Combined NMR structural characterization and thermogravimetric analyses for the assessment of the AAEM effect during lignocellulosic biomass pyrolysis

Khouloud Haddad, Mejdi Jeguirim*, Salah Jellali, Chamseddine Guizani, Luc Delmotte, Simona Bennici, Lionel Limousy

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)

Abstract

The goal of the present research is to study the effect of the inorganic species on the pyrolysis mechanism of lignocellulosic biomass. Many contradictions as the catalytic role of inorganic salts characterize the research works published up to now. These ambiguities are reasonably due to the morphological and structural modifications of the reacting biomass by the various demineralization and impregnation methods, that impact on the pyrolysis mechanism. In order to clarify the effect of inorganics on the pyrolysis mechanism, alkali and alkaline earth (AAEM) containing salts were deposited by impregnation method on cypress sawdust. Nuclear magnetic resonance analyses showed that the biomass structure was preserved and that metal deposition passes through a cationic exchange mechanism. The thermogravimetric analyses show that AAEMs have different effects by influencing the degradation behavior and the mass balances. In particular, potassium and sodium elements accelerated the hemicellulose thermal degradation without modifying the reaction mechanism. In addition, they showed a catalytic effect in the cellulose degradation towards low weight molecules decomposition and condensation reactions leading to the increase of the char yield. Contrary, the presence of magnesium and calcium seems to inhibit the hemicellulose thermal degradation without a significant effect on the cellulose degradation mechanism.

Original languageEnglish
Pages (from-to)10-23
Number of pages14
JournalEnergy
Volume134
DOIs
Publication statusPublished - 2017
Externally publishedYes

Keywords

  • Alkali and alkaline earth metals
  • Lignocellulosic biomass
  • Pyrolysis
  • Thermogravimetry

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Modelling and Simulation
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Pollution
  • Energy(all)
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Management, Monitoring, Policy and Law
  • Electrical and Electronic Engineering

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