Utilization of camellia oleifera shell for production of valuable products by pyrolysis

Camellia oleifera shell is used as the feedstock to prepare the valuable products by pyrolysis using microwave heating at 400-800 °C. The yield of pyrolysis product is influenced by pyrolysis temperature, which indicates that high pyrolysis temperature promotes to generate bio-gas and restrains the production of biochar. However, pyrolysis temperature little influences the yield of bio-oil. The main compound of bio-oil is phenols, hydrocarbons, ketones, aldehydes and furans, respectively. While, bio-oil produced at 600 °C has as high as 78 % of phenols, which has potential application in chemical industries. The pyrolysis temperature has significantly influenced the composition and heating value of bio-gas. The maximum heating value of bio-gas is 12.44 MJ/Nm³, which is achieved at 600 °C. The physiochemical properties of biochar are also influenced by pyrolysis temperature. Biochar could be used as an adsorbent to adsorb Ag⁺ from aqueous solution, which is formed the value-added ABiochar composite by reduction. The adsorption and reduction process of Ag⁺ are investigated. While, ABiochar composite can be used as the catalyst for methylene blue degradation. ABiochar composite can be also used in the lithium ion battery cathode material for energy storage.     

Pyrolysis of sorghum bagasse biomass into bio-char and bio-oil products

The transformation of renewable biomass into valuable products as alternatives to fossil fuels is essential for sustainable energy in sustainable society. This work systematically investigates the pyrolysis of sorghum bagasse biomass into bio-char and bio-oil products and studies the effect of temperature (623–823 K) on the conversion of sorghum bagasse and products yields. The physicochemical properties of bio-char were thoroughly studied using powder X-ray diffraction, elemental analysis (CHNSO), scanning electronic microscope, calorific value (CV), and Fourier transform infrared (FTIR) spectroscopy techniques. Also, gas chromatography–mass spectrometry (GC–MS), CV, and FTIR were used to understand the properties of bio-oil. The results obtained indicate that an increase in the pyrolysis temperature from 623 to 823 K leads to a decrease in the bio-char yield from 42.55 to 30.38%. On the other hand, the maximum bio-oil yield of 15.94% was obtained at 723 K. The bio-char obtained at 673 and 773 K was found by FTIR analysis to be composed of a highly ordered aromatic carbon structure. The calorific value of bio-oil, which contains a greater amount of acidic compounds, was found to be 6740 kcal/kg. The GC–MS analyses revealed the presence of octadecenoic acid, p-cresol, 2,6-dimethoxy phenol, 4-ethyl 2-methoxy phenol, phenol, o-guaiacol, and octadecanoic acid in the bio-oil obtained from the pyrolysis of sorghum bagasse biomass. The present study provides useful information for understanding the quality of bio-oil and bio-char obtained from high biomass sorghum bagasse.     

Bio-oil production by flash pyrolysis of sugarcane residues and post treatments of the aqueous phase

The pyrolysis of three sugarcane residues (internal bagasse, external and whole plant) has been carried out in a pilot bubbling fluidized bed pyrolyzer operating under a range of temperature from 300 °C to 600 °C and two vapor residence time (2 and 5 s), with the aim of determining their pyrolysis behavior including products yields and heat balance. The composition of the product gases was determined, from which their heating value was calculated. The liquid bio-oil was recovered with cyclonic condensers and separated into two phases, an aqueous phase and an organic phase. The energy content of the organic phase was determined in comparison with common fossil fuels. Activated carbon adsorption and distillation at 110 °C were used to treat the aqueous phase, with the aim of recovering valuable hydrocarbons and purifying the aqueous phase for wastewater disposal. Furthermore, the thermal sustainability of the pyrolysis process was estimated by considering the energy contribution of the product gases and of the liquid bio-oil in relation to the pyrolysis heat requirements. The optimum pyrolysis temperatures were identified in terms of maximizing the liquid yield, maximizing the energy from the product bio-oil, and maximizing the net energy from the product bio-oil after ensuring a self-sustainable process by utilizing the product gases and part of bio-oil as heat sources.     

