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1.
Characteristic Studies on the Pyrolysis Products from Hydrolyzed Canadian Lignocellulosic Feedstocks
Lignocellulosic feedstocks are utilized for the production of fuel ethanol and butanol through dilute acid/enzymatic hydrolysis and fermentation. Hydrolysis residue, a major by-product of biomass hydrolysis, is rich in recalcitrant carbon as majority of cellulosic and hemicellulosic components are released during pretreatment. With the intention of their effective utilization, hydrolysis residues from forestry (pinewood), energy crop system (timothy grass), and agriculture (wheat straw) were pyrolysed in a fixed-bed reactor at 600 °C with slow heating rate of 5 °C/min for 4 h. In order to understand the product (biochar, bio-oil, and gases) properties and advocate their energy and environmental values, chemical characterizations such as carbon–hydrogen–nitrogen–sulfur analysis, inductively coupled plasma-mass spectrometry, pH, electrical conductivity, scanning electron microscopy, porosity analysis, thermogravimetric analysis, X-ray diffraction, Fourier transform infrared (FTIR) and Raman spectroscopy, nuclear magnetic resonance (NMR) and gas chromatography–mass spectrometry (GC-MS) were employed. The yield of biochar, bio-oil and gases was 38.9–41.7, 18.6–22.3, and 24.9–28.8 wt%, respectively. The high pH and electrical conductivity of biochars with substantial amounts of Na, Mg, K, and Ca indicated their alkaline and saline nature, which would necessitate proper agronomical soil applications. Variable intensities of C–C, C–H, C–O, O–H, and C–N functional groups were detected in the FTIR spectra of residues, biochars, and bio-oils. Raman spectroscopy showed the development of graphite (1,580–1,610 cm?1) and defect (1,325–1,380 cm?1) carbon structures in biochars. 1H NMR of bio-oils indicated aromatics, olefinics, and aliphatics, whereas 13C NMR indicated carbonyls, aromatics, carbohydrates, alkyls, methoxy, and hydroxy carbon. GC studies of pyrolysis gases identified chiefly H2 and CO with traces of CH4, CO2, and C2+ components. 相似文献
2.
The biochar is an important carbon-rich product that is generated from biomass sources through pyrolysis. Biochar (charcoal) can be both used directly as a potential source of solid biofuels and as soil amendments for barren lands. The aim of this study was investigate influence of pyrolysis temperature on the physicochemical properties and structure of biochar. The biochars were produced by pyrolysis of rapeseed (Brassica napus L.) using a fixed-bed reactor at different pyrolysis temperatures (400–700°C). The produced biochars were characterized by proximate and elemental analysis, Brunauer–Emmett–Teller (BET) surface area, particle size distributions, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy. The results showed that both chemical and surface properties of the biochars were significantly affected by the pyrolysis temperature. Aromatic hydrocarbons, hydroxyl and carbonyl compounds were the majority components of the biochar. The biochar obtained at 700°C had a high fixed carbon content (66.16%) as well as a high heating value, and therefore it could be used as solid fuel, precursor in the activated carbons manufacture (specific surface area until 25.38 m2 g?1), or to obtain category-A briquettes. 相似文献
3.
