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Woody (Albizia pedicellaris and Terminalia ivorensis) and non-woody (guinea corn (Sorghum bicolor)) glume and stalk biomass resources from Nigeria were subjected to thermo-analytical and physico-chemical analyses to determine their suitability for thermochemical processing. They were found to have comparably high calorific values (between 16.4 and 20.1 MJ kg-1). The woody biomass had very low ash content (0.32%), while the non-woody biomass had relatively high ash content (7.54%). Thermogravimetric analysis (TGA) of the test samples showed significant variation in the decomposition behavior of the individual biomasses. Gas chromatography/mass spectrometry (GC/MS) of fatty acid methyl esters (FAMEs) derivatives indicated the presence of fatty and resin acids in the dichloromethane (CH2Cl2) extracts. Analytical pyrolysis (Py-GC/MS) of the samples revealed that the volatiles liberated consisted mostly of acids, alcohols, ketones, phenols, and sugar derivatives. These biomass types were deemed suitable for biofuel applications. [ABSTRACT FROM AUTHOR]

Abstract: The effect of cellulose crystallinity on the formation of a liquid intermediate and on its thermal degradation was studied thermogravimetrically and by Py-GC/MS using a control cellulose (Avicel, crystallinity at 60.5%) and ball-milled Avicel (low cellulose crystallinity at 6.5%). The crystallinity of the materials studied was quantified by XRD and FTIR. Thermogravimetric analyses (TGA) show the samples with lower crystallinity start to degrade at lower temperatures, exhibiting sharper DTG curves and lower thermal degradation activation energies. Scanning electron microscopy (SEM) studies of the solid residues formed in TGA tests showed that, while the conversion of the ball-milled cellulose (mostly amorphous cellulose) occurs through the formation of a liquid intermediate, in the conversion of the control the fibrous structure is conserved. Py-GC/MS studies showed major differences in the thermal behavior of the samples studied. At 300°C, amorphous cellulose yielded more levoglucosan. At temperatures between 350 and 450°C, higher yields of mono-anhydrosugars (levoglucosan and levoglucosenone) were obtained with the samples with higher crystallinity (control). The ball-milled cellulose produced more 5-(hydroxymethyl) furfural, 5-methylfurfural and furfural. The higher yields of these compounds are due to the acceleration of dehydration reactions when a liquid phase intermediate was formed. Fragmentation reactions responsible for the formation of light compounds (glycoaldehyde, acetic acid, methyl-vinyl-ketone and acetol) and the reactions responsible for the formation of cyclopentane do not seem to be affected by cellulose crystallinity and by the formation of a liquid intermediate. [Copyright &y& Elsevier]

Graphical abstract Highlights • Grown field cultured algae that was fed with diary manure waste water. • Compared field cultured to food grade commercial algae by their chemical and thermal properties. • Bio-oil, biochar and gas products were produced by pyrolysis and yields were temperature dependent. • Pyrolysis bio-oil mainly contained lipid derived compounds. Abstract Chlorella vulgaris algae is comprised of a complex mixture of compounds such as carbohydrates, lipids, and proteins and is a suitable feedstock for biofuels. The aim of this study was to convert commercial and a low cost field cultivated algae, via pyrolysis, to produce bio-oil, synthesis gas, and biochar products. The thermal degradation behaviour of algae was investigated by thermogravimetric analysis. Proximate, ultimate, fatty acid methyl ester and carbohydrates analyses, and pyrolysis–GCMS were further employed to characterize the chemical components of algae. Commercial and field cultured C. vulgaris algae was pyrolyzed (450, 500, and 550 °C) and their pyrolysis products were collected and characterized. The highest biochar yield was 42% at 450 °C and the highest bio-oil yield was 47.7% at 550 °C. The biochar physical and chemical properties were assessed using proximate and ultimate analysis, calorific value, specific surface area, butane absorption activity, Raman spectroscopy, and electron microscopy. Algae biochar was found to be mostly composed of condensed phenolic compounds and majorly disordered amorphous carbon. The bio-oils were characterized by the combination of GC–MS, high-pressure liquid chromatography, and electrospray ionization mass spectrometry. Fatty acids, carbohydrates, nitrogen-containing compounds, and aromatic hydrocarbons were abundantly found in the algae bio-oil. [ABSTRACT FROM AUTHOR]

