Article
Biotechnology & Applied Microbiology
Zuzana Vajglova, Narendra Kumar, Markus Peurla, Leena Hupa, Kirill Semikin, Dmitry A. Sladkovskiy, Dmitry Yu Murzin
Summary: Metal-acid bifunctional catalysts play a crucial role in various industrial chemical processes, such as hydroisomerization of n-hexane. This study investigated the deactivation and regeneration of metal-acid bifunctional extrudates during continuous n-hexane hydroisomerization in a fixed-bed reactor. The results showed that the location of the metal has a greater impact on catalyst deactivation than the metal-to-acid site ratio or site proximity. Decline in n-hexane conversion and selectivity to C-6 isomers were associated with changes in the textural properties and acidity of the deactivated catalyst.
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
(2021)
Article
Chemistry, Applied
Ye Yang, Lu Xu, Yuchao Lyu, Xinmei Liu, Zifeng Yan
Summary: Intergrowth zeolites combine advantages of single phases, with the SAPO-11/5 intergrowth zeolite showing intermediate surface acidity and pore volume by controlling the AFI/AEL ratio. The Ni/SAPO-11/5-2 bifunctional catalyst exhibits improved isomers selectivity and yield in n-hexane hydroisomerization, attributed to its unique pore structure and surface acidity.
MICROPOROUS AND MESOPOROUS MATERIALS
(2021)
Article
Energy & Fuels
Farzad Jokar, Seyed Mehdi Alavi, Mehran Rezaei
Summary: This study investigates the effect of pore shape on the hydroisomerization of n-pentane by synthesizing composites with different pore structures. The results demonstrate that a well-developed micro/mesoporous structure with higher specific surface area improves the yield and conversion, while a better balance between acidic and metallic sites enhances the RON of the product stream.
Article
Chemistry, Physical
Zuzana Vajglova, Paivi Maki-Arvela, Kari Eranen, Narendra Kumar, Markus Peurla, Dmitry Yu. Murzin
Summary: The study revealed that controlling the location of Ru in the catalyst can significantly impact activity and selectivity, while significant differences in product distribution were observed between batch and continuous experiments, highlighting the importance of Ru location and catalyst characteristics.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Physical
Karolina Jaroszewska, Monika Fedyna, Aleksandra Masalska, Rafal Luzny, Janusz Trawczynski
Summary: In this study, hierarchical AlSBA-15-zeolite materials were used as supports for hydroisomerization catalysts, with a focus on the effect of zeolite type and Pd addition. The Pt-Pd/AlSBA-15-β catalyst showed higher isomerization efficiency, leading to improved research octane number.
Article
Chemistry, Physical
M. Ibrahim, A. A. Jalil, W. F. W. Zakaria, N. A. A. Fatah, M. Y. S. Hamid, S. M. Izan, H. D. Setiabudi
Summary: The research indicated that increasing zirconium loading can enhance the Lewis acid sites of the catalyst, while excessive loading can reduce the amount of protonic acid sites, thus decreasing the catalytic performance.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Multidisciplinary
Xiaohui Gao, Yuting Bai, Hao Zhang, Xingyi Wang
Summary: Pt catalysts with different chemical states and structures were supported on CeO2 and investigated in catalytic oxidation reactions. The Pt/CeO2-SR catalyst exhibited high activity and stability in the oxidation of n-decane, while the Pt/CeO2-WI catalyst showed lower activity and stability. The adsorption of alkane molecules occurred through the interaction with Ce-OH, with weaker adsorption for C6H14 and C3H8 compared to n-decane.
Article
Chemistry, Physical
Christopher M. Lew, Cong-Yan Chen, Gary J. Long, Fernande Grandjean, Andrew S. Ichimura, Dan Xie, Nicolas A. Grosso-Giordano, Khetpakorn Chakarawet, Howard S. Lacheen, Kurt O. Jensen, Abraham Martinez, Alexander Katz, Bi-Zeng Zhan, Stacey I. Zones
Summary: The study compared the performance of Fe-SSZ-70 and Al-SSZ-70 in isomerization reactions, with Fe-SSZ-70 showing higher isomerization yield and selectivity due to its weaker acidity.