Highly fluorescent carbon dots from peanut shells as potential probes for copper ion: The optimization and analysis of the synthetic process

The use of natural materials, a renewable resource, instead of chemicals as carbon precursors for simple synthesis of fluorescent carbon dots (FCDs) remains a significant challenge. Here, we report the preparation of FCDs with a photoluminescence (PL) quantum yield (QY) of 10.58% from peanut shells via one-pot pyrolysis treatment optimized by using a central composite experiment design. Optimum pyrolysis conditions were found to be 400 °C temperature, 4 h duration, and 70 g peanut shell weight. The as-prepared FCDs possess unique excitation-dependent behavior, good water dispersibility and high photostability. The results of Fourier transform infrared (FTIR) spectroscopy to analyze the pyrolytic process indicated the complete combustion of peanut shells happened at 3 and 4 h at 400 °C. The PL intensity of the FCDs was not always proportional to the corresponding QY value in our work due to the different amount of carbon-rich residues after the pyrolysis process. Fluorescence-quenching trials were conducted to analyze their sensitivity and selectivity in Cu²⁺ detection. The detection limit was found to be 4.8 μM. Our pyrolysis treatment of peanut shells for preparing FCDs is not only a green and facile method but also a means of recycling peanut shells.     

Energy potential and thermogravimetric study of pyrolysis kinetics of biomass wastes

The use of agricultural wastes for energy conversion has been widely studied as renewable and carbon neutral energy sources. This paper aims to evaluate the energetic potential of six agricultural wastes—sugarcane bagasse, bean pods, corn stover, pineapple crown leaves, white cotton and natural coloured cotton stalks, through their characterization and pyrolysis kinetic study. The energetic potential of biomasses was evaluated by ultimate and proximate analysis, higher heating value (HHV), apparent density, and kinetic parameters of conversion and apparent activation energy (E_a) determined by Model-Free kinetics though thermogravimetric analysis data. The results indicate energetic density for dry basis biomasses, such as moisture content less than 7%, volatiles higher than 77% and moderate ash content. The HHVs were higher for the biomass with low O:C ratio. The E_a values increased with increasing O:C ratio and were also influenced by the biomass ash content. Among the studied biomasses, PCL are less explored for energy application, although the results confirm its potential for application in thermochemical processes such as pyrolysis or combustion.

     

生物油TG-FTIR分析与热解气化特性研究

以稻壳快速热解产物生物油为对象,在对其进行热重红外检测的基础上,结合生物油及其轻质、重质组分的热解气化实验,研究了生物油热解气化过程及气体产出特性。结果表明,生物油的热解气化分为两个阶段,一是轻质组分的快速挥发热解;二是重质组分的裂解气化与缩合缩聚,活化能分别为35~38 kJ/mol和15~22 kJ/mol。温度升高,热解气化效率增加,以H₂和CO为主的合成气产量增多,但气体产物热值降低。气体中H₂主要来自轻质组分的热解气化,而重质组分则裂解产生较多的CO、CH₄等物质。     

Scale-up of microwave heating process for the production of bio-oil from sewage sludge

A pilot-scale microwave heating apparatus was constructed for the production of bio-oil from sewage sludge, and the effects of important microwave processing parameters and chemical additives on the quality and yield of bio-oils were investigated. It was found that bio-oil was mainly formed at the pyrolysis temperature range of 200–400 °C. A higher heating rate (faster pyrolysis) not only increased the yield of bio-oil, but also improved the quality of bio-oil according to the elemental composition and calorific values. The maximum bio-oil yield was 30.4% of organic fraction, obtained from the pyrolysis of original sewage sludge at microwave radiation power of 8.8 kW and final pyrolysis temperature of 500 °C. All of five simple additives (KOH, H₂SO₄, H₃BO₃, ZnCl₂, and FeSO₄) reduced the bio-oil yield, but the composition and property of bio-oil varied with the additive types greatly. KOH, H₂SO₄, H₃BO₃ and FeSO₄ were found to improve the quality of bio-oils remarkably according to the calorific value, density, viscosity and carbon content of bio-oils, but ZnCl₂ treatment went against that. GC–MS analysis of the bio-oils showed that, alkali treatment promoted the formation of alkanes and monoaromatics, while acid treatment favored the formation of heterocyclics, ketones, alcohols and nitriles. Compared with sulfate slat FeSO₄, chloride salt ZnCl₂ was a better catalyst for selective catalytic pyrolysis of sewage sludge. The addition of ZnCl₂ only promoted the formation reactions of a few kinds of nitriles and ketones remarkably. It is technologically feasible to produce bio-oil form microwave-induced pyrolysis of sewage sludge by optimizing pyrolysis conditions and selecting appropriate additives.     

