Effects Of Pyrolysis Parameters Research Articles

A critical re‐analysis of biochar properties prediction from production parameters and elemental analysis

AbstractBiochar is the product of intentional pyrolysis of organic feedstocks. It is made under controlled conditions in order to achieve desired physico‐chemical characteristics. These characteristics ultimately affect biochar properties as a soil amendment. When biochar is used for carbon storage, an important property is its persistence in soil, often described by the proportion of biochar carbon remaining in soil after a 100 years (). We analyzed published data on 1230 biochars to re‐evaluate the effect of pyrolysis parameters on biochar characteristics and the possibility to predict from the maximum temperature reached during pyrolysis (HTT). We showed that biochar ash and nitrogen (N) contents were mostly affected by feedstock type. The oxygen to carbon (O:C) and hydrogen to carbon (H:C) ratios were mostly affected by the extent of pyrolysis (a combination of HTT and pyrolysis duration), except for non (ligno)cellulosic feedstocks (plastic waste, sewage sludge). The volatile matter (VM) content was affected by both feedstock type and the extent of pyrolysis. We demonstrated that HTT is the main driver of H:C ‐‐ an indicator of persistence ‐‐ but that it is not measured accurately enough to precisely predict H:C, let alone persistence. We examined the equations to estimate available in the literature and showed that calculated from HTT presented little agreement with calculated from H:C. The sign and magnitude of the bias depended on the equation used to calculate and the dispersion was usually large. This could lead to improper compensation of carbon emissions and wrong reporting of carbon sinks in national carbon accounting schemes. We recommend not to use HTT as a predictor for persistence and stress the importance to rapidly develop more accurate proxies of biochar C persistence in soil.

Effect of pyrolysis parameters on the biochar reactivity in the N-absorption reaction of chemical looping ammonia generation

Biochar from slow pyrolysis was applied to Chemical Looping Ammonia Generation (CLAG) to avoid the preparation of ammonia from fossil fuels and relatively expensive H2. The effects of pyrolysis atmosphere, temperature, heating rate, and residence time on the biochar reactivity in the N-adsorption reaction were investigated. The relationship between specific surface area, average pore diameter, micropore percentage, and disorder degree of biochar on reactivity was evaluated by simple and multiple linear regression and Analysis of Variance (ANOVA). The results showed that the biochar prepared in a CO2 atmosphere with a pyrolysis temperature of 700 °C, a heating rate of 10 °C/min, and a resident time of 30 min had the highest conversion rate of 57.79 % in the N-absorption reaction. When the pyrolysis temperature was increased from 600 °C to 700 °C, the biochar conversion in the N-adsorption reaction was significantly increased due to the Boudouard reaction during biomass pyrolysis. The linear regression and ANOVA results show that the micropore percentage and disorder degree of biochar significantly positively affected the reactivity, guiding feedstock selection and optimization of the preparation method of the carbon source used for CLAG.

Intermediate pyrolysis of Ficus nitida wood in a fixed-bed reactor: effect of pyrolysis parameters on bio-oil and bio-char yields and properties

Intermediate pyrolysis of Ficus nitida wood in a fixed-bed reactor: effect of pyrolysis parameters on bio-oil and bio-char yields and properties

Fast Pyrolysis of Tea Bush, Walnut Shell, and Pine Cone Mixture: Effect of Pyrolysis Parameters on Pyrolysis Crop Yields

