Reduce Fugitive Emissions With the Right Ball Valve in Canadian Plants
by Thomas Webster, on Wed, Jan 05, 2022 @ 11:01 AM
In Canadian facilities, the ability to mitigate fugitive emissions depends on the condition of an operation’s ball valves. With approximately 60% of fugitive emissions coming from general industrial ball valves, proactive replacements and upgrades will reduce them, preventing a greenhouse gas from leaking into the atmosphere and any costly penalties that would arise as a result.
Ball valves are excellent options for shutoff and control due to their durability and reliability; these qualities are why ball valves are used in a number of processes in oil and gas capture and production. With their prevalence, it is important to consider the amount of fugitive emissions ball valves can prevent with timely upkeep to a system.
The Basics of Ball Valve Operation
The ball valve has a relatively simple operation which lends itself to multiple industry applications. The handle rotates an internal hollow ball which allows fluid flow when aligned with the inlet and outlet. Fewer moving parts help keep the valve performing optimally with a long service life and reduce repair or replacement challenges. Safety features are similar to other quarter-turn valves: visual confirmation of flow status is quickly relayed by the handle’s positioning (parallel to the flow for open, perpendicular for closed), and emergency shutoff remains expedited compared to more precise valves. The tradeoff for ease of use is a loss of precision in flow control; however, the vast benefits easily overshadow this drawback in a wide variety of processes. Notably, ball valves can be constructed of a wide variety of materials and variations for temperatures ranging from 0-230°C and pressures up to 3000 psig.
How API Standard 641 Covers Ball Valves’ Fugitive Emissions
In part, API Standard 641 governs the operation of quarter-turn valves, such as ball valves, in regards to acceptable levels of emissions over the service life of the valve. All stem seal materials must meet or exceed a maximum allowable leakage of 100 ppmv. To simulate field wear and creep, valves are subjected to 610 mechanical cycles and three thermal cycles. Temperatures will alternate between ambient and 260°C every 100 open-close cycles while pressure is held constant at 600 psi. Comparative static and dynamic measurements are taken both before and during cycling. To pass Standard 641 and receive BM class tightness certification, valves must emit less than 100 ppmv at any point while testing the valve stem (leakage at the body must be less than 50 ppmv for the duration of testing).
Ball Valve Styles and Designs
General varieties of ball valves include single body, three-piece body, and split body. Though valve function remains the same for the different iterations, other considerations such as operating conditions, service life, and repairability separate the styles into their respective niches. Ball valves with more pieces also compensate by allowing additional design options. Method of entry can further differentiate ball valves. Top entry valves are single-piece, which necessitates a more exacting design and manufacturing standards but allows for easier maintenance and faster access to the ball and trim of the valve. Meanwhile, side entry valves consist of a two- or three-piece assembly, which is easier to manufacture at the cost of increased maintenance time.
A further design consideration involves the attachment and lateral movement of the ball in the valve. For larger openings or high-pressure fluid environments, a trunnion anchors the ball to arrest lateral movement in working conditions. A floating ball design has no mechanical anchoring; instead, the ball is held in position by the compressive force of two elastomeric seats. Between the two styles, trunnion balls have a lower operating torque, facilitating smaller actuators (if necessary). Due to the inherent design of the ball valve, fluid can come to a rapid stop or encounter a change in direction that could induce hydraulic shock into the component. An actuator will allow for greater precision in the open-close cycle of the valve to protect the component and offer limited flow control operation.
Fight Fugitive Emissions with Ball Valves from Swagelok
Edmonton Valve & Fitting offers a wide range of low-leak ball valves from the Swagelok 40 and 40G series lines to suit multiple sizes and meet any operating conditions. For sizes up to 2 inches, the Swagelok 60 Series is available. All Swagelok 40 and 60 series ball valves are available with low emission certification per API Standard 641 to ensure fugitive emissions from ball valves are within regulation. Contact our Field Advisors to learn more about how our low-emission ball valves and additional products will help you curb fugitive emissions to keep your plant running smoothly and within regulation.