Optimum Pyrolysis Conditions Research Articles

Confirmation of the feasibility of using agrobyproduct biochar in thermal power plants through oxygen pyrolysis and conventional pyrolysis

This study investigates the feasibility of utilizing agrobyproduct biochar as a substitute for fossil fuels in thermal power plants by comparing oxygen-rich and oxygen-lean pyrolysis processes. The biomass types examined include soybean pods (BE), bamboo (BB), and wood pellets (WP). Results demonstrate that oxygen-lean pyrolysis at high temperatures enhances biochar's carbon content and energy density. Mass yields varied, with WP showing the highest yield at 500℃ under oxygen-lean conditions. Elemental analysis indicated increased carbon content and improved fuel properties with higher pyrolysis temperatures. Proximate composition analysis revealed decreased volatile matter and increased fixed carbon and ash content, leading to higher fuel ratios. Calorific values increased significantly across all biomasses, particularly under oxygen-lean conditions. Gas analysis showed significant changes in O2, CO2, and CO concentrations with temperature variations. Combustion indices and physical properties like aromaticity and Hardgrove grindability index improved with higher temperatures. Optimal pyrolysis conditions were identified as 325℃ for WP, 350℃ for BB, and 300℃ for BE, with BE also performing well at 500℃. The study concludes that optimized agrobyproduct biochar can effectively replace conventional fossil fuels, offering high energy yield and enhanced combustion properties.

Soil utilization analysis of synergistic pyrolysis products of flue gas desulfurization gypsum and biomass

Flue gas desulfurization gypsum (FGDG) is one of the typical bulk solid wastes. With its vast production and considerable storage capacity, it accumulates in substantial quantities, occupies an extensive amount of land, and poses a severe pollutant threat to the ecological environment. To achieve large-scale consumption of FGDG, this study puts forward a method for the soil utilization and ecological reconstruction involving the co-pyrolysis of FGDG and biomass. The main emphasis is placed on exploring the alterations in leaching toxicity and plant-available elements under diverse conditions of temperature, biomass addition, and pyrolysis time. The co-pyrolysis parameters were optimized, and the changes in mineral composition of FGDG and biomass under different pyrolysis circumstances were investigated using XRD and SEM characterization methods. The experimental outcomes demonstrated that the optimal pyrolysis conditions were a temperature of 700 °C, a biomass content of 60 %, and a pyrolysis time of 5 h. The toxic and harmful substances within FGDG were solidified and stabilized, achieving a harmless treatment of FGDG. Simultaneously, the usable elements for plants were released. Through the analysis of mineral composition and microstructure, it was discovered that the pyrolysis products contain a considerable amount of CaSO4 and C, and the microstructure mainly consists of porous aggregates. The reason for the reduced leaching efficiency of toxic and harmful substances might be attributed to the formation of stable minerals such as heavy metals through crystallization and vitrification mineralization after the removal of crystal water from FGDG. Under the reduction effect of C, the available elements for plants are liberated. This study furnishes a theoretical basis for the industrial application of FGDG and biomass for large-scale soil utilization treatment.

Highly efficient and eco-friendly process for selective recovery of copper from waste printed circuit boards via pyrolysis and ammoniacal solvoleaching

This study proposes a process combining pyrolysis and ammoniacal solvoleaching to selectively recover Cu from waste printed circuit boards (WPCBs). Optimal pyrolysis conditions were determined by investigating parameters such as temperature, heating rate, N2 flow rate, holding time and particle size. Under the conditions: 500 °C temperature, 20 °C/min heating rate, 0.3 L/min N2 flow rate, 10 min time and +9.50 mm particle size, ∼25% of weight loss was obtained. The pyrolyzed mass underwent further physical separation process involving impact crushing, magnetic- and gravity separations to enrich metals into a concentrate. Copper in the resulting concentrate was selectively extracted using a one-stage ammoniacal leaching and solvent extraction process (ammoniacal solvoleaching), employing an oxime-based organic extractant, LIX 84-I with a small volume of NH4OH. Ammoniacal solvoleaching was optimized by considering parameters such as stirring speed, time, LIX 84-I concentration, volume of aqueous ammonia, temperature and pulp density. Under the following conditions: 500 rpm, 0.3/0.3/10 (g/mL/mL) of sample/NH4OH/LIX 84-I (0.8 M), 3 h time and 25 °C temperature, quantitative Cu dissolution was achieved after two-stage solvoleaching. Cu solvoleaching followed the Avrami model, with an activation energy of 28.95 kJ/mol in the temperature range 15–45 °C (298–318 K) for the mixed control mechanism. LIX 84-I could be recycled without loss of extraction performance. Cu concentration was further enriched during stripping stage using H2SO4. A flowsheet for the sustainable metal recovery from WPCBs was developed.