Predicting phosphorus bioavailability from high-ash biochars 总被引:4,自引:0,他引:4
Background and aims
Biochars are highly variable in nutrient composition and availability, which are determined by types of feedstock and pyrolysis conditions. The aim of this research was to (a) study the bioavailability of phosphorus (P) in biochars using different feedstocks and pyrolysis conditions; (b) develop a robust chemical method for biochar P availability measurements.Methods
In the present study, (a) chemical analysis – including total P and extractable P (2% citric acid, 2% formic acid, and neutral ammonium citrate extraction), and (b) a bioassay test using rye-grass grown in a P deficient sandy soil were used to compare the P bioavailability of different biochars. Biochars were produced from two different feedstocks (dairy manure-wood mixture, MAe; biosolid-wood mixture, BSe) at four different pyrolysis temperatures (250, 350, 450, and 550°C).Results
Results showed that P in feedstock was fully recovered in the biochars. After 6 harvests, the biochars were as effective as the P fertilizers tested [Sechura phosphate rocks (SPR) and calcium dihydrogen phosphate (CaP)] in increasing the shoot yield. However, P uptake followed the order of CaP >MAe biochars >BSe biochars >SPR, on a same TP basis. Based on the Mitscherlich equation, 2% formic acid was the most sensitive indicator of P bioavailability in biochars.Conclusions
The results suggest that high-ash biochars with high P concentrations are potential P sources with high-agronomic efficiency. We propose the use of 2% formic acid extraction to predict the availability of P in ash-rich biochars. 相似文献4.
Zygomycetes such as Cunninghamella elegans seem to be promising biosorbents for pollutants removal from wastewaters because of their particular cell wall characteristics.
In this article the effect of ten culture media on C. elegans biomass composition was investigated by means of Fourier transform infra red spectroscopy (FTIR). Biomasses grown on starches
from potatoes and cereals were characterised by high amount of chitin and polysaccharides, the glucose gave rise to a biomass
rich in acidic polysaccharides and lipids. By contrast, biomasses grown on corn steep liquor were poor in acidic polysaccharides
and, when N sources and micronutrients were added, rich in proteins. The lipid content of the biomass generally increased
by halving nutrients. Biosorption yields of these biomasses towards four wastewater models were assessed in terms of colour,
salts and toxicity reduction. The biomasses rich in proteins and acid polysaccharides were less effective in removing reactive
and direct dyes, whereas those rich in cationic polysaccharides showed a higher affinity for these dyes. Both chromatography
and FTIR analyses showed that biomasses cultured in halved C and N had the highest affinity for salts. The wastewaters detoxification
was quite always achieved, with values often lower that the Italian legal threshold limit. 相似文献
5.
With the application of induction-heating, the pyrolytic experiments have been carried out for three sewage sludges from the food processing factories in an externally heated fixed-bed reactor. The thermochemical characteristics of sludge samples were first analyzed. The results indicated that the calorific value had about 15 MJ/kg on an average, suggesting that it had a potential for biomass energy source. However, its nitrogen concentration was relatively high. From the thermogravimetric analysis (TGA) curves, it showed that the pyrolysis reaction can be almost finished in the temperature range of 450-750 degrees C. The yields of resulting liquid and char products from the pyrolysis of sewage sludge were discussed for examining the effects of pyrolysis temperature (500-800 degrees C), heating rate (200-500 degrees C/min), and holding time (1-8 min). Overall, the variation of yield was not so significant in the experimental conditions for three sewage sludges. All results of the resulting liquid products analyzed by elemental analyzer, pH meter, Karl-Fischer moisture titrator and bomb calorimeter were in consistence with those analyses by FTIR spectroscopy. Furthermore, the pyrolysis liquid products contained large amounts of water (>73% by weight) mostly derived from the bound water in the biosludge feedstocks and the condensation reactions during the pyrolysis reaction, and fewer contents of oxygenated hydrocarbons composing of carbonyl and nitrogen-containing groups, resulting in low pH and low calorific values. 相似文献
6.
The residues from the palm oil industry are the main contributors to biomass waste in Malaysia, and these wastes require extra attention with respect to handling. The biomass waste is a renewable resource that can potentially be used to produce absorbents, fuels, and chemical feedstocks through the pyrolysis process. In this study, the wastes of palm shell, empty fruit bunches, and mesocarp fiber were characterized and then pyrolyzed in a fixed-bed reactor under the following conditions: a temperature of 500 °C, a nitrogen flow rate of 2 L/min and reaction time of 60 min. After pyrolysis, characterization of the products with an emphasis on the bio-oil and the bio-char was performed using various approaches (including Karl Fischer water-content tests, FTIR, SEM, TGA and CNH/O analyses). The results showed that the pyrolysis of palm oil wastes yielded more bio-oil than bio-char or non-condensable gases. The results also indicated that all of the bio-oils were acidic and contained high levels of oxygen. The bio-oils heating values were low and varied from 10.49 MJ/kg to 14.78 MJ/kg. The heating values of the bio-chars (20–30 MJ/kg) were higher than those of the bio-oils. Among the biomasses studied in this work, palm shell contained the highest level of lignin and showed the highest levels of bio-char yield and fixed and elemental carbon in the raw and bio-char form. 相似文献
7.
