11, Number 3
A Gossman Consulting, Inc.
The first permanent,
professionally designed tank farm for storage and feeding of hazardous
waste fuel at a cement plant was built in 1980 at the General Portland
Cement plant in Paulding, Ohio. Because General Portland was
company with headquarters in Dallas, Texas with connections to the oil
industry it was natural for the company to use an engineering firm with
oil industry experience to design the system. While the
set a new standard for the time it was not without difficulties and a
significant learning curve.
is part of a
series of GCI Tech Notes focusing on the early
development of the hazardous waste fuels programs during the early
1980s. I was hired as the facility manager for the first
hazardous waste operation at a cement plant in early 1980.
developments in storage, processing, testing and use of hazardous waste
fuels were the result of work done at a handful of plants in the early
and mid 80’s. Look for issues to include topics on
testing methods, processing and the impact of HWF on cement product
quality and production.
Tank Farm Design and Operation
– The Early
David Gossman, Gossman Consulting, Inc.
The original tank farm had four 25,000 gallon tanks with 7hp
side-mounted agitators. The concrete secondary containment
did not have anything more than a stone floor and included an oil/water
separator on the drainage system. Tanks were set on ring
foundations rather than solid slabs. Differential pressure level
indicators and alarms were part of the original design as were
impeller-style flow meters. Obviously, changes were made
very quickly. The flow meter shut down and stopped the flow
the first truck we tried to offload.
Another interesting early feature was that all trucks were offloaded
with truck-mounted pumps; usually PTO driven Roper pumps, although some
were hydraulically driven Blackmere pumps. Either way, the
that connected the truck to the facility operated under pressure, not
suction, as is currently the case, and they required draining at the
end of each truck unloading. Most trucks actually provided
own hoses as well. The facility used a sealed concrete sump
drain hoses and hose ruptures were known to occur. All
was filtered through a large basket filter. The filter was two feet
across and an early improvement that I installed was a winch and pulley
system to lift the lid off the filter. When I first started
off-loading trucks in Paulding, the plate steel lid was heavy enough
that I could barely get it off and on the filter by myself.
Similarly, the filter was also large and cumbersome so the winched
pulley system was a big improvement. On at lease one occasion
filter was over-pressurized and sprayed waste fuel.
From the beginning centrifugal pumps were used to pump fuel from the
tanks to the kiln through a loop. Because of the size of the
pumps and recirculation loop the early fuel spec for viscosity was
about 32cp max, much lower than today’s typical max of
Maintenance of the pumps was an early headache. The fact is
an extra large pump operating at a low speed is the way to minimize
wear and tear with the abrasive materials that have always been found
in hazardous waste fuel. That was a lesson learned early in
Early facilities at cement plants did not have grinders – if
material would not pass through a filter it was considered out of
spec. Eventually market and regulatory pressures required
systems have the ability to grind solids instead of filter
Early systems included Greerco grinder-pumps and Muffin
One of the early systems I designed for the Clarksville plant included
a motorized Sarco strainer that sent only that portion of the stream
that did not pass the filter to the particle sizing system.
Today’s systems that require all the fuel flow to go through
grinders continue to create maintenance headaches.
A problem that has occurred over the years a number of times is plugged
pipelines. This can happen for a number of reasons including:
· Polymerization or thickening
of material upon
· Laminar flow in pipes that
allows solids to settle
· Reaction of materials
resulting in solidification
It is important to realize that the viscosity of hazardous waste fuel
is non-Newtonian in nature. That means that the viscosity changes
depending on the sheer rate. Usually, but not always, the
viscosity of HWF is higher at low sheer rates. That is part
the reason it is sometimes hard to get HWF to flow using just a gravity
feed and the reason it is so easy to cavitate a pump while starting up
a HWF system. Systems and procedures for removing air from
are important to safe operation and the minimization of associated
damage to pumps.
Another early feature of the first HWF tank farm in Paulding was the
use of activated carbon to control vapor emissions. The
firm, familiar with controls for oil storage, was not aware of the
incompatibility of activated carbon and ketones such as acetone and
MEK. This was another system that required early intervention
avoid an accident and fire. I am aware of at least one HWF
facility that had a fire in their carbon canisters because they were
unaware of this potential. I continue to advocate the use of
conservation vents and vapor balance systems for primary control of
fugitive emissions from HWF tank farms. If additional levels
control are required the use of refrigerated condensers or pressure
tanks may be warranted. Another early practice that should be
avoided is the use of air to transfer fuel or flush lines.
Bubbling air into a tank of HWF can create a highly explosive
atmosphere in the head space of the tank and the bubbles moving up
through the liquid can build up a static charge creating the spark that
sets off the tank. Line flushing should be done with
nitrogen. Many facilities now have liquid nitrogen tanks on
and use that nitrogen for flushing lines.
contact David Gossman at 847-683-4188 or
by e-mail at email@example.com
for additional information – or if you have memories to share.