Article
Engineering, Environmental
Kubilay Bayramoglu, Guner Ozmen
Summary: SCR systems are effective in reducing NOX emissions in internal combustion engines by analyzing the performance parameters of marine SCR systems using computational fluid dynamics (CFD). Increasing the amount of injected urea-water solution reduces NOX emissions but increases the risk of NH3 slip, while increasing the opening of the SCR bypass valve reduces pressure loss. However, increasing the bypass valve opening reduces NOX reduction performance and increases NH3 slip.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2021)
Article
Engineering, Multidisciplinary
Lukasz Jan Kapusta, Rafal Rogoz, Jakub Bachanek
Summary: This study applied flash boiling to low-pressure injection of a urea-water solution (UWS) and investigated its influence on the selective catalytic reduction (SCR) system performance through numerical simulations. The research found that flash boiling can improve the performance of SCR systems, but directly increasing the temperature of UWS may have the opposite effect.
ATOMIZATION AND SPRAYS
(2021)
Article
Engineering, Chemical
Apoorv Kalyankar, Jacob Backhaus, Achuth Munnannur, Z. Gerald Liu
Summary: This study conducted spray simulations based on an Eulerian-Lagrangian framework to predict the uniformity of ammonia in a urea-based SCR system. The simulations were validated against laser absorption tomography measurements and achieved excellent correlation with the measured data. By using a sufficiently long simulation time, quasi-steady temperature and wallfilm distribution profiles were obtained. The simulation runtime was reduced using a database approach and frozen field approximation.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Engineering, Chemical
Piqiang Tan, Xiaoyu Li, Shiyan Wang, Zhiyuan Hu, Diming Lou
Summary: In this study, the failure of SCR due to a low NH3-NOx ratio was systematically investigated through experiments, with major causes including insufficient urea injection, catalyst hydrothermal aging, and urea crystallization. The NOx conversion efficiency in the SCR system was found to increase with higher NH3-NOx ratio, but with an increase in ammonia leakage. Different factors influenced NOx conversion efficiency under different NH3-NOx ratios.
CHINESE JOURNAL OF CHEMICAL ENGINEERING
(2021)
Article
Thermodynamics
Surendran Mikhil, Shamit Bakshi, T. N. C. Anand
Summary: A simple computational model was developed to predict the vaporization rates of urea-water-solution droplets in a hot air stream, with reasonable accuracy. The model was able to capture the two-stage vaporization behavior of the droplets, but the accuracy of the second-stage vaporization rates depended significantly on the methods used to estimate fluid properties.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Energy & Fuels
Nalini Kanta Mukherjee, Hardikk Valera, Sarat Unnithan, Vikram Kumar, Vipin Dhyani, Shanti Mehra, Ayush Tripathi, Devendra Nene, Avinash Kumar Agarwal
Summary: This study assesses the technical feasibility of using DME as an alternative to diesel fuel and simulates the combustion process of a DME-fueled engine using computational fluid dynamics. The results suggest that DME exhibits faster evaporation and lower turbulence kinetic energy, leading to more efficient combustion and reduced heat transfer to the cylinder walls.
Article
Environmental Sciences
Ke Sun, Chang Huang, Dailong Shi, Guoxiang Li, Haiyang Zhao, Shuzhan Bai
Summary: A method is proposed to accurately evaluate the gas velocity and NH3 distribution uniformity at the front end of Urea-SCR carriers. The method is validated through simulation and experimental tests, and proves to accurately evaluate the uniformity of gas velocity and NH3 distribution, providing a reference for the study of front-end gas velocity and NH3 distribution of Urea-SCR carriers for diesel engines.
FRESENIUS ENVIRONMENTAL BULLETIN
(2022)
Article
Environmental Sciences
Praveena Vedagiri, Leenus Jesu Martin, Edwin Geo Varuvel
Summary: The use of biodiesel in diesel engines reduces HC, CO, and smoke emissions but increases NOx emissions. The implementation of Bharat Stage VI in India has pressured automobile manufacturers to include after treatment technology, such as SCR using urea solution as a reductant. Various parameters like exhaust gas temperature, injection angle, and SCR geometry greatly influence the NOx conversion efficiency. The impact of these parameters on different SCR designs has been investigated to determine the optimum design.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2021)
Article
Energy & Fuels
Byeong Gyu Jeong, Kwang Chul Oh, Seong Uk Jang
Summary: This study investigated the melting characteristics of a frozen urea water solution in relation to the surrounding heating module, observing differences in melting shapes based on the level of urea solution in the tank. The shape change was attributed to the formation of internal gaseous space during melting and the heat transfer characteristics of the fluid and solid substances.