Physico-chemical and anatomical characterization of residual lignocellulosic fibers

Anatomical and physico-chemical properties of residual natural fibers (sugarcane bagasse, coconut fibers and peanut hulls) were characterized in order to evaluate their potential for use in the production of particleboard. The bulk density was determined by helium pycnometer and the chemical characteristics by using an electronic pH meter (for pH determination) on fibers dissolved in acidic and neutral detergents (to determine the levels of cellulose, hemicellulose and lignin). The anatomical characteristics were established using scanning electron microscopy coupled with an X-ray detector system, as well as energy dispersive X-ray spectroscopy. Results indicated similarities and differences between physico-chemical and anatomical characteristics of the residual lignocellulosic fibers when compared with the Pinus sp. wood commercially employed in particleboard production. Bulk density and pH for residual lignocellulosic fibers and Pinus sp. wood presented analogous values. Similar amounts of cellulose and lignin were identified between waste fibers and Pinus sp. wood. The presence of silica was identified in coconut fiber, peanut hull and sugarcane bagasse waste fibers, and may affect the mechanical characteristics of panels. Coconut and sugarcane bagasse fibers show surface pores with diameters ranging from 1.2 to 2.1 μm, below the 5 μm identified for Pinus sp. wood. Both fibers present pores distributed over their entire surface, whereas peanut hull fibers have no pores on their surface. This characteristic contributes to resin dispersion among particles, reflecting positively on the physical–mechanical properties of the panels. Particleboards produced with residual lignocellulosic fibers present similar physical–mechanical properties to those of Pinus sp. wood panels.     

Thermal self-sustainability of biochar production by pyrolysis

The pyrolysis of several agricultural and biofuel production residues (grape residues, sugarcane residues, dried distiller's grain, palm oil residues, apple pomace and forestry residue) has been carried out in a pilot bubbling fluidized bed pyrolyzer operating under a range of temperature from 300 to 600 °C and two vapor residence times (2 and 5 s), with the aim of determining their pyrolysis behavior including products yields and heat balance. The composition of the product gases was determined, from which their heating value was calculated. The liquid bio-oil was recovered with cyclonic condensers. The thermal sustainability of the pyrolysis process was estimated by considering the energy contribution of the product gases and of the liquid bio-oil in relation to the pyrolysis heat requirements. The most promising biomass feedstocks for the sustainable production of biochar were indentified. Furthermore, this study presented the char yield in relation to the excess heat that could be obtained by combusting the gas and bio-oil coproducts of biochar production, as functions of pyrolysis temperature and vapor residence time.     

Bio-oil from Jackfruit Peel Waste

Fossil fuels such as petroleum, charcoal, and natural gas sources are the main energy sources at present, but considering their natural limitation in availability and the fact that they are not renewable, there exists a growing need of developing bio-fuel production. Biomass has received considerable attention as a sustainable feedstock that can replace diminishing fossil fuels for the production of energy, especially for the transportation sector. JackfruitwasteisabundantinIndonesiamake itpotentiallyas one of thegreenrefineryfeedstockforthe manufacture ofbio-fuel.As intermediate of bio-fuel,jackfruitpeelsisprocessed intobio-oil. Pyrolysis, a thermochemical conversion process under oxygen-absent condition is an attractive way to convert biomass into bio- oil.In this study, the pyrolysis experiments were carried out ina fixed-bedreactor at a range of temperature of400-600 °C, heating rate range between 10-50 °C/min, and a range of nitrogen flow between 2-4litre/min. The aims of this work were to explore the effects of pyrolysis conditions and to identify the optimum condition for obtaining the highest bio-oil yield.The effect of nitrogen flow rate and heating rate on the yield of bio-oil were insignificant. The most important parameter in the bio-oil production was the temperature of the pyrolysis process.The yield of bio-oil initially increased with temperature (up to 550 °C) then further increase of temperature resulting in the decreased of bio-oil yield. Results showed that the highest bio-oil yield (52.6%)wasobtainedat 550 °C with nitrogen flow rate of 4L/min and heating rate of 50 °C/min. The thermal degradation of jackfruit peel was also studied using thermogravimetric analysis (TGA). Gas chromatography (GC-MS) was used to identify the organic fraction of bio-oil. The water content in the bio-oil product was determined by volumetric Karl-Fischer titration. The physicochemical properties of bio-oil produced from pyrolysis of jackfruit peels such as gross calorific value, pH, kinematic viscosity, density, sulfur content, ash content, pour point and flash point were determined and compared to ASTM standard of bio-oil (ASTM 7544).     

