JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2014
·Vol. 90
·期 3
·415-422
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IF 2.494
Yanping Chen,Yiming Xu,Dang-guo Cheng,Yingcai Chen,Fengqiu Chen,Xiaoyong Lu,Yiping Huang,Songbo Ni
BACKGROUND The synthesis of C 2 –C 4 hydrocarbons from coal or biomass-derived syngas has received increasing attention because of the resource constraints of petroleum. The present study explores direct production of hydrocarbons from syngas over bifunctional catalyst containing methanol synthesis catalyst CuO–ZnO–Al 2 O 3 (CZA) and SAPO-34 zeolite. RESULTS The synthesis of C 2 –C 4 hydrocarbons from syngas was investigated over CZA/SAPO-34 bifunctional catalyst at temperatures ranging from 240 to 440°C. The results indicate that higher temperatures aggregate Cu metal and lead to the deactivation of CZA. The predominant products are dimethyl ether (DME) and methanol at temperatures from 280 to 360°C and a small amount of hydrocarbons are found due to the deactivation of SAPO-34 caused by a type of coke named ‘inert coke’. While 96.5% selectivity of C 2 –C 4 hydrocarbons in products of all hydrocarbons can be obtained at 400°C with less coke named ‘active coke’. CONCLUSION Reaction temperatures have significant effect on the selectivity of C 2 –C 4 hydrocarbons and coke species of SAPO-34. The ‘active coke’ of poly methyl-substituted benzene/naphthalene (MB/MN) acts both as an intermediate and as coke deposition. The ‘inert coke’ of poly methyl-substituted adamantine (MA) and other groups-substituted benzene/naphthalene acts only as coke depositions. Comprehensive consideration of the characteristics of this bifunctional catalyst, shows that a moderate temperature for C 2 –C 4 hydrocarbons synthesis from syngas might be approximately 400°C. © 2014 Society of Chemical Industry
研究领域:
化学工程
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催化化学
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产品关联
DOI
高影响因子
WASTE MANAGEMENT
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2025
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IF 7.1
Hongtao Wang,Zhibao Huo,Qiang Jin
The steel industry is responsible for 30 % of global industrial greenhouse gas emissions, which is mainly dependent on metallurgical coke utilization. Although biochar represents a promising carbon–neutral alternative, its suboptimal mechanical properties have hindered its direct substitution for conventional coke. This work introduces an innovative hydrothermal carbonization-repolymerization strategy to synthesize high-performance biocoke from sustainable feedstocks of oak residues and waste soybean oil. Our approach is centered on a novel and bio-based polymerization agent, synthesized by blending epoxidized soybean oil from oxidized waste oil and tannic acid extracted from oak residues in a 3:1 mass ratio. The epoxidized soybean oil-tannic acid effectively undergoes cross-linking reactions with oak biochar and oak bio-oil that both in-situ generated from the hydrothermal carbonization, resulting in a highly cross-linked biocoke. The ESO undergoes epoxy ring-opening in the cross-polymerization reaction, providing more reaction sites for cross-linked reactions. Moreover, the resulting biocoke shows a significant aromatization and graphitization structure. Therefore, the biocoke displays superior mechanical and thermochemical properties, including crushing strength (86.0 % of M 40 ), abrasion resistance (6.6 % of M 10 ), coke strength after reaction (64.2 %), and higher heating value (40.79 MJ/kg), meeting the performance of first-grade metallurgical coke. A cradle-to-gate LCA indicates that substituting 50 % of metallurgical coke by biocoke results in a reduction of CO 2 emissions of 622.8 kg for per ton of iron production. This study not only provides a novel polymerization strategy for producing metallurgical-grade biocoke but also highlights its potential to significantly reduce the carbon footprint of the steel industry.
