FUEL
·
2018
·
IF 4.908
Yi Wei,Jijian Hong,Weirong Ji
Digestate, the residue following of anaerobic digestion , had attracted great attention recently as potential feedstock of pyrolysis . The results of component analysis verified that digestate was suitable for phenol production due to its considerable lignin content. The thermal degradation of lignin in digestate mainly occurred around 350–450 °C in thermogravimetric analysis . The amorphous cellulose in digestate decomposed to short-chain acids, water and syngas rather than furfural at low temperature around 280 °C. Pyrolysis of digestate for phenol production was conducted under different reaction temperature and pressure. High reaction temperature contributed to phenol formation by facilitating the cleavage reactions of β-O-4 and C–C linkages among three phenylpropane units in lignin. Pyrolysis pressure promoted secondary monomolecular dissociation reactions of methoxyphenol to yield phenol and alkyl-phenol. The maximum phenolics (70.4%) and phenol (42.6%) contents were achieved at 450 °C with 5 MPa pressure in this work.
研究领域:
生物能源
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2019
·
IF 6.395
Yi Wei,Jitong Tang,Jiale Xie,Chaoyue Shen
Molten alkali carbonates (MC) pyrolysis technology is proposed to dispose digestate waste and convert it into high value-added phenolics in this work. The results showed that temperature strongly affected phenolic production by promoting the depolymerization of lignin, while particle size had less influence on phenolic productions owing to the catalysis and dynamic diffusion of alkali metal ions. Meanwhile, the effect of mass ratio between sample and molten carbonates was investigated by a series of differentiated proportions from 5 to 25%. The optimum reaction conditions were 10% of mass ratio in a particle size from 0.6 to 0.85 mm at 450 °C, with the maximum phenolics yield of 67.08% in organic. In sum, 5.6 g of phenolics and 0.96 g of guaiacols were generated from 100 g of digestate. Compared with conventional pyrolysis method, the methoxyl group in liquid product could be efficiently removed at atmosphere in molten carbonates. Additionally, thermogravimetric analysis further demonstrated that alkali metal ions (Li + , Na + and K + ) promoted the primary degradation of lignin and secondary monomolecular dissociation reactions of methoxyphenol.
研究领域:
生物化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2016
·
IF 4.219
Guangfei Qu,Weiwei He,Yingying Cai,Xi Huang,Ping Ning
This study discussed the catalytic cracking process of cellulose in ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([bmim]OTF) under 180 °C, 240 °C and 340 °C, found that [bmim]OTF is an effective catalyst which can effectively reduce the pyrolysis temperature(nearly 200 °C) of the cellulose. FRIR, XRD and SEM were used to analyze the structure characterization of fiber before and after the cracking; GC–MS was used for liquid phase products analysis; GC was used to analyze gas phase products. The results showed that the cellulose pyrolysis in [bmim]OTf mainly generated CO 2 , CO and H 2 , also generated 2-furfuryl alcohol, 2,5-dimethyl-1,5-diallyl-3-alcohol, 1,4-butyrolactone, 5-methyl furfural, 4-hydroxy butyric acid, vinyl propionate, 1-acetoxyl group-2-butanone, furan formate tetrahydrofuran methyl ester liquid product, and thus simulated the evolution mechanism of cellulose pyrolysis products based on the basic model of cellulose monomer.
