A comparative structural characterisation of different lignin biomass

This study focuses on the structural characterisation techniques of lignin, which is the most abundant component in biomass and commonly produced as residual product in pulp mills industry. It is inexpensive, non-toxic and biodegradable. Four different lignins have been selected for this study including Alcell lignin, Kraft lignin and two milled wood lignins (MWL) derived from coniferous trees (softwoods) and deciduous trees (hardwood). Fourier transform infrared (FTIR) spectroscopy analysis has been performed on all four types of lignin to identify the functional groups present in the lignin structure. The results have indicated that Alcell lignin consists of more desirable functional groups than Kraft lignin with higher phenolic, carbonyl and aromatic groups. Elemental analysis has been performed to examine the carbon and hydrogen content. The elemental analysis results indicates that MWL contain more hydrogen and carbon in comparison to other two commercial lignins. Heating values have been investigated in terms of higher heating value (HHV) and lower heating value (LHV). The lowest values of HHV and LHV have been reported for Kraft lignin due to its condensed structure. The differential thermogravimetry (DTG) analysis have been performed, which determines the maximum degradation temperature of the lignins. The start and maximum degradation temperature for each lignin help to set the pyrolysis temperature of the lignin for bio-oil production. Components that have been observed via Py-GC-MS analysis have indicated that degradation of bonds has led to the formation of three main structural units of lignin known as guaiacyl (G), syringyl (S) and p-hydroxyphenyl propane (p-H)–type. The results indicate that the Py-GC-MS analysis of MWL have higher aromatic components in comparison to the commercially available lignins

Analytical pyrolysis study of different lignin biomass

Lignin represents about 20–30 wt% of the wood content and it is an aromatic polymer composed of phenyl propane units that are connected through ether and condensed (C-C) linkages. It is the major by-product of second-generation bioethanol production. Lignin is a main impurity in the separation of cellulose from wood for pulp and paper. Four different lignins have been selected for this study including Alcell lignin, Kraft lignin and two milled wood lignins (MWL) derived from coniferous trees (softwoods) and deciduous trees (hardwood). Pyrolysis gas chromatography (Py-GC-MS) tests were performed on each sample using CDS 5200 pyrolyser connected to a gas chromatograph with mass spectra Shimadzu GCMS. The pyrolysis products with a phenolic nature obtained by pyrolysis of all four types of lignin has reflected the nature of different lignin origins. The results have shown that more components identified by pyrolysis of MWL (hardwood and softwood) in comparison with commercial lignins (Alcell and Kraft). Components that have been observed via Py-GC-MS analysis indicating that degradation of all four bonds and lead to formation of three main structural units of lignin. The structural analysis of the commercial lignins revealed the partial similarity to the commercially available lignin that means raw materials contains the sufficient aromatics to be used for bio-oil production

A comparative production and characterisation of fast pyrolysis bio-oil from Populus and Spruce woods

This study focuses on the production and characterisation of fast pyrolysis bio-oil from hardwood (Populus) and softwood (Spruce) using a bench-scale pyrolysis reactor at two different temperatures. In this study, a mixed solvent extraction method with different polarities was developed to extract different components of bio-crude oil into three fractions. The obtained fractions were characterized by using gas chromatography and mass spectrometry (GC-MS). The effect of temperature on the production of bio-oil and on the chemical distribution in bio-oil was examined. The maximum bio-oil yield (71.20%) was obtained at 873 K for bio-oil produced from softwood (Spruce). In contrast, at a temperature of 773 K, the bio-oil yields were 62.50% and 65.40% for bio-oil obtained from hardwood (Populus) and softwood (Spruce) respectively. More phenolic compounds were extracted at a temperature of 773 K for bio-oil derived from softwood (Spruce) whereas the bio-oil obtained from hardwood (Populus) produced mostly furans, acids and sugar compounds at this temperature. For both types of bio-oil, a wide variety of chemical groups were identified at a temperature of 873 K in comparison to 773 K

Analytical pyrolysis study of different lignin biomass

Lignin represents about 20–30 wt% of the wood content and it is an aromatic polymer composed of phenyl propane units that are connected through ether and condensed (C-C) linkages. It is the major by-product of second-generation bioethanol production. Lignin is a main impurity in the separation of cellulose from wood for pulp and paper. Four different lignins have been selected for this study including Alcell lignin, Kraft lignin and two milled wood lignins (MWL) derived from coniferous trees (softwoods) and deciduous trees (hardwood). Pyrolysis gas chromatography (Py-GC-MS) tests were performed on each sample using CDS 5200 pyrolyser connected to a gas chromatograph with mass spectra Shimadzu GCMS. The pyrolysis products with a phenolic nature obtained by pyrolysis of all four types of lignin has reflected the nature of different lignin origins. The results have shown that more components identified by pyrolysis of MWL (hardwood and softwood) in comparison with commercial lignins (Alcell and Kraft). Components that have been observed via Py-GC-MS analysis indicating that degradation of all four bonds and lead to formation of three main structural units of lignin. The structural analysis of the commercial lignins revealed the partial similarity to the commercially available lignin that means raw materials contains the sufficient aromatics to be used for bio-oil production

Waste cooking oil valorisation into biodiesel using supercritical methanolysis: critical assessment on the effect of water content

