HEAT TRANSFER IN A PLAIN JACKET OF A PILOT SCALE STIRRED TANK REACTOR

Recent literature on thermal runaway reaction research in vessels, such as that conducted by Rudniak et al. [2011], still assumes a constant jacket temperature. In this investigation, three-dimensional steady state CFD simulations are performed for the plain jacket of a pilot scale vessel, which predict that the jacket temperature can vary by tens of degrees Celsius across different parts of the jacket even in reactors under a third of a metre in diameter, and that the distribution of heat transfer coefficients is strongly dependent on the flow path. The CFD output values are compared with experimental data of temperature measurements and with the use of correlations to predict heat transfer coefficients from the experimental data. The commercial code Ansys CFX Version 15 has been used to simulate the flow of the commercial heat transfer oil "DW-Therm" through a plain jacket of a pilot scale stirred tank reactor that is boiling water inside the vessel, to approximate a constant process temperature. Industrially used correlations for overall heat transfer coefficients overlook large non-uniformity in the distribution of heat transfer coefficients in jackets that use a liquid heat transfer medium. Westerterp and Molga [2006] gathered sources estimating that about 30% to 45% of runaway reaction incidents have been attributed to either inadequate understanding of reaction kinetics and thermodynamics or inadequate temperature control.