Study of the effect of phosphate on the rheological properties of molasses at five different temperatures

aamarpali ratna puri, Guru Nanak Dev University, Amritsar
s kaur, Guru Nanak Dev University, Amritsar

Abstract

Rheological description of non-newtonian solutions like molasses is required in process and flow designing. Presence of phosphate in optimum concentration in cane juice is essential for good clarification and has beneficial effect on sugar crystallization. The Brookfield HBDV III programmable rheometer with small sample adapter was used for the present rheological study. The experiment was performed with five molasses samples having added phosphate 0, 20, 40, 60 and 80ppm at five different temperatures. The apparent viscosity was found to decrease with increase in shear rate as well as with rise in temperature at all the phosphate levels indicating shear thinning or pseudoplastic behavior. A very good correlation coefficient (0.999) and low standard deviation indicated the accuracy. The molasses was thus found to be non-newtonian at lower temperatures in all the samples and newtonian at higher temperatures in the samples having lower phosphate level. Consistency index was fitted to the Arrhenius equation as a function of temperature and activation energy of flow and Arrhenius constant parameters were evaluated. The energy of activation was found to decrease with the addition of phosphate indicating decrease in viscous drag of the solution.