Choosing Line Size & Pump Head

Abandon all hope, ye who enter here.

--Dante Alighieri

Simple. Hire a Process Engineer.

What a giveaway....

Why not a GiveAway....

sir,

Taking tapping from second user with increased line size of 4" can give velocity of 0.4 m/sec. does this work ? since reducing line size is adding head requirement for pump.

Secondly , putting two pumps one catering to first user & another catering to second user.

If you want to spend more with higher size piping, it's OK, less pressure loss. Velocity 2.5 m/s is maximum, lower are better. As the pressure requirement of two consumers are different, so putting two separate pump is also not a bad idea.

Play with P=ρgQH (H= pressure head+velocity head+static head+Head loss) & some moody diagram

I guess, have some reference book on you, try to read.

Dear Bhalchandra

Since caustic is corrosive, the recommended maximum velocity is 1.5 m/s. In order to cater for 12 or 13 m3/h, 2.5" is OK. For common header, either 3" or 3.5" is acceptable to cater for simultaneous peak demand of 25 m3/h.

Pressure of pump = 1.15(4 barg + line pressure drop + flow control valve pressure drop + differential elevation head).

Do the same for the first consumer with pressure = 0 barg. Select whichever is higher. Most likely, the 2nd consumer pressure requirement is greater.

Control valve pressure drop normally 20-30% of line drop.

Pipe arrangement - Pump into common header (3") and branch off to the respective consumers with 2.5' line. Flow control valve for 2nd consumer and probably level control valve for the first consumer for the gravity flow tank.

Two options for pump capacity:

1. Single pump - need to size for worst case scenario where peak demand is simultaneous (i.e 25 m3/h). 15 m3/h may not be inadequate capacity.

2. Two pumps (one standby) - this is common practice. 2 x 15 m3/h pumps each is adequate.

If I were you, I will choose the 2nd option.

Hope the above helps.

bhalchandra

If you need to ask sizing questions like this you do need a good process or piping and mechanical engineers to design this, else you can overlook design constraints and your back pocket design may backfire and cause an accident with injuries.