JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2023
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IF 6
Yuting Wu,Qilin Gui,Han Zhang,Honghong Li,Bin Li,Ming Liu,Yingquan Chen,Shihong Zhang,Haiping Yang,Hanping Chen
The first step in uncovering pyrolysis interaction is to understand the pyrolysis reaction kinetics and small-molecule product release mechanisms of biomass components. Therefore, the cross-coupled thermal decomposition properties, gaseous product release characteristics, and functional group evolution of cellulose , hemicellulose , and lignin were investigated. The reaction activation energy is shown to be lower in co-pyrolysis, and there exist optimal mixing ratios where they favor each other's thermal breakdown. When the cellulose ratio was low, dehydration reactions, as well as the cyclization and condensation processes of open-chain hexoses and pentoses , were stimulated, but these processes were hindered when the cellulose level was high. Mixing with lignin aids in the opening of cellulose rings. However, at lower lignin levels, the dehydration, demethylation , decarboxylation , and decarbonylation processes were largely hindered, and these reactions were only stimulated at greater lignin content. The pyrolysis reaction kinetics, as well as product composition and distribution, may be altered by adjusting the composition ratio of biomass. This research helps to better understand the biomass pyrolysis interaction.
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高影响因子
FUEL PROCESSING TECHNOLOGY
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2022
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IF 8.129
Anbang Xu,Xin Huang,Guangchuan Tang,Lei Tang,Changlei Qin,Zhongqing Yang,Jingyu Ran
Levoglucosenone (LGO) has shown a promising potential in the application of the sustainable chemistry. In this work, alkali metal-doped phosphotungstic acids, M 2.5 H 0.5 PW 12 O 40 (M = Li, Na, K, Rb and Cs), were synthesized and employed for catalytic fast pyrolysis of cellulose to selectively produce LGO. The results show that levoglucosan , the main precursor of LGO, was produced with a yield of 33.5 wt% by non-catalytic pyrolysis of cellulose, while LGO by catalytic fast pyrolysis of cellulose is mainly regulated by the strong/weak acid sites of the M 2.5 H 0.5 PW 12 O 40 . Increasing the atomic radius of the alkali metals from Li to Cs doping to phosphotungstic acid led to an increase of LGO yield, attaining to 15.6 wt% at 300 °C over Cs 2.5 H 0.5 PW 12 O 40 due to a high strong/weak acid site ratio. In addition, LGO yield was further enhanced to 19.2 wt% over (NH 4 ) 2 HPO 4 modified Cs 2.5 H 0.5 PW 12 O 40 as a result of an increase of moderate strong acid sites. This study provides a potential method for LGO production by catalytic pyrolysis of cellulose.
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高影响因子
FUEL
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2022
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IF 8.035
Yanpeng Ban,Lijun Jin,Yang Li,He Yang,Haoquan Hu
Compounds with different functional groups and bridged bonds have been extensively used as model compounds of carbonaceous feedstock to investigate the mechanism of catalytic pyrolysis. Aiming to understand the structure evolution mechanism of different oxygen-containing functional groups and weak-covalent bonds during catalytic pyrolysis of carbonaceous feedstocks over calcium, polyacrylic acid, polyvinyl alcohol, polyethylene terephthalate, and polymethyl methacrylate were used as model compounds. The structural characteristics, reactivity, and pyrolysis products of model compounds with and without calcium addition were investigated by using X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, and in - situ pyrolysis vacuum ultraviolet photoionization time-of-flight mass spectrometry ( in - situ Py-VUV-PIMS). The results show that calcium can form calcium complexes with the carboxyl or alcoholic hydroxyl structures in the long aliphatic carbon chain, but it has no obvious effect on the structure and reactivity of the ester groups in different compounds. The pyrolysis products analysis showed that the chemical structure and decomposition pathway of the model compounds containing carboxyl or alcoholic hydroxyl groups changed significantly after calcium addition, and a large number of carbonyl compounds appeared in the pyrolysis products. This result provides a theoretical basis for understanding the mechanism of calcium-catalyzed carbonaceous feedstock pyrolysis.
