Elastic suppression of boiling in network fluids: A mechanism for hard-to-boil massecuite

Abstract

Massecuite is a liquid mixture that is boiled to produce raw sugar. When formed from poor-quality sugar cane, massecuite can be difficult to boil, leading to factory shutdowns lasting several weeks. This “hard-to-boil” (HTB) massecuite is rich in long-chained polysaccharides and thus exhibits a rheology that is dominated by elasticity. We examine how the rheology of massecuite affects the onset of boiling by proposing an extension of classical nucleation theory that accounts for the elastic energy of fluids containing a deformable solid network. The elasticity of a fluid is shown to suppress the onset of boiling through an increase in the boiling temperature, which is calculated to be a linear function of the shear modulus. Using experimental data, the model correctly predicts that regular and HTB massecuite should and should not boil under standard operating conditions. By coupling the boiling problem to a heat transfer model, the thermo-rheological properties of HTB massecuite are shown to greatly increase the time it takes to reach the boiling temperature. We propose further experiments that can be used to validate the theoretical results obtained here. © 2018 Elsevier Masson SAS