Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-III-17GAS PHASE OXIDATION OF FORMALDEHYDE INTO FORMICACID ON A V/Ti CATALYST: 2. DESIGN OF A TUBULAR REACTORBY MATHEMATICAL MODELINGN.V. Vernikovskaya, V.N. Kashkin, I.A. Zolotarskii, A.P. Kagyrmanova,T.V. AndrushkevichBoreskov Institute of Catalysis SB RAS, Novosibirsk 630090, Russia,e-mail: zol@catalysis.nsk.suIntroductionBoreskov Institute of Catalysis has developed a catalytic route of formic acid productionby direct oxidation of formaldehyde by air oxygen in a gas phase. Thus, formic acid can beproduced from methanol, the well established technology of methanol oxidation intoformaldehyde on the oxide catalyst being the first stage:CH 3 OHO2HCHOO2HCOOHThe key component of the technology is the appropriate V/Ti oxide catalyst providinghigh selectivity of formaldehyde oxidation at temperature range 100-130 °C. The goal of thiswork was a choice of catalyst particle shape and sizing of a commercial cooled tubular reactorfor oxidation of formaldehyde into formic acid based on comprehensive mathematicalmodeling of the reactor tube.Mathematical modelA two-dimensional quasihomogeneous model of a catalyst bed incorporating a dusty-gasmodel of a catalyst particle was used. Intrinsic reaction kinetics was studied and established in[1], effective diffusivities being determined from special experiments with full-size catalystpellets. Heat transfer parameters of the model are defined by correlations valid for differentholed particles [2, 3].Optimization procedureFor each catalyst shape, reactor residence time (catalyst volume at fixed capacity) wasminimized under restrictions imposed on formaldehyde conversion, pressure drop, hot spottemperature, hot spot temperature sensitivity and quality catalyst paсking. The last restrictionis evaluated quantitatively according to [4] as a) minimum allowable ratio of reactor tube toparticle diameters and b) allowable ratio of catalyst particle longitudinal and diametricaldimensions. Temperature sensitivity is defined as hot spot temperature rise at increase ofcooling agent temperature by one degree. In some cases constraints can be put on catalystparticle wall thickness due to a strength issue.335