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Tetra Technologies
Plant Installation
CASEBOOK: Handling Abrasive Sludge Materials
with Wear Resistant Pipe Linings
As seen in Pollution
Engineering, August 2005 issue.
Tetra Technologies,
East Chicago, Ind., processes mill scale from steel making
and rolling to separate the oil and steel filings. Mill scale
is jagged, irregular shaped steel filings that range in size
from 8-mesh to 8-microns, and according to a Tetra Waste Management
Division representative, "will tear up anything."
The facility was
the only plant of its kind in the world, using a proprietary
process consisting of heat, agitation and surfactants to remove
oil from steel for recycling. During the process, mill scale
was pumped through three separate tanks at the rate of 160
to 200 gallons a minute. Approximately 50 percent of the pumped
material was composed of solids.
Mill scale shown with
new lined elbow. |
Within months of its startup in the fall of
1990, the facility, which ran 24-hours a day, was operating
at only 80-percent efficiency. The extremely abrasive mill
scale was literally destroying elbows every five days to two
weeks. "The elbows were blown all the way through,"
said a maintenance foreman.
Anywhere the flow changed direction, the vortice
elbows and fabricated steel piping that was initially installed
wore out almost faster than they could be replaced. The company
was also having problems with tank outlet spools. The downtime
was costing the company operating efficiency and $600 per
hour.
As a test, in November 1990, the company ordered
six 2.5-inches inside diameter spools with special flanges
from Abresist Corp. of Urbana, Ind. After monitoring the spools
and finding that they withstood the abusive environment, the
company decided to put the new materials to the ultimate test.
They installed a basalt-lined radius, 2.5-inch inside diameter
elbow from the same company. After several months, the elbow
showed virtually no signs of wear.
Elbows such as these used
to needed replacing every 5 to 14 days. Now with Abresist
abrasion resistant elbows they last several months. |
Tetra had found the solution to its problem.
Over the next few months the company refitted the plant with
over 100 feet of basalt-lined straight pipe, 26 special spools
and fittings such as elbows, laterals, and tees. The company
also had Abresist design and install a high-density alumina
ceramic splash and diverter plate.
"We had tried so many things that didn't
work. Now we have little pipe related downtime and when we
do, we can plan it," said one company spokesman. "Abresist
has saved us a tremendous amount of downtime. And operating
efficiency has increased from a low 80 percent to a more acceptable
91 percent."
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