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Combustion air

Combustion air

Combustion air

(OP)
I need to calculate the air flow (lb/hr) required for burning No#2 oil (Higher calorific value= 20,516 Btu/lb). Here 16.8 lb(allowing 25% excess air) of air is required for burning 1 lb oil. Any help is appreciated.

Thank you.

RE: Combustion air

What more do you need?  I asusme you know the oil burn rate, you have stated the HHV of the oil, and you know the amount of air per pound of fuel.  Fuel is somewhere around 7.5 lbs/cu ft as I recall, I can't think what else you need?

RE: Combustion air


Do you mean that you wish to review the air figure used "here"?

RE: Combustion air

(OP)
Thanks so much for all your responses. The air is heated beforehand in a preheater by steam (maximum flow 250,000 lb/hr) and then fed to the burner. Actually I need the max air flow to this heater which I am trying to figure out from the combustion data.

Is it logical to consider the heated air to give up all the heat to burn the fuel?

heat lost by steam = heat gained by air = heat lost by air= heat gained by fuel
ms(hi-ho)= mf*HCV and ma=16.8*mf
where, m is the lb/hr for steam,fuel & air.

Regards

RE: Combustion air


In theory the sensible heat of the air is added to that of the fuel to produce a certain flame temperature.

However, the pressure drop and the expansion of preheated air, vs cold air, could lead to upsets in burning speed and rate, subjects that should be discussed with the burner manufacturer.

 

RE: Combustion air

shom:

Here are a few plots for ideal and complete stoichiometric combustion of coal, oil and gas with standard air:















I do hope that the above plots will be useful to you.

Thanks,

Gordan
http://members.aol.com/engware

RE: Combustion air

(OP)
Thanks a lot Feric for your plots & also for your spreadsheet where I did pug in my numbers and calculated HHV in Btu/lb. However I calculated the fuel flow from my previously mentioned equation and calculated boiler efficiency that gave me a reasonable figure (74%). Thank you 25362 for your opinion.

Does anyone have idea about the range of power boiler efficiency?

Regards

RE: Combustion air

To All:

My last post sounds like broken English.

I have to admit that it is just being too fast on the trigger.

It was supposed to say:

"I am glad to be of some help ... "

In the future, I will try to take more time before releasing my post.

http://engware.i-dentity.com

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