Characterization of 60 types of Chinese biomass waste and resultant biochars in terms of their candidacy for soil application
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Xiaoyin Sun Ruifeng Shan Xuhui Li Jihua Pan Xing Liu Ruonan Deng Junyao Song 《Global Change Biology Bioenergy》2017,9(9):1423-1435
The composition and pyrolysis characteristics of 60 types of biomass waste from the following six source categories were compared: agricultural residues, woody pruning waste from gardens and lawns, aquatic plant material from eutrophic water bodies, nutshells and fruit peels, livestock manure and residual sludge from municipal wastewater treatment. The yield and physicochemical characteristics of the biochar produced from these feedstocks at 350 °C, 500 °C and 650 °C were also examined. Results of correlation and canonical correspondence analysis between feedstock composition and biochar properties showed that feedstock type played an important role in controlling yield and properties of biochars. The yields of biochar dry ash‐free (daf.) basis were positively correlated with cellulose, lignin and lignin/cellulose content of feedstock; and ash content hampered the biochar production. Furthermore, the intensity of correlation between biochar yield and its feedstock composition was improved with pyrolysis temperature and degree of feedstock decomposition. The fixed carbon content in biochar was also negatively influenced by ash content of feedstock, and it increased with increasing pyrolysis temperature when the ash content was below 34.57% in feedstock and decreased when the ash content exceeded. The fixed carbon production in biochar per unit ash‐free mass (af.) was positively related to cellulose, lignin and lignin/cellulose content in feedstock, which were same with the yield of biochar (daf.). But on the contrary, the volatiles content in biochar (af.) had negative correlation with these organic constituents. For most feedstocks, the differences in the biochar characteristics among the biomass categories were greater than within any individual category. C/N, H/C and O/C atomic ratio and bulk density of biochar from different types of biomass were also compared. The results will provide guidance for the reutilization of biomass wastes and production of biochar with specified properties for soil amendment applications. 相似文献
8.
Fast pyrolysis of lignocellulosic biomass is a facile method for producing high yields of liquid fuel intermediates. However, because most fast pyrolysis oils are highly oxygenated, acidic, and unstable, identification of feedstocks that produce higher quality pyrolysis liquids is desirable. Therefore, the effect of feedstock protein content was studied by performing fast pyrolysis experiments on biomass with varying protein content. The feedstocks ranged from low-protein content, ??5% up to feedstocks with >40 wt.% protein content. Protein content was not a major factor in the yield of pyrolysis oil or the distribution of biomass carbon into the pyrolysis products. However, elevated levels of protein did cause a deoxygenation effect in the pyrolysis process with more of the oxygen rejected from the biomass as water. The deoxygenation caused the pyrolysis oil from the higher protein containing biomass to have higher energy content. Furthermore, the concentration of basic nitrogen groups caused the pyrolysis oil from the higher protein biomass to shift to a more neutral pH and lower total acid number than has been measured typically for lignocelluloic biomass pyrolysis oils. Some of the pyrolysis oils, particularly those from the mustard seed family presscakes exhibited better thermal stability than low-protein pyrolysis oils. 相似文献
9.
