I. Harwigsson et M. Hellsten, ENVIRONMENTALLY ACCEPTABLE DRAG-REDUCING SURFACTANTS FOR DISTRICT-HEATING AND COOLING, Journal of the American Oil Chemists' Society, 73(7), 1996, pp. 921-928
The aim of this work was to find drag-reducing surfactants for both di
strict heating and cooling that are environmentally more acceptable th
an the organic salts of quaternary ammonium compounds that so far have
dominated this application. Vortex inhibition of test solutions in gl
ass beakers has been used to screen a large number of surfactant mixtu
res, various electrolytes, and temperatures. For the most interesting
products, the pressure drop in a test loop was measured at various flo
w rates and temperatures. N-cetyl sarcosinate and N-stearyl betaine, t
he latter together with Na-dodecylbenzene sulfonate, give good drag re
duction (DR) properties at 65-100 and 45-85 degrees C, respectively. T
he sarcosinate is sensitive to pH changes, whereas the betaine-sulfona
te complex is more robust. Ethoxylates of oleic acid monoethanolamide
show good DR properties at 0-25 degrees C. At an increased salt concen
tration, a mixture of this surfactant with an ethoxylated oleyl alcoho
l worked well. At a still higher salt concentration, e.g., sea water,
a combination of N-cetyl betaine and alkylbenzene sulfonate showed DR.