Article
Chemistry, Physical
Jean-Marc Schweitzer, Jerome Rey, Charles Bignaud, Tomas Bucko, Pascal Raybaud, Mailys Moscovici-Mirande, Frederic Portejoie, Christophe James, Christophe Bouchy, Celine Chizallet
Summary: In this study, a predictive multiscale single-event microkinetic model based on density functional theory (DFT) calculation was developed for the hydroconversion of n-heptane in large-pore zeolites. The model was validated by experimental kinetic data and showed satisfactory agreement. The results provide important insights into the catalytic performance of large-pore zeolites in alkane hydroconversion.
Article
Green & Sustainable Science & Technology
Witold Zukowski, Przemyslaw Migas, Marta Zurek, Jan Wrona
Summary: The results of the n-hexane oxidation process in a fluidized bed reactor with a catalytic bed are presented. Baffles were used to modify the flow in the reactor and improve the process efficiency. The best results were achieved with the use of horizontal elements in the form of grids, which significantly improved the conversion of n-hexane to carbon dioxide.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Engineering, Environmental
Mu He, Muhammad-Faryad Ali, Yue-Qin Song, Xiao-Long Zhou, Jin An Wang, Xin-Yao Nie, Zheng Wang
Summary: This study investigated the coke deactivation behavior of HZSM-5 zeolites with different Si/Al ratios in the n-hexane cracking reaction for 200 hours. The results showed that internal coke formed in the micropores of the zeolite initially and significantly inhibited catalytic activity, while external coke had a minor effect. The deactivation behavior differed between zeolites with low and high Si/Al ratios.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Physical
Zhen Jiang, Liduo Chen, Yanhong Cui, Huijie Gao, Yisi Zhou, Wei Zhang, Yanhua Suo, Yingjun Wang
Summary: n-Alkane hydroisomerization over bifunctional catalysts is an effective method for clean fuel production. In this study, a series of Pt/SAPO-11 catalysts with different Pt loading were synthesized and characterized. The catalytic performance of different Pt loading on Pt/SAPO-11 catalysts in n-heptane hydroisomerization was investigated. The results showed that the 0.5Pt/SAPO-11 catalyst exhibited higher selectivity and conversion towards isomers at 310 degrees C.
Article
Engineering, Chemical
Nebojsa Korica, Pedro S. F. Mendes, Jeriffa De Clercq, Joris W. Thybaut
Summary: The study found that the presence of methylcyclohexane affects the hydroconversion of n-octane over Pt/HUSY catalysts, but does not impact the behavior of methylcyclohexane itself. This is mainly due to the preferred adsorption of cycloalkanes on metal sites, leading to a shift from ideal to nonideal hydrocracking.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Energy & Fuels
Jiazheng Sun, Shuxiang Xiong, Hailong Lin, Qiong Wu, Linfei Xiao, Zhenni Liu, Xiujie Li, Wei Wang, Wei Wu
Summary: In this work, hierarchical ZSM-23 zeolites were synthesized using cationic surfactants and cationic polyelectrolytes as growth modifiers, and Pd/ZSM-23 catalysts were prepared. The addition of appropriate growth modifiers significantly improved the yield of iso-alkane products and limited the cracking process, with Pd/Z23-5PP catalyst showing the highest yield.
