Which of the following applications is unsuitable for a plug valve?

A plug valve is designed to provide a quick and tight shut-off in fluid flow applications, making it versatile in various settings. However, when it comes to high-pressure steam lines, this type of valve is generally considered unsuitable.

The reason for this lies in the operational characteristics of high-pressure steam systems. Steam can be aggressive and create conditions that lead to potential damage if not managed correctly. Plug valves can struggle with high temperatures and pressures because of their design, which may not handle the thermal expansion and the forces exerted adequately.

Additionally, high-pressure steam can cause erosion or wear on the valve components over time, potentially leading to leaks or failure. While they can work in certain low-pressure applications or for very controlled environments, for high-pressure steam applications, other valve types like globe or ball valves are typically favored, as they provide more secure sealing and better throttle control under extreme conditions.

In contrast, plug valves are suitable in low-pressure water lines, gas distribution systems, and hot oil lines, where their design can perform effectively without the adverse effects present in high-pressure steam applications.