in response to saw thickness and cryogenic treatment was conducted at a commercial gin facility in 2019. Saw weight, thickness, tooth area, and damaged tooth count were measured to quantify wear. Material properties and microstructure changes due to cryogenic treatment that may explain results are being measured and analyzed.
Experimental high-capacity reclaimers for the growing high-speed roller-ginning industry were developed. The experimental reclaimers had less seed-cotton loss but had more seed loss than a conventional reclaimer. The conventional reclaimer performed better when processing Pima cotton, while an experimental reclaimer based on a current cotton gin machine performed better when processing Upland cotton. Further studies utilizing the experimental reclaimers in series for improved performance were planned.
Current practices used by ARS laboratories to determine cotton moisture content were evaluated in a cooperative study. The research revealed differences between historic and present methodologies, documented the reduced variability and increased statistical power of current practices, revealed a systemic difference that should be considered when comparing results from previous research, and resulted in recommendations for minimum number of samples needed to help conserve ARS resources in the future.
Upland cultivars were processed on saw ginning and high-speed roller ginning equipment and then textile processed to better understand roller-ginned cotton textile utility. The roller ginned cottons produced higher quality yarns in a more efficient manner than cottons produced by saw ginning. The roller-ginned cottons could be processed at higher rates into finer count yarns without a loss of quality. The potential economic benefits of processing high-speed roller ginned upland cotton in a textile mill were explored.
A study was initiated to determine the ginning costs of saw and roller ginneries and the potential economic impact of high-speed roller ginning technology in the Far West. Three years of data were collected and analyzed, but a more comprehensive investigation was needed. An agreement was established with the NMSU Agricultural Economics Department to help develop a survey to collect economic and engineering information from participating ginneries, determine ginning costs, and develop a model to compare the costs and benefits of ginning Upland and Pima cotton using different ginning technologies.
Studies investigating lint cleaning methods to improve fiber quality were conducted. Tests of an experimental high-speed feed condenser that may reduce foreign matter in roller-ginned lint showed that a saw in the condenser was recirculating lint and needed to be replaced by a full-face brush. Trials on an auxiliary air knife working with a grid bar on a saw-type cleaning cylinder showed that the air knife has the potential to remove seed coat fragments (SCF) from ginned lint, but an understanding of how air exiting the knife is distributed along the grid bar is needed. In another effort to reduce SCF, a saw-type lint cleaner was upgraded with a new doffing brush and solid-state controls, and specifications were developed to rewrap the cleaning cylinder with alternative style saw teeth. Per industry request, lint cleaning investigations were expanded to improve fiber length uniformity index. Non-conventional lint cleaner technologies were tested at ginneries in New Mexico, Mississippi, and Georgia using diverse cultivars from across the Cotton Belt. Ginned lint was sent to the ARS Lab in New Orleans, Louisiana for spinning trials. Initial results showed that a technology that eliminates the conventional feed mechanism by coupling the gin stand and lint cleaner to each other and another method that places fiber onto the cleaning saw cylinder in the same direction the cylinder rotates have potential to preserve fiber length and improve length uniformity.
Drying systems in 26 commercial cotton gins across the U.S. were audited over 3 years to identify operating strategies, equipment, and facility designs that resulted in more efficient use of natural gas and propane fuels. Results showed gin operators can save energy by avoiding unnecessary drying, minimizing the volume of conveying air, and operating the gin at its maximum processing rate while avoiding down time. Growers can contribute to more economical operation by harvesting cotton when it’s dry and storing modules, so they don’t get wet.
Two-hundred sixty-four cotton gin particulate matter (PM) emissions sampling reports from a previous project were updated and submitted to the Environmental Protection Agency (EPA) for quality rating and incorporation into EPA’s Compilation of Emission Factors. Comments were received from EPA. The reports are being revised for resubmission and further review.
In cooperative research with the University of Maryland and the ARS research facility in Beltsville, Maryland, the American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) was evaluated using data from a previous cotton gin PM sampling project. Correlations were revealed that will aid in developing and evaluating dispersion models for low-level sources. AERMOD overestimated pollutant concentrations by factors ranging from 7 to 65 depending on the particulate size. A correction factor was developed that improved the predictive accuracy of AERMOD and was recommended for regulatory and practical use. Plans were also formulated to investigate errors associated with federal reference method PM10 and PM2.5 stack and ambient sampling methodologies utilizing data from cotton gin, cattle feed yard, and poultry house PM sampling projects.
