Non‐steady‐state catalytic decontamination of waste gases

Abstract

The non-steady-state behaviour of a fixed bed reactor controlled by periodical direction reversal of reactant feed, applied in catalytic oxidation of industrial waste gases, containing organic compounds and carbon monoxide, has been investigated. The effects of the type of oxidized compound, its initial feed concentration, linear gas velocity, inerts-to-catalyst ratio and inerts thermophysical characteristics on the formation of reactor concentration and temperature fields were elucidated. It was shown that autothermal reactor behaviour is guaranteed by concentrations of the oxidized component which ensure an adiabatic temperature increase in excess of 20 "C. Deviations of either flow rate or initial concentration of the oxidized compound do not disturb the operational stability.

Catalytic Combustion of Very Lean Mixtures in a Reverse Flow Reactor Using an Internal Electrical Heater

“…However, they observed that the width of the plateau becomes smaller. In our case with ∆T r < ∆T ad,min the self-adaptative behavior of the RFR reduces the maximum temperature in order to compensate for the heat removed by convection when the cycle period is increased on the other hand, simulations by Sapundzhiev et al (1991) and by Eigenberger and Nieken (1988) agree with the experimental ones of Figure 6. The conversion was 100% up to a cycle period of 800 s, and it reduces to 95% for a period of 1200 s. Finally we can conclude that the presence of the electrical heater will make it more difficult to find the optimum cycle period.…”

“…The applicability of a reverse flow reactor (RFR) for the purification of waste air has been demonstrated by several authors by using both modeling and experimental studies (Matros et al, 1988(Matros et al, , 1993bEigenberger and Nieken, 1988;Chumachenko and Matros, 1990;Sapundzhiev et al, 1991;Nieken et al, 1994a,b;Purwono et al, 1994;Westerterp, 1994, 1996). These works are devoted mainly to analyzing and discussing the influence of the various reaction and reactor parameters, such as the rate constant, activation energy, cycle period, stability and control, gas velocity and properties, adiabatic behavior, methods of cooling or heating part of the bed, ratio of inert solids to catalyst, and other operational considerations.…”

Effect of wall properties on the behavior of bench‐scale reverse flow reactors

“…One of them was VOC abatement, studied afterwards by other authors, such as van de Beld et al . 3, Eigenberger and Nieken,4 and Sapundzhiev et al5 Complete reviews on the RFR technology are available in the bibliography 6, 7…”

Effect of the catalyst properties on the performance of a reverse flow reactor for methane combustion in lean mixtures

“…Similar conclusions were obtained by Vandebeld and Westerterp [19,20], also finding that pressure hardly affects the performance of the process provided that the inlet mass flow is constant and the deep oxidation kinetics of the involved compounds fit well to a first order law. Sapundzhiev et al [21] showed in a simulation study that the maximum temperature of the reactor and its stability increase as the heat capacity of the inert packing increases. They also studied experimentally the catalytic combustion of methane lean mixtures finding a good fitting to a heterogeneous bidimensional model [22], and they proposed and simulated a new RFR type in which there is a heat exchanger in the centre of the catalytic section [23].…”