A fuel consists of 85% C, 12.5% Hydrogen, 2.5% residual matter by mass, Working from 1st
principles, find lower calorific values per kg of fuel.
To find the lower calorific value per kilogram (kg) of the given fuel, we need to consider the lower heating values (LHV) or lower calorific values (LCV) of each component of the fuel and then calculate the weighted average based on their respective mass percentages.
1. C component:
The lower calorific value of pure carbon (C) is known to be 32.8 mega joules per kilogram (MJ/kg).
2. Hydrogen (H) component:
The lower calorific value of hydrogen (H) is 141.8 MJ/kg.
3. Residual matter:
Given that the residual matter accounts for 2.5% of the total mass, we assume that it has no calorific value. So, we can exclude it from the calculation.
Now, let's calculate the lower calorific value per kilogram of the fuel:
Step 1: Calculate the weighted lower calorific value of the C component:
Weighted LCV of C = 85% * (32.8 MJ/kg) = 0.85 * 32.8 MJ/kg
Step 2: Calculate the weighted lower calorific value of the H component:
Weighted LCV of H = 12.5% * (141.8 MJ/kg) = 0.125 * 141.8 MJ/kg
Step 3: Calculate the total weighted lower calorific value:
Total weighted LCV = Weighted LCV of C + Weighted LCV of H
Finally, we obtain the lower calorific value per kilogram of the fuel:
Lower Calorific Value per kg of fuel = Total weighted LCV
You just need to substitute the values from step 1, step 2, and then calculate step 3 to obtain the final answer.