Chemical Composition Of Bio-oil Research Articles

Hydrothermal Pyrolysis of Sargassum Marine Macroalgae: "Synthesis and Characterization of Products"

Abstract In recent years, there has been an explosive growth and overabundance of pelagic Sargassum macroalgae in the North Atlantic Ocean, which wash up on the beaches in the United States, Mexico and the Caribbeans, causing both environmental and health issues in those coastal regions. Hydrothermal carbonization (HTC) process was investigated as a potential solution by converting this wet algae biomass into solid and liquid products, namely hydrochar and organic process water, respectively. In this study, the effects of HTC reaction temperatures on the yields and physicochemical properties of hydrochar and organic process water derived from Sargassum algae sample obtained from a coastal region in South Florida were evaluated by using various analytical techniques, including SEM, TGA, BET, FTIR and GC-MS. As a result of the increase in temperature, hydrochar yield decreased, while the yield of bio-oil increased. During the heating process, the volatile matter in hydrochar decreases, whereas the fixed carbon increases. Ash content in hydrochar increases as temperature increases. There were some interconnected pores on the surfaces of all three temperatures. It has been shown that a change in temperature has a significant effect on the chemical composition of bio-oils. In some cases, certain compounds increased as the temperature increased, but in others, it was temperature dependent. This study demonstrated that HTC technology could be a potential solution for mitigating Sargassum pollution issue by converting it into value-added bio-based products.

Microwave pyrolysis of sewage sludge for bio-oil production: Effects of organic components and mechanisms

The microwave pyrolysis (MWP) of sewage sludge (SS) was conducted to investigate the impact of the organic composition of SS on the yield and composition of the derived bio-oil. The experiments were conducted in a microwave oven at 900 °C with a heating rate of 50 °C/min and achieved the product yield of 43.10 ± 2.23% bio-oil, 48.07 ± 1.26% bio-char, 8.83 ± 1.65% bio-gas. The chemical composition of bio-oil was investigated using gas chromatography–mass spectrometry and 145 species were identified. Protein and lipid contents in SS are the primary source of bio-oil yield, while bio-gas are predominantly derived from lignocellulosic materials. The unique non-thermal effects of microwaves can facilitate the ring-opening of small cycloalkanes to form straight olefins through hydrogen transfer reactions. Additionally, they can promote aldol condensation reactions, Pinacol rearrangements, and methoxy cleavage to form phenolic and aromatic structures with methyl groups. Furthermore, microwaves can aid in the dehydration, condensation, and cyclization reactions of amino acids to produce N-heterocycles while also facilitating lipid depolymerization into fragments for Diels–Alder cyclization. The results of this study will be beneficial for deeply understanding reactant characteristics and the reaction process during the MWP of SS.

Quantitative Low-Field 19 F Nuclear Magnetic Resonance Analysis of Carbonyl Groups in Pyrolysis Oils.

Pyrolysis bio-oils, one of the products of lignocellulosic biomass pyrolysis, have the potential to be widely used as fuels. The chemical composition of bio-oils is very complicated as they contain hundreds, if not thousands, of different, mostly oxygen-containing, compounds with a wide distribution of physical properties, chemical structures, and concentrations. Detailed knowledge of bio-oil composition is crucial for optimizing both the pyrolysis processes and for any subsequent upgrading into a more viable fuel resource. Here we report the successful use of low-field, or benchtop, nuclear magnetic resonance (NMR) spectrometers in the analysis of pyrolysis oils. Pyrolysis oils from four different feedstocks were derivatized and analyzed using 19 F NMR techniques. The NMR results compare favorably with titrations for total carbonyl content. In addition, the benchtop NMR spectrometer proves able to reveal key spectral features, thus allowing the quantification of different carbonyl groups, such as aldehydes, ketones and quinones. Benchtop NMR spectrometers are typically compact, cheaper than their superconducting counterparts and do not require cryogens. Their use will make NMR analysis of pyrolysis oils easier and more accessible to a wide range of different potential users.

