Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
A research paper
Preparation of porous materials by ultrasound-intensified acid leaching of high-carbon component in coal gasification fine slag
LI Cuicui, HAN Rui, ZHOU Anning, ZHANG Ningning, GUO Kaiqiang, CHEN Heng, CHEN Xiaoyi, LI Zhen, WANG Junzhe
 doi: 10.1016/S1872-5813(23)60402-5
Abstract(33) HTML(30) PDF 12977KB(6)
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Coal gasification fine slag is one of the by-products from the process of clean and efficient utilization of coal, and its resource application is imminent. In this study, a high carbon fraction with a fixed carbon content higher than 60% was obtained by simple sieving of gasification fine slag, and a porous material was prepared from it by ultrasonic acid leaching method. The adsorption treatment of radioactive iodine in nuclear wastewater is taken as the application background, and the adsorption performance of porous materials is characterized by iodine adsorption value. The effects of ultrasound time, ultrasound power, acid concentration, and temperature on the iodine adsorption performance and compositional structure of the porous materials were systematically investigated by combining the analytical methods of SEM, BET, XRD and FT-IR, while the mechanisms of ultrasound-enhanced acid leaching protocols on the compositional structure of residual carbon and the migration and transformation laws of the ash constituents were explored, and the mechanism of the ultrasound-enhanced action in this process was summarized. The results showed that the porous material prepared under the conditions of acid concentration of 4 mol/L, acid immersion temperature of 50 ℃, ultrasonic power of 210 W, and ultrasonic time of 1.5 h had the best iodine adsorption performance of 468.53 mg/g, with a specific surface area of 474.97 m2/g, and it possessed a rich pore structure with predominantly mesopores. The order of the effect of each factor on the iodine adsorption performance of the porous materials was: sonication time > acid concentration > sonication power > acid immersion temperature. The mechanism of ultrasonic enhanced acid leaching is that ultrasonic cavitation and mechanical wave action will firstly enhance the dissociation of carbon-ash adherent particles, thus making the ash particles blocked in the pore channels of gasification slag desorption to increase the connectivity of the pore structure; secondly, lead to the generation of cracks on the surface of the carbon and ash particles to enhance the accessibility of the inorganic components inside the carbon particles; and thirdly, enhance the acid leaching process by increasing the mass transfer rate to strengthen the leaching effect of the inorganic components in the gasification slag.
A research paper
Electrocatalyst hydrogenation of lignol-derived compounds: Conversion regularity and product selectivity
WEI Dening, TANG Hongbiao, YANG Gaixiu, YANG Juntao, LI Ning, CHEN Guanyi, CHEN Chunxiang, FENG Zhijie
 doi: 10.1016/S1872-5813(23)60405-0
Abstract(25) HTML(7) PDF 1138KB(8)
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Phenolic derivatives, crucial components of bio-oil, require thorough understanding of their electrocatalytic hydrogenation (ECH) properties for efficient bio-oil utilization. This study investigated guaiacol, a representative phenolic derivative in bio-oil, focusing on its ECH mechanism, conversion, and product selectivity under varied conditions (temperature: 40−80 °C, perchloric acid concentration: 0.2−1.0 mol/L, current intensity: ((−10)−150 mA). Additionally, this study also explored the influence of intermediate products (2-methoxycyclohexanone and cyclohexanone) on both the conversion rate and the selectivity of the products. The experiment had revealed that guaiacol's ECH conversion rate improved with higher temperature and current intensity, whereas an increase in perchloric acid concentration negatively affected the conversion. Significantly, the presence of intermediate products, especially 2-methoxycyclohexanone, markedly enhanced the ECH conversion of guaiacol. Investigating further into the ECH mechanism of other phenolic derivatives, including phenol, pyrocatechol, guaiacol eugenol, and vanillin, as well as their combination, revealed a trend where conversion rates inversely correlated with the complexity of the functional groups on the benzene ring. Specifically, phenol, with its simpler structure, showed the highest conversion rate at 89.34%, in stark contrast to vanillin which, owing to its more complex structure, exhibited the lowest at 46.79%. In our multi-component mixture studies, it was observed that synergistic and competitive interactions significantly alter ECH conversion rates, with some mixtures showing enhanced conversion rate indicative of synergistic effects.
review
Recent advances in preparing biomass-based 2,5-bis(hydroxymethyl)furan by catalytic transfer hydrogenation
LI Wei, GONG Honghui, SHI Xianlei
 doi: 10.1016/S1872-5813(23)60403-7
Abstract(118) HTML(40) PDF 36414KB(37)
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Biomass-based 2,5-bis(hydroxymethyl)furan (BHMF) is one of the important high value-added chemicals, which can be prepared from inexpensive and renewable carbohydrates through the way of catalytic conversion and selective hydrogenation, and as a widely used chemical intermediate and fuel precursor, it has unique advantages in improving the performance of traditional polyesters and synthesizing new biodegradable bio-based polyesters. In recent years, the research on the production of high value-added chemicals such as BHMF from carbohydrate has been attracting much attention from both academia and industry. However, cleanliness, high efficiency, high selectivity and low-cost remain key challenges in this area, especially for practical applications. In the process of BHMF production, the traditional hydrogenation method consumed a large amount of high-grade energy of hydrogen, and an excessive investment in infrastructure would be generated due to the security risks of higher pressure of hydrogen. On account of the advantages of catalytic transfer hydrogenation, the advances in selective hydrogenation to prepare BHMF using formic acid, alcohols and other types of hydrogen donors by the approach of catalytic transfer hydrogenation is systematically discussed in this review. In view of the features and problems of different types of hydrogen donors, catalysts and reaction processes during the catalytic transfer hydrogenation process, the effects of reaction conditions and process intensifications on the selectivity and yield of BHMF, and the merits and demerits of the reaction system were all investigated. On this basis, the future directions of new catalytic systems for preparation of BHMF by transfer hydrogenation is proposed, and the cleaner, more efficient and essential safety technologies for the production of BHMF is predicted, which will provide some scientific reference for the research and development of related catalytic systems in biomass conversion.
A research paper
Enhanced electro-catalytic activity of TNTs/SnO2-Sb electrode through the effect mechanism of TNTs architecture
YANG Lisha, GUO Yanming
 doi: 10.1016/S1872-5813(23)60390-1
Abstract(59) HTML(17) PDF 13063KB(7)
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The TiO2 nanotubes arrays/SnO2-Sb (TNTs/SnO2-Sb) electrode is successfully fabricated using the solvothermal synthesis technique. Various architectures of TNTs are constructed by varying the anodization voltage and time, aiming to investigate their impact on the structural and electrochemical properties of the SnO2-Sb electrode. The anodization voltage is identified as the primary influencing factor on the morphology and surface hydrophilia of TNTs arrays, which is evidenced by scanning electron microscopy (SEM) and contact angle testing. In contrast, the effect of anodization time is relatively small. SEM, X-ray diffraction (XRD), linear sweep voltammograms (LSV), and electrochemical impedance spectroscopy (EIS) results indicat that the morphology and crystal size of the catalytic coating, as well as the oxygen evolution potential of the electrode, are influenced by the pore size of TNTs arrays. The influencing mechanism of enhanced electrochemical activity by adjusting the architecture of TNTs arrays is investigated using X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and Hydroxyl radicals (·OH) generation test. The results reveal a higher concentration of oxygen vacancies on the sample with a compact and smaller particle coating, indicating the presence of more adsorbed oxygen species. Consequently, this enhancs the generation capacity of active radicals for organic matter degradation. The electrode featuring TNTs arrays with a length of 950 nm and a pore diameter of 100 nm exhibits the most effective remediation of phenol-containing wastewater, achieving approximately 92% ± 4.6% removal after a duration of 2 h.
Ni supported on Ti-doped SBA-15 catalyst for the selective hydrodeoxygenation conversion of lignin derivatives
ZHANG Hongke, WANG Weichen, XIANG Zhiyu, ZHOU Fangyuan, ZHU Wanbin, WANG Hongliang
 doi: 10.1016/S1872-5813(23)60387-1
Abstract(65) HTML(13) PDF 9736KB(10)
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The development of cost-effective and efficient catalysts plays a critical role in the selective hydrodeoxygenation of lignin derivatives for lignin valorization. Herein, we reported “metal-acid” bifunctional catalysts (Ni/Ti-SBA-15) consist of Ni nanoparticles highly dispersed on Ti doped SBA-15, which achieved 100% vanillin conversion and 96.46% selectivity of 2-methoxy-4-methylphenol (MMP) under mild conditions. Characterizations were employed to reveal the morphology and physicochemical properties of the catalysts. The results indicated that doping of Ti species not only increased the number of acidic sites but also promoted the high dispersion of Ni nanoparticles on the support. This research provides a novel concept for the synthesis of cost-effective and efficient catalysts, which contributes to the environmentally friendly and economical conversion of biomass derivatives.
A research paper
Photo-induced in situ synthesis of Cu2O@C nanocomposite for efficient photocatalytic evolution of hydrogen
LI Na, MAO Shuhong, YAN Wenjun, ZHANG Jing
 doi: 10.1016/S1872-5813(23)60400-1
Abstract(68) HTML(28) PDF 12138KB(13)
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Cuprous oxide (Cu2O) is an ideal visible light catalyst owing to its narrow band gap, environmental benignity and abundant storage; however, the fast recombination of photogenerated charge carriers and poor stability of Cu2O has impeded its application in photocatalysis. Herein, we demonstrate that Cu2O@C nanocomposite can spontaneously evolve from a methanol aqueous solution containing cupric ions under the induction of irradiation. Compared with the traditional carbon coating method, the Cu2O@C nanocomposite obtained by the photo-induced in-situ synthesis can reserve superior original characteristics of the semiconductor under mild reaction conditions, promote the charge transfer and enhance the separation efficiency of charge carriers; in addition, the carbon shells can also effectively prevent Cu2O from photo-corrosion. As a result, the Cu2O@C nanocomposite exhibits excellent photocatalytic activity in the hydrogen evolution in comparison with the Cu2O particles; the H2 evolution rate over the Cu2O@C nanocomposite reaches 1.28 mmol/(g·h) under visible light, compared with the value of 0.065 mmol/(g·h) over Cu2O. Moreover, the Cu2O@C nanocomposite displays good cycle stability, viz., without any deactivation in the catalytic activity after five cycles.
Preparation of eggshell supported Co3O4 catalyst and tested for N2O decomposition
HU Xiaobo, FENG Linyan, WU Ruifang, WANG Yongzhao, ZHAO Yongxiang
 doi: 10.19906/j.cnki.JFCT.2023079
Abstract(39) HTML(15) PDF 20890KB(5)
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A series of Co3O4/eggshell catalysts with different Co3O4 contents were prepared by the deposition-precipitation method using discarded eggshells as supports, and tested for the catalytic reaction of N2O decomposition on a fixed-bed continuous flow micro-reactor. The activity test results show that the catalyst exhibits higher activity towards N2O decomposition when the mass fraction of Co3O4 is 20%, with a specific activity of 4.3 times to that of pure Co3O4 (reaction temperature 440 ℃). At the same time, it shows strong resistance to 3% O2, 3.3% H2O and/or 2.0×10−4 NO in feed. Various characterization results indicate that the predominant composition of eggshell is CaCO3, which has a close incorporation with Co3O4. The strong interaction between CaCO3 and Co3O4 contributes to producing more oxygen vacancies and Co3+ in the 20% Co3O4/eggshell catalyst. The redox performance of Co3O4 is improved, and the Co−O bond is effectively weakened. In addition, it helps to increase the strength and amount of basic sites on the catalyst surface, making it easily transfer electrons and promote N2O decomposition.
