Modeling of biomass pyrolysis kinetics using sequential multi-step reaction model

FUEL

卷:237

Article

Burra, Kiran Raj Goud¹  Gupta, Ashwani K.¹ 

[1] Univ Maryland, Dept Mech Engn, College Pk, MD 20742 USA

关键词: Lignocellulose;    Pyrolysis;    Sequential multi-step model;    Inverse modeling;    Kinetics modeling;   

DOI  :  10.1016/j.fuel.2018.09.097

来源: Elsevier

【 摘 要 】

Simultaneous thermal analysis (TGA-DSC) of biomass pyrolysis was conducted to understand the kinetics and energy requirements of biomass pyrolysis. DSC results revealed the energy requirement to heat biomass samples to pyrolysis temperature with contributions from both sensible enthalpy changes along with reaction enthalpy change required to break their chemical bonds. The information obtained was used to determine theoretical energy efficiency of biomass pyrolysis, which was found to be in the range of 86-95%, depending on the sample analyzed, with pinewood providing efficiency of similar to 95%. The TGA results were used for inverse modeling of pyrolysis kinetics of various biomass feedstocks that varied in their source of origin. Sequential multi-step pyrolysis model was explored to understand its capability in representing the global pyrolysis reaction of lignocellulosic wastes since they are carbon neutral and can produce clean and sustainable energy to potentially replace the existing fossil fuel resources with minimal change in existing energy consumption infrastructure. Inverse modeling, by fitting with respect to thermogravimetric analysis (TGA), was carried out using global minimization in an elite multi-objective genetic algorithm and with appropriate choice on the number of reaction steps. Biomass/bio-wastes investigated were cardboard, dry-paper waste, pinewood, rice husk and chicken manure. Cellulose was also investigated as a baseline standard sample. The char formation selectivity of the components involved in biomass was obtained from this model and found similar values for most of the biomasses. A set of similar to 48%, 65% and similar to 70% charring tendencies (based on v(i) values) was common among paper, pinewood, cardboard. The alpha-cellulose decomposition also provided the 70% charring reaction suggesting its role in these biomasses. The obtained multi-step kinetic parameters are considered essential to develop simplified reaction mechanism of biomass gasification and pyrolysis for computational fluid dynamics (CFD) models, which can help in the design of energy efficient and feedstock flexible reactors for sustainable energy production from wastes.

【 授权许可】

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