Oil and gas companies around the globe face the challenge of increasing production and delivering quality products while reducing resources and manufacturing costs. Process control has a financial impact and so reducing process variability is, therefore, a key factor in maximizing quality output and reducing costs. Comprehensive studies of control systems have shown that up to 80% of control loops have not performed satisfactorily in reducing process variability. In most instances, the control valve was found to be the major cause of the problem. Despite this, the impact of the flow control valve on dynamic performance is often overlooked.
Optimum flow control is imperative; choke and control valves are subject to a variety of technical phenomena and careful selection of the right control valve for each application is crucial.
Superior design features include the valve material, which should be resistant to the chemical composition of the flow medium. For example, discs and internals made of solid Tungsten Carbide, renowned for its erosion and cavitation resistant properties. Industrial diamond facings inserted on the discs have also produced some very good results under severe conditions. The sealing surface must not be in contact with the flowing medium to ensure seat tightness can be guaranteed for a longer period of time. The construction of the internals should ensure that the downstream of the back disc is abrasive resistant. This removes the majority of cavitation and erosive material from the sealing surfaces as well as from the valve body. The design of the internals must be able to absorb turbulence in the flow so that the outgoing flow is more laminar. Rotating choke disc valves are recommended for extremely severe applications.
Flow control valves are also optimized by using different shaped and sized throttling orifices in the rotating discs. This affects the Cv value of the valve and has a crucial impact on process control. The right valve size and trim must be chosen to match the process conditions.
For both new and existing applications, to ensure downtime is kept to an absolute minimum and additional costs are not incurred, flow control valves should ideally be engineered to fit with no modifications to existing pipework. This also ensures that any replacements can be made efficiently.
Ultimately, these design features coupled with repairable internals and easy maintenance maximize production output, lower life-cycle costs and extend the mean time between failures, providing an overall reduction in total cost of ownership.
Found in 1984, ASHUN has established a fine reputation worldwide. Our professional R & D team develops new products continuously to meet our customers’ needs. If you need more information about flow control valves or other valves, welcome to browse our website or contact with ASHUN directly!
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