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DOI
PubMed
高影响因子
RENEWABLE ENERGY
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2022
·
IF 8.634
Yuchen Jiang,Xianglin Li,Chao Li,Lijun Zhang,Shu Zhang,Bin Li,Shuang Wang,Xun Hu
Pyrolysis is a thermochemical route for converting waste plastics into hydrocarbons that might be further upgraded to fine chemicals via the process such as hydrotreatment. In this study, the pyrolysis of five typical plastics (PE, PP, PVC, PS and PET) and steam reforming of their derived volatiles were coupled in one process, named as pyro-reforming. The reaction behaviors, especially the property of their derived cokes, in the pyro-reforming were investigated. The results indicated that the volatiles from the pyrolysis of PE had the highest reactivity with steam to produce H 2 of the highest yield, followed by that of PP, PVC, PET and PS. The Cl in PVC promoted nickel sintering, enhanced formation of heavy aromatics through aromatization. Moreover, the existence of Cl interrupted formation of carbon nanotube, forming the highest amount of coke with hemp rope-like fiber form of very coarse surface. This was very different from the carbon nanotube form of coke with smooth surface and uniform outer/inner diameters from the pyro-reforming of PE or PP. The pyro-reforming of PET or PS generated mainly the aromatic intermediates that were chemically more inert in steam reforming, forming polymeric type of coke with no carbon nanotube morphology and very low crystallinity .
研究领域:
能源科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
WASTE MANAGEMENT
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2019
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IF 5.431
Chenyu Wang,Wei Zhu,Hao Zhang,Cheng Chen,Xihui Fan,Ying Su
The hydrothermal gasification of dewatered sewage sludge converts waste into syngas fuel (gas containing H 2 , CH 4 , CO, and CO 2 ), but the formation of char and tar by a side reaction restricts practical applications. In this study, the formation of char/tar by the hydrothermal gasification of dewatered sewage sludge at 300–400 °C for 5–90 min with a heating rate of 8–50 °C/min is investigated. The results showed that the formation of tar/char reached equilibrium after 30 min, and an increase in the temperature and heating rate reduced the char yield. However, a higher tar yield was achieved at the highest temperature. Experiments on sludge with different moisture contents were also conducted, and the formation of char/tar was inhibited at a higher moisture content. The addition of NaOH and H 2 O 2 can effectively reduce the char and tar yields, respectively. A lumped kinetic model for describing carbon conversion during the hydrothermal gasification of sewage sludge was developed to elucidate the char/tar formation mechanism. The experimental data were used to determine the model parameters, and the fitting results showed that solid–solid conversion from organic matter in sludge was the predominant char/tar formation pathway, with an activation energy of 7.1 kJ/mol. The experiments using the model compounds indicated that humus and protein are the main precursors of char and tar, respectively. This study provides insights for understanding the formation of char/tar from sewage sludge following hydrothermal gasification, which is vital for controlling the formation of char and tar to improve the gasification efficiency.
研究领域:
环境科学
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能源工程
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DOI
PubMed
高影响因子
Chemical Science
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2018
·Vol. 9
·期 14
·3426-3437
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IF 9.063
Xinyu Li,Zhi-Jian Zhao,Liang Zeng,Jiubing Zhao,Hao Tian,Sai Chen,Kang Li,Sier Sang,Jinlong Gong
La2O3 exhibits good performance for various catalytic applications, such as oxidative coupling of methane (OCM) and dry reforming of methane (DRM), during which coke formation may lead to the deactivation of catalysts. Typically, the reaction between CO2 adsorbed on La2O3 and coke is the rate-determining step of the coke elimination process. This paper describes the influence of Ce addition on the CO2 adsorption and activation over La2O3. Combined with in situ and ex situ characterization and density functional theory (DFT) calculation, we show that Ce addition promotes the formation of bidentate carbonate on La2O3via tuning CO2 adsorption energy. In addition, Ce addition adjusts the ratio of bidentate/monodentate carbonate, and affects the ratio of hexagonal/monoclinic La2O2CO3 on the binary oxides. DRM is used as a probe reaction to examine the coke elimination performance of Ce–La binary oxide. It is found that when the Ce/La ratio reaches the optimal value (0.15), Ce–La binary oxide has the highest CO2 adsorption energy and predominantly promotes the formation of bidentate carbonate, and hence possesses the highest basicity above 700 °C and finally exhibits the best coke elimination performance.
