Hydrocarbon Processing - September 2022 - 123

History of the HPI-The 2000s
ValvTechnologies
Improve Operations by Considering
Total Cost of Ownership for Isolation Valves
When planning new projects and evaluating
unit maintenance costs, it is best practice
to consider equipment as an investment and
calculate the total cost of ownership to select
the best equipment. Calculating the total cost
of ownership considers equipment acquisition,
maintenance, repair, and replacement costs
during a specified time. Calculating the total
cost of valve ownership, specifically for isolation
valves, can help eliminate unscheduled
shutdowns due to valve failures that can risk
safety or damage equipment.
DEFINING RISKS
Define isolation valve " failures " and their
risks. Each unit may have different recurrent
issues that can cause big problems. Some of
those may be leaks through the stem that create
fugitive emissions, internal leaks through
the seats (of a closed valve) that degrade efficiency,
or valve stroke issues that can have
catastrophic consequences.
COSTS TO CONSIDER
To evaluate the total cost of ownership,
define time range, identify the valves to analyze,
and calculate total maintenance costs.
1. Define the time range
To comprehensively analyze the economics
of a valve purchase, we recommend using
two operating windows or maintenance cycles
(scheduled plant shutdowns).
2. Identify the valves to analyze
We recommend analyzing no more than
four valves for simplicity. Choose valves that
have some relationship to each other. This
enables understanding their operational effect
on the plant.
3. Calculate total maintenance costs
(purchase, install, maintain, repair,
replace)
Include the valves' initial purchase price,
installation cost, preventive maintenance
costs, repair costs (multiplied by the number
of repairs expected during the valves' operational
life), and replacement costs (multiplied
by the number of replacements expected during
the identified period).
To fully evaluate a valve purchase, consider
the costs of valve failures, such as unscheduled
shutdown and efficiency-related costs.
SPONSORED CONTENT
A valve failure can cause an unscheduled
shutdown if it creates a safety risk to people
or the environment or damages equipment.
Determine whether the process must
be stopped completely to replace the valve,
reducing production or if it is a batch process
that requires an extended cycle time due to the
intervention. To quantify the costs, start with
the per-day cost of a unit shutdown; divide it
into an hourly cost; then multiply by the number
of hours needed to repair or replace the valve.
Efficiency-related cost analysis is one of the
most complex because it requires high-level
process knowledge. Consider increased fuel
consumption, lengthened operating cycles for
batch applications, and increased downtime
due to leaking valves.
If an isolation valve of a multi-train coking
system leaks, the pressure available for the cutting
water system declines, increasing the time
required to decoke the reactors. This longer coking/decoking
cycle shrinks overall production.
In refinery fractionator-tower bottoms systems
with two pumps, one pump must be periodically
shut down at a time for maintenance.
In this case, the failure of an isolation valve will
considerably escalate downtime.
EXAMPLE ANALYSIS
The total cost of ownership for a catalyst
withdrawal application in an FCC unit using
the time range of 10 years or two operational
windows.
Solution 1
* Two gate valves
* Operational window: five years
* Shutdown cost: $250K US per day
* Replace Valve 1 annually
* Replace Valve 2 every two to three years
* Time required to change Valve 1:
one hour
* Time required to change Valve 2:
36 hours
* Valves 1 and 2 begin to leak after
six months of operation
* Catalyst loss per day: 2lb/day average
during six months
Solution 2
* Two ValvTechnologies' zero leakage
ball valves for isolation and a gate valve
for throttling
ValvTechnologies' custom purge
configuration removes and displaces hot
bitumen, eliminating coke fouling and
increasing the mean time between repairs
reducing the total cost of ownership.
* Operational window: five years.
* Shutdown cost: $250K US per day
* Replace Gate Valve every two years
* Replace ValvTechnologies' Valve 1
every five years
* Replace ValvTechnologies' Valve 2
every 10 years
* Time required to change Gate Valve:
one hour
* Time required to change Valves 1
and 2: zero because it is performed
at the scheduled shutdowns
* No catalyst loss
The total cost of ownership for Solution
2 is just 25% of Solution 1, despite its higher
initial investment. The difference is over the ten
years, costs for unscheduled shutdowns and
catalyst losses have been eliminated, saving
both cost and headache.
Similar analysis has shown comparable
results in a variety of processes. Contact
ValvTechnologies to discuss your project and
custom solutions.
CONTACT INFORMATION
Address: 5904 Bingle Rd, Houston TX 77092
Phone: +1 713-860-0400
Fax: +1 713-860-0499
Email: info@valv.com
Website: www.valv.com
Hydrocarbon Processing's Centennial Anniversary | SEPTEMBER 2022 123
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Hydrocarbon Processing - September 2022

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