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ARS Home » Plains Area » Las Cruces, New Mexico » Cotton Ginning Research » Research » Publications at this Location » Publication #80884
Title: MODELING SEED COTTON MOISTURE FROM AIR TEMPERATURE DROP AND MASS FLOWS

Author
item GILLUM, MARVIS
item ARMIJO, CARLOS - LAS CRUCES NM

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/10/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Cotton ginning plants do not have an adequate method to determine the moisture content of the cotton as it enters the gin plant. Knowing the moisture content would allow gin plants to properly adjust their drying systems as they condition the cotton for ginning. A simple mathematical model was developed to predict the moisture content of the cotton. The model uses air temperature, air mass flow, and cotton mass flow to account for heat transfers between the conveying air, the cotton, and the environment. An experiment determined that the model does an adequate job of predicting moisture contents between 6 and 20%. The model does not work well at moisture contents below 6%, but gin plants have no reason to dry below this level. The experiment used ordinary equipment to measure flows and temperatures, making it easy for a gin plant to implement the method. Better utilization of a gin plant's drying system improves ginning efficiency (not enough cotton drying causes poor ginning and cleaning, and machinery choke-ups), improves fiber quality (too much drying damages the fiber), and reduces drying fuel costs.

Technical Abstract: A mathematical model was developed to predict seed cotton moisture content during seed cotton conditioning. The model uses air temperature, air mass flow, and seed cotton mass flow to account for the following: heat transfer (sensible heat lost) from the conveying air, heat added to the room, heat added to the seed cotton, heat added to the moisture in the seed dcotton to raise the water temperature, and heat added to vaporize the moisture in the seed cotton. Two seed cotton conditioning rates, two mixpoint temperatures, and two levels of moisture content are used to calibrate the model. The model is simplistic in that it considers seed cotton as a whole; it does not split the seed cotton into the lint and seed components. The model has an acceptable R**2 of 0.80 when regressed against actual seed cotton moisture content. The model does not work well at moisture contents below 6%, but most gin plants have no reason to dry below this level.