A research paper
Preparation of Co/Zr/Al2O3-Pt/ZSM-5 catalysts for syngas to liquid fuels
LI Hang, ZHANG Yuhua, XIANG Rong, AI Xinyan, YAN Haoyu, LIU Chengchao, LI Jinlin
 doi: 10.19906/j.cnki.JFCT.2023087
Abstract(43) HTML(12) PDF 42585KB(8)
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The Co catalysts exhibit high catalytic activity and low water gas shift activity, as well as excellent chain growth ability and low by-product selectivity for Fischer-Tropsch synthesis. The performance of the Co catalyst is influenced by several factors, including its structural composition and physical and chemical properties. The traditional cobalt Fischer-Tropsch catalyst follows the ASF distribution, resulting in a wide range of hydrocarbon products. This makes it difficult to achieve high selectivity for liquid hydrocarbons. Due to the presence of a large number of acidic sites on the surface of zeolite, it has excellent catalytic performance for hydrocracking. The integration of zeolite molecular sieves with Fischer-Tropsch catalysts to form a multi-component catalyst can significantly improve product selectivity, optimize liquid hydrocarbon yields and bypass conventional wax treatment steps. In this study, the catalysts Co/Al2O3, Co/Zr/Al2O3 and Co/Zr/Al2O3-Pt/ZSM-5 were prepared by ultrasonic dispersion method, and the effects of Zr promoter modification and multicomponent coupling catalyst on the activity and product selectivity of Fischer-Tropsch synthesis were investigated. In Co/Al2O3, Co/Zr/Al2O3 and Co/Zr/Al2O3-Pt/ZSM-5 catalysts, the Co species are uniformly dispersed on the support surface and have similar particle sizes. Pt and Zr were uniformly dispersed in the catalyst, Zr was mainly dispersed on the surface of Al2O3 supports, and Pt was mainly dispersed on the surface of ZSM-5 molecular sieve. The reduction of Co species was promoted by Zr-modified alumina. With the addition of Pt/ZSM-5 catalyst, the adsorbed hydrogen is more easily dissociated and converted into active hydrogen, further promoting the reduction of Co species. The catalytic performance of Fischer-Tropsch synthesis was evaluated. Compared with Co/Al2O3 catalyst, the selectivity of C12+ heavy hydrocarbon products on Co/Zr/Al2O3 catalyst increased from 28.2% to 38.1%, with a corresponding decrease in CH4, C2−C4 and C5−C11 products, indicating that Zr promoter promoted the generation of heavy hydrocarbon products. Coupled with Pt/ZSM-5 catalyst, the Co/Zr/Al2O3-Pt/ZSM-5 catalyst showed low CH4 selectivity (10.0%) and C2−C4 selectivity (15.0%), while the selectivity of C5−C11 liquid hydrocarbon products increased from 32.1% to 45.9%, the selectivity of heavy hydrocarbon products (C12+) decreased from 38.1% to 29.1%. Compared to Co/Zr/Al2O3, the TOF and CTY of Co/Zr/Al2O3-Pt/ZSM-5 catalysts are increased by 212.6% and 62.7%, respectively. The improvement in catalytic activity was mainly due to the addition of Zr promoter and Pt/ZSM-5 catalyst, which promoted the reduction of Co species. Under the synergistic effect of Zr promoter and Pt/ZSM-5 catalyst, Zr promoter promotes the formation of C12+ heavy hydrocarbons, while Pt/ZSM-5 catalyst promotes the hydrocracking of heavy hydrocarbons to C5−C11 liquid hydrocarbons, thereby improving the selectivity of Co/Zr/Al2O3-Pt/ZSM-5 catalyst for C5−C11 liquid hydrocarbons. In this study, a functional catalyst was constructed by coupling Fischer-Tropsch synthesis catalyst and hydrocracking catalyst at nanoscale, which achieved high selectivity of C5−C11 liquid hydrocarbon and low selectivity of CH4 and C2−C4 products, which provided a reference for the design and implementation of catalysts with high selectivity for liquid hydrocarbons.
review
Research progress of SCR medium temperature denitrification catalyst for cement industry
HAN Yuxuan, ZHOU Yu, TAN Chenchen, WU Peng, DING Shipeng, SHEN Kai, ZHANG Yaping
 doi: 10.19906/j.cnki.JFCT.2023084
Abstract(22) HTML(12) PDF 10309KB(3)
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Selective catalytic reduction (SCR) technology has been widely used in the denitrification of cement industry, in which a relatively mature system has been formed in the high temperature(280–350 ℃) section, but there is still a breakthrough in the middle temperature zone. Focusing on medium temperature catalysts, this paper reviewed the progress of Mn, Ce and V catalysts, and analyzed the doping of Sm, Nb, Ho, Sb, La, Mo and Pr to improve the performance of catalysts. Combined with the characteristics of the high content of SO2, H2O and alkali metal in cement kiln smoke, the causes of catalyst poisoning were analyzed, summarize the way to resist sulfur poisoning, water poisoning, and alkali metal poisoning. The research prospect of SCR medium temperature denitration catalyst in cement industry is prospected.
Methane catalytic combustion over flame spray pyrolysis-synthesized Pd-Pt/CeO2 catalyst
WU Linyuan, WANG Yi, CHEN Zhaoying, TIAN Qingling, WANG Linru, FU Zijun, ZHAO Ning, WANG Xiaobo, HUANG Xin
 doi: 10.19906/j.cnki.JFCT.2023083
Abstract(49) HTML(26) PDF 26776KB(11)
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Flame spray pyrolysis (FSP) is a versatile, rapid, and scalable preparation technique for the nanocatalysts. CeO2 and Pt-CeO2 carriers, Pd-Pt-CeO2 catalyst were synthesized by flame spray pyrolysis, and then Pd-Pt bimetallic catalysts were prepared by impregnation method, and as-obtained Pd-Pt catalysts were tested in the methane combustion. The physicochemical properties of the catalysts were characterized by ICP, XRD, TEM, BET, H2-TPR, XPS, and Raman. TEM results showed that Pd and Pt species were highly dispersed in CeO2 carriers in Pd-Pt/CeO2 catalysts. Compared with the Pd-Pt-CeO2(OS-FSP) catalyst prepared by one-step flame spray pyrolysis, the catalytic activity of the Pd-Pt/CeO2(0.25)-WI prepared by co-impregnation was higher, with its t50 reduced by 60 ℃, and no deactivation was seen for 60 h. It is attributed to the fact that the Pd-Pt/CeO2(0.25)-WI catalyst has a higher molar ratio of Pd0/Pd2+ and Ce3+/Ce4+ on the surface of the catalyst and more lattice oxygen, resulting in an excellent performance during the methane combustion.
A research paper
Preparation and oxidation desulfurization performance of Zirconium oxychloride based ternary deep eutectic solvent
WANG Tianbo, LI Xiuping, ZHAO Rongxiang
 doi: 10.19906/j.cnki.JFCT.2023085
Abstract(31) HTML(9) PDF 1841KB(8)
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A zirconium oxychloride based ternary deep eutectic solvent (DES) was prepared by simply heating mixture of ethylene glycol, p-toluenesulfonic acid and octahydrate zirconium oxychloride. The successful synthesis of deep eutectic solvents was verified using Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectroscopy (1H NMR). The acidity and viscosity were tested using UV-visible absorption spectroscopy and rotary viscometer, respectively. The extraction- oxidation desulfurization system was composed of hydrogen peroxide as the oxidant, deep eutectic solvent as the extractant and catalyst. The effects of the composition of the deep eutectic solvent, reaction temperature, oxygen sulfur ratio, solvent oil ratio, and different sulfides on the desulfurization rate were investigated. The experimental results showed that the desulfurization rates of dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), and benzothiophene (BT) simulated oil were 100%, 92.2%, and 60%, respectively, under the optimal reaction conditions of a molar ratio of 1:10:10 between zirconium oxychloride, ethylene glycol, and p-benzenesulfonic acid components, 50 ℃, a solvent oil ratio of 1∶5, and an oxygen sulfur ratio of 8. After repeated use of the deep eutectic solvent for 5 times, the desulfurization rate could still reach 96.2%. The mechanism of oxidative desulfurization was explored.
Soluble conversion of Zhaotong lignite by ammonolysis and the occurrence forms of oxygen and nitrogen in soluble portion
REN Yuyao, ZHOU Guoli, LIU Haojie, TENG Daoguang, CAO Yijun, XING Baolin, LI Peng
 doi: 10.19906/j.cnki.JFCT.2023088
Abstract(18) HTML(3) PDF 6104KB(2)
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Lignite is of high carbon content, rich in oxygen and nitrogen, and other heteroatoms, thereby is treated as an important raw material for the preparation of carbon materials. However, the preparation of carbon materials from lignite is faced with many challenges, due to the low soluble organic carbon content and the irregular distribution of heteroatoms. In this investigation, ammonia was applied to achieve the solubilization of Zhaotong lignite, and also the regulation of oxygen and nitrogen in soluble portion from lignite under mild conditions. As a result, Zhaotong lignite exhibits efficient thermal dissolution with a soluble portion yield of 76.66%, at the condition of ammonium concentration of 15%, temperature of 160 ℃, and reaction time of 3 h. Based on the characterization and analysis of soluble portion, the macromolecular structure of coal was changed by ammonolysis, mainly displayed as the replacement of hydroxyl group by amino group, or produce organic nitrogen by direct reaction with some carboxyl group and carbonyl group. By contrast, the occurrence forms of nitrogen elements in raw coal are mainly quaternary nitrogen and pyrrole nitrogen, while the occurrence forms of nitrogen elements in soluble matter are mainly amino nitrogen and pyridine nitrogen, indicating that amino or amide groups are formed during the thermal dissolution of lignite.
Study on pyrolysis mechanism and kinetics of two of spiro [4,5] decane and spiro [5,6] dodecane
WANG Hongyan, SUN Xinyue, ZHOU Yurou, LIU Guozhu, WANG Yutong, CAO Jingpei
 doi: 10.19906/j.cnki.JFCT.2024001
Abstract(18) HTML(11) PDF 2109KB(6)
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Active cooling with high-energy-density liquid hydrocarbon fuel is one of promising techniques for the thermal protection of hypersonic aircrafts. To extend the flight range and increase the payload of volume-limited aerospace vehicles, high-energy-density liquid hydrocarbon fuel is directly used as an energetic additive or liquid propellant. Among them, biomass derived spiro-fuels, shown high density, low freezing point and high net heat of combustion due to compact molecular structures, are a kind of significant high-density fuel. The investigation of thermal pyrolysis of these spiro-fuels not only significantly improves the heat sink through the endothermic reaction, but also brings the new challenges of ignition and combustion of the cracked hydrocarbon fuel. The detailed theoretical calculations and molecular dynamics simulations of spiro [4,5] decane (C10H18) and spiro [5,6] dodecane (C12H22) initial pyrolysis were performed to explore the ring-size effect on the consumption of fuels and formation of primary products. The results show that the initial decomposition paths of the two spiro-fuels are very similar, mainly consumed by the open-ring isomerization via the unimolecular C−C dissociations of the six membered ring structure and H-abstractions by small radicals attacking the fuel parents. Due to the lower C−C and C−H bond dissociation energies caused by large tension of the seven membered ring structure, C12H22 may exhibit the lower initial decomposition temperature and higher reaction activity than C10H18. The differences of simultaneously formed fuel radicals during C10H18 and C12H22 initial pyrolysis further affect the formation pathways of C1−C7 small products, cycloalkenes and monocyclic aromatics. Among them, ethylene are the most important products. Due to the presence of inherent six membered rings in two spiro-fuels, monocyclic aromatics mainly originate from multi-step dehydrogenation reactions of fuel radicals, involving benzene, toluene, styrene and ethylbenzene. Notably, the size effect of spiro-ring in two fuels leads the obvious structural differences of the formation of chain hydrocarbons and cycloalkenes. For C10H18, a large number of penta- cycloalkenes may be generated, including cyclopentadiene, cyclopentene, fulvene, methylcyclopentadiene and methylcyclopentene, whereas the seven-membered ring structure of C12H22 may produce corresponding seven-membered products (cyclohexene and methylene cycloheptane). Moreover, the pyrolysis behaviors of these two spiro-fuels at 2000 K based on the ReaxFF molecular dynamics simulation were explored and show well consistent with the main products derived from DFT theoretical calculations. This work performs the DFT theoretical calculations and ReaxFF molecular dynamics simulation on the pyrolysis kinetic mechanisms of two representative high-density biomass fuels of spiro fuels, providing a possible initial pyrolysis path and laying a theoretical foundation for their practical application in engines. However, the complex working environment of the cooling channel poses more challenges to the actual pyrolysis process of the new high-density hydrocarbon fuels. In future research, pyrolysis experiments will be conducted under high temperature and high pressure conditions, and the detailed pyrolysis kinetics models with excellent predictive performance over a wide operating range will be constructed. At the same time, research will be conducted on the subsequent ignition and combustion process of the engine combustion chamber, exploring the impact mechanism of catalysts and fuel additives on this process, assisting in the practical application of fuel, improving fuel combustion efficiency, and effectively controlling pollutant emissions.