Poplars and their hybrids are widely planted in both plantation forestry and agroforestry systems of the world. Along with the utilization and plantation management processes, a large amount of biomass residues are produced, but the relationship between biochar properties and soil CO2 emissions is largely unknown. Here, a laboratory incubation study was conducted to assess the effects of different biochars and their corresponding biomass residues on soil CO2 emissions during the 180 days of incubation. Poplar residue-derived biochars were larger in the surface area and total pore volume but lower in nutrients and pH values than the rice straw-derived biochar. Increasing pyrolysis temperature led to a decrease in the total nitrogen (TN) content of poplar leaf- and rice straw-derived biochars, but enhanced the TN in the poplar twig- and poplar bark-derived biochars. After 180-day incubation, the total cumulative CO2 emission decreased by 33.1%–73.8% in the biochar amendments compared to their corresponding biomass residue addition, whereas the biochars derived from poplar twig and bark residues had more positive effects on reducing soil CO2 emissions, but depended on the pyrolysis temperature. Correlation analysis showed a significant and positive correlation between the CO2 emissions and TN content of bio-based materials but the negative relationships to total carbon content and C/N ratio. Meanwhile the positive correlations of CO2 emissions to the surface area, t-plot micropore area, and volume of the biochars were detected. Our results suggest that application of poplar twig- and poplar bark-derived biochars has a great potential for mitigating global warming. 相似文献
10.
Agustín García Barneto José Ariza Carmona José E. Martín Alfonso Luís Jiménez Alcaide 《Bioresource technology》2009,100(17):3963-3973
Non-isothermal thermogravimetric analysis (TGA) data of biomasses and pulps originating from non-wood and alternatives materials (i.e., Tagasaste or rice straw) have been fitted with refined models, which include autocatalytic kinetics. Data sets were obtained for different experimental conditions, such as variations of heating rate and atmosphere, i.e., inert (pyrolysis) versus oxidative atmosphere (combustion). Besides the access to classical kinetic parameters (pre-exponential factor, activation energy, and reaction order), the improved data analysis enabled the determination of the chemical composition of the samples (cellulose, hemicellulose, extractives, lignin). The latter compared very well with those obtained by conventional methods (chemical analysis, HPLC). Given the reduced environmental impact and rapidness of the method, potential applications for research related to new biomasses and industrial processes can be foreseen. 相似文献
11.
Biomass as an energy source: thermodynamic constraints on the performance of the conversion process 总被引:4,自引:0,他引:4
In the present work an equilibrium model (gas-solid), based on the minimization of the Gibbs energy, has been used in order to estimate the theoretical yield and the equilibrium composition of the reaction products (syngas and char) of biomass thermochemical conversion processes (pyrolysis and gasification). The data obtained from this model have also been used to calculate the heating value of the fuel gas, in order to evaluate the overall energy efficiency of the thermal conversion stage. The proposed model has been applied both to partial oxidation and steam gasification processes with varying air to biomass (ER) and steam to carbon (SC) ratio values and using different feedstocks; the obtained results have been compared with experimental data and with other model predictions obtaining a satisfactory agreement. 相似文献
12.
Mackenzie J. Denyes Michèle A. Parisien Allison Rutter Barbara A. Zeeb 《Journal of visualized experiments : JoVE》2014,(93)
The physical and chemical properties of biochar vary based on feedstock sources and production conditions, making it possible to engineer biochars with specific functions (e.g. carbon sequestration, soil quality improvements, or contaminant sorption). In 2013, the International Biochar Initiative (IBI) made publically available their Standardized Product Definition and Product Testing Guidelines (Version 1.1) which set standards for physical and chemical characteristics for biochar. Six biochars made from three different feedstocks and at two temperatures were analyzed for characteristics related to their use as a soil amendment. The protocol describes analyses of the feedstocks and biochars and includes: cation exchange capacity (CEC), specific surface area (SSA), organic carbon (OC) and moisture percentage, pH, particle size distribution, and proximate and ultimate analysis. Also described in the protocol are the analyses of the feedstocks and biochars for contaminants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), metals and mercury as well as nutrients (phosphorous, nitrite and nitrate and ammonium as nitrogen). The protocol also includes the biological testing procedures, earthworm avoidance and germination assays. Based on the quality assurance / quality control (QA/QC) results of blanks, duplicates, standards and reference materials, all methods were determined adequate for use with biochar and feedstock materials. All biochars and feedstocks were well within the criterion set by the IBI and there were little differences among biochars, except in the case of the biochar produced from construction waste materials. This biochar (referred to as Old biochar) was determined to have elevated levels of arsenic, chromium, copper, and lead, and failed the earthworm avoidance and germination assays. Based on these results, Old biochar would not be appropriate for use as a soil amendment for carbon sequestration, substrate quality improvements or remediation. 相似文献
13.
