Seed Cotton and Lint Moisture Addition at a Western Cotton Gin
Authors: Whitelock Derek P , Armijo Carlos B , Delhom Christopher D 
Published: June 2018

Testing was conducted at a western commercial cotton gin to evaluate the effect of humid air moisture addition on fiber quality, bale value, and operating costs; when applied at the gin stand feeder conditioning hopper and battery condenser lint slide. Two tests each with 19 conventional modules of upland cotton were conducted over two consecutive days. The moisture treatments included feeder hopper moisture on or off and lint slide moisture on or off, resulting in four treatment combinations: 1) no moisture added (No Addition), 2) moisture added at the feeder hopper only (Hopper Only), 3) moisture added at the lint slide only (Slide Only), and 4) moisture added at the both the feeder hopper and lint slide moisture (Hopper+Slide). Results showed that seed cotton moisture content at the gin stand was about 0.1 percentage points higher when moisture was added at the feeder hopper and lint moisture content in the bale was about 0.9 percentage points higher when moisture was added at the lint slide. Adding moisture at the feeder hopper resulted in small, but significant (p-value = 0.05), improvements in HVI length [+0.21 mm (0.008 in.)], uniformity (+0.16 percentage points), and strength (+0.25 g/tex), and AFIS length [+0.4 mm (0.016 in.)] and short fiber content (-0.52 percentage points). However, fiber yellowness also increased (+0.12 +b) when moisture was added at the feeder hopper. Adding moisture at the lint slide had very little effect on fiber quality. Moisture addition at either location did not significantly affect spinning performance or yarn quality. Lint produced with moisture added only at the feeder hopper had the highest average value [$1.254/kg (56.88 ¢/lb)] and lint with moisture added only at the lint slide had the lowest value [$1.234/kg (55.98 ¢/lb)]. Bales produced with added moisture were heavier, 9 kg (20 lb) heavier on average for the Hopper+Slide moisture addition than for No Addition. Bales produced using moisture addition not only contained more moisture, but also more lint. This could be due to easier bale pressing, which was supported by measurements which showed that about 2 kW less press power was required to press bales with moisture added at the lint slide. Moisture added at the feeder hopper resulted in the greatest overall increase in value over the value of cotton ginned with no moisture addition, more than $32,000 when extrapolated over 10,000 bales. The moisture addition treatments required more energy to produce bales, mainly due to the additional natural gas required for air humidifying equipment. However, since bales with added moisture contained more dry lint resulting in fewer bales pressed for the same amount of dry lint in bales produced with no moisture addition, savings in bale packaging materials and labor costs made operating the moisture systems slightly less expensive than not, up to about $1400 less for 10,000 bales with the Hopper+Slide moisture addition. Although the results showed little impact on cotton quality by adding moisture, the subtle differences and heavier bales containing more lint could have a significant effect on the value to a producer over an entire cotton crop or to a gin over an entire season. Keywords: Cost benefit analysis, Cotton ginning, Energy, Fiber quality, Humid air, Moisture addition.