Article
Chemistry, Physical
Ye Yang, Xinmei Liu, Yuchao Lyu, Yuxiang Liu, Weilong Zhan, Zhumo Yu, Lei Fan, Zifeng Yan
Summary: A nickel-based bifunctional catalyst was developed with enhanced hydroisomerization performance using an in-situ solid synthesis method. By controlling the EDTA/Ni2+ ratio, highly dispersed Ni nanoparticles were achieved on SAPO-5, leading to improved performance in n-hexane hydroisomerization. These results provide a facile approach for the preparation of highly dispersed non-noble metal based bifunctional catalysts at a high loading.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Engineering, Environmental
Zuzana Vajglova, Marisa Navas, Paivi Maki-Arvela, Kari Eranen, Narendra Kumar, Markus Peurla, Dmitry Yu. Murzin
Summary: One-pot transformations of citral were investigated over Ru-catalysts in both batch and continuous modes. The study found that the Z/E-citral ratio decreased with increasing Ru particle size, and the Ru/H-Y-80 extrudates exhibited comparable catalytic behavior.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Energy & Fuels
Jan-Erik Eriksson, Maria Zevenhoven, Patrik Yrjas, Anders Brink, Leena Hupa
Summary: This study discusses the potential corrosion of boiler materials in chemical-looping combustion (CLC) of biomass. The results suggest that potassium-contaminated ilmenite may lead to minor corrosion of all studied materials under oxidizing conditions, while ferritic steels are prone to corrosion under reducing fuel reactor conditions in the presence of HCl and with KCl deposit. Austenitic and nickel-based alloys did not corrode under the test conditions.
Article
Chemistry, Physical
Somayeh Taghavi, Paivi Maki-Arvela, Zuzana Vajglova, Markus Peurla, Ilari Angervo, Kari Eranen, Elena Ghedini, Federica Menegazzo, Mojgan Zendehdel, Michela Signoretto, Dmitry Yu Murzin
Summary: Citronellal was converted to menthol using a Ni catalyst supported on H-Beta zeolite. The acidity and Ni loading of the catalyst significantly influenced the catalytic performance. The best results were obtained with a Ni loading of 15 wt.% on H-Beta-25, giving a yield of 36% menthols and 77% stereoselectivity. The catalyst could be successfully regenerated and reused with similar activity and selectivity.
Article
Thermodynamics
Roland Balint, Markus Engblom, Jonne Niemi, Daniel Lindberg, Timo Saarinen, Jaakko Rautala, Mikko Hupa, Leena Hupa
Summary: By analyzing superheater ash deposits from a kraft recovery boiler, the effects of two deposit ageing mechanisms were identified. Local differences in deposit morphology and chemical composition were observed under the electron microscope. The diffusion of alkali chloride vapours towards the steel due to temperature gradient was evident. The presented results provide a better understanding of intradepositional changes and help assess risks of deposit-related operational problems in the boiler.
Article
Energy & Fuels
Roland Balint, Markus Engblom, Emil Vainio, Tor Lauren, Jonne Niemi, Jaakko Rautala, Timo Saarinen, Mikko Hupa, Leena Hupa
Summary: Deposit samples of different exposure times were collected from a Finnish kraft recovery boiler. Analyzing the morphology and chemical composition of the deposits revealed differences due to varying deposition mechanisms. Increasing exposure time led to enrichment in Cl content, which occurred through diffusion of Cl-vapours from the flue gas. Two aging mechanisms were identified within the deposits, involving alkali chloride layers and sulfation. Analysis of melting temperature showed a higher risk of corrosion in the Cl and K-rich layer adjacent to the steel surface.
Article
Materials Science, Ceramics
Adrian Stiller, Markus Engblom, Oskar Karlstrom, Mika Linden, Leena Hupa
Summary: Bioactive glasses are effective grafting materials for bone tissue repair, but predicting their degradation behavior in vivo remains challenging. This study investigates the effect of flow rate on the dissolution behavior of bioactive glass S53P4. The findings demonstrate that flow rate significantly affects the glass dissolution rate, ion release, and reaction layer development, emphasizing the importance of dynamic dissolution tests.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
Saara Sirkia, Syeda Qudsia, Minna Siekkinen, Wolfgang Hoepfl, Tanja Budde, Jan-Henrik Smatt, Jouko Peltonen, Leena Hupa, Terhi J. Heino, Pekka K. Vallittu
Summary: This study aimed to characterize the physicochemical and biological properties of functionalized calcium carbonate (FCC) consisting of calcium carbonate particles with a hydroxyapatite layer. The results showed that FCC could adsorb calcium ions from the surrounding liquid, which should be carefully considered in cell culture assays.
