Novel control valves meet gas plant’s strict noise regulations

Paul Boughton

A major gas processing plant being constructed in Norway needed novel control valve technology to meet stringent noise requirements

When complete, the gas processing plant currently being built at Nyhamna in Norway will treat gas from the Ormen Lange field. Located 120km off the north west coast of Norway, this field will consist of a number of seabed installations at depths of between 800 and 1100metres.

The Nyhamna plant has very strict noise requirements so finding appropriate control valves is an important issue (Fig.1). However, Emerson Process Management has just won a US$2m order to supply its Fisher control valves to the project.

The order includes all of the plant's control valves that have severe aerodynamic noise challenges, including export metering and gas to flare, in various sizes up to 20inches and pressure ratings up to ANSI2500.

To meet the plant’s noise requirements, many of the valves will be supplied with WhisperFlo low noise trims. These trims combine several noise reduction techniques including a unique passage shape, multistage pressure reduction, exit jet separation and an expansion area, all designed to minimise the acoustic energy radiated in the audible range.

Emerson says this solution represents the state-of-the-art for applications that demand the ultimate noise attenuation. A WhisperFlo cage with a correctly sized valve body can reduce noise levels by up to 40dBA compared to standard products.

Some of the valves will have special actuator systems for quick operation and all of the valves will be equipped with FIELDVUE instruments with advanced diagnostics capability.

These can be used to identify faults such as increased friction, incorrect seating or sealing forces and non-linearity or dynamic errors. This information can be accessed locally or remotely via the network, reducing the need to access difficult locations and minimising operator exposure to hazardous situations.

From the Nyhamna plant the gas will be exported through a pipeline system to the receiving facilities at Easington, UK. When it reaches full production, the field will meet 20percent of the UK demand for gas.

In a separate development, Emerson has also launched a new class of digital automation technology designed to improve plant operations and maintenance, including the prevention of unplanned shutdowns.

Smart Machinery Health Management (SMHE) extends the company's PlantWeb digital plant architecture by putting predictive diagnostics into intelligent transmitters that monitor and analyse rotating equipment health and deliver actionable information to operations and maintenance personnel.

Unplanned shutdowns

Unplanned production shutdowns are expensive, costing US$1m or more per day in some industries. Industry statistics point to mechanical failure as the cause of 43percent of plant incidents. Typical process plants such as in the oil and gas industry include 2500 machines, with 60 per cent being motor-pump combinations.

Motor-pumps are traditionally monitored only infrequently and repaired when they fail. A dramatic improvement in plant performance is enabled by the new CSI9210 Machinery Health Transmitter, the cornerstone of the SMHE. It delivers continuous actionable information about rotating equipment health directly into plant process control systems and asset management applications.

With this real-time information, plant operators are able to easily view rotating equipment status, recognise issues with machinery, and take actions to improve availability and plant performance.

According to John Rezabek, controls specialist for BP Chemicals in Lima, Ohio, USA: “The CSI9210 Machinery Health Transmitter can alert our operators in real time when equipment problems start to manifest. If a change in upstream head, volatility, or composition results in increased flashing or cavitation, they can make adjustments to eliminate the problem.”

The new device uses an embedded analysis engine to accurately identify potentially damaging conditions such as pump cavitation, bearing degradation, excessive synchronous vibration, and motor overloading and overheating.

Results are communicated using the FOUNDATION fieldbus protocol into process automation systems and AMS Suite Intelligent Device Manager predictive diagnostics software, giving users unprecedented real-time access to the true condition of their motor-pump assets.

With this real-time information, plant operators are able to easily view rotating equipment status, recognise issues with machinery, and take actions to improve availability and performance.

When used within the PlantWeb architecture, the CSI9210 Transmitter delivers analysis results in the form of PlantWeb Alerts, which categorise the warnings as 'advisory', 'maintenance', or ‘failed’. A specific Machinery Health Value is also given along with recommendations for any necessary actions. The assessment of machinery health generated by the CSI9210 Transmitter gives plant personnel a better understanding of the condition of monitored equipment and problems that may be developing.

According to Emerson, this knowledge empowers the practice of predictive maintenance, resulting in less equipment downtime, longer machine life, and lower maintenance costs.

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