Upgrading of Bio-oil by Catalytic Esterification and Determination of Acid Number for Evaluating Esterification Degree

Abstract

Bio-oil was upgraded by catalytic esterification over the selected catalysts of 732- and NKC-9-type ion-exchange resins. The determination of the acid number by potentiometric titration was recommended by the authors to quantify the total content of organic acids in bio-oil and also to evaluate the esterification degree of bio-oil in the process of upgrading. We analyzed the measurement precision and calibrated the method of potentiometric titration. It was proven that this method is accurate for measuring the content of organic acids in bio-oil. After bio-oil was upgraded over 732 and NKC-9, acid numbers of bio-oil were lowered by 88.54 and 85.95%, respectively, which represents the conversion of organic acids to neutral esters, the heating values increased by 32.26 and 31.64%, and the moisture contents decreased by 27.74 and 30.87%, respectively. The accelerated aging test and aluminum strip corrosion test showed improvement of stability and corrosion property of bio-oil after upgrading, respectively.

A review of recent laboratory research and commercial developments in fast pyrolysis and upgrading

“…Other recent advances include the development of a new mesoporous catalyst functionalised with propysulfonic acids for esterification, effective for acetic acid conversion [168]. Wang et al [169,170] investigated esterification of bio-oil with 732-and NKC-9-type ion-exchange resins. They proposed Acid Number Determination as a means of assessing the potential of oils to be upgraded and the effectiveness of the upgrading process.…”

Separation of Phenol from Bio-oil Produced from Pyrolysis of Agricultural Wastes

“…These drawbacks make it difficult to be directly used as a vehicle fuel. Therefore, several upgrading technologies have been developed to improve the quality of bio-oil, including catalytic hydrodeoxygenation [7][8][9], catalytic cracking, steam reforming, catalytic esterification, supercritical upgrading and so on [10]. Compared with phenols derived from petroleum fuel, these phenolic compounds are renewable and easily obtained.…”

Selective Production of Aromatic Aldehydes from Heavy Fraction of Bio-oil via Catalytic Oxidation

“…Meanwhile, quinine methide anion (2) converted to quinine methide oxide anion (3). The quinine methide oxide anion (3) can be rapidly converted to phenyl epoxyethane anion (4), which can be attacked by HOO − , resulting in the formation of phenolate anion (5). The phenolate anion (5) degrades by the synchronous cleavage of C-C and O-O bonds to form aromatic aldehyde ions (6).…”

“…1 Upgrading is desirable to remove the oxygen in biooil and this way makes the upgraded bio-oil resemble crude oil. Recently, a lot of work has been reported on bio-oil upgrading, including hydrogenation, 2 catalytic pyrolysis, 3 emulsion, 4 catalytic esterification, 5 and molecular distillation.…”