Article
Materials Science, Ceramics
Minna Siekkinen, Oskar Karlstrom, Leena Hupa
Summary: This study expands the understanding of bioactive glass S53P4 dissolution by implementing a cascade reactor, and reveals the influence of released ions and decreased available hydrogen ions for ion exchange on the dissolution behavior.
Article
Energy & Fuels
Emil Vainio, Patrik Yrjas, Leena Hupa, Mikko Hupa
Summary: Optimizing energy recovery and efficient use of energy in flue gases is crucial for power plant economy. NH4Cl is highly corrosive on carbon steel and its corrosion is influenced by water vapor concentration, relative humidity, and temperature. Studying the hygroscopic and corrosive properties of NH4Cl can help prevent NH4Cl deposit build-up and corrosion.
Article
Energy & Fuels
J. -e. Eriksson, J. Lehmusto, M. Dirbeba, L. Silvander, D. Lindberg, L. Hupa
Summary: The study investigated the impact of small alkali halide additions on the melting behavior and corrosivity of a synthetic sulfate deposit at temperatures of 500, 550, and 600 degrees C. Three different alloyed commercial heat-transfer materials were studied. It was found that even small amounts of reactive alkali halides significantly changed the corrosion and melting behavior of the mixture.
Article
Engineering, Biomedical
Peter Uppstu, Simon Engblom, Saara Inkinen, Leena Hupa, Carl-Eric Wilen
Summary: The mechanical properties of polylactide stereocomplexes (PLA SC) have been studied through tensile testing, with inconsistent results. The compressive properties of PLA SC compared to homocrystalline or amorphous PLA remain poorly understood. This study investigates the mechanical and degradation properties of coated glass scaffolds with different types of PLA coatings before and after immersion in simulated body fluid.
JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS
(2023)
Article
Engineering, Chemical
Sara Benalia, Fiseha Tesfaye, Daniel Lindberg, Leena Hupa, Patrice Chartrand, Christian Robelin
Summary: A thermodynamic model has been developed for a mixed-phase salt system (including elements such as NaCl, Na2CO3, Na2SO4, Na2S2O7, Na2CrO4, Na2Cr2O7, Na2MoO4, Na2Mo2O7, Na2O, KCl, K2CO3, K2SO4, K2S2O7, K2CrO4, K2Cr2O7, K2MoO4, K2Mo2O7, and K2O) commonly involved in energy production. This model accurately predicts the properties and phase equilibria of solid deposits formed in steel and stainless steel installations containing alloying elements such as Ni, Cr, Mo, W, and V.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Energy & Fuels
Roland Balint, Markus Engblom, Jonne Niemi, Mikko Hupa, Leena Hupa
Summary: This study investigates the initial melting behavior of synthetic ash deposits and how it affects the final deposit morphology. The results show that the amount of melt formed during the experiment plays a crucial role in determining the deposit morphology. Two types of deposit morphologies, skeletal and molten, were identified, and their aging behaviors were found to differ. The findings provide important insights into the connection between deposit morphology and deposit aging.
Article
Chemistry, Multidisciplinary
Sara Benalia, Fiseha Tesfaye, Daniel Lindberg, David Sibarani, Leena Hupa, Patrice Chartrand, Christian Robelin
Summary: This paper evaluates crystallographic data and thermodynamic properties of various salts and provides a foundation for further research on high temperature corrosion.
JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA
(2023)
Article
Materials Science, Ceramics
Polina Sinitsyna, Markus Engblom, Leena Hupa
Summary: The impact of substituting K2O for Na2O on the physico-chemical and bioactive properties of bioactive glass S53P4 was studied. It was found that the substitution showed a mixed-alkali effect, with the optimal composition containing around 20% K2O. The thermal properties and ion release kinetics varied with the potassium content, providing insights for tailoring new bioactive glass compositions.