Plastics Cleaning Equipment
The number of North American businesses involved
in recycling post-consumer plastics has tripled in the last few
years to more than 1,800, according to the Association of Postconsumer
Plastic Recyclers. That’s good news for plastic cleaning systems
The trend today is toward larger, higher-capacity systems, according
to Curt Cozart, sales agent for Sorema in Montclair, New Jersey.
“Ten years ago, a one ton per hour system was typical. Now a
typical plant would be a three ton per hour system.”
Sorema emphasizes use of automation to reduce the number of human
operators required to run its systems, Cozart says. In another
move to cut cost of operation, the company also seeks to reduce
use of water for cleaning and electricity for running the machines.
“We don’t have as many people and we’re managing our water and
electricity very well,” Cozart says.
Sorema’s plastic washing systems tend to be heavily customized,
based on the nature of the recycling stream. The most popular
recycling materials today are PET bottles and HDPE bottles, with
plastic film in the form of grocery bags and stretch film also
coming on strong.
“With PET you have to be in the low parts per million of total
contamination because it’s going to make a bottle or something
of very high quality,” Cozart says. “And it’s clear so they don’t
want black spots.” Because PET bottle labels are applied with
hot melt glue, cleaners employ a hot chemical solution to dissolve
HDPE streams don’t have to be quite so clean. “You don’t have
the clarity issues,” Cozart says. “Your glue is also water-based
in most cases and your labels are paper. So it’s a little easier
to clean.” Another difference is that, unlike PET which is heavier
than water, HDPE floats in water.
With grocery bag cleaning systems, the issue is handling the
plastic film material. “It just doesn’t flow very well, particularly
when it’s wet,” Cozart says. Also, because film is much thinner
than bottle plastic, the cleaners must wash far greater surface
area per pound of output. “The system really needs to be designed
to handle those types of things.”
Because of the differences in the way common plastics must be
handled, Cozart says most equipment sold today is for systems
designed to handle one type of plastic. “Each one of the polymers
and each one of the shapes has something special to it,” he says.
“So the lines are very specialized. There aren’t any general-purpose
lines any more. We had them 20 years ago, but those lines pretty
much have become specialty lines.”
At Polymer Recovery Systems in Eau Claire, Wisconsin, President
John Ayres says the company’s Float/Sink Tank is one of its most
popular products today. The Float/Sink Tank is used to separate
plastic regrind from other materials in the stream. Ground materials
are deposited in the tank that contains a water solution with
a specific gravity that can be altered to suit the situation.
Materials heavier than the solution sink to a sloping bottom
and are removed.
Many Float/Sink Tank customers are industrial users recycling
shop scrap. “A lot of times people will have a plastic that floats
in water and, if it’s floor sweepings or whatever, they can run
it through this and it will separate the dirt from the plastic,”
Polymer Recovery’s PlastiCycler is a complete system that incorporates
an air classifier, washer, de-waterer and dryer for shredded
plastic, as well as a secondary air classifier for use after
the plastic is granulated. The washer/dryer portion employs a
series of rotating drums where material is sprayed with hot water.
Contaminants are removed through the combination of heated water
and rubbing against other particles in the drums, and washed
out through screens.
After de-watering in another set of drums, air heated by gas
or electricity is blown through to complete the drying.
The PlastiCycler is more likely to be used in post-consumer applications.
“That’s where a more thorough washing is necessary, where you
may have residue like food residue or glue or labels,” Ayres
says. “This provides a more aggressive washing and cleaning of
The air classifiers are important components of the cleaning
process, Ayres says. In these, material is deposited on a column
of air which carries lighter materials up and out of the system
while heavier materials fall through. The PlastiCycler capacity
is normally one ton per hour, put Ayres says they are studying
increasing the capacity. “We see some market applications where
people are calling for higher throughput,” he says.
In Ipswich, Massachusetts, EREMA North America takes a different
approach to removing contaminants from plastic grocery bags.
CEO Tim Hanrahan says the company’s recycling system directs
a constant flow of melted plastic through a pair of disks, each
of which has up to one million tiny, laser-drilled holes. Laser
filters with different-sized holes can separate particles of
The laser filter doesn’t clean well enough for applications where
there are more stubborn contaminants than are typically found
in grocery bags. “If you have really bad stuff, you need a washing
system. But if you have stuff you can be selective about, they
may get away with this laser filter,” says Ayres.
Most of the more than one billion pounds of PET bottles collected
in North America for recycling annually, are shipped to other
countries for recycling. However, vendors of plastic washing
systems see good, long- term domestic demand as long as high
oil prices make virgin plastic more expensive.