研究领域:
催化化学
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材料科学
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DOI
PubMed
高影响因子
FUEL
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2020
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IF 5.578
Ruonan Zheng,Dong Liu,Junshi Tang,Qiang Song,Qiang Yao
Coke formation during the process of in-situ combustion is affected by clay minerals, among which montmorillonite shows the most significant effect. A fixed-bed reactor was used to conduct the thermal conversion experiments of heavy oil and model compounds to reveal the mechanism of montmorillonite affecting the coke formation. Under the inert atmosphere, in the presence of montmorillonite, the temperature at which aromatic C–C groups of coke appeared decreased from 500 °C to 450 °C and polymers were formed when toluene was heated, indicating that montmorillonite catalyzed aromatization and polymerization, respectively. The increase in the supporter surface area promoted the formation of coke from pyrolysis by shortening the induction of coking. Under the oxidizing atmosphere, in the presence of montmorillonite, the initial temperature of O 2 consumed by heavy oil decreased from 270 °C to 250 °C, indicating that montmorillonite catalyzed oxygen-adding reaction. The temperature of CO x released by acetaldehyde and acetic acid decreased, and the release amounts increased, indicating that montmorillonite catalyzed decarbonylation and decarboxylation. Polymers were formed when acetaldehyde, acetic acid, ethanol, and acetone were heated, indicating that montmorillonite catalyzed polycondensation. When the oil mass fraction in the sample was within 18%, further increase in the supporter surface area did not affect the formation of coke from oxidation. The catalysis of montmorillonite was the main mechanism affecting coke formation during the thermal conversion of heavy oil under the inert and oxidizing atmospheres.
研究领域:
石油工程
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化学工程
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Wenrui Yan,Xinke Wang,Jianhua Dong,Yu Liu,Liuru Liu,Bo Wang,Quan Zhu
The active cooling technology based on endothermic hydrocarbon fuels can cause serious coking problems. Ammonia addition inhibits the coke formation at the mild fuel cracking. However, the mechanism of coke deposition under higher fuel conversion conditions remains unclear. Herein, the deep pyrolysis experiments of n-decane with ammonia addition was conducted using the electric heating method. The anti-coking performances of additives were obtained from the coking characteristics at different pyrolysis stages. The results indicate that under deep cracking conditions, the additive reacts with unsaturated free radicals produced by fuel cracking to produce aromatic heterocyclic compounds, inhibiting the formation and growth of polycyclic aromatic hydrocarbons (PAHs), thereby reducing the content of coking precursors. More importantly, the C-N compounds interact with the metals to form the spherical carbon with a predominant diamond structure, depositing as a thin film with passivation effect. As the reaction time proceeds, the film gradually smooths and maintains a thickness of about 4 μ m . In addition, passivation coating of TiN is used to further evaluate the effect of additives on the formation of surface coke. These results reveal that ammonia can ensure effective coking inhibition under long-term deep cracking conditions by affecting the growth of PAHs and coke surface.
