Molecular handsome switch valve
Thread Content
I’d like to ask discreetly: in LNG processes, is it better to use ball valves or eccentric butterfly valves for the molecular sieve switching valves? Let experts compare
Track ball valves are better, as there is almost no friction between them and the valve itself. Moreover, their sealing performance is superior to that of butterfly valves. Three-eccentric butterfly valves still experience some friction, and their sealing quality is not reliable over time. However, butterfly valves are cheaper. However, in China, most manufacturers of air separation equipment use butterfly valves in such molecular sieve sections, as track-type ball valves are too expensive. (There are few companies in China that can manufacture track-type ball valves well.)
OP: The flow capacity of eccentric butterfly valves is also lower than that of ball valves, and the pressure drop is greater as well. It seems that most LNG systems use ball valves, and those are imported ones
For air separation equipment used in LNG applications, from a cost-performance perspective, butterfly valves are definitely the choice – and those should be high-performance double-eccentric butterfly valves; triple-eccentric butterfly valves are not even considered. Orbital ball valves are not practical; such equipment would be extremely complex. For simple LNG process pipelines, ball valves on tracks can be recommended, but they are not mandatory. Judging from the title posted by the original poster, a double-eccentric butterfly valve should be used. Additionally, judging from the original poster’s title, people have different interpretations of it. Dear sailors, be careful when reading the questions. :)
The air used as a blanketing gas is merely intended to supply instrument air to the LNG plant. In the LNG processing process, there is a section dedicated to natural gas purification that requires cryogenic conditions; therefore, it is recommended to use ball valves on tracks.