The talk addresses the effects of heat treatment conditions on the products of pyrolysis of coal and lignocellulosic biomass over an extremely wide range of operating conditions. The experimental campaign included indeed experiments in Fixed Bed Reactor, Drop Tube Reactor, Heated Strip Reactor and Flat Flame Burner, at temperatures of 700-2300 K, heating rates of 0.1-105 K/s and residence times of 0.02-20000 s. Purely inert and carbon dioxide rich atmospheres are also scrutinized. In the early stages of heat treatment, transformations at both the structural and chemical level are dramatic and well recognized in the literature under the name of pyrolysis. Further heat treatment, even in parallel with heterogeneous reaction, produces less evident changes, but still is very impactful on the char reactivity in the late stages of burn-off, which are recognized in the literature under the name of Thermal Annealing. Chars are characterized by a multitude of techniques, ranging from simple proximate analysis to TGA and advanced microscopic and spectroscopic analysis (XPS, raman etc). The tendency of biomass and coal to undergo graphitization over a broad range of heat treatment conditions is compared and the concepts developed for Thermal Annealing of coal are modified in order to be applied to lignocellulosic materials, where multiple components with different inertia to thermal treatment are present. Tars are analyzed by Gas Chromatography-Mass Spectrometry, Size Exclusion Chromatography and Ultraviolet-visible spectroscopy. A special experimental technique is also presented which allows to minimize secondary reactions in the gas phase and shed light on the primary products of pyrolysis. Primary tars from coal and biomass are compared. Moreover the role of Cellulose, Hemicellulose and Lignin on the chemical composition of biomass tars is discussed.
Effects of heat treatment conditions on the products of coal and biomass pyrolysis
Osvalda Senneca;Francesca Cerciello;Carmela Russo;
2019
Abstract
The talk addresses the effects of heat treatment conditions on the products of pyrolysis of coal and lignocellulosic biomass over an extremely wide range of operating conditions. The experimental campaign included indeed experiments in Fixed Bed Reactor, Drop Tube Reactor, Heated Strip Reactor and Flat Flame Burner, at temperatures of 700-2300 K, heating rates of 0.1-105 K/s and residence times of 0.02-20000 s. Purely inert and carbon dioxide rich atmospheres are also scrutinized. In the early stages of heat treatment, transformations at both the structural and chemical level are dramatic and well recognized in the literature under the name of pyrolysis. Further heat treatment, even in parallel with heterogeneous reaction, produces less evident changes, but still is very impactful on the char reactivity in the late stages of burn-off, which are recognized in the literature under the name of Thermal Annealing. Chars are characterized by a multitude of techniques, ranging from simple proximate analysis to TGA and advanced microscopic and spectroscopic analysis (XPS, raman etc). The tendency of biomass and coal to undergo graphitization over a broad range of heat treatment conditions is compared and the concepts developed for Thermal Annealing of coal are modified in order to be applied to lignocellulosic materials, where multiple components with different inertia to thermal treatment are present. Tars are analyzed by Gas Chromatography-Mass Spectrometry, Size Exclusion Chromatography and Ultraviolet-visible spectroscopy. A special experimental technique is also presented which allows to minimize secondary reactions in the gas phase and shed light on the primary products of pyrolysis. Primary tars from coal and biomass are compared. Moreover the role of Cellulose, Hemicellulose and Lignin on the chemical composition of biomass tars is discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
