Article
Thermodynamics
Mansur Aliyu, Ahmed Abdelhafez, Medhat A. Nemitallah, Syed A. M. Said, Mohamed A. Habib
Summary: This study compares the combustion characteristics of premixed methane oxygen-enriched air and oxymethane in a gas-turbine model combustor. The results show that both CO2 and N-2 flames experience blowout at constant adiabatic temperature, with CO2 flames having a higher blowout OF value. The stable combustion zone of CO2 flames is larger than that of N-2 flames.
Article
Chemistry, Physical
Ethan S. Hecht, Bikram Roy Chowdhury
Summary: The study measured the visible flame length and heat-flux characteristics of cryogenic hydrogen flames released from high-aspect ratio nozzles, finding that the aspect ratio of the release does not significantly affect the flame length or heat flux.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Energy & Fuels
Tao Shu, Yuan Xue, Zijun Zhou, Zhuyin Ren
Summary: Experimental investigation of flame properties in ammonia/methane/air mixtures shows significant influence of gas composition and pressure on flame speeds and flammability limits. Linear correlation between flame speed and methane volume fraction is observed, with accurate prediction using Okafor et al. mechanism.
Article
Energy & Fuels
Chunxiang Liu, Tairun Lai, Hao Zhang, Ping Huang, Kaihong Lin, Yuchao Lin, Man Li
Summary: This paper investigates the morphology of turbulent diffusion flames under slope conditions with varying aspect ratios. The results show that the presence of a slope affects the flame tilt angle, flame length, and flame height. Additionally, new models considering the slope angle and aspect ratio of the fire source are established and verified.
Article
Energy & Fuels
Tao Chen, Suyuan Yu, Yu Cheng Liu
Summary: The study investigates the effects of Soret diffusion on hydrogen-air edge flame propagation and diffusion-chemistry interaction through simulation. It demonstrates that Soret diffusion significantly influences the relationships between flame displacement speed and flame curvature, stretch rate, and scalar dissipation rate. Additionally, Soret diffusion weakens the chemical reaction component in edge flame propagation and affects the diffusion of hydrogen and hydrogen-2 in opposite ways.
Article
Thermodynamics
Alireza Rahbari, Sajad Homayoonfar, Esmaeil Valizadeh, Mohammad Reza Aligoodarz, Davood Toghraie
Summary: The major challenge in the development of micro-combustors is flame instabilities, which lead to non-uniform wall temperature distribution and lower combustion efficiency. This research investigates the combustion characteristics and geometrical configurations on flame stability and combustion efficiency, with a detailed chemical reaction mechanism developed and parametric study conducted. Increasing thermal conductivity coefficient, equivalence ratio, and using a micro-combustor with bluff body are identified as effective ways to improve combustion performance.
Article
Energy & Fuels
Huanhuan Xu, Yi Ge, Shouyan Chen, Fanxing Meng, Zilin Zhu, Xiaohan Ren
Summary: Hydrogen has the potential to contribute to a CO2-neutral future, but the transition from conventional fossil fuels to hydrogen faces challenges related to the variation in hydrogen content and safety issues. The concept of multiple-injection combustors addresses these challenges by providing flexible nozzle distance and low flash-back risk. This study focuses on the flame interaction behavior of two identical slot jet hydrogen/carbon monoxide diffusion flames and investigates the effects of burner separating distance, fuel composition, and fuel velocity.
Article
Thermodynamics
Tao Shu, Yuan Xue, Wenkai Liang, Zhuyin Ren
Summary: The modified models MLC and MNQ show improved accuracy in predicting flame speeds and Markstein lengths, especially for lean hydrogen/air flames. As pressure increases, both unmodified and modified models can reduce uncertainty and the impact of finite flame structure becomes less significant.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
Qiang Wang, Longhua Hu, Fei Tang, Adriana Palacios, Suk Ho Chung
Summary: The lifted flame behavior of inclined turbulent jets was experimentally investigated by varying the inclination angle of non-premixed fuel jets. The results showed that the lift-off length increases linearly with the increase in initial fuel jet velocity at a fixed inclination angle. A physical model was developed to quantify the lift-off length, taking into account the effect of jet inclination angle.
