報告題目：Development of continuous flow microreactors for fast liquid and liquid-liquid reactions
報告嘉賓：Arturo Macchi 教授 渥太華大學
Continuous operation presents multiple advantages over batch chemistry, yet its usage in the fine chemical and pharmaceutical industry remains limited due to its complexity. A holistic tool-box approach for process development is presented such to facilitate technology transfer. Reaction kinetics and reacting phases are taken into consideration for the selection of the most appropriate reactor and operating conditions. A micro-reactor for fast liquid and liquid--liquid reactions is then more specifically developed. The yield of competitive parallel reactions was used to characterize mixing in the single phase system whereas a reactive liquid-liquid extraction was used to investigate interphase mass transfer and resulting flow regimes in the two phase system. The effects of phase physical properties, mixer geometry, method of energy input and scale were measured and analyzed such to optimize the reactor design. A key finding is that mixing and interphase mass transfer is a scalable function of the average rate of energy dissipation once the flow has reached turbulent flow (single-phase system) and drop flow (two phase system), independent of reactor geometry, indicating that efficient micro-mixers achieve these flow conditions at the lowest possible energy dissipation rate. Moreover, multiphase micro-mixer geometries that are based on contraction-expansion repeating units with alternating asymmetric obstacles to aid the breakup of the dispersed phase, and desynchronize the recombination of split streams are most effective.
Professor Macchi did his BEng and MASc at Ecole Polytechnique de Montréal and attended the University of British Columbia for his PhD. Research interests are in fundamental and applied multiphase reaction engineering with emphasis on fluidized beds. Some current projects are: Investigation of the hydrodynamics and transport phenomena in heavy oil hydroprocessors (e.g., LC-FinerSM) for yield improvement, Development of continuous multiphase flow micro-reactors for intensifying the synthesis of fine chemical and pharmaceuticals, Synthesis of gas hydrates in a slurry bubble column for the transportation of natural gas, and power production with CO2 capture via cyclic carbonation/calcination of lime-based sorbents or reduction/oxidation of metal oxides. Collaborations have been established with academic, government and industrial research institutions.