PREDICTION OF HIGHER HEATING VALUE OF BIOMASS BASED ON ULTIMATE AND PROXIMATE ANALYSES

Abstract

High heating value (HHV) of biomass is important for the design and operation of biomass based energy conversion processes. Experimental determination of this property is always time consuming and expensive. This paper compares existing empirical correlations based on proximate and ultimate analysis of biomass for the determination of the HHV. The correlations were validated from experimental data for twelve biomass that are typical to Nigeria. The correlation based on proximate analysis with the least error is HHV=(354FC+170.8VM)/1000 having a mean absolute error of prediction in the range 0.12 to 5.71 and average absolute error of 0.07 to 24%. The Average absolute error of the correlation HHV=0.3897C+0.2976 from ultimate analysis ranges from 0.09 to 28.9% and the Mean absolute error ranges from 0.015 to 4.71. The predictions from the correlations are not showing good agreement with the experimental data. Ultimately, three correlations were developed in this study. The correlation based on ultimate analysis gave mean absolute prediction error of 0.11 to 2.45 and average absolute error of 0.6 to 16%. The correlation based on a combination of ultimate and proximate analysis gave mean absolute prediction error of 0.08 to 2.05 and average absolute error of 1-12%. The developed correlations are seen to be more accurate in predicting the HHV values. Keywords: Biomass, High Heating Value, Proximate analysis, Ultimate Analysis,