Solid Fuel Molecular Weight & Empirical Formula determination

[mwalshe]

Does anyone know how to determine the Molecular Weight & Empirical Formula of a solid fuel from its ultimate analysis i.e. for a typical solid waste that is intended to be gasified - how would you work out the chemical formula of the fuel & its molecular weight?

 

[FOURe]

Hi there:

In my opinion, one should set up a basic spreadsheet type calculation to find out what the molecular weight of the solid fuel under consideration is.

For a known fuel ultimate analysis breakdown -- it would consist of carbon, hydrogen, sulfur, oxygen, nitrogen and water vapor (ash could be ignored to simplify the calculations) and by knowing the molecular weight value of the listed fuel elements -- it is possible to find out the amount of kmol/kg of each fuel element is by dividing the fuel element fuel mass fraction, kg/kg, by its molecular weight given in kg/kmol.

Once a summation of fuel elements kmol/kg is done, an inverse of it will provide the requested fuel molecular weight.

For the combustion calculation purposes, the fuel ultimate analysis and oxidant composition as well as combustion stoichiometry and combustion reactants inlet temperature values are all what is needed to do basic combustion calculations.

Thanks,

Gordan

http://www.engineering-4e.com

 

[mwalshe]

Thanks for this.

Does anyone know how to calculate the molecular weight of the volatile gas mixture from the pyrolysis of a solid waste? This figure is very important in the calculations of waste & biomass pyrolysis. i.e. when a solid fuel is pyrolysed & partially gasified it will produce a volatile gas mixture - how does one calculate the molecular mass of this volatile fraction?

THANKS