Dear experts, i'm doing a rating design for a existing heat exchanger.
It's a Finned tube Air Heater, from the Original design:
Outside: Air flow with 123231 kg/h, inlet temp = 23.2 C; Op.pressure = 5.98 kPa(g)=> Outlet temp = 115 C
Tubeside: Saturated steam: 5710 kg/h, 140 C, 260 kPa(g), outlet temp = 140 C
That is the design. Actually we use Air flow only 88000 kg/h (inlet tem = 35 C, outlet = 87C), the steam consumption is around 1900 kg/h and condensate outlet temp = 38-42C, the steam inlet nozzle 8", so the control valve at the steam line opens ~ 8%, these problems cause a big loss in condensate pressure that we can't recover the condensate to the header.
Since problems mentioned above, we want to use Steam condensate (145-147C) as the heating fluid for the first bundle (the heat exchanger has 2 bundle), the steam condensate flow rate is about 21000 kg/h with carbon steel pipe size 6".
The problem now is the condensate velocity (tubeside) ~ 0.1 m/s, any serious problem for this velocity (Any fouling occurs? The condensate temp inlet 145-146, oulet ~ 96C).
I need your help to resolve this issue.
Please find attached doc for more esstential information.
I would appreciate your help.
Thank you so much.
Edited by zavtranguyen, 22 April 2020 - 02:23 AM.