3 replies to this topic

[tlk]

DO YOU KNOW (CAN YOU HELP) HOW TO CALCULATE THE FLUE GAS FLOW here? 

A steam power plant is fired on forestry residues (chipped branches and tree-tops). The fuel power of the boiler is 100 MW_th, which is the raw energy content of the wood fuel entering the boiler.  
Use the relevant diagrams from the help file and calculate the efficiency of the boiler via the indirect method.  

The following is given: 
Flue gas temperature                                             206   °C 
Ash content (A) in the wood on total basis                 1.5 % 
Moisture content in fuel on total basis (mass %):       20 % 
Radiation losses measured as                                    0.8 %  
The ideal gas law can be used to estimate the normal density of NO₂.

Measured in Flue gases (vol %): 
[O₂]_{dry gas}                                                          3.8% 
[CO]_{dry gas} (Carbon monoxide)                                     ₁₇₀ ppm 
[H₂O]                                                                 14.7 % (wet flue gas) 
[NO₂]_{drygas                                                                                   110} ppm

Measured in the Residual ash: 
Unburned material (≈ elemental carbon) in residual ash (mass %): 9%

Take into account the following energy losses from the boiler: 
1. Flue gas thermal loss (due to high temperature of exhaust gases) 
2. Carbon monoxide in flue gas (partial combustion of the fuel) 
3. Unburned in residual ash (incomplete combustion of solid particles) 
4. Radiation loss (heat loss from boiler walls to surroundings) 

[PingPong]

Not enough data given, so nothing can be calculated.

 

Moreover we do not know the relevant diagrams or what is meant by the indirect method.

[tlk]

ok, I understand. But I wonder if there is a formula for flue gas flow or how to come to the right direction for the right answer?

 

there is more data (Sorry that I missed it)

 

air axcess factor m=1,24

CO2 percentage in flue gas 16.3%

Total gas amount g=5.76 mn3/kg fuel (if i have the right LHV för the fuel -forestry residues)

 

Thanks

[breizh]

http://hydrogen.pnl....?canprint=false

 

tlk ,

 

Consider the link above for heating value of fuels .

 

Regards

 

Breizh