(240d) A Kinetic Study On Formaldehyde and Acetaldehyde Reactions in Supercritical Water

Over-abundance of glycerin from biodiesel production has led to numerous studies on ways to convert and utilize glycerin.  One technique employed is to decompose glycerin in a supercritical water medium.  This can result in valuable intermediate chemicals or complete gasification of glycerin into syngas.  To effectively use this process, a complete and comprehensive understanding of the reaction pathway and kinetics of the decomposition of glycerin is desired.  Two of the intermediate compounds produced during glycerin decomposition in supercritical water are formaldehyde and acetaldehyde.  This study was carried out to elucidate the kinetics of the various mechanistic reactions of formaldehyde and acetaldehyde in supercritical water.  Experiments were conducted non-catalytically in a continuous, 0.1 L Haynes® 282® alloy reactor at 22.4 MPa.  Temperatures of 500 ˚C to 700 ˚C, feed concentrations of 0.5 mol/L to 2 mol/L, and space times of 30 seconds to 60 seconds were studied to determine the kinetic parameters of the various reactions.