A research paper
Synthesis and hydrocracking performance of small crystal NiY zeolites
SUN Jinxiao, WANG Xiaohan, WEI Qiang, ZHOU Yasong
 doi: 10.1016/S1872-5813(24)60432-9
Abstract(14) HTML(2) PDF 4039KB(9)
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A series of small crystal Y-xNi zeolites with different amounts of Ni doping were synthesized by an in situ synthesis method, in which Ni precursors were introduced during the synthesis of small crystal Y zeolites. The active metal Ni was pre-impregnated into the framework of the Y zeolite. Y-xNi series zeolite and ASA were mechanically mixed as support and loaded with Ni and W to prepare Cat-xNi series hydrocracking catalysts. The hydrocracking performance was investigated using n-hexadecane as the reactant. The effects of Ni doping on the physicochemical properties of Y zeolite and catalysts were analyzed by means of characterization such as scanning electron microscopy (SEM), X-ray diffraction (XRD), N2-adsorption desorption, NH3 temperature programmed desorption (NH3-TPD), H2 temperature programmed reduction (H2-TPR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results show that Ni mainly replaces Al into the framework of Y zeolite. The appropriate incorporation of Ni into Y zeolite increases the relative crystallinity of Y zeolite and the number of Brønsted and Lewis acid sites. However, excessive Ni incorporation is detrimental to the crystallization of Y zeolite and excessive non-framework Ni species will cover the surface Brønsted acid sites. Ni doping weakened the metal-support interactions, increased the sulfation of the active metal, the stacking number and dispersion of NiWS, and modified the matching between the metal and acid sites on the catalyst. The results of the catalyst evaluation showed that the introduction of Ni was favorable to improve the selectivity and yield of the middle distillate products (C8-C12). That is, increasing the number of Brønsted acid sites and NiWS active sites at the same time, improving the synergistic effect between the metal sites and the acid sites, improving the conversion while avoiding over-cracking, and increasing the yield of the middle distillate products. The catalyst Cat-0.2Ni had a higher n-C16 conversion and C8-C12 product yield at the reaction temperature of 360 ℃, with the n-C16 conversion increased by 10.2 percentage points compared with that of Cat-0Ni, and the C8-C12 product yield was 65.4%. Therefore, the pre-impregnation of active metal Ni on Y zeolite can effectively regulate the balance between the Hydrogenation and cracking performance to improve the catalytic activity and the yield of middle distillate products.
A research paper
Study on the Antioxidant property of calixarene in high density hydrocarbon fuel JP-10
YANG Yuxin, LEI Quan, CHEN Xinyang, DAI Yitong, FANG Wenjun, GUO Yongsheng
 doi: 10.19906/j.cnki.JFCT.2024002
Abstract(4) HTML(5) PDF 1341KB(2)
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Since the 21st century, hypersonic flight technology has attracted much attention.When the aircraft is flying at a high Mach number, a large amount of aerodynamic heat is generated between the air and the aircraft due to friction, resulting in a rapid increase in the temperature of the aircraft subsystem, exceeding the range that the material can withstand, affecting the flight safety of the aircraft. In order to meet the thermal management needs, an integrated cooling approach combining heat transfer and combustion has been introduced. This method utilizes hydrocarbon fuels both as propellants and coolants to absorb the excess heat from the aircraft's high-temperature components, thereby enhancing energy efficiency and managing the thermal conditions of high-speed aircraft. Fuels that satisfy this concept are called endothermic hydrocarbon fuels. However, these fuels are prone to oxidation due to heat, oxygen, and catalysis during storage and use, leading to the formation of insoluble gums and degraded performance, which may even clog the fuel system, endangering flight safety. Thus, suppressing the oxidation process of high-density endothermic hydrocarbon fuels is crucial for fuel storage and usage.Common methods to improve the oxidation stability of fuels include surface treatment, fuel deoxidation, and the addition of antioxidants to the fuel. Among these methods, adding antioxidants is one of the most commonly used methods. Hindered phenolic antioxidants are favored for their cost-effectiveness, but small molecule antioxidants like tert-butylhydroquinone (TBHQ) and butylated hydroxytoluene (BHT) suffer from sublimation at high temperatures, resulting in poor oxidation resistance. Conversely, commercial macromolecular antioxidants, such as L-1010 and L-1076, fall short of the antioxidant needs of hydrocarbon fuels due to their limited properties.In order to make up for the shortage of commercial hindered phenolic antioxidants, researchers have focused on the development of new antioxidants with high temperature resistance and significant antioxidant effect. Calixarenes, with their structural features of hindered phenols, are seen as potential antioxidants, Especially, the calixarene synthesized with resorcinol as monomer has high phenolic hydroxyl content, which can quench the oxygen free radicals produced in the process of fuel oxidation by providing more abundant hydrogen free radicals, thus has better oxidation resistance.However, reports on using calixarenes for enhancing the oxidation resistance of high-density hydrocarbon fuels remain scarce.In this paper, C-undecylcalix[4]resorcinarene(C11-C[4]R) was synthesized by using resorcinol and dodecanal, and its oxidation resistance in high-density hydrocarbon fuel JP-10 was investigated.and compared with several commercial antioxidants:2,6-di-tert-butyl-4-methylphenol, tetra [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester. The results of high pressure differential scanning calorimeter (PDSC) showed that the effect of four antioxidants ranked as follows: C11-C[4]R > BHT > L-1010 > L-1076. In addition, the oxidation consumption process of four hindered phenolic antioxidants in JP-10 was analyzed from the perspective of kinetics, and the oxidation consumption rate constant was calculated. The results showed that the reaction rate constant of C11-C [ 4 ] was the smallest and the consumption rate in JP-10 was the slowest. Besides, the oxidation reaction process of JP-10 was also studied using the static kettle accelerated oxidation method. Based on these findings, a potential antioxidant mechanism of C11-C[4]R in JP-10 was proposed.
A research paper
Surface reaction and lattice oxygen transfer in chemical looping oxidative coupling of methane: molecular dynamics simulations
LI Wanying, CHEN Liangyong
 doi: 10.1016/S1872-5813(23)60412-8
Abstract(27) HTML(6) PDF 1910KB(4)
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Chemical looping oxidative coupling of methane (CL−OCM) is a promising methodology for ethylene production from methane. This article utilizes molecular dynamic (MD) simulation to assess the performance of eight metal oxide catalytic oxygen carriers in CL−OCM reactions It also investigates the impact of reaction time and particle size on the efficiency of the most effective Mn2O3 COC. The results indicate that extending the reaction time appropriately enhances C2H4 selectivity and a C/O ratio of 1 is found to be the optimal size for Mn2O3-based CL−OCM. Furthermore, surface reactions and lattice oxygen transfer are analyzed by MD simulation in Mn2O3-based CL−OCM, providing deeply insights into the reaction mechanism. The findings reveal that the gas-phase dimerization of CH3 * to form C2H6 serves as the primary carbon coupling pathway in CL−OCM. In addition, there are two other carbon coupling pathways, both initiated by CH2 *. Methanol formation through surface combination of CH3 * and OH* represents an initial step in CL−OCM side reactions. Therefore, inhibiting methanol formation is crucial for enhancing C2 selectivity in CL−OCM. There exists a transformation of lattice oxygen and surface lattice oxygen plays a key role in methane activation. The quantity of lattice oxygen and difference in bulk lattice oxygen migration resistance are major factors influencing variations CH4 conversion and C2 selectivity. This study provides a new way to reaction mechanism exploration related to CL−OCM catalytic oxygen carriers.
review
The research progress of formation and control on the N-containing compound of biomass pyrolysis gas
WANG Fengchao, ZHU Hongyu, YIN Xiuli, XU Bin, LI Weizhen, LIU Huacai
 doi: 10.19906/j.cnki.JFCT.2023090
Abstract(12) HTML(5) PDF 11007KB(3)
Abstract:
Biomass energy plays an important role in combating global warming and the depletion of fossil energy sources. Although different recovery technologies of biomass energy were utilized industrially, the development level of different recovery technologies varies. The application of biomass energy includes technologies such as combustion, pyrolysis, gasification, and fermentation. The pyrolysis technology is an efficient and economical method to utilize biomass energy, which combines the advantage of energy recovery and product diversification. However, the N-containing compounds in the biomass pyrolysis gas make the pyrolysis gas of low quality, which combustion leads to secondary pollution of air. This review summaries the research status of N-containing compounds in the biomass pyrolysis gas, mainly reviewing the differences in the thermos-gravimetric behavior of typical biomass and the four compositions in biomass (cellulose, hemicellulose, lignin, and proteins). There were significant differences in the thermos-gravimetric behavior of biomass with different material compositions, but the whole TG curve can be divided into three stages: in the first stage, the pyrolysis of easily decomposable components in biomass releases small molecule gases and steam; In the second stage, the pyrolysis of cellulose, hemicellulose, and lignin in biomass released a large amount of O-containing bio-oil; in the third stage, the volatile components attached to the surface of the bio-char were cracked again and condensation reaction occurs. The nitrogen content in biomass was high, and during the pyrolysis process, nitrogen migrated into the solid-liquid-gas three-phase, and the migration transformation process was extremely complex. This review also discussed the generation mechanism of N-containing compounds in biomass pyrolysis gas and analyzed the distribution and control research of N-containing compounds. The NH3 in the low-temperature pyrolysis gas was mainly derived from the direct pyrolysis of protein in biomass. With the increase of pyrolysis temperature, the biomass pyrolysis volatiles were cracked secondly to generate N-containing heterocyclic substances, nitriles, and cyclic amides, and further cracked to produce HCN. Under the high-temperature atmosphere, partial HCN reacts with ·H and generates NH3 with the biomass char catalysis, leading to a decrease in the concentration of HCN. The N-containing heterocyclic substances from the second cracking of volatiles were the main resource of HCNO, and HCNO has a relatively lower concentration and is easily reduced to HCN and NO. Thus, with the pyrolysis temperature increase, the main components of N-containing compounds in the pyrolysis gas were gradually converted from NH3 and HCNO to NO and HCN. When the temperature was 800 ℃, the concentration of NO accounted for 40% of the N-containing compounds in pyrolysis gas. While, at 900 ℃, NH3 and HNCO were barely detectable. At the same time, it pointed out the difficulties and challenges faced in the practical application of N-containing compound removal. It is necessary to establish a generalized mechanism for nitrogen conversion during the thermal conversion of biomass. The nitrogen transport and control mechanisms during biomass pyrolysis need to be further improved. And, the key research directions in the process optimization and economic analysis of N-containing control are further anticipated. This review aims to provide a theoretical basis and technology support for biomass pyrolysis gas purification.
Study on the catalytic performance of CO-PROX catalyzed by CuO-NiO/CeO2 in H2/CO2 rich atmosphere
CAO Dongliang, LIU Shu, JIANG Yaxin, HAN Jiao, ZHANG Caishun, WANG Honghao, HOU Xiaoning, ZHANG Lei, GAO Zhixian
 doi: 10.19906/j.cnki.JFCT.2023077
Abstract(50) HTML(37) PDF 1562KB(7)
Abstract:
The CuO-NiO/CeO2 catalyst was prepared by step impregnation method. The catalyst was characterized by XRD, BET, H2-TPR, Raman and XPS, and the effects of the calcination temperature of NiO-CeO2 precursor on the physicochemical properties of the catalyst and the selective oxidation of CO in H2/CO2 rich atmosphere were investigated. The results showed that the precursor calcination temperature mainly affected the reduction performance and oxygen vacancy content of the catalyst. When the calcination temperature is 500 ℃, the content of oxygen vacancy in the catalyst is higher, and the catalytic performance is better. When the reaction temperature is 130 ℃, the oxygen excess coefficient is 1.2, and the air speed is 20266 mL/(g·h), the CO conversion rate is 95.9%, and the CO oxidation selectivity is 86.3%.
Preparation and properties of MnCu/Ce catalyst for CO preferential oxidation reaction
WU Jiaxin, HAN Jiao, LI Xue, XING Yue, ZHANG Caishun, LIU Daosheng, HOU Xiaoning, LIU Yajie, ZHANG Lei, GAO Zhixian
 doi: 10.19906/j.cnki.JFCT.2023080
Abstract(48) HTML(30) PDF 2145KB(11)
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The MnCu/Ce catalyst with a lower Cu content was prepared by co-impregnation method, and then was characterized by XRD, BET, H2-TPR, XPS and CO2-TPD. The effects of calcination temperature on the structure and properties of the catalyst and the preferential oxidation of CO in a hydrogen-rich atmosphere containing CO2 were investigated. The results indicated that Cu/Mn-O-Ce solid solution was formed in all MnCu/Ce catalysts. Of theses sample, the one calcined at 600 ℃ had strong interaction among Mn, Cu and Ce, formed more ternary oxide solid solution with more oxygen vacancies/Ce3+, and revealed good CO-Prox activity. In addition, it was found that the addition of different percentage of Ar had little effects on the CO-Prox activity of the catalyst, while the space velocity and oxygen excess coefficient had great effects on the catalytic performance, and the presence of CO2 in the reaction feedstock gas had a negative effect on the CO-Prox reaction. At an oxygen excess coefficient of 1.2 and the space velocity of 20266−30400 mL/(g·h), the highest CO conversion rate reached 94.7%.
