Open AccessPyrolysis Mechanism of Wheat Straw Based on ReaxFF Molecular Dynamics Simulations
Author(s) -
Zhiwei Liu,
Xiaoke Ku,
Hanhui Jin
Publication year - 2022
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.2c01899
Subject(s) - reaxff , pyrolysis , pyrolytic carbon , straw , hemicellulose , cellulose , lignin , chemistry , chemical engineering , biomass (ecology) , molecular dynamics , tar (computing) , activation energy , molecule , materials science , organic chemistry , computational chemistry , agronomy , hydrogen bond , inorganic chemistry , computer science , engineering , biology , programming language
Biomass has played an increasingly important role in the consumption of energy worldwide because of its renewability and carbon-neutral property. In this work, the pyrolysis mechanism of wheat straw is explored using reactive force field molecular dynamics simulations. A large-scale wheat straw model composed of cellulose, hemicellulose, and lignin is built. After model validation, the temporal evolutions of the main pyrolysis products under different temperatures are analyzed. As the temperature rises, the gas production increases and the tar yield can decrease after peaking. Relatively high temperatures accelerate the generation rates of the main gas and tar species. CO and CO 2 molecules mainly come from the cleavage of CHO 2 radicals, and numerous H 2 O molecules are generated on account of dehydration. Moreover, the evolution of six functional groups and pyran and phenyl rings as well as three types of bonds is also presented. It is observed that the phenyl rings reflect improved thermostability. Finally, the pyrolytic kinetics analysis is conducted, and the estimated activation energy of wheat straw pyrolysis is found to be 56.19 kJ/mol. All these observations can help deeply understand the pyrolytic mechanism of wheat straw biomass.