Marcus Grünewald

Enhancement of carbon dioxide absorption into aqueous methyldiethanolamine using immobilised activators

Blends of ‘activating’ primary or secondary amines (diethanolamine, DEA) with tertiary amines, (methyldiethanolamine, MDEA) are commonly used for the removal of CO2 from gas mixtures. To avoid undesirable side-effects from these activators, such as increased corrosion or higher energy requirements for regeneration, we propose using immobilised primary or secondary amine groups on solid supports. In this manner the activating additives can be localised to those parts of the absorption column where the high absorption rates achieved are truly beneficial and excluded elsewhere. n nThe studies presented were carried out to provide an initial evaluation of the feasibility of this novel concept. Preliminary experiments carried out in a discontinuously operated stirred tank reactor reveal similar enhancement of the CO2 absorption into ‘activated’ MDEA solution, when the soluble DEA additive is replaced by a suspended solid adsorbent, containing the equivalent quantity of immobilised amine groups. Further experiments examined the CO2 absorption in a three phase fluidised bed column. They demonstrated that the immobilised activator can be employed in a continuously operated process too. n nAll experimental results support the basic feasibility of using immobilised primary amines in place of homogeneous additives to enhance CO2 absorption in tertiary amine solutions.

Multifunctionality at particle level — Studies for adsorptive catalysts

In this work, an attempt has been made to demonstrate the relevance of multifunctional catalyst using an adsorptive catalyst as the model system. The Claus process was used as a reference reaction scheme to study the influence of distribution of catalyst and adsorbent functionalities at the particle level on the performance of an adsorptive reactor. The study reveals the existence of distinct regimes that govern the performance of an adsorptive reactor. The regimes determine the choice of the optimal microstructure at any location in the reactor. Though a non-uniform distribution of functionalities is found optimal, the performance of an optimal uniform distribution is nevertheless comparable. Thus the utility of functionality microstructuring may be limited to the micro-integration of functionalities at the particle level. Micro-integration of functionalities is found to be a useful tool to circumvent transport limitations in an adsorptive reactor. Though not explicitly described here, the optimal distribution of functionalities in an adsorptive reactor also involves a non-uniform distribution of functionalities at the reactor level.

Particle-scale heat removal in fixed-bed catalytic reactors: Modelling and optimisation of a desorptive cooling process

Abstract This paper describes the basic principles of desorptive cooling processes and indicates the pertinent design parameters for such systems. Preliminary experimental results will be presented to demonstrate the extension of regenerative cycle times possible. Detailed dynamic simulations yield results which are in good agreement with the measurements. Model modifications to allow for non-uniform fixed-bed structures and an optimisation strategy for varying process parameters over the course of the cycle are discussed. Finally, the various degrees of freedom available in process design will be addressed with emphasis on operational stability, self-regulating behaviour and asymptotic cyclic steady-state operation.

Adsorption in Multistage Fluidized Bed Column

The objective of this paper is parameter studies on the adsorption process in multistage fluidized bed column with sieve plates. Based on experimental studies on the fluid-dynamic behaviour, simulation runs are used to evaluate the potential using multistage fluidized bed systems as adsorption units.