TG-FTIR study on escape behavior of products from co-pyrolysis of residuum and coal
ZHOU Xiaodong, WU Hao, LIU Jingmei, HUANG Xueli, LIU Ting, ZHONG Mei, MA Fengyun
 doi: 10.1016/S1872-5813(23)60393-7
Abstract(41) HTML(12) PDF 2205KB(3)
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Coal and heavy oil are first co-pyrolyzed, and then hydrogenated into small molecule products during co-liquefaction. Therefore, clarifying influence of heavy oil on coal pyrolysis performance is an important thermochemical basis for regulating the process. The co-pyrolysis behavior of atmospheric residue (AR) and Naomaohu coal (NMH) were investigated by TG, TG-FTIR and distributed activation energy model. The results showed that the peak temperature of the maximum rate of weight loss for the co-pyrolysis process was reduced by 7 °C compared with the theoretical value calculated by weighted average of AR and NMH pyrolysis alone, while the weight loss increased by 3%, the average activation energy decreased by 23.6 kJ/mol. In addition, the peak area of alkyl O-containing functional groups such as alcohols and ethers increased, whereas those of CO and CO2 decreased, suggesting that AR had a positive effect on NMH pyrolysis. Meanwhile, alkyl radicals from AR decomposition would combine with O-containing radicals generated from coal pyrolysis, thus resulting in a decrease of CO and CO2 by inhibiting breakage of carboxyl groups. This work will provide a scientific evaluation basis for revealing the influence of heavy oil on composition of coal liquefaction product during co-liquefaction.
Research progress in catalysts for producing higher alcohols from bioethanol
WANG Wenwen, LU Yangyang, LI Zhiyu, ZHANG Yuchun, FU Peng
 doi: 10.19906/j.cnki.JFCT.2023061
Abstract(131) HTML(58) PDF 21094KB(10)
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Compared with ethanol, higher alcohols have the advantages of high Cetane number, high energy density, non corrosiveness to engine parts, immiscibility with water, good stability, and other advantages as fuel or fuel additive directly. The conversion of fermentation bioethanol into more valuable higher alcohols has attracted widespread attention. This paper reviewed the research progress of bioethanol to higher alcohols at home and abroad in recent years, including the research and development of metal oxides, hydroxyapatite (HAP) and supported metal catalysts, Finally, the current challenges and future research trends of bioethanol to higher alcohols are summarized and prospected, pointing out that the development of multifunctional catalysts is the focus of future research, and Aldol condensation is an effective strategy to further improve the conversion and selectivity of bioethanol to higher alcohols.
Progress in design and application research of nitrogen carrier in chemical looping ammonia synthesis technology
GONG Zhouting, ZHANG Tan, LI Na, YANG Yanyan, LIU Shoujun, ZHENG Jie, YU Zhongliang, YANG Song
 doi: 10.1016/S1872-5813(23)60397-4
Abstract(99) HTML(95) PDF 2840KB(31)
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Ammonia is not only the main raw material of nitrogen fertilizer production, but also one of the energy carriers for the storage and conversion process of renewable energy. Therefore, the development of a mild ammonia synthesis technology has become an important research topic in recent years. The chemical looping ammonia synthesis technology decouples the ammonia synthesis reaction into several steps, including the nitrogen fixation and the ammonia release, which has the advantages of easy operation, mild reaction, and low energy consumption. As the key to the chemical looping ammonia synthesis, nitrogen carriers play the role of transferring energy and nitrogen species. However, the current low nitrogen fixation efficiency of nitrogen carriers severely limits the development of the chemical looping ammonia synthesis technology. Therefore, this article reviews the research on the design, preparation and application of nitrogen carriers for the chemical looping ammonia synthesis. Firstly, the design theory of nitrogen carrier is summarized; secondly, the current research status of nitrogen carrier is introduced, with a focus on how to improve the ammonia production rate of nitrogen carrier and the utilization rate of lattice nitrogen; finally, the opportunities and challenges of chemical looping ammonia synthesis technology are discussed, which provide a reference for the design and development of nitrogen carrier in the future.
Research progress on CO2 catalytic conversion to value-added oxygenates
LI Yongheng, WU Chongchong, WANG Wenbo, XIN Jing, MI Xiaotong, YANG Guoming, SU Mengjun, ZHANG Siran, LI Hongbao
 doi: 10.1016/S1872-5813(23)60404-9
Abstract(74) HTML(60) PDF 34846KB(25)
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Chemical conversion of greenhouse gas CO2 into value-added oxygenates such as ethanol, acetic acid, propanal, propionic acid, butanol, etc. is challenging due to the complexity of C-C coupling and the uncontrollable bonding. In this review, recent research progresses on the synthesis of multi-carbon oxygenates from CO2 in fixed bed reactor are provided. Firstly, the reaction mechanisms of CO2 hydrogenation are summarized. Then, the potential catalysts applied in one-step or tandem CO2 hydrogenation, dry reforming with light hydrocarbons and hydroformylation were introduced over metal carbides, alkali metal modified single or binary metal catalysts such as Cu, Fe, Co, Rh, etc. The reaction mechanism over different catalysts were further elaborated. Finally, the problems and and outlook are discussed.
Review on the progress in the production of aromatic hydrocarbons by co-catalytic pyrolysis of biomass and plastics
HAN Dong, SUN Laizhi, CHEN Lei, YANG Shuangxia, LI Tianjin, XIE Xinping, XU Meirong, TANG Wendong, ZHAO Baofeng, SI Hongyu, HUA Dongliang
 doi: 10.1016/S1872-5813(23)60401-3
Abstract(121) HTML(12) PDF 8991KB(44)
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Aromatic hydrocarbons, especially monocyclic aromatic hydrocarbons such as benzene, toluene, and xylene (BTX), are important basic raw materials in the chemical industry, which are mainly derived from the catalytic reforming and thermal cracking of fossil fuels. The co-catalytic pyrolysis of biomass and plastic to produce aromatics has the advantages of high efficiency, environmental protection, low cost, and high selectivity. It can solve the problems of pyrolysis products such as high oxygen content, low aromatics yield, and low selectivity, which are caused by the characteristics of biomass rich in oxygen and poor in hydrogen. This article reviewed the research progress of co-catalytic pyrolysis of biomass and plastics to prepare aromatic compounds. Firstly, the types of raw materials for co-catalytic pyrolysis were introduced, and then the co-catalytic pyrolysis catalysts were emphasized. The reaction mechanisms of co-catalytic pyrolysis of biomass and plastics, such as the synthesis of dienes and hydrocarbon pool synergy were summarized. Finally, the future research focus and development direction of co-catalytic pyrolysis of biomass and plastics were proposed, which is developing the highly active and stable modified molecular sieve catalysts in order to improve the aromatics yield.
A research paper
Multi-site Co2P Catalyst Derived from Soybean biomass for Dehydrogenation of Formic Acid
WANG Bixi, LIU Zeyu, WU Yabei, YANG Yanyan, YANG Song, WANG Xun, YE Zi, DONG Hongliang, ZHU Feng, YU Huanhuan, LÜ Yingying, YU Zhongliang
 doi: 10.1016/S1872-5813(23)60410-4
Abstract(7) HTML(6) PDF 4248KB(0)
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Formic acid (FA) is a sustainable liquid organic hydrogen carrier and the catalyst for hydrogen production from FA has received significant attention. However, the development of efficient non-noble metal catalysts still remains challenges. In this work, we provide a technologically rather simple and environmental-friendly strategy to synthesize Co2P catalyst for dehydrogenation of FA by pyrolyzing soybean powder and cobalt salt. The K-containing solid bases in catalyst could act as Lewis acid sites for the HCOO intermediate adsorption while the self-doped N could act as Lewis base sites to enhance the H+ adsorption. The P contained in soybean could combine with Co to form Co2P for H−C bond cleavage of HCOO. At a Co(NO3)2·6H2O/soybean mass ratio of 1∶15, the as prepared Co2P catalyst demonstrated a gas production rate of 237.47 mL/g/h and a good stability. This study provides a novel strategy to develop non-noble metal heterogeneous catalysts for FA dehydrogenation.
A research paper
Study on copper-based oxygen carrier catalytic power plant flue gas deoxidation
SIMA Hao, WANG Xuefeng, DENG Cunbao
 doi: 10.1016/S1872-5813(23)60409-8
Abstract(11) HTML(8) PDF 8838KB(6)
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The main components of power plant flue gas are N2, CO2 and part O2. Injecting power plant flue gas into mine goaf can achieve CO2 storage and replace nitrogen injection to prevent spontaneous combustion of left coal. However, O2 in flue gas is one of the factors causing spontaneous combustion of left coal. Therefore, it is urgent to develop an economical and effective catalyst to remove O2 from power plant flue gas. In this study, four types of copper-based catalysts were prepared using a controllable modulating carrier and loading capacity through co-precipitation method. Additionally, a series of xCuO/CeO2 catalystswere synthesized. The catalysts were characterized using BET analysis, XRD analysis, ICP analysis, TEM analysis, H2-TPR and XPS analysis to establish a structure-activity relationship between catalyst structure and deoxidation performance for catalytic power plant flue gases. The results showed that the addition of CeO2 improved the dispersion of CuO, increased the oxygen vacancy of the catalyst, and improved the activity and reduction oxidation performance of the catalyst. Moreover, the synergistic effect of Cu-Ce interface structure promoted the reduction oxidation process, showing good activity and cycle stability. Among xCuO/CeO2 catalysts, 30CuO/CeO2 showed the best catalytic deoxidation performance due to its smallest CuO particle size, highest dispersion and highest oxygen vacancy concentration. The results of this study provide a reference for the development of low cost, recyclable, high activity and high stability deoxidation catalysts.
A research paper
Effect of zinc content on the structure of Zn species and catalytic properties over Zn/ZSM-5
GENG Rui, LIU Yacong, NIU Xianjun, DONG Mei, FAN Weibin, QIN Zhangfeng, WANG Jianguo
 doi: 10.19906/j.cnki.JFCT.2023089
Abstract(32) HTML(0) PDF 1909KB(5)
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Studying the status and distribution of Zn species on Zn/ZSM-5 zeolite catalysts were of great significance for determining the active centers and establishing structure-activity relationships in the ethylene aromatization process. The effect of zinc contents of Zn/ZSM-5 zeolites prepared by incipient-wetness impregnation method on catalytic performances in ethylene aromatization were investigated. The structures and acidic properties of the catalyst were studied through X-ray powder diffraction (XRD), N2 adsorption/desorption, and infrared spectra for pyridine adsorption (Py-IR). Besides, inductively coupled plasma-atomic emission spectrum (ICP), diffuse reflectance ultraviolet-visible spectrum (UV-vis DRS), extended X-ray absorption fine structure (EXAFS) and linear combination fitting (LCF) analysis on X-ray Absorption near edge spectra (XANES) had finely analyzed the structure and transition of Zn species and the losing rate of Zn species on HZSM-5 molecular sieve catalyst during ethylene aromatization process. The results showed that the introduction of Zn was advantage to improve the selectivity of aromatics hydrocarbon, and Zn contents of the catalyst had obvious influence on the structures, acidic properties, and the status of Zn species, as well as the catalytic performance of Zn/ZSM-5 catalysts. At low zinc loading, 1.5%-Zn(IM)/Z5 catalyst with more active 6-fold coordinated ZnOH+ species (55%) showed the highest selectivity to aromatics and catalyst stability. With the increase of zinc amount, the excessive Zn contents not only covered the acid sites and blocked the pore channel, but also changed the local coordination structure and state of Zn species. It was confirmed that the oxidizability of Zn species and the coordination number around Zn sites decreased, accompanied by a weakening of the interaction between Zn and zeolite, leading to the formation of large amounts of 4-fold coordinated ZnO clusters and ZnO crystallites. In the 4%-Zn(IM)/Z5 catalyst, Zn species composed of multi characteristics from ZnOH+, ZnO clusters inside the pores, and ZnO crystals on the external surface with relative contributions of 23.5%, 56.1%, and 20.4%, respectively. It meant that ZnO clusters and ZnO crystallites became the main component at the high Zn content. Furthermore, ZnO species located on the outer surface of Zn/ZSM-5 catalysts were easily reduced by H2 and then transported as zinc vapor to the outer surface, which eventually lead to the loss of Zn species from the catalyst and the decline of the catalytic performance of Zn/ZSM-5 catalyst. The relative proportion of ZnOH+ decreased with that of ZnO clusters and ZnO crystallites correspondingly increased considerably with the increase of Zn loading on ZSM-5, accompanied with the elevated rate for Zn losing, and shortened catalyst life. Therefore, a positively correlated between the content of ZnOH+ obtained through the UV-vis DRS and LCF analysis on XANES and the rate of aromatics formation was established, further confirming the catalytic nature of ZnOH+ as the active center, which played an important role in the aromatization reaction that enhancing the formation of aromatic hydrocarbons. Meanwhile, ZnO on the outer surface of Zn/ZSM-5 catalysts was the main species that losing from catalyst, and influenced the catalytic properties on a certain degree.
