Upgrading fast pyrolysis bio-oil quality by esterification and azeotrop water removal

T. Sundqvist, A. Oasmaa, A. Koskinen

Research output: Contribution to journalArticleScientificpeer-review

27 Citations (Scopus)

Abstract

Fast pyrolysis bio-oil has unfavorable properties that restrict its use in many applications. Among the main issues are high acidity, instability, and water and oxygen content, which give rise to corrosiveness, polymerization during storage, and a low heating value. Esterification and azeotropic water removal can improve all of these properties. In this work, low acidity bio-oils were produced from fast pyrolysis bio-oil via esterification with methanol or n-butanol. Esterification conversion was enhanced by azeotropic water removal prior to and/or during esterification. An additional hydrocarbon entrainer (n-heptane or petroleum ether) was required for efficient water removal. The product oils had total acid numbers ranging from 5 to 10 mg KOH/g and pH values from 4.0 to 5.6. The best results were obtained with 1:0.9:0.1 wt ratio of bio-oil, n-butanol, and n-heptane and p-toluenesulfonic acid (p-TSA) as catalyst. Removal of homogeneous catalyst (2 wt % p-toluenesulfonic acid (p-TSA)) was attempted by precipitation, centrifugation, and water washing, but only 41-82 wt % of the catalyst could be recovered from the product oil based on sulfur content. Solid acid catalysts were more efficient with methanol than n-butanol in dry conditions. An organic base (triethylamine) was tested for neutralizing the methanol esterified bio-oil's residual acidity. Nitrogen content increased by 0.1-0.4 wt % when pH values of 6-8 were obtained.
Original languageEnglish
Pages (from-to)2527-2534
JournalEnergy & Fuels
Volume29
Issue number4
DOIs
Publication statusPublished - 2015
MoE publication typeA1 Journal article-refereed

Fingerprint

Esterification
Oils
Pyrolysis
Water
1-Butanol
Butenes
Acidity
Methanol
Catalysts
Acids
Heptane
Centrifugation
Hydrocarbons
Sulfur
Washing
Ethers
Nitrogen
Crude oil
Polymerization
Oxygen

Cite this

Sundqvist, T. ; Oasmaa, A. ; Koskinen, A. / Upgrading fast pyrolysis bio-oil quality by esterification and azeotrop water removal. In: Energy & Fuels. 2015 ; Vol. 29, No. 4. pp. 2527-2534.
@article{47adf84e4a2943bbb5fd63c7f60dbe00,
title = "Upgrading fast pyrolysis bio-oil quality by esterification and azeotrop water removal",
abstract = "Fast pyrolysis bio-oil has unfavorable properties that restrict its use in many applications. Among the main issues are high acidity, instability, and water and oxygen content, which give rise to corrosiveness, polymerization during storage, and a low heating value. Esterification and azeotropic water removal can improve all of these properties. In this work, low acidity bio-oils were produced from fast pyrolysis bio-oil via esterification with methanol or n-butanol. Esterification conversion was enhanced by azeotropic water removal prior to and/or during esterification. An additional hydrocarbon entrainer (n-heptane or petroleum ether) was required for efficient water removal. The product oils had total acid numbers ranging from 5 to 10 mg KOH/g and pH values from 4.0 to 5.6. The best results were obtained with 1:0.9:0.1 wt ratio of bio-oil, n-butanol, and n-heptane and p-toluenesulfonic acid (p-TSA) as catalyst. Removal of homogeneous catalyst (2 wt {\%} p-toluenesulfonic acid (p-TSA)) was attempted by precipitation, centrifugation, and water washing, but only 41-82 wt {\%} of the catalyst could be recovered from the product oil based on sulfur content. Solid acid catalysts were more efficient with methanol than n-butanol in dry conditions. An organic base (triethylamine) was tested for neutralizing the methanol esterified bio-oil's residual acidity. Nitrogen content increased by 0.1-0.4 wt {\%} when pH values of 6-8 were obtained.",
author = "T. Sundqvist and A. Oasmaa and A. Koskinen",
year = "2015",
doi = "10.1021/acs.energyfuels.5b00238",
language = "English",
volume = "29",
pages = "2527--2534",
journal = "Energy & Fuels",
issn = "0887-0624",
publisher = "American Chemical Society ACS",
number = "4",

}

Upgrading fast pyrolysis bio-oil quality by esterification and azeotrop water removal. / Sundqvist, T.; Oasmaa, A.; Koskinen, A.

