Cotton Ginning

The main product of the cotton plant is long and strong fibers that are used to make yarn for clothing and other textile products. These fibers originate on the surface of cotton seeds growing inside a cotton boll, the fruiting structure of the cotton plant. When cotton is harvested, the fibers are still attached to seeds, so the harvested mass is called seed cotton. Modern cotton harvesters create round “modules” of seed cotton in the field and wrap them in plastic to protect them during storage and transport prior to ginning. The modules are taken to a cotton gin where the fiber is removed from the seed, and any extraneous matter is also removed. The fiber is then compressed into high-density rectangular bales that can be efficiently stored and shipped to spinning mills. Occasionally pieces of plastic from the module wrap or other sources end up in a bale of cotton and cause problems at the mill.

Projects:

 

• Fate and Transport Study on Cotton Contamination at the Gin

  The Cotton Engineering program has been seeking an answer to the following questions. Once a piece of module-wrap plastic is ingested with the seed cotton into the machinery at a cotton gin…

  1. Where do the pieces end up? In the bale? In the trash collection system? Etc.
  2. How long does it take the pieces to get where they’re going?
  3. In what form do the pieces end up? Whole pieces? Ground up pieces? Etc.
  4. What effect do the size and shape of the incoming piece have on all of the above?

• Detection and Removal of Plastic Contamination of Cotton

  The Cotton Engineering program has been seeking to develop methods to detect and potentially remove pieces of plastic in the seed cotton at one or more process locations in the cotton gin.

• High-Moisture Seed Cotton Issues in Harvesting, Transport, Storage, and Ginning

  In some areas of the Cotton Belt, high levels of moisture in harvested seed cotton can present problems.  High moisture can be caused by harvesting when the cotton is damp due to condensation (dew) or precipitation, or it can be cause by storing the cotton in areas where water pools.  A good deal of moisture can be removed from seed cotton during ginning by applying warm air from dryers.  However, cotton that is excessively wet, particularly if the seeds are wet and have become soft, can be very difficult to gin, thus drastically slowing ginning and increasing the per-bale ginning cost.  The Cotton Engineering program is conducting research on the origins and effects of high-moisture seed cotton in order to minimize the problem.

• Plastic Removal at the Module Feeder

  Plastic contamination is estimated to cost the US cotton industry over $100 million per year. The primary source is the plastic used to cover round cotton modules; pieces of this material become wrapped around rotating cylinders in the first machine in the cotton gin. The Cotton Engineering program has been seeking to develop an automated system for removal, which would prevent the creation of smaller pieces as the wrapped plastic rotates and improve safety as workers would no longer have to shutdown equipment and retrieve plastic.

• Modeling of conveying and drying of seed cotton in gins

  Gin dryers are only about 20% efficient, yet proper drying is necessary for optimizing cotton quality and smooth operation of the cotton gin. Numerous designs of dryers have been used and equipment designers and operators have suggested that multiple process parameters may be important, often without strong evidence. The Cotton Engineering Program is developing a validated modeling framework that will enable efficient testing of different designs and varying process parameters to develop systems that optimize energy efficiency and fiber quality.

• Tracking Round Modules and Wrap Damage with RFID

  The rapid adoption of the round module system in the cotton industry provides new opportunities for improved logistics, but has created a major potential source of contamination. While a number of studies have modeled transportation costs of round modules from the field to gin, the costs of staging modules in the field and handling on the gin yard are not known. The Cotton Engineering Program is conducting research on tracking the movement of round modules, which will allow labor and equipment costs for handling to be estimated. Evidence indicates that well-formed modules with intact wrap are not the source of most contamination, so we are capturing images of modules during handling to determine when wrap damage occurs and leads to contamination.