Dynamicmodelling of catalytic three-phase reactors for hydrogenation and oxidation processes

Kinetics of Lab Prepared Manganese Oxide Catalyzed Oxidation of Benzyl Alcohol in the Liquid Phase

“…The rates of heterogeneous catalytic reactions are complex, because adsorption of the reacting species on the surface of the catalyst, reactions between the adsorbed species and desorption of the products take place simultaneously. Basically, the catalytic reactions are described with surface concentrations; however, the effect of surface concentrations on rates of reactions can be eliminated by using simplifying assumptions, such as quasi‐equilibrium and quasi–steady‐state hypotheses . The kinetics of the oxidation of benzyl alcohol in the present case can be expressed as the power rate law,where k is the rate constant and m and n are the reaction orders with respect to benzyl alcohol and oxygen, respectively.…”

Dynamic modelling of catalytic liquid-phase reactions in fixed beds—Kinetics and catalyst deactivation in the recovery of anthraquinones

“…In this work, we used the method of lines because of its easy implementation. In using finite differences, expressions are needed for first and second derivatives (Romanainen, 1997;Salmi et al, 2000).…”

“…The derivatives which originate from plug flow should be described with backward differences, whereas central differences should be used for first and second derivatives originated from diffusion and dispersion (Salmi et al, 2000). For the first derivative (the plug flow term), for instance, the five-point backward difference formula can be used (Schiesser, 1991),…”

“…Recently, dynamic modelling of chemical reactors has gained more and more attention, to describe start-up and shut-down phenomena, transient operation as well as catalyst deactivation (Coselli Vasco de Toledo et al, 2001;Haag et al, 1999;Salmi et al, 2000;Wärnå and Salmi, 1996). Dynamic models are needed to optimize operation cycles of fixed beds, where the catalyst is subject to deactivation and the deactivation effects cannot be decoupled from intrinsic kinetics.…”

Use of Different Numerical Solution Approaches for a Three-Phase Slurry Catalytic Reactor Model

“…The parameters values used an this work are given in Table 1. More details on dynamic modeling of three-phase reactors: Santana (1995), Warma & Salmi (1996), Santana (1999), Lange et al (1999), Julcour et al (1999) and Salmi et al (2000). Operational parameters, and mass and heat transfer coefficients A gfo = 1.5 × 10 -2 kmol/m 3 A lfo = 1.5 × 10 -2 kmol/m 3 B lfo = 2.4 × 10 -3 kmol/m 3 C pg = 14.0 kJ/kg.K C pl = 2.40 kJ/kg.K C pr = 3.40 kJ/kg.K C ps = 0.15 kJ/kg.K D ea = 5.16 × 10 -8 m 2 /s D eb = 9.7 × 10 -8 m 2 /s D t = 0.154 m h s a ls = 400.0 kJ/m 3 .K (K gl ) A a gl = 0.8 s -1 (K ls ) A a ls = 5.6 s -1 (K ls ) B a ls = 3.0 s -1 L = 2.0 m R p = 2 × 10 -5 m T fo = 540 K T ro = 500 K u g = 1.8 m/s u l = 0.008 m/s u r = 3.0 m/s U = 8.0 × 10 -2 kJ/m 2 .s.K ∆H R = -6.67× 10 4 kJ/kmol λ s = 3.47 × 10 -4 kJ/m 3 .s.K Same of the parameters shown in Table 1 are presented by Vasco de Toledo et al (2001), others parameters were generated by correlations given by Ramachandran & Chaudhari (1983), Deckwer (1992), Santana (1999).…”