COMBUSTION AND FLAME
(2023)
Article
Engineering, Civil
Kaiyuan Li, Zhuangzhuang Ma, Xinyan Huang, Yanyan Zou
Summary: This study investigates the merging characteristics of two identical linear diffusion flames, finding that the merging probability and merging flame height are related to flame spacing and heat release rate. A new dimensionless heat release rate parameter is proposed, and it is observed that decreasing entrained air from the ground facilitates flame merging. The merging flame height is determined by the competition of buoyancy and pressure difference, and can be correlated with the effective entrainment perimeter and dimensionless heat release rate.
FIRE SAFETY JOURNAL
(2022)
Article
Energy & Fuels
Gyu Jin Hwang, Dong Seok Jeon, Nam Il Kim
Summary: The effects of pressure on the characteristics of propane flame were examined, and it was found that extending the pressure range allows for more precise and abundant experimental results, revealing the general features of flame structures and explaining the non-monotonic variation in flame height and variations in flame structure during the transition from laminar lifted flame to turbulent lifted flame.
Article
Energy & Fuels
Tao Chen, Suyuan Yu, Yu Cheng Liu
Summary: The study investigates the effects of pressure on the propagation of laminar edge flames, revealing the linear relationship between flame curvature and equivalence ratio gradients (V phi). Flame stretch is shown to be dominated by flow strain and flame curvature, with increasing pressure leading to larger curvature and stronger flow strain. The study also highlights the negative correlation between local flame speed and flame curvature under different pressures. Global flame speed shows non-monotonic behavior with increasing V phi, mainly due to variations in upstream velocity reduction.
Article
Thermodynamics
Maria Castela, Alam Garciduenas Correa, Jason S. Damazo, Deanna A. Lacoste
Summary: Experimental study on thermoacoustic coupling of methane flames in small diameter tubes revealed that thermoacoustic instability impacts flame propagation and can lead to flame quenching. Depending on the tube length (acoustics), flames either fully propagate or extinguish prematurely.
COMBUSTION AND FLAME
(2021)
Article
Thermodynamics
Cheng Chi, Wang Han, Dominique Thevenin
Summary: Ammonia (NH3) shows promise as a carbon-free energy carrier and can be used as a fuel in gas turbines for power generation. This study investigates the impact of molecular diffusion modeling (MDM) on turbulent premixed NH3/H2/air jet flames, focusing on flame structure, NO production, and the combined role of MDM and stretch rate. The results show that MDM has a significant influence on NO production and turbulent flame speed, while having negligible impact on major species and NO distribution. Flame curvature and strain are found to be critical factors in accurately predicting NO emission and NH3/H2/air flame propagation.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Chemistry, Physical
Weiguo Cao, Wenjuan Li, Yun Zhang, Zhuanghong Zhou, Yiming Zhao, Zhenxin Yang, Xuansen Liu, Shuo Yu, Yingxin Tan
Summary: The explosion characteristics of premixed syngas-air mixtures in ducts were studied experimentally. The ratio of L/H and H-2/CO had significant effects on the explosion flame behaviors. Venting pressure affected overpressure dynamics, which increased with L/H ratio and H-2/CO ratio.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Energy & Fuels
Yingna Du, Chen Huang, Wei Jiang, Qiangwei Yan, Yongfei Li, Gang Chen
Summary: In this study, anionic surfactants modified hydrotalcite was used as a flow improver for crude oil under low-temperature conditions. The modified hydrotalcite showed a significant viscosity reduction effect on crude oil. The mechanism of the modified hydrotalcite on viscosity and pour point of crude oil was explored through characterization and analysis of the modified hydrotalcite and oil samples.
Article
Energy & Fuels
Mohammad Saeid Rostami, Mohammad Mehdi Khodaei
Summary: In this study, a hybrid structure, MIL-53(Al)@MWCNT, was synthesized by combining MIL-53(Al) particles and -COOH functionalized multi-walled carbon nanotube (MWCNT). The hybrid structure was then embedded in a polyethersulfone (PES) polymer matrix to prepare a mixed matrix membrane (MMM) for CO2/CH4 and CO2/N2 separation. The addition of MWCNTs prevented MIL-53(Al) aggregation, improved membrane mechanical properties, and enhanced gas separation efficiency.