Influence of sodium hypochlorite/ultrasonic pretreatment on sewage sludge and subsequent hydrothermal liquefaction: Study on reaction mechanism and properties of bio-oil

Subcritical hydrothermal liquefaction (HTL) is an efficient approach for bio-oil production from wet sewage sludge (SS). Before HTL, pretreatment of wet SS by sodium hypochlorite (NaClO) or combination of NaClO and ultrasonic treatment was implemented with different NaClO dosage or ultrasonic temperature for the first time. The results demonstrated that TOC and content of protein in EPS of SS increased after two pretreatment methods. Meanwhile, the bio-oil yield was improved and the maximum of 39.4 wt% was obtained from the bio-oil under combined pretreatment (9.39 mg NaClO/g dried SS and ultrasounds at 80 °C) when HTL was performed at 300 °C for 15 min. Additionally, the maximum energy recovery reached 58.0% with the highest carbon recovery (61.9%) and the highest hydrogen recovery (39.0%) in bio-oils obtained from HTL of combined pretreated SS. GC-MS and NMR analysis showed that the chemical compositions of bio-oil were not affected significantly by pretreatment methods but relative percentage of each compound was changed. The esters formation was favored after combined pretreatment and increased to 16.3%, while the contents of acids and N-containing compounds decreased by 8.2% and 4.0%, respectively. TGA of bio-oils revealed that both pretreatments could promote the formation of light oil components such as diesel. Finally, the main possible reaction pathways for HTL of SS have been elucidated. Overall, this research provided a theoretical foundation for utilization of wet SS from sewage treatment plant directly for bioenergy production.

Understanding the synergistic effect during co-liquefaction of cellulose and hemicellulose (xylan) in subcritical water

Hydrothermal liquefaction (HTL) is a promising technology for conversion lignocellulosic biomass into bio-oil, however, the interactions between biomass components are not well understood. Microcrystalline cellulose (MCC) and xylan were used as model components for cellulose and hemicellulose in the HTL process considering the influence of temperature, reaction time and solvent to solid ratio. Synergistic interactions occurring between MCC and xylan could enhance both the bio-oil and heavy bio-oil (HBO) yields, and MCC contributed more to the oil yield. In terms of HBO yield, it was in the order of MCC (20.8%) > MCC-xylan (19.4%) > xylan (17.5%). Regarding to the bio-oil chemical compositions, interactions promoted the formation of 5-hydroxymethylfurfural and inhibited some carbonyl groups. Higher temperatures led to lower H/C and O/C of the HBO from MCC-xylan, which also increased the HHV of HBO. The synergies identified in this work provide new insight into potential interactions between biomass components.

Improving the Bio-Oil Quality of Residual Biomass Pyrolysis by Chemical Activation: Effect of Alkalis and Acid Pre-Treatment

In this study, we investigated the acid (HCl) and alkali (KOH) chemical activation of açaí seeds (Euterpe Oleraceae, Mart.) pre-treatment before pyrolysis at temperatures of 350–450 °C in order to assess how reactions proceed when affected by temperature. Chemical composition of bio-oil and aqueous phase were determined by GC-MS and FT-IR. The bio-char is characterized by XRD. For the activation with KOH, the XRD analysis identified the presence of Kalicinite (KHCO3), the dominant crystalline phase in bio-char, while an amorphous phase was identified in bio-chars for the activation with HCl. The experiments have shown that bio-oil yield increases with temperature for the KOH activated biomass and decreases for the acid activated one. The KOH bio-oil is primarily composed of alcohols and ketones, showing the lowest acid values when compared with the HCl one, which is composed mainly of carboxylic acids and phenols. An increase in alcohol content and a decrease in ketones in the KOH bio-oil with temperature suggests conversion reactions between these two functions. For HCl bio-oil, carboxylic acid concentration increases with temperature while phenols decrease. For production of hydrocarbons, KOH activated biomass pyrolysis is better than acid-activated one, since no hydrocarbons were produced for HCl bio-oil.

Characterization of Adansonia Digitata (Baobab Wood) Bio‑Oil and Biochar Produced Using a Fixed-Bed Tubular Reactor

The investigation of the characterization of Adansonia digitata biomass from pyrolysis in a fixed-bed tubular carbon steel reactor at temperatures of 400℃ to 700℃. Firstly, proximate, ultimate, and heating value analyses of the raw biomass were obtained prior to experimental runs via the fast pyrolysis process; thereafter, the quality of the bio-oil and biochar yields for bioenergy and industrial applications was investigated using the following analyses: higher heating values (HHV), lower heating values (LHV), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). Optimum bio-oil (52.70 wt%) and bio-char (40 wt%) yields were obtained at temperatures of 500 and 400℃, respectively. GC-MS analysis of the yielded biooil revealed a higher percentage of oleic acid, phenol, methanol, and ketone among the fuel compositions, whereas the bio-oil chemical composition includes carbon (70.99%), hydrogen (13.40%), nitrogen (0.54%), oxygen (15.01%), and sulfur (0.06%), flash (81) and pour points (-7) for bio-oil with HHV (30.75 MJ/kg) and LHV (27). The results obtained demonstrated that the properties of products can serve as a waste management strategy, sorbent, soil enhancer, and biofuel industry application.

