standardized settling cell design
David Leleu, Andreas Pfennig [email protected]
Products, Environment, and Processes (PEPs) Department of Chemical Engineering
Université de Liège
agenda
introduction
Henschke settling cell shaking settling cell coalescence model results
summary
large gravity settlers in the industry
ERICAA project
partners:
Bayer Technology Services, Franken Filtertechnik, SOPAT, Normag, LANXESS Deutchland, Raschig, INEOS Phenol, Linde, Covestro,
ERICAA project: our goals
definition of an appropriate coalescence
model
design and validate an optimized
standardized lab-scale settling experiment
Henschke settling cell engine double-wall glass vessel 2 counter-rotating shafts second vessel for internals
settling experiment
repeated 3 times
settling time criteria movie used to define
initial d32 and rs*
experiments parameters evaluation 0 4 8 12 16 20 24 28 32 36 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 h e ig h t (m ) time (s)
shaking settling cell 8 light engine bottles linear ball bearing crank
coalescence model: theory 10 coalescence frequency ω coalescence efficiency λ collision frequency h 𝜔 = 𝜆 ℎ = h exp(− 𝑡𝑐𝑜𝑎𝑙𝑒𝑠𝑐𝑒𝑛𝑐𝑒 𝑡𝑐𝑜𝑛𝑡𝑎𝑐𝑡 ) contact time
coalescence time fluid dynamics
fluid dynamics system properties
Surface of the settling cell
coalescence model: collision frequency 𝑐𝑜𝑙𝑙𝑖𝑠𝑖𝑜𝑛 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 = ൗ 𝐴𝑟𝑒𝑎𝑐𝑜𝑙𝑙𝑖𝑠𝑖𝑜𝑛 𝐴𝑟𝑒𝑎𝑐𝑒𝑙𝑙 𝑡𝑐𝑜𝑙𝑙𝑖𝑠𝑖𝑜𝑛 d1 d1+d2 d2 d2
coalescence model: contact time
12
assumptions:
big drop contour
followed by the small drop during the
sedimentation
detachment angle =
opposite of the collision angle
αcollision
contact time for different collision angle 0.0 0.2 0.4 0.6 0.8 0 /8 /4 3/8 /2 c ollis ion an gle in rad contact time in s 0.2503
contact time with a drop of 1 mm 14 0.0 0.2 0.4 0.6 0.8 1.0 0.01 0.02 0.04 0.06 0.08 0.1 0.2 0.3 c o n ta c t ti m e i n s
summary
different settling cell devices with different
characterization tools
design of a unified standardized cell development of a coalescence model