A research paper
Mechanism of catalytic decomposition of NO by Cu-ZSM-5
ZHANG Huan, LIU Liang, SHI Yilin, QIAO Xiaolei, JIN Yan
 doi: 10.1016/S1872-5813(23)60408-6
Abstract(6) HTML(4) PDF 5388KB(2)
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Catalytic decomposition of NO by Cu-ZSM-5 has potential application. In order to reveal the catalytic decomposition mechanism of NO over Cu-ZSM-5, the adsorption of NO over short-range Cu+ pairs in Cu-ZSM-5 was simulated based on the density functional theory, and proposed reaction pathways for the catalytic decomposition of NO assisted by by-products N2O and NO2. The calculation results show that the double nuclear copper-oxygen species is an important active center of Cu-based catalyst. During the catalytic decomposition of NO, the highest activation energy (171.39 kJ/mol) was required for the decomposition of the by-product NO2 on the double nuclear copper-oxygen species, and an activation energy base of 86.92 kJ/mol was required for the decomposition of N2O, suggesting that the decomposition of NO2 in the active site is more difficult than the decomposition of N2O. The resolution of N2 and O2 absorbed 28.43 and 100.78 kJ/mol of energy, respectively. And the rate determining step was O2 desorption. NO acts both as a reactant and a key reductant for the redox cycle achieved in the active center of Cu-ZSM-5 during the catalytic process.
A research paper
Mechanism of heterogeneous reduction of NO by graphite-supported single-atom Fe catalyst: DFT study
ZHAO Yan, LI Xiang, HUANG Jinkai, LI Xianchun, ZHU Yaming, WANG Huanran
 doi: 10.1016/S1872-5813(23)60407-4
Abstract(22) HTML(15) PDF 5095KB(5)
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The micro-mechanism of NO heterogeneous reduction by graphite carbon supported single atom iron catalyst (Fe/G) was studied using density functional theory (DFT), transition state theory (TST), and the reason of catalyst deactivation was analyzed. The results showed that the NO reduction reaction based on E-R mechanism undergoes four stages of N2O formation and release, N2 formation and release. However, the NO reduction reaction based on L-H mechanism undergoes two stages of N2 formation and release. Based on the E-R mechanism, the energy barrier of NO reduction rate-controlled step in which NO molecule is adsorbed on Fe atom with N,O-down structure is only 15.5 kJ/mol, which is lower than that of other paths. Through energy barrier analysis, the energy barrier value of reactive oxygen species reduced was higher than that formation of N2. Reactive oxygen species remaining on the surface of Fe atom after NO decomposition inhibited the adsorption and reduction of NO, and the absence of active site leads to the deactivation of catalyst. The presence of single-atom Fe promoted the NO reduction reaction. Through kinetic analysis, with the increase of reaction temperature, the NO reduction rate increases more significantly than the reactive oxygen transfer rate.
Highly effective MFe2O4 (M=Zn, Mg, Cu and Mn) spinel catalysts for Fischer-Tropsch synthesis
WANG Chao, CHEN Jiangang, ZHU Huaqing, ZHANG Wenshao, BAI Hongbin, ZHANG Juan
 doi: 10.1016/S1872-5813(23)60406-2
Abstract(43) HTML(13) PDF 4775KB(18)
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A series of spinel catalysts, including ZnFe2O4, MgFe2O4, CuFe2O4, and MnFe2O4, were prepared and applied to the Fischer-Tropsch synthesis (FTs). Zn, Mg, Cu and Mn easily form spinels with Fe. Among them, Zn and Mg can significantly maintain the spinel structure during the pretreatment and reaction, resulting in a low CO conversion. Cu and Mn are beneficial to the formation of iron carbide during the reaction, resulting in an apparent influence on FTs performance. ZnFe2O4 has little effect on the hydrocarbon distribution and the olefin/paraffin (O/P) ratio of C2−C4. MgFe2O4 exhibits low selectivity for C5+ hydrocarbons, and the selectivity of $ {\mathrm{C}}_2^=-{\mathrm{C}}_4^=\;$ and the O/P ratio of C2−C4 in the product are increased due to the alkaline effect of Mg. Cu can promote the carbonization of the catalyst, so that CuFe2O4 has higher activity.Meanwhile, CuFe2O4 can significantly improve the selectivity of C5+ hydrocarbons. Moreover, Cu can promote the dissociation and activation of H2, which is beneficial to the secondary hydrogenation of olefins, thereby reducing the selectivity of $ {\mathrm{C}}_2^=-{\mathrm{C}}_4^=\;$ and the O/P ratio of C2−C4. Mn promotes carbonization during the reaction, but MnFe2O4 has little effect on the chain growth of hydrocarbon. However, Mn can promote the generation of a certain amount of ε-Fe2C, which may explain the higher selectivity of $ {\mathrm{C}}_2^=-{\mathrm{C}}_4^=\;$ and the O/P ratio of C2−C4 for MnFe2O4. All spinel catalysts exhibit low CO2 selectivity, which meets the current green environmental protection requirements.
A research paper
Hydrothermal Flowthrough Pretreatment of Biomass and Pyrolysis Characteristics of Its Residual Solid
LIU Tianlong, LI Qi, LI Zhonghong, YANG Peiyan, PANG Xinbo, HUANG Xin, ZHAO Xiaoyan, Cao Jingpei1
 doi: 10.19906/j.cnki.JFCT.2023082
Abstract(28) HTML(12) PDF 4322KB(12)
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The sophisticated multi-components and densed cross-link chemical structures of lignocellulosic biomass are important bottlenecks restricting its value-added utilization. The pre-fractionation of lignocellulose components is of great significance for the fractional conversion of biomass. The present study subjected rice husk (RH) to hydrothermal treatment in a flowthrough mode and investigated the effects of hydrothermal temperature and water flowrate on the decomposition rate of RH, chemical components of residual solids and their pyrolysis characteristics. It is shown that the decomposition of RH under hydrothermal conditions conformed well to the unreacted shrinking core model with phase boundary reactions rate-controlling. The pretreatment at 180 ℃ removed 95% alkali and alkaline-earth metallic species, 92% hemicellulose and 59% lignin from RH and selectively retained most of the cellulose components. As a result of the pretreatment, the relative content of anhydrosugar (mainly levoglucosan) from pyrolysis of RH at a curie-point temperature of 445 ℃ was increased from 9.9% up to 48.2% (area%) .
Dynamic behaviors and heat recovery with hot gas withdrawal of flow reversal reactor for thermal oxidation of lean methane
LI Zhikai, WU Zhiwei, QIN Zhangfeng, DONG Mei, FAN Weibin, WANG Jianguo
 doi: 10.1016/S1872-5813(23)60398-6
Abstract(46) HTML(12) PDF 1985KB(2)
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Lean methane from abandoned coal mines or drainage gas with methane concentration of 1%−3% is in general directly discharged into the atmosphere due to the lack of appropriate technology, which has caused serious environmental concerns due to its high global warming potential. While direct thermal oxidation of ultra-low methane in a flow reversal reactor offers an attractive solution, it poses challenges such as potential explosions and unstable combustion flames. Elucidating the dynamic behavior of thermal oxidation of ultra-low methane in a flow reversal reactor is the basis for practical application. To this end, autothermal operation boundary of a pilot-scale thermal flow reversal reactor was examined and the effects of hot gas withdrawal on the behavior of flow reversal reactor was deeply studied. It was found that autothermal operation can be achieved with a methane content of over 0.2% and heat can be recovered if methane content is over 0.5%. Withdrawal of hot air has a significant impact on the dynamic behavior of the reactor: maximum bed temperature at the pseudo-steady state without hot gas extraction keeps almost constant with methane concentration varying in 0.5%−3.0%; whereas for heat recovery by hot gas withdrawal, the maximum bed temperature increases with the increase of the amount of hot gas extracted, and the allowable hot gas exported from the reactor increases nearly linearly from 12.5% to 32% as the methane content increases from 0.5% to 3.0%. Furthermore, the appropriate switching time decreases with the increase of the amount of hot gas withdrawn; for most cases, reversing flow direction at a time interval of 30−50 s can ensure complete methane conversion and stable bed temperature. Thus, it may be concluded that lean methane (1%−3%) can be mitigated by thermal oxidation without worrying about the bed temperature runaway or explosion.
Investigation on production of dimethyl carbonate from propylene carbonate and methanol on calcium cerium-based catalysts
GUO Jiong, YANG Jinhai, SHI Yilin, ZHAO Ning, XIAO Fukui, JIANG Xindong
 doi: 10.1016/S1872-5813(23)60394-9
Abstract(55) HTML(6) PDF 2282KB(8)
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Calcium cerium-based catalysts with different Ca:Ce molar ratio prepared by sol-gel method were characterized by XRD, N2 adsorption-desorption, FT-IR, XPS and CO2-TPD, and evaluated the activity for dimethyl carbonate (DMC) synthesis from propylene carbonate (PC) and methanol. The results indicated that more surface oxygen vacancies and more moderate basic sites are beneficial for methanol activation and thus leading to better catalytic activity. The PC conversion was 91.12% with DMC selectivity of 91.72% over 0.9CaCe under the reaction conditions-reaction time of 2 h, reaction temperature of 40 °C, methanol to propylene carbonate molar ratio of 15:1 and catalyst amount of 4% relative to the amount of PC.
Enhanced photocatalysis using metal-organic framework MIL-101(Fe) for crude oil degradation in oil-polluted water
LIANG Yuning, WANG Baohui, LI Shuohui, CHI Weimeng, BI Mingchun, LIU Yuxuan, WANG Yiran, YAO Ming, ZHANG Tianying, CHEN Ying
 doi: 10.1016/S1872-5813(23)60396-2
Abstract(51) HTML(3) PDF 3687KB(9)
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A stable metal-organic framework (MOF), MIL-101(Fe), was successfully synthesised using a solvothermal method and employed as a novel photocatalyst for degrading crude oil in oilfield wastewater. Through optimisation of reaction conditions, the following optimal parameters were determined: a dark reaction time of 30 min, a light reaction time of 30 min, a pH of 5.5, a catalyst amount of 0.15 g/L, and a reaction temperature of 303.15 K. Under these reaction conditions, an impressive removal of 94.73% was achieved. This study represents the first application of Fe-based MOFs in the photocatalytic degradation of oilfield wastewater. MIL-101(Fe) notably demonstrated excellent stability under mild acid conditions and can be efficiently recycled. These findings offer valuable insights into using MIL-101(Fe) as a promising material for industrial applications in removing crude oil from oil-polluted water through photocatalytic degradation.
CH4 partial oxidation mechanism of LaFeO3 oxygen carrier in chemical looping reforming
WANG Nana, FENG Yuchuan, GUO Xin, MA Suxia
 doi: 10.19906/j.cnki.JFCT.2023075
Abstract(63) HTML(14) PDF 2642KB(20)
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Density functional theory (DFT) calculations were employed to reveal the CH4 partial oxidation mechanism of LaFeO3 oxygen carrier during chemical looping reforming. The CH4 partial oxidation reaction network was constructed by systematically studying the elementary reaction steps, including CH4 adsorption activation, H2 and CO formation, and oxygen diffusion. It was found that CH4 undergoes a gradual dehydrogenation reaction to form H atoms, and the energy barrier (1.50 eV) of CH3 dehydrogenation is the highest, which is the rate-limiting step. There are two possible paths for H2 formation on the surface of oxygen carrier. It is the main route that the H atom from O-top site to Fe-top site bonds with another H atom on O-top site to form H2 molecule. Due to its relatively low energy barrier (1.27 eV), the CO formation process is easier to occur. Oxygen diffusion needs to overcome an energy barrier of 1.35 eV, indicating that it occurs at high temperatures and the diffusion rate is low. By comparing the energy barrier of each elementary reaction, it was found that the H2 formation is the rate-limiting step of CH4 partial oxidation kinetics for LaFeO3 oxygen carrier. The H migration is the key to limiting H2 formation, and accelerating the H migration is the main approach to improve the performance of LaFeO3 oxygen carrier. Based on DFT calculations, the H migration of A/B site doped LaFeO3 oxygen carriers could be studied, which is expected to achieve the rapid screening of potential A/B site effective dopants and guide the design and development of high-performance LaFeO3 oxygen carriers.
