چكيده به لاتين
Abstract:
Gas-solid fluidized bed is one of the most important types of industrial
facilities, particularly the reactors of this type due to significant mass and heat
transfer capability, have found a key role in process industries. The current
research in the area of fluidized beds aims to enhance the hydrodynamics, mass
transfer and reaction occurring in the bed by reducing the bubble size. In recent
years, numerous researchers have applied different methods to reduce the
bubble size in order to improve hydrodynamics, mass transfer and reaction
performance of fluidized beds. The current research employs a novel approach
which is based on different injection patterns in gas distributer so as to find the
most suitable injection pattern for the bed performance. In this regard, a 3D
cylindrical solid gas fluidized bed taking into the account mass transfer and
reaction is constructed and simulated using Discrete Bubble Model (DBM).
Different injection patterns are generated using a mathematical function i.e.
Beta random function and three distribution pattern, namely linear Random
Injection Pattern (LRIP), Circumference Oriented Injection Pattern (CiOIP) and
Central Oriented Injection Pattern (CeOIP) which are inspired by the idea of
different bubble density in distributer interface are applied and effect of
different parameters such as bubble diameter, bed height, reaction rate constant,
bubble coalescence, inlet gas velocity, etc. on reactant concentration change are
investigated. The simulation results are verified by laboratory data reported in
the literature which satisfactorily comply with each other. Considering three
aforementioned injection patterns, it can be suggested that Central Oriented
Injection Pattern (CeOIP) is the most suitable injection pattern since it leads to
bubbles with minimum average diameter on the top of the bed and it also
minimizes bubble coalescence inside the bed. This result is noteworthy since it
shows that bed performance can be enhanced by only improving the distributor
omitting the need to spend extra energy, increase the pressure drop or
employing degrading internal equipment.
Keywords: Gas-solid fluidized bed, injection pattern, discrete bubble model,
mass transfer, reaction