Ben Guerrero Emiliano Joel Arneodo Raquel Bombarda Campanha Patrícia Abr?o de Oliveira M?nica T. Veneziano Labate Thaís Regiani Cataldi Eleonora Campos Angel Cataldi Carlos A. Labate Clenilson Martins Rodrigues Paola Talia 《PloS one》2015,10(8)
Saccharum officinarum bagasse (common name: sugarcane bagasse) and Pennisetum purpureum (also known as Napier grass) are among the most promising feedstocks for bioethanol production in Argentina and Brazil. In this study, both biomasses were assessed before and after acid pretreatment and following hydrolysis with Nasutitermes aquilinus and Cortaritermes fulviceps termite gut digestome. The chemical composition analysis of the biomasses after diluted acid pretreatment showed that the hemicellulose fraction was partially removed. The (hemi) cellulolytic activities were evaluated in bacterial culture supernatants of termite gut homogenates grown in treated and untreated biomasses. In all cases, we detected significantly higher endoglucanase and xylanase activities using pretreated biomasses compared to untreated biomasses, carboxymethylcellulose and xylan. Several protein bands with (hemi) cellulolytic activity were detected in zymograms and two-dimensional gel electrophoresis. Some proteins of these bands or spots were identified as xylanolytic peptides by mass spectrometry. Finally, the diversity of cultured cellulolytic bacterial endosymbionts associated to both Argentinean native termite species was analyzed. This study describes, for the first time, bacterial endosymbionts and endogenous (hemi) cellulases of two Argentinean native termites as well as their potential application in degradation of lignocellulosic biomass for bioethanol production. 相似文献
14.
Effects of biochar from slow pyrolysis of papermill waste on agronomic performance and soil fertility 总被引:112,自引:0,他引:112
L. Van Zwieten S. Kimber S. Morris K. Y. Chan A. Downie J. Rust S. Joseph A. Cowie 《Plant and Soil》2010,327(1-2):235-246
The amendment of two agricultural soils with two biochars derived from the slow pyrolysis of papermill waste was assessed in a glasshouse study. Characterisation of both biochars revealed high surface area (115 m2 g?1) and zones of calcium mineral agglomeration. The biochars differed slightly in their liming values (33% and 29%), and carbon content (50% and 52%). Molar H/C ratios of 0.3 in the biochars suggested aromatic stability. At application rates of 10 t ha?1 in a ferrosol both biochars significantly increased pH, CEC, exchangeable Ca and total C, while in a calcarosol both biochars increased C while biochar 2 also increased exchangeable K. Biochars reduced Al availability (ca. 2 cmol (+) kg?1 to <0.1 cmol (+) kg?1) in the ferrosol. The analysis of biomass production revealed a range of responses, due to both biochar characteristics and soil type. Both biochars significantly increased N uptake in wheat grown in fertiliser amended ferrosol. Concomitant increase in biomass production (250% times that of control) therefore suggested improved fertiliser use efficiency. Likewise, biochar amendment significantly increased biomass in soybean and radish in the ferrosol with fertiliser. The calcarosol amended with fertiliser and biochar however gave varied crop responses: Increased soybean biomass, but reduced wheat and radish biomass. No significant effects of biochar were shown in the absence of fertiliser for wheat and soybean, while radish biomass increased significantly. Earthworms showed preference for biochar-amended ferrosol over control soils with no significant difference recorded for the calcarosol. The results from this work demonstrate that the agronomic benefits of papermill biochars have to be verified for different soil types and crops. 相似文献
15.