Extraction and volatilization mechanism of germanium (Ge) during lignite pyrolysis

Germanium is a critical strategic metal that plays an important role in various industries. Currently, the combustion method is the main method for extracting germanium from germanium-containing lignite, however, its extraction rate of germanium is low, with the form of SiO2-GeO2 solid solution due to covolatilization of both germanium and arsenic. To address these problems, this paper proposes to activate and enrich germanium in lignite through pyrolysis. The results show that the pyrolysis temperature and time are positively correlated with the volatilization rate of germanium, and the optimal pyrolysis conditions are at temperature of 1100°C with the time of 360 min. The volatility of germanium can reach up to 96.85%, and its grade in germanium-rich product is 25.51%, while arsenic content is 0.71%. The germanium-rich product is primarily present as GeS, with no SiO2-GeO2 solid solution, which is conducive to the subsequent chlorinated distillation. The kinetics and thermodynamics of the pyrolysis process are investigated, and the volatilization of germanium during lignite pyrolysis is modeled. These results verify the feasibility of germanium extraction from lignite by pyrolysis, which anticipates to realize the high-grade enrichment of germanium in lignite and the high-value utilization of lignite resources.

Co-pyrolysis of cellulose and lignin: Effects of pyrolysis temperature, residence time, and lignin percentage on the properties of biochar using response surface methodology

Cellulose, hemicellulose, and lignin constitute the basic components of biomass. Knowledge of the interactions between cellulose and lignin during pyrolysis is crucial for unraveling the pyrolysis characteristics of biomass. In this study, for the co-pyrolysis of cellulose and lignin to produce biochar, three influencing factors were selected: pyrolysis temperature (400–800 °C), residence time (5–30 min), and lignin percentage (0–100 %). Pyrolysis experiments were conducted in a vertical tube furnace and the impact of these three factors on the characteristics of biochar was comprehensively explored employing response surface methodology. The results revealed obvious differences between actual values and theoretical values. Specifically, the results showed that the interaction between cellulose and lignin increased the biochar yield, oxygen content, volatile content, and ash content by 6.14 %, 22.85 %, 30.95 %, and 46.75 %, respectively. In contrast, the carbon content, fixed carbon content, and HHV of biochar were relatively reduced by 9.38 %, 11.80 %, and 3.3 %, respectively. Furthermore, Raman spectra of biochar showed that the actual value of graphitization degree of biochar was higher than the theoretical value. This was further corroborated by XPS analysis, wherein owing to the interactions between cellulose and lignin, the actual C-C bond content decreased in contrast to the theoretical value. However, the contents of C-O, CO, COOH functional groups, and aromatic rings increased. Finally, the summary of the co-pyrolysis rules of cellulose and lignin provided a reference for optimal pyrolysis conditions and understanding the mechanism of co-pyrolysis.

