Temperature and heating rate of solid particles undergoing a thermaldecomposition. Which criteria for characterizing fast pyrolysis?

International audienceThe main purpose of the paper is to discuss the advantages and drawbacks of the great number of con-ditions revealed by the literature for characterizing biomass fast pyrolysis. They are often related totemperature and heating rate. Unfortunately, significant inconsistencies exist between the values rec-ommended by the authors. In order to bring new insights to this problem, a very simple model of solidpyrolysis is solved in the case of global primary cellulose pyrolysis. The operating conditions are chosenin order to cover almost all practical situations. The two cases of fixed heat source temperature and oftemperature increasing with time are considered. The results show that actual particle temperature andheating rate are inappropriate for defining fast pyrolysis.Other criteria are also discussed. Among them, reactor temperature and external heat transfer coeffi-cient appear to be more relevant, as well as efficiency of primary products removal. However, it is shownthat the definition of fast pyrolysis reactor optimal conditions cannot rely on only one criterion. Allimplied parameters should be taken into account in