Article
Engineering, Environmental
Na Zhu, Yulong Shan, Wenpo Shan, Zhihua Lian, Jinpeng Du, Hong He
Summary: Cu-SSZ-39 shows excellent hydrothermal stability and is expected to be used for NOx purification in diesel vehicles. The presence of NO2 can improve the NOx conversion of Cu-SSZ-39, especially for catalysts with low Cu loadings. The kinetic studies reveal that NO2 can promote the SCR reaction over Cu-SSZ-39 by facilitating the formation of surface nitrate species.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Chemical
Avik Denra, Nosir Matyakubov, Shirjana Saud, Sosiawati Teke, Duc Ba Nguyen, Young Sun Mok
Summary: This study investigated the use of gliding arc plasma and Ag/γ-Al2O3 catalyst to improve the removal efficiency of NOx from diesel engine exhaust gas. The experimental results showed that plasma treatment significantly enhanced the removal efficiency of NOx, especially at temperatures ranging from 127°C to 226°C. This enhancement was attributed to the reactivation of the catalyst and the production of hydrogen by the plasma.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Energy & Fuels
Chongpyo Cho, Yongjin Jung, Youngjin Shin, Youngdug Pyo, Jinyoung Jang, Youngmin Woo, Ahyun Ko, Gangchul Kim, Gyubaek Cho
Summary: The study investigated the reduction of nitrogen oxides (NOx) and N2O emissions with the selective catalytic oxidation (SCO) of an ammonia oxidation catalyst (AOC) in a urea-SCR system. Results showed that under certain operating conditions, undesirable reactions could lead to excess N2O emissions in V2O5/TiO2-based urea-SCR, while the AOC with Pt metal increased the emissions of NO, NO2, and N2O through NH3 oxidation.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2022)
Review
Engineering, Environmental
Rongrong Gui, Qinghua Yan, Tianshan Xue, Yanshan Gao, Yuran Li, Tingyu Zhu, Qiang Wang
Summary: Developing stable SCR catalysts for nitrogen oxides (NOx) abatement remains a challenge due to the complexity and uncertainty of actual flue gas emissions. Water vapor, present in actual flue gas, has been found to impact the de-NOx activity of SCR catalysts. This review focuses on the effects of water vapor on SCR catalysts, including promoting and inhibiting effects, as well as the mechanisms involved. The review also discusses strategies for developing water-resistant SCR catalysts.
JOURNAL OF HAZARDOUS MATERIALS
(2022)
Article
Energy & Fuels
Hassan Raza, Kwang-Chul Oh, Hongsuk Kim
Summary: This study investigates the N2O emission formation from heavy-duty diesel engine by injecting ammonia gas and urea water solution (UWS) in Cu-zeolite SCR. It was found that ammonia gas injection produced higher tailpipe N2O compared to UWS injection, especially during the cold and hot startup phases. Meanwhile, injecting ammonia gas can reduce the emissions of NO and NO2. Higher NH3/NOx ratio leads to increased N2O emissions and decreased NO and NO2 emissions. The concentration of N2O formation is high at an exhaust gas temperature of 200-250°C.
Review
Chemistry, Multidisciplinary
Ioannis Yentekakis, Amvrosios G. Georgiadis, Catherine Drosou, Nikolaos D. Charisiou, Maria A. Goula
Summary: This paper reviews the SCR process of NOx on perovskite-based catalysts, focusing on the impact of different reducing agents and perovskite compositions. The correlation between physicochemical properties of the catalysts and their deNO(x) activity is also discussed. Proposed kinetic models provide insights into deNO(x) mechanisms and potential improvements in deNO(x) efficiency.