不同炭化温度制备的蚕丝被废弃物生物炭对重金属Cd2+的吸附性能 总被引:2,自引:0,他引:2
以蚕丝被废弃物为原料,在300、500和700 ℃高温缺氧条件下热解炭化制备成3种生物炭(BC300、BC500和BC700).利用扫描电镜(SEM)、傅里叶红外光谱仪(FT-IR)、X-射线衍射仪(XRD)、比表面积分析仪等对其理化性质进行表征,并研究了不同温度下制备的生物炭对溶液中Cd2+的吸附特性.结果表明: 随着炭化温度上升,BET比表面积、pH、灰分均增大,生物炭表面形态结构越来越不规则.XRD结果显示:不同温度下获得的生物炭中均含有一定量的方解石,FT-IR光谱图上的峰主要为-OH和方解石典型的吸收峰;pH对生物炭吸附Cd2+的影响不大;Langmuir方程能更好地拟合3种生物炭对Cd2+的吸附等温过程,其最大吸附量分别为25.61、52.41和91.07 mg·g-1.3种生物炭对Cd2+吸附过程均更符合准二级动力学方程,且BC700对Cd2+的吸附效果最佳.进一步研究离子浓度及阳离子共存对BC700吸附Cd2+的影响,结果显示: NaCl浓度越高,对Cd2+的吸附抑制越明显;共存阳离子中,Ca2+和Mg2+对Cd2+的吸附抑制更明显,而K+几乎无影响.因此,以蚕丝被废弃物制备的生物炭作为去除水体中Cd2+的吸附剂具有较强的应用潜力. 相似文献
16.
Compositional and Thermal Evaluation of Lignocellulosic and Poultry Litter Chars via High and Low Temperature Pyrolysis 总被引:2,自引:0,他引:2
Inorganic elements in biomass feedstocks can influence thermochemical reactions as well as the resultant char’s elemental, compositional, and thermal characteristics. Chars were produced using slow pyrolysis under low (≤400°C) and high (≥500°C) temperature regimes from sugarcane bagasse, peanut hulls, pecan shell, pine chips, poultry litter, and switchgrass. The chars and raw feedstocks were characterized for their elemental, structural, and thermal properties to ascertain the implications of feedstock selection and pyrolysis temperatures on these properties. Char mass yields from the six feedstocks ranged between 28% and 78% by weight while carbon yields ranged between 44% and 89%. In both instances, lower yields were obtained with increasing pyrolysis temperature. Higher pyrolysis temperatures (≥500°C) resulted in more neutral to alkaline chars possessing greater ash contents and increased aromatic character with narrow O/C and H/C ratios. A significant exponential curve response (r 2?=?0.87, P?<?0.001) was revealed between char mass yields vs. pyrolysis temperature. All raw feedstocks and chars contained mixed amounts of macro-, micro-, and trace element concentrations. The higher heating values (HHV) tended to increase with heightened pyrolysis temperature with some chars producing >30 MJ kg?1. The chars’ HHV values inversely correlated to their total ash and Cl content. Lignocelluloses chars had better thermal characteristics and lower ash quality concerns implying suitable service in thermal energy production. In contrast, poultry litter char had greater ash contents, medium HHV values, and contained corrosive inorganic elements, which rendered it problematic as a feedstock for thermal energy generation. 相似文献
17.
