Hydrocarbon Processing - October 2021 - 88

Valves, Pumps and Turbomachinery
valves are online when the system is functioning normally.
If either solenoid valve requires maintenance, users can engage
the maintenance bypass mode and quickly fix the issue
without interrupting the process. When the solenoid valve is
repaired, users can disengage maintenance bypass mode and
resume normal operation.
The RCS 2oo3D architecture uses an additional solenoid
valve, along with the maintenance bypass valve. Using the
same principle as the 2oo2D architecture, if a solenoid valve
requires maintenance, users can go into maintenance bypass
mode without interrupting the process and quickly fix the issue.
Both the 2oo2D and 2oo3D architectures provide high reliability
and safety to mitigate spurious or nuisance trips, maintain
process uptime and keep workers and equipment safe.
FIG. 2. The RCS pilot valve systemb
achieves a higher level of process
safety and reliability by using redundant, fault-tolerant architectures,
high diagnostic coverage and automated testing.
switches provide are essential for detecting issues before it is
too late to prevent damage, preventive maintenance is just as
important. Solenoid valves require testing-and maintenance,
when necessary-to prevent stiction. Reliable all-in-one solutions
exist that provide diagnostic feedback and keep systems
online, even when solenoid valves are being tested or serviced.
A pilot valve system features redundant architectures that
provide extremely reliable diagnostic coverage, a higher level
of process safety and online preventive maintenance. With a
2oo2D or 2oo3D architecture, the redundant control system
(RCS) combines pressure switches, redundant SOVs and a
maintenance bypass in one package (FIG. 2). By using a redundant,
fault-tolerant architecture, this pilot valve system has no
single point of failure that could lead to an unplanned closure
of the process valve, which greatly reduces spurious trip rates.
The RCS provides automated online testing with no bypassing
required, which allows users to detect potentially
dangerous failures prior to shutdown demand. This reduces
the Probability of Failure on Demand average (PFDavg) and
enables the RCS to be certified as Safety Integrated Level 3
(SIL3) capable. The completely automated, online solenoid
valve test features continuous monitoring and diagnostic feedback
from pressure switches, and can be set up to run daily,
weekly or monthly, reducing maintenance costs and ensuring
that functional solenoid valve testing is performed as scheduled.
Because testing is performed online with no bypassing
required, safety availability is maintained.
Preventive maintenance that eliminates downtime.
Preventive maintenance, using diagnostic feedback, helps to
increase safety, reliability and operational efficiency by minimizing
spurious trips and keeping the process running. However,
maintenance of any kind can be its own issue if it takes
too long. To avoid extensive periods of downtime, maintenance
must be quick and easy.
With three components (two solenoid valves and a maintenance
bypass valve), the RCS 2oo2D architecture features a
maintenance bypass that allows for online maintenance without
process interruption. In this architecture, both solenoid
88 OCTOBER 2021 | HydrocarbonProcessing.com
Increased reliability, availability and safety. Diagnostic
and preventive maintenance solutions provide users the ability
to continually monitor solenoid valve positions from the
control room. When users in the control room receive an alert
that there is an issue (such as a spurious trip), they can address
it and perform maintenance, as needed. The continual feedback
that these solutions provide allows facilities to address
any minor issues-through preventive maintenance-before
they can turn into major issues and potential shutdowns.
While dependable, on-demand shutdown solutions are
critical for increasing reliability and allowing easy maintenance,
it is also important to partner with a supplier that has a
wide range of products to meet unique application needs and
that can also provide strong technical support.
Working with a partner that provides complete diagnostic
and preventive maintenance solutions-from the device level
to the control/DCS level, with analytics and software-can be
advantageous at all levels to help refineries and chemical plants
improve their operation efficiency and overall performance.
Diagnostic capabilities and preventive maintenance can
help refineries and chemical plants increase their safety and
reliability, reduce maintenance time and improve their overall
operational certainty. Feedback from pressure sensors, pressure
switches and switch boxes are crucial, allowing personnel in the
control room to monitor equipment and perform preventive
maintenance, as needed. All-in-one solutions with redundant,
fault-tolerant architectures make it possible to perform online
testing and maintenance without interrupting the process.
Integrating dependable, on-demand shutdown solutions
backed by a strong partner revolutionizes maintenance, increases
reliability,
NOTES
a
Emerson's TopWorx GO Switch
b Emerson's ASCO 2oo2D and 2oo3D RCS pilot valve systems
GABE BOLTNIEW is a Product Marketing Manager at
Emerson, focused on the hydrocarbon industry. He earned
a degree in business administration from William Jewell
College, and an MBA degree in marketing and international
business from Seton Hall University.
significantly minimizes downtime and
ensures that critical valves function when they are needed
the most.
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Hydrocarbon Processing - October 2021

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