In: Energy & Fuels, Vol. 29, No. 4, 2015, p. 2527-2534.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Upgrading fast pyrolysis bio-oil quality by esterification and azeotrop water removal

AU - Sundqvist, T.

AU - Oasmaa, A.

AU - Koskinen, A.

PY - 2015

Y1 - 2015

N2 - Fast pyrolysis bio-oil has unfavorable properties that restrict its use in many applications. Among the main issues are high acidity, instability, and water and oxygen content, which give rise to corrosiveness, polymerization during storage, and a low heating value. Esterification and azeotropic water removal can improve all of these properties. In this work, low acidity bio-oils were produced from fast pyrolysis bio-oil via esterification with methanol or n-butanol. Esterification conversion was enhanced by azeotropic water removal prior to and/or during esterification. An additional hydrocarbon entrainer (n-heptane or petroleum ether) was required for efficient water removal. The product oils had total acid numbers ranging from 5 to 10 mg KOH/g and pH values from 4.0 to 5.6. The best results were obtained with 1:0.9:0.1 wt ratio of bio-oil, n-butanol, and n-heptane and p-toluenesulfonic acid (p-TSA) as catalyst. Removal of homogeneous catalyst (2 wt % p-toluenesulfonic acid (p-TSA)) was attempted by precipitation, centrifugation, and water washing, but only 41-82 wt % of the catalyst could be recovered from the product oil based on sulfur content. Solid acid catalysts were more efficient with methanol than n-butanol in dry conditions. An organic base (triethylamine) was tested for neutralizing the methanol esterified bio-oil's residual acidity. Nitrogen content increased by 0.1-0.4 wt % when pH values of 6-8 were obtained.

AB - Fast pyrolysis bio-oil has unfavorable properties that restrict its use in many applications. Among the main issues are high acidity, instability, and water and oxygen content, which give rise to corrosiveness, polymerization during storage, and a low heating value. Esterification and azeotropic water removal can improve all of these properties. In this work, low acidity bio-oils were produced from fast pyrolysis bio-oil via esterification with methanol or n-butanol. Esterification conversion was enhanced by azeotropic water removal prior to and/or during esterification. An additional hydrocarbon entrainer (n-heptane or petroleum ether) was required for efficient water removal. The product oils had total acid numbers ranging from 5 to 10 mg KOH/g and pH values from 4.0 to 5.6. The best results were obtained with 1:0.9:0.1 wt ratio of bio-oil, n-butanol, and n-heptane and p-toluenesulfonic acid (p-TSA) as catalyst. Removal of homogeneous catalyst (2 wt % p-toluenesulfonic acid (p-TSA)) was attempted by precipitation, centrifugation, and water washing, but only 41-82 wt % of the catalyst could be recovered from the product oil based on sulfur content. Solid acid catalysts were more efficient with methanol than n-butanol in dry conditions. An organic base (triethylamine) was tested for neutralizing the methanol esterified bio-oil's residual acidity. Nitrogen content increased by 0.1-0.4 wt % when pH values of 6-8 were obtained.

U2 - 10.1021/acs.energyfuels.5b00238

DO - 10.1021/acs.energyfuels.5b00238

M3 - Article

VL - 29

SP - 2527

EP - 2534

JO - Energy & Fuels

JF - Energy & Fuels

SN - 0887-0624

IS - 4

ER -