Alessandra Beretta

A Complete Model of Scr Monolith Reactors For the Analysis of Interacting Nox Reduction and So2 Oxidation Reactions

A previous one-dimensional model of the SCR monolith reactor has been extended to include the treatment of the undesired SO 2 oxidation reaction. A redox rate expression has been fitted to data, which accounts for the variable order of SO 2 , the asymptotic zeroth order behavior with respect to O 2 , the inhibiting effects of water and ammonia and the slight promoting effect of NO. The complete model successfully reproduces the interaction between DeNO x and SO 2 oxidation reactions, as evidenced by the match between the experimental and predicted dependences of SO 2 conversion on the NH 3 /NO feed ratio. Applications of the model to catalyst design are investigated. The optimal monolithic SCR catalysts have very thin walls, large fractions of macropores to promote diffusion of NO and NH 3 , but low specific surface areas to prevent SO 2 oxidation. According to a dedicated analysis, under industrial conditions it is not possible to modify the catalyst morphological properties in order to induce an NH 3 excess inside the catalyst to inhibit SO 2 oxidation

Theoretical and experimental study of the interaction between NOx reduction and SO2 oxidation over DeNOx-SCR catalysts

The interaction between NOx reduction and the undesired SO2 oxidation over DeNOx-SCR catalysts is investigated experimentally during catalyst conditioning and by transient and steady-state activity tests, as well as by means of model simulations in order to evaluate possible methods to minimize formation of SO3.

Gaining insight into the kinetics of partial oxidation of light hydrocarbons on Rh, through a multiscale methodology based on advanced experimental and modeling techniques

This chapter updates previous reviews on the catalytic partial oxidation of methane and light hydrocarbons over noble metals; specifically, it focuses on the development of experimental and modeling tools that in recent years allowed to measure with accuracy and formalize the kinetics of the surface process, thus setting the basis for the engineering of short contact time CPO reformers. Such advanced tools include special micro-reactor designs for the kinetic investigation under isothermal conditions, first-principle microkinetic schemes, techniques for the spatially resolved measurement of temperature and concentration profiles inside working adiabatic reactors, detailed reactor models accounting for the role of transport phenomena in structured catalysts as well as that of homogeneous reactions. These contributions pave a multi-scale path, that runs from the fundamentals of surface kinetics to the reactor optimal design.

Effect of morphology of honeycomb SCR catalysts on the reduction of NOx and the oxidation of SO2

We present a systematic study of the influence of morphological properties of monolithic SCR catalysts on NOx reduction and SO 2 oxidation, including optimization of the pore structure with respect to the industrial constraints on both NH 3 slip and SO 3 formation.