JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2023
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IF 6
Ziyue Tang,Yingquan Chen,Juping Liu,Wei Cheng,Xianhua Wang,Qiang Hu,Yang Yang,Haiping Yang,Hanping Chen
There is significant effect on thermal behaviors pyrolytic characteristics of the interactions between microalgal components. In order to understand the reaction process, interaction mechanism, and better utilization of microalgae, co-pyrolysis of microalgal model compounds (soybean protein (PT), sunflower oil (OL) and sucrose (SC)) was carried out with TG-FTIR and Py-GC/MS. The results showed that co-pyrolysis of PT and SC significantly changed the thermal behaviors, and accelerated decomposition at lower temperature to generate C O, CO 2 largely. And it could promote the generation of linear O-compounds (such as acetic acid), and inhibit the formation of N-heterocycles and furans. Moreover, OL co-pyrolysis with PT or SC could significantly promote the formation of long-chain acid and inhibit the generation of aliphatics. Meanwhile, co-pyrolysis of PT and OL inhibited the generation of N-heterocycles. And co-pyrolysis of SC and OL accelerated the generation of furans. Furthermore, co-pyrolysis of model compounds reduced the average activation energy of the pyrolysis process, and changed the reaction kinetic model.
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Biofuels Bioproducts & Biorefining-Biofpr
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2023
·Vol. 17
·期 6
·1698-1707
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IF 3.9
Chao Liu,Zhanghong Xie,Lili Tong,Yuyang Fan,Xiangchen Kong,Rui Xiao
In this study, a sealable fixed-bed reactor was developed to investigate the influence of gaseous products on lignin pyrolysis with a strategy of hydrogen self-supply, and lignin pyrolysis performances at various temperatures were monitored by the comprehensive characterization of the generated products, including gas, bio-oil and char. The results showed that the release of volatiles (both gas and bio-oil) from lignin was strengthened in this sealable system when the temperature rose, and therefore less char was left. Meanwhile no H 2 was detected under any of the operating conditions, which is a common component in pyrolysis gas from conventional reactors, indicating its participation in lignin pyrolysis. Furthermore, the formation of CO and CO 2 in the employed pyrolyzer benefited from not only the thermal evolution of feedstock, but also the interactions between char residues and generated gas components. Meanwhile, because of the hydrogen self-supply, compounds in bio-oil were enriched and only nine species were detected, which were all phenolic compounds. Vanillic acid was dominant, and its relative content was up to 38.86% for Alcell organosolv lignin and 34.41% for soda alkali lignin. This illustrates that highly selective production of phenolic compounds from lignin pyrolysis can be achieved by self-supplying hydrogen from pyrolysis gas.
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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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FUEL
·
2023
·
IF 7.4
Yang Shen,Chunjiang Liu,Cunhao Cui,Hairong Ren,Mingming Gu,Haoran Liu,Zhongyue Zhou,Fei Qi
Lignin catalytic pyrolysis presents a promising and sustainable approach to producing aromatic molecules. Herein, we investigated the effect of modified zeolite with copper (Cu/HZSM-5) catalyst on efficiently pyrolyzed kraft lignin into aromatic hydrocarbons (AHs) production, especially mononuclear aromatic hydrocarbons (MAHs). Time-of-flight mass spectrometry (TOF-MS) was employed to compare the volatile product profiles of lignin during catalytic pyrolysis. The highest yield of MAHs reached 70.59 mg/g based on dry lignin at 550 °C, accounting for 70.23% among lignin pyrolysis products, compared to the pristine HZSM-5 zeolite catalytic system with MAHs yield of only 54.31 mg/g and of 40.34% in products. At 550 °C and 60 s residence time, the 5% Cu/HZSM-5 catalyst demonstrated the best performance compared to all other catalysts in terms of selectively producing MAHs. The results are ascribed to the enhancement of decarboxylation and aromatization processes by the doping of copper. This work demonstrates a cost-effective pathway that potentially converts kraft lignin into aromatic hydrocarbon production at a phenomenally high selectivity, providing a concept for industrial application toward biomass utilization and high value-added production.
