Speaker
Mr
Harish Jagat Pant
(Bhabha Atomic Research Centre, Trombay, Mumbai, India)
Description
Multiphase flow reactors are commonly used in industry. One of the
requirements for the efficient operation of these reactors is to have
intimate contact or mixing between the different phases. Any spatial
nonuniformity of the phases will adversely affect the process
efficiency. Therefore, it is important to characterize the void
fraction and holdup, and their spatial distribution in multiphase flow
reactors. The $\gamma$-ray transmission technique commonly known as
$\gamma$-ray densitometry is one of the commonly used techniques for
measurement of voidage or phases holdup in multiphase flow systems
because of its noninvasive nature and applicability to opaque systems.
In $\gamma$-ray densitometry, a collimated radiation source
(usually $^{137}$Cs) and a scintillation detector are mounted
in a horizontal plane across the diameter of the flow system under
investigation. The narrow mono-energetic beam of the $\gamma$-rays
with an incident intensity passes through the system (walls
and material within the system). A fraction of the incident beam is
attenuated within the system and the transmitted intensity of
the $\gamma$-rays is recorded by the detector connected to a radiation
counting system. Let us consider an industrial process system, i.e.,
gas-solid fluidized bed system and record intensity of transmitted
$\gamma$-rays at three different conditions of operation, i.e., with
empty system (with air), with solids and with two phase flow
(fluidized condition), then the line averaged void fraction of
the fluidized bed is estimated using equations detailed in $[1]$:
The technique was used for estimating voidage/holdup in pilot-scale
two phase flow systems, i.e., fluidized beds and bubble column reactor
to evaluate mixing of the two phases $1,2$. The results of the
studies helped to understand the flow dynamics of the phases and
validate or improve the design of the system.
$[1]$ S. Bhowmick, *et al.*, Ind. Eng. Chem. Res., **54**, \#46, 11653–11660, (2015).\
$[2]$ D. Mandal, *et al.*, Powder Technology, **226**, 91–98 (2012).\
| Country/Organization invited to participate | India |
|---|
Primary author
Mr
Harish Jagat Pant
(Bhabha Atomic Research Centre, Trombay, Mumbai, India)
Co-authors
Jitendra S. Samantray
(Isotope and Radiation Application Division, Bhabha Atomic Research centre,Trombay, Mumbai 400085, India)
V. K. Sharma
(Isotope and Radiation Application Division, Bhabha Atomic Research centre,Trombay, Mumbai 400085, India)
