Seed cotton and lint moisture addition at a Western cotton gin

Authors: Whitelock, Derek; Armijo, Carlos; Delhom, Christopher

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2018
Publication Date: 6/19/2018
Citation: Whitelock, D.P., Armijo, C.B., Delhom, C.D. 2018. Seed cotton and lint moisture addition at a Western cotton gin. Applied Engineering in Agriculture. 34(3):623-632. https://doi.org/10.13031/aea.12618.
DOI: https://doi.org/10.13031/aea.12618

Interpretive Summary: Testing was conducted at a commercial cotton gin to evaluate the effect of adding moisture to seed cotton before ginning and to lint before baling on fiber quality, bale value, and operating costs. The moisture content of the seed cotton was increased by 0.10 percentage points and the lint moisture content was increased by about 0.9 percentage points. Adding moisture to the seed cotton before ginning resulted in small, but significant, improvements in cotton length, strength, and uniformity, but the yellowness of the cotton also increased. Adding moisture to the lint before baling had very little effect on quality. Moisture addition at either location did not affect spinning performance or yarn quality. Adding moisture before ginning resulted in the greatest overall increase in cotton value, more than $32,000 when extrapolated over 10,000 bales. Furthermore, adding moisture reduced the energy needed to press bales and allowed for heavier bales. Heavier bales would result in fewer bales pressed over a season and, thus, cost savings in bale packaging materials and labor. Although the results showed little effect on cotton quality by adding moisture, the subtle differences could have a significant impact on the value to a producer over an entire cotton crop or to a gin over an entire season.

Technical Abstract: 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 lint slide battery condenser. 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 addition (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, 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, despite being on average 7.5 kg (16.5 lb) heavier. Moisture added at the feeder hopper resulted in the greatest overall increase in value, 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, 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 could have a significant effect on the value to a producer over an entire cotton crop or to a gin over an entire season.