Sobhy M. Yakout 《Bioremediation Journal》2015,19(2):171-182
Biochar derived from agricultural biomass waste is increasingly recognized as a multifunctional material for various applications according to its characteristics. In this study, rice straw–derived biochars were produced at different temperatures (550, 650, 750°C), then they were modified by using different oxidizing agents, including KOH, HNO3, H2SO4, H2O2, and KMnO4. The influence of carbonization temperature and the oxidizing agent's nature on the surface chemistry was investigated. Fourier transform infrared (FTIR) analysis detected lactone, carbonyl, quinone or conjugated quinone, carboxyl-carbonate structure, and alcohol groups in most of the oxidized samples. Modified biochars have low pH values compared with their parent biochars. This is due to the fact that most treatments of biochar increase the acidic functional groups on the surface. Modified biochars presented greater capacities for adsorption of organic species of different molecular sizes such as iodine, phenol, and methylene blue from solutions. Such behavior proves that the most important surface properties of these biochars affecting their solution adsorption behavior are their acidity/alkalinity and hydrophilicity. 相似文献
18.
Biological pretreatment of wheat straw by Phanerochaete chrysosporium supplemented with inorganic salts 总被引:1,自引:0,他引:1
Inorganic salts and tween 80 are known to induce the lignin degrading peroxidase expression of Phanerochaete chrysosporium in submerged culture. In this study, the wheat straw pretreatment supplemented with inorganic salts (salts group), tween 80 (plus) and no supplementation to the biomass (minus) were examined. Among the solid state fermentation groups, salts group resulted in a substantial degradation of wheat straw within one week, along with the highest lignin loss (25%) and ~250% higher efficiency for the total sugar release through enzymatic hydrolysis. The results were correlated with pyrolysis GC-MS (Py-GC-MS), thermogravimetric (TG)/differential thermogravimetric (DTG) and X-ray diffraction (XRD). The results suggested that the supplementation of inorganic salts in the solid state fermentation of wheat straw significantly enhances the degradation rate of the biomass by P. chrysosporium which can be exploited as an alternative means to existing pretreatment technologies. 相似文献
19.
Neeranuch Phusunti Worasak Phetwarotai Charndanai Tirapanampai Surajit Tekasakul 《Bioenergy Research》2017,10(4):1005-1017
Microalgae are a promising source of protein and biofuels. This study involved the extraction of soluble proteins from raw microalgae using subcritical water hydrolysis followed by pyrolysis of the resulting spent microalgal biomass for bio-oil production. The extraction process produced solubilized protein in amounts up to 10 wt% of the dry biomass. The effects of hydrolysis temperature (150–220 °C), process time (90–180 min), and initial pH (2–12) on the chemical compositions and reactivity of the spent biomass as biofuel intermediates were investigated. It was found that when the temperature and time increased, the protein and carbohydrate fractions of the spent biomass were reduced, while their lipid fraction increased. A low initial pH led to lower protein content in the spent biomass. Compared with the raw microalgae, the spent biomass gave a higher yield of pyrolytic bio-oil that contained much less of the N-containing compounds and higher amounts of long-chain fatty acids (C16) and C14–C20 long-chain hydrocarbons. In addition, enhanced energy recovery and a reduction in the energy consumption of the pyrolysis process were the other benefits acquired from the protein extraction. Therefore, subcritical water hydrolysis was considered to be an effective process to recover solubilized proteins, enhance the properties of the spent biomass, improve the energy balance of the subsequent pyrolysis process, and raise the quality of the bio-oil. 相似文献
20.
The kinetic parameters such as pre-exponential factor and activation energy of hemicellulose, cellulose, and lignin were well determined by the linear regressions of selected, sufficient thermogravimetric data, and close to literature values. The pyrolysis of biomass can be divided into four stages. There was only drying in the zeroth stage (<150°C). In the first stage (150-250°C), some light hydrocarbons were produced with the early pyrolysis of biomass. The biomass was mainly pyrolyzed in the second stage (250-500°C) with higher reaction rates than those of other stages. The productions of H(2) and CO(2) in the third stage (>500°C) may be able to be the evidence of self-gasification of char existing at higher temperatures. 相似文献