A THEORETICAL EQUATION PRESENTING SLOPE IN VAN KREVELEN DIAGRAM FOR BIOMASS PYROLYSIS

Abstract

The van Krevelen diagram has been used widely to describe the change of biomass composition during the thermochemical decomposition. However, the theoretical background on how the composition point of raw material moves towards the point of the product with thermochemical decomposition on the diagram has not been well clarified. This paper attempted to formulate a theoretical equation presenting the slope in van Krevelen diagram based on the removal rates of volatile products during thermochemical decomposition. An equation was established to predict the slope of the movement (or called as the reaction trend line) based on the generated amount of volatiles (H2O, CO2, CO and organics) during thermochemical conversion. This equation was applied to predict some empirical trend lines for torrefaction to confirm the relevamce of this equation, the consistency was excellent. Furthermore, the equation shows its capability in representing other thermal degradation process with a slope variation depending on the raw material.

Keywords

• biomass
• thermochemical decomposition
• van krevelen diagram
• change of composition