A DFT study on the formation mechanism of side product 1,2-propanediol in the hydrogenation of dimethyl oxalate over copper catalyst
LUN Guodong, YAN Weiqi, ZHOU Jinghong, ZHU Yi’an, LI Wei
 doi: 10.1016/S1872-5813(23)60399-8
Abstract(93) HTML(48) PDF 9762KB(9)
Abstract:
The costly separation of 1,2-propanediol (1,2-PDO), an unavoidable byproduct in the hydrogenation of dimethyl oxalate (DMO), significantly hampers the economic viability of coal-to-ethylene glycol (EG) technology. To address this challenge, the formation mechanism of the side product 1,2-PDO on the Cu(111) and Cu2O(111) surfaces during DMO hydrogenation was investigated, which focused on the active sites of copper catalyst and the dominant pathway through density functional theory calculation. The thermodynamics of each elementary step and the adsorption behavior of various species involved in the reaction network along with the local density of states and charge density difference were systematically analyzed. The results indicate that 1,2-PDO is generated more favorably on the Cu2O(111) surface than that on the Cu(111) surface, owing to the Lewis acid-base pairs, i.e. ${\rm{Cu}}_{{\rm{us}}}^{+} $ and ${\rm{O}}_{{\rm{suf}}}^- $ sites, present on the Cu2O(111) surface, which strengthens the binding of reactants, products, and reaction intermediates to the substrate. EG reacts primarily with methanol (MeOH) to form 1,2-PDO through Guerbet alcohol condensation reaction through three consecutive steps: alcohol dehydrogenation, aldol condensation, and unsaturated aldehyde hydrogenation. The ${\rm{O}}_{{\rm{suf}}}^- $ sites promote the dehydrogenation of alcohols into aldehydes, the generation of enolates during aldol condensation and the hydrogenation of unsaturated aldehydes, while the ${\rm{Cu}}_{{\rm{us}}}^{+} $ sites are responsible for the C–C coupling reaction. These findings may shed light on the mechanism of 1,2-PDO formation over Cu catalyst and provide fundamental knowledge for the development of more efficient catalysts and process optimization.
Research on the 9,10-dihyroanthrancene assisted catalytic pyrolysis of pine over nitrogen-doped activated carbon for preparation of alkoxyphenols
LI Wentao, ZHANG Chengbo, LI Kai, NIU Qi, LI Jihong, LU Qiang, JIA Bao, GAO Lijuan
 doi: 10.19906/j.cnki.JFCT.2023081
Abstract(23) HTML(9) PDF 4678KB(1)
Abstract:
In this study, nitrogen-doped activated carbon (NAC) was prepared from walnut shell and applied to the catalytic pyrolysis of pine for selective preparation of alkoxyphenols with 9,10-dihyroanthrancene (DHA) as the hydrogen donor. The effects of ammonia concentration on the physicochemical properties of NAC were investigated. The regulatory functions of DHA/pine ratio, pyrolysis temperature, and NAC/pine ratio on the generation of alkoxyphenols were revealed. The results showed that the pore structure and active sites distribution of NAC could be improved by proper ammonia concentration. The NAC prepared at ammonia concentration of 15% was the best for the production of alkoxylphenols. The yield of alkoxylphenols reached its maximum value of 5.27% at DHA/pine ratio of 3, pyrolysis temperature of 550 ℃, and NAC/pine mass ratio of 3, which was much higher than that from catalytic pyrolysis of pure pine (1.74%).
The effect of alkali and alkaline earth metals in biomass ash on the bio-oil components derived from biomass fast pyrolysis
DING Zixia, CAI Bo, CEN Kehui, CHEN Dengyu, MA Zhongqing
 doi: 10.19906/j.cnki.JFCT.2023076
Abstract(75) HTML(19) PDF 4109KB(13)
Abstract:
The alkali and alkaline earth metals (AAEMs) in biomass ash have a significant impact on the yield and component distribution of rapid plytic biooil. In this paper, corn straw is selected as the raw material. First, the effect of cascade deash removal pretreatment (distillation water, ammonium acetate and hydrochloric acid) on the selective removal of AAEMs and its biological oil components is studied, and then the effect of the type of AAEMs (K, Ca, Na and Mg), the concentration of chloride salt (0.5%, 2.5% and 5%), and the acid radical in metal salt(${\rm{SO}}_4^{2-} $, ${\rm{NO}}_3^- $, ${\rm{CO}}_3^{2-} $, ${\rm{HCO}}_3^- $, AC and ${\rm{PO}}_4^{3-} $)on the compound distribution of bio-oil was systematically investigated. The results show that in the process of ash removal pretreatment, with the deepening of the acidity of the ash removal solution, the removal rate of AAEMs gradually increases. According to the selective removal law of AAEMs in the process of cascade ash removal, their morphology in biomass can be divided into the following three groups, namely the water-soluble metal (K), the ion-exchanged metals (Ca and Mg), the acid-soluble metal (Na). The removal of AAEMs promoted the formation of levoglucosan (LG), while restrained the formation of ketones and furans. However, the incorporation of AAEMs in biomass presented an opposite variation trend. The AAEMs would act as catalyst during biomass pyrolysis which promoted the secondary cracking of LG, leading to the reduction of LG and increase of ketones and furans. In addition, different acid roots in potassium salt also have remarkable influence on the secondary cracking reaction of LG and the rupture of the aryl ether bond and the phenolic hydroxyl group in lignin. The influence of the acid roots on the secondary cracking reaction of LG was in the order of ${\rm{HCO}}_3^- $>${\rm{CO}}_3^{2-} $>AC>${\rm{PO}}_4^{3-} $>Cl>${\rm{NO}}_3^- $>${\rm{SO}}_4^{2-} $, while the influence of acid roots on the rupture of the aryl ether bond and the phenolic hydroxyl group was in the order of {\rm{CO}}_3^{2-}>Cl>${\rm{HCO}}_3^- $>${\rm{PO}}_4^{3-} $≈AC>${\rm{SO}}_4^{2-} $${\rm{NO}}_3^- $.
Experimental study on alkali lignin enhanced chemical looping gasification of pulverized coal char
GAO Xinglong, AN Fengxia, HU Yun, CHEN Guoqing, YI Qun, WU Xiaoyan, CAO Jinzeng, YAO Weishan, WEI Guoqiang
 doi: 10.19906/j.cnki.JFCT.2023078
Abstract(52) HTML(30) PDF 5411KB(10)
Abstract:
The pulverized coal char from the byproduct of China's coal coking industry has high yield and low activity, which is difficult to be directly recycled. The conventional thermochemical utilization method has harsh reaction conditions, catalyst deactivation and kinetic limitations. By using the alkali lignin from paper-making as a disposable catalyst, an alkali lignin enhanced chemical looping gasification method was constructed to treat coal coke powder, which can realize the collaborative resource utilization of industrial by-products. In this study, the reaction process of alkali lignin and coal char powder was studied by thermogravimetry and kinetic analysis. The thermal transformation experiment and kinetic analysis showed that alkali lignin could strengthen the chemical looping gasification process of pulverized coal char and promote the pyrolysis peak to move to low temperature. When the mass ratio of pulverized coal char to alkali lignin was 1∶3, the activation energy was 87.56% lower than that of coal coke powder alone, indicating that there was a synergistic effect between the two in the co pyrolysis process. The experiments in fixed bed reactor verified that the carbon conversion rate and the selectivity of syngas increased as the increasing of temperature and the content of alkali lignin and oxygen carrier, which effectively promoted the gasification reaction. However, excessive oxygen loading led to combustion reaction between syngas and lattice oxygen and reduce syngas selectivity. Under the optimal reaction conditions of 950 ℃, the mass ratio of coal char powder to alkali lignin is 1∶2, and the mass ratio of oxygen carrier to pulverized coal char/alkali lignin is 1∶1, the selectivity of syngas of alkali lignin/coal char powder in chemical looping gasification was 82.85%. This study provides a scientific basis for the resource utilization of alkali lignin and coal char powder.
2024, 52(3): 1-8.  
Abstract(22) HTML(5) PDF 41228KB(13)
Abstract:
Performance of Cu-Mn-Zn/ZrO2 catalysts for methanol synthesis from CO2 hydrogenation: The effect of Zn content
WANG Shiwei, YANG Jinhai, ZHOU Hongli, XIAO Fukui, ZHAO Ning
2024, 52(3): 293-304.   doi: 10.1016/S1872-5813(23)60391-3
Abstract(109) HTML(35) PDF 10873KB(51)
Abstract:
A series of Cu-Mn-Zn/ZrO2 catalysts with different Zn contents were prepared by sol-gel method and characterized by XRD, BET, TPR, N2O-adsorption, XPS, TPD and in-situ DRIFTS. It was found that by increasing a certain amount of Zn, the catalytic activity for CO2 hydrogenation increased. Among all samples, Cu3MnZn0.5Zr0.5 (CMZZ-0.5) possessed the best CO2 conversion (6.5%) and methanol selectivity (73.7%) at 250 °C and 5 MPa. Characterization results showed that Zn entered the Cu1.5Mn1.5O4 spinel structure, forming ZnOx and thus more surface OH groups. This increased the content of Cu0 and Cuα+, which improved the activation of H2 and CO2. The pathway of CO2 to methanol was also clarified through in-situ DRIFTS.
Lewis acid-base modulated lanthanum-doped zinc oxide catalyzed CO2 conversion to ethylene carbonate
DU Changyuan, SU Qian, XU Zhenyang, FU Mengqian, JIA Songyan, DONG Li
2024, 52(3): 305-312.   doi: 10.19906/j.cnki.JFCT.2023060
Abstract(95) HTML(42) PDF 4230KB(29)
Abstract:
The massive emission of the greenhouse gas CO2 has caused problems such as global warming and ecological damage. How to effectively utilize CO2 as a resource and create economic benefits has attracted much attention in recent years. In this paper, a series of La-doped ZnO catalysts were designed and synthesized targeting the synthesis of ethylene carbonate (EC) from CO2 and ethylene glycol (EG), which could modulate the Lewis acid-base sites on the ZnO surface, and the catalyst activity was investigated under additive-free conditions. La-ZnO-1%-550℃ had the best catalytic activity with 0.54% conversion of EG, 7.326 mmol/(h∙g) and 99% space-time yield and selectivity of EC at 130 ℃, 4 MPa CO2, and 1 h with good stability. Combined with the analysis of the crystal structure, morphology and surface acid-base of the catalysts, the results showed that La was uniformly distributed in the ZnO hollow nanosheets, and the surface of the La-doped ZnO calcined at 550 ℃ had the most Lewis acid-base sites, and the catalytic activity of the catalysts increased with the increase of moderate to strong Lewis acid-base sites.
Effect of Mg content in Ni/MgAl2O4 catalysts on catalytic performance during methane dry reforming reaction
LÜ Shuaishuai, XU Cheng, ZHANG Rongjun, LI Hongwei, LIU Yingshuo, WEN Fuli, HOU Chaopeng, SUN Xia, WANG Tianye, WU Yu, XU Run, XIA Guofu
2024, 52(3): 313-322.   doi: 10.19906/j.cnki.JFCT.2023058
Abstract(163) HTML(81) PDF 4041KB(42)
Abstract:
Methane dry reforming reaction is a promising route for the valorization of both CO2 and CH4. However, the catalysts usually suffered from the coking deactivation and the sintering of active phase under the harsh reaction conditions. In this paper, the Mg-Al spinel support with different Mg content prepared by the solvent evaporation-induced self-assembly method was investigated. With this support, Ni/MgAl2O4 was used as the catalyst for methane dry reforming to syngas. XRD, BET and TEM results showed that the addition of appropriate amount of magnesium (10%−15%) was beneficial to the formation of highly stable ordered mesoporous magnesia spinel support with large specific surface area, which can confine the Ni particles in the pore structure and thus enhance the nickel dispersion and improve the resistance of coke formation under high temperature. H2-TPR and XPS analysis indicated the addition of 10%−15% magnesium can promote the interaction between Ni and MgAl2O4, inhibiting the agglomeration of Ni and the coke formation with the active surface-adsorbed oxygen species. Detailed activity tests showed that Ni/MgAl2O4 catalysts with 10%−15% magnesium content has high CH4 and CO2 conversion. During the long-term test for 180 h, the Ni/15-MAO catalyst exihibited the CH4 and CO2 conversions of 92.6% and 92.5%, respectively. The coke deposition percentage was only 0.89% and the grain size of Ni was maintained after reaction.
