Modelling and CFD simulation of a fluidizes bed reactor to capture CO2 by solid sorbents
Molaei, M., Pericleous, K.A. and Patel, M.K. (2012) Modelling and CFD simulation of a fluidizes bed reactor to capture CO2 by solid sorbents. In: Proceedings of the 8th international conference on CFD in the oil & gas, metallurgical and process industries. SINTEF, Norway.Full text not available from this repository.
CO2 capture from combustion exhaust gases by carbonation using a fluidised bed is a possible technological route to reduce carbon dioxide discharge to the atmosphere. Fossil fuels comprise main source of energy for power generation in existing power plants responsible, for 32% of CO2 emitted in the UK. Since most of these emissions are due to single large sources, in situ post-treatment of the combustion flue gas seems to be an efficient means of capture. In this work, CFD modelling has been used to study the efficiency of CO2 capture in a fluidized bed reactor containing a solid sorbent. A Lagrangian/Eulerian scheme has been developed for this purpose, with the particle tracking model used to describe CaO particle trajectories and mass, momentum and energy exchange with the carrier gas, entering the reactor in a typical flue gas composition. A steady-state condition is assumed, with each trajectory representing a parcel of particles of a given mass and diameter. The number of particles entering the fluidised bed is kept constant, and the fluidization velocity is chosen so that particles remain in the reactor. As the carbonation progresses, ‘heavier’ well-reacted particles are collected to the bottom of the reactor. In the case of a non-uniform size distribution, fine particles would escape from the top of the reactor; in order to keep such particles inside, the geometry was modified to reduce the fluidization velocity. CO2 reduction of the order of 37% was achieved in a single pass, with a mass loading of 116% particles to CO2 in gas phase and an effective reaction area of 29 m2/g of CaO.
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