Brewer’s spent grains, major by-products of the beverage industries, were obtained from a Nigerian brewery and subjected to pyrolysis at 500 °C. Analytical pyrolysis (Py-GC/MS) was conducted on the original BSG, extractive-free BSG and BSG CH 2 Cl 2 extract. There was a marked difference in the concentration of levoglucosan between the extractive-free BSG (40.5%) and the original BSG (11.5%). The Py-GC/MS detected significant amount of palmitic and oleic acids in the three samples. Prior to pyrolysis, the extractives content were isolated through methanolysis, transesterified and subjected to GC/MS analysis. The analysis revealed the presence of linoleic, oleic and palmitic acids in an appreciable quantity. The BSG and its biochar were also characterised according to Fourier transform infrared and Raman spectroscopic, and thermogravimetric analyses alongside some conventional physico-chemical analysis. The total crystallinity and condensation indices were evaluated from specific FTIR spectra peaks so as to monitor structural transformations in the bio-char. Kinetic data were deduced from TGA measurements and it was apparent that thermal decomposition of BSG is better modelled as a multi-step reaction mechanism. The nitrogen content of the bio-char was relatively high making it a suitable feedstock for the production of in situ nitrogenised activated bio-carbon. There was a significant variation between the structural configuration of the original BSG and the bio-char as revealed by the change in the value of the condensation index as well as the cellulose crystallinity content. It may thus be concluded that the BSG biomass would be a viable feedstock for thermal decomposition and other valorisation processes. [ABSTRACT FROM AUTHOR]

Nickel (Ni) and ruthenium (Ru) decorated nanosprings (Ni-NS and Ru-NS) were prepared for use as potential hydrodeoxygenation (HDO) catalysts. The nanocatalysts were characterized by BET surface area measurements, electron microscopy and X-ray diffraction (XRD) and showed the NSs had a helical and mesoporous structure. The Ni and Ru decorated NSs showed good metal dispersity at the NS surface. Catalytic HDO conversion of phenol (model bio-oil compound) using NS were compared to conventional alumina (Al 2 O 3 ) and silica (SiO 2 ) gel catalyst supports. Ni–Al 2 O 3 was easily deactivated in the presence of water while the Ni-NS catalysts performed very well irrespective of water being present. An increase in Ni loading (up to 50%) increased the Ni-NS activity while the high loading resulted in a detrimental effect on the activity of silica gel based catalysts. Ru based catalysts showed better activity and conversion on phenol HDO than Ni based catalysts, even in the presence of water. Ponderosa pine pyrolysis bio-oil was fractionated into water-soluble (WS) and water-insoluble (WI) fractions. The bio-oil WI fraction was first hydrocracked to lower its molar mass and then HDO treated with Ni-NS to successfully form cycloalkanes products. These NS based HDO catalysts show promise for upgrading pyrolysis bio-oils to biofuels. [ABSTRACT FROM AUTHOR]

This study evaluates the potential of a mixed fast and slow pyrolysis process for the conversion of four feedstocks (i.e., hybrid poplar, maple, pine, and sugarcane bagasse) into bio-oil and biochar. The novelty of this study lies within the integration of a free-fall reactor with a batch reactor to take advantage of both fast and slow pyrolysis, and adapt conversion parameters (e.g., carrier gas pressure, feedstock particle size, bulk density, reactor height, and path tortuosity) to maximize the desired product quality and yields. Thermogravimetric analysis was used to provide insight into the thermal degradation of the specified feedstock. Biomass samples were pyrolyzed at 500–550 °C, and the conversion products were evaluated. Biochar properties were characterized using proximate and ultimate analyses and surface area. Bio-oil characterization was obtained by gas chromatography-mass spectrometry (GC-MS), electrospray ionization-mass spectrometry (ESI-MS), Fourier transform infrared (FTIR) spectroscopy, and thermal stability testing. GC-MS identified dominant bio-oil compounds, such as levoglucosan, furfural, and acetic acid. ESI detected molecular weights that are higher than average, necessitating further in-situ cracking (e.g., thermal or catalytic). FTIR showed similar peak patterns and functional groups across the feedstock. The results show that maple produced the greatest biochar yield at 56%, while hybrid poplar had the greatest bio-oil yield at 38%. Among the feedstocks, bio-oil produced from hybrid poplar presents a promising oil with the lowest moisture content (<20%), high phenol content, and the most thermally stable properties, while bio-oil from pine had the next best thermal stability, but with the highest content of levoglucosan (a favorable platform molecule). Analytical results are compared to prior studies to identify the advantages and disadvantages of the free-fall fast pyrolysis reactor. Shortcomings of the current reactor configuration are identified, along with the direction for future studies. • This study evaluates the potential of a mixed fast and slow pyrolysis process. • Four feedstocks of varying characteristics are pyrolyzed and products examined. • Fast Pyrolysis was carried out in a free-fall reactor operating at 500–550 °C. • Quality and yield were dependent on biomass particle size and feedstock type. • Pine and hybrid poplar produced bio-oil with best stability and chemical properties. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoate (PHA) production generates a significant amount of residual bacterial biomass (RBB) after PHA extraction. The RBB as a zero-value waste contains proteins, carbohydrates, phenolics, and ash, which can be managed and converted to bio-oil and biochar products by pyrolysis. Thermogravimetric analysis (TGA) was used to investigate the thermodegradation kinetics of RBB and pyrolysis–GCMS studies were employed to determine potential chemical products. Pyrolysis was conducted on a laboratory-scale auger reactor at 500 °C. The bio-oil and biochar yield were 28 and 46%, respectively. The pyrolysis bio-oil was characterized by the combination of GCMS, high-pressure liquid chromatography (HPLC), and electrospray ionization mass spectrometry (ESI–MS). The bio-oil was dominated by nitrogen-containing, hydrocarbons, and aromatic compounds. The biochar was studied for its specific surface area and pore size, chemical functionality by Fourier transform infrared (FTIR) and Raman spectroscopies, and butane absorption activity. Biochar was comprised of a large part of polycondensed phenolic and majorly disordered amorphous carbon. [ABSTRACT FROM AUTHOR]