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高影响因子
ENVIRONMENTAL RESEARCH
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2023
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IF 8.3
Jing Gao,Yang Cao,Tao Wu,Yujiang Li
In this study, roasted spent HDS ash (sHDSc-A) was used for the first time to catalytically pyrolyze oily spent HDS catalysts (sHDSc) to improve the yield and quality of pyrolysis oil. The results showed that sHDSc-A promoted the decomposition of coke in oily sHDSc, resulting in the recovery of more oil and gas. Meanwhile, sHDSc-A significantly improved the quality of the pyrolysis oil. They inhibited the aromatization of alkanes to increase the saturation of the pyrolysis oil from 59.39% to 74.25% and the H/C radio from 1.62 to 1.72; promoted the decomposition of long-chain alkanes to increase the content of C11–C22 from 41.97% to 61.99%; enhanced the conversion of carboxylic acids to ketones led to the reduction of heteroatomic compounds such as N (56.10%–45.39%), S (66.95%–56.59%), and O (45.26%–26.70%) in the pyrolysis oil. The promotion of sHDSc-A in the pyrolysis process is attributed to the catalytic effect of the metal oxides in sHDSc-A. Among them, Al 2 O 3 and Fe 2 O 3 can promote decarboxylation of carboxylic acids and reduce O mobility, while MoO 3 and Fe 2 O 3 play a significant role in reducing coke and increasing pyrolysis oil. NiO can also promote methane vapor reforming, and thus increase the production of H 2 in non-condensable gas. This study achieves self-circulation of oily sHDSc with a “waste-treatment-waste” strategy that presents the advantage of value-added energy recovery and waste reuse.
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PubMed
高影响因子
INTERNATIONAL JOURNAL OF ENVIRONMENTAL ANALYTICAL CHEMISTRY
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2023
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IF 2.6
Lu-Qing Xie,Guo-Ling Zhao,Xin-Yu Jiang,Jin-Gang Yu
Novel rape seedling peel-derived biochars (BCs) prepared by vacuum pyrolysis were used as cost-saving and sustainable biosorbents for wastewater remediation. The adsorption properties of BCs for p-nitrophenol (PNP) were investigated. The results showed that BC400 prepared at 400°C possessed the highest adsorption capacity of 55.78 mg g−1 towards PNP. Scanning electron microscopy, Energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, Zeta potential analysis and Brunauer-Emmett-Teller specific surface area analyses were performed to characterise the physicochemical properties of BC samples. The microporous structure and abundant surface heteroatomic functional groups of BC400 were confirmed. The effects of adsorption conditions (contact time, temperature, initial PNP solution pH, initial PNP concentration) on the adsorption of PNP by BC400 were investigated. Adsorption behaviour was more consistent with the linear Freundlich model and linear pseudo-second-order kinetic model. Thermodynamic study showed that the adsorption of PNP on BC400 was a spontaneous endothermic process, and the disorder degree increased after adsorption. In addition, the adsorption capacities of BC400 for different phenols including hydroquinone, 3-nitrophenol, 1-naphthol (AN) and tert-butyl hydroquinone were compared, and the mechanism was also proposed. BC400 with aromatic and heteroatom-containing functional groups could interact effectively with PNP through various intermolecular interactions including π-π stacking, hydrogen bonding and electrostatic attraction. Reusability assessment indicated BC400 remained high removal rate even after 10 consecutive adsorption-desorption cycles.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2023
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IF 15.1
Jiangtao Meng,Jing Wang,Fengling Yang,Fangqin Cheng
This study proposed a novel strategy to control nitrogen oxides (NOx) precursors by directing nitrogen to adhere to the fuel-N→NH 3 →N 2 pathway. The research aimed to illuminate the regulatory effects of CaO, Fe 2 O 3 , and their mixtures on NO and N 2 O precursors (NH 3 , HCN, and HNCO) during sludge pyrolysis, further sought to establish scientific correlations with varying temperatures and differentiate their impact. The findings indicated that unlike NH 3 , HNCO is generated from the cleavage of amides, sharing its origin with HCN. Notably, the sensitivities of three conditioners to different functional groups result in distinct impacts on precursor emissions. CaO interacted with –OH and N-H functional groups, releasing NH 3 . Fe 2 O 3 , being more responsive to C-H and C-C groups, contributed to HNCO emission. At 750 °C, a CaO-Fe 2 O 3 mixture created Ca x Fe y O z , which selectively reacted with N-H and C≡N, facilitating the conversion of HNCO and HCN to NH 3 . While temperature is a crucial factor in the performance of CaO, its impact on Fe 2 O 3 is primarily confined to transformation of heterocyclic and nitrile . Below 350 °C, Fe 2 O 3 favored the evolution of nitrogen into heterocyclic compounds within tar. Conversely, above 490 °C, it inhibited the formation of nitrile in char, promoting the dehydrogenation of tar into unsaturated aromatic structures. The CaO-Fe 2 O 3 mixtures exhibited a superposition of individual effects from CaO and Fe 2 O 3 , with Ca x Fe y O z stimulating N 2 emission. Importantly, among three conditioners, Fe 2 O 3 showed the most significant abatement effect on NOx precursors, primarily through nitrogen fixation in char, nitrogen enrichment in tar, and precursor oxidation. This research contributes innovative perspectives on nitrogen regulation in nitrogen-rich fuels, the utilization of NH 3 , and effective NO and N 2 O control.
