Abstract
Lignocellulosic biomass is a promising feedstock for renewable fuels and chemical intermediates; in particular, lignin attracts attention for its favorable chemical composition. One obstacle to lignin utilization and valorization is the unknown chemical mechanism that gives rise to the complex product distributions observed upon deconstruction. Among possible deconstruction chemistries, fast pyrolysis is promising due to its short residence time, thus enabling high-volume production. However, the chemistry is inherently complex, thereby hampering the creation of detailed kinetic models describing pathways to specific low molecular products. To this end, we created a detailed kinetic model of lignin decomposition via pyrolysis comprised of 4313 reactions and 1615 species based on pathways suggested by pyrolysis of model compounds in the literature. Using a rule-based reaction network generation approach, a pathways-level reaction network is proposed to predict the evolution of macromolecular species and the formation of various low molecular weight products identified from experimental studies. This reaction network is coupled to a structural model of wheat straw lignin via a kinetic Monte Carlo framework to simulate lignin fast pyrolysis. The mass yields of and speciation within four commonly observed fractions, viz., light gases, an aqueous phase containing water and small oxygenates, char, and a highly complex aromatic fraction, are compared to an experimental report of a putatively similar biomass source. Additional capabilities of the model include the time-resolved prediction of volatilization profiles and the evolution of the molecular weight distribution, which may assist in efforts to valorize lignin to a higher degree than that achieved by current approaches.
Original language | English (US) |
---|---|
Pages (from-to) | 1822-1830 |
Number of pages | 9 |
Journal | Energy and Fuels |
Volume | 32 |
Issue number | 2 |
DOIs | |
State | Published - Feb 15 2018 |
Funding
The authors express thanks to Dr. Xiaowei Zhou, Lauren Dellon, Hanyu Gao, and Lindsay Oakley from Northwestern University for useful discussions. The authors are grateful for financial support by the Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) through the Office of Biomass Program, grant no. DEEE0003044, and ExxonMobil Research and Engineering Co. Funding from the Institute for Sustainability and Energy at Northwestern (ISEN) and the National Science Foundation (CBET-1435228) is also gratefully acknowledged.
ASJC Scopus subject areas
- General Chemical Engineering
- Fuel Technology
- Energy Engineering and Power Technology