Liquid products obtained by the fast pyrolysis process applied to biomass can be used as chemical raw materials and liquid fuels. In this study, tea bush, walnut shell, and pine cone samples selected as biomass samples were obtained from Trabzon and Rize provinces in the Eastern Black Sea Region and used. When considered in terms of our region, the available biomass waste samples are easy to access and have a high potential in quantity. To employ them in the experimental investigation, these biomass samples were first ground, sieved to a particle size of 1.0 mm, and mixed. A fast pyrolysis process was applied to this obtained biomass mixture in a fixed-bed pyrolysis reactor. The effects of temperature, heating rate, and nitrogen flow rate on the product yields of the fast pyrolysis technique used on the biomass mixture are examined. A constant particle size of 1.0 mm, temperatures of 300, 400, 500, 600, and 750 °C, heating rates of 100, 250, 400, and 600 °C.min−1, and flow rates of 50, 100, 200, and 300 cm3.min−1 were used in tests on fast pyrolysis. The studies showed the 500 °C pyrolysis temperature, 100 °C min−1 heating rate, and 50 cm3.min−1 nitrogen flow rate gave the maximum liquid product yield. The liquid product generated under the most compelling circumstances is analyzed to determine moisture, calorific value, fixed carbon, ash, raw coke, and volatile matter. Additionally, the crude bio-oil heating value, measured at 5900 cal/g and produced under the most favorable pyrolysis circumstances, rose by around 40% compared to its starting material. The liquid product obtained from rapid pyrolysis experiments can be used as liquid fuel. The evaluation of the potential of chemical raw materials can be a subject of research in a different discipline since there are many chemical raw materials (glycerine, furfurals, cellulose and derivatives, carbonaceous materials, and so forth) in fast pyrolysis liquids.

Insights into the effects of pyrolysis parameters on biochar synthesis from green wastes and its As(III) removal efficiency

Insights into the effects of pyrolysis parameters on biochar synthesis from green wastes and its As(III) removal efficiency

Aromatics production from segmented co-pyrolysis of poplar sawdust and high-density polyethylene: Enhancing the synergistic effects

Catalytic co-pyrolysis of biomass and plastic waste is a promising approach for producing renewable biofuels and value-added chemicals. However, because of their different pyrolysis behaviors, the synergy between biomass and plastic is limited, and low-yield aromatics are produced. Herein, a modified segmented catalytic co-pyrolysis technology was proposed, and the effects of pyrolysis parameters were studied in detail to enhance the synergistic effect between feedstocks. For the biomass section (segment 1), catalytic fast pyrolysis (CFP) of poplar sawdust was conducted, and results showed that employing 15 wt% MgCl2 at 500 °C facilitated the production of furans. For the plastic section (segment 2), CFP of high-density polyethylene (HDPE) were performed. It was showed that instead of Y and beta zeolites, the utilization of ZSM-5 as a pyrolysis catalyst with a loading of ZSM-5/HDPE = 1.0, and a temperature of 600 °C was beneficial for the production of short-chain olefins. For the segmented co-pyrolysis of poplar sawdust and HDPE (segment 1 + segment 2), the biomass-to-plastic ratio was crucial in aromatics production. A ratio of 1:1 was found to be most effective in producing MAHs (54.8 area%), which was ∼3.9 or 1.6 times that for the separate CFP of biomass or HDPE. This was also consistent with its higher enhancement factor, confirming that the synergy between poplar sawdust and HDPE was dramatically enhanced. Finally, a segmented catalytic co-pyrolysis reaction pathway was proposed.

Effect of pyrolysis parameters on mechanical properties of polymer-derived ceramics

Polymer-derived ceramics (PDCs) which are fabricated through pyrolysis of preceramic polymers have attracted increasing attention due to their versatility in structure architecture design and property tailoring. Shaping at the polymer state using 3D printing allows the final ceramic products to exhibit arbitrary shapes and complex architectures that are otherwise impossible to achieve through traditional processing routes. The polymer-to-ceramic phase transition also provides additional space for mechanical property tailoring. A multiscale computational model is developed to explore the phase transition mechanisms and their correlations with processing parameters and failure response. Calculations in this work concern PMHS/DVB preceramic polymers. Molecular dynamics (MD) simulations are carried out first to track the atomic structure evolution at different temperatures. Continuum-scale ceramic phase formation is calculated on the basis of the competition between gas generation and gas diffusion. The effect of processing parameters on mechanical properties of pyrolyzed PMHS/DVB is systematically studied. Conclusions from this study can provide direct guidance for fabricating PDC composites with tailored mechanical properties.