Research on pyrolysis of PCB waste with TG-FTIR and Py-GC/MS

The purpose of this study is to determine the pyrolysis characteristics and gas product properties of printed circuit board (PCB) waste. For this purpose, a combination of Thermogravimetry-Fourier Transform Infrared Spectrum (TG-FTIR) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) techniques is employed. In the TG-FTIR experiment, a heating rate of 10?°C min^?1 and a terminal pyrolysis temperature of 600?°C are applied. The thermal decomposition temperature, weight losses, and the temperature trend of evolving gaseous products of PCB waste are investigated. Py-GC/MS is used for the qualitative and semi-quantitative analysis of the higher-molecular-weight volatile decomposition products. Associated with the analysis results of TG-FTIR and Py-GC/MS for the volatile products, PCB waste degradation could be subdivided into three stages. The main products in the first stage (<293?°C) are H₂O, CH₄, HBr, CO₂ and CH₃COCH₃. High-molecular-weight organic species, including bromophenols, bisphenol A, p-isopropenyl phenol, phenol, etc., mainly evolve in the second stage. In the last stage, at temperature above 400?°C, carbonization and char formation occur. This fundamental study provides a basic insight of PCB waste pyrolysis.     

蔗渣的热解与燃烧动力学特性研究

利用热重分析仪对蔗渣在不同升温速率下的热解、燃烧失重特性进行了研究。采用Friedman法对反应过程中可能存在的反应机理进行初步判断，蔗渣热解过程由其主要组分半纤维素、纤维素和木质素热解的三个独立的平行反应来描述，相应的反应活化能分别为203.92 kJ·mol-1、238.50 kJ·mol-1和77.11 kJ·mol-1； 蔗渣燃烧过程分为两段，第一段类似于其热解过程，第二段由木质素热解和残焦燃烧共同组成的连续反应，反应活化能为255.57 kJ·mol-1和159.11 kJ·mol-1。通过非线性回归法拟合获得的曲线与实验曲线基本一致，证实了蔗渣的热解、燃烧过程中存在着上述假定的反应机理。     

Product distribution from fast pyrolysis of glucose-based carbohydrates

Carbohydrates are the major constituents of biomass. With the growing interest in utilizing bio-oil obtained from fast pyrolysis of biomass for fuels and chemicals, understanding the carbohydrate pyrolysis behavior has gained particular importance. The chemical composition of the bio-oil is an important consideration for its upstream and/or downstream processing. Though the classification of pyrolysis products into overall tar, char and gaseous fraction has evolved as a standard; detailed knowledge of the chemical constituents that determine the quality of bio-oil has received little attention. Furthermore, the speciation arising from primary and secondary reactions has been rarely distinguished. In this study the product distribution arising from the primary reactions during 500 °C fast pyrolysis of several mono-, di- and polysaccharides is studied with the help of micro-pyrolyzer. The study suggests that levoglucosan and the low molecular weight compounds are formed through competitive pyrolysis reactions rather than sequential pyrolysis reactions. It is also shown that the orientation or the position of glycosidic linkages does not significantly influence the product distribution except with 1,6-linked polysaccharide, which showed considerably less formation of levoglucosan than other polysaccharides.     

