Thermal decomposition of ethanol-based biodiesel: Mechanism, kinetics, and effect on viscosity and cold flow property

Jiuxu Liu, Yujie Shen, Yue Nan, Lawrence L Tavlarides

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Thermal decomposition of the ethanol-based biodiesel (FAEEs) was evaluated in batch reactors by thermal exposure at 250-425 °C for durations from 3 to 63 min, with and without the presence of ethanol. The results of GC analysis show that FAEEs were relatively stable at 250 and 275 °C, and stability reduced as temperature and heating time increased. Major decomposition reactions consisted of isomerization, polymerization, and pyrolysis reactions to form isomers, dimers/polymers, smaller chain FAEEs, hydrocarbons, and carboxylic acids the latter of which are not generated in the decomposition of methanol-based biodiesel (FAMEs). This suggests that when applying the sub/supercritical ethanol technology to produce FAEEs, the reaction temperatures must be modest to avoid generating acids which increases the acid value of the final product. A three-lump model was used to predict concentrations of compounds in the FAEEs stressed at 250-325 °C. The decomposition degree of the FAEEs biodiesel was simulated by using first order one-step reaction models (reversible and irreversible), and results show that the reversible model performed better than the irreversible model except for data of 425 °C. The data show that FAEEs are less stable and decompose more completely than FAMEs. The presence of ethanol was shown to reduce the decomposition. Dynamic viscosity was measured, and differential scanning calorimetry (DSC) was used to determine the crystallization onset temperatures to represent cold flow properties. The values are significantly influenced by the polymerization and pyrolysis reactions.

Original languageEnglish (US)
Pages (from-to)23-36
Number of pages14
JournalFuel
Volume178
DOIs
StatePublished - Aug 15 2016

Fingerprint

Biofuels
Biodiesel
Pyrolysis
Ethanol
Viscosity
Decomposition
Kinetics
Polymerization
Acids
Batch reactors
Isomerization
Hydrocarbons
Carboxylic Acids
Crystallization
Carboxylic acids
Isomers
Dimers
Temperature
Methanol
Differential scanning calorimetry

Keywords

  • Cold flow property
  • Ethanol-based biodiesel
  • Kinetics
  • Thermal decomposition
  • Viscosity

ASJC Scopus subject areas

  • Fuel Technology
  • Energy Engineering and Power Technology
  • Chemical Engineering(all)
  • Organic Chemistry

Cite this

Thermal decomposition of ethanol-based biodiesel : Mechanism, kinetics, and effect on viscosity and cold flow property. / Liu, Jiuxu; Shen, Yujie; Nan, Yue; Tavlarides, Lawrence L.

In: Fuel, Vol. 178, 15.08.2016, p. 23-36.

Research output: Contribution to journalArticle

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