Objective 3- Interior dust was collected from almond huller plants in California and subjected to combustibility screening tests. This testing indicated that the almond huller dust should not be considered combustible and therefore not an explosible hazard. The results were promptly reported to industry to aid the industry in keeping almond huller dusts from being classed as combustible.
To help tree nut industries improve drying and achieve higher processing rates, new collaborations were formed with ARS scientists in Albany, California, University of California, Davis faculty, tree nut processors’ associations, and a tree nut processing machinery manufacturer. An extensive literature review of walnut drying was completed, a project to gain understanding of moisture kinetics within the walnut that limit drying rate was planned, and energy audits at walnut drying and almond hulling facilities in California were planned.
This research laboratory cooperated on a project with NMSU that selected improved chile pepper cultivars and production practices based on machine harvest yields. Our staff modified a commercial harvester to be more compatible with domestic cultivars and production practices; designed experiments; and helped with field tests and lab analyses. These efforts helped result in chile pepper cultivars more suited for mechanized harvesting and guidance for growers on target plant density.
Accomplishments
1. Maintaining contamination-free U.S. cotton. This is a story of innovation, cooperation, and achievement. Plastic contamination is the most pressing issue for the U.S. cotton industry today. Due to this problem, U.S. cotton has lost the 7 cents per pound premium it brought on international cotton markets. ARS scientists from Las Cruces, New Mexico, collaborated with other ARS and university researchers to conduct pioneering work on several single-detector and spectral imaging techniques that used ultraviolet, visible, and infrared light to differentiate plastic contaminants from seed cotton at the cotton gin. The efforts were largely successful, showing that colored-plastics could be detected in seed cotton with visible-color reflectance, white or transparent plastics required near-infrared or infrared light for detection, and ultraviolet light differentiated grease from cotton. However, the single detector-based systems were of limited use in the cotton gin setting and the infrared techniques would be cost prohibitive. Fortunately, ARS researchers in Lubbock, Texas, were conducting simultaneous work on visible-color imaging to detect plastics in cotton fields. This led to a partnership that resulted in a 90% effective, low-cost, prototype colored-plastic contamination detection and ejection system. The Lubbock researchers further improved the prototype and ruggedized it for the harsh environments at cotton gins. The technology was transferred to an industry partner who is working with a U.S. cotton gin machinery company to sell and service the complete systems. This development has the potential to help U.S. cotton reclaim its “contamination-free” reputation and regain its premium for millions of export bales. Each penny regained means about $75M back to U.S. cotton producers.
Review Publications
Whitelock, D.P., Buser, M.D., Armijo, C.B., Hughs, S.E. 2019. The impact of historical gin stand technologies on cotton fiber and seed quality. Applied Engineering in Agriculture. 35(5):775-785. https://doi.org/10.13031/aea.12751.
Armijo, C.B., Whitelock, D.P., Funk, P.A., Thomas, J. 2020. Evaluating alternative seed-cotton reclaimers for high-speed ginning. Applied Engineering in Agriculture. 36(3):245-256. https://doi.org/10.13031/aea.13704.
Funk, P.A., Hardin Iv, R.G., Terrazas, A.A., Yeater, K.M. 2020. Cotton gin fuel use patterns. Transactions of the ASABE. 63(3):645-653. https://doi.org/10.13031.
Whitelock, D.P., Buser, M., Holt, G.A., Hardin IV, R.G., Green, K., Fabian, J.C., McCook, D. 2019. Cotton gin pneumatic conveying systems. Journal of Cotton Science. 23:182-217.
Wenbin, J., Whitelock, D.P., Hughs, S.E., Rayson, G. 2018. Low-resolution mid-infrared reflection analysis for discernment of contaminants in seed cotton. International Journal of Analytical and Bioanalytical Methods. 1:1-13.
Hughs, S.E., Holt, G.A., Armijo, C.B., Whitelock, D.P., Valco, T.D. 2020. Development of the cotton gin. Journal of Cotton Science. 24:34-43.
