In recent years, there has been a growing interest in bioreactors, which utilise immobilised enzymes and cells in order to improve the bioprocess productivity. In fact, there are many specific advantages of the immobilised systems in comparison with the more conventional systems, in which the bio-agents are suspended freely (cells) or dissolved in a bulk aqueous medium (enzymes): • high cell de...

Nowadays distillation is recognized as one of the economical and the most trustable separation methods in chemical, petroleum, gas and petrochemical industries. It is almost used as a first and the most applicable choice in separation methods. In this article the effect of inlet downcomer on the hydrodynamics of industrial sieve tray has been elaborated. The study was carried out by using a 3-D...

INTRODUCTION Since almost all industrial scale columns are round, the side downcomers present unique challenges for liquid distribution both to and from the downcomers. Liquid leaving these downcomers needs to spread outwardly, away from the flow path centerline, in order to evenly feed the diverging tray active area. Also, one of the characteristics of side downcomers is that they naturally te...

An external liquid circulation is introduced into a traditional internal loop reactor in order to improve liquid circulation and increase the interface between gas and liquid phases. The effects of superficial gas velocity and external liquid circulation velocity on local and overall gas holdups are explored experimentally and numerically in the loop section of a combined gas-liquid contactor, ...

Plunging liquid jet reactor (PLJR) has gained popularity as a feasible and efficient aerator mixer. However, the measurement of air disentrainment rate (Qads), which affects aeration performance, been overlooked by many researchers. In this work, newly invented Al-Anzi ring (ADR) device was incorporated in CPLJR to experimentally measure Qads its effect on net entrainment rate. Furthermore, new...

In airlift reactors transport phenomena are achieved by pneumatic agitation and circulation occurs in a defined cyclic pattern through a loop. In the present work, the effect of geometrical relations on gas holdup and liquid velocity, and consequently on the gas-liquid mass transfer coefficient, was studied in a 6liter airlift bioreactor with AD/AR = 0.63; AD, downcomer cross-sectional area, an...

ROCOM is a four-loop test facility for the investigation of coolant mixing in the primary circuit of pressurized water reactors. Recently, a new sensor was developed for an improved visualisation and quantification of the coolant mixing in the downcomer. This new sensor spans a dense measuring grid and covers nearly the whole downcomer. In the presented work, special emphasis was given to the c...

The design of advanced nuclear reactors [Generation IV (Gen IV)] involves an array challenging fluid-flow issues that affect its safety and performance. Given Gen designs have improved passive features, the downcomer plays a crucial role in loss-of-power scenarios. Fluid-flow behavior can involve forced to mixed natural convection, characterizing heat transfer for these changing regimes is daun...