Article
Green & Sustainable Science & Technology
Rafal Rogoz, Lukasz Jan Kapusta, Jakub Bachanek, Joseph Vankan, Andrzej Teodorczyk
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2020)
Article
Thermodynamics
Lukasz Jan Kapusta, Chen Shuang, Marcus Alden, Zhongshan Li
Article
Energy & Fuels
Niranjan Miganakallu, Zhuyong Yang, Rafal Rogoz, Lukasz Jan Kapusta, Cord Christensen, Sam Barros, Jeffrey Naber
Article
Energy & Fuels
Konrad Malik, Mateusz Zbikowski, Andrzej Teodorczyk
Article
Energy & Fuels
Wojciech Rudy, Andrzej Teodorczyk
Summary: The study conducted numerical simulations of deflagration to detonation transition (DDT) in hydrogen-air mixtures using ddtFoam code, showing that the simulated hydrogen concentration limits for DDT are close to experimental values, but depend on the spacing of obstacles.
Article
Energy & Fuels
Lukasz Jan Kapusta, Lukasz Boruc, Jan Kindracki
Summary: This study investigated the effect of fuel temperature and environmental pressure on the hypergolic ignition delay of triglyme with the addition of sodium borohydride and hydrogen peroxide. The tests were done under full matrix conditions, revealing the significant influence of both fuel temperature and environmental pressure on ignition delay.
Article
Engineering, Multidisciplinary
Michal Matuszczak, Mateusz Zbikowski, Andrzej Teodorczyk
Summary: This article introduces an approach based on deep learning and machine learning models for predicting turbine engine failures as an improvement of the condition-based maintenance scheme, while reviewing existing prognostics methods in the aviation industry. The study proposes a degradation scale for components and combines collected condition data with engine sensors and environmental data to train models. Use of data manipulation techniques and Bayesian optimization helps in identifying the best performing model for predicting component condition.
EKSPLOATACJA I NIEZAWODNOSC-MAINTENANCE AND RELIABILITY
(2021)
Article
Energy & Fuels
Wojciech Rudy, Andrzej Pekalski, Dmitriy Makarov, Andrzej Teodorczyk, Vladimir Molkov
Summary: The multi-phenomena deflagration model was used to simulate combustion of various fuel-air mixtures in different scale closed vessels in this paper. Key mechanisms affecting flame front propagation were studied, including the dependence of laminar burning velocity on concentration, pressure, and temperature, as well as the effects of preferential diffusion and turbulence.
Article
Energy & Fuels
Dariusz Kozak, Pawel Mazuro, Andrzej Teodorczyk
Summary: The modern internal combustion engine must meet various requirements, including reliability, reduced emission of pollutant gases, low maintenance, and efficiency at both low-load and high-load operating conditions. The use of a variable turbine geometry turbocharger significantly enhances efficiency of a two-stage turbine system, with highest efficiency achieved at 60,000 rpm and 11 degrees VTG position.
Article
Energy & Fuels
Lukasz Jan Kapusta, Jakub Bachanek, Changzhao Jiang, Jakub Piaszyk, Hongming Xu, Miroslaw Lech Wyszynski
Summary: This study aimed to investigate the influence of flash-boiling conditions on liquid propane sprays formed by a multi-hole injector at various injection pressures. The results showed that despite very different spray behaviours in the subcooled and flash-boiling regimes, the influence of injection pressure on propane sprays in terms of spray-tip penetration and spray angle is very similar for both conditions. The numerical model used did not properly simulate the flashing sprays and the spray collapse, making it more suitable for less superheated sprays.
Article
Thermodynamics
Rafal Rogoz, Niranjan Miganakallu, Zhuyong Yang, Jeffrey D. Naber, Lukasz Jan Kapusta
Summary: Combustion knock is a key factor limiting the performance of spark-ignition engines. Most previous studies focused on the influence of knock suppression methods on engine parameters, while neglecting the changes in knock probability distribution. This study analyzed the effects of co-injected additives on the probability distribution of knock and found slight but systematic changes in distribution skewness and kurtosis.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Engineering, Multidisciplinary
Lukasz Jan Kapusta, Rafal Rogoz, Jakub Bachanek
Summary: This study applied flash boiling to low-pressure injection of a urea-water solution (UWS) and investigated its influence on the selective catalytic reduction (SCR) system performance through numerical simulations. The research found that flash boiling can improve the performance of SCR systems, but directly increasing the temperature of UWS may have the opposite effect.
ATOMIZATION AND SPRAYS
(2021)