Total Pressure Drop - The calculated pressure drop through the exchanger based on what conditions the exchanger is designed for (i.e. specified flows, densities, viscosities, etc.)
Allowable pressure drop - A specification provided by a process design engineer that is the maximum allowable...
One option you could consider, assuming your steam pressure allows it, is to use direct steam heating (i.e. a pick heater). This would eliminate your condensate recovery system, and would replace both heat exchangers with simpler and less costly direct steam heaters. You would be able to absorb...
My understanding is that if the PSV lifts you will need to drop below the blowdown for the valve to reseat. Even if the valve does not fully lift.
If you are operating at 90% of set pressure with a conventional valve and the PSV lifts, you are correct that you may not get the PSV to reseat...
API 520 Pt II has the following guidance on check valves.
Check valves shall not be installed in PRD inlet or outlet lines since these devices are normally closed and the check valve can become stuck in the closed position or fail in a manner causing an obstruction in the PRD path.
I...