Predictive capability of rough set machine learning in tetracycline adsorption using biochar

Machine learning algorithms investigate relationships in data to deliver useful outputs. However, past models required complete datasets as a prerequisite. In this study, rough set-based machine learning was applied using real-world incomplete datasets to generate a prediction model of biochar’s adsorption capacity based on key attributes. The predictive model consists of if–then rules classifying properties by fulfilling certain conditions. The rules generated from both complete and incomplete datasets exhibit high certainty and coverage, along with scientific coherence. Based on the complete dataset model, optimal pyrolysis conditions, biomass characteristics and adsorption conditions were identified to maximize tetracycline adsorption capacity (> 200 mg/g) by biochar. This study demonstrates the capabilities of rough set-based machine learning using incomplete practical real-world data without compromising key features. The approach can generate valid predictive models even with missing values in datasets. Overall, the preliminary results show promise for applying rough set machine learning to real-world, incomplete data for generating biomass and biochar predictive models. However, further refinement and testing are warranted before practical implementation.

Eco-innovation in energy: Solid degradation kinetics of rejected red macroalgae (Kappaphycopsis cottonii) for bio-oil and biochar production

In the pursuit of renewable energy sources, biomass conversion into biofuels has garnered attention as a sustainable alternative to fossil fuels. This research focuses on the pyrolytic conversion of red macroalgae, specifically rejected Kappaphycus cottonii, an underutilized biomass in Indonesia, into valuable bio-energy carriers, while analyzing the solid degradation kinetics involved. The dried K. cottonii underwent slow pyrolysis at varying temperatures (400–600 °C) and time intervals (10–50 min). The impact of these variables on the yield of bio-oil and biochar, alongside the thermogravimetric profiles indicating mass loss, was thoroughly assessed. The study also explores the chemical kinetics of the decomposition process, utilizing the first-order reaction model to analyze the solid biomass conversion rate, activation energy, and frequency factor. Key findings demonstrate that the optimal pyrolysis temperature for maximizing bio-oil yield was precisely 500 °C, beyond which thermal cracking led to yield reductions. Reaction times also greatly affect yield, highlighting the importance of optimized pyrolysis conditions. The determined activation energy and frequency factor, based on the Arrhenius equation, highlighted K. cottonii's lower decomposition energy barrier relative to terrestrial biomass. This distinction is largely ascribed to its unique chemical makeup, notably a lower lignin content, positioning K. cottonii as an advantageous feedstock for biofuel production through pyrolysis.

Study on Pyrolysis Characteristics of Phosphate Tailings under H2O Atmosphere.

The pyrolysis separation of calcium and magnesium from phosphate tailings is an important process due to its high-value resource utilization. In this paper, aiming to address the problems of high energy consumption, a slow decomposition rate and the low activity of decomposition products in the high-temperature pyrolysis of phosphate tailings, the medium-temperature pyrolysis of phosphate tailings under a H2O atmosphere was carried out, and the phase reconstruction and activation of pyrolysis process were discussed. The results showed that compared with N2, air and CO2 atmospheres, the pyrolysis process of phosphate tailings in a H2O atmosphere was changed from two stages to one stage, the starting decomposition temperature was reduced to 500 °C and the decomposition time was shortened to 30 min. The order of the influence of each factor on the pyrolysis of phosphate tailings was temperature > H2O pressure > holding time. Under the optimized pyrolysis conditions, the yield of CaMg(CO3)2 decomposition of phosphate tailings into MgO and CaO was 97.3% and 98.1%, respectively, and the reactivity of MgO was 31.6%. The distribution of Ca and Mg elements in the phosphate tailings after pyrolysis showed a negative correlation, and both of them no longer formed associated compounds; Ca mainly existed in the form of Ca(OH)2, Ca5(PO4)3F, CaSiO3 and CaF2, and Mg mainly existed in the form of MgO, MgF2 and Mg(OH)2.

The relevant effect of marine salt and epiphytes on Posidonia oceanica waste pyrolysis: Removal of SO2/HCl emissions and promotion of O/HCOOH formation

