Improperly installed valves at petrochemical plants and refineries are causing millions of dollars in losses.
Controlling the flow of gases and liquids in downstream processes is of paramount importance to plant operators especially where millions of dollars in potential savings are at stake.
Valves are technically pipe fittings, but are usually discussed as a separate category. In an open valve, fluid flows in a direction from a higher pressure to lower pressure environment.
In a refinery environment where the presence of highly corrosive materials, high pressure and high temperatures are standard, valves play a critical role. As well as being fundamental to the safe operation of the plant, they have a direct impact on productivity.
“Reliable valves are the key to smooth, efficient operations. Valves are used widely across the plant, from applications such as pressure relief, isolation and emergency shutdown, to areas such as pollution management,” Andy Hoxley, marketing manager, Tyco Valves & Controls Middle East.
“Process plants like a refinery or a petrochemical plant contain hundreds or even thousands of control loops all networked together to produce a product.
A control valve is a critical part of these control loops and is the most common final control element in these process plants,” says Jose Mathew, sales director for fisher valves at Emerson Process Management Middle East & Africa.
“Control valves regulate flowing fluids such as gas, steam, water or chemical compounds and keep the process pressure, flow, level, or temperature as close as possible to the desired set point to ensure the quality of the end product,” he adds.
Within a typical downstream plant, whether it is a petrochemical, fertiliser or a refinery, the most common type of valves used in these plants are the gate, globe, and check valves from forged or cast steel.
“The main difference of the valves used in petrochemical plants is the material used in the fabrication of valves.
Normally the valves used in the petrochemical Industry need to be made from high corrosion resistant materials,” says Abdul Shahir, sales manager at ValveTech, a stockist and distributor of industrial valves in the Gulf region.
Valves used in refinery applications are designed operate under high pressure and high temperatures. During the refining process, valves handle a variety of substances, from viscous, semi-solid, to thin liquids, many of which are highly corrosive.
“As a result, valves for these applications are specified and manufactured from materials appropriate to the media. The valves most frequently found in refineries include ball, butterfly, control, gate, globe, check, pressure relief and rotary process valves,” says Hoxley.
“One example is the Vanessa triple offset valve. Suitable for the most severe service applications, this valve is found in refineries around the globe, due to its reliability in high pressure, high temperature environments, and its availability in materials appropriate to a variety of process conditions,” he explains.
Like all equipment used in the plant, valves are subject to failure that could prove very costly if not repaired promptly. “Failure of control valves most commonly results from improper sizing, selection, application, installation, or maintenance. If a control valve is properly sized and selected for its particular application the vast majority of failures can be avoided,” says Mathew.
The improper installation of valves cause the majority of problems. “Failures are most likely to be caused by a wrongly specified valve at the outset, or the lack of maintenance once in service. Failure through incorrect specification can be prevented by working with specialists from the start of the project,” says Hoxley.
“For example, Tyco works with customers to ensure that it supplies valves that exceed the specified operating conditions, and that the materials and trim are appropriate for the environment,” Hoxley adds.
In addition to the poor installation, leakage is one of the major issues. “The most common failures in a valve are leaking through seals (gaskets, pickings and O-Rings) and leaking through the casting,” says Shahir.
“When a leakage appears in the seals, this can be fixed in days or hours depending on the type of valves. Walworth after-sales service in the region will support the customer in all stages,” he explains.
Some failures are hard to fix, and time consuming. “In case of leakage through castings, fixing can take weeks, perhaps months or even it may have no way to fix it,” he notes.
The ability of a customer to speak with locally-based experts who understand the customer’s needs and are closely connected to the valve factory can make a critical difference when specifying a control valve.
“Local support from factory-based personnel helps greatly with installation and maintenance,” says Mathew.
Buying tips
With today’s advanced products and technologies the old days of reviewing a bid and making decisions on the lowest purchase price are far in the past.
Procurement managers nowadays are required to be more strategic in their planning and review of the products, services, and relationships under their care.
“Today’s procurement managers are expected to deliver the best products, and lowest total cost to their organisation that is possible. This is just as true for control valves as it is for many other highly engineered products,” says Mathew.
“They must not only rely on their own internal experts but they must also develop strategic relationships with suppliers that bring more expertise and capabilities to their organisation than in the past or than available internally.
Also, they should seek out companies who bring more than just products,” he explains. When specifying new valves, it is also vital to look beyond the purchase price say the experts.
“It is very important to consider the whole lifecycle cost of the equipment, taking into account the cost of operating and maintaining the valve throughout its useful life,” says Hoxley.
“From design and specification to commissioning and after sales service, as the world’s largest supplier of valves Tyco has the experience and full range of valves for every refinery application,” he explains.
Today’s suppliers must not only offer a broad range of thoroughly tested and proven products; they must offer the business acumen needed to properly apply these products to meet a procurement manager’s business objectives.
“By ensuring that a local maintenance team is available to provide a planned maintenance schedule, procurement managers can ensure that every valve maximises its capability throughout its lifecycle,” concludes Hoxley.
