• COVER STORY: VELAN •
in Severe Service Valves
Figure 1: A typical ebullated bed reactor for heavy-oil processing showing catalyst flow and valve positions.
Current Thermal Protection Solutions
Thermal shock in severe service valves has traditionally been mitigated using several methods, each with limitations. One common method is pre-heating valves with electric heat tracing, which maintains the valve at an elevated temperature to reduce thermal gradients. However, this approach is unreliable if the heat tracing system fails or is interrupted, leaving valves vulnerable to rapid temperature fluctuations.
While TBCs can be effective in some applications, they are prone to cracking and delamination under repeated thermal cycling, and their manufacturing and maintenance requirements can be challenging. Fully ceramic sleeves or refractory bricks, used in other high-temperature systems, are either too fragile or too bulky to be practical for ebullated bed valves.
Hexa-Shield™: AM Sleeve Solution Acknowledging the limitations of conventional insulation methods, Velan pursued an approach that could offer enhanced thermal protection without compromising valve operation, maintenance, or ease of installation. This drive for innovation resulted in the creation of the Hexa-Shield™, a patented additively manufactured sleeve that ' s designed to reliably shield valves under severe thermal cycling conditions, as illustrated in Figure 2. The figure shows the sleeve both as a standalone component and installed within the ball valve waterway, highlighting how it protects the valve from thermal stress.
Another strategy involves using solid sleeves— simple cylinders— that provide some insulation but are limited in effectiveness against severe thermal cycling. Thermal barrier coatings have also been employed to improve insulation. Typically, ceramic coatings are applied to the outer surface of sleeves to reduce heat transfer.
Figure 2. Hexa-Shield™ AM Sleeve:( Left) The sleeve as a standalone component.( Right) Installed within the ball valve waterway, illustrating its role in protecting the valve from thermal stress.
Valve World Americas | October 2025 | www. valve-world-americas. com 7