Significant quantities of Posidonia oceanica deposit on some beaches and coastlines every year, which generates high costs associated with the disposal of this waste. Pyrolysis may be an adequate way for its valorization. However, it would imply to know how the process takes place and if the removal of its natural detrital inorganic matter (epiphytes, marine salt and sand) is necessary, which are the objectives of this research. Pyrolysis by thermogravimetry-mass spectrometry was carried out on both the washed and unwashed samples.During this waste pyrolysis, the following occurs: (i) the high alkali metal chloride content promotes fragmentation reactions of carbohydrates and O formation, which increases HCOOH intensities at temperatures between 250 and 360 °C; (ii) from 500 °C to 650 °C, Fe2O3 and decomposition of carbonates seem to be involved in reactions that produce O release and steam and CO2 reforming of hydrocarbons and oxygenated organic compounds with H2 generation; (iii) from 650 °C to 750 °C, Fe2O3, high alkali metal content and carbonate decomposition generate char gasification, an increase in O release, SO2 capture and HCOOH formation.In general, the abundance of inorganic matter (chlorides, carbonates, etc.) minimizes the release of various compounds during pyrolysis, including SO2 and HCl, while increasing HCOOH production. Thus, this high content of inorganic matter may represent an advantage for its pyrolysis, producing value-added chemical products with a reduced environmental impact. Therefore, this study may be the starting point for defining the optimal pyrolysis conditions for this waste valorisation.

Assessing coconut shell pyrolysis: Biomass characterization, activation energy estimation, and statistical analysis of operating conditions

This study experimentally investigates the conventional pyrolysis of green coconut shell (GCS) in a fixed-bed reactor, analyzing operational conditions and their impact on product yields using statistical methods. Comprehensive characterization of GCS highlighted an extractive content of 36.65 %, significantly influencing the pyrolysis activation energy. Statistical analysis revealed that temperature has a more pronounced effect on yield over particle size. Optimal pyrolysis conditions were identified at 773.15 K with a particle diameter of 1.3 mm, achieving a maximum bio-oil yield of 49.45 %, surpassing the reported in previous fixed-bed reactor studies. Bio-oil analysis indicated aldehydes, phenols, and esters predominance, with temperature as the primary factor influencing their formation. The study demonstrates the effectiveness of GCS pyrolysis in fixed bed reactors for converting waste into valuable products with potential applications as energy sources, as well as in the chemical and pharmaceutical industries, thereby reducing environmental impacts associated with improper disposal.

Detailed studies on characterization and photocatalytic hydrogen production of ammonium tetrathiomolybdate and tetrathiotungstate pyrolysis products

MoS2 and WS2 are two promising candidates for photocatalytic hydrogen production, and pyrolysis is one of the conventional and useful methods for their preparations. However, systematic investigations about the influences of pyrolysis conditions on their photocatalytic hydrogen production performances are still unreported. Then in this paper, a series of pyrolysis products of ammonium tetrathiomolybdate (ATM) and ammonium tetrathiotungstate (ATT) were prepared by changing the pyrolysis temperature and time. Besides, detailed characterizations were conducted to find out the changes in composition, crystallinity, and morphology. Especially, to get optimal pyrolysis conditions for the preparation of high-performance MoS2 and WS2, their photocatalytic hydrogen production activities were investigated. The results showed that although along with the changes in pyrolysis conditions, the overall changes in composition, crystallinity and morphology are similar for ATM and ATT products, there are significant differences in their performances. For the pyrolysis of ATM, the products obtained under lower temperatures exhibit relatively higher activity than those obtained under higher temperatures. The performance of sample ATM-400-1 (the pyrolysis product obtained under 400 °C 1 h) is the highest and those of two ATM-600 samples (obtained under 600 °C 1 h and 600 °C 2 h) are the lowest. On the contrary, for the pyrolysis of ATT, the higher-temperature products possess much higher performance than the lower-temperature ones. The activity of ATT-400-2 is the highest and those of two ATT-250 samples are the lowest. On the other hand, unconventional crystallized WS3 was unexpectedly obtained through the pyrolysis of ATT at 300 °C for the first time. This work can offer useful information for the preparation of WS2 and MoS2-based photocatalysts.

