Yield in trickle bed reactors with liquid induced pulsing flow.

M. ALEJANDRA AYUDE; JORGE CECHINI; MIRYAN C. CASSANELLO; OSVALDO M. MARTINEZ; PATRICIA M. HAURE

Montréal, Quebec, Canadá

Congreso; 8th World Congress of Chemical Engineering (WCCE8); 2009

École Polytechnique de Montréal, Canadian Society for Chemical Engineering (CSChE), McGill University

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; mso-bidi-font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB; mso-fareast-language:EN-US;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> The effect of slow ON–OFF liquid flow modulation on yield is investigated in the oxidation of aqueous solutions of ethanol using a 0.5% Pd/Al2O3 commercial egg-shell catalyst was investigated in a laboratory trickle bed reactor (TBR) operated at 1 atm and 70˚C. The unsteady state experiments were carried out under the same hydrodynamic conditions (degree of wetting, liquid holdup) during the wet cycle. Therefore, the liquid flow rate used during the ON portion of cycling was kept constant, regardless of the duration of dry and wet cycles. Reference steady state experiments were performed at the same liquid flow rate. According to the results presented here, it was found that cycling always improves the production of acetic acid measured as an average between wet and dry cycle outputs, if the off cycle is longer than 2 min, since the residence time of the intermediates and the average oxygen concentrations inside the pellet during cycling are higher than those attained in continuous operation.   Keywords: Trickle bed reactor, liquid flow modulation, constant bed irrigation, yield, noble metal catalyst