Pyrolysis bio-oil as a renewable fuel and source of chemicals: its production, characterization and stability

Bio-oil is a liquid fuel that can be produced from various lignocellulosic feedstocks via fast pyrolysis. It is a complex mixture comprised of hundreds of highly oxygenated organic compounds originating from lignin and carbohydrates and is recognized as a clean renewable bio-fuel, an attractive alternative to fossil fuels. It can be easily transported and used directly in boilers and modified turbines or upgraded/fractionated for drop in fuels or chemical production. Proper bio-oil characterization is important in optimizing the pyrolysis process, bio-oil upgrading and utilization, and its stabilization for long-term storage. With this in mind, research has been undertaken to develop better techniques to rapidly profile the composition of whole bio-oil samples, and an accelerated aging study performed to determine why bio-oil is unstable upon storage. Pyrolysis-GC/MS and TLC-FID were used as tools to differentiate bio-oils of different lignocellulosic biomasses, and among thermal-cracking (upgrading) fractions. Results showed that birch bio-oil had high syringol derivatives compared to pine and barley straw bio-oils which had higher guaiacol and non-methoxy-phenolic compounds, respectively, compared with birch bio-oil. TLC-FID was successful in bio-oil differentiation, showing diagnostic chromatographic profile differences. Direct infusion-ESI-ion trap MS and ESI-ion trap MS2 were successfully used in the analysis of forest-residue bio-oil and reference bio-oils from cellulose and hardwood lignin dissolved in methanol:water. NH4Cl can be used as a dopant to distinguish carbohydrate-derived products from other bio-oil components. NaOH and NaCl dopants resulted in the highest intensity peaks in negative ion mode and positive mode, respectively. Tandem MS, that is, ESI-Ion Trap MS2 was a successful tool for the confirmation of individual target ions such as levoglucosan and cellobiosan and for structural insight into lignin products. In accelerated aging (at 80 °C for 1, 3 and 7 days) studies, the physical and chemical properties of bio-oil from ash wood (produced from a pilot-scale auger pyrolyzer) and birch wood (lab-scale pyrolyzer) were monitored in order to identify the factors responsible for bio-oil instability. Water content, viscosity, and decomposition temperature (by TGA) increased for both bio-oil samples with aging. Chemical analysis showed reduction in amount of most of the bio-oil components as aging progressed, typically for are olefins and aldehydes. The oils remained a single phase throughout until the 7th day

Direct Infusion Mass Spectrometric Analysis of Bio-oil Using ESI-Ion-Trap MS

Direct infusion-electrospray ionization (ESI)-Ion-Trap MS and ESI-Ion-Trap MS² were used for direct analysis of bio-oil from forest residue and reference bio-oils from cellulose and hardwood lignin. It was found that the bio-oil concentration and mode of MS analysis are important parameters in obtaining reproducible and structurally informative data. In order to study sensitivity and selectivity with ESI-Ion-Trap MS, a selection of model compounds were studied with and without dopants. Dopants included NaCl, formic acid and NH₄Cl in positive ion mode and NaOH and NH₄Cl in negative ion mode. NH₄Cl addition can be used to distinguish carbohydrate-derived products from other bio-oil components. NaOH and NaCl additives produced the highest peak intensities in negative ion mode as deprotonated adducts and in positive mode as sodiated adducts, respectively. ESI-MS² was used successfully for confirmation of individual target ions such as levoglucosan and cellobiosan, as well for some structural products of lignin. Simple bio-oil fractionation into hydrophilic and hydrophobic components provided less complex and more interpretive ion spectra

Extraction and characterization of Cucumis melon seeds (Muskmelon seed oil) biodiesel and studying its blends impact on performance, combustion, and emission characteristics in an internal combustion engine

This study examines the performance, combustion, and emissions characteristics of a single-cylinder internal combustion diesel engine when fueled with a blend of diesel and biodiesel derived from muskmelon seeds. The kinematic viscosity of the extracted muskmelon seed oil was 6.1 cSt at 40 °C, which is higher than the kinematic viscosity of petroleum diesel of 2.6 cSt. Muskmelon biodiesel was further analyzed using thin-layer chromatography (TLC) and high-voltage separator tests. A comparison of the fuel properties of muskmelon biodiesel with conventional diesel fuel revealed that muskmelon biodiesel could be used alone or in a diesel–biodiesel blend to fuel compression diesel engines. In this study, muskmelon seed biodiesel was blended with diesel fuel at proportions of 10 %, 20 %, and 50 % (BD10, BD20, and BD50, respectively). At a relatively low rotational speed of 1200 rpm, the brake thermal efficiency (BTE) of the engine operated with BD10 and BD20 blends were 36.1 % and 36.0 %, respectively, while the brake-specific fuel consumption (BSFC) of the two blends were 0.260 kg/kWh, and 0.262 kg/kWh, respectively. These values closely resemble those typically observed in diesel fuel engines. Indeed, the average BTE of the BD20 blend was only 3.24 % less than the average BTE of diesel fuel. Diesel fuel generates less NOx and SO2 emissions compared to biodiesel blends: BD100 emitted the most NOx pollution of all fuels tested. In addition, BD10 released significantly more SO2 emissions compared to the other fuels tested. However, the BD20 blend outperformed all other blends in terms of CO, NOx, and SO2 emissions at high engine speeds. The only exception was H2S emissions, which were higher than BD50 and BD100. BD20 also exhibited significantly reduced CO emissions compared to diesel fuel, while BD10 emitted significantly more CO emissions than the other biodiesel blends. Our findings revealed that BD20 exhibited the best engine performance and lower emissions among all fuels tested. In other words, BD20 is the ideal fuel blend for use in diesel engines and does not require any alterations to the engine. Muskmelon waste seeds represent a non-edible waste stream that can be exploited in the production of biodiesel fuel, allowing for the upcycling of a potentially problematic thermochemical conversion feedstock. This potentially valuable use for waste muskmelon seeds in the energy sector could address the wastefulness associated with this particular waste stream