Catalytic Upgrading of Plastic Waste of Electric and Electronic Equipment (WEEE) Pyrolysis Vapors over Si–Al Ash Pellets in a Two-Stage Reactor

This study investigated thermal cracking and catalytic upgrading of waste from electric and electronic equipment (WEEE) plastics on a semi-batch reactor coupled to a heated catalyst fixed bed (2-stage vapor cracking). The catalyst used is a Si–Al ash obtained from commercial activated carbon pellets treated with concentrated NaOH solution and calcination. The purpose of the study was to characterize the waste stream through its thermogravimetry analysis and pyrolysis products, study the effect of temperature (350–500 °C) and catalyst quantity (0.0–7.5 %.wt) on yields of reaction products, physical chemical properties, and chemical composition of bio-oil in order to understand and evaluate production of fuels and chemical feedstock by recycling of WEEE plastic through catalytic upgrading. Time-fractioned samples were taken in determined reaction times (15, 30, 45, and 60 min) to study the evolution of cracking reactions during experiment runs through changes to chemical composition (GC/MS). A comparison with other previous work is also presented to show similarities between different feedstocks using the same thermal unit. The results indicate composition of brominated acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC), and high impact polystyrene (HIPS) for the WEEE plastic. The temperature of 350 °C produced better results when considering acid value but presented lower bio-oil yields (38%) and high gas yields (42%). Catalytic upgrading experiments revealed the increased presence of polycyclic aromatic hydrocarbons (PAH) with an increase in viscosity of bio-oil, increase in char yield (from 11% to 24%), and decrease in gas yields (15% to 5%). Chemical composition showed presence of aromatic hydrocarbons such as styrene, methyl-styrene, and diphenyl-propane and nitrogenated compounds such as benzene-butane-nitrile, phenolic compounds, PAHs, and brominated compounds. WEEE plastic pyrolysis is a challenging subject due to contaminant presence and varying composition, and chemical composition evaluation according to reaction time provides interesting insights into the evolution of semi-batch pyrolysis/catalytic upgrading experiments. Standardization and reproducibility of the tool should be conducted to continue the evaluation of pyrolysis and catalytic upgrading of a wide range of feedstocks.

Response surface optimization of product yields and biofuel quality during fast hydrothermal liquefaction of a highly CO2-tolerant microalgae

The effects of biochemical components and processing variables (e.g., temperatures, solid-liquid ratio, ethanol concentration, and time) during fast hydrothermal liquefaction of a highly CO2-tolerant microalgae (Micractinium sp.) on the product yields and biofuel quality were explored using response surface methodology coupled with central composite design. Results showed that the maximum bio-oil yield (51.4 %) was obtained at 321 °C for 49 min at ethanol concentration of 75 % and solid-liquid ratio of 15.3 %. Among different studied parameters, ethanol concentration showed the highest significant impact on the bio-oil yield due to the low P-value and high F-value in ANOVA analysis. Furthermore, the chemical compositions of bio-oils were determined, which showed that the increase of ethanol concentration in the solvent not only increased the bio-oil yield but also promoted the bio-oil quality by reduction of carboxylic acids and nitrogen-containing compounds with simultaneous enhancement of esters in the bio-oil. The present results show that fast hydrothermal liquefaction is a promising approach to convert the microalgae into high quality biofuels rich in esters.

