Something big has happened at Harsco Industrial Air-X- Changers (Harsco AXC),
which makes air-cooled heat exchangers for the natural gas industry. The Catoosa, Oklahoma-based
company has shipped the largest
coolers in its 60-year history.
Weighing in at 180,000 lb. (81,647
kg), the Model 204-3Z coolers are
75 ft. long, 25. 9 ft. wide and 14 ft.
tall ( 22. 9 m long, 7. 9 m wide, 4. 3 m
tall). In late September 2013, Harsco
AXC shipped the first of four units to
a customer that will use the coolers
in offshore natural gas operations in
the Gulf of Mexico. A second unit left
the Harsco AXC plant in mid-October,
with the remaining two departing in
November and December.
“We knew from the beginning that
the sheer size and complexity of these
coolers would pose unique challenges,” said Eric Clower, Harsco AXC’s
vice president and general manager.
The planning process started
in late 2012, said Mike Thomas of
Eads & Associates, the Houston-
based sales firm representing Hars-
co AXC in the project. The goal,
he said, was to provide the largest
cooling apparatus possible for the
offshore platform. Doing so created
a new challenge — meeting highway
and shipping regulations, which the
“It was the biggest cooler that we
could build, ship and put on the platform,” Thomas said.
The Harsco AXC Model Z — a bolted-together horizontal cooler designed for
high-horsepower, high-volume applications — was the company’s choice,
based on the unit’s ability to fit into a
wide range of gas compression and
“The customer’s compressor pack-
ages are designed to handle huge
amounts of gas,” Thomas said. “Com-
pression raises gas temperature, so
cooling is very important.”
To achieve the needed cooling, gas
will flow from the compressor through
a six-row assembly of 64 ft. ( 19. 5 m)
long finned cooling tubes in the Hars-
co AXC unit. Three 17 ft. ( 5. 2 m) di-
ameter fans, each driven by a 60 hp
(44.7 k W) electric motor, will force air
across the tubes to cool the gas.
The Model Z fans are normally 168
in. (427 cm) in diameter, said Sean
Williams, an application engineer with
Harsco AXC. The cooler units have
fans that are 20% larger (204 in. [518
cm]) than the standard models.
The plates that form the cooler’s
headers — the gas-inflow/outflow
units that channel the gas through
the cooling tubes and lock the tube
assemblies in place — are 4 in. ( 10. 2
cm) thick and weigh 12,000 lb. (5443
kg) each, four times the thickness of
normal Model Z header plates.
Although Harsco AXC has 315,000
sq.ft. ( 29,264.5 m2) of manufacturing
space, the company still had to adjust
for the production of the coolers. Williams said the coolers and their components nearly filled an entire bay.
Harsco had to build 9 lb. ( 4. 1 kg) lifting
lugs just to move them.
The size of the coolers brought
additional challenges, such as their
use in sour gas compression. Since
hydrogen sulfide (H2S) gas would
flow through the unit, ASME requirements would have to be met. Those
standards meant there was no leeway for leaks, especially when dealing with toxic compounds, said Allen
James, a Harsco AXC manufacturing engineer.
Manufacturing the headers and
cooling tube assembly of each cooler
required 6000 welds, James said. This
amount of labor prompted Harsco
AXC to turn to automated orbital welding technology from Maus Italia. The
company worked on the project using
a manual tungsten inert gas welding
process but as the work progressed,
Harsco AXC relied on the Maus Italia technology for most of the welds,
“The Maus system cut weld time by
over 50% with comparable improvements in weld quality,” he said. “Like
any other piece of automation, the
Maus will do the same job over and
over, hundreds of times, in exactly the
same way.” CT2
Supersized Heat Exchangers
Shipped > Harsco AXC builds largest coolers in company’s history
BY DJ SLATER
n Harsco AXC employees ready one of the supersized Model 204-32Z coolers for road transport.