ie302567d_si_001.pdf (509.19 kB)
Scaling-up a Confined Jet Reactor for the Continuous Hydrothermal Manufacture of Nanomaterials
journal contribution
posted on 2013-04-17, 00:00 authored by Robert
I. Gruar, Christopher J. Tighe, Jawwad A. DarrA confined jet reactor (mixer) is presented as a novel solution
for the scalable continuous hydrothermal flow synthesis (CHFS) of
nanoceramics. In CHFS, nanoceramics are formed upon mixing of two
streams consisting of an aqueous metal salt solution at room temperature
with a flow of less dense supercritical water (at 240 bar and 450
°C). Upon mixing, hydrolysis and dehydration occurs, resulting
in the particles being formed in a continuous manner. The confined
jet mixer used herein overcomes previous designs of mixers that can
accumulate material internally and block. A method for scaling up
the jet mixer (reactor) is described, to determine the size of jet
mixer (internal mixer diameter 13.5 mm) prior to its use in a newly
commissioned pilot plant designed to process flow rates 40 times greater
than the equivalent laboratory-scale process (internal mixer diameter
4.6 mm). It was confirmed that the pilot plant scale mixer allowed
safe and continuous operation with no blockages at much higher concentrations
(i.e., higher molarity) of metal salt precursor than laboratory scale
because of the higher velocities and larger physical dimensions of
the mixer. Consequently, the pilot plant was used to manufacture nanoparticles
at a rate >400 times that of the laboratory-scale process. The synthesis
of zinc oxide nanoparticles was used as a model to compare the properties
of particles produced on different production scales. The same model
system was also used to assess the limitations of a scale-up strategy
based on mass (i.e., increasing the molarity of the metal salt).