Chemical Engineering April 2022 - 22

Cold Jet
FIGURE 2. Dry ice cleaning uses solid carbon dioxide pellets or microparticles, which are blasted at supersonic
speeds and sublimate on impact, lifting dirt and contaminants off the underlying substrate. The
process is non-abrasive, non-conductive, non-flammable and non-toxic
radicals. Using TOMI's process and
products, these hydroxyl radicals
can kill bacteria and fungal spores
and inactivate viral cells by destroying
their proteins, carbohydrates and
lipids. This leads to cellular disruption
or dysfunction, allowing quick decontamination
of targeted areas, objects
and large spaces.
The technology offers no wipe, norinse,
no residue, non-corrosive, highlevel
efficacy, quick turnaround time
and superior material compatibility,
allowing it to be sprayed directly on
sensitive equipment, while the submicron
particles allow the mist/fog to
reach every area being treated.
The technology can be used to
disinfect and sanitize chemical, life
sciences,
food-and-beverage and
pharmaceutical process equipment,
laboratories and cleanrooms, as well
as general facility areas, according
to Shane. Traditionally, electrostatic
sprayers would have been used in
these applications, but they typically
spray large micron-sized droplets,
which develop a wetness that damages
surfaces. " Using our technology
to achieve very small sub-micron
sizes, we can get down to the level of
bacteria and virus to kill them, versus
drowning them with over-wetness
that damages materials and equipment, "
Shane says.
" Not only is it less damaging, but
it's faster and uses less manpower, "
22
he continues. " Users press a button
and fill a room to cover all surfaces
with minimal work and minimal
downtime because there is no rinsing
and it leaves no residue. On top
of that, we leave behind no toxic byproducts,
so it's ecofriendly. "
Dry-ice cleaning is also finding
applications in chemical processing
facilities, including those in the
life
sciences,
food-and-beverage,
cannabis, plastics, oil-and-gas and
any industry that requires a dry, nonabrasive
cleaning method, says Cold
Jet's Wilson.
Also known as dry-ice blasting,
dry-ice cleaning is an environmentally
responsible cleaning and surface
preparation technique, similar to
sand, bead and soda blasting in that
it prepares and cleans surfaces using
a media accelerated in a pressurized
air stream. However, it differs in that
dry ice cleaning uses solid carbon dioxide
pellets or microparticles, which
are blasted at supersonic speeds and
sublimate on impact, lifting dirt and
contaminants off the underlying substrate.
The process is non-abrasive,
non-conductive, non-flammable and
non-toxic. The dry-ice blasting process
also does not create secondary
waste as the dry ice sublimates,
or phase transitions, from solid CO2
to gaseous CO2 when it impacts the
surface being cleaned (Figure 2).
" As companies are getting more
serious about environmental and social
governance, they are looking at
their contributions to greenhouse gas
emissions, " says Wilson. " Since CO2
is naturally found in the environment
and dry ice is made from recycled
CO2, it doesn't count toward a processor's
greenhouse gas emissions,
as it has already been accounted for
at the source of the original emission.
Because it's a reclaimed substance,
it's a way to help reduce their carbon
footprint score, as it can be used in
place of solvents. "
Another eco-friendly aspect of dryice
cleaning is that it's a dry method
of cleaning, helping to eliminate the
use of water. " With other methods,
there is sometimes a residue left behind,
which needs to be removed.
With dry ice, there is no residue as it
sublimates, " says Wilson.
This also contributes to efficiency.
" We have case studies in industry
where a dozen employees performed
cleaning tasks using traditional
aqueous methods, but after
switching to dry ice, only one to
three people were needed. Dry ice is
faster because there is no masking
to protect areas that cannot get wet,
users don't have to wait for equipment
or areas to cool down before
cleaning and it is not necessary to
calculate the nature of the soil and
the concentration of solvent needed
to remove it as dry ice blasting can
clean any number of soils from any
number of substrates, " he says. " All
this comes together to simplify and
streamline the cleaning process. "
Minimizing cleaning time and water
Spraying Systems
FIGURE 3. Spraying Systems' motor-driven tank
cleaners, including the TankJet AA190, can help
resolve time, effectiveness and water usage woes,
as they can be slowed down or sped up via controls,
optimizing the process
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Chemical Engineering April 2022

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