Adsorption of Ni(II) on detoxified chromite ore processing residue using citrus peel as reductive mediator: Adsorbent preparation, kinetics, isotherm, and thermodynamics analysis

Chromite ore processing residue (COPR) is a kind of hazardous industrial solid waste produced in the chromium salt industry that needs to be disposed of properly and safely. In this work, an agricultural waste of citrus peel (CP) was used to detoxify COPR by the pyrolysis process, and the resulted residue (DT-COPR) was used as the adsorbent to treat simulated nickel ion (Ni2+) wastewater. The effects of pyrolysis parameters on the COPR detoxification efficiency and adsorption performance of Ni2+ were investigated simultaneously. Besides, operating parameters on the adsorption efficiency and capacity of Ni2+ were also studied and the adsorption kinetics and equilibrium isotherms were summarized correspondingly. The results show not only water-soluble but also insoluble (Cr(Ⅵ)) in the COPR can be effectively reduced by the pyrolysis process, and the total Cr(Ⅵ) decreased from 1641.98 mg/kg to 8.04 mg/kg that can be used safely as an adsorbent. The characterization results of DT-COPR also show that the new adsorbent exhibits good thermal stability and full of chemical functional groups, and adsorption equilibrium of nearly up to 100% of Ni2+ removal efficiency with DT-COPR was achieved within 10–60 min. The adsorption process of Ni2+ can be accurately described by the pseudo-second-order model and Langmuir isotherm, and the theoretical maximum adsorption capacity (qmax) for Ni2+ could reach as high as 18.18 mg/g. This study provided an alternative treatment of bio-safety disposal and resource-oriented utilization of the COPR.

Effects of pyrolysis parameters on physicochemical properties of biochar and bio-oil and application in asphalt.

Adoption of renewable energy sources such as biomass has been increasing worldwide. In this study, fast pyrolysis as an acceptable and viable method to get renewable bio-oil and biochar is used. Different temperatures and N2 flow velocities were used in the fast pyrolysis process to evaluate the pyrolysis yield of biochar and bio-oil. The waste wood and pig manure were utilized to prepare biochar and bio-oil. X-ray fluorescence, X-ray diffraction, high-pressure liquid chromatograph, Micro confocal laser Raman spectrometer, Fourier transform infrared spectrometer, and dynamic shear rheometer were used to measure the chemical compositions, structure, and pyrolysis yield of biochar and bio-oil. The obtained results indicate that pyrolysis temperature increases the purity of inorganic oxide in biochar and N2 flow velocity promotes the yield of carbon in biochar. The increase of N2 flow velocity would increase the acid property of bio-oil and damage the products yield of bio-oil. It was also observed that biochar could remarkably alter the fundamental performances of petroleum asphalt including penetration, softening point, ductility, viscosity, and complex modulus. The most important is that the upgraded bio-oil can be used to replace partly or fully the petroleum asphalt which is a promising biomass application.

Effects of pyrolysis parameters on the distribution of pyrolysis products of Miscanthus

This work presents a comprehensive study on the effects of pyrolysis parameters (pyrolysis temperature, residence time, and heating rate) on the distribution of pyrolysis products of Miscanthus. Py-GC/MS (Pyrolysis-gas chromatography/mass) was conducted to identify building blocks of value-added chemical from Miscanthus. The results showed that the main pyrolysis products of Miscanthus were ketone, aldehyde, phenol, heterocycles, and aromatic compounds. The representative compounds of ketone and aldehyde compounds produced at different pyrolysis temperatures changed obviously, while the representative compounds of phenolic, heterocyclic, and aromatic compounds had no obvious change. Large-scale pyrolysis of Miscanthus had begun at 400°C, and the relative content of pyrolysis products from Miscanthus reached the maximum of 98.34% at 700°C. The relative peak area ratio of phenol and aromatic compounds reached the maximum and minimum at the residence time of 5 and 10 s, while the relative peak area ratio of ketone compounds showed the opposite trend. The relative peak area ratio of aldehyde compounds was higher under shorter or longer residence time. For heterocyclic compounds, the relative peak area ratio reached the maximum of 27.0% at residence time of 10 s. The faster or slower heating rate was beneficial to the production of aldehyde and phenol compounds. The relative peak area ratio of ketone compounds reached the maximum at 10,000°C/s, 70°C/s, and 10°C/s, and the relative peak area ratio tendency of heterocyclic compounds was similar to ketone. For aromatic compounds, the overall fluctuations were large, and the relative peak area ratio was the highest at the heating rate of 100°C/s.