In this work, valorisation of high acid value waste cooking oil (WCO) into biodiesel has been assessed using supercritical methanolysis. The effect of the water content in the feedstock has been critically investigated. Using supercritical methanolysis, the higher water content in the feedstock enhanced the hydrolysis of triglycerides to free fatty acids (FFAs) and the esterification of FFAs into fatty acid methyl esters (FAMEs) has been reported. The effect of water content has been investigated by adding different volumes of water to the feedstock prior to the reaction. Response Surface Methodology (RSM) using Central Composite Design (CCD) has been used to design the experiments and to optimise the experimental variables. Five controllable reaction parameters have been studied including methanol to oil (M:O) molar ratio, reaction temperature, reaction pressure, reaction time and water content. Biodiesel yield has been chosen as reaction response for the experimental runs. The linear effect of reaction parameters and their interactions on biodiesel yield has been analysed. It has been observed that increasing the water content of the feedstock decreases the yield of biodiesel at specific conditions. However, due to the high interactive effect between water content and reaction time, it has been observed increasing effect at longer reaction time. A quadratic model has been developed using the reported experimental results representing biodiesel yield function in all of the experimental parameters. The adequacy of the predicted model has been checked statistically using analysis of variance (ANOVA). Numerical optimisation has been applied to identify the optimal reaction conditions for maximum production of biodiesel. The developed optimal condition has reported 99.8% biodiesel yield at 10:1 M:O molar ratio, 245 oC, 125 bar, 6 vol% of water content within 19 min

A comparative production and characterisation of fast pyrolysis bio-oil from Populus and Spruce woods

This study focuses on the production and characterisation of fast pyrolysis bio-oil from hardwood (Populus) and softwood (Spruce) using a bench-scale pyrolysis reactor at two different temperatures. In this study, a mixed solvent extraction method with different polarities was developed to extract different components of bio-crude oil into three fractions. The obtained fractions were characterized by using gas chromatography and mass spectrometry (GC-MS). The effect of temperature on the production of bio-oil and on the chemical distribution in bio-oil was examined. The maximum bio-oil yield (71.20%) was obtained at 873 K for bio-oil produced from softwood (Spruce). In contrast, at a temperature of 773 K, the bio-oil yields were 62.50% and 65.40% for bio-oil obtained from hardwood (Populus) and softwood (Spruce) respectively. More phenolic compounds were extracted at a temperature of 773 K for bio-oil derived from softwood (Spruce) whereas the bio-oil obtained from hardwood (Populus) produced mostly furans, acids and sugar compounds at this temperature. For both types of bio-oil, a wide variety of chemical groups were identified at a temperature of 873 K in comparison to 773 K

A comparative structural characterisation of different lignin biomass

This study focuses on the structural characterisation techniques of lignin, which is the most abundant component in biomass and commonly produced as residual product in pulp mills industry. It is inexpensive, non-toxic and biodegradable. Four different lignins have been selected for this study including Alcell lignin, Kraft lignin and two milled wood lignins (MWL) derived from coniferous trees (softwoods) and deciduous trees (hardwood). Fourier transform infrared (FTIR) spectroscopy analysis has been performed on all four types of lignin to identify the functional groups present in the lignin structure. The results have indicated that Alcell lignin consists of more desirable functional groups than Kraft lignin with higher phenolic, carbonyl and aromatic groups. Elemental analysis has been performed to examine the carbon and hydrogen content. The elemental analysis results indicates that MWL contain more hydrogen and carbon in comparison to other two commercial lignins. Heating values have been investigated in terms of higher heating value (HHV) and lower heating value (LHV). The lowest values of HHV and LHV have been reported for Kraft lignin due to its condensed structure. The differential thermogravimetry (DTG) analysis have been performed, which determines the maximum degradation temperature of the lignins. The start and maximum degradation temperature for each lignin help to set the pyrolysis temperature of the lignin for bio-oil production. Components that have been observed via Py-GC-MS analysis have indicated that degradation of bonds has led to the formation of three main structural units of lignin known as guaiacyl (G), syringyl (S) and p-hydroxyphenyl propane (p-H)–type. The results indicate that the Py-GC-MS analysis of MWL have higher aromatic components in comparison to the commercially available lignins

Waste cooking oil valorisation into biodiesel using supercritical methanolysis:critical assessment on the effect of water content

In this work, valorisation of high acid value waste cooking oil (WCO) into biodiesel has been assessed using supercritical methanolysis. The effect of the water content in the feedstock has been critically investigated. Using supercritical methanolysis, the higher water content in the feedstock enhanced the hydrolysis of triglycerides to free fatty acids (FFAs) and the esterification of FFAs into fatty acid methyl esters (FAMEs) has been reported. The effect of water content has been investigated by adding different volumes of water to the feedstock prior to the reaction. Response Surface Methodology (RSM) using Central Composite Design (CCD) has been used to design the experiments and to optimise the experimental variables. Five controllable reaction parameters have been studied including methanol to oil (M:O) molar ratio, reaction temperature, reaction pressure, reaction time and water content. Biodiesel yield has been chosen as reaction response for the experimental runs. The linear effect of reaction parameters and their interactions on biodiesel yield has been analysed. It has been observed that increasing the water content of the feedstock decreases the yield of biodiesel at specific conditions. However, due to the high interactive effect between water content and reaction time, it has been observed increasing effect at longer reaction time. A quadratic model has been developed using the reported experimental results representing biodiesel yield function in all of the experimental parameters. The adequacy of the predicted model has been checked statistically using analysis of variance (ANOVA). Numerical optimisation has been applied to identify the optimal reaction conditions for maximum production of biodiesel. The developed optimal condition has reported 99.8% biodiesel yield at 10:1 M:O molar ratio, 245 oC, 125 bar, 6 vol% of water content within 19 min