A Systematic Approach to Thermochemical Treatment of Municipal Household Solid Waste into Valuable Products: Analysis of Routes, Gravimetric Analysis, Pre-Treatment of Solid Mixtures, Thermochemical Processes, and Characterization of Bio-Oils and Bio-Adsorbents

This work aims to investigate the effect of process temperature and catalyst content by pyrolysis and thermal catalytic cracking of (organic matter + paper) fraction from municipal household solid waste (MHSW) on the yields of reaction products (bio-oil, bio-char, H2O, and gas), acid value, chemical composition of bio-oils, and characterization of bio-chars in laboratory scale. The collecting sectors of MHSW in the municipality of Belém-Pará-Brazil were chosen based on geographic and socio-economic database. The MHSW collected and transported to the segregation area. The gravimetric analysis of MHSW was carried out and the fractions (Paper, Cardboard, Tetra Pack, Hard Plastic, Soft Plastic, Metal, Glass, Organic Matter, and Inert) were separated. The selected organic matter and paper were submitted to pre-treatment of crushing, drying, and sieving. The experiments carried out at 400, 450, and 475 °C and 1.0 atmosphere, and at 475 °C and 1.0 atmosphere, using 5.0, 10.0, and 15.0% (wt.) Ca(OH)2, in batch mode. The bio-oil was characterized for acid value. The chemical functions present in bio-oil were identified by FT-IR and the composition was identified by GC-MS. The bio-char was characterized by SEM, FT-IR, and XRD. The variance in mass (wt.%) for organic fractions of municipal household solid waste (OFMHSW), between 56.21 and 67.45% (wt.), lies with the interval of 56% (wt.) and 64% (wt.) of OFMHSW for middle- and low-income countries. The pyrolysis of MHSW fraction (organic matter + paper) shows bio-oil yields between 2.63 and 9.41% (wt.), aqueous phase yields between 28.58 and 35.08% (wt.), solid phase yields between 35.29 and 45.75% (wt.), and gas yields between 16.54 and 26.72% (wt.). The bio-oil yield increases with pyrolysis temperature. For the catalytic cracking, the bio-oil and gas yields increase slightly with CaO content, while that of bio-char decreases, and the H2O phase remains constant. The GC-MS of liquid reaction products identified the presence of hydrocarbons (alkanes, alkenes, alkynes, cycloalkanes, and aromatics) and oxygenates (carboxylic acids, ketones, esters, alcohols, phenols, and aldehydes), as well as compounds containing nitrogen, including amides and amines. The acidity of bio-oil decreases with increasing process temperature and with aid Ca(OH)2 as a catalyst. The concentration of hydrocarbons in bio-oil increases with increasing Ca(OH)2-to-OFMHSW fraction ratio due to the catalytic deoxygenation of fatty acid molecules, by means of decarboxylation/decarbonylation, producing aliphatic and aromatic hydrocarbons.

Catalytic Upgrading of Residual Fat Pyrolysis Vapors over Activated Carbon Pellets into Hydrocarbons-like Fuels in a Two-Stage Reactor: Analysis of Hydrocarbons Composition and Physical-Chemistry Properties

This work investigated the influence of the reaction time and catalyst-to-residual fat ratio by catalytic upgrading from pyrolysis vapors of residual fat at 400 °C and 1.0 atmosphere, on the yields of reaction products, physicochemical properties (density, kinematic viscosity, and acid value) and chemical composition of bio-oils, over a catalyst fixed-bed reactor of activated carbon pellets impregnated with 10.0 M NaOH, in semi-pilot scale. The experiments were carried out at 400 °C and 1.0 atmosphere, using a process schema consisting of a thermal cracking reactor of 2.0 L coupled to a catalyst fixed-bed reactor of 53 mL, without catalyst and using 5.0%, 7.5%, and 10.0% (wt.) activated carbon pellets impregnated with 10.0 M NaOH, in batch mode. Results show yields of bio-oil decreasing with increasing catalyst-to-tallow ratio. The GC-MS of liquid reaction products identified the presence of hydrocarbons (alkanes, alkenes, ring-containing alkanes, ring-containing alkenes, and aromatics) and oxygenates (carboxylic acids, ketones, esters, alcohols, and aldehydes). For all the pyrolysis and catalytic cracking experiments, the hydrocarbon selectivity in bio-oil increases with increasing reaction time, while those of oxygenates decrease, reaching concentrations of hydrocarbons up to 95.35% (area).

