Reducing downtime, upping efficiency, and ensuring safety

A game-changing solution: how a uk refinery solved its esd valve woes

Partial stroke testing (PST) has been a mainstay of the oil and gas industry for years. In fact, it’s now the preferred way to test an emergency shutdown (ESD) valve’s reliability to do what it needs to – without actually closing it altogether.

Obviously, it’s a big step on from full stroke testing (FST), which often meant closing down a plant, or large sections of it, to carry out such a test. This was expensive, so actually led to more infrequent testing and, perhaps unsurprisingly, an increase in ESD valve failures. FST also offered no information or clues as to the health of the valve inside or any potential problems.

While today’s smart PST systems – whether mechanical or electronic – are a giant leap forward from FST, each does have drawbacks and limitations. For example, mechanical positioners  have limited  diagnostic capabilities, and aren’t compatible with all valves types. Plus, they’re tricky to install, commission and service. Meanwhile, electronic PST systems need additional kit to run and can be expensive. Often, they also need additional infrastructure or software changes to communicate with the systems.

So how can operators ensure those ESD valves that have been static or dormant for many months will, in an emergency, meet the moment? And all in a way that simplifies PSTs, ensures safety, and decreases downtime? Well, I think the best way to illustrate this is with an actual real-life example from one of HSP’s customers – a major UK refinery on the east coast of England.

This particular plant had identified a number of its emergency shut down valves (ESDs) were prone to sticking when required to operate on demand. In part, this was due to their infrequent use and the high temperatures and pressures involved in their application. A major concern of the operator was the inability of the valves to safely perform a PST, without the fear of insufficient voltage to re-energise the SOVs after performing a PST on them. Obviously, this raised potential safety concerns if there was a real emergency.

To solve the problem, the refinery operator would need a super-reliable system to monitor the power to the solenoid valve and prevent it shutting the valve down due to insufficient power to re-energise the SOV after testing. Whatever the solution, it had to be easy to install and work with the plant’s existing infrastructure. It also had to be operable locally, or through a DCS, using simple Pass/Fail testing. And it had to be able to be tested by Operators with no training or specialist devices.

As the principal distributor for IMI Maxseal in the UK, our fully trained technical experts knew precisely which product would not only solve the challenge, but also bring the customer new levels of efficiency, safety, and reassurance. The answer? The Maxseal ICO4-PST smart solenoid valve with fully integrated partial stroke testing and continuous valve condition monitoring capabilities. Thanks to its in-built diagnostic capabilities, it’s one of the safest devices available to conduct PSTs, with features that include electronics tests, voltage and air-pressure checks, in-built pressure transmitter tests, and positioner feedback.

Working together with IMI, we simplified the design of a PLC control cabinet to override the already simple PST procedures. So once a month, an Operator presses the button on the control cabinet to initiate a PST. If a green light comes on, the valve passes. If a red light comes on, the attempted PST is considered a fail and, thanks to the self-diagnostics performed by the IC04S-PST on the final elements, the valve can’t perform a PST test. The ‘fail’ is then escalated to a Technician for a full diagnostic inspection – using a handheld smart device or laptop – to identify the issue behind the aborted PST.

And because all valve activity is recorded on the SOV’s in-built memory card, a Technician can download and add all info to a data dossier of the valve’s lifetime performance. Even better, as PST tests can be performed locally via the control cabinet there’s no need to lay expensive comms cabling back to the DCS.

During a previous major shutdown, before the ICO4-PST was installed, the refinery had to remove and check several hundred valves. On inspection, only 30 or so needed replacing. A technician I spoke to remarked, “It’s a shame we didn’t have your solution available back then, because we’d have known exactly which valves weren’t working and replaced only the ones we needed to. The savings in downtime would have been huge”.