“Influencia de la dispersión axial en reactores no catalíticos de transesterificación operando en condiciones supercríticas”

M. BUSTO; S.A. D’IPPOLITO; M.E. ITURRIA; J.C. YORI; C.L. PIECK; J.M. GRAU; C.R. VERA

Gramado, Brasil

Simposio; XX Simposio Ibero Americano de Catalisis; 2006

Sociedad Brasilera de Catálisis

Transesterification of fats and oils by methanol is known to proceed by a three-step consecutive reaction mechanism in which the formation of the diglyceride is the rate-limiting step. At low conversion values (< 35%) the system has mass transfer limitations due to the immiscibility of the oil-methanol system. Non-catalytic transesterification in supercritical methanol overcomes this problem by forming a one phase reacting system. The implementation of this reaction mode in continuous tubular reactor needs for the evaluation of the effect of the backmixing that appears when methanol acquires a gas-like mobility in the supercritical state (³ 250 °C). Such a study was performed here and it was found that supercritical transesterification reactors must be operated at axial Péclet number equal or higher than 1000 in order to limit backmixing to a minimum and achieve batch-like conversions at residence times of 1 hour or less. High conversion values in perfectly mixed reactors can only be obtained by working at inconveniently higher temperatures (T ³ 300 °C) and methanol:oil ratios.fication in supercritical methanol overcomes this problem by forming a one phase reacting system. The implementation of this reaction mode in continuous tubular reactor needs for the evaluation of the effect of the backmixing that appears when methanol acquires a gas-like mobility in the supercritical state (³ 250 °C). Such a study was performed here and it was found that supercritical transesterification reactors must be operated at axial Péclet number equal or higher than 1000 in order to limit backmixing to a minimum and achieve batch-like conversions at residence times of 1 hour or less. High conversion values in perfectly mixed reactors can only be obtained by working at inconveniently higher temperatures (T ³ 300 °C) and methanol:oil ratios.