Engineering valves for a specific application increases performance in challenging and complex chemical processes
Valves play a critical role in the chemical process industries (CPI). They help manage capital-intensive operations, protect equipment and support environmental compliance. Rather than relying on one-size-fits-all solutions, valve providers are developing application-specific designs and applying digital technologies to deliver more reliable performance in extreme conditions.
“For valves used in chemical processes, the challenge is the combination of highly aggressive media, pressure and temperature fluctuations, cavitation, emission requirements and maintenance under real plant conditions,” says Oliver Storbeck, president of Richter Group with Richter Chemie-Technik GmbH, a unit of IDEX Corp. (Kempen, Germany; www.richter-ct.com). “The goal is to select the valve that is best suited both technically and economically for the respective process conditions.”
He continues: “Operators are not looking for a generic ‘corrosion-resistant’ valve, but for a structurally robust system. What matters is that valves are reliable, easy to operate and maintain, and have a long service life.
“Additional requirements include high-quality lining with low permeation rates, leak-tight shut-off and long-term tightness to atmosphere, high flow capacity and precise control, minimal dead spaces, safe handling of pressure and temperature fluctuations and reproducible performance over many operating cycles,” Storbeck says.
Isaac White, marketing manager with Cashco (Ellsworth, Kan.; www.cashco.com), adds: “Reliability is a top priority because chemical processors want equipment that performs consistently to help prevent unplanned downtime, but beyond reliability, we see increasing interest in technologies that reduce operating costs, improve emission performance and support sustainability initiatives. In addition, end users are looking for solutions that provide tighter control, lower leakage rates, longer service life and easier maintenance, while helping their facilities operate more efficiently.”
Valve providers are responding to this user wish list with advanced valve technologies that are engineered to handle application-specific challenges.
Application-specific valves
“Poor valve selection may only become apparent after several operating and service cycles: a valve may be chemically resistant, yet still have a short service life if it is poorly designed for the operating conditions. This is why a valve provider’s experience with application engineering plays a key role for the end user,” Richter’s Storbeck says.
For example, Storbeck points to the shift away from “lining only” to functionally advanced, application-specific fluoropolymer solutions for previously challenging applications. “Particularly relevant here is conductive PFA with approximately 2% conductive pigment, which safely dissipates electrostatic discharge via the lining and the metallic housing. This achieves resistances of <109 Ω and discharge resistances of <106 Ω.
“Additionally, conductive PFA is now also available in an FDA-compliant form,” he continues. “This makes it possible for the first time to combine safety requirements from antistatic design with purity and compliance requirements from pharmaceutical, biotech and other sensitive or high-purity applications. At the same time, the transfer molding process ensures equal wall thickness and homogeneous wall structure, providing a quality advantage” (Figure 1).
FIGURE 1. Richter’s portfolio of fluoropolymer-lined valves provides application-specific solutions, including conductive PFA options that combine antistatic safety with FDA compliance for sensitive and high-purity applications
Cashco, too, is addressing application-specific challenges. “In storage-tank applications, for example, improper pressure management can result in excessive nitrogen consumption, unnecessary venting, product loss and increased operating costs. And, with the growing emphasis on emissions reduction and vapor management, chemical processors are taking a closer look at their storage-tank systems, venting strategies and nitrogen consumption to improve both environmental performance and operational efficiency,” says White.
In response, Cashco offers valves that maintain extremely tight pressure control while responding quickly to changing tank conditions to help reduce nitrogen consumption, minimize emissions and better protect storage tanks from pressure excursions.
The company’s Model 1078 is a pilot-operated valve that is specifically designed to reduce blanketing-gas losses on low-pressure storage tanks (Figure 2). It opens and closes automatically as required to maintain a closely controlled blanket pressure. The simple design increases reliability and lowers maintenance costs.
FIGURE 2. Cashco’s Model 1078 is a pilotoperated valve designed to reduce blanketing gas losses on low-pressure storage tanks. It opens and closes automatically as required to maintain a closely controlled blanket pressure
Ammonia and ethylene production also present specific challenges that are being addressed via valve development, says Sergio Zaghen, industry director – flow controls Europe, with Emerson Spain (Madrid, Spain; www.emerson.com). “In ammonia and ethylene service, valves must perform under high pressures and temperatures, while handling process media that cannot leak to the atmosphere,” he explains.
