Modelling of a fluidized bed carbonator reactor to capture CO2 from a combustion flue gas

Abstract

In recent years several processes incorporating a carbonation-calcination loop in an interconnected fluidized bed reactor have been proposed as a way to capture CO 2 from flue gases. This paper is a first approximation to the modelling of a fluidized bed carbonator reactor. In this reactor the flue gas comes into contact with an active bed composed of particles with very different activities, depending on their residence time in the bed and in the carbonation-calcination loop. The model combines the residence time distribution functions with existing knowledge about sorbent deactivation rates and sorbent reactivity. The fluid dynamics of the solids (CSTR) and gases (PF) in the carbonator are based on simple assumptions. The carbonation rates are modelled defining a characteristic time for the transition between a fast reaction regime to a regime with a zero reaction rate. On the basis of these assumptions the model is able to predict the CO 2 capture efficiency for the flue gas depending on the operating and

The impact of calcium sulfate and inert solids accumulation in post-combustion calcium looping systems

“…Taking into account all previous considerations, the carbon mass balance in the solids phase can be expressed as [36]:…”

“…(1)) is the average of the difference between the CO 2 volume fraction in the carbonator and that in equilibrium conditions, which is obtained through Eq. (8) [36]: ν ν…”

“…The fraction of particles that are active and able to react with CO 2 are those which have been in the carbonator for a shorter time than that required to achieve their maximum carbonate conversion, t* [36]. Therefore, f a is formulated in accordance with the CSTR residence time distribution [36]:…”

“…Mass and energy balances were solved for each configuration using an updated version of the carbonator model proposed by Alonso et al [36]. This model assumes that the carbonator behaves as a continuous stirred tank reactor (CSTR) for the solids, so that the conversion of the particles is based on their residence time distribution, whereas the carbonator performs as a plug flow reactor (PFR) for the gas phase.…”

CaO-based CO2 Capture Technology and Its Application in Power Plants

“…It is therefore necessary to examine the models of those reactors in order to analyze the lime based CO 2 capture system. The first approximation to the modeling of a fluidized bed carbonator reactor has been proposed and the efficiency of CO 2 capture is analyzed (Alonso et al, 2009). The KL fluid bed model (Kunii and Levenspiel, 1990) has been used to interpret the experimental CO 2 concentration profiles measured inside the bed during the fast reaction period in literatures (Abanades et al, 2004;Romano, 2009).…”