Theoretical calculation study on the reaction mechanism of methanol/dimethyl ether carbonylation catalyzed by the B/Al/Ga-MOR zeolites
REN Pengyu, LIU Zhuo, QUAN Yanhong, GUO Junjun, MA Hong, WU Jianbing, WANG Yongzhao
2024, 52(3): 323-334.   doi: 10.1016/S1872-5813(23)60395-0
Abstract(83) HTML(16) PDF 3744KB(21)
Abstract:
The reaction mechanism of methanol/dimethyl ether (DME) carbonylation catalyzed by isomorphously substituted B-, Al-, and Ga-MOR zeolites (B/Al/Ga-MOR) was comparatively investigated by the density functional theory (DFT) calculations. The commonalities and differences between methanol and dimethyl ether as the reactant as well as among various MOR zeolites in the catalytic reaction pathways were disclosed, where one Si atom was substituted by B, Al or Ga at the 8-ring side pockets T3 sites or the 12-ring channels T4 sites of MOR. The results indicate that the insertion of CO into methoxy group to form acetyl groups follows the SN2 mechanism and is the rate-determining step in the carbonylation reactions. Under 473 K, either methanol or dimethyl ether is used as feedstock, the formed acetyl group prefers to interact with CH3O in methanol to form methyl acetate. The T3 sites show better carbonylation selectivity, whereas T4 sites display better trimethoxonium ions selectivity which favors the generation of aromatics and leads to the catalyst deactivation. Comparing with Al-MOR, the introduction of Ga and B at the T3 sites increases the free energy barriers of carbonylation, whereas the introduction of Ga and B in particular at the T4 sites can substantially increase the energy barriers of generating trimethyloxonium ions, which can effectively suppress the side reaction and improve the catalyst stability. This work contributes to the understanding of the catalytic roles of various acidic sites in different channels of the MOR zeolites and provides certain theoretical support for tailoring and designing efficient MOR zeolite catalysts for methanol/dimethyl ether carbonylation.
Reconstruction of copper nanoparticles catalysts and its catalytic performance for synthesis of dimethyl carbonate
PEI Yongli, QUAN Yanhong, REN Jun
2024, 52(3): 335-342.   doi: 10.19906/j.cnki.JFCT.2023086
Abstract(46) HTML(14) PDF 9986KB(19)
Abstract:
Dimethyl carbonate (DMC) is an important and environmentally friendly chemical intermediate to meet the growing demand for a clean and sustainable energy supply. Among several routes for DMC synthesis, the oxidative carbonylation of methanol has attracted much attention with the advantages of a high utilization rate of carbon source, moderate operating conditions and environmental benefits. More importantly, the oxidative carbonylation of methanol is an important development route of modern coal chemical industry in China, and the key lies in the design of highly efficient catalysts. Copper-based catalysts have been used extensively in this reaction. Problems, such as reactor corrosion and catalyst deactivation, occur with chlorine-containing catalysts. The development of chlorine-free catalysts is the focus of current research. Recently, Cu-based catalysts supported on carbon materials have been used extensively in DMC synthesis because of its high activity, high selectivity and facile preparation process. However, the carbon-supported Cu catalysts suffer from the leaching and aggregation of Cu nanoparticles (NPs) in the harsh reaction conditions of high temperature, high pressure as well as severe stirring, leading to the deactivation. It has become a key scienctific problem that needs to be addressed urgently. In our previous studies, several strategies have been attempted to solve the deactivation problem caused by these reasons. For instance, encapsulating Cu NPs with hollow porous carbon spheres or mesoporous carbon materials. Besides, the introduction of N species in the carbon framework or sulfonic acid groups and oxygen-containing groups on the surface of carbon materials leads to an anchoring effect on Cu NPs. Great progress has been made via these methods, yet still unsatisfactory. Supported metal clusters have adjacent metal sites, countable numbers of atoms in each clusters, and limited size range (normally smaller than 2 nm). Benefiting from these distinct geometric and electronic structures, supported metal clusters can trigger synergistic effects among every metal atom, and thus exhibiting enhanced catalytic activity and selectivity in catalysis. Besides, the strong metal-support interaction on supported metal clusters improve the stability of metal clusters, enhancing the catalytic stability. To prevent the aggregation of metal clusters, the metal loading of supported metal clusters catalysts are generally kept at a low level (≤1%). However, catalysts with insufficient numbers of active sites always lead to compromised mass-activity, which greatly restrict them from industrial applications. Hence, the synthesis of supported metal clusters with high metal loading and high stability is a great challenge. In this study, the Cu clusters catalysts with high Cu loading were synthesized via liquid phase reconstruction method under the condition of water and CO. The optimal 15Cu/NCNS-12-CO exhibited superb activity with STYDMC of 3520 mg/(g·h) and stability with the loss rate of 28% after 10 cycles. A series of characterization showed that the strongly reducing CO not only resulted in the partial reconstruction of copper nanoparticles (from ~9.7 nm to ~1.34 nm), but also effectively maintained the existence of Cu0 species, improving the catalytic activity and stability. Further investigation showed that the reconstruction of Cu nanoparticles was dependent on the interaction of atmosphere-metal-support, and was reversible under the oxidation and reducing atmosphere.
Study on preparation of cyclohexanol from lignin-derived phenolic compounds catalyzed by metal oxide-loaded ruthenium
ZHANG Wenhao, TONG Le, FENG Junfeng, PAN Hui
2024, 52(3): 343-352.   doi: 10.19906/j.cnki.JFCT.2023071
Abstract(103) HTML(44) PDF 6245KB(41)
Abstract:
Hydrodeoxygenation of lignin bio-oil to prepare liquid fuels is a very promising route. In this paper, a series of catalysts (Ru/CeO2, Ru/Nb2O5, Ru/ZrO2, Ru/Al2O3 and Ru/CeOx) supported on metal oxides were prepared by incipient wetness impregnation method, which were used to study the upgrading and hydrogenation of lignin-derived phenolic compounds phenol to cyclohexanol. By means of X-ray crystal diffraction (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), the structure and physical and chemical characteristics of the prepared catalyst were characterized. It was found that the oxygen vacancies contained in Ru/CeOx could adsorb the raw materials with oxygen groups well, which was beneficial to the efficient hydrogenation of phenol. At the same time, XPS showed that the effective active centers in Ru/CeOx, RuO2 and Ru0, were active sites for catalytic hydrogenation. Therefore, the combined action of oxygen vacancies and metal active sites made the catalyst have good hydrogenation activity. The effects of reaction temperature, pressure and time on hydrogenation were also investigated. It was found that the catalyst could completely convert phenol at a mild temperature (140 ℃) and the yield of cyclohexanol was 90.2%. The cycle characteristics of the catalyst were investigated, and it was found that the catalyst still showed excellent hydrogenation activity after being recycled for 4 times. At the same time, the intermediate products in the hydrogenation process were detected by GC-MS, and then the reaction path of phenol hydrogenation process was deduced.
Chemical looping hydrogen generation with multi-layer core-shell oxygen carrier of Fe@Al-Ti
CAI Zhiyang, ZHANG Junxian, WANG Xin, XIAO Huixia, GAO Yunfei, WANG Yifei
2024, 52(3): 353-361.   doi: 10.19906/j.cnki.JFCT.2023072
Abstract(75) HTML(30) PDF 7888KB(16)
Abstract:
Fe-Al-Ti oxygen carriers have good cycling stability and good properties of anti-carbon deposition in the chemical looping hydrogen generation (CLHG) process. However, the formation of FeAl2O4 reduces hydrogen yield and increases sintering. To weaken the formation of FeAl2O4 and to promote properties, the core-shell oxygen carriers of Fe@Al-Ti were prepared by self-assembly template combustion method, which took TiO2 as the inter-layer to separate Fe2O3 and Al2O3. The effect of multi-layer core-shell structure on reaction performance was evaluated on a fixed bed. The results indicated that the inter-layer of Fe@Al-Ti oxygen carriers effectively weakened the contact between Fe2O3 and Al2O3, thus reducing the formation of FeAl2O4 and improving properties of anti-sintering. The Fe@Al-Ti oxygen carriers significantly prevented carbon deposition and surface agglomeration, and had great cycling stability during the CLHG cycles. The core-shell oxygen carrier with a molar ratio of Al∶Ti=3.5∶1 got the highest carbon conversion rate and H2 yield, and oxygen storage capacity in a single cycle, with 57.4%, 75.0%, and 6.01 mmol/g, respectively, which were 28.4%, 30.0%, and 26.9% higher than those of non core-shell Fe-Al-Ti oxygen carriers.
Promotion of Cu/Ce supported red mud for NO removal from low and medium temperature flue gas
LI Yang, XU Bo, YANG He, JIN Lijun, HU Haoquan
2024, 52(3): 362-372.   doi: 10.1016/S1872-5813(23)60388-3
Abstract(90) HTML(37) PDF 2166KB(20)
Abstract:
Red mud is a solid waste in aluminum industry and has been proven to be an efficient alternative to NOx selective catalytic reduction (SCR) catalysts. Acid washing treatment to red mud can improve its alkalinity and surface properties, and increase the conversion rate of NOx. In this paper, Cu, Ce, and Cu/Ce was supported on acid washed red mud and NOx catalytic conversion performance on metal modified red mud catalysts was studied. The research results indicate that Cu+ and Cu2+ in the Cu supported catalyst effectively promote NO conversion rate of red mud in low-temperature (200−300 ℃) flue gas, reaching a maximum of 90.7%; Ce3+ and Ce4+ in Ce supported catalysts effectively promote the NO conversion rate of red mud in flue gas at 200–400 ℃, reaching a maximum of 94.0%; Cu/Ce supporting exhibits better NO conversion rate than single metal supported catalysts at low-temperatures, the optimal Cu∶Ce ratio for supporting is 1∶1; and also exhibits better NO conversion rate than Cu supported catalysts at high-temperature (300−400 ℃), reaching a maximum of 95.5%. The reason may be that under the synergistic effect of Cu/Ce, ACRM-Cu1Ce1 has stronger low-temperature redox ability, higher weak acidic peaks, higher average oxidation state of Fe ions, and higher Cu+ content.
C3H6-SCR denitration characteristics of CuCoCe-LDH catalysts
CHEN Jiayin, NING Shuying, FU Wei, CAI Chen, ZHOU Hao, SU Yaxin
2024, 52(3): 373-383.   doi: 10.19906/j.cnki.JFCT.2023073
Abstract(93) HTML(65) PDF 5356KB(27)
Abstract:
A series of Cu(x)Co(y)Ce(z)-LDH precursors were synthesized by one-step hydrothermal method, and Cu(x)Co(y)Ce(z)O mixed metal oxide catalysts were prepared after calcination and used to study the selective catalytic reduction of NO by C3H6 (C3H6-SCR) with a fixed bed micro-reactor. Due to the strong synergy between Cu, Co and Ce, Cu(0.21)Co(0.48)Ce(0.31)O achieves 95% NO conversion and 90% N2 selectivity at 225 ℃. In addition, ICP, XRD, TEM, XPS, H2-TPR were used to characterize the basic physical-chemical properties of the catalysts to investigate the relationship between physicochemical properties and catalytic reduction abilities. XRD results show that solid solutions are formed between Cu, Co and Ce, which promotes the dispersion of active metals. XPS and H2-TPR further demonstrate that redox reactions occur between Cu and Co, promoting the formation of oxygen vacancies, thereby improving their catalytic reduction capacity.
XRD characterization of structural evolution in low-middle rank coals
LI Xia, ZENG Fan-gui, WANG Wei, DONG Kui
2016, 44(7): 777-783.  
[Abstract](759) [FullText HTML](287) [PDF 2169KB](264)
摘要:
通过对28个最大镜质组反射率0.30%-2.05%镜煤样品的X射线衍射(XRD) 分析, 获得XRD结构参数, 得到这些参数随反射率增大呈现的阶段性规律。在镜质组反射率小于1.0%阶段, LaLc急剧增加, d002迅速减小, 含氧官能团的脱落和脂肪长度支链化程度减小占主导; 在1.0%-1.6%阶段, La持续增加, d002先增加后减小, Lc先减小然后趋于平稳, 芳香体系脱氢和调整空间位阻同时进行; 在1.6%-2.0%阶段, d002持续减小, LcLa的增大, 煤结构演化以芳构化为主。XRD结构参数演化与第一、二次煤化作用跃变关系密切。
Structural analysis of functional group and mechanism investigation of caking property of coking coal
LI Xiang, QIN Zhi-hong, BU Liang-hui, YANG Zhuang, SHEN Chen-yang
2016, 44(4): 385-393.  