Pyrolysis of polypropylene (PP) with an equilibrium fluid catalytic cracking (FCC) catalyst in a stirred reactor was studied to produce “fuel like” hydrocarbons. The effect of process parameters such as degradation temperature, catalyst/polymer ratio (%), carrier gas type and stirrer rate on the condensed product yield and composition were determined. Reaction products were determined by GC analysis and shown to contain naphthenes, paraffins, olefins and aromatics. Temperature was shown to influence PP cracking. The addition of the catalyst has improved the economic viability of the process to produce light hydrocarbons. PP pyrolysis showed the maximum condensed product yields at 450 °C and 10% catalyst respectively. Hydrogen as a reactive carrier gas increased the condensed and paraffinic product yield. The results showed that reactive carrier gases can affect on the product yield and composition patently. Appropriate heat transfer – by stirring – can increase the catalyst efficiency in a stirred reactor. [ABSTRACT FROM AUTHOR]

The formation of liquid intermediates and the distribution of products were studied under slow and fast pyrolysis conditions. Results indicate that monomers are formed from lignin oligomeric products during secondary reactions, rather than directly from the native lignin. Lignin from Douglas-fir (Pseudotsuga menziesii) wood was extracted using the milled wood enzyme lignin isolation method. Slow pyrolysis using a microscope with hot-stage captured the liquid formation (>150 °C), shrinking, swelling (foaming), and evaporation behavior of lignin intermediates. The activation energy (E a) for 5–80% conversions was 213 kJ mol−1, and the pre-exponential factor (log A) was 24.34. Fast pyrolysis tests in a wire mesh reactor were conducted (300–650 °C). The formation of the liquid intermediate was visualized with a fast speed camera (250 Hz), showing the existence of three well defined steps: formation of lignin liquid intermediates, foaming and liquid intermediate swelling, and evaporation and droplet shrinking. GC/MS and UV-Fluorescence of the mesh reactor condensate revealed lignin oligomer formation but no mono-phenols were seen. An increase in pyrolytic lignin yield was observed as temperature increased. The molar mass determined by ESI-MS was not affected by pyrolysis temperature. SEM of the char showed a smooth surface with holes, evidence of a liquid intermediate with foaming; bursting from these foams could be responsible for the removal of lignin oligomers. Py-GC/MS studies showed the highest yield of guaiacol compounds at 450–550 °C. [ABSTRACT FROM AUTHOR]

• Corrugated cardboard (CCB) was evaluated as a potential feedstock for energy recovery • Pyrolysis of the CCB was carried in an auger reactor (350, 400, and 450 °C) • Pyrolysis biochar and bio-oil yields were temperature dependent • Pyrolysis bio-oil mainly contained lipids and levoglucosan. As the most abundant municipal solid waste, corrugated cardboard (CCB) is a suitable resource for thermochemical conversion into various solid and liquid products. CCB samples were pyrolyzed at three temperatures (350, 400, and 450 °C) and their pyrolysis products (bio-oil and biochar) were characterized and analyzed. Thermogravimetric analysis (TGA) was utilized to study the thermal degradation behavior of CCB. CCB and biochar samples were subjected to proximate, ultimate, lipid and carbohydrates analyses, and Py–GCMS to characterize their chemical components. The highest biochar yield was 75% at 350 °C, and the highest bio-oil yield was 47% at 450 °C. The biochar physical and chemical properties were also assessed using calorific values, specific surface area, Fourier-transform infrared (FTIR) and Raman spectroscopies, and x-ray diffraction (XRD). Biochar was found to have low ash and nitrogen contents. The bio-oil was characterized by the combination of GCMS, high-performance liquid chromatography (HPLC), and electrospray ionization mass spectrometry (ESI–MS). The molar mass distribution and an estimate of monomer/oligomer ratio were determined from ESI-MS data. The bio-oil contained a complex mixture of pyrans, furans, phenols, and cyclopentenes. Levoglucoson was abundantly found in the bio-oil, suggesting the suitability of cardboard pyrolysis products for further processing into fuels. [ABSTRACT FROM AUTHOR]