At what point in an oil & gas project should we start thinking about pipeline maintenance? Bryan Voytilla of SPX FLOW argues that good maintenance begins with good product design and explains how their valves, pumps and closures portfolio can contribute to operational excellence, from specification through to condition monitoring.
Pipeline operation and maintenance throws up some unique challenges, particularly in the oil and gas sector. Critical equipment like pumps and valves must be resilient enough to withstand varied environmental conditions such as the salt-laden atmospheres on exploration platforms, or climates on land ranging from hot desert to icy tundra.
The fact that the products being transported are by their nature harsh and corrosive adds another dimension to maintenance considerations. Robust design, material specification and build quality is key to ensuring that pumps, valves and closures are robust and reliable from the outset, thereby optimising pipeline productivity and minimising downtime.
While critical equipment for pipeline applications may command a premium, the fact that its superior design and quality can withstand the operational challenges for longer periods means that capital cost is offset by the savings on routine maintenance or unanticipated outages.
Although the basic operational principles of valves and pumps remain unchanged, designers and manufacturers are constantly seeking ways of making them more efficient, flexible, reliable and easy to maintain. As a multi-industry manufacturer, SPX FLOW provides creative solutions that can help improve operational and maintenance efficiency in all phases of oil, gas and biofuel production: from exploration, extraction and processing to transport and storage.
Better by design
The M&J Valve Model M-303 is a good illustration of how better design can contribute positively to improve operation and reduce maintenance. Manufactured and tested to API-6D, the M-303 is an advanced slab gate valve that uses the natural force of line pressure to obtain a dynamically tight downstream seal in high-pressure differential applications. Low-pressure sealing is accomplished with coil springs that energize the seat pushing it against the gate. It is available in line sizes 2" - 84", class 150-2500.
Ease of maintenance and versatility make the M303 the leading gate valve in the industry. A two-piece stem/common yoke simplifies operator mounting and conversions and allows different materials to be used in wetted areas while standard material is used for stem threads. Combined with the bolted packing retainer, the two-piece stem allows quick operator and extension changes in the field with the valve under pressure. For valves with ribs, a new rib system has been developed to make painting and coating easier.
The function of some valves is to prevent damage to other critical plant. Surge relief valves on pipelines are a prime example. Pressure surges can be generated by anything that causes the liquid velocity in a line to change quickly and can cause flange separation, leaks or major piping damage. Offering very quick response times and high flow capacity, the DANFLO® surge control valve is ideally suited to surge-control applications. Moreover, its high flow coefficients usually mean fewer and/or smaller size valves are necessary to meet user requirements, reducing maintenance. In addition, problems such as nitrogen loss through permeable elements, valve failure due to tube splits caused by contaminant flow, or tubes taking a permanent set which prevents valve operation are all eliminated with the DANFLO design.
Pump specifications can be unique to the application, which can lead to unnecessarily complex design that can impact on maintenance. To avoid unnecessary complexity, ClydeUnion Pumps takes a collaborative approach with customers and suppliers to ensure the optimum engineered solution is achieved. Its CUP-BB5 range is a case in point. It encompasses radially split, diffuser type multi-stage pumps specifically designed for the high pressure and high speed service needs of the market. With two main variants of in-line impellers (CUP-BB5HPi) or back-to-back impeller arrangement (CUP-BB5HPb) the units are bespoke, engineered-to-order solutions, fully compliant with current API 610 & API 682 requirements and customer specifications.
A stiff rotor design, based on achieving maximum sustainable hydraulic efficiency, extends mean time between overhauls and reliability in operation. The resulting high critical speed margins and low static deflections reduce internal wear and increase reliability. The simple construction of the CUP-BB5HP pump also contributes to its ease of maintenance: a complete rotor change-out can be completed in under eight hours. These highly successful machines are used extensively throughout the oil and gas, exploration, production, transportation and refining sectors.
Closure applications can vary enormously, as these essential products are used to enable easy access to pipelines when equipment such as pig launchers, receivers, filters, separators and others require maintenance. Without closures, extensive man-hours would be required to gain safe access to pipelines, and maintenance expenses would be even more significant to company balance sheets.
Pipelines increasingly have their own unique closure requirements: sometimes because of the way that they run over the geographical layout of the landscape, or because of the nature of the substances that they transport. However, the US market has always favoured standardised products that have pre-ordained markers of high functionality and low maintenance. Standardisation has a number of benefits, including shorter delivery times, fewer parts to hold in stock and less complex training requirements. SPX FLOW now stocks standardised closures ‘on the shelves’ in the US, which has resulted in a 50 per cent reduction in lead-in times for its patented and world-renowned GD Bandlock 2 Closure technology for US clients.