[Abstract](464) [FullText HTML](413) [PDF 1138KB](45)
摘要:
以11种炼焦煤为研究对象,分别进行FT-IR和黏结指数G测试。采用PeakFit软件对FT-IR谱峰进行分峰拟合和定量计算,研究炼焦煤特征官能团含量与其黏结性间的关系。结果表明,煤黏结性大小与其FT-IR吸收峰密切相关,特别是3 000-2 800和3 700-3 000 cm-1两个吸收带;脂肪族结构是煤黏结性形成的主要决定因素,通常脂肪链越短或支链化程度越高,越有利于煤的黏结性形成;含-OH(或-NH)的氢键缔合结构可以与脂肪链协同作用,共同决定煤的黏结性能。不论煤分子有多大,只要是结构单元缩合度较小而作为桥键的脂肪链较多的结构形式,在热解过程中就会生成大量适度分子量、以结构单元为基元的液相物质。氢键是煤中主要的分子间作用形式,当若干形成氢键的官能团聚集缔合时,其相互作用会更强,甚至会形成类似超分子的结构;在形成胶质体阶段,这类氢键缔合的结构也会被打破,并形成以胶质体液相为主的物质。这些液相物质的存在,有利于胶质体的流动、黏连和固化成为半焦,从而最终获得优越的黏结性。
High resolution TEM image analysis of coals with different metamorphic degrees
LI Xia, ZENG Fan-gui, SI Jia-kang, WANG Wei, DONG Kui, CHENG Li-yuan
2016, 44(3): 279-286.  
[Abstract](428) [FullText HTML](337) [PDF 12189KB](34)
摘要:
利用高分辨率透射电子显微镜(HRTEM) 分析了三种不同变质程度煤样的结构特征.基于傅里叶-反傅里叶变换方法, 并结合Matlab、Arcgis和AutoCAD软件, 通过图像分析技术, 获得了HRTEM照片的晶格条纹参数.结果表明, 三种煤样的晶格条纹呈现不同特征, 按条纹长度分别归属于1×1-8×8共计八个类型.以3×3为临界点, 在1×1和2×2中, ML-8中芳香层片的比例高于DP-4和XM-3;在3×3-8×8中, ML-8中芳香层片的比例低于DP-4和XM-3.对比HRTEM和XRD参数d002发现, 随着镜质组反射率的增加d002都呈现递减趋势.
Effect of Na2O on mineral transformation of coal ash under high temperature gasification condition
CHEN Xiao-dong, KONG Ling-xue, BAI Jin, BAI Zong-qing, LI Wen
2016, 44(3): 263-272.  
[Abstract](407) [FullText HTML](320) [PDF 1275KB](29)
摘要:
利用XRD和FT-IR考察了高温弱还原气氛下Na2O对两种硅铝含量不同的煤灰中矿物质组成的影响, 揭示了Na2O影响煤灰熔融特性的本质.通过FactSage计算了高温下矿物质反应的ΔG, 探讨了Na2O影响煤灰中矿物质组成的机理.结果表明, Na2O对煤灰矿物质组成的影响与原煤灰的硅铝含量密切相关.硅铝总含量82.89%的煤灰, Na2O含量为5%-20%时, 钠长石和霞石的生成是煤灰熔融温度降低的主要原因; 当Na2O含量大于20%时, 导致煤灰熔融温度降低的原因是霞石的生成.硅铝总含量47.85%的煤灰, Na2O含量小于10%时, 没有含钠矿物质生成; 当Na2O含量大于10%时, 主要生成菱硅钙钠石、青金石和含钠的硅铝酸盐矿物, 导致煤灰熔融温度降低.FactSage计算表明生成含Na矿物质反应的ΔG较小, 其在高温下更容易发生.
Research progress in the direct conversion of syngas to lower olefins
YU Fei, LI Zheng-jia, AN Yun-lei, GAO Peng, ZHONG Liang-shu, SUN Yu-han
2016, 44(7): 801-814.  
[Abstract](1140) [FullText HTML](595) [PDF 8665KB](88)
摘要:
合成气直接催化转化制备低碳烯烃是C1化学与化工领域中一个极具挑战性的研究课题, 具有流程短、能耗低等优势, 已成为非石油路径生产烯烃的新途径。直接转化方式主要包括经由OX-ZEO双功能催化剂直接制低碳烯烃的双功能催化路线以及经由费托反应直接制备低碳烯烃的FTO路线。综述简述了近年来在合成气直接制备低碳烯烃方面的研究进展, 重点讨论了低碳烯烃的形成机理、新型催化剂的研发及助剂对其催化性能的影响, 并对合成气直接制烯烃的未来进行了展望。
Research progress on emission and control technologies of arsenic, selenium and lead in coal-fired power plants
HUANG Yong-da, HU Hong-yun, GONG Hong-yu, LIU Hui-min, FU Biao, LI Shuai, LUO Guang-qian, YAO Hong
2020, 48(11): 1281-1297.  
[Abstract](580) [FullText HTML](137) [PDF 8248KB](51)
摘要:
煤炭是中国重要的能源资源,而中国煤中重金属砷、硒、铅含量较高,燃煤电厂已经成为重要的砷、硒、铅排放源之一。针对电厂燃煤带来严峻的砷、硒、铅污染问题,本文首先介绍了燃煤释放的砷、硒、铅排放量大且危害性强,概述了世界各国关于重金属排放控制的相关政策法规,指出中国对燃煤重金属砷、硒、铅的排放控制势在必行;其次从煤中赋存形态、燃烧过程中的形态转化和质量分布三个方面阐释了燃煤过程中砷、硒、铅的迁移转化规律,重点描述了砷、硒、铅在颗粒物上的形态特征和尺度分布;最后综述了燃烧前、燃烧中和燃烧后对砷、硒、铅的排放控制技术,详述了吸附剂捕集和烟气净化装置协同脱除的研究进展,并论述了低低温除尘器和团聚技术对砷、硒、铅的强化脱除潜力。以期为燃煤电厂重金属砷、硒、铅超低排放的实现提供参考和指导。
Performance of Mn-Ce catalysts supported on different zeolites in the NH3-SCR of NOx
HUANG Zeng-bin, LI Cui-qing, WANG Zhen, XU Sheng-mei, FENG Ling-bo, WANG Hong, SONG Yong-ji, ZHANG Wei
2016, 44(11): 1388-1393.  
[Abstract](436) [FullText HTML](278) [PDF 780KB](29)
摘要:
分别以β、ZSM-5和USY分子筛为载体,采用浸渍法制备了锰铈催化剂,对其低温NH3-SCR反应性能进行了评价,并采用XRD、BET、NH3-TPD、H2-TPR以及XPS对催化剂进行了表征。结果表明,三种分子筛负载的锰铈催化剂均具有较好的低温NH3-SCR反应活性,其中,Mn-Ce/USY的催化性能最好,在107℃时NOx转化率可达到90%。负载锰铈后催化剂的比表面积和孔体积均有所下降;活性组分MnOx主要以无定型态分布于催化剂表面,且在ZSM-5上检测到聚集的CeO2。催化剂表面弱酸对低温NH3-SCR反应起主要作用,催化剂表面上活性组分的表面浓度和氧化态明显不同,较高的Mn4+/Mn3+原子比和吸附氧表面浓度对提高催化剂的低温NH3-SCR反应活性有利。
Relationship between coal ash fusibility and ash composition in terms of mineral changes
WANG Yang, LI Hui, WANG Dong-xu, DONG Chang-qing, LU Qiang, LI Wen-yan
2016, 44(9): 1034-1042.  
[Abstract](478) [FullText HTML](258) [PDF 809KB](47)
摘要:
通过在一种真实煤灰中添加不同的氧化物或直接用氧化物配制合成灰,探究了不同灰成分对灰熔融特性的影响规律。利用FactSage 7.0对不同灰分的熔融过程进行了热力学模拟,通过熔融过程中的矿物质变化为各种灰成分对熔融特性的影响规律提供理论依据。结果表明,氧化钠对灰熔点的降低作用源于钠长石和霞石对钙长石的取代;氧化镁含量的增加对灰熔点起先降低后升高的作用,当氧化镁含量超过一定时,产生的镁橄榄石能够升高灰熔点;硫对灰熔点的升高作用源于镁橄榄石和硫酸钙对透辉石的取代;氧化钙含量的增加对灰熔点起到先降低后升高的作用,当氧化钙含量超过一定时,硅从熔点较低的矿物质迁移到熔点较高的矿物质中,升高了灰熔点。在与硅氧单元体结合的过程中,氧化钠优先于氧化钙;与氧化钙和硅氧单元体结合的氧化物的优先级为:氧化铝>氧化镁>氧化铁。
Effect of rare-earth element modification on the performance of Cu/ZnAl catalysts derived from hydrotalcite precursor in methanol steam reforming
YANG Shu-qian, HE Jian-ping, ZHANG Na, SUI Xiao-wei, ZHANG Lei, YANG Zhan-xu
2018, 46(2): 179-188.  
[Abstract](407) [FullText HTML](205) [PDF 7028KB](35)
摘要:
采用原位合成法在γ-Al2O3表面合成了锌铝水滑石,再通过顺次浸渍法制备了一系列掺杂稀土改性的MM=Y、La、Ce、Sm、Gd)/Cu/ZnAl催化材料,并将其应用于甲醇水蒸气重整制氢反应。探讨了稀土掺杂改性对Cu/ZnAl催化剂催化性能的影响,并采用XRD、SEM-EDS、BET、H2-TPR、XPS和N2O滴定等手段对催化剂进行了表征。结果表明,催化剂的活性与Cu比表面积和催化剂的还原性质密切相关,Cu比表面积越大,还原温度越低,催化活性越高。稀土Ce、Sm、Gd的引入能改善活性组分Cu的分散度、Cu比表面积以及催化剂的还原性质,进而提高催化剂的催化活性。其中,Ce/Cu/ZnAl催化剂表现出最佳的催化活性,在反应温度为250 ℃时,甲醇转化率达到100%,CO含量为0.39%,相比Cu/ZnAl催化剂,甲醇转化率提高了近40%。
Effects of NH3 and SO3 on the generation of ammonium bisulfate and ammonium sulfate
YANG Jian-guo, YANG Wei-ying, ZHENG Fang-dong, ZHAO Hong
2018, 46(1): 92-98.  
[Abstract](312) [FullText HTML](277) [PDF 865KB](35)
摘要:
通过建立具有更精确的SO3组分的实验室模拟烟气系统,同步研究了反应物浓度对硫酸氢铵和硫酸铵生成率和生成进度(生成速率)的影响。在实验浓度范围内,硫酸氢铵的开始生成温度为230-270℃,峰值温度为180-240℃,硫酸铵开始生成温度及峰值温度总体上比硫酸氢铵低40℃左右。硫酸氢铵的生成率明显高于硫酸铵,根据NH3和SO3浓度与物质的量比不同,烟温到120℃时,硫酸氢铵的生成率为64%-90%,硫酸铵的生成率为6%-15%,硫酸氢铵的生成率为硫酸铵的6-10倍。反应物浓度的增加会促进硫酸氢铵和硫酸铵的生成,且SO3较NH3更有利于硫酸氢铵的生成。硫酸氢铵和硫酸铵生成份额随温度的变化呈单峰状,且随着反应物浓度的增加,其峰值所在的温度区间逐渐升高。
Preparation of core-shell catalysts for one-step synthesis of dimethyl ether from syngas
WANG Wen-li, WANG Yan, CHEN Yue-xian, ZHAO Wen-chao, LI Rui-feng
2013, 41(08): 1003-1009.  
[Abstract](2388) [PDF 13334KB](54)
Abstract:
A core-shell catalyst CuO-ZnO-Al2O3@Al2O3 for one-step synthesis of dimethyl ether from synthesis gas was prepared using glucose, sucrose or starch as template, and characterized by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The thickness of the Al2O3 shell in the catalyst was altered by controlling the synthesis condition, such as temperature and time. The catalytic performance of dimethyl ether (DME) synthesized from CO hydrogenation on the catalysts were investigated. The conversion of CO and the selectivity of DME on CuO-ZnO-Al2O3@Al2O3 achieved 35.2% and 61.1% at 260 ℃, 5.0 MPa and 1 500 mL/(h·gcat), respectively.
Effect of wastewater treatment processes on thermal treatment properties of sewage sludge
JIE Li-Beng, Zheng-Shi-Mei, LI Chao
2009, 37(04): 501-505.  
[Abstract](1705) [PDF 1335KB](54)
Abstract:
The properties of pyrolysis and combustion for five different sewage sludges are studied by thermal gravimetric analysis at a heating rate of 10℃/min in the atomosphere of nitrogen and oxygen, respectively. The results show that both of the “anaerobic” wastewater treatment and the sludge anaerobic digestion make the organic compounds in sludge so complicated that the organic compounds decomposition and release temperature becomes higher during pyrolyzing, and the “aerobic + anaerobic” process makes the organic compounds in sludge more complicated than the “anaerobic +aerobic” process. There is no influence on the combustion process and the burnout point, but can make the combustion temperature of sludge higher. The thermal reaction mechanisms have been studied with šatava-šesták equation. It shows that the pyrolysis mechanism of these sludges is a process of volatile diffusion at first and then the chemical reaction function, while the combustion mechanism of them is a process of chemical reaction and diffusion function.