| When the frigid cold of an Alaskan winter
freezes the tundra so hard it resembles concrete, uncovering buried crude oil pipelines
for routine maintenance is hard work. The Ground Heater, a new piece of equipment
currently in use thawing ground at pumping stations on the TransAlaska pipeline, is making
that job a lot easier. The portable units have thin-walled rubber hoses with a filament
for strength through which a hot water-propylene glycol fluid is pumped. When it’s
cold, a heater warms the fluid so it can circulate. The hoses are laid on the ground and
are then covered with a vapor barrier. Two to three layers of insulation blankets are
added to keep in the heat.
"You set it up, let things cook for a few days and it’s just like
summer," says Ken Broker, a sales representative for Airport Rentals in Prudhoe Bay,
Alaska, which rents the units.
"The Ground Heater can deliver heat directly to what you want to heat and
you’re not wasting dollars heating what you don’t want to heat," adds Sue
Meekhof, vice-president of sales for Ground Heaters, Inc. in Spring Lake, MI.
The company began work on the first prototype about 4 ½ years ago. Today, the business
is split roughly 50-50 between ground thawing and concrete curing applications, says
Meekhof.
While Ground Heaters manufactures and sells many models, including two large units: the
E3000 (with 3000 feet of hose), which can be towed behind a pickup truck, and the new V60
(with 6000 feet of hose) that can be either trailer of skid-mounted. The larger unit was
developed at the urging of TransAlaska pipeline officials, who bought four this year for
maintenance purposes, says Meekhof. The heavy-duty V60 model includes a larger 400-gallon
fuel tank with a 110-hour continuous run time between refuelings, eliminating the need for
continuous monitoring as with steam heating. The V60 can thaw up to 12,000 square feet of
ground at a time. On a road crossing, the unit sat on site for three days, thawing the
ground to a depth of 1.4 metres (4.5 feet), says Broker, who previously was the heavy
equipment coordinator for Houston/NANA, a maintenance contractor on the Alaska pipeline.
"We went in and it was just like digging in the summertime."
The Ground Heater
is cost-efficient, saving not only time and labour, but also wear and tear on equipment
used on frozen ground, says Broker. In Alaska, all maintenance is done inside the
fenced-off pump station, which means work must be done by hand using jackhammers. With hot
air heaters, "it takes forever to thaw the ground," he says. "And if you
don’t thaw it, you spend two or three days digging something you can dig in one and a
half or two hours it it’s thawed."
Although thawing frozen tundra may offer the most dramatic example of what the Ground
Heater has to offer, the hoses provide the flexibility for a variety of applications for
the units. In Canada, where the company is just beginning its push, the E3000 model was
tested on a newly laid Enbridge Energy Inc. pipeline near Morden, Manitoba, says Tom
Thornton, a Canadian Ground Heater agent. To protect the 200-foot section of the line from
freezing during pressure testing, hoses were looped over it and covered with insulation
blankets. Pressure testing was able to proceed at least a day earlier because the usual
polyethylene tent with propane direct-fired heaters wasn’t necessary, he says.
The unit was also able to deliver the necessary heat from outside the 75-metre
restriction zone at a test site adjacent to a gas compressor station where open flame
propane heaters are prohibited. The cost savings were considerable, says Thornton. The
daily (24 hours) cost for a Ground Heater was $672, including $59 for fuel, compared to an
estimated $3,415 to build a tent and heat it. – Elsie Ross
Contacts:
Sue Meekhof, Ground Heaters, Inc., 231-799-9600, ext. 202, Fax: 231-799-9500, Email:
info@groundheaters.com
Tom Thornton, Tom Thornton & Associates, 250-546-6847, Fax: 250-546-8628, Email:
tta@junction.net |
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