Application of Artificial Neural Network (ANN) as a predictive tool for the removal of pharmaceutical from wastewater streams using biochar: a multifunctional technology for environment sustainability

This study investigates biochar as an attractive option for removing pharmaceuticals from wastewater streams utilizing data from various literature sources and also explores the sensitivity of the characteristics and implementation of biochar. ANN 1 was designed to determine the optimal biochar characteristics (Surface Area, Pore Volume) to achieve the maximum percentage removal of pharmaceuticals in wastewater streams. ANN 2 was developed to identify the optimal biomass feedstock composition, pyrolysis conditions (temperature and time), and chemical activation (acid or base) to produce the optimal biochar from ANN 1. ANN 3 was developed to investigate the effectiveness of the biochar produced in ANN 1 and 2 in removing dye from water. Biomass feedstock with a high lignin content and high volatile matter at a high pyrolysis temperature, whether using an acid or base, achieves a high mesopore volume and high surface area. The biochar with the highest surface area and mesopore volume achieved the highest removal percentage. Regardless of hydrophobicity conditions, at low dosages (0.2), a high surface area and pore volume are required for a high percent removal. And with a higher dosage, a lower surface area and pore volume is necessary to achieve a high percent removal.

Optimum pyrolysis conditions to prepare the most crystalline boron carbide powder from boric acid-mannitol complex ester.

A weak acidic complex ester (CE) in solid form was prepared by a condensation reaction between very weak boric acid (BA: H3BO3) and (D)-mannitol (MA: C6H14O6) by the molar ratio of BA/MA = 2. A boron carbide (B4C) precursor was obtained from heating of the CE at 400 °C for 4 h. The precursor was pyrolyzed under argon flow in the interval of 1300-1550 °C for 4 h and at 1400 °C for 1-4 h, respectively. The materials were examined using several techniques such as X-ray diffraction analysis, thermal analysis, scanning electron microscopy, particle size distribution, and nitrogen adsorption/desorption. The optimum pyrolysis temperature and duration were 1400 °C and 4 h, respectively. The most crystalline B4C particles were distributed between 1 and 100 μm with a mean particle size of 20 μm. The specific surface area and specific pore volume were 13.5 m2 g-1 and 0.09 cm3 g-1, respectively. The size of the pores was between 2 and 36 nm with a mean size of 14 nm.

Production of High-Porosity Biochar from Rice Husk by the Microwave Pyrolysis Process

This study focused on the highly efficient pyrolysis of rice husk (RH) for producing high-porosity biochar at above 450 °C under various microwave output powers (300–1000 W) and residence times (5–15 min). The findings showed that the maximal calorific value (i.e., 19.89 MJ/kg) can be obtained at the mildest microwave conditions of 300 W when holding for 5 min, giving a moderate enhancement factor (117.4%, or the ratio of 19.89 MJ/kg to 16.94 MJ/kg). However, the physical properties (i.e., surface area, pore volume, and pore size distribution) of the RH-based biochar products significantly increased as the microwave output power increased from 300 to 1000 W, but they declined at longer residence times of 5 min to 15 min when applying a microwave output power of 1000 W. In this work, it was concluded that the optimal microwave pyrolysis conditions for producing high-porosity biochar should be operated at 1000 W, holding for 5 min. The maximal pore properties (i.e., BET surface area of 172.04 m2/g and total pore volume of 0.1229 cm3/g) can be achieved in the resulting biochar products with both the microporous and the mesoporous features. On the other hand, the chemical characteristics of the RH-based biochar products were analyzed by using Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDS), displaying some functional complexes containing carbon–oxygen (C–O), carbon–hydrogen (C–H), and silicon–oxygen (Si–O) bonds on the surface of the RH-based biochar.

