mechagigatron
Chemical
- Jan 14, 2015
- 1
Hello all
Im looking at getting some rough numbers for energy requirements for a calcination kiln
The kiln feed is a hydrated compound, the goal is to produce an anhydrous product
The way i see it there are 3 things to consider:
1) Enthalpy input required to break the bonds of the hydrated structure and free the water, producing steam and the anhydrous solid
2) Heat energy required to heat and then vaporize free water (moisture) in the feed (including both sensible and latent heat)
3) Heat energy to raise the feed solids to the required temperature at which the de-hydration reaction proceeds quickly enough to be viable
My approach is as follows:
1) Hesse equation (using summed heat of formation: products - reactants in the balanced chem. equation) to find the heat of reaction in kJ/mol_basis. Then convert this number into kJ/kg_feed
2) Q=m*C*deltaT+m*L
3) Q=m*C*deltaT... the problem here is that Perry's does not have the heat capacity (C) for my hydrated compound - only the anhydrous form. I imagine the hydrated compound has a much higher heat capacity than the anhydrous form. Ive found some papers that attempt to measure the hydrated compound Cp but their range of applicable temperature isnt where i need it to be
Once i have 1, 2 and 3 i can apply an efficiency and im off to the races. Ive got some rough numbers in now but the energy requirement values are far too high and im not sure where im going wrong... Can anyone advise if my approach is correct? Also any general advice on how i can obtain the needed Cp values?
Help is much appreciated
Im looking at getting some rough numbers for energy requirements for a calcination kiln
The kiln feed is a hydrated compound, the goal is to produce an anhydrous product
The way i see it there are 3 things to consider:
1) Enthalpy input required to break the bonds of the hydrated structure and free the water, producing steam and the anhydrous solid
2) Heat energy required to heat and then vaporize free water (moisture) in the feed (including both sensible and latent heat)
3) Heat energy to raise the feed solids to the required temperature at which the de-hydration reaction proceeds quickly enough to be viable
My approach is as follows:
1) Hesse equation (using summed heat of formation: products - reactants in the balanced chem. equation) to find the heat of reaction in kJ/mol_basis. Then convert this number into kJ/kg_feed
2) Q=m*C*deltaT+m*L
3) Q=m*C*deltaT... the problem here is that Perry's does not have the heat capacity (C) for my hydrated compound - only the anhydrous form. I imagine the hydrated compound has a much higher heat capacity than the anhydrous form. Ive found some papers that attempt to measure the hydrated compound Cp but their range of applicable temperature isnt where i need it to be
Once i have 1, 2 and 3 i can apply an efficiency and im off to the races. Ive got some rough numbers in now but the energy requirement values are far too high and im not sure where im going wrong... Can anyone advise if my approach is correct? Also any general advice on how i can obtain the needed Cp values?
Help is much appreciated
