Article
Energy & Fuels
Kang Pan, James Wallace
Summary: The study revealed that fuel injection duration, injector nozzle size, and injection angle can significantly impact natural gas combustion characteristics. Shorter injection duration reduces peak cylinder pressure and emissions, but insufficient injected fuel mass may lead to flame propagation failure. Injector nozzle size influences combustion type, with small nozzles inducing diffusion combustion and large nozzles inducing partially premixed combustion. Fuel injection angle affects combustion by modifying flame propagation from the glow plug shield.
Article
Chemistry, Physical
Lin Chen, Xiao Zhang, Ren Zhang, Jinguang Li, Jiaying Pan, Haiqiao Wei
Summary: In this study, the inner mechanism of hydrogen direct injection on methane combustion was optically studied, and it was found that hydrogen addition can improve the lean combustion effect and thermal efficiency of methane engines. However, the choice of hydrogen injection timing has an important impact on engine performance.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Multidisciplinary
Qin Chen, Zhaolei Zheng, Ziji Zhu
Summary: A detailed mechanism was developed to study the combustion of syngas/gasoline blends, considering the mixing ratio of syngas and the H2/CO ratio. Syngas addition promoted ignition at high temperatures but caused a delay at low temperatures. The addition of syngas inhibited knock combustion, increased radical concentrations, and promoted laminar flame speed. However, it also led to a decrease in total heat release and an increase in CO emissions.
Article
Energy & Fuels
Qian Zeng, Qiangling Duan, Kaiqiang Jin, Mengyuan Zhu, Jinhua Sun
Summary: This paper investigates the effects of nitrogen addition on self-ignition of high-pressure hydrogen leakage, showing that an increase in nitrogen addition reduces the likelihood of self-ignition events and external tube flame formation, with a critical threshold for overpressure. Impurity gases have a similar impact on self-ignition possibilities as they do on shock intensity, with the reduction in self-ignition primarily attributed to the decrease in shock intensity and enhanced with higher fuel molecular weight. Additionally, nitrogen addition inhibits flame development and propagation inside the tube, with ignited flames barely surviving expansion outside the tube.
Article
Thermodynamics
D. Ebi, R. Bombach, P. Jansohn
Summary: Operating lean-premixed gas turbine burners with fuels containing large amounts of hydrogen can increase the risk of flame flashback. This study focuses on understanding the mechanisms and impact of flashback in methane-hydrogen air flames, and the findings suggest that the flame propagation pathway and flow-flame interaction for flashback are different compared to previous studies on swirl flames. High-speed imaging and laser diagnostics are used to characterize the flame behavior and flashback limits are measured at elevated pressure and preheat temperature to quantify the increase in flashback propensity with increased hydrogen content.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Haiyue Li, Wenkai Liang, Chung K. Law
Summary: This study investigates the effects of additive ozone on the ignition and propagation of premixed hydrogen/oxygen flames. The results demonstrate that ozone-enhanced flames have a unique triple reaction layer structure and lead to multi-regime flame dynamics. The study also notes the modification of the minimum ignition energy in ozone-assisted flames.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Wenwen Wei, Gesheng Li, Zunhua Zhang, Yanxiang Long, Hanyuyang Zhang, Yong Huang, Mengni Zhou, Yi Wei
Summary: The study aims to discuss the optimization direction and evaluate the greenhouse gas emission reduction potentials of NG engines blending with ammonia. The effects of ammonia volume fraction and excess air ratio on the performance and emission characteristics of a spark-ignition marine NG engine were investigated. Results show that increasing ammonia volume fraction can help reduce in-cylinder pressure and heat release rate, improve brake thermal efficiency, and reduce CO2 emissions, but increase NOx, CH4, NH3, and N2O emissions.
Article
Thermodynamics
Javad Zareei, Abbas Rohani, Farhad Mazari, Maria Vladimirovna Mikkhailova
Summary: This study investigates the effect of two-step fuel injection on a four-cylinder engine using an HCNG blend as fuel. Results show that injecting HCNG blend can increase power, reduce fuel consumption and emissions, and decrease carbon monoxide and unburned hydrocarbons during complete combustion.
Article
Thermodynamics
Kang Pan, James Wallace
Summary: This study validates a modified multi-step phenomenological soot model and an enhanced combustion model for direct-injection natural gas engines. The computational models accurately predict the combustion and emission characteristics of natural gas engines and can be used for further investigations.
INTERNATIONAL JOURNAL OF ENGINE RESEARCH
(2022)
Article
Energy & Fuels
Zhaojun Zhu, Yikai Li, Cheng Shi
Summary: Increasing the natural gas energy fraction (NGEF) delays the start of combustion and decreases peak pressure; NGEF significantly affects the distribution of the ignition kernel, with higher NGEF scattering the ignition kernel; Lower soot volume fraction and unburned hydrocarbon emissions can be obtained by increasing NGEF from 0% to 70%, but further increasing NGEF to 85% deteriorates combustion.
Article
Energy & Fuels
Kang Pan, James S. Wallace
Summary: The impact of hydrogen post-injection on combustion emission characteristics in a glow plug assisted direct-injection natural gas engine was investigated. The results showed that hydrogen post-injection can reduce methane and soot emissions, increase carbon monoxide emissions, and reduce carbon dioxide emissions. It was also found that a minimum amount of hydrogen is required to effectively reduce soot emissions.
Article
Chemistry, Physical
Yan Zhao, Brendan Hickey, Shubham Srivastava, Valeriy Smirnov, Vincent McDonell
Summary: The study investigated the effects of adding renewable hydrogen to natural gas on the performance of a surface burner, showing that replacing a portion of natural gas with hydrogen had minimal impact on burner performance parameters without modifying the burner geometry.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Physical
Yi Qin, Xiaowei Chen
Summary: This paper conducts a numerical study of flame propagation during hydrogen explosion in a closed duct with obstacles, showing that the flame speed is proportional to the number of obstacles, and the flame undergoes different stages of evolution during the explosion process.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Physical
Sanghyeok Kwak, Jaehong Choi, Myunggeun Ahn, Youngbin Yoon
Summary: The effects of hydrogen addition on the forced response of H-2/CH4 flames in a dual-nozzle swirl-stabilized combustor are analyzed. The study shows that the flame transfer function (FTF) characteristics are determined by the change in flame angle and the flame roll-up phenomenon, with the latter playing a more important role. In addition, hydrogen addition attenuates the local maximum gains and decreases the FTF phase slope. These differences are primarily attributed to the change in flame roll-up behavior induced by a short and compact flame distribution at high hydrogen contents.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Energy & Fuels
Li Guo, Ming Zhai, Qianhao Shen, Hongkun Guo, Peng Dong
Summary: This study investigates the effect of hydrogen addition on the ionization of partially premixed methane flame. It finds that hydrogen addition can promote flame ionization, but the effect weakens when the hydrogen content reaches 50% of the total fuel amount. Furthermore, the impact of hydrogen addition on ionization is influenced by the amount of primary premixed air.
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.