Leaks are a huge problem for the oil industry. Even small
leaks from pipes, valves, boilers, heat exchangers,
etc., reduce efficiency and eat away at profits.
Indonesias state-owned oil and gas company, PT Pertamina,
suffered from leak problems in aging refinery and petrochemical complexes. This case
history explores how this operating company solved its sealing
Aging Asian downstream complex.
PT Pertamina was established in 1957. This national oil
company (NOC) engages in both upstream and downstream
activities. Upstream, PT Pertamina is active in oil, gas and
geothermal exploration and production. For the downstream, this
NOC refines, ships and markets transportation fuels, liquefied
petroleum gas (LPG), liquefied natural gas (LNG), petrochemicals and lube oil. The
company operates six refineries with a combined capacity of
1.046 million bbls. Two of the refineries are integrated with
petrochemical plants that produce
purified terephthalic acid (PTA) and paraxylene (PX). Five
other complexes produce LPG, and there are two LNG plants with
a combined 35,000 tpy incapacity.
Several of the refineries are older and predate
Indonesias independence and the establishment of
Pertamina. The Balikpapan refinery was established by Shell
Transport and Trading in 1894. The original facility was
destroyed during WWII, rebuilt in 1950 and expanded in 1983.
The 2.5-km2 facility has two sub-units, which
processes up to 260,000 bpd and produce fuelsaviation
turbine fuel (AVTUR), aviation gas (AVGAS), kerosine,
automotive diesel oil (ADO), industrial diesel oil (IDO),
marine fuel oil (MFO) and special high-octane fuels along with
LPG, paraffin, naphtha and low-sulfur waxy residue (LSWR).
Balikpapan I has two refinery units producing naphtha,
kerosine, gasoline and diesel and a high-vacuum unit producing
paraffin-oil distillate. Balikpapan II opened in 1983, supplies
AVTUR, AVGAS, kerosine, ADO, IDO, MFO and special high-octane
1. Balikpupan refinery had major
While the Balikpapan refinery has a rich history, aging
seals can add up to major leakage issues. The spiral-wound seal
designs in use at the refinery have been around about as long
as the original Balikpapan refinery (1950s); unfortunately,
these aging seals were not up to meeting modern demands.
The spiral wound gaskets would have a lifetime of
about six to 12 months before they would start leaking,
says David Hakim, a representative of PT Egamekinka Pratama, a
firm in Jakarta that specializes in pump engineering, sealing
devices and piping systems for the petroleum industry.
Then they would have to use online sealinga
frequent and expensive occurrence.
2. Evidence of leaks indicate failure
sealing gasket on this refinery unit.
Better sealing gasket.
Looking for ways to reduce maintenance and production costs
caused by the leaks and environmental problems from spills,
sealing consultants proposed replacing the spiral-wound gaskets
with a combination of a live-loading system and steel-trap
gaskets. The live-loading system consists of bolt-disk springs
that maintain the desired pressure despite mechanical shock,
pressure surges or thermal expansion and contraction. The
steel-trap design maintains a seal on high-pressure,
high-temperature lines, eliminating leaks and lowering
This action would improve reliability of the seals and avoid
replacing gaskets every six months or engaging in online
repairs. The Balikpapan refinery could use this approach to
achieve three or more years of leak-free operations.
3. Workers installing sealing gasket
Selecting the right sealing solution.
Choosing the right seal requires analyzing a combination of
factors including the materials making up the joint to be
sealed, operating temperature range, pressure class required
and the processing characteristics such as pH of the materials
that the seal is designed to keep in or out. One other factor
to consider when looking at the temperature is whether it is
constant, or if the equipment is frequently cycling thus
causing flange bolts to loosen over time. For high-pressure
applications in a refinery, maintenance crews have three basic
options: spiral wound, camprofile (or kammprofile) or
Spiral-wound seals have been around for
nearly a century and have justifiably earned a stable position
in the maintenance marketplace. Consisting
of alternate layers of a filler (typically graphite) and a
metal (generally high carbon or stainless steel) wound in
a spiral, they are more expensive than the sheet gaskets. But
they do not need as high of bolt loading since some of the
flange surface is in contact with the more compressible filler.