“The first-order concern is tight shutoff and fugitive emissions, particularly on regulated or environmentally sensitive gases. After that, it’s wear, because pressure fluctuations, thermal cycling and corrosive service steadily degrade a valve, and that’s what eventually shows up as a reliability problem or an unplanned outage,” says Zaghen. “With ammonia, the priority is holding reactor conditions steady and ensuring a relief device performs when it is called upon. With ethylene, the safety and regulatory bar is high, and the valve must hold specification through long runs between turnarounds. It returns to the same three factors every time: durability, emissions control and lifecycle performance. Those factors drive both specifying and maintenance.
“On ammonia units, the valves that matter sit in the synthesis loop, reactor pressure control and steam systems, and how tightly one controls their feeds directly into the catalyst conditions. Ethylene presents a different set of demands — cracking, separation and storage — with high pressures, wide temperature ranges and hydrocarbon service to manage,” he says.
“In both cases, one doesn’t reach those outcomes without the fundamentals: materials of construction, pressure rating, and trim matched to the actual service. Get that right and the unit will run safely, efficiently and in compliance,” Zaghen continues.
Standard valves will not suffice in these applications, he says. “High-performance valves are used where conventional designs meet their limits. And, with ammonia and ethylene, that means the high-pressure synthesis loops, severe-service control and critical isolation points must not leak or stick.”
In these applications, several products work together to provide a solution. The Fisher easy-e control valve is used for precise, reliable control and can be paired with a Fisher FIELDVUE digital valve controller for real-time diagnostics and improved operating accuracy. For isolation, Vanessa triple-offset valves provide tight shutoff and low maintenance across a wide temperature and pressure range. Anderson Greenwood pressure-relief valves cover overpressure protection and Bettis electric actuators handle automation with remote configuration and diagnostics.
“Individually, each does a defined job,” says Zaghen. “Taken together, they address what matters on an ammonia or ethylene unit: keeping it reliable and safe, holding emissions and energy use down and staying compliant as regulations tighten.”
Demanding applications
Technologies that can be adapted to the specific needs of applications where conventional valves fail are also being developed to help improve valve performance, increase lifespan and reduce ownership costs.
For example, to extend reliability in wear-intensive applications where valves are subject to erosion, corrosion or abrasion, Valmet (Vantaa, Finland; www.valmet.com) offers valves with its Neles WearBlock solution (Figure 3). “These unique metal matrix composites (MMC) help extend the effective operating life of valves where they once were subject to frequent failure,” says Lindsay Coutinho, senior manager of refining and chemicals with Valmet’s Flow Control business. “At the same time, these wear surface solutions are saving time and money by retaining optimal performance longer and extending service intervals considerably.”
FIGURE 3. Valmet valves with the Neles WearBlock solution offer unique metal matrix composites to help extend the effective operating life of valves where they once were subject to frequent failure
In addition to extending valve life and helping to avoid expensive unplanned shutdowns resulting from catastrophic valve failure, the extended periods between planned and scheduled service shutdowns contribute to the optimized total cost of ownership (TCO) of the Neles WearBlock solutions. “This wear-resistant design delivers a new level of durability, reliability, safety and long-term predictability,” says Coutinho.
The MMC combine the hardness of ceramics with the toughness of metals and improve on ceramics in terms of elimination of hydrothermal degradation, resistance to thermal shock and electrical conductivity, widening the application range of the company’s valves and helping contribute to profitability in both continuous and batch processes.
Modular control valves that can be adapted for demanding chemical applications, such as ARCA’s (Tönisvorst, Germany; www.arca-valve.com) ECOTROL series, provide a tailored solution. “ARCA’s strength lies in the ability to combine standardized modular valve platforms with highly customized engineered solutions for applications where conventional valve designs reach their limits,” says Christian Lambertz, head of international operations and sales with ARCA Regler GmbH.
