Selecting components that are inappropriate for their operating environment is a major cause of issues that can be extremely costly to rectify. As Olivier Beyerman, director sales and business development at Emerson explained during his presentation at Emerson Exchange EMEA 2024 in Düsseldorf, the right isolation valve design for deployment in renewable diesel production can have a major impact on unplanned downtime.
Renewable “green” diesel is an alternative fuel with interesting characteristics. It is made from 100% renewable sources, with feedstocks such as cooking oil, recycled animal fat or inedible corn oil. When used to power combustion motors it offers excellent performance and a low emission profile, especially in terms of NOx. However, when it comes to the production process, there are some downsides that make life extremely hard for isolation valves.
Variability in the feedstocks can be particularly challenging. Isolation valves deployed to control feedstocks must therefore have a design and functional capabilities to handle these variations to prevent production issues. Impurities and acidic gases in the raw materials are another potential problem. These can cause abrasion and corrosion to valve internals that compromises sealing integrity and causes premature valve failure. Viscous media and entrained solids in feedstocks can enter cavities and spring seals in traditional valve designs during cycling. This trapped media can solidify and impede valve actuation and eventually completely seize the valve.
Pressures up to ASME Class 2500 and temperatures up to 350˚C in reactors and processing units are not uncommon, which can push the limits of a standard valve. Flammable and hazardous media requires emergency isolation valves (EIUV) actuated assemblies to be firesafe to API 607 and SIL3-compliant to isolate the media in the event of a process upset.
Beyerman explained that it’s important to look beyond the initial installation costs of a valve, especially in challenging applications. Valves account for a significant amount of a refinery’s maintenance costs and are one of the main causes of unplanned shutdowns. It is estimated that approximately 62%* of the total costs of ownership occurs during the operating life of the valve.
Beyerman outlined what a superior valve for green diesel applications looks like. They should ensure ultra-tight, zero leakage, bi-directional sealing independent of process pressure or temperature. They should have no cavities where viscous media and entrained solids can accumulate, harden and prevent sealing. They will produce ultra-low fugitive emissions, designed and tested to ISO 15848-1 and with integral features such as high integrity joints. They will have proven tested performance, API 607 firesafe operation and be SIL 3 compliant. For enduring performance, materials must be optimized for cycle frequency, temperature range and process media resistance. Correct sizing is of course essential.
The AEV 2XC C-Ball valves from Emerson are designed for severe service applications including those in green diesel refineries.
Beyerman then highlighted the AEV ²XC C-Ball Valves from Emerson, which are uniquely engineered to meet severe service requirements typically found in renewable diesel refining. The AEV 2XC is the only true quarter turn valve with fixed seat that cannot be contaminated, and offers a wide range of seat materials, ball coatings and trunnion seals for difficult to handle processes. The valves utilize mechanical torque seating against a fixed seat that enables bi-directional zero leakage sealing, independent of process pressure or temperature. Non-rubbing quarter turn rotation with minimal friction throughout the rotation of the ball eliminates wear of the sealing elements. For any applications with a process fluid that will contaminate seat and spring areas, dramatic improvements in reliability can be realized due to the spring and cavity-free design. Although the design makes maintenance easier and quicker, zero cavities, no springs and frictionless rotation eliminates common failure modes, leading to increased availability and process uptime.
Beyerman remarked that when it comes to sustainability, the AEV 2XC C-Ball valves are doubly effective. Not only do they support the production of cleaner renewable fuels, but they also reduce emissions, with ISO 15848 certification allowing adopters to stay ahead of fugitive emissions regulations.
*InTech 2012 “Improve reliability with essential asset monitoring.”
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