Pyrolysis of coconut cloth in a microwave reactor: Effect of pyrolysis parameters on product yield and characterization of liquid product and biochar

Pyrolysis of coconut cloth was investigated with the influence of pyrolysis process parameters on the maximum products yield and their chemical compositions. With the microwave reactor, the process parameters were as follows: temperature (450 °C to 650 °C), heating rate (10 °C/min to 30 °C/min), and nitrogen flow rate (80 °C/min to 120 cm3/min). The highest liquid yield of 38.3% was observed at 550 °C for the heating rate of 20 °C/min. The characteristics of bio-oil and biochar were analyzed using chromatographic and spectroscopic techniques, such as nuclear magnetic resonance spectroscopy (HNMR), Fourier transformed infrared spectroscopy (FTIR), gas chromatography-mass spectroscopy (GC-MS), scanning electron microscopy-energy dispersive X-Ray (SEM-EDX), X-ray powder diffraction (XRD), and elemental analysis. The bio-oil contained a higher amount of phenolic compounds at 79.6%. The obtained biochar had a calorific value of 27.8 MJ/kg, which made it a promising candidate for solid fuel.

Investigation of the production of pyrolytic bio-oil from water hyacinth (Eichhornia crassipes) in a fixed bed reactor using pyrolysis process

An investigation on the effect of pyrolysis parameters on the yield of pyrolytic bio-oil in the thermal degradation of water hyacinth was studied in a fixed bed reactor. The study revealed that maximum bio-oil yield of 44.5 wt % was realized at a reactor temperature, biomass particle size and nitrogen gas flow rate of 450 °C, 0.6 mm and 100 cm3/min, respectively. GC-MS analysis of the bio-oil detected phenols, alcohols, carboxylic acids, ketones, alkenes, alkanes, aldehydes and aromatics, which envisages that pyrolysis of water hyacinth could be a viable route for the production of renewable fuels and chemicals; and solve the problems of its invasions in our inland fresh water ways.

A Sustainable Process for the Recovery of Anode and Cathode Materials Derived from Spent Lithium-Ion Batteries

The recovery of cathode and anode materials plays an important role in the recycling process of spent lithium-ion batteries (LIBs). Organic binders reduce the liberation efficiency and flotation efficiency of electrode materials derived from spent LIBs. In this study, pyrolysis technology is used to improve the recovery of cathode and anode materials from spent LIBs by removing organic binders. Pyrolysis characteristics of organics in electrode materials are investigated, and on this basis, the effects of pyrolysis parameters on the liberation efficiency of electrode materials are studied. Afterwards, flotation technology is used to separate cathode material from anode material. The results indicate that the optimum liberation efficiency of electrode materials is obtained at a pyrolysis temperature of 500 °C, a pyrolysis time of 15 min and a pyrolysis heating rate of 10 °C/min. At this time, the liberation efficiency of cathode materials is 98.23% and the liberation efficiency of anode materials is 98.89%. Phase characteristics of electrode materials cannot be changed under these pyrolysis conditions. Ultrasonic cleaning was used to remove pyrolytic residues to further improve the flotation efficiency of electrode materials. The cathode material grade was up to 93.89% with a recovery of 96.88% in the flotation process.