A Comprehensive Review in Microwave Pyrolysis of Biomass, Syngas Production and Utilisation

Lignocellulosic and waste materials, such as sewage sludge, can be broken down into its useful constituents and converted into fuel for engines. This paper investigates microwave pyrolysis to decompose biomass into H2 and CO (syngas), which may be catalysed in the Fischer–Tropsch (F-T) process to liquid biofuels. Using microwave radiation as the heat source for pyrolysis proves to yield large quantities of gas with higher concentrations of H2 and CO compared to conventional heating methods. This is largely due to the energy transfer mechanism of microwaves. Pyrolysis parameters such as temperature (which increases with input power), feedstock type, microwave absorber, and biomass moisture content influence syngas yield. Several papers reviewed for this study showed differing optimal conditions for microwave pyrolysis, all being heavily dependent on the biomass used and its composition. However, all researchers agreed on the thermal efficiency of microwave heating and how its material-selective nature can increase syngas yield. Compared to diesel fuels (while processing a similar efficiency and a higher cetane number), FT fuels and specifically pyrolysis may yield the benefit of reduced nitric oxides (NOx), particulate matter (PM), unburnt hydrocarbons (HC) and carbon monoxide (CO) emissions.

A promising method for the liberation and separation of solar cells from damaged crystalline silicon photovoltaic modules

Reasonable and efficient recycling of waste crystalline silicon (c-Si) photovoltaic (PV) modules benefits environmental protection and resource conservation. The liberation and separation of solar cells in modules is the key to achieving effective recycling. The recovery of intact waste modules has been studied by some scholars, but few have specifically examined damaged modules. This study focused on modules that have been broken during transportation, installation, use, or disassembly. Two liberation methods, mechanical crushing and pyrolysis were compared from the perspectives of particle size distribution and morphological characteristics of products. In addition, for separating glass particles and solar cells of coarse fraction, an environmentally-friendly technology of gas-solid fluidized bed was introduced based on their shape and density difference. The effects of airflow velocity and fluidizing time on separation efficiency were investigated for different size fractions. Results showed that pyrolysis was a more suitable liberationliberation method for damaged modules. Higher liberation efficiency could be obtained by pyrolysis, and over-crushing of glass particles and solar cells could be avoided. The optimum pyrolysis conditions were found to be at 500 °C with a holding time of 30 min. The recovery and concentration of solar cells in the >4 mm size fraction were 91.09% and 84.4%, respectively, under the following conditions: 85 m3/h airflow velocity; 90s fluidizing time. For the 2–4 mm size fraction, the recovery and concentration were 82.29% and 80.52% under airflow velocity of 75 m3/h, fluidizing time of 90s. This research presents an alternative process for recovering damaged c-Si PV modules.

Pyrolysis behaviour of shellfish waste via TG-FTIR and Py-GC/MS

Shellfish waste (SW), a by-product of seafood processing and consumption, poses ecological concerns from improper management, resulting adverse effects such as water pollution, habitat degradation, and destruction of local ecosystems. Furthermore, the inefficient disposal of SW goes against the principles of circular economy and resource utilization. Therefore, this study is conducted to convert and reuse SW and transform it into value-added products, thereby contributing to sustainable waste management practices. Shellfish waste was characterized for its elemental and proximate contents, followed by performing pyrolysis of SW to study the pyrolysis behaviors and chemical composition of pyrolytic products. Thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TG-FTIR) was employed to identify the optimal pyrolysis temperature range (660–780 °C). Additionally, pyrolysis combined with gas chromatography/mass spectrometry (Py-GC/MS) was utilized to analyze gaseous products generated from SW pyrolysis. The analysis revealed that SW possesses a low high calorific value (5.57–8.05 MJ/kg) and high H/C (0.3–1.3) and O/C (3.2–5.2) ratios, rendering it unsuitable for direct use as fuel. Optimal pyrolysis conditions were identified within the temperature range of 660–780 °C through TG-FTIR analysis. Py-GC/MS analysis at 700 °C and a heating rate of 30 °C/min indicated that carboxyl compounds (37.3–87.0%) constituted the dominant components of gaseous products generated during SW pyrolysis. In conclusion, the study underscores the promise of pyrolysis as a viable method for transforming SW into value-added chemicals. The findings of this study contribute to the advancement of sustainable waste management strategies and the utilization of waste materials for valuable purposes in various industries.