研究领域:
化学工程
·
生物质能
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COMBUSTION AND FLAME
·
2022
·
IF 5.767
Kai-Ru Jin,Zhi-Hao Zheng,Ling-Nan Wu,Qiang Xu,Bing-Zhi Liu,Zhan-Dong Wang,Zhen-Yu Tian
Pyrolysis of norbornadiene (NBD) was investigated in a jet-stirred reactor at 760 torr and within the temperature range of 560 to 1100 K. 37 products and intermediates ranging from m/z = 26 to 178 were identified and quantified by using synchrotron radiation photoionization molecular-beam mass spectrometry accompanied by gas chromatography . The C 7 H 8 isomers, including NBD, cycloheptatriene (CHT) and toluene (A1CH 3 ), were differentiated. Acetylene (C 2 H 2 ), cyclopentadiene (C 5 H 6 ), C 7 H 8 isomers and other aromatics are abundant during the pyrolysis process. A detailed kinetic model was developed with reasonable predictions against the measured results, involving 264 species and 1259 reactions, which is helpful to understand the kinetic and heat features of initial consumption as well as the synergistic effect of C 2 H 2 , C 5 H 6 and A1CH 3 to the formation of aromatics. Rate-of-production analysis shows that the pyrolysis of NBD experiences two stages. The first stage involves the isomerization and decomposition of NBD, yielding A1CH 3 , CHT, C 5 H 6 and C 2 H 2 . Branching ratio analysis shows that C 5 H 6 and C 2 H 2 are dominant products in the first stage. Heat release analysis indicates that the first stage is endothermic. The second stage involves the pyrolysis and interactions of first-stage products to produce light hydrocarbons and polycyclic aromatic hydrocarbons like indene, naphthalene , acenaphthylene, fluorene and phenanthrene. Three routes dominate the formation of indene, including C 5 H 6 + C 5 H 5 , benzyl radical + C 2 H 2 and cycloheptatrienyl radical + C 2 H 2 , the last one of which has been scarcely considered in the previous investigation. Sensitivity analysis indicates the reactions in the first stage exhibit strong promoting effects for the consumption of NBD, while the second-stage reactions play minor roles in NBD consumption. This work would enrich the understanding of NBD consumption, PAH formation and heat release.
研究领域:
化学动力学
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燃料化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2021
·
IF 5.541
Zhen-Guo Fan,Zhen-Yu Tian,Wang Li,Zhi-Hao Zheng,Jiu-Zhong Yang
N, N-dimethylformamide (DMF) is a kind of general solvent in Li-ion industry and nitrogen-containing component of amines fuels. The trace vapor of DMF is very harmful to human and environment, which could be treated by pyrolysis. The pyrolysis of DMF was newly carried out in a flow reactor at 30 Torr within 873–1273 K. Synchrotron radiation single photoionization coupled with molecular beam mass spectrometry was employed to detect the reactants, intermediates and products. 26 species were identified and quantified. Products related to NOx, such as nitrosomethane, nitrosyl cyanide and N-methylformamide were identified. With the temperature increasing, the mole fractions of species tend to increase monotonically, while nitrosyl cyanide, ethyl radical, cyclopropane , carbon monoxide , ethanol, acetaldehyde and ethanol exhibit peak-shaped curves. Hydrogen abstractions and dissociations are the main initial pathways of DMF consumption. As the main hydrocarbon products, methane and ethylene are predominantly formed by the H abstraction reaction by methyl radical and the β-scission of ethyl radical, respectively. Carbon monoxide is mainly generated from the dissociation of DMF and its mole fraction is at the same level as the fuel DMF. HCN is the most abundant product among all the carbonitride species via H abstraction of CH 2 =NH as well as the collisions of CN with alkanes and aldehydes. These results provide a theoretical basis for further study of treating DMF in the exhaust fumes through pyrolysis and have reference value for the clean utilization of amine fuels.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 48
·105247-105258
·
IF 5.8
Chen Yuzhen,Tan Yan,Su Lezhu,Zou Wangqi,Wu Binhai,Gao Wenbin,Hu Zhan,Li Aoxuan,Zhou Zhi,Zhou Nan
At present, studies on biochar transport have focused on biochar obtained by oxygen-limited pyrolysis, which may differ from conventional biochar produced by incineration in nature. This work investigated the transport and retention mechanisms of three types of oxygen-limited pyrolytic biochar and three types of traditional biochar in saturated porous media. The results showed that the specific surface area of the three oxygen-limited pyrolysis biochar (180–200 m 2 ·g −1 ) was higher than that of the traditional biochar (50–60 m 2 ·g −1 ). Therefore, the retention capacity of pyrolytic biochar is strong and the permeability is less than 0.1. The absolute value of the zeta potential of traditional biochar is greater than 30 mV, and the electrostatic repulsion generated is stronger, with a peak penetration rate of 0.16. Moreover, the zeta potential of biochar and traditional biochar is regulated by pH value and ionic strength. In acidic conditions or solutions with high ionic strength, the zeta potentials of the six types of biochar changed to about − 15 mV, and the second minimum value was less than 0, indicating that there was a tendency for sedimentation. This study provides a new perspective for assessing the transport and environmental risks of biochar in the environment.
