Division of Chemical Engineering and Renewable Energy, School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
Electrochemical Innovation Lab, Department of Chemical Engineering, Faculty of Engineering Sciences, University College London, Gower Street, London, WC1E 7JE, UK.
Sci Rep. 2021 Jan 29;11(1):2656. doi: 10.1038/s41598-020-80228-x.
Accurate modelling of particle shrinkage during biomass pyrolysis is key to the production of biochars with specific morphologies. Such biochars represent sustainable solutions to a variety of adsorption-dependent environmental remediation challenges. Modelling of particle shrinkage during biomass pyrolysis has heretofore been based solely on theory and ex-situ experimental data. Here we present the first in-situ phase-contrast X-ray imaging study of biomass pyrolysis. A novel reactor was developed to enable operando synchrotron radiography of fixed beds of pyrolysing biomass. Almond shell particles experienced more bulk shrinkage and less change in porosity than did walnut shell particles during pyrolysis, despite their similar composition. Alkaline pretreatment was found to reduce this difference in feedstock behaviour. Ex-situ synchrotron X-ray microtomography was performed to study the effects of pyrolysis on pore morphology. Pyrolysis led to a redistribution of pores away from particle surfaces, meaning newly formed surface area may be less accessible to adsorbates.
准确模拟生物质热解过程中的颗粒收缩是制备具有特定形态的生物炭的关键。这种生物炭为各种依赖于吸附的环境修复挑战提供了可持续的解决方案。迄今为止，生物质热解过程中的颗粒收缩模型仅基于理论和原位实验数据。在这里，我们首次进行了生物质热解的原位相衬 X 射线成像研究。开发了一种新型反应器，以实现固定床生物质热解的同步辐射射线照相术。杏仁壳颗粒在热解过程中的体相收缩比核桃壳颗粒多，而孔隙率变化比核桃壳颗粒小，尽管它们的组成相似。发现碱性预处理可以减少这种原料行为的差异。进行了同步加速器 X 射线微断层扫描以研究热解对孔形态的影响。热解导致孔从颗粒表面重新分布，这意味着新形成的表面积可能对吸附剂的吸附性较差。