Biofuel production via the pyrolysis of sugarcane (Saccharum officinarum L.) leaves: Characterization of the optimal conditions

Sugarcane leaves, a lightweight lignocellulosic biomass from a harvested crop, represent a feedstock for in situ pyrolysis to biofuels and valuable chemicals, facilitating the collection and transportation of pyrolyzed oil to industry. In this paper, the pyrolyzed products were separated into water/aqueous and bio-oil fractions, and the yield was characterized. Pyrolysis was performed in a screw-driven custom-built pyrolysis reactor. The effects of pyrolysis parameters, including the temperature (400–650 °C), feedstock feed rate (0.3–1.8 kg h−1), average size distribution (250 µm, 500 µm and 750 µm) and N2 sweeping gas flow rate (80–240 cm3 min−1) were investigated systematically. The results show that the temperature and residence time according to the N2 sweep gas also mainly affects the bio-oil yield and properties such as the acidity, heating value, viscosity and chemical composition, with the highest bio-oil yield (40.16 wt%) obtained at 500 °C, a feed rate of 0.4 kg h−1, an average biomass feedstock particle size of 500 µm, and an inert N2 flow rate of 120 cm3 min−1. Gas chromatography-mass spectrometry analysis of the chemical composition revealed aromatic derivatives, phenols, ketones, and oxygenated compounds of high molecular weight that might be useful chemical products. These results indicate that pyrolyzed oil cannot be utilized as a biofuel directly but instead must be pretreated. The oil should be treated by a co-catalytic pyrolysis process to be considered a potential source for energy and valuable chemicals. In addition, the biochar was analyzed to determine whether it can be used for the production of activated carbon.

Effects of pyrolysis parameters on the yield and properties of biochar from pelletized sunflower husk

Pyrolysis of biomass residues from agriculture and food processing industry allows production of biochars with diverse physical and chemical properties for a wide range of applications in agriculture and environmental protection. Biochars produced from pelletized sunflower husks through slow pyrolysis in the range of temperatures (480–580°C) showed total carbon of 70.53%–81.96%, total nitrogen of 1.2%, alkaline pH (9.37–10.32), low surface area (0.93–2.91 m2 g-1) and porosity of 13.23–15.43%. Higher pyrolysis temperatures resulted in lower biochar yields. With the increase in temperature the content of organic matter, nitrogen, Ca and Mg decreased whereas the increase in temperature resulted in higher contents of total carbon and phosphorus. Produced biochars showed potential for agricultural applications.

Ceria on alumina support for catalytic pyrolysis of Pavlova sp. microalgae to high-quality bio-oils

In this work, we report for the first time the in-situ catalytic pyrolysis of Pavlova sp. microalgae, which has been performed in a fixed-bed reactor in presence of Ce/Al2O3-based catalysts. The effects of pyrolysis parameters, such as temperature and catalyst were studied on the products yield distribution and bio-oil composition, among others. Results showed that all catalysts increased the bio-oil yield with respect to the non-catalytic runs and reduced the O/C ratio from 0.69 (Pavlova sp.) to 0.1–0.15, which is close to that of crude oil. In terms of bio-oil oxygen content, MgCe/Al2O3 presented the best performance with a reduction of more than 30%, from 14.1 to 9.8 wt%, of the oxygen concentration in comparison with thermal pyrolysis. However, NiCe/Al2O3 gave rise to the highest aliphatics/aromatics fractions. The elemental and gas analysis indicates that N was partially removed from the catalytic bio-oils in the gas phase in forms of NH3 and HCN.

Pyrolysis of giant mullein (Verbascum thapsus L.) in a fixed-bed reactor: Effects of pyrolysis parameters on product yields and character

ABSTRACTSlow pyrolysis of giant mullein (Verbascum thapsus L.) stalks have been carried out in a fixed-bed tubular reactor with (Al2O3, ZnO) and without catalyst at four different temperatures between 400 to 550°C with a constant heating rate of 50°C/min and with a constant sweeping gas (N2) flow rate of 100 cm3/min. The amounts of bio-char, bio-oil, and gas produced were calculated and the compositions of the obtained bio-oils were determined by gas chromatography-mass spectrometry. The effects of pyrolysis parameters, such as temperature and catalyst, on the product yields were investigated. The results show that both temperature and catalyst have significant effects on the conversion of Verbascum thapsus L. into solid, liquid, and gaseous products. The highest liquid yield of 40.43% by weight including the aqeous phase was obtained with 10% zinc oxide catalyst at 500°C temperature. Sixty-seven different products were identified by gas chromatography-mass spectrometry in the bio-oils obtained at 500°C temperature.

