Saturated Steam

I believe when the pressure is reduced, it’s just the opposite occurs. Just keep in mind, that the energy content is reduced of the steam is also reduced.

theres a program called WASP (Water and Steam Properies) from Katmar Software. It’s a great program, I think it change its name.... I used it quite often early in my career to get the properties of steam at certain levels and pressures.

First of all I'll assume that PRV stands for pressure reducing valve, rather than pressure relief valve... Condensate traps are installed where the heat is being used to heat something, as the heat is transferred the condensate forms and must be drained from the system....Your steam transfer lines should be well insulated and have minimal heat loss...

https://www.armstronginternational.com/files/common/technical/870-EN.pdf

https://www.tlv.com/global/US/calculator/steam-table-pressure.html

Any time there is a possibility of overpressure in a system or vessel, there must be a safety relief valve...and it must be tested on a regular maintenance schedule...

In reducing the pressure and not the temperature of <...saturated steam...> the material goes from saturated to superheat, as any droplets within it will boil to vapour.

A1) Yes, at startup, and trapping the condensate prior to removal is always good practice.

A2) The forum cannot answer that as the specification for the downstream pipework and equipment cannot be seen from here. Bounce the question into the HazOp Study for the proposed change and see what answers come out.

The need for a PSV should already be covered on the supply side. However, a failure of the PRV could expose your lower rated piping after the PRV. It will require a PSV rated for the maximum available flow from your higher pressure supply. The cross tie pipe could actually limit the maximum flow, so over design of the pipe could lead you to having to purchase a higher capacity relief valve than necessary. It is also possible that you may have an existing PSV on the low side, but as PWSlack says, we can’t see that from here.