Properties of Upgraded Bio-oil from Pyrolysis of Waste Corn Cobs

Technologies for conversion of waste solid materials to liquid fuel and bio-crude oil have been researched widely for the production of renewable energy as substitute to fossil fuel oil. However, ash composition of biomass affects the pyrolysis process and the bio-crude oil product has unsatisfactory properties compared to conventional petroleum oil, such as, low heating value, high viscosity, corrosiveness, and the presence of oxygenated compound which causes bio oil ageing. This paper investigated the total waste materials; corn cobs and paper sludge obtained in municipal areas of Abuja, Nigeria, employed in pyrolysis of demineralized corn cobs and the upgrade of crude bio oil via thermal cracking using zeolite prepared from waste paper sludge, with expectation to improve bio oil properties. Demineralization of corn cob removed most of the ash content of biomass allowing for pyrolysis process. The prepared zeolite with mesoporous cage-like crystals analyzed using SEM was able to effectively catalyze thermal cracking of the crude bio oil and reduce the quantity of less desired high molecular weight oxygenated compounds. The bio oil chemical composition obtained from GC-MS analysis indicated the bio oil consisted of oxygenated compounds and hydrocarbons such as aliphatic hydrocarbons (28.768%), alcohols (-0.001%), amines (10.472%), carboxylic acids (0.144), phenols (0.047%), and esters (60.57 %), which significantly influenced the bio oil properties. The physical and chemical properties of the corn cob bio oil was determined for density (0.852 ± 0.03), viscosity (1.66 ± 0.01), cloud point (-34.0 ± 0.02) and calorific value (30.9 ± 0.01). With the exception of Flash point (58 ± 0.01) and acid value (13.1 ± 0.03). In comparison, the produced bio oil had properties likened to petroleum fraction of conventional gasoline than diesel. In conclusion, pyrolysis of corn cob and upgrade of the crude bio oil using prepared zeolite was found as a promising process in improving bio oil quality. The pyrolysis study has potential in the management of environmental wastes to help resolve the challenge of solid waste disposal.

Study of Catalytic Pyrolysis of Biomass Sorghum (Sorghum bicolor L. Moench) Using Design of Experiments and Surface Response Methodology

This study proposes a screen of variables that have an influence on the modification of the bio-oil chemical composition as a unique critical quality attribute (CQA) throughout the pyrolytic process (zeolite, ZSM-5) by using a 24 full factorial design, followed by optimization through a response surface methodology (RSM) based on central composite design (CCD) involving samples of biomass sorghum BRS716 (Sorghum bicolor L. Moench). The pyrolysis of pure biomasses and the biomass impregnated with the catalyst was carried out in a vertical bench furnace at 500 °C. Screening design involved factor variation in two levels (–1 and +1) of four variables as critical process parameters (CPPs) such as furnace heating rate (°C min–1), nitrogen flow (mL min–1), amount of biomass (g), and catalyst (% m/m), leading to obtaining bio-oil. Thus, it was possible to create a response surface from these two variables (biomass and catalyst), in which a minimum critical point was reached. The production of a bio-oil rich in hydrocarbon compounds is possible, but a large amount of catalyst was required. Two analytical techniques based on gas chromatography coupled to mass spectrometry (GC-MS) and mid-infrared (MIR) spectroscopy, provided additional information to fully characterize bio-oil chemical composition.

Valorization of Vine Prunings by Slow Pyrolysis in a Fixed-Bed Reactor

The paper aimed at studying the slow pyrolysis of vine pruning waste in a fixed bed reactor and characterizing the pyrolysis products. Pyrolysis experiments were conducted for 60 min, using CO2 as a carrier gas and oxidizing agent. The distribution of biochar and bio-oil was dependent on variations in heat flux (4244–5777 W/m2), CO2 superficial velocity (0.004–0.008 m/s), and mean size of vegetal material (0.007–0.011 m). Relationships among these factors and process performances in terms of yields of biochar (0.286–0.328) and bio-oil (0.260–0.350), expressed as ratio between the final mass of pyrolysis product and initial mass of vegetal material, and final value of fixed bed temperature (401.1–486.5 °C) were established using a 23 factorial design. Proximate and ultimate analyses, FT-IR and SEM analyses, measurements of bulk density (0.112 ± 0.001 g/cm3), electrical conductivity (0.55 ± 0.03 dS/m), pH (10.35 ± 0.06), and water holding capacity (58.99 ± 14.51%) were performed for biochar. Water content (33.2 ± 1.27%), density (1.027 ± 0.014 g/cm3), pH (3.34 ± 0.02), refractive index (1.3553 ± 0.0027), and iodine value (87.98 ± 4.38 g I2/100 g bio-oil) were measured for bio-oil. Moreover, chemical composition of bio-oil was evaluated using GC-MS analysis, with 27 organic compounds being identified.