While lower, the bolt load is still significant and can lead to
warping and other problems associated with high bolt loads. In
addition, unless handled with care, these gaskets can come
apart during installation.
Camprofile. Like spiral wound, camprofile
gaskets use metal to support the softer sealing material. The
camprofile gaskets, however, use a solid metal core surrounded
by two layers of sealing material. The surface of the metal
core has a series of concentric grooves to hold the sealing
material in place. Camprofile gaskets can provide two
significant advantages over spiral wound design. First, the
metal support consists of a single piece rather than a thin
wound layer, which can unravel. Second, the sealing material
completely covers the surface of the metal ridges. Ideally,
even when the seal is compressed, the metal ridges do not come
in contact with the flange surfaces.
Unfortunately, real-world plant operating conditions are
less than ideal, which brings up the limitations for this
gasket-type design. The compressibility is limited to the
thickness of the sealant layer as it passes over the highest
point of the ridges, rather than the full thickness of the
sealant. Any further compression must come from the elasticity
of the metal. As a result, camprofile gaskets still require a
higher clamping force than if the full thickness of the sealant
can be compressed. In addition, since the metal backing is
rigid, vibration or water hammer eventually leads to
destruction of the soft graphite fibers. In severe services,
this gasket design can cause the metal ridges themselves to
break through and damage the flange surface.
Steel-traps seal design. To address these
shortfalls, steel-trap gaskets incorporate technology originally developed for
use on fighter aircraft. The seal base consists of a thin layer
of convoluted stainless steel with a 0.015-in. graphite layer
within the grooves on both sides. As a result, it is thinner
and more flexible than either the spiral-wound or camprofile
This design has several advantages over the older gaskets.
Since the metal backing is a single piece, it doesnt come
unwound like the spiral-wound gaskets. Most important, the
flexible nature of the metal base means that the metal itself
does not need to be compressed to achieve a seal. Instead, the
metal acts like a spring, keeping the graphite tight against
the flange. This greatly reduces the bolt load required, as
well as the need for retorquing and warping of the flange. The
flexibility also means that the gasket maintains its seal
despite shocks or thermal cycling. Since this design is more
pliable, the metal absorbs the energy of vibration and water
hammer, thus preserving the service life of the gasket.
While the intricacies of seal design may be fascinating,
what really matters most is not the type of seal used, but how
the joint performs in operation. The object is not to have the
most state-of-the-art gasket, but to ensure that failures do
not result in costly shutdowns, environmental or safety hazards or
add to maintenance costs. The bottom line
70 % of scheduled seal-replacement costs are labor
One unplanned shutdown or a single leak far exceeds
the few dollars spent on a seal.
4. Spiral-wound gaskets have several
disadvantages since a real compression seal
is not possible.
Camprofile-type seals were installed at troublesome joints
at the Balikpapan refinery in 2005. The first targets
were two heat-exchanger nozzles. A self-locator gasket made of
316LSS with a graphite filler, along with flange-bolt disk
springs, was selected.
A series of gasket replacements on other equipment began at
the refining complex. In March 2006, an
8-in. self-locating gasket was installed on a converting valve
from the power plants generator turbine and a 20-in. seal
(also 304LSS) on a check valve. The converting valve seal was
still working perfectly in May 2010. The check valve gasket was
reinstalled in May 2008 and remains in good condition.
In 2007, a 24-in. seal was installed in the steam-line block
valve and an 8-in. gasket was installed on a steam-line valve
from the turbine generator. Another 24-in. steel-trap gasket
was installed on turbine generator No. 5 in August 2008. All
were 304LSS with graphite filler. These gaskets are still in
operation and working well. In September 2010, additional
gaskets were installed on a steam line and reboiler heat
exchanger. Success of the gasket replacement solutions spread
to other regional refiners, including Chevron Petroleum
Indonesia, the countrys largest oil producer.
John Paterson is president of Sealing
Corp. of North Hollywood, California. The company
manufactures a line of self-energized metal gaskets
consisting of a corrugated metal carrier combined with
different soft sealing inserts (e.g., flexible
graphite, PTFE, mica or a combination thereof). These
gaskets operate at high temperatures (200°C to
1,200°C) and high pressures (400 bar).