Ok, I managed to get a little empirical data on the system and I think I resolved my own problem, though not in a satisfying manner. X1, X2, and the pressure out of the feed pump will all be equal. I can use the feed pump to boost that pressure, but it will also boost the back pressure to the...
The feed pump will operate with a VFD and the re-circulation pump will use a motor starter. The 68 GPM filtrate stream will have a manual throttling valve as well as the 7 GPM concentrate stream. There are no other valves within the loop shown.
The pump suction will be the path of least resistance for the injection stream so the flow should go that direction as opposed to back flowing (I think). So, I believe it should work. The pump discharge pressure is the result of the pump. I don't understand your pump discharge comment.
I'm trying to size a pump, but my issue is not being able to determining the feed pressure of said pump. I have a re circulation loop of 1,408 GPM. I am injecting 75 GPM into the loop at a higher pressure than the return loop pressure. Ultimately, the goal is to reduce the boost pressure...
