Hello every one,
I need to calculate higher heating value of syngas produced from gasification. following are the methods i have taken from literature/ some thesis.
1- HHV = (30.18×CO + 30.52×H2 + 9.5× CH4) × 4.18
In this method I dont know what is these values referring to (30.18, 30.52, 9.5, and 4.18)?
by adopting this method;
= (30.18 * 21 mol% + 30.52 * 13.42 mol% + 9.5 * 21.51) * 4.18
= 5.21 MJ/m3
2- Standard HHV for H2 = 12.76 MJ m3; CO = 12.63MJ m3; CH4 = 39.76 MJ m3 (Waldheim and Hilsson, 2001).
∆H = 12.76 × H2 mol % + 12.63 × CO mol % + 39.76 × CH4 mol %
= 12.76MJ m3 × 13.42mol% + 12.63MJ m3 × 21mol% + 39.76MJ m3 ×
21.51 mol%
= 13 MJ m3
In this second method (2) i can understand that the values presented in equation are standard as i have mentioned reference too. but the higher heating value is much more than first method (1) using same syngas gas yield components.
Thus i m not sure which method is accurate. specially for first method i dont have any strong reference except a thesis from where i have that equation and dont kwn abt the values present in that education whether these are standard or some thing else.
It would be great if any one can explain regarding theSE values mentioned in first method (30.18, 30.52, 9.5, and 4.18) and any reference.
Dear ,
for better understanding of fundamentals, I suggest you to go through the attached lecture pdf.
Moreover, We need to clarify the used unit of the first method.
The unit itself would be the answer of the question!, I guess it is Mj/kg, you may refer Power Plant Engineering by P. K. Nag page 163, 2ed attachment.
Best Regards!
Azd.
Dear Abdul,
if I use your first equation for calculation, I achieve a result of 52.15. The factor of 4.18 indicates that the calculation has something to do with calories (1 calory = 4.18 J). What is irritating is the fact that the factors for CO and H2 are larger compared to the second equation, while the one for methane is smaller.
More in detail, the ratio between the factors (eq. 2/eq. 1) is 0.418 for CO and H2 and 4.18 for CH4. I think this is no coincidence.
Altogether, I think that equation 2 is correct. Equation 1 calculates with calories and has some errors. A corrected version of equation 1 could be:
HHV = (3.018×CO + 3.052×H2 + 9.5× CH4) × 4.18
With all values in mol/mol, and the result being in MJ/m³.
With this, the equation gives 12.9 MJ/m³, comparable to equation 2.
Best wishes
Andreas
Dear Abdul
if your aim is to calculate the heating value of produced gas, nedd to use the LHV.
you can find it this article "Investigation on syngas production via biomass conversion through the integration of pyrolysis and air–steam gasification processes"
HHV is applied for solid product (Char) heating value that you need to use bomb calori-meter.
You can find this book "Advanced Energy Systems, Second Edition"
https://books.google.co.kr/books?id=BSAtAgAAQBAJ&pg=PA42&lpg=PA42&dq=formula+heating+value+of+natural+gas+mj+m3&source=bl&ots=zecfUMK0Yz&sig=uOi7RcOh3JNxWH5JUBmB1DCFO-I&hl=ko&sa=X&ved=0CG0Q6AEwCWoVChMIwZ-Qi8aCxwIVZhemCh286AAv#v=onepage&q=formula%20heating%20value%20of%20natural%20gas%20mj%20m3&f=false
Dear Abdul Raheem,
You may calculate LHV of syn gas by the given equation;
LHV= (CO x 30.18) + (H2 x 25.76) + ( CH4 x 85.78) = K cal/M3
Regards.
Muhammad Imran
Hi Abdul Raheem,
Do you have the syngas composition or have an idea of what it would be?
I suggest you apply the weighted arthmetic mean method considering the LHV (Lower heating value) or net calorific value of each gas component. I think the methods suggested above by our mates work as well, but if you look for more accurate data, consider the syngas yield.
Cheers,
Humberto
Hi,
Did you have any CO2 in your produced gas? Why did you ignore that?
- Badges
- Science topic