AUTOMATIC
SELF-CLEANING
ELECTROSTATIC
PRECIPITATOR SYSTEM
REDUCES COSTS AND
BEATS EMISSIONS
STANDARDS FOR
POLYFLOR
ooking to minimise the
TCO on a replacement
electrostatic precipitator
(ESP) system, flooring
manufacturer Polyflor
has chosen an innovative new design
from ThermTech. Judged to be the most
cost-effective option to remove plastisol
emissions from flue gases, the new ESP
unit incorporates a revolutionary cleaning
system that effectively eliminates down-
time for maintenance.
L
Polyflor is a leading producer of PVC
flooring and has been manufacturing in
the UK since 1915, as such the company
takes its environmental responsibilities
very seriously. It is constantly looking to
improve its carbon footprint and that
of its suppliers as well as minimising its
impact on the environment.
ThermTech was involved in installing a
16,000 CFM, triple-stage air pollution
control (APC) unit at Polyflor's site in
Manchester over 25 years ago. Over the
years ThermTech has continued to provide
technical support for that unit, which had
now reached the end of its service life. The
quality and engineering support aspects
of what ThermTech could provide were
therefore well established, the decision
came down to which technology suited
the application best.
Regulations and standards relating to air
pollution have been tightened since the
original APC installation and now Polyflor
needed to find a replacement unit that
would meet future standards. There were
essentially five options available: a high
efficiency Venturi scrubber, a biological
scrubber, a coalescing candle filter, an
incinerator or a new ESP. The venturi
scrubber, coalescer and the incinerator
have very high energy costs associated
with them while the biological scrubber
requires a large area for the installation.
58
PECM Issue 30
In the past ESPs had developed a
reputation for being very efficient to run
and very effective, but costly to maintain
due to the cleaning requirement. In fact,
ESPs have the highest collection efficiency
for sub-micron particles, the ability to
recover the captured products, and the
lowest electrical running cost per unit
volume of air throughput of any of the
five pollution control devices.
However, the efficiency with which
ESPs can remove solids, moisture and
thermal degradation products from flue
gases causes the precipitator and its
associated gas cooling equipment to
eventually become blocked. This requires
them to be cleaned, sometimes off-site,
which until now, resulted in downtime
for the manufacturing process they are
associated with.
ThermTech had completed a considerable
amount of research into solving
this problem and now there was an
opportunity to prove the theory.
ThermTech approached Polyflor with a
proposal to install a pilot plant that could
be used to evaluate the technology.
Successfully winning a government
development grant, ThermTech
manufactured the prototype equipment
and installed it at Polyflor's Manchester
site, where it was connected to a stream
of flue gas. Over a period of several
months the process was fine-tuned
until the ESP cells could be washed
periodically, or on demand, automatically
and be brought back online within 2
minutes of the cycle ending.
Lionel Macey, Technical Director at
ThermTech, comments: "The process was
closely monitored and found to remove
99.5% of contaminants from the flue
gas stream, while the new automated
cleaning process enabled this to remain a
continuous process.
By removing the need for periods of
downtime to disassemble the unit to
manually clean it, ThermTech has re-
established ESPs as a prime low energy
abatement plant (LEAP) product."
Following the successful conclusion of the
pilot scheme ThermTech has applied for a
patent for the technology in the cleaning
process, which was one of the conditions
attached to the government loan. It has
also designed, built and installed a full-