Solar pyrolysis of beech wood: Effects of pyrolysis parameters on the product distribution and gas product composition

The solar pyrolysis of beech wood was investigated with the objective of determining the optimal pyrolysis parameters for maximizing the LHVs (lower heating values) of the gas products because they can be further utilized as fuel gas for power generation, heat and production of transportable fuels. The investigated variables were the pyrolysis temperature (600–2000 °C), heating rate (5–450 °C/s), argon flow rate (6–12 NL/min) and pressure (0.44–1.14 bar). The results indicate that the product yields (liquid, char and gas), gas composition (H2, CH4, CO, CO2 and C2H6) and LHV are strongly influenced by the pyrolysis parameters. The total gas LHV greatly increases with increasing temperature (from 600 to 1200 °C) and increasing heating rate (from 5 to 50 °C/s), which is mainly due to increases in the CO and H2 yields. The variation in the gas LHV with pressure and argon flow rate is slight. A maximum gas production of 62% with a LHV of 10 376 ± 218 (kJ/kg of wood) is obtained under solar pyrolysis conditions of 1200 °C, 50 °C/s, 0.85 bar and 12 NL/min. This heating value is almost identical to that of the initial beech wood, thus confirming that valuable combustible gases can be produced via the solar pyrolysis of beech wood.

Slow pyrolysis of paulownia wood: Effects of pyrolysis parameters on product yields and bio-oil characterization

Pyrolysis experiments of paulownia wood (P. tomentose) were performed in a fixed-bed reactor under static and nitrogen atmospheres. The effects of the final pyrolysis temperature (623–873K), heating rate (10 and 50Kmin−1), particle size (0.224–1.8mm), and sweep gas flow rate (100–300mLmin−1) were investigated on the pyrolysis conversion and product yields. The maximum pyrolysis conversion of 77.4% was obtained at a final pyrolysis temperature of 773K. The highest liquid product yield of 54.0wt% was obtained at the pyrolysis temperature of 773K with a heating rate of 50Kmin−1, particle size of 0.425<Dp<1mm and a nitrogen flow rate of 100mLmin−1. In addition, the bio-oil and fractions of the bio-oil were examined using elemental analysis and, chromatographic and spectroscopic techniques. The empirical formula of the bio-oil with heating value of 28.6MJkg−1 was established as CH1.57O0.29. The obtained bio-oil can be considered a potential source for energy or fuels and a valuable chemical feedstock.

Catalytic pyrolysis of liquorice (Glycyrrhiza glabra L.) in a fixed-bed reactor: Effects of pyrolysis parameters on product yields and character

Pyrolysis of liquorice (Glycyrrhiza glabra L.) stalks were performed in a fixed-bed tubular reactor with (ZnO, FeCl3, K2CO3, Al2O3, Na2B4O7·10H2O) and without catalyst at three different temperatures (350, 450, 550°C) with a constant heating rate of 40°C/min. The amounts of bio-char, bio-oil and gas produced, as well as the compositions of the resulting bio-oils were determined by GC–MS. The effects of pyrolysis parameters on product yields were investigated. The results indicate that both temperature and catalysts effect the conversions of G. glabra L. into solid, liquid and gaseous products. The highest conversion of 74.50% and liquid yield of 34.35% were obtained with Na2B4O7·10H2O catalyst at 550°C temperature when 0.224>Dp>0.150mm particle sized samples and 100mL/min of sweeping gas flow rate were used. Liquid products (bio-oils) obtained at 350 and 550°C were analyzed by elemental analysis and gas chromatography/mass spectrometry (GC–MS). 133 and 148 different compounds were identified by GC–MS in the bio-oils obtained at 350 and 550°C, respectively.