How To Perform An Energy Balance Around A Burner 1

[ChemicalAg]

I would like to perform a energy balance around a natural gas burner used to supply heat to a fluidized bed.

I would appreciate some literature to read and some helpful tips.

 

[dcasto]

in - out + generation = accumulation

These guys are good and they'll teach you everything

http://www.johnzink.com/

 

[chemebabak]

1. If you are supplying heat to a fluidized bed you must first calculate the heat adsorbed by the media. Q = mass of media * (Operating temperature - adsorbent temp at time 0) * media specific heat.
2. Then you need to calculate the heat adsorbed by the steel in the vessel.
3. If you are evaporating an adsorbed fluid from the media you need to consider the heat of vaporization also.
4. Assume a 5% heat loss.
5. consider a factor of heat required to maintain the temperature in the vessel. That is a the heat supplied by a X°F fluid does not all transfer to the adsorbent media.

Of course you also need the flow rate of the fluid to be heated.

Total Q =
1. mass of media * Cp * delta T
+ 2. mass of steel * Cp * delta T
+ 3. delta H evap
+ 4. 0.05* sum(1, 2 and 3)
+ 5. factor * sum(1, 2, 3, and 4) (GPSA recommends factor = 2.5)

Calculate the fluid flow rate. Divide total Q by (Cp * delta T of fluid * total heating and media regeneration time).

The energy balance around the burner is
Q = flow * Cp * delta T of fluid.
The quantity of Natural Gas required is
NG = Q / LHV of NG / burner efficiency.

 

[macmet]

Dcasto,

Have you taken any of these courses? I'm not in the Tulsa area, but the online course seems interesting. Any idea if it's worthwhile?

 

[sshep]

For energy balance around a burner, use the Gibbs reactor model in Aspen-plus to find the adiabatic flame temperature for any fuel gas composition and air mix. This also predicts the NOx if these components have been defined- no stochiometry is needed. Then cool the hot stream as required to fit the energy balance around the process (heat losses, reactions, flue gas, steam generation, etc).

Despite all competition, John Zink is still the best in the business, even here in South Africa. Just yesterday I found out that Koch-Glitsch uses John Zink for all their CFD modeling- i.e. John Zink is alot more than just sales of combustion equipment.

best wishes always,
sshep

 

[dcasto]

I went to John Zink school in 1977, it was great for a kid.