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高影响因子
Journal of Cleaner Production
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2023
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IF 11.1
Bokun Chen,Caichun Zheng,Jicheng Bi,Xuan Qu,Rong Zhang,Xinbo Liu,Yanqi Yang
Coal pyrolysis wastewater pretreatment suffers from equipment fouling and inferior mass transfer efficiency brought by low emulsified oil removal efficiency. This paper comprehensively analyzed the properties of emulsified oil and found this inadequacies attribute to its high stability and penetrability derived from high ζ potential of −33.1 mV and tiny average particle size of 114.7 nm in initial condition. H 3 O + adjustment is developed to compress diffusion layer thickness and facilitate natural coalescence of emulsified oil droplets . Results of H 2 SO 4 acidification present the peaks of average particle size sustainably stabilized between 782.9 and 1009.0 nm and emulsified oil was mostly coagulated and subsequently settled/floated without further treatment. CO 2 was selected as a suitable donor of H 3 O + to improve application potential, and flocculants was coupled with pressurized dissolved CO 2 to intensify emulsified oil removal whose optimal efficiency achieved 93.82 wt% by changing flocculant types and operation conditions. Response surface analysis results introduced emulsified oil removal efficiency reached 95.17 wt% at PAC concentration of 1065 mg/L, CPAM concentration of 20 mg/L and operating pressure of 0.67 MPag. For renovation projects with limitations, the optimal emulsified oil removal efficiency achieved 94.33 wt% at PAC concentration of 1032 mg/L, CPAM concentration of 21 mg/L and operating pressure of 0.60 MPag. Process simulation of sour gas and ammonia stripper signified that CO 2 addition has little effect on current industrial process. By comparison, the proposed approach performs high efficiency, low impact to wastewater, strong feasibility, and great prospect in pretreatment.
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高影响因子
ACS Sustainable Chemistry & Engineering
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2023
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IF 8.4
Sijie Li,Yuan Xue,Yixi Lin,Bing Wang,Xi Gao
Plastic recycling through thermochemical conversion for the production of fuels and chemicals is a promising way for simultaneous waste processing and utilization. In the current study, high-density polyethylene (HDPE) was subjected to pyrolysis and then catalytic upgrading to produce hydrogen in the presence of a novel Fe2O3/Al2O3 catalyst with a grain boundary. To understand the catalyst–support interaction as well as the resulting synergistic catalytic effects, catalytic pyrolysis of HDPE with supported Fe2O3/Al2O3 was compared with those over Fe2O3, Al2O3, and a cascade combination of both. It was found that the performance of Fe2O3/Al2O3 was superior to that of other catalysts in terms of chain cracking and C–C/C–H bond cleavage. The hydrogen yield with Fe2O3/Al2O3 was 50.53 mmol·gplastic–1, equivalent to more than 70% of hydrogen in plastic. Besides, alkanes/alkenes ranging from C2 to C9 dominated the hydrocarbon products. The analysis of the cycle performance revealed that the reduction pathway of Fe2O3/Al2O3 was different from those of other Fe2O3-containing catalysts, which was also confirmed by temperature-programmed reduction. To investigate the essential role and reaction mechanism with Fe2O3/Al2O3, characterizations of Fe2O3/Al2O3 before and after the reaction were conducted. The grain boundary between Fe2O3 and Al2O3 enhanced the adsorption of gaseous products. More importantly, the catalyst–support interaction to form FeAl2O4 during the pyrolysis reaction, determined by X-ray photoelectron spectroscopy, was responsible for effective proton adsorption and C–H bond cleavage. This study provides an insightful understanding of catalyst transformation during plastic catalytic pyrolysis for hydrogen production.
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高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2023
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IF 6
Yuting Wu,Yadong Wang,Peiao Chen,Yang Yang,Ziyue Tang,Yingquan Chen,Haigping Yang,Hanping Chen
In order to reduce nitrogen emissions during municipal sewage sludge (MSS) pyrolysis, the effects of co-pyrolysis of MSS with biomass and the second adsorption of KH 2 PO 4 -modified biochar were investigated. It was found that co-pyrolysis with cellulose inhibited the conversion of nitrogen into pyrolytic gas, and increased the N content in pyrolytic biochar. And the nitrogen fixation rate increased with cellulose addition increasing. Besides, compared with different biomass, MSS co-pyrolysis with 30% sugarcane bagasse had the optimal effect on nitrogen fixation (39%). Moreover, KH 2 PO 4 -modified biochar addition increased the second adsorption of nitrogenous volatiles and fixed nitrogen into oxides-N. The total nitrogen fixation rate reached maximum (47.65%) at 5% KH 2 PO 4 impregnation. Thus, it is an effective nitrogen fixation method that MSS co-pyrolysis of 30% sugarcane bagasse with the second absorption of 5% KH 2 PO 4 -modified biochar. This study provided an effective solution to improve the treatment of municipal sewage sludge by pyrolysis technology.