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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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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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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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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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COMBUSTION AND FLAME
·
2023
·
IF 4.4
Jinhu Liang,Chen Zhao,Ziwen Zhao,Xinhui Wang,Ming-Xu Jia,Quan-De Wang,Yang Zhang,Fengqi Zhao
Amine compounds are an important class of nitro-containing fuels and represent as promising renewable fuels . However, the structural effect from the alkyl group on the combustion characteristics of amines remains an urgent problem to promote their usage in practical engines. To probe and replenish the combustion properties of amine fuels, this work reported an experimental and kinetic modeling study on the high-temperature ignition and pyrolysis characteristics of cyclohexylamine over a wide range of conditions. Specifically, a high-pressure shock tube is used to measure the ignition delay times under the temperature range from 1100 K to 1700 K with pressure of 2 and 5 bar and the equivalence ratios of 0.5, 1.0 and 2.0. The pyrolysis characteristics is studied using a single-pulse shock tube at fuel concentration of 0.5% diluted by argon in the temperature range 950–1400 K at 5 and 10 bar with the residence time around 1.6 microsecond . A detailed kinetic mechanism is developed to simulate the experimental results. To improve the accuracy of the detailed mechanism, primary initial reactions of cyclohexylamine including the hydrogen abstraction reactions and the C N decomposition reaction are theoretically studied at G4//M06–2X/6–311++ G (d, p) level of theory with transition state theory and RRKM/mater equation. The detailed kinetic mechanism shows good prediction accuracy of the ignition delay times and pyrolysis product distributions under different temperature, pressure and equivalence ratio conditions. Sensitivity analysis results indicate that the most sensitive reaction is O 2 + H = O + OH with the most negative sensitivity coefficient and the abstraction reaction of vinylamine with OH radical, C 2 H 3 NH 2 + OH = C 2 H 3 NH + H 2 O also exhibits large sensitivity coefficients. Reaction path analysis reveals that the abstraction reactions control the initial oxidation of cyclohexylamine and cyclohexen-1-amine, cyclohexen-2-amine, and cyclohexen-3-amine are also major intermediates during the oxidation of cyclohexylamine besides small pyrolysis products.
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POLYMER DEGRADATION AND STABILITY
·
2023
·
IF 5.9
Shi-yu Feng,Kai Li,Zhu-yu Li,Dong-hong Nan,Yan-qin Huang,Ji Liu,Qiang Lu
A green way for the sustainable utilization of waste polycarbonate (PC) was developed, i.e., NaOH solution-assisted pyrolysis to co-produce phenolic compounds and supercapacitor material. A lab-scale setup was employed for the pyrolysis of PC to explore the regulation effects of NaOH concentration and pyrolytic temperature on the production of phenol and 4-isopropenylphenol (IPP). The yields of phenol and IPP were up to 35.3 wt% and 29.9 wt% at 600 °C and NaOH concentration of 0.5 mol/L, which were much higher than those from pure PC pyrolysis (7.2 wt% and 3.6 wt%). Furthermore, the pyrolytic solid residue was directly subjected to the high-temperature activation to prepare activated carbon, which could be used as a supercapacitor material with an outstanding specific gravimetric capacitance of 182.1 F/g at 1 A/g.
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FUEL PROCESSING TECHNOLOGY
·
2022
·
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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ENERGY & FUELS
·
2018
·
IF 3.024
Zihao Zhang,Hao Cheng,Hao Chen,Jing Li,Kequan Chen,Xiuyang Lu,Pingkai Ouyang,Jie Fu
Hierarchical HZSM-5 with tunable acidity, zeolitic crystallinity, and porosity were prepared using different organosilanes and used for the production of aromatics from the catalytic fast pyrolysis (CFP) of rice straw. As the chain length of organosilanes changed, the composition of the products including aromatics and coke varied greatly. Additionally, the introduction of ammonium ions into organosilanes led to a lower yield of aromatics and a higher yield of coke. Transmission electron microscopy, temperature-programmed desorption of NH3, N2 adsorption–desorption (Brunauer–Emmett–Teller), and X-ray diffraction were used to explore the influence of the morphological structure, acidity distribution, textural properties, and crystallinity on the CFP of rice straw. The results indicated that the crystallinity, textural properties, and total acidity had a great influence on the synthesis of aromatics.
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危险品化学品经营许可证（带存储）