“The ECOTROL platform combines flexibility, reliability and maintainability in a highly adaptable design,” he explains. “A wide range of trim configurations, body styles, materials, actuators and digital positioners allow the valve to be optimized for virtually any process conditions (Figure 4).
FIGURE 4. ARCA’s ECOTROL valves combine flexibility, reliability and maintainability in a highly adaptable design. A wide range of trim configurations, body styles, materials, actuators and digital positioners allow the valve to be optimized for virtually any process conditions
“A unique feature is ARCA’s patented clamp-seat system, which enables fast maintenance and trim replacement without special tools, reducing downtime and lifecycle costs,” says Lambertz.
The modular system provides tailor-made control solutions for steam, gas, oil and other fluid aggregate states. Various design elements and a trim designed precisely for the application’s flow conditions guarantee maximum efficiency, reliability and safety.
Digital solutions for reliability
In addition to developing application-specific solutions that allow valves to perform in challenging conditions, digital solutions further extend reliability.
“Digital valve controllers and diagnostics let plant personnel see how a valve is actually behaving, rather than discovering it at the next shutdown,” explains Emerson’s Zaghen. “Identifying a problem early turns reactive into proactive maintenance, saving money and avoiding unplanned shutdowns. Day-to-day, that same instrumentation helps plants operate closer to setpoint, resulting in steadier product quality, better efficiency and less variability. But the largest return is on maintenance. Good diagnostics help plants move from reactive to predictive maintenance, with each valve serviced at the right time to extend the life of the asset.”
For example, the Fisher FIELDVUE DVC7K instrument provides “Advice at the Device” via flexible connectivity and an easy-to-use interface that allows users to analyze data in real-time to evaluate performance and reliability, enabling operations to run closer to setpoint, improving product quality with more accurate control (Figure 5).
FIGURE 5. The graphical interface, LED status light and easy-to-use buttons of the Fisher FIELDVUE DVC7K digital valve controller help technicians quickly resolve problems
ARCA’s Lambertz adds that smart valve technologies have evolved from optional features to essential components of modern process plants. “Digital positioners, such as ARCAPRO and ARCASMART, provide significantly more information than traditional control systems. Beyond accurate positioning, they continuously monitor valve performance and operating conditions,” he says.
The benefits include improved control accuracy, faster commissioning, online diagnostics, predictive maintenance capabilities, reduced unplanned shutdowns, lower maintenance costs and increased process transparency, he notes.
“The trend toward digitalization is accelerating as operators seek to maximize plant availability while minimizing maintenance resources,” says Lambertz. “Smart valve technology transforms the control valve from a passive component into an active source of operational intelligence.”
And, when it comes to smart technologies, there are also benefits in the digital availability of product information, says Richter’s Storbeck. Richter has rolled out the digital nameplate as a standard feature across the entire portfolio. The implementation is based on laser-engraved QR code in combination with an encapsulated RFID tag.
“This enables product data, operating manuals, certificates, declarations of conformity and structured documents to be accessed directly at the valve,” explains Storbeck. “This system is chemically resistant, robust against damage and supports standards, such as IEC 61406, NAMUR NE 167 and VDI 2770. But for operators, this means faster identification, easier access to documentation and significantly more efficient service and maintenance.”
And, for valve monitoring, Valmet offers ValvesNow, a cloud-based valve-performance analysis tool that is integrated into the Valmet Customer Portal. It enables users to monitor valves in real time, receive automatic updates and access detailed cost analysis, all from one platform that is accessible from any device, anywhere.
ValvesNow collects diagnostic data from digital valve controllers daily and performs comprehensive fleet analysis weekly. It pinpoints the worst-performing devices and prioritizes valve issues, so owners can focus their maintenance efforts. In addition, the system analyzes valve performance across multiple categories — control performance, mechanical issues, operation style, working environment and device alarms — and ranks valves, making it possible to target equipment that needs attention.
“By prioritizing maintenance actions, ValvesNow helps maximize uptime and plant performance while optimizing resource use,” says Coutinho.
ARCA’s Lambertz summarizes: “By combining advanced valve technology, application expertise, digital solutions and customized engineering, operators can improve efficiency, reliability, sustainability and plant performance across industries.”
–Joy LePree