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高影响因子
Journal of Cleaner Production
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2022
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IF 11.072
Yongkui Yang,Xiao Luo,Jie Zhang,Xiaoke Ma,Peizhe Sun,Lin Zhao
The effects of co-pyrolyzed sewage sludge–coconut fiber biochar on heavy metal stabilization and antibiotic adsorption capacity have not yet been thoroughly investigated. The present study found that Zn and Cd levels were remarkably reduced in the acid-soluble and reducible fractions in sludge after co-pyrolysis with coconut fiber , whereas their levels increased significantly in the residual fraction, thereby reducing the ecological risk of biochar. Kinetics and Freundlich models of the adsorption of ciprofloxacin (CIP) onto biochar indicated chemisorption and multilayer processes. Negative enthalpy (ΔH 0 ) and Gibbs free energy (ΔG 0 ) values indicated that CIP adsorption was an exothermic and spontaneous reaction. The synergistic mechanisms of heavy metal stabilization and CIP adsorption of this biochar are caused by the formation of crystal structures, complexation of functional groups, electrostatic interactions, and pore filling. The sewage sludge–coconut fiber biochar reduces the risk posed by heavy metals and has demonstrated a higher capacity for adsorbing CIP from water.
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高影响因子
FUEL
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2022
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IF 8.035
Wenran Gao,Yiling Wan,Shanhui Zhao,Muhammad Asif Akhtar,Kuan Ding,Bin Li,Yinlong Wu,Shoujun Zhang,Shu Zhang
Ketonization of biomass-derived oxygenates is promising for sustainable production of platform chemicals, but the catalyst activity will be severely inhibited by furanic compounds. To investigate the mechanism of the inhibition effect, furanic compounds with different side functional groups were chosen for co-ketonization with propanoic acid over CeO 2 . Results from 12 h continuous reaction showed that conversion of propanoic acid changed slightly when furan was co-fed with propanoic acid, while decreased significantly from 100 % for sole propanoic acid feeding to <55 % when co-feeding with furfural and furfuralcohol. Therefore, the inhibition ability followed the order of furfural ≈ furfuralcohol ≫ furan, which agreed well with the coke yield on the spent catalysts (51 %, 47 %, and 22 %, respectively). DFT calculation indicated that furfural and furfuralcohol, with the adsorption energy of 17–19 kJ·mol −1 , were much easier to adsorb on the catalyst than furan (11 kJ·mol −1 ). However, the lack of α-H of these furanic compounds led to their conversion into aromatic coke components. It is evidenced that the oxygenated side groups, rather than the furan ring, are responsible for the inhibition effect. Successive ketonization-combustion-ketonization tests revealed that simple air calcination can hardly recover the activity of the spent CeO 2 . This investigation gives new insights into the inhibitory impact of furans on the ketonization activity.
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高影响因子
Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Shuai Guo,Lidong Liu,Xin Guo,Tiecheng Liu,Xingcan Li,Guangyu Li
Municipal sewage sludge poses environmental and health risks, and thus, requires proper disposal using pyrolytic techniques. However, these techniques are hindered by the production of NH 3 and HCN (NO x precursors) by the sludge. Hence, a comprehensive understanding of NH 3 and HCN formation during sludge pyrolysis is required to minimize its NO x footprint. As sludge N mainly occurs in proteins forms, its transformations can be modeled using amino acids. Here, we aimed to the study the mechanism by which carbohydrates influence the formation of NO x precursors during sludge protein pyrolysis at different temperatures using glutamic acid , tyrosine, and histidine as protein models and cellulose and lignin as carbohydrate models. During pyrolysis, the release of NH 3 and HCN was promoted by high temperatures and inhibited by carbohydrates. Despite this inhibitory effect, the results suggested that the release of NH 3 should be considered for samples rich in aliphatic amino acids. For glutamic acid and tyrosine, NO x precursor formation was inhibited by N fixation in coke under the action of volatiles produced during carbohydrate pyrolysis. For glutamic acid, adding cellulose and lignin increased the coke-N content by 25.32% and 44.73% at 700 ℃. For histidine, this effect was ascribed to the ring-opening reactions induced by the free radical products of carbohydrate decomposition and the enhanced transfer of N-containing compounds to tar after ring-opening recombination. Further, heterocyclic-N within tar increased to 69.12% due to lignin-histidine interactions at 700 ℃. The results of this study can assist in regulating sludge protein pyrolysis intended for minimizing the production of NO x precursors.
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高影响因子
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