Article
Energy & Fuels
Yunlong Li, Desheng Huang, Xiaomeng Dong, Daoyong Yang
Summary: This study develops theoretical and experimental techniques to determine the phase behavior and physical properties of DME/flue gas/water/heavy oil systems. Eight constant composition expansion (CCE) tests are conducted to obtain new experimental data. A thermodynamic model is used to accurately predict saturation pressure and swelling factors, as well as the phase boundaries of N2/heavy oil systems and DME/CO2/heavy oil systems, with high accuracy.
Article
Energy & Fuels
Morteza Afkhamipour, Ebad Seifi, Arash Esmaeili, Mohammad Shamsi, Tohid N. Borhani
Summary: Non-conventional amines are being researched worldwide to overcome the limitations of traditional amines like MEA and MDEA. Adequate process and thermodynamic models are crucial for understanding the applicability and performance of these amines in CO2 absorption, but studies on process modeling for these amines are limited. This study used rate-based modeling and Deshmukh-Mather method to model CO2 absorption by DETA solution in a packed column, validated the model with experimental data, and conducted a sensitivity analysis of mass transfer correlations. The study also compared the CO2 absorption efficiency of DETA solution with an ionic solvent [bmim]-[PF6] and highlighted the importance of finding optimum operational parameters for maximum absorption efficiency.
Article
Energy & Fuels
Arastoo Abdi, Mohamad Awarke, M. Reza Malayeri, Masoud Riazi
Summary: The utilization of smart water in EOR operations has gained attention, but more research is needed to understand the complex mechanisms involved. This study investigated the interfacial tension between smart water and crude oil, considering factors such as salt, pH, asphaltene type, and aged smart water. The results revealed that the hydration of ions in smart water plays a key role in its efficacy, with acidic and basic asphaltene acting as intrinsic surfactants. The pH also influenced the interfacial tension, and the aged smart water's interaction with crude oil depended on asphaltene type, salt, and salinity.
Article
Energy & Fuels
Dongao Zhu, Kun Zhu, Lixian Xu, Haiyan Huang, Jing He, Wenshuai Zhu, Huaming Li, Wei Jiang
Summary: In this study, cobalt-based metal-organic frameworks (Co-based MOFs) were used as supports and co-catalysts to confine the NHPI catalyst, solving the leaching issue. The NHPI@Co-MOF with carboxyl groups exhibited stronger acidity and facilitated the generation of active oxygen radicals O2•, resulting in enhanced catalytic activity. This research provides valuable insights into the selection of suitable organic linkers and broadens the research horizon of MOF hybrids in efficient oxidative desulfurization (ODS) applications.
Article
Energy & Fuels
Edwin G. Hoyos, Gloria Amo-Duodu, U. Gulsum Kiral, Laura Vargas-Estrada, Raquel Lebrero, Rail Munoz
Summary: This study investigated the impact of carbon-coated zero-valent nanoparticle concentration on photosynthetic biogas upgrading. The addition of nanoparticles significantly increased microalgae productivity and enhanced nitrogen and phosphorus assimilation. The presence of nanoparticles also improved the quality of biomethane produced.
Article
Energy & Fuels
Yao Xiao, Asma Leghari, Linfeng Liu, Fangchao Yu, Ming Gao, Lu Ding, Yu Yang, Xueli Chen, Xiaoyu Yan, Fuchen Wang
Summary: Iron is added as a flocculant in wastewater treatment and the hydrothermal carbonization (HTC) of sludge produces wastewater containing Fe. This study investigates the effect of aqueous phase (AP) recycling on hydrochar properties, iron evolution and environmental assessment during HTC of sludge. The results show that AP recycling process improves the dewatering performance of hydrochar and facilitates the recovery of Fe from the liquid phase.
