Dear sir, you can refer to  ASTM D 3172-89 standard to calculate proximate analysis of biomass. 

Thank you very much. I have calculated proximate value. but i want to calculate mean proximate analysis on dry basis.

Thank you Sir

Greetings,

If you have values of proximate analysis in wet basis, just divide each value by (1-%moisture). Then you can convert each value from wet to dry basis.

However, if  You have not any value, you should realize experimental tests with specific protocols as it is well mentioned in literature to determine, the moisture content, the volatile matter, the fixed cabon, the HHV/LHV and the ash content.

thank you sir

You can refer to the book; Biomass Gasification and Pyrolysis: Practical Design and Theory.