H.E.N.C.I. DISPERSED-PARTICLE BED TECHNOLOGY AND THE ADVENT OF HIGH MASS-AND MOMENTUM- TRANSPORT EFFICIENCY NANOCATALYTIC UNIT OPERATIONS

摘要

When employed in-situ, many new nano- (and micro-) sized catalyst particles/structures have been shown to effect extremely favorable (rapid) extrinsic kinetics~[1'4] largely due to their great surface-area/mass ratios. This effect is extreme in catalytic scenarios in which the rate-limiting step(s) include mass transport to/from the catalytic surfaces (such as a packed-bed reactor being fed with an ultra-dilute-solute reactant), and has extremely positive economic ramifications for applications requiring high-throughput, high-conversion and high-mass- (& momentum-, & often heat-) transport efficiencies to achieve cost-effective operation (hereafter acronymed HTCT3 applications). Rapid overall kinetics hold the potential to greatly increase process efficiencies of niche catalytic CPI processes as well, and the desire to use these highly effective catalysts for various CPI as well as large-scale GWR applications has been a natural consequence. Catalytic nanoparticles themselves, often toxic, are however, rarely desirable in any product stream, thus their in-situ use usually necessitates that they be completely removed prior to product use, which is generally difficult in high linear-velocity processing: Because these particles are so small (and numerous), very robust (e.g. N.F or R.0.) operations would often be required to assure such removal, rendering most in-situ HTCT3 nanocatalytic operations extremely cost-prohibitive. Conversely, ex-situ use of nanocatalysts (immobilizing them in such a way as to thoroughly exploit their advantages in a flow-through reactor both safely and cost effectively) has been stymied as well. Why? Until the advent of High-Efficiency Nano-Catalyst Immobilization (H.E.N.C.I.) technology, the following seven engineering criteria inherent to immobilizing nano-sized particles for cost-effective ex-situ HTCT3 catalysis had proven insurmountable: HENCI technology alone meets these criteria, thus comprising the 'last piece in the puzzle' of unleashing the true power of nanocatalysis outside the lab by safely exploiting it's highly favorable kinetic and transport rates, especially in HTCT3 applications such as large-scale remediation of our now-carcinogenic groundwater supplies (see below). The micro-homogeneous, ultra-high-density, ultra-low pressure-drop dispersion accomplished within the tubular HENCI reactor has come to be known also as the Dispersed Nano/Micro-Particle Reactor Bed, or HENCI DNP reactor for short. Dr. Mamadou Diallo at the Beckman Institute/Power, Environmental & Energy Research Center, both of Cal Tech; Dr. Michael Wong et. al. at CBEN / CNST, Rice University, and Drs. Peter Rony, Dr. John Y Walz Jr., and Dr. Preston Durrill et. al. of Virginia Tech's Ch.E. department are currently evaluating and developing new GWR and CPI applications and process scenarios using HENCI DNP units. Several other universities are also in the process of obtaining HENCI DNP systems.