Hydrocarbon Processing - December 2021 - 60

Environment and Safety
analysis and mitigation steps commonly used
in reliability improvement processes are effective
at mitigating these risks beyond the scope
of traditional safety programs.
Static equipment: Distillation columns,
reboilers and condensers. Decreasing
failures not covered in regulatory inspections
reduces all safety concerns related to these
static vessels. For insulated vessels, insulation
inspections and repairs also decrease losses
throughout the system, consequently requiring
less thermal energy to maintain optimal
process conditions and reducing stress on supporting
systems. This can have an impact on steam, nitrogen,
air and electrical utilities. The National Insulation Institute estimates
that up to 43 MM metric t of CO2
emissions could be
reduced through insulation replacements and upgrades, equating
to nearly $4.8 B in energy savings.
Precision maintenance practices, such as detailed and proper
fastener selection and installation, also have a major impact
on the safety and reliability of these assets. Improperly installed
flanges have a significantly increased likelihood of experiencing
premature failures. For example, the flange that was improperly
torqued (starting at 180°) would likely experience a gasket failure
and leak to the atmosphere at 0° (FIG. 4). When these failures
happen, personnel safety is put at risk twice-when the
leak is present and when maintenance technicians repair it.
When high-priority or emergency jobs are executed, proper
planning and scheduling are often foregone. This leads to a higher
personnel safety risk due to fewer planned parts, materials
and tools. Even the most common type of industrial injuries-
slips, trips and falls-are at an increased risk when maintenance
technicians are traveling to and from job sites more frequently.
The U.S. Bureau of Labor Statistics estimates a non-fatal injury
rate of 4.2/100 full-time equivalent (FTE) per year (about
1 injury per 23,000 hr worked). Replacing poor installation and
break-in repair with a single precision task could effectively reduce
this to less than 3/100 FTE by simply reducing field callouts
(TABLE 2).
Rotating equipment: Pumps, motors and fans. Rotating
equipment (such as pumps, motors and cooling fans) in a distillation
system represent different and unique safety risks. Less
regulated than pressure vessels, the maintenance and inspection
activities on this equipment are most typically determined
by the owner's engineer. This often leads to subpar equipment
conditions and maintenance, where failures occur well below
the expected life of the equipment.
A coupling failure due to high vibration on the pump motor
can result in additional safety risks for all personnel in the area.
While vibration is inherent to these systems, excessive vibration
is most often a result of fasteners, lubrication, alignment or
balancing. These conditions that result in the coupling failure
can be mitigated proactively through proper installation and
maintenance practices and identified early with proper condition
monitoring methods.
Regarding bearing life extension, proper precision practices
can extend useful life by up to eight times. Fastener failures can
60 DECEMBER 2021 | HydrocarbonProcessing.com
FIG. 4. Improper torquing and
tension on a flange.
result in a sudden and violent dissipation of mechanical
energy. In addition to immediate safety
risks to personnel, this can result in severe cascade
failures of the system, potential releases
to the atmosphere and environmental hazards.
For example, in Norway in December 2020, a
failed steam shutdown valve caused a turbine to
overspeed, leading to a catastrophic failure and
fire. Failures to identify, classify and mitigate
critical equipment led to a lack of proper maintenance
procedures and practices. Luckily, only
severe financial losses were incurred on this operating
unit because of this catastrophic failure.
Electrical equipment: Motors and motor control centers.
Hazards often apply to the electrical equipment that supplies
the power to rotating machinery. In this case, electrical
energy represents the largest safety risk to personnel. Electrical
events (e.g., arc flashes) often have the potential to result in severe
injuries or fatalities.
Arc flash hazards, which are most dangerous at voltages
above 1,000 V, are often not covered under traditional relay
schemes. These events commonly occur when maintenance
technicians or operators are in the area operating the motor
circuit breaker and are switching circuits for normal operation.
A single failure in these motor control centers can lead
to cascade shutdowns and production stoppages, as the arc
flash energy is often high enough to bring adjacent equipment
offline. Preventing these events through routine cleaning and
testing not only improves worker safety, but also decreases
lifecycle costs by preventing catastrophic failures.
Routine cleanings, thermography and ultrasound monitoring
in motor control centers can prevent and identify the
conditions for fault events before personnel are put at risk. Industrial
Safety and Hygiene News estimated as many as 30,000
arc flash events per year, resulting in 7,000 injuries and 400
fatalities. In approximate terms, improving electrical testing,
maintenance and reliability practices by a minimal 5% across
the industry would prevent the following:
* 1,500 failures
* 300 plant shutdowns (up to 3,600 hr of downtime)
* 350 non-fatal injuries
* 20 fatalities.
If safety and shutdown systems are tested on an unplanned
basis, poorly maintained equipment can experience electrical
failures that can result in immediate dangers to plant personnel.
DREW
TROYER joined T.A. Cook in 2018 in the role as Principle.
He brings nearly 30 yr of experience and thought leadership in
the fields of manufacturing reliability engineering and physical
asset management. He is a Certified Reliability Engineer and an
MB. Mr. Troyer earned an MS degree in sustainability and
environmental management from Harvard University.
COLEMANN O'MALLEY is a Manager with T.A. Cook. He is a
reliability professional, with extensive experience in asset
management, risk assessment and implementation of reliability
projects in the oil and gas industry. As an electrical engineer
with several years of field experience in the refining and
chemicals industries, Mr. O'Malley is piloting the implementation
and development of digital solutions in asset management.
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Hydrocarbon Processing - December 2021

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