Fast pyrolysis of rice straw,sugarcane bagasse and coconut shell in an induction-heating reactor

With the application of induction heating, a fast pyrolysis was used for producing valuable products from rice straw, sugarcane bagasse and coconut shell in an externally heated fixed-bed reactor. The effect of process parameters such as pyrolysis temperature, heating rate and holding time on the yields of pyrolysis products and their chemical compositions were investigated. The maximum yield of ca. 50% on the pyrolysis liquid product could be obtained at the proper process conditions. The chemical characterization by elemental (CHNO), calorific, Fourier transform infrared (FT-IR) spectroscopy and gas chromatography/mass spectrometry (GC–MS) showed that the pyrolysis liquid products contain large amounts of water (>65 wt.%), and fewer contents of oxygenated hydrocarbons composing of carbonyl groups, resulting in low pH and low heating values. The results were very similar to bio-oils obtained from other biomass materials. The residual solid (char or charcoal) was also characterized in the present study.     

Characterization of sugarcane and coconut fibers by thermal analysis and FTIR

Pyrolysis of sugarcane bagasse and coconut fiber was studied by thermal analysis in order to characterize their thermal behavior and to identify their constituents by the aid of their thermogravimetric curves and to determine their heat capacity by means of DSC. The Fourier Transform Infrared Spectrum (FTIR) was used to determine the main constituents present in both residues. The thermal degradation of sugarcane bagasse and coconut fiber presents two mass loss steps attributed to the release of humidity and to the decomposition of organic material (hemicellulose, cellulose and lignin). It was expected that the results of DSC analysis were almost the same for both types of biomasses.     

Microwave-assisted pyrolysis of oil palm shell biomass using an overhead stirrer

Oil palm shell biomass contains a high amount of lignin and thus has the potential to be converted into value-added products. If this biomass is not utilised efficiently, significant loss of valuable chemical products may occur, which otherwise can be recovered. In this paper, a new technique using an overhead stirrer to pyrolyse biomass under microwave (MW) irradiation was investigated. The ratio of biomass to activated carbon was varied to investigate its effect on the temperature profile, product yield and phenol content of the bio-oil. Interestingly, the microwave pyrolysis temperature could be controlled by varying the biomass to carbon ratio. The highest bio-oil yield and phenol content in bio-oil were obtained at a biomass to carbon ratio of 1:0.5. Chemical analyses of bio-oil were performed using FT-IR, GC–MS and ¹H NMR techniques. These results indicate that bio-oil consists mainly of aliphatic and aromatic compounds with high amounts of phenol in the bio-oil. Thus, MW pyrolysis with a stirrer successfully produced high-phenol bio-oil compared to other methods. This significant increase in bio-oil quality could either partially or wholly replace petroleum-derived phenol in many phenol-based applications.     

TG-pyrolysis and FTIR analysis of chocolate and biomass waste

Four waste streams from a chocolate factory were examined in view of their possible usage as a fuel: cocoa shell, jute bags, and two qualities of chocolate waste (milk, white). Thus, proximate and ultimate analyses and thermogravimetric analyses coupled with Fourier transform infrared (TG-FTIR) analyses were conducted. It was observed that milk and white chocolates have similar thermal properties; chocolate has a high calorific value (24.5 MJ kg^?1). Pyrolysis of chocolate proceeds in two stages: the first from 190 to 300 °C and the second from 300 to 518 °C. During the first stage, alkaloids, such as theobromine and caffeine, evolve, and sugar decomposes, releasing acids, CO₂, and water. During the second pyrolysis stage, cocoa butter and proteins decompose releasing volatile organics such as esters, acids, amides, phenols, CH₄, CO, etc. Polyphenols such as catechin, procyanidins, etc. decompose during both pyrolysis stages. Generally, chocolate waste yields less CO₂ and CO than cocoa shell and jute. In principle, it appears to be a promising source of energy and could be utilized by both co-firing and pyrolysis, producing fuels or chemicals.     

