Abstract
ABSTRACT The process of solid circulation in an internally circulating fluidized bed (ICFB) having two or more chambers can be developed by applying unequal gas velocities in these chambers. Such a process is beneficial to several applications and provides the means for the energy transfer between the chambers in the ICFB. In this paper, a multi-fluid CFD model incorporating the kinetic theory of granular flow is used to simulate the hydrodynamic characteristics of a binary mixture of particles in an ICFB using ANSYS-Fluent software. The mixture is composed of two particles of different sizes but the same densities. The ICFB has two chambers named the reaction chamber (RC) and the heat exchange chamber (HEC), separated by a vertical central baffle. An increase in the RC gas velocity UR at constant HEC gas velocity UH results in an increase in the circulation rate of the binary mixture. The circulation rate of small particles GBs is found to be higher than that of the big particles GBb. Increasing the slot size causes a decrease in the pressure difference between the chambers and consequently decreasing the solid circulation rate in the ICFB. The mixture circulation rate also decreases when the mixture is richer in GBb particles than in GBs.
Highlights
Fluidized bed reactors in their various forms are very popular and commonly used in many industries throughout the world
The results showed that the solid circulation between two chambers in the internally circulating fluidized bed (ICFB) is influenced by the superficial fluidizing velocities of reaction chamber (RC) and heat exchange chamber (HEC), static bed height, gas distributor design and structure of the ICFB
Transfer of particles from the HEC to RC through the slot due to pressure difference between the two chambers can be seen in the figure
Summary
Fluidized bed reactors in their various forms are very popular and commonly used in many industries throughout the world. The ICFB chambers are termed the reaction chamber (RC) or fast bed and the heat exchange chamber (HEC) or slow bed Due to their unique structure, ICFBs possess several advantages over CFBs such as reduced height, compact size, low construction cost and comparatively lower heat loss. Because of these advantages, ICFBs serve many purposes such as in coal combustion and gasification (Kim et al, 1997, Lee et al, 1998), biomass gasification (Xiao et al, 2010), disposal of solid waste (Mukadi et al, 1999a, Mukadi et al, 1999b, Milne et al, 1999), flue gas desulfurization (Chu and Hwang, 2005) and membrane reactors (Boyd et al, 2005). The fluidization of wide size distribution (WSD) particles in an ICFB was found to be better than the conventional fluidized bed along with a considerable minimization in the segregation of the WSD particles due to continuous solid recirculation (Li et al, 2015)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
