Mitigation of crystallization fouling using projectiles in a single heated tube

Abstract

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.

Fouling of heat exchangers is a prevalent operating drawback in many industries. Efficient chemical inhibitors have predominantly been used for many years to combat deposit formation. Nevertheless new stringent environmental legislations limit their utilization. In the present experimental study, two spherical type projectiles of different sizes and hardness have been used to clean the inner surface of a single heated tube which was subjected to the deposition of calcium sulphate. Projectiles were then injected at different time intervals of injection of every 2, 5, 10, 15, and 30 minutes. The experimental results show that i) the projectiles would expedite initial nucleation of crystals even if they are soft and easy to propel inside the tube and ii) fouling can only be mitigated if the projectiles exert a shear force that its corresponding removal rate is greater than the net rate the deposition.