Article
Energy & Fuels
He Liang, Tao Wang, Zhenmin Luo, Jianliang Yu, Weizhai Yi, Fangming Cheng, Jingyu Zhao, Xingqing Yan, Jun Deng, Jihao Shi
Summary: This study investigated the influence of inhibitors (carbon dioxide, nitrogen, and heptafluoropropane) on the lower flammability limit of hydrogen and determined the critical inhibitory concentration needed for complete suppression. The impact of inhibitors on explosive characteristics was evaluated, and the inhibitory mechanism was analyzed with chemical kinetics. The results showed that with the increase of inhibitor quantity, the lower flammability limit of hydrogen also increased. The research findings can contribute to the safe utilization of hydrogen energy.
Article
Energy & Fuels
Zonghui Liu, Zhongze Zhang, Yali Zhou, Ziling Wang, Mingyang Du, Zhe Wen, Bing Yan, Qingxiang Ma, Na Liu, Bing Xue
Summary: In this study, high-performance solid catalysts based on phosphotungstic acid (HPW) supported on Zr-SBA-15 were synthesized and evaluated for the one-pot conversion of furfural (FUR) to γ-valerolactone (GVL). The catalysts were characterized using various techniques, and the ratio of HPW and Zr was found to significantly affect the selectivity of GVL. The HPW/Zr-SBA-15 (2-4-15) catalyst exhibited the highest GVL yield (83%) under optimized reaction conditions, and it was determined that a balance between Bronsted acid sites (BAS) and Lewis acid sites (LAS) was crucial for achieving higher catalytic performance. The reaction parameters and catalyst stability were also investigated.
Article
Energy & Fuels
Michael Stoehr, Stephan Ruoff, Bastian Rauch, Wolfgang Meier, Patrick Le Clercq
Summary: As part of the global energy transition, an experimental study was conducted to understand the effects of different fuel properties on droplet vaporization for various conventional and alternative fuels. The study utilized a flow channel to measure the evolution of droplet diameters over time and distance. The results revealed the temperature-dependent effects of physical properties, such as boiling point, liquid density, and enthalpy of vaporization, and showed the complex interactions of preferential vaporization and temperature-dependent influences of physical properties for multi-component fuels.
Article
Energy & Fuels
Yuan Zhuang, Ruikang Wu, Xinyan Wang, Rui Zhai, Changyong Gao
Summary: Through experimental validation and optimization of the chemical kinetic model, it was found that methanol can accelerate the oxidation reaction of ammonia, and methanol can be rapidly oxidized at high concentration. HO2 was found to generate a significant amount of OH radicals, facilitating the oxidation of methanol and ammonia. Rating: 7.5/10.
Article
Energy & Fuels
Radwan M. EL-Zohairy, Ahmed S. Attia, A. S. Huzayyin, Ahmed I. EL-Seesy
Summary: This paper presents a lab-scale experimental study on the impact of diethyl ether (DEE) as an additive to waste cooking oil biodiesel with Jet A-1 on combustion and emission features of a swirl-stabilized premixed flame. The addition of DEE to biodiesel significantly affects the flame temperature distribution and emissions. The W20D20 blend of DEE, biodiesel, and Jet A-1 shows similar flame temperature distribution to Jet A-1 and significantly reduces UHC, CO, and NOx emissions compared to Jet A-1.
Article
Energy & Fuels
Jiang Bian, Ziyuan Zhao, Yang Liu, Ran Cheng, Xuerui Zang, Xuewen Cao
Summary: This study presents a novel method for ammonia separation using supersonic flow and develops a mathematical model to investigate the condensation phenomenon. The results demonstrate that the L-P nucleation model accurately characterizes the nucleation process of ammonia at low temperatures. Numerical simulations also show that increasing pressure and concentration can enhance ammonia condensation efficiency.
Article
Energy & Fuels
Shiyuan Pan, Xiaodan Shi, Beibei Dong, Jan Skvaril, Haoran Zhang, Yongtu Liang, Hailong Li
Summary: Integrating CO2 capture with biomass-fired combined heat and power (bio-CHP) plants is a promising method for achieving negative emissions. This study develops a reliable data-driven model based on the Transformer architecture to predict the flowrate and CO2 concentration of flue gas in real time. The model validation shows high prediction accuracy, and the potential impact of meteorological parameters on model accuracy is assessed. The results demonstrate that the Transformer model outperforms other models and using near-infrared spectral data as input features improves the prediction accuracy.