研究领域:
环境科学
·
土壤学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Xiaoran Li,Kehui Cen,Liangcai Wang,Dongxia Jia,Xiefei Zhu,Dengyu Chen
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, C O, 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.
研究领域:
能源与环境科学
·
生物质工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2021
·
IF 5.541
Yongdi He,Jinou Song,Yuan Zhuang,Jiuzhong Yang,Zhongwei Meng,Qiang Xu
An experimental study of 1-nitropropane (1-NP) pyrolysis was performed in a flow reactor at low pressure (4.0 kPa) in the temperature range of 623–973 K. The pyrolysis species was detected with the tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry (MBMS). Species from m/z = 15–87 were identified from near-threshold photoionization efficiency (PIE) spectra, such as radicals of CH 3 , C 2 H 5 , C 3 H 5 and C 3 H 7 ; isomers of C 2 H 4 O (ethenol and acetaldehyde), C 3 H 6 O (acetone and propanal), C 4 H 10 (butane and isobutane), HNC (hydrogen isocyanide), HCN (hydrogen cyanide)), C 3 H 5 N (ethyl isocyanide and species with unidentified structure) and C 3 H 5 NO (methoxyacetonitrile and species with unidentified structure). Their mole fraction profiles were evaluated at different temperature. Based on the mole fractions of species measured at the minimum temperature of 1-NP pyrolysis, some new channels of 1-NP primary pyrolysis were speculated, such as the channels involving O-transfer from N to C-atoms in different positions, deoxygenation, dehydrogenation and OH-abstraction. Based on the mechanisms proposed in the literature, the species produced from secondary or subsequent reactions were also discussed. These results are valuable to a further quantum mechanical calculation for a better understanding of 1-NP chemistry.
研究领域:
化学动力学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2018
·
IF 3.468
Yunwu Zheng,Lei Tao,Xiaoqing Yang,Yuanbo Huang,Can Liu,Zhifeng Zheng
The present study aims to improve the yields and selectivity of aromatic hydrocarbons in the catalytic pyrolysis of biomass by the addition of low-density polyethylene (LDPE), which has a higher hydrogen-carbon ratio than biomass. We have investigated the thermal decomposition behavior and kinetics, as well as the product distribution, of the co-pyrolysis of biomass (cellulose and pine sawdust) and plastic (LDPE) both with and without a catalyst (HZSM-5) using thermogravimetric analysis (TGA) and analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Our results, based on the weight loss difference (△ W ), show that there is a positive and synergistic interaction between the biomass and LDPE. After the addition of LDPE, the synergistic reactions inhibited catalyst coking effectively and decreased the formation of solid residues. In addition, the ZSM-5 catalyst improved the reaction activity and reduced the activation energy, although the reaction mechanism is not changed. At the same time, the Flynn-Wall-Ozawa (FWO) method was used to fit the kinetic data for both non-catalytic and catalytic co-pyrolysis of biomass and LDPE, and the activation energies ( E a ) of the cellulose + LDPE + catalyst and pine + LDPE + catalyst systems were found to be 168.81 and 185.87 kJ/mol, respectively. The co-pyrolysis of biomass and LDPE effectively improved the yield and selectivity of aromatics and increased the selectivity for benzene, toluene, xylene, and ethylbenzene (BTXE). The addition of LDPE can effectively improve the selectivity for naphthalene family products (methylnaphthalene and 2-methylnaphthalene) in the catalytic pyrolysis of biomass and decrease the content of aromatic hydrocarbons larger than C10.
