On using film boiling to thermally decompose liquid organic chemicals: Application to ethyl acetate as a model compound

Film boiling on a horizontal tube is used to study the thermal decomposition of ethyl acetate. The decomposition process is driven by the high surface temperatures that are typical of the film boiling regime that can promote chemical change of superheated vapors in a low temperature liquid. The decomposition products are carried away from the tube by vapor bubbles formed at the top of the tube that then percolate through the system. For the experiments reported here, the bulk liquid is stagnant, the liquid is slightly subcooled, and bubble transport is entirely by buoyancy. The results show that the primary decomposition products are acetic acid and ethylene in proportions consistent with the accepted unimolecular decomposition pathway for ethyl acetate. While ethylene is a non-condensable product gas, acetic acid is miscible in ethyl acetate and small amounts of it were detected in the bulk liquid after four hours of operation. The resulting binary (ethyl acetate/acetic acid) phase equilibrium behavior of the reactant pool contributed to trace amounts of carbon dioxide and methane being found in the product gas from acetic acid decomposition that had preferentially vaporized