研究领域:
化学工程
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能源科学
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产品关联
DOI
高影响因子
FUEL
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2024
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IF 6.7
Ji Mi,Peilun Wang,Hongshang Wang,Chongkun Shao,Zhiyuan Yuan,Jingkai Ma,Yongsheng Guo,Xufeng Lin,Wenjun Fang
Endothermic hydrocarbon fuels (EHFs) with high heat sink have revolutionized the thermal management technology of hypersonic aircraft over the past decades. In this work, highly stable quasi-homogeneous systems as a novel type of potential EHFs are introduced by dispersing water-rich multifunctional nanospheres in hydrocarbons. Studies conducted using cryo-transmission electron microscopy, dynamic light scattering and small-angle X-ray scattering have demonstrated that nanospheres with diameter less than 100 nm can be solubilized into hydrocarbons to form semi-transparent systems. They resist phase separation, remain stable under extreme centrifugal forces (exceeding 8000 RCF), and have low freezing points (subcooling temperature below −40 °C). In these quasi-homogeneous systems, the amphiphilic macromolecules within the multifunctional nanospheres serve dual roles: they stabilize the nanospheres and initiate the thermal cracking of the fuel, while the water component mitigates coking tendencies and contributes to the high heat sink. Ultimately, this novel fuel can achieve up to 19 % improvement in heat sink (from 3.42 MJ·kg −1 to 4.05 MJ·kg −1 at 3.5 MPa) and a 96.8 % reduction in coke formation (at 700 °C) with only a 9 % loss in volumetric heat value, without the need of catalysts.
研究领域:
材料科学
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航空工程
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
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IF 3.573
Zhirong Yang,Jing Zhang,Jiejie Huang,Gang Qian,Xuezhi Duan,Xinggui Zhou
To promote biomass-derived tar and coke upgrading, biomass pyrolysis intensification was utilized by the co-pyrolysis of biomass and caking coal with suitable particle size. The intensification led to a 15% increase in light tar fraction in tar, indicating a transformation from heavy tar to light components (phenols, aliphatic hydrocarbons). Moreover, the resulting coke achieved high strength (M25 > 80%) that can meet the requirement for moving bed gasification. To further facilitate tar upgrading and alleviate secondary reactions of volatiles that result in more secondary-coke and less gas, calcium-based Ca@Cu catalysts were synthesized and then loaded along the predicted coke cracks to improve tar quality without compromising coke granularity and strength. The results indicated that the catalytic upgrading mitigated the formation of pyrolytic water and secondary-coke, and dramatically improved tar quality as the light tar fraction in tar increased by 15–30%. Specifically, the upgraded light tar contains more phenols, naphthalenes, and anthracenes but less acids, ketones, and furfurals. It was postulated that selective cleavage of oxygen-containing functional groups (mainly ether bonds) promoted tar reconstruction to release more light aromatics during the catalysis. The coke strength continued to increase by 3–6%, possibly due to mitigation of H2O formation as indicated by more oxygen-containing groups retained in the aromatics during the Ca@Cu catalysis. The current study provided a new strategy to simultaneously upgrade coke and tar during catalytic pyrolysis of biomass for efficient utilization of the biomass.
研究领域:
能源与燃料
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催化化学
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产品关联
DOI
高影响因子
ACS Applied Electronic Materials
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2024
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IF 4.3
Pengfei Li,Dada Yang,Hongyue Chen,Yangxi Bai,Yang Hou,Qiaorui Sheng,Shuai Zhu
Graphene has exceptional electrical and mechanical properties, which make it an ideal material for wearable flexible strain sensors. However, its efficient and eco-friendly production remains constrained by challenges such as a complex process, high cost, and environmental pollution. To address those issues, this study proposes an ultrasonic ball milling method in a NMP bath using NMP as a solvent, incorporating alumina abrasive as microballs and stearic acid as interlayer additives to exfoliate coke into coke-based graphene. The resultant coke-based graphene is employed in the fabrication of sandwich-type flexible strain sensors. Tests indicate that the sensor exhibits excellent tensile strain (0–20%) and pressure strain (0–1000 kPa) sensing performances, maintaining stable operation after 500 tensile tests and 500 pressure tests, with quick response times (tensile strain response time: 257/353 ms, pressure strain response time: 192/256 ms). When applied to the human body, it can monitor the relative changes in resistance due to movement and the stimulus signals caused by external factors on the skin’s surface. This method holds significant application value for the eco-friendly and low cost preparation of graphene, enabling high-quality and large-scale production of graphene strain flexible sensors.
