Process Intensification for Energy

This presentation will discuss potential benefits of process intensification approaches based on recent advances in the field. Examples of a variety of process intensification techniques and devices will be drawn from the author’s research on specific chemical engineering applications. For instance, enhancement in transport rates in multiphase systems can be achieved by directly disrupting the interface via an externally applied field, rather than providing energy to the bulk fluid. Such an external field can be electric, magnetic, microwave, high gravity, etc. Electric fields, for example, have been employed to disrupt gas-liquid and liquid-liquid interfaces to form high surface area per unit volume for enhanced mass transfer and chemical reaction in multiphase systems. Electrostatic spraying, pumping, mixing, and phase inversion, as well as an electrohydrodynamic micromixing reactor developed at the Oak Ridge National Laboratory (ORNL) for fine particles production and water treatment, will be discussed. Multiphase reactive systems are very common in industrial applications. A multiphase reactive system was also the solution of effective storage of CO2 in the deep ocean. A three-phase gas-hydrate reactor operating at relatively high pressure was developed for CO2 injection in mid-ocean depths. This reactor forms a fine dispersion of liquid CO2 with surrounding seawater at ocean depths at which the thermodynamic conditions favor solid gas-hydrate formation. The solid hydrate material is denser than surrounding seawater and sinks to the bottom of the ocean. The reactor was successfully demonstrated off the coast of Monterey Bay, CA. Another approach to process intensification is combining unit operations, such as reaction and separation, in one system. An example of such a system is the centrifugal contactor developed at national laboratories for nuclear-energy related separations by liquid extraction. This liquid-liquid contactor has been modified into a system that can perform multiphase reaction and phase separation in one process. The combined reactor/separator has been demonstrated for the continuous production and separation of biodiesel. The same system is currently employed for the separation of the aqueous and organic components of bio-oil produced via biomass pyrolysis. The presentation will conclude with a discussion of current needs for advanced chemical processing for energy and other industrial applications.