Modular Boilers Exhaust design
Modular Boilers Exhaust design
(OP)
Hi Guys,
I am looking assistance in finding exhaust header & stack sizes for 3 modular hot water boilers. Each boiler has 24" exhaust flange. I am planning to breach them in one common header & then connect to stack.
I have existing 2 stacks available each 16" big. How I find the common header size from 3 boilers exhausts & stack size. Can I use two stacks connected with one common header, this way size for required stack will be divided in two.
Appreciated for suggestions & any tech referneces.
Thanks
I am looking assistance in finding exhaust header & stack sizes for 3 modular hot water boilers. Each boiler has 24" exhaust flange. I am planning to breach them in one common header & then connect to stack.
I have existing 2 stacks available each 16" big. How I find the common header size from 3 boilers exhausts & stack size. Can I use two stacks connected with one common header, this way size for required stack will be divided in two.
Appreciated for suggestions & any tech referneces.
Thanks





RE: Modular Boilers Exhaust design
More information is required, what are exhaust gas flows and temperatures, lengths of ducting?
athomas236
RE: Modular Boilers Exhaust design
The 3 boilers will be fitted in a boiler room (in basement) having 28'X19' space, while each module is 5.5'X4.5' in size. The two existing stacks (16" each) is located on opposite corner of room.
Again I will ask in general, can we connect two stacks with one common exhaust header (each on two ends), this will divide the exhaust gas into halves & stack size will be half.
Thanks agian
rahim
RE: Modular Boilers Exhaust design
sorry, ya need to provide the data athomas236 stated or at least provide the boiler duty.
good luck!
-pmover
RE: Modular Boilers Exhaust design
Guys appreciated your help. Its natural draft & 3 modular boilers each of 49 H.P.
Regards
RE: Modular Boilers Exhaust design
Here are some numbers for you to think about:
49HP @ 33472BTU/h for 1HP = 1.64million BTU/h=0.4806MW
With boiler efficiency of 75% and GCV of oil of 41MJ/kg, fuel consumption is 0.4806/(41*0.75)=0.0156kg/s = 124lb/h
With 4% O2 in flue gas (dry volume basis) ratio of flue gas to fuel is 18.06, so flue gas flow is 2240lb/h.
With flue gas temperature of 300C, gas constant of 286.7J/kg K and limiting gas velocity of 15m/s, the required duct diameter is 8 inches.
Of course all these numbers are all rough estimates and are made without any knowledge of your actual plant, but at least you have numbers.
Regards,
athomas236