I have calculate the HHV of bio-oil derived from pyrolysis process but i want to estimate LHV from HHV for further calculations related to Chemical Exrgy, i want to know is there any correlations for LHV calculation from HHV?
Here is the correlation between LHV and HHV of any hydrocarbon:
LHV = HHV - 0.212*H - 0.0245*M - 0.008*Y
The units of HHV and LHV would be either MJ/kg or GJ/ton
Where:
- H = Percent hydrogen
- M = Percent moisture
- Y = Percent oxygen
As you can see, you will need to perform an ultimate analysis of your bio-oil to determine the amount of carbon, hydrogen, oxygen, nitrogen and sulfur.
Finally, here is the source of this correlation: 2006 IPCC Guidelines, Vol. II, Section 1.4.1.2 .
Hope this helps answer your question and good luck!
Yehia F. Khalil
Dear Professor Yehia F. Khalil
Thank you so much for your valuable guidance, in my experimental work in order to have an accurate determination about the amount of produced bio-oil in the pyrolysis process, i had used DCM to separate bio-oil from possible humidity in the liquid products of pyrolysis (Bio-oil+possible humidity) , and then i had evaporate DCM via vacuum evaporation. after all i want to know should i disregard M (Percent of moisture) in the formula you mentioned?
No. You need to account for the moisture content as shown in the formula. This term accounts for the fact that some of the thermal energy is used for evaporating the moisture and that is why LHV is less than the HHV.
All Best.
Yehia F. Khalil
Thank you so much. Your guidance was very helpful.
“Wish you all the best.”
Dear Babak,
You should consider the bounded water content of you pyrolytic oil, as well. There are numerous routes to separate the water and calculate the LHV regardless of moisture content. The attached paper is one of many. However, to pave the way, you can find the moisture content of your oil either by TGA analysis or different provided standards methods.
Hope this helps,
KK.
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