#106 Improved reliability and better emissions control during hydrofluoric alkylation processing.  Problem: At a Corpus Christi, Texas refinery, plant engineers were concerned about the overall performance of gate valves in their hydrofluoric alkylation processing system. They were seeking valving that would fulfill the following objectives: Improved operating reliability. Better control of fugitive emissions. Greater long-term economy  Evaluation A side-by-side comparison of gate valves and Tufline Sleeved Plug Valves was implemented. Following are five of the findings of this evaluation as well as features and benefits that influenced the final decision. The Tufline Sleeved Plug Valves were smaller and lighter than gate valves. Installation and service were easier. Pipe stress was reduced. The Tufline valves provided improved in-line sealing. For greater safety, Tufline valves are cavity-free. The Tufline valves were virtually maintenance-free, providing greater long-term reliability. These valves generally operate easily, even after being left open or closed for greatly extended periods of time. Even with much more frequent maintenance, gate valves have more operating problems. For greater fugitive emissions control, Tufline valves for HF alkylation service have a double stem seal. Both the top seals and in-line seals are easier to adjust. The lineal stem movement of the gate valve tended to open paths for emissions release.  Result: As a result of the side-by-side test, plant managers have made a major shift in valving selection, purchasing and installing a large number of Tufline sleeved plug valves. Both in terms of initial price and long-term cost-to- benefits ratio, Tufline was the clear choice. The processor also required some of the valves with RTJ (Ring Type Joint) flanges. As a plus, the Tufline Special Products Group was able to quickly and economically respond with valves of that design. Index of all performance report case histories.