The objective of the present study is to characterize the catalyst wetting efficiency and investigate the importance of static & dynamic contact angles in liquid drop spreading and dynamics. The experimental techniques for Goniometer setup and digital image analysis tool (drop analysis) for data extraction and calculation is carried out. Experiments were performed on commonly used industrial catalyst pellets of glass and alumina available in different geometries or shape with liquids of varying viscosity surface tension.

Bubble column reactors, with and without suspended solids and in many configurations, are frequently applied in industry for various chemical processes. Industrial bubble columns are often operated at high temperatures and at elevated pressures. Despite this fact, considerable effort has been made to understand the design and scale-up of these reactors at ambient conditions, and it was generally believed that experimental results obtained at atmospheric conditions are suitable for the design and scale-up of bubble columns at high pressures. The aim of the present proposal is to study in depth the gas holdup structure and mixing characteristics over a wide range of operating conditions and gas-Iiquid system properties, specifically, in organic liquids at elevated temperature and pressure.

Biphasic liquid systems are frequently encountered in a variety of processes such as the production of pharmaceuticals and specialty, chemicals, high value-added petrochemicals (olefin hydroformylation) and enzymatic reactions. They are 'also a feature of new process intensification technologies, for example, in phase transfer catalysis and reaction-separation modules which permit improved material recycle and energy consumption. Although there is a voluminous literature on the design of multiphase bubble column reactors (BCRs) for operations involving a single liquid phase, there is practically no design correlation for the biphasic liquid situation. In order to understand the interplay between transport steps and the reaction kinetics in the determination of optimum process variables a 2-year project is proposed to investigate the hydrodynamic characteristics of biphasic liquid systems and the associated quantitative relationships to mass transfer processes across gas-liquid and liquid- liquid interfaces. Dr. A.A. Adesina visited IITD in November 2003 for one month to start the project.

Studies on spreading, surface treatments and spreading rates were carried out. Control of droplet surface area to increase or decrease evaporation, optimal wetting of heat exchanger were taken into consideration.

In this project attempt has been made to study the gas-liquid-liquid system in a bubble column. The different possible pathways of mass transfer from the gas phase to the continuous liquid phase in the presence of immiscible organic dispersed liquid phase has been studied. It is interesting that some organic liquids (n-decane, dodecane and n- heptane) show mass transfer enhancement, where toluene, anisole and 2-ethyl-l-hexanol hinder mass transfer compared to air-water system.

An attempt has been made to predict gas hold up and volumetric mass transfer coefficient as a fraction of physical properties of gas a11d liquids and operating conditions. A correlation has been developed for both gas hold up and volumetric mass transfer coefficient in bubble column operating at high pressure which predicts the literature values with in 20 %.

Monoglycerides are used in many industries such as phannaceutical and food industries. In food industries monoglycerides are used as emulsifying agents to lower the surface tension between two phases and thus stabilize the products against separation of phases. The transesterification of tatty acid methyl esters with glycerol using homogeneous catalyst was studied. The aim was to study the influence of the specific interfacial area and of pressure on the rate of reaction in a liquid-liquid two phase system. A kinetic model for this reaction was developed. A joint publication has been submitted to Catalyst Today based on this research cooperation (2003).

Motionless mixers now play a well-established role in process mixing. Today's technology also allow static mixer to perform a variety additional unit operations, such as absorption, scrubbing, extraction and reaction enhancement. Processes that require high mixing efficiency, controlled shear and plug flow are excellent candidates for motionless mixing. In motionless mixers, homogenization is attained by means of motionless elements by using the flow energy of the fluid.

A new class of Static Mixers has been developed which are intended to homogenize feed streams subject to temporal variation in concentration and temperature. The general design approximates the axial mixing performance of a CSTR without need for moving parts.A joint publication has appeared based on this research cooperation, Trans. I. Chem. Engrs. Part A (London) (2002).

Paper-yellowing inhibitors are polymers like materials that are claimed to be use in inhibiting the yellowing of documents and books over long period of time. The aim of this research is to study the mechanical properties and delivery of these inhibitors to the raw sheet of paper.

Trickle-bed reactors, which are catalytic randomly, packed fixed-bed vertical tubular columns contacted by cocurrent downward gas-liquid flows, host a variety of gas-liquid -solid catalytic reactions especially in the petroleum and petrochemical industries. The aim of this project is to develop a representational flow structure and a detailed residence time distribution (RTD) model which can describe the mass transfer and the backmixing of the liquid flow in a porous particle containing trickle-bed operated under partially and fully wetted conditions.

A motionless mixer is no moving part, duct like mixing device which, by redistributing the fluid across the flow channel, rearranges temperature and compositional distributions and narrows the residence time distributions. Such devices are usually effective in eliminating severe temperature and composition gradients but have high capital costs and high pumping costs as compared to an open duct. Helical bent coils find extensive use as motionless mixers owing to the cross sectional mixing induced by centrifugal force. The sudden shift in the direction of centrifugal force in bent coils is more effective than a gradual change in coiled coils in order to narrow the residence time distribution.

Bubble columns are mass transfer and reaction devices in which one or several gases are brought into contact and react with the liquid phase or with a component dissolved or suspended in it. The mass transfer stages, may take place before or after the chemical reaction itself. Several investigation of flow behavior in multiphase flow has been done, but most of the work is limited to water/air system. The aim of this study was to evaluate the influence of the test reaction NaOH/CO2 on the hydrodynamics in bubble column reactors.

An attempt has been made to cover the fundamental aspects of fluid flow, together with heat, mass and momentum transfer, relevant to non-agitated three-phase reactors. The state-of-art reviews on design criteria for the gas/liquid/solid reactors has been discussed. The industrial examples have been compiled which illustrate the combination of reaction-specific micro- kinetics with the macro-kinetics derived from the fundamental aspects of fluid flow, together with heat, mass and momentum transfer. A book entitled "Three-Phase Sparged Reactors" edited by K.D.P. Nigam and A. Schumpe has been published, Gordon and Breach Publishers (1996).

A three-phase fluidized bed is formed when solid particles are fluidized with cocurrent upward gas and liquid flows. Mass transfer and effective shear rate in the three-phase fluidized bed were investigated experimentally. A uniform correlation was developed for the liquid phase volumetric mass transfer coefficient in the three-phase fluidized bed with viscous liquids.

Multiphase reactors are found in diverse applications such as manufacture of petroleum based fuels and products, in production of commodity and specialty chemicals, pharmaceuticals, herbicides and pesticides, in refining of ores, in production of polymers and other materials and in pollution abatement. In all such applications, the knowledge of fluid dynamic and transport parameters is necessary for development of appropriate reactor models and scale-up rules

Bubble column reactors, with and without suspended solids and in many configurations, are frequently applied in industry for various chemical processes. Industrial bubble columns are often operated at high temperatures and at elevated pressures. Despite this fact, considerable effort has been made to understand the design and scale-up of these reactors at ambient conditions, and it was generally believed that experimental results obtained at atmospheric conditions are suitable for the design and scale-up of bubble columns at high pressures. The aim of the present proposal is to study in depth the gas holdup structure and mixing characteristics over a wide range of operating conditions and gas-Iiquid system properties, specifically, in organic liquids at elevated temperature and pressure.