Pyrolysis of water buffalo manure: Influence of temperature and alkali hydroxide additives on the quality of bio-oil

In this study, the influence of catalytic and non-catalytic pyrolysis of the water buffalo manure on the physical-chemical characterizations, pyrolysis product yield and chemical composition of bio-oil was studied. The first part of the experiments was performed in a reactor with a diameter of 24 mm and height of 36 cm, running with varying temperature from 350 °C to 550 °C. The highest yield of bio-oil was found 27.6 wt% at 450 °C. After optimum temperature was determined, effects of alkali hydroxides catalysts were investigated. Under the influence of NaOH and KOH used as alkali hydroxide, a reduction in liquid product yield was recorded, while an increase was observed on char and gas yield. The obtained results from elemental analysis depicted that the H/C ratios increased while O/C ratios decreased under the influence of alkali hydroxides catalysts. 1H NMR analysis results showed that aliphatic OH groups constitute the majority of pyrolysis bio-oil. The chemical characterization of bio-oil was conducted by gas chromatography-mass spectrometry (GC-MS). Alkali hydroxides catalysts had important effect on the chemical content, especially hydrocarbons and carboxylic acids. When the catalysts applied, the percent of hydrocarbons increased, on the other hand the percent of carboxylic acids decreased. This research study revealed the potential of bio-oil obtained from water buffalo pyrolysis can be used as a renewable energy source.

Coal gasification fine slags: Investigation of the potential as both microwave adsorbers and catalysts in microwave-induced biomass pyrolysis applications

The coal gasification fine slags (CGFS) are rich in porous carbon and various metal elements (Al, Fe, Ca, Na, K, Mg). In this work, three types of CGFS-based catalysts (CGFS@GSP, CGFS@OMB, and CGFS@TEX) were prepared and used in microwave-induced biomass pyrolysis to investigate the possibility of CGFSs as both microwave absorbing materials and catalysts for synergistic renewable phenols and fuel gas production. The CGFS-based catalysts displayed rough and porous structures, containing a variety of active metals and compounds. Remarkable microwave absorbing ability with higher heating rates than SiC was achieved by the CGFS-based catalysts during biomass pyrolysis. The catalysts showed high activity for biomass pyrolysis under microwave heating conditions, resulted in the increase of gas yield and the decrease of water and bio-oil yields. The bio-oil chemical composition was significantly simplified and was dominated by C3–C10 compounds. Phenols are the dominant component in the produced bio-oil, and the content reached 69.6% and 71.3% using CGFS@OMB and CGFS@TEX as the catalysts. Meanwhile, the gas yield was significant improved by the catalysts at a higher temperature of 650 °C, and the value reached 64.4% using CGFS@OMB as the catalyst with a remarkable hydrogen concentration of 44.9%.

Pyrolysis of sewage sludge for sustainable biofuels and value-added biochar production

The study deals with the pyrolysis of sewage sludge to produce eco-friendly and sustainable fuels along with value-added biochar products. The experiments were conducted in a fixed-bed cylindrical glass reactor in the temperature range of 250–700 °C and achieved the product yield of 22.4 wt% bio-oil, 18.9 wt % pyrolysis gases, and 58.7 wt% biochar at 500 °C optimum temperature. The chemical composition of bio-oil was investigated by gas chromatograph-mass spectroscopy and fourier transformation infrared techniques. The ASTM standard procedures were used to assess the fuel qualities of bio-oil, and they were found to be satisfactory. Bio-oil has a greater H/C ratio (3.49) and a lower O/C ratio (1.10), indicating that it is suitable for engine use. The gas chromatographic analysis of pyrolysis gases confirmed the presence of 41.16 wt % combustible gases, making it suitable for use in spark-ignition engines. X-ray fluorescence analysis of biochar showed that it had a good amount of carbon, nitrogen, phosphorus, and potassium along with some micro-and macro-nutrient which proves its potential to utilize as organic manure in the agriculture sector. In addition, the data obtained from the TGA analysis during the pyrolysis of sewage sludge was applied to calculate kinetic parameters via the Coats-Redfern method.

