Is Mechanical Vapor Compression a Boiler?

[Matt Janssen]

I'm working on a Mechanical Vapor Compressor (reciprocating steam compressor).



There are two operating scenarios:



1) Taking a steam flow and compressing it up to a higher pressure and temperature with water-spray desuperheating before the compressor.



2) Evaporating hot water below 212F/100C atmospheric and compressing it to pressurized steam.



What is your opinion on if a Mechanical Vapor Compressor working in an open cycle with water/steam as a working fluid where evaporation is taking place is a boiler subject to ASME Code?

 

[JStephen]

I would say not, but you'd need to check the wording in the code itself.
I know, for example, that in Section VIII, that pumps, hydraulic cylinders, piping, etc., is all excluded from the scope of Section VIII.

 

[Matt Janssen]

The question is, is a cylinder with a movable plug controlled by mechanical means (a piston) a vessel? The Preamble of Section I states, "A pressure vessel in which steam is generated by the application of heat resulting from the combustion of fuel (solid, liquid, or gaseous) or from solar radiation shall be classed as a fired steam boiler." Theoretically, a MVC could be powered by a variety of means, including a waterwheel prime mover, which would create heat and pressure from the work of compression.