this is the reference that gives the theoretical estimation of HHV 

http://www.sciencedirect.com/science/article/pii/S0016236101001314

Assume 1kg of biomass can be converted to 2m3

of syn-gas (“Modeling Gasifier Mass,” 2010).

2. Standard HHV (Waldheim & Nilsson, 2001) for: H2 = 12.76MJ/m3

; CO = 12.63MJ/m3

; CH4 = 39.76MJ/m3.

3. Syn-gas composition: H2, O2, N2, CH4, CO, CO2. The total percentage of all these gases is 100%.

4. HHV of biomass fuels.

Since only H2, CO and CH4 are combustible, the HHV of syn-gas is the calorific value of these three gases:

ΔH (2m3syn-gas) = (12.76MJ/m3× 2m3× H2%) + (12.63MJ/m3× 2m3× CO%) + (39.76MJ/m3×2m3×CH4%) = 2(12.76 × H2% + 12.63 × CO% + 39.76 × CH4%)MJ/m

reference:http://castle.eiu.edu/~energy/hhv_of_syn_gas.pdf

Dear Mr. Oluwatosin Oginni and Mr. Shahid Munir,

Thank you very much for your answer. It is so helpful. I really do appreciate it. I have just had a meeting with my supervisor yesterday and that went well. From now on, I have no worries with my project research problems because there are experts here to have discussion with. It is an honor to have my questions answered.

Regards,

Swandahru Suryo Kumoro

i have no syngas flow meter and analyser but i have run the 1kw electricity generator, how much it have calorific value. please help and guide any formula.

Hi, you can calculate the HHV/LHV of syngas should you know either its volumetric flowrate or mass flowrate. Multiply the vol/mass % with the heat content values of each constituent gas which are listed in `IEA report of heating value of gases from gasification ` . Link is herein below:

http://www.ieatask33.org/app/webroot/files/file/publications/HeatingValue.pdf