Cotton ginning is becoming increasingly sophisticated — even though gin numbers are steadily declining — as ginners utilize new technologies to reduce labor and operating costs and optimize market value.
“The decline in gin numbers in the United States is far from over,” says Thomas Valco, Office of Technology, USDA Agricultural Research Service at Stoneville, Miss.
“Ginners are looking for every opportunity to improve their bottom line by increasing capacity, volume, and value to the customer,” he said at the summer conference of the Southern Cotton Ginners Association at Lafayette, La.
“Good business management practices, as well as machinery operation procedures, and adoption of new technologies will be critical.”
Among the industry trends he is researching, in cooperation with Bill Norman, National Cotton Ginners Association, Memphis, Tenn., are:
- Drying and cleaning
The move is to lower temperature drying, he says. “Educational work in our gin schools is starting to pay off. We know you can really damage fiber if it's overheated or over-dried, causing short fiber content and a lot of fiber breakage. Ginners have taken this to heart, to keep temperatures lower in the dryer and try to process cotton at the optimum rate.
“We're also increasing the air-to-cotton ratio and using one stage of drying to accomplish this. In the cleaning operations, an increased number of cylinder cleaners and increased airflow in those cleaners help to remove trash. The whole key is to do as much cleaning as possible in the seed cotton stage, before the gin stand, so less saw-type cleaning is used and we don't damage fibers in the ginning process.”
- Lint cleaning
“To improve fiber quality, a lot of gins now are pulling out the second stage and only have a single stage of lint cleaning,” Valco says. They also are increasing use of airjet lint cleaners, which can remove big trash particles as well as seed that get through the gin rails. This can help clean up the cotton without doing any damage to the fiber.
“A lot of ginners are looking at Lummus' Sentinel lint cleaner that eliminates the need for batt forming feed works that can cause fiber damage. Others are utilizing the Continental LouverMax lint cleaning system that adjusts the number of grid bars to improve turnout.
“The whole key is to reduce fiber damage, reduce fiber waste, and to improve cleaning efficiency. A main consideration is fiber waste — we know we can always clean up cotton, but the question is how much good cotton do we throw away in that cleaning process?”
Current ARS research, Valco says, is focusing on improving cleaning efficiency, reducing lint loss, and reducing fiber damage.”
- Moisture restoration
“This has been one of the hottest topics in ginning circles, and one we need to continue to focus on. Ginners need to make sure equipment is working at peak performance.
“The National Cotton Council's Cotton Quality Task Force has recommended that we not exceed 7.5 moisture in stored bales. Cotton bales stored at a higher moisture content have potential for degradation of color and problems at the textile mills.”
Moisture restoration prior to the bale press can increase press capacity and reduce hydraulic press pressure and bale tie breakage, he notes. “Research has shown that the addition of moisture prior to the gin stand or reducing seed cotton drying can reduce fiber damage and improve capacity during ginning.”
Valco says about 75 percent of the gins have some type of moisture restoration system. About 80 percent of the gins are using moist air-type systems, while about 20 percent use direct spray or a combination of direct spray and humid air.
“This is a good thing for the gins, and very much needed in improving gin efficiency — we just need to make sure not to overdo the moisture addition.”
Moisture measurement systems are key to being able to manage moisture addition, he notes. About 25 percent of gins have some sort of automated measurement system.
“We've done some excellent research showing if we can maintain moisture somewhere between 6 percent and 7 percent at the gin stand, we can improve fiber quality. There's less fiber breakage, which increases staple length down the line. About 10 percent of gins are adding moisture back prior to the gin stands.”
- Baling systems
“This is a key area most gins are looking at,” Valco says. “This is where a great deal of the labor is, most of their manpower costs. Automated bale-tying and bale-handling systems are coming more into play.”
He estimates 10 percent to 15 percent of gins have fully automated bale tying and handling systems, allowing for increased press speed and greater safety.
New bagging and bale ties are also being used. “Many of these choices are driven by the end user.”
- Gin process control
“We're seeing more gins utilizing this technology in several different ways,” Valco says. “Identification of pre- and post-fiber quality attributes helps ginners to make informed decisions on equipment processing and operation.”
The Uster Intelligin system senses color, trash, and moisture content and uses that information to automatically control certain ginning operations such as dryer temperatures, stick machines, lint cleaners, and moisture restoration. The Schaffner IsoTester (Gin Wizard) measures fiber properties from the bale sample to provide the ginner with timely data to modify gin processing.
“These technologies have been a catalyst in educating ginners about the effects of gin operation and moisture management on fiber quality,” Valco says.
“In the future, additional fiber quality measurements will be added to these systems to improve not only the management of the ginning process, but to improve the linkage between producers and the textile mills.”
Area gins are moving into this area pretty dramatically, Valco says. The percentage of cottonseed directly fed to livestock has increased from 15 percent in 1980 to about 60 percent in 2002.
“Gins, particularly in new production regions, have increased cottonseed storage facilities to capitalize on this marketing opportunity. Certain value-added processes, such as EasiFlo cottonseed, a starch-coated cottonseed for the dairy industry, may help to open new markets and value for cotton seed.”
A lot of gins are looking at composting gin trash as another opportunity to add value to products and increase the gin's profitability, he says.
A variety of electronic systems are helping gins to more quickly and widely process and transmit information to improve handling and marketing of raw cotton, Valco notes.
“Permanent bale identification keeps fiber and processing information constant throughout the life of the bale. The industry has quickly adopted electronic warehouse receipts, now used by about 90 percent of gins. About 55 percent of gins use Internet-based data retrieval for classing data. This fast data availability helps ginners to identify problems with equipment, either in harvesting or ginning. Although it's not current enough to manage gin operation, it can help provide information valuable to the ginner and/or producer on a timely basis.”
Gins are offering these added value services to expanding marketing and increase revenues, Valco says. “As gin sizes are increasing in size, with a greater number of bales, and a greater quantity of byproducts, these types of activities are showing more economic value.
“Gins are looking for every opportunity to improve the bottom line. They're going to be increasing capacity, increasing volume and value, and reducing labor and operational costs, and providing additional services such as byproduct utilization.”