Temperature, concentration, and pumping effects on PAM viscosity

Bjorneberg, D.L. (1998) Temperature, concentration, and pumping effects on PAM viscosity. Transactions of the ASAE. 41(6):1651-1655.

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Abstract

As polyacrylamide (PAM) use in irrigated agriculture increases, new methods are being sought to accurately
and automatically apply PAM with irrigation water. PAM is also beginning to be used in sprinkler irrigation. However,
little information is available about flow characteristics of PAM solutions. This study was conducted to investigate
temperature, concentration and pumping effects on viscosity of two agricultural PAM formulations: a dry powder and an
inverse oil emulsion. Flow tests, using solutions prepared from the dry powder PAM, showed that viscosity decreased as
flow rate increased for concentrations greater than 400 ppm. Thus, accurately predicting PAM viscosity at concentrations
greater than 400 ppm is difficult because viscosity varies not only with concentration and temperature, but with flow
conditions. Flow rate changes due to temperature fluctuations, however, should be minimal for the oil emulsion PAM over
typical temperature ranges occurring under field conditions if tubing diameter is greater than 10 mm and tubing length is
less than 1 m, which should be adequate for all surface irrigation applications. The two PAM products tested had similar
viscosity relationships with temperature and concentration. PAM viscosity for solutions with concentrations < 24 ppm
only increased about 5% relative to water for each 10 ppm increase in PAM concentration. Pumping a 2400 ppm PAM
solution just once through a centrifugal pump reduced viscosity 15 to 20%; pumping five times reduced viscosity
approximately 50%. The viscosity reduction is thought to result from breaking or shearing the PAM molecules, reducing
its effectiveness to stabilize the soil surface and reduce soil erosion.

Item Type:	Article
NWISRL Publication Number:	0975
Subjects:	Polyacrylamide (PAM) > Water-soluble PAM (WSPAM) Mass Import - autoclassified (may be erroneous)
Depositing User:	Users 6 not found.
Date Deposited:	20 Nov 2010 21:54
Last Modified:	17 Nov 2016 16:15
Item ID:	706
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/706