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Microchannel technology as applied to chemical processing has resulted in impressive improvements in performance thresholds. Studies published for more than a decade show that enhanced performance in chemical reactors can be largely attributed to the reduction of transport distances. Chemical distillation is now emerging as a new area for the application of microchannel technology.A simplified method for simulating a microchannel distillation process has been developed and validated with experimental data. Both simulation and experiments show that the height of a theoretical transfer unit for the separation of hexane and cyclohexane in a microchannel distillation unit is reduced to centimetres. Vapour-side resistance was found to control mass transfer for the cases considered. The current simulation can serve as a tool for optimizing and refining the design of multiphase microchannel processes.

The Advanced Distillation project was concluded on December 31, 2009. This U.S. Department of Energy (DOE) funded project was completed successfully and within budget during a timeline approved by DOE project managers, which included a one year extension to the initial ending date. The subject technology, Microchannel Process Technology (MPT) distillation, was expected to provide both capital and operating cost savings compared to conventional distillation technology. With efforts from Velocys and its project partners, MPT distillation was successfully demonstrated at a laboratory scale and its energy savings potential was calculated. While many objectives established at the beginning of the project were met, the project was only partially successful. At the conclusion, it appears that MPT distillation is not a good fit for the targeted separation of ethane and ethylene in large-scale ethylene production facilities, as greater advantages were seen for smaller scale distillations. Early in the project, work involved flowsheet analyses to discern the economic viability of ethaneethylene MPT distillation and develop strategies for maximizing its impact on the economics of the process. This study confirmed that through modification to standard operating processes, MPT can enable net energy savings in excess of 20%. This advantage was used by ABB Lumus to determine the potential impact of MPT distillation on the ethane-ethylene market. The study indicated that a substantial market exists if the energy saving could be realized and if installed capital cost of MPT distillation was on par or less than conventional technology. Unfortunately, it was determined that the large number of MPT distillation units needed to perform ethane-ethylene separation for world-scale ethylene facilities, makes the targeted separation a poor fit for the technology in this application at the current state of manufacturing costs.

A modelling approach to predict and enhance understanding of the dispersion phenomenon is presented. The discrete/distinct element method (DEM) is adopted to study the behaviour of single linear and spherical agglomerates, immersed in a simple shear flow field, in response to shearing under steady or dynamic/oscillatory flow conditions. The effects of hydrodynamic forces, which result from both the straining and rotating components of the flow, and cohesive forces of interaction, comprised of short range van der Waals attractive and Born repulsive forces, are considered. Simulations of simplified linear agglomerates demonstrate the ease with which the simulation can probe the fundamental effects of varying types of interaction forces. Comparative results of the three-dimensional simulation of the dispersion of spherical nanosize silica agglomerates in response to steady and unsteady shearing are found to be in good agreement with reported experimental trends. The current model allows probing and prediction of the dispersion phenomenon as a function of processing conditions, agglomerate structure/morphology and material properties and interaction forces. List of symbolsa radius of the agglomerate A Hamaker constant for the cluster material Amp amplitude of oscillation of the plates relative to one another eff locFa effective local fragmentation number for the system F c ij cohesive force acting on the individual cluster because of its interaction with another neighbouring cluster F d i drag force exerted on the individual cluster by the surrounding fluid F h k i hydrodynamic force acting on the individual cluster through part of its exposed surface area k ĩ F i net force acting on the individual cluster L gap between upper and lower plates m mass of each cluster OSC oscillatory run indicator r,h,w spherical system coordinates R radius of each cluster STD steady run indicator t osc , t 1 osc period of oscillation, with and without dimensions respectively t refc , t ref d , t ref h characteristic time scale for the cohesive interactions, drag effects and hydrodynamic interactions t std rot , t 1 std rot period of rigid body rotation for the agglomerate in steady shearing, with and without dimensions respectively x,y,z Cartesian system coordinates ::x i acceleration of the individual cluster a rotation angle of the rotor driving the relative motion of the plates c net strain for the agglomerate : c, : c steady , : c mean , : c max nominal, steady, mean and maximum shear rate for the flowing fluid Dt time step for the simulation Dt* dimensionless time step for the simulation m f dynamic viscosity of the dispersing fluid r density of the cluster material s separation distance at which the interatomic potential of the cluster material is zero t, t mean , t max nominal, mean and maximum applied hydrodynamic stress