Evaluation of the Sorptive Capacity of Sugarcane Bagasse and Its Coal for Heavy Metals in Solution

Recycling of sugarcane bagasse and its coal as metal sorbents to capture metal ions from wastewater is the aim of this study. Thus, stability of sugarcane bagasse and its coal, in addition to the solubilities of metal ions in synthetic solution, were determined in this study at different pH values. Also, sorption of Fe, Mn, Cd, and Pb ions with different concentrations (10‐100 mg L^?1) on different grain size fractions of sugarcane bagasse (< 150 > μm) and its coal (< 80 > μm) was carried out under different pH values (2, 4 and 6), dosage (2, 6, and 10 g L^?1), time intervals (15‐300 min.) and temperature (20‐50 °C). The results indicated that the sugarcane bagasse and its coal were more stable at pH 6, and the solubilities of metal ions in the synthetic solution exhibited high values at pH 2 more than pH 4 and 6, respectively. Generally, removal of metal ions using the sorbents increased with the decreasing of grain size fractions and with increasing of pH values (6 > 4 > 2), sorbent doses (10 > 6 > 2 g L^?1) and initial concentrations of metal ions (10‐100 mg L^?1). Coal of sugarcane bagasse was more effective than the sugarcane bagasse for removal of the metal ions from solution. Positive values of ΔH° suggest the endothermic nature of sorption in all cases. The negative Gibb's free energy values indicate the feasibility of the process and spontaneous nature of sorption (Fe‐bagasse coal system), while the positive value of ΔG° suggests the non‐spontaneous character of adsorption of all metals. The negative values of entropy change ΔS° (Pb‐bagasse system) indicate the highly ordered adsorption process in this case, while the positive values of ΔS° show the increased randomness at solid/solution interface during the sorption metal ion on bagasse. The results of activation energy values indicate the order of sorption feasibility is: Pb > Fe > Cd > Mn in the case of bagasse and Fe > Pb > Cd > Mn in the case of coal. Generally, the results of this study suggest that the sugarcane bagasse and its coal might provide an economical method for the removal of metal ions from wastewater.     

Study of products yield of bagasse and sawdust via slow pyrolysis and iron-catalyze

In this paper, the via slow pyrolysis behavior of the bagasse and sawdust were studied at the different heating rates, the different iron-containing blend pyrolysis and the treatment temperature, the further understood for the pyrolysis of agricultural residues. The distribution of the products yield of the slow pyrolysis process, it is typically performed at temperature between 200 and 600 °C, the pyrolysis temperature increased, the bio-liquids and gas yields tended to increase, which at 400 °C was able to achieve maximum bio-liquids yields, the biochar yields tended to downward. For different heating rate, in the heating rate ranges for 80–100 W, the bio-liquids products yield curve increased from 44.5 wt% to 46.5 wt% for bagasse; the sawdust products yield increased from 41 wt% to 42.75 wt%. Iron-catalysts blend pyrolysis (0, 10, 25, 40 and 50 wt%), the bagasse bio-liquid yields respectively 56.25 wt% in the presence 50% iron-catalysts blend pyrolysis; the sawdust bio-liquid yields respectively 52.5 wt% in the presence 40% iron-catalysts blend. The pyrolysis process were calculated according to the kinetic mechanism were examined, the pyrolysis activation energy was between 6.55 and 7.49 kcal/mol for bagasse. Sawdust the pyrolysis activation energy was between 11.52 and 11.76 kcal/mol. Therefore, in this study a pyrolysis model of bagasse and sawdust thermal treatment may provide both agricultural and forestry transformation importance of resources.     

纤维素快速热裂解机理试验研究 Ⅰ. 试验研究

在热辐射反应器上对纤维素快速热裂解过程中主要一次产物的生成规律进行了研究。结合焦油的GC-MS分析，发现左旋葡聚糖（LG）作为最重要的液体产物，占据了焦油质量的45w%～85w%。LG的生成主要集中在550 ℃～650 ℃中温辐射源区域，其产量随温度的变化存在一最佳值，约在640 ℃左右得到54.4w%的最高产率。乙醇醛(HAA)作为焦油的第二重要组分，在焦油中达到了6w%～14w%的比例，与之含量接近的还有1-羟基-2-丙酮(Acetol)，约为3.5w%～8w%。它们的产率在相当大的范围内随温度的升高而增加，表明高温有利于它们的生成。同时分析表明乙醇醛、1-羟基-2-丙酮是在与LG的竞争过程中作为纤维素热裂解一次产物直接生成的。