Shell Side Pressure Drop
Shell Side Pressure Drop
(OP)
I've been charged with finding the pressure drop across a two pass shell side TEMA F heat exchanger with process vapor as the shell side fluid. Each pass is individually baffled with double segmental baffles. I've been trying to use Kern's equations for the pressure drop calculations but I have my doubts that these equations were meant for a 2 pass shell side.
As such, should I be considering each side as a separate heater when using Kern? Are there any methods out there for estimating pressure loss across an exchanger of this type?
Operating Pressure = 2.2 psia
Vapor Flow = 186,500 lb/hr
Condensing Area per pass 75% / 25%
Thanks in advance for any advice.
As such, should I be considering each side as a separate heater when using Kern? Are there any methods out there for estimating pressure loss across an exchanger of this type?
Operating Pressure = 2.2 psia
Vapor Flow = 186,500 lb/hr
Condensing Area per pass 75% / 25%
Thanks in advance for any advice.





RE: Shell Side Pressure Drop
For services in vacuum, hand calculations may not give you results with sufficient accuracy. Also, please note that significatn fraction of pressure drop may occur at the inlet/outlet nozzles. Why not use HTRI to simulate dP?
RE: Shell Side Pressure Drop
RE: Shell Side Pressure Drop
Unfortunately, I don't have acess to HTRI at the moment, otherwise I would gladly use it. Perhaps its time to convince the higher-ups to invest.
Any further advice would be greatly appreciated.
Thanks in advance.
RE: Shell Side Pressure Drop
To improve the accuracy you need a stream analysis method or a modified Bell-Delaware method. The Heat Exchanger Design Handbook has the lattter. A publication in the July 2004 Hydrocarbon Processing publication has an article that discusses shell-side pressure drop calculations.
In addition to calculating the cross flow bundle zones, end zones, baffle windows and nozzle pressure drops, the momentum loss needs to be calculated because of the vacuum.
RE: Shell Side Pressure Drop
RE: Shell Side Pressure Drop
RE: Shell Side Pressure Drop
Each pass is individually baffled. Since the longitudinal baffle is approximately 80% of the length of the shell, it divides the one shell into essentially two shells, or two heaters. Since Kern, and other methods only account for single pass shell sides, I was wondering if I should estimate pressure drop in each pass by calculating them as two separate heaters using flow information based on condensing in each pass? Also, is there a large factor of error in finding an equivalent diameter (as the two passes are obviously not round) and correlating the equations to a round tube in shell heater?
Thanks to all for your insight. I'm currently looking into the Bell Delaware Method and found that my company does have a copy of the Heat Exchanger Design Handbook, which has come in very handy.
Thanks in advance
RE: Shell Side Pressure Drop
Any ideas?
RE: Shell Side Pressure Drop
RE: Shell Side Pressure Drop