24-Month Field Report: Duplex Double-Eccentric Butterfly Valves in Refinery Catalytic Flue Gas Service

<h2>Project Background & Customer Pain Points</h2> <p>Flue gas piping on the waste-heat boiler of a catalytic cracking unit at a major coastal refinery faced severe conditions of <strong>high temperature, dust, and sulfur content</strong>. Previously used imported wafer butterfly valves suffered frequent seat wear and seal leakage, with an average service life of under 8 months. Each repair required more than 72 hours of downtime, and annual maintenance costs remained persistently high.</p> <h2>Selected Solution</h2> <p>After on-site surveys and condition analysis, the Handa Valve technical team delivered a customized <strong>2205 duplex stainless steel double-eccentric soft-seated butterfly valve</strong> solution:</p> <ul> <li><strong>Material upgrade:</strong> Body and disc in 2205 duplex steel, with significantly better chloride and H₂S corrosion resistance than 316L</li> <li><strong>Structural advantage:</strong> The double-eccentric design lifts the disc from the seat immediately upon opening, greatly reducing wear</li> <li><strong>Sealing:</strong> High-temperature RPTFE soft seat combined with a metal seat for dual protection</li> <li><strong>Batch replacement:</strong> 32 valves in DN300-DN600 replaced in phase one</li> </ul> <h2>24-Month Field Data</h2> <table> <tr><th>Metric</th><th>Previous Imported Valve</th><th>Handa Double-Eccentric Valve</th></tr> <tr><td>Average service life</td><td>&lt; 8 months</td><td>≥ 24 months</td></tr> <tr><td>Seal leakage</td><td>Seepage in mid-life</td><td>Zero leakage throughout</td></tr> <tr><td>Annual maintenance downtime</td><td>72+ hours</td><td>0 (maintenance-free)</td></tr> <tr><td>Procurement cost</td><td>Premium import pricing</td><td>~40% lower</td></tr> </table> <h2>Customer Feedback</h2> <blockquote>"In these 24 months, none of the 32 valves has leaked even once. Our waste-heat boiler inspection cycle has extended from twice a year to once every two years. Handa provided not only qualified products but also one-stop service from selection to after-sales." — Equipment Director of the refinery</blockquote> <h2>Key Takeaways</h2> <p>High-temperature flue gas service tests a valve in every dimension. Through the combination of <strong>material upgrade + structural innovation + customized service</strong>, Handa helped the customer leap from "frequent repairs" to "long-cycle maintenance-free" operation — a replicable model for valve localization in similar refinery units.</p>