研究领域:
材料科学
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传感器技术
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
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2018
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IF 3.956
Shiyou Xing,Pengmei Lv,Che Zhao,Ming Li,Lingmei Yang,Zhongming Wang,Yong Chen,Shijun Liu
Non-H 2 and solvent-free catalytic conversion of waste lipids to liquid hydrocarbons is of great interest because of the associated low-cost, full-safety, and easy-operability. In this work, a solvent-free catalytic process for deoxygenating oleic acid was performed in H 2 and non-H 2 (N 2 , CH 4 , and CO 2 ) media over nano-Ni/HZSM-5. 8-Heptadecene, a primary product obtained at 320 °C in four media, was derived from the straightforward decarboxylation of oleic acid. In non-H 2 medium at 360 °C, the formation of C 8 –C 15 alkanes was enhanced, with yields of ca. 65.05 mol%, 70.71 mol%, and 73.09 mol% for N 2 , CH 4 , and CO 2 , respectively. A low yield of 49.67 mol% C 8 –C 15 alkanes in H 2 medium suggested that the H 2 medium reduced catalytic cracking . This was due to the preferential formation of stable heptadecane from 8-heptadecene in the presence of abundant H 2 . The absence of H 2 favored the cracking of 8-heptadecene. These cracked products were further converted to C 8 –C 15 alkanes, for which a mass supply of hydrogen was mandatory. Gas-phase reactions including methanation , Fisher-Tropsch (F-T) synthesis, and water-gas shift (WGS) reactions between deoxygenated gas products and reaction media provided significant pathways for the hydrogen required for the formation of alkanes. The CH 4 medium also acted as a hydrogen source due to its decomposition, catalyzed by nano-Ni/HZSM-5. Coke was substantially formed in all the four media. It was highlighted that the medium of H 2 favored the formation of aliphatic cokes, whereas the non-H 2 media, particularly the CO 2 medium, facilitated aromatic coke species on account of its weak oxidizability. Additionally, there was a severe loss of loaded Ni nanoparticles under H 2 medium but a slight Ni loss in CO 2 medium, which was proposed to the reason of aromatic cokes formation at the catalyst surface , acting as a trap for the loaded Ni nanoparticles.
研究领域:
化学工程
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能源科学
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DOI
高影响因子
ENERGY & FUELS
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2018
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IF 3.024
Ruonan Zheng,Jingjun Pan,Lijuan Chen,Junshi Tang,Dong Liu,Qiang Song,Long Chen,Qiang Yao
In situ combustion is an enhanced method to recover heavy oil. The formation and oxidation of coke are crucial to promote the combustion front. Heavy oil from China and montmorillonite, a major type of clay, were used as samples in this study. The thermogravimetric analyzer (TGA) was applied to temperature-programmed oxidation/pyrolysis experiments to study the effect of montmorillonite on the thermal conversion characteristics of heavy oil. A fixed-bed reactor was then used to obtain coke and study the effect of montmorillonite on coke properties. The characteristic temperatures of thermal conversion decreased with montmorillonite in the oxidizing atmosphere but remained unaffected in the pyrolysis atmosphere. The fuel deposition increased in both atmospheres because of montmorillonite’s strong adsorption. In the oxidizing atmosphere, the presence of montmorillonite obviously promoted the progress of coke formation and increased coke yield. The content of O was increased, and the contents of C and H were decreased in coke. The oxidation activity of coke was improved, while trailing occurred due to the blocking in the pore structures of the montmorillonite skeleton. In the pyrolysis atmosphere, the presence of montmorillonite did not influence the coke formation temperature but increased the coke yield. The content of C was increased and the contents of H and O were decreased in coke. Coke oxidation activity was reduced with the more serious trailing phenomenon. Montmorillonite significantly affected coke formation through its strong adsorption to polar components in heavy oil in both atmospheres and obvious catalysis on dehydrogenation as an acid catalyst in the pyrolysis atmosphere, while it enhanced the oxygenation due to its large surface area and catalyzed polycondensation in the oxidizing atmosphere.
研究领域:
石油工程
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化学工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）