This work investigates the kinetics of a pyrolysis reactor. Pyrolysis is demarcated as a two-step process that is the primary and the secondary decomposition of hardwood in the presence of nitrogen. The qualitative aspect of the analysis is performed by allowing the heterogeneous characteristics of the initial distribution function of volatile content. The temperature inside the reactor varies from 19 °C to 363.761 °C. The pressure of producer gas changes from 6 Pa to 26.8 Pa during the pyrolysis of hardwood, which affects the conversion of biomass with respect to temperature. The weighted fraction of the Weibull and the Rayleigh models is used for modeling the mass variation of the biomass inside the rector. The dimension of the reactor used for the experimental work has a length of 400 mm and a cross-sectional area of 9498.5 mm2. The pyrolysis test rig is programed for the cubical form of thermal history [T = (at3 + bt2 + ct − d)].