Bromine Migration and Product Analysis of Waste Printed Circuit Boards during Microwave Steam‐Gasification‐Assisted Pyrolysis

AbstractBromine in waste printed circuit boards has caused serious harm to the environment. How to deal with it safely is a problem. In this paper, the debromination of waste printed circuit boards by microwave gasification pyrolysis was studied, and the properties of pyrolysis products and the migration of bromine were analyzed. The optimum pyrolysis conditions of microwave steam atmosphere were 600 °C, 1000 W, 50 min, 2 mL/min. Compared with conventional pyrolysis and conventional steam pyrolysis, less solid products (60.39 wt %) were obtained, and more metal copper was enriched. The content increased from 27.46 % and 28.35 % to 30.63 %, respectively, and the diffraction peak intensity of copper was also enhanced. There is no obvious change in the type of functional groups of the solid product, and its microscopic morphology is smoother. Compared with conventional pyrolysis, the phenolic compounds in pyrolysis oil decreased, and increased compared with conventional steam pyrolysis. The content of H2 in the pyrolysis gas increased significantly, and the content of CO decreased significantly. Compared with conventional pyrolysis, the bromine content in pyrolysis gas and pyrolysis oil decreased from 94.5 % and 5.5 % to 1 %, respectively, and more bromine (98 %) in the raw material entered the aqueous solution.

Penentuan Suhu Optimum Pirolisis Serbuk Gergaji Batang Kelapa

Research has been carried out on the utilization of biomass waste of coconut trunk sawdust using the pyrolysis method to produce two products simultaneously, namely charcoal and liquid smoke. In order to obtain charcoal products with optimum calorific value, it is necessary to understand the optimum pyrolysis conditions. One of the optimum conditions, namely pyrolysis temperature, was studied in this research. Pyrolysis was carried out in a simultaneous pyrolysis reactor at a flow rate of argon inert gas into the reactor of 2 liters/minute and a pyrolysis time of 2.5 hours with pyrolysis temperature variations of 350, 400, 450, and 500°C, respectively. The study showed that the optimum temperature of 400oC was obtained which gave a yield of 34% charcoal with a calorific value of 7229 kcal/kg. Compared to the calorific value of the raw material for coconut sawdust which is 4400 kcal/kg, there was an increase in the calorific value of the pyrolysis product by 64%. Based on the optimum temperature condition, liquid smoke as a by-product was also obtained with a yield of 45%. Charcoal can be used as a solid fuel or as a bioadsorbent in the treatment of liquid waste or clarification of liquid food products such as virgin coconut oil (VCO). Grade 3 liquid smoke can be used as a biopesticide, while grade 1 liquid smoke can be used as a food preservative. Given the benefits of the two pyrolysis products, both of the products from the current research have a promising market value.

Performance assessment of drop tube reactor for biomass fast pyrolysis using process simulator

AbstractBiomass pyrolysis process from a drop tube reactor was modelled in a plug flow reactor using Aspen Plus process simulation software. A kinetic mechanism for pyrolysis was developed considering the recent improvements and updated kinetic schemes to account for different content of cellulose, hemicellulose, and lignin. In this regard, oak, beechwood, rice straw, and cassava stalk biomasses were analyzed. The main phenomena governing the pyrolysis process are identified in terms of the characteristic times. Pyrolysis process was found to be reaction rate controlled. Effects of pyrolysis temperature on bio‐oil, gases, and char yields were evaluated. At optimum pyrolysis conditions (i.e., 500°C), a bio‐oil yield of 67.3, 64, 43, and 52 wt.% were obtained from oak, beechwood, rice straw, and cassava stalk, respectively. Oak and beechwood were found to give high yields of bio‐oil, while rice straw produced high gas and char yields compared to other biomasses. Although temperature is the main factor that plays a key role in the distribution of pyrolysis products, the composition of cellulose, hemicellulose, and lignin in the feedstock also determines the yield behaviour and composition of products. With the rise in pyrolysis temperature, further decomposition of intermediate components was initiated favouring the formation of lighter fractions. Comparably, species belonging to the aldehyde chemical family had the highest share of bio‐oil components in all the investigated feedstocks. Overall, the present study shows a good agreement with the experimental study reported in the literature, confirming its validity as a predictive tool for the biomass pyrolysis process.