Pipelines are notoriously difficult to access, so associated equipment needs to be designed with this in mind. For example, confined installation space and restricted access for maintenance are becoming increasingly important factors as oil and gas operators seek to optimise industrial real estate.
In response, SPX FLOW has introduced the CombiProLine OH3 vertical pump, which offers a space saving of up to 70 per cent when compared to the equivalent OH2 horizontal pump. By eliminating the need for a baseplate, the CombiProLine is easier to install than horizontal pumps and offers a weight advantage that makes it particularly attractive for platform installations. Part of SPX FLOW’s Johnson Pump Combipro family of heavy duty centrifugal pumps, the OH3 is designed and built to deliver long life and reliability in the harshest environments, and meets the requirements of API 610 and ISO 13709.
Careful identification and monitoring of the factors that may impact each pipeline system is key to maintaining a highly reliable system. This does not just apply to the equipment: it extends to the people who work on the system, live around it, or could be impacted by any interruption. Pipeline integrity is crucial for the safety of everyone, minimising disruption and unwanted downtime.
Any pipeline management system must provide 24/7 control and real time performance monitoring. This not only requires best in class equipment, but also top personnel to maintain the system.
The unique linear nature of pipeline assets means that maintenance is often required in multiple locations, at different times. Regulatory authorities will also define certain sensitive geographic areas called ‘High Consequence Areas’ that are based on population and environmental impact, which require more frequent monitoring. These factors and others mean that pipeline management requirements fluctuate enormously, and can make retaining a dedicated inhouse maintenance resource impractical.
Being able to draw upon an external resource gives much greater flexibility to the workforce and means they can be deployed when and where required. SPX FLOW’s Aftermarket group works with customers to plan and implement maintenance programmes to extend the life of pipelines.
Typical customers include major gas and liquid hydrocarbon pipeline transmission companies which own large diameter, high pressure pipelines that are regulated by various government agencies. Preventive maintenance programmes include regulatory agency-required equipment inspections, annual block valve flushing and equipment lubrication. Customer-scheduled actions driven by risk assessments include repairs, maintenance or upgrades on ESD, line-break and over-pressure protection equipment.
In addition to proactive pipeline integrity programmes, there is a growing demand from regulatory authorities for pipeline operators to install improved technologies to guard against line breaks, over-pressure protection and other potential failure mechanisms. Pipeline operators are therefore increasingly reliant upon digital instrumentation and automation to monitor pipeline condition and proactively predict maintenance requirements before they can cause an issue.
However, in particularly remote locations this level of automation is not always possible. In such circumstances, SPX FLOW can supply pneumatic systems to safeguard and manage pipeline systems to achieve similar results to automated systems. Where there is no connection available to the electricity grid, these systems can connect to wind or solar-powered satellite communication equipment to convey their status and allow the owner to change operating parameters remotely.
Pipeline maintenance is not an activity that only starts once the project is operational. There are major gains to be made by selecting high quality, high specification critical equipment such as valves, pumps and closures at the outset as this will increase reliability and reduce maintenance requirements. In addition, specialist manufacturers are building in specific features that support the maintenance needs of the oil and gas pipeline sector: including valves and closures with fewer parts.
As further new pipeline infrastructure is installed, and as the operating lifespan of existing pipeline infrastructure continues to be extended, the pipeline service market must grow to respond and meet demand. There is a greater requirement than ever for condition monitoring and preventive maintenance, which cannot be met entirely by existing automation. Despite recognising the integral role of new technologies, there will always be a need for non-digital approaches to pipeline management. Physical on-site inspections remain necessary: partly because they are required by certain regulatory authorities, which make it mandatory for most valves to be visually inspected.
Deep expertise in aftermarket servicing remains critical for finding new solutions to changing needs across pipeline operators. As a group, SPX FLOW is uniquely placed to develop and deliver the product innovations and aftermarket services that the oil and gas pipeline sector requires.
Images and captions
ClydeUnion Pumps CUP-BB5 range of radially split, diffuser type multi-stage pumps offer bespoke, engineered-to-order solutions to meet customer specifications.
The CombiProLine OH3 vertical pump offers a space savings of up to 70 percent when compared to the equivalent OH2 horizontal pump.
Alison Jones, PUBLITEK
Tel: 01582 390980