Investigations in influence of different pretreatments on A. donax pyrolysis: Trends in product yield, distribution and chemical composition

This study explores the influence of chemical pretreatment on the compositional and structural properties of Arundo donax, and the consequent effects on the pyrolysis products with emphasis on chemical composition of bio-oil. A. donax samples were chemically pretreated with different concentrations of 5 media (viz. H2SO4, H3PO4, NaOH, SDS and Triton X-100) and pyrolyzed in a semi-batch pyrolysis reactor. The chemical composition of obtained bio-oils was quantitatively determined by GC–MS analysis. The primary effects of pretreatments were in terms of 10.1–49.2 % enhancement in bio-oil yield in the order: untreated biomass < H2SO4 < Triton X-100 < SDS < H3PO4 < NaOH. Acid treatment, in general, led to an increase in furan production, with H3PO4 treatment yielding the highest furan yield of 21.2 % v/v. GC–MS analysis revealed substantial reduction in oxygenates with alkali treatment. The drop in lignin fraction with all pretreatments led to generation of lower phenol and methoxyphenol bio-oil derivatives except with SDS treatment, which reported high methoxyphenol derivatives content. Although the biochar yield dropped by 11.9–32.9 %, significant improvement in its quality was indicated by lower H/C and O/C ratios and higher calorific value of 27.5–30.5 MJ/kg, which is at par with coal. Non-condensable gas yields dropped post pretreatment of biomass, signifying a favorable shift to production of bio-oil.

Co-pyrolysis of oil palm empty fruit bunch and oil palm frond with low-density polyethylene and polypropylene for bio-oil production

Co-pyrolysis of palm wastes of empty fruit bunch (EFB) and palm frond (PF) with low-density polyethylene (LDPE) and polypropylene (PP) were investigated to find the synergistic effect of biomass-plastic pair on the yield and composition of bio-oil produced. The pyrolysis process of individual materials and their corresponding blends were employed in a fixed bed reactor at heating rate of 20 °C/min with a nitrogen flow rate of 250 mL/min. The co-pyrolysis results showed that EFB:LDPE with weight ratio of 1:1 has the largest synergy on bio-oil yield, while a negative synergy was revealed for PF:PP co-pyrolysis. In regard of bio-oil chemical composition, the synergistic effect was positive for the formation of aliphatic hydrocarbons and all feedstock decreased the overall oxygenated compounds of fuel substitute. The hydrogen generated from plastic promoted the decarboxylation of acids and decarbonylation reactions of carbonyls and sugars.

Liquid bio-fuels and carbon adsorbents production via pyrolysis of non-edible feedstock

The slow pyrolysis of milk thistle (Silybum marianum L.) seeds (MTS) in a lab-scale batch reactor to investigate the influence of heating rate, temperature, contact period, and particle size on the yields of bio-oil (BO) and bio-char (BC) was presented for the first time. The maximum yield of BO (49.55 ± 2.50 %) was obtained at a pyrolysis temperature of 475 °C for 60 min using a 0.25 mm MTS particle size at 20 °C/min heating rate. The chemical composition of BO from MTS was identified by FTIR, 1H NMR, and GC–MS techniques. Following the FTIR outcomes, aldehydes, alcohols, phenols, acids, and alkanes are present in the BO . Also, results from 1H NMR spectrum indicated that the percentage of the aliphatic compounds in the as-synthesized BO was greater than that of the aromatic compounds. The GC–MS analysis exhibited that the MTS derived BO is rich in higher acids (38.64 %), higher esters (21.30 %), and hydrocarbons (11.39 %). The elemental analysis consequences revealed that the attained BO possessed a higher carbon content and a lower oxygen content than its respective MTS with a chemical formula of CH1.67 N0.025O0.10. Additionally, the BO owned a calorific value of 39.47 MJ/kg, close to that established for petro based liquid fuels and comparable to those of BOsamples declared in the literature. Besides, the physic-chemical properties of the MTS derived BO were close to those specified for conventional fossil fuels. Proximate analysis, elemental composition, higher heating value, iodine number, surface area, and morphology of the attained biochar were determined. The ZnCl2 activation method was employed to synthesize activated carbon from the produced BC via the optimized procedure. An impregnation ratio of 1.5:1 ZnCl2:BC, 500 °C, 60 min activation period, and 0.21 mm particle size were the best conditions to yield an activated carbon with 638.66 mg/g iodine number and 677.22 m2/g surface area. The FESEM results affirmed the mesoporosity of the attained activated carbon compared to the macroporosity of the pristineBC .