Clemente-Castro S, Palma A, Ruiz-Montoya M, Giráldez I, Díaz M J
Department of Chemical Engineering, Physical Chemistry and Materials Science. ProTecS - Product Technology and Chemical Processes Research Centre. University of Huelva, Campus "El Carmen", Spain.
Department of Chemistry "Prof. José Carlos Vílchez Martín". ProTecS - Product Technology and Chemical Processes Research Centre. University of Huelva, Campus "El Carmen",Spain.
Heliyon. 2023 Jul 6;9(7):e17943. doi: 10.1016/j.heliyon.2023.e17943. eCollection 2023 Jul.
is a fast-growing leguminous biomass with great energetical and value-added chemical compounds potential (saccharides, biogas, bio-oil, etc.). Using the thermogravimetric and derivative thermogravimetric curves, the different trends followed by L. leucocephala during pyrolysis, 0.25 equivalence ratio (ER) of gasification, 0.50 equivalence ratio of gasification and combustion were analyzed, and the activation energies were obtained by Distributed Activation Energy Model (DAEM) method. Gas samples were collected through adsorption tubes during the gasification at 0.25 ER and 0.50 ER to observe the distribution of the main chemical products in this process by gas chromatography/mass spectrometry and were compared with pyrolysis products. It was found that small amounts of oxygen have changes in the kinetics of the process, leading to significant decreases in the activation energy at the beginning of the degradation of components such as cellulose (from 170 to 135 kJ mol at 0.25 conversion at 0.50 ER gasification). The activation energy of lignin disintegration was also reduced (342 kJ mol), assimilating the beginnings of gasification processes such as the Boudouard reaction. 0.50 ER gasification is potentially an interesting process to obtain quality bio-oil, since a large amount of hexane is detected (44.96%), and value-added oxygenated intermediates such as alcohols and glycols. Gasification at 0.25 ER, on the other hand, is much more similar to pyrolysis, obtaining a wide variety of short-chain compounds resulting from the disintegration of the main lignocellulosic components, especially ketones such as 1-hydroxypropan-2-one (19.48%), and notable amount of furans and anhydrosugars like d-allose (5.50%).
是一种快速生长的豆科生物质，具有巨大的能源和增值化合物潜力（糖类、沼气、生物油等）。利用热重曲线和微商热重曲线，分析了银合欢在热解、0.25当量比（ER）气化、0.50当量比气化和燃烧过程中呈现的不同趋势，并通过分布活化能模型（DAEM）方法获得了活化能。在0.25 ER和0.50 ER气化过程中，通过吸附管收集气体样品，利用气相色谱/质谱法观察该过程中主要化学产物的分布，并与热解产物进行比较。研究发现，少量氧气会改变该过程的动力学，导致纤维素等成分降解开始时的活化能显著降低（在0.50 ER气化、0.25转化率时，从170 kJ/mol降至135 kJ/mol）。木质素分解的活化能也有所降低（342 kJ/mol），类似于布多阿尔德反应等气化过程的开始。0.50 ER气化可能是获得优质生物油的一个有趣过程，因为检测到大量己烷（44.96%）以及醇类和二醇类等增值含氧中间体。另一方面，0.25 ER气化与热解更为相似，获得了由主要木质纤维素成分分解产生的多种短链化合物，尤其是1-羟基丙酮（19.48%）等酮类，以及大量呋喃和脱水糖如d-阿洛糖（5.50%）。
