Chemical Engineering June 2023 - 32

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countries. PED is an E.U.-based
regulation that imposes similar safety
and design requirements for pressure
equipment.
These regulations further define
design and safety parameters for
filtration systems, fluids in use and
system operating and ambient conditions.
In all cases, it is important to
ensure a filtration solution carries the
required stamps and approvals by
third parties, denoting the equipment
has been built to the highest level of
safety and has undergone assessment.
At times, required certifications
may further demand CE marking in
accordance with PED based on the
EN 13445 or AD 2000 pressure vessel
codes.
FIGURE 2. Industrial filters must be made from materials that meet the stringent safety, sanitation and quality
requirements for industries like paints and coatings, and specialty chemicals
tent quality, where product designs
and materials do not waver in terms
of performance, safety or dependability
- regardless of where they
are made.
Filters with oil-adsorption capabilities
can further offer a solution to
paint manufacturers that must ensure
batches remain fit for end-customer
use. Pure non-lubricated plastics,
such as polypropylene, feature
oleophilic and hydrophobic characteristics
that attract oils to their surface
while repelling water particles.
These filters are commonly used in
paint baths within the automotive industry,
either as a remedy or preventive
measure.
Environmental safety
In many CPI facilities, system operators
must wear protective gear, including
masks, to change out dirty
consumable filter media, such as filter
bags and filter cartridges. Limiting
maintenance intervals at these points
to the bare minimum is important,
since volatile organic compounds
(VOCs) can be released when opening
filtration units to change consumables.
VOCs can be either naturally
occurring or synthesized, but tend to
have high relative vapor pressures,
meaning they easily evaporate when
exposed to air.
Maintenance needs will largely
depend on the type and capacity
of the selected filtration equipment.
32
Filtration systems must be designed
and adequately sized to operate for
long intervals between changeouts.
Often the goal is to go weeks or
even months between changeouts
of consumable filter media. This
helps to limit the risk of introducing
industrial solvents into the production
environment each time a unit
must be serviced.
Facility operators are advised to
consult an industrial filtration expert
about options for large-capacity
systems or, in other cases, automatic
self-cleaning systems (Figure
3) that greatly reduce the need for
manual intervention. The market offers
many configurations and features
that can extend the time between
consumable filter changeouts
- an expert can help you strike the
right balance between frequency
and dollars spent.
Also, housings for filtration units
- as long as they are pressure vessels
- must be properly certified.
The American Society of Mechanical
Engineers (ASME) Boiler and Pressure
Vessel Code (BPVC) and the
Pressure Equipment Directive (PED)
are two major standards that ensure
the safe operation of pressure equipment
worldwide. The ASME BPVC
was established as a set of procedures
for the design, manufacture
and use of boilers, pressure vessels
and piping, and is used in the U.S.
and Canada as well as in many other
Other considerations
Many factors affect the efficiency
and effectiveness of filtration processes
in chemical manufacturing
and processing applications. These
include the size of the particles to be
filtered, filter media pore size, fluid
viscosity, system temperature and
pressure, and the concentration of
the suspension. To ensure optimal
performance, industrial filtration systems
must be designed to account
for these requirements.
For instance, a filtration system
can be too efficient - and costly
- if desired substances are filtered
out along with impurities. Particle
sizes can range from as small as
0.1 µm (for example, bacteria) to
Eaton
FIGURE 3. Automatic mechanically cleaned
filters, like this commercial system, can provide
continuous flow, simplified maintenance and
worry-free operation because there is less risk
of harmful VOCs being released in the production
environment
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Chemical Engineering June 2023

Table of Contents for the Digital Edition of Chemical Engineering June 2023