研究领域:
能源科学
·
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Xiaofang Zhang,Yuhuan Li,Yang He,Debin Kong,Bern Klein,Shenghua Yin,Hongyu Zhao
Activated carbon plays an important role in the field of wastewater treatment due to its excellent adsorption, but improving the recovery and utilization efficiency of activated carbon is a major challenge for its application. In this study, lignite (LC) and poplar leaves (PL) were used as raw materials to prepare magnetic activated carbon (MAC) by co-pyrolysis and char activation modification. The adsorption performance of the product was studied. The results showed that with different blending ratios of LC and PL, a large amount of alkali metal oxides contained in PL had different promoting effects on the pyrolysis of LC. When the mass ratio of LC to PL in the mixture was 3:2, the experimental value of hydrocarbons in the obtained tar reached 53.00%, which was 7.20% higher than the calculated value. The optimal preparation conditions of MAC were determined. Under the conditions of activation temperature of 700 °C, activation time of 2 h, ZnCl 2 mass fraction of 30%, impregnation liquid–solid ratio of 3:1 and impregnation time of 16 h, the activated carbon exhibits a relatively desirable performance. The obtained products were characterized by VSM, XRD, FT-IR, N 2 adsorption and SEM. As a result, the obtained MAC exhibits a better porous structure and higher specific surface area, and Fe 3 O 4 was observed on the surface of the MAC. The adsorption performance of coking wastewater by MAC was studied. We demonstrate that the prepared MAC could effectively adsorb organic matter in wastewater. After MAC was used to adsorb the coking wastewater for 3 h, the COD concentration in the wastewater decreased from 280 to 60 mg/L, and the MAC could be effectively recovered by magnets after adsorption.
研究领域:
能源与环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2023
·
IF 6
Hongfei Bie,Junyi Luo,Jiajing Bao,Shiliang Wu,Rui Xiao
Bio-based aviation fuel has broad development prospects, but currently commercially used bio-based aviation fuel lacks aromatics and cycloalkanes , and must be mixed with traditional aviation fuels before it can be used in aero-engines. Therefore, the preparation of bio-based cycloalkanes and aromatics from lignin has attracted extensive attention. In this paper, four cycloalkanes with representative structures were selected to study their pyrolysis characteristics. They are cyclohexane , ethylcyclohexane, 1,3-dimethylcyclohexane and decalin . Then their pyrolysis characteristics were studied, the influence of branched chains and polycyclic rings on the pyrolysis characteristics was analyzed, and the pyrolysis path of the main products was deduced through the general principle of pyrolysis combined with product analysis. In addition, the main pyrolysis pathways are also calculated and verified. Finally, the pyrolysis mechanism and coking characteristics of cycloalkanes with different structures are summarized. The results showed that there were polycyclic aromatic hydrocarbons in ethylcyclohexane pyrolysis and decalin products, but cyclohexane and 1,3-dimethylcyclohexane did not appear, indicating that ethylcyclohexane and decalin had Stronger coking tendency. Bicycloalkanes and monocycloalkanes with one side chain are more prone to thermal cracking reactions, have strong heat absorption capacity, and have stronger coking characteristics, while thermal cracking of multi-side chain monocycloalkanes is not easy to coke.
研究领域:
能源生物学
·
化学工程
✓ 已验证
DOI
高影响因子
Polymers
·
2022
·Vol. 14
·期 7
·1333
·
IF 4.967
Jiatian Zhu,Yuqi Bao,Luxiong Lv,Fanyan Zeng,Dasong Du,Chen Liang,Jiayan Ge,Shuangfei Wang,Shuangquan Yao
The preparation of bio-oil through biomass pyrolysis is promoted by different demineralization processes to remove alkali and alkaline earth metal elements (AAEMs). In this study, the hydrothermal pretreatment demineralization was optimized by the response surface method. The pretreatment temperature, time and pH were the response elements, and the total dissolution rates of potassium, calcium and magnesium were the response values. The interactions of response factors for AAEMs removal were analyzed. The interaction between temperature and time was significant. The optimal AAEMs removal process was obtained with a reaction temperature of 172.98 °C, time of 59.77 min, and pH of 3.01. The optimal dissolution rate of AAEMs was 47.59%. The thermal stability of eucalyptus with and without pretreatment was analyzed by TGA. The hydrothermal pretreatment samples exhibit higher thermostability. The composition and distribution of pyrolysis products of different samples were analyzed by Py-GC/MS. The results showed that the content of sugars and high-quality bio-oil (C6, C7, C8 and C9) were 60.74% and 80.99%, respectively, by hydrothermal pretreatment. These results show that the removal of AAEMs through hydrothermal pretreatment not only improves the yield of bio-oil, but also improves the quality of bio-oil and promotes an upgrade in the quality of bio-oil.Keywords:eucalyptus;demineralization;hydrothermal pretreatment;thermostability;pyrolysis products
研究领域:
能源植物学
·
生物质能工程
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）