Article
Energy & Fuels
Elmeri Pienihakkinen, Christian Lindfors, Taina Ohra-aho, Juha Lehtonen, Tom Granstrom, Minna Yamamoto, Anja Oasmaa
Summary: This study investigated fast pyrolysis of hydrolysis lignin in fluidized bed units, identifying technical challenges related to lignin degradation rates, secondary reactions in the vapor phase, pressure buildup, and deposit formation. The carbohydrate content of hydrolysis lignin was found to impact processability, with lower carbohydrate content leading to more challenges such as clogging and bed agglomeration. Solutions such as adding a rotating mixer or feeding raw material in different sections of the reactor were proposed to overcome these challenges.
Article
Biochemistry & Molecular Biology
Gary Reineccius, Shardul Patil, Vaidhyanathan Anantharamkrishnan
Summary: This research compares granulation to spray drying/agglomeration for producing flavoring particles. The study finds that granulation produces better properties, such as improved oxidation resistance, higher density, without the need for a two-step process.
Article
Engineering, Chemical
Eric Otto, Robert Duerr, Gerd Strenzke, Stefan Palis, Andreas Bueck, Evangelos Tsotsas, Achim Kienle
Summary: Fluidized bed spray agglomeration is a significant industrial particle formation process, and mathematical process modeling plays a crucial role in analyzing mechanistic processes, intensification, and control. This study focuses on the influence of seven operational parameters on particle size distribution and introduces a general method for obtaining a quantitative formulation of the dependency between agglomeration rate and process conditions.
ADVANCED POWDER TECHNOLOGY
(2021)
Article
Energy & Fuels
T. Leffler, M. Eriksson, B. Leckner, F. Lind, F. Winquist, P. Knutsson
Summary: The thermal conversion of biomass fuel mixes in fluidized beds can cause agglomeration. To counteract agglomeration, bed material is gradually exchanged with virgin bed material, and this results in increased disposal of used bed material. Furthermore, the bed material exchange represents a costly option, as it involves a cost for virgin bed material, for landfill, and for unplanned downtime of the plant. This paper presents a novel method for the evaluation of bed material quality: the electronic tongue (ET). Evaluation of bed material quality can contribute toward decreasing the cost of unnecessary exchanges of bed material. The proposed method was tested on bed material sampled on an almost daily basis from a commercial fluidized bed boiler during several months of operation. A two-electrode ET was used for the evaluation of the bed material quality. The analysis relied on pulsed voltammetry measurements and multivariate data analysis with Principal Component Analysis (PCA). The results suggest that it is possible to follow bed material changes and that the ET, after further development, may be used to optimize the material flows connected to the bed material. Further research is being conducted to optimize the ET's performance and its application in monitoring bed material.
Article
Biochemistry & Molecular Biology
D. Lee, B. Yoo
Summary: This study investigated the effects of adding maltodextrin during agglomeration on the physical, rheological, and structural properties of different types of water-soluble cellulose gums. The results showed that different cellulose gums exhibited varying flowability and cohesiveness in the presence of MD, and the concentration of MD influenced their porosity and dynamic moduli.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2021)
Review
Engineering, Chemical
Raul Favaro Nascimento, Mariana Ferreira Avila, Osvaldir Pereira Taranto, Louise Emy Kurozawa
Summary: This study conducted a bibliometric analysis to examine the global panorama and trends in agglomeration in a fluidized bed over the past four decades. China, Sweden, Germany, Canada, and the United States were identified as the most productive countries in terms of publications. Keyword analysis revealed the importance of fluidization, biomass, granulation, defluidization, and coating in agglomeration in fluidized beds. The study also found that the main focuses of publications were granulation and combustion, and research emphasis is progressing towards evaluating operating parameters and measurement techniques to enhance theoretical approaches in agglomeration in fluidized beds.
Article
Energy & Fuels
Ramin Khodabandehlou, Dominik Kirschenmann, Ronny Schimpke, Andreas Richter, Massoud Massoudi Farid, Hamid Reza Norouzi, Stefan Guhl, Afsanehsadat Larimi, Navid Mostoufi
Summary: This study investigates ash agglomeration as a potential problem in fluidized bed gasifiers. The results show that the defluidization temperature for ash agglomeration increases with the gas velocity, but remains constant after a certain fluidization number.
Article
Energy & Fuels
Robin Faust, Panida Aonsamang, Jelena Maric, Alyona Tormachen, Martin Seemann, Pavleta Knutsson
Summary: Thermal conversion of automotive shredder residue (ASR) using indirect fluidized bed gasification was conducted, with a focus on the interactions between the bed material and the ASR ash. Iron deposition onto olivine particles was observed, potentially increasing their oxygen-carrying ability. A significant portion of the particles in the bed originated from the ASR ash, containing Fe, Si, Zn, Ti, Cu, with some particles exhibiting a hollow morphology suggesting a melt state during formation.
Article
Energy & Fuels
Wenran Gao, Mingming Zhang, Hongwei Wu
Summary: This study investigates bed agglomeration during fast pyrolysis of bio-oil derived fuels in a fluidized-bed reactor and reveals the positive effects of methanol and biochar in reducing tar formation. The results show a positive linear correlation between agglomeration yield and tar formation, indicating the significant impact of tar formation on bed agglomeration of bio-oil derived fuels.
Article
Polymer Science
Donghyeon Lee, Byoungseung Yoo
Summary: Xanthan gum powder was agglomerated using a fluidized-bed agglomeration process with water and maltodextrin binder solution. The particle size gradually increased during agglomeration, and using maltodextrin as a binder resulted in larger particles. The rheological properties of the final product depended on the binder solution used. The native xanthan gum powder had small and dense particles, while the agglomerates had larger and porous particles with rough surfaces.
Review
Chemistry, Physical
Francisco Regis Machado Nascimento, Aldemar Martinez Gonzalez, Electo Eduardo Silva Lora, Albert Ratner, Jose Carlos Escobar Palacio, Rafaela Reinaldo
Summary: Thermochemical conversion through gasification is an important technology for energy recovery from solid fuel, with higher conversion efficiency than combustion and pyrolysis. The most common technologies for this conversion involve fluidized bed or bubbling fluidized bed systems, operating at isothermal temperatures to promote chemical reactions and gas-solid contact. High gasification temperatures improve carbon conversion efficiency but may increase the risk of bed agglomeration, especially with alkali-rich biomasses.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Energy & Fuels
Burak Ulusoy, Bozidar Anicic, Liyan Zhao, Weigang Lin, Bona Lu, Wei Wang, Kim Dam-Johansen, Hao Wu
Summary: Different additives were employed to reduce NOX emissions and bed agglomeration in fluidized bed combustion of biomass. Some additives prevented bed agglomeration and reduced the conversion of fuel-N to NO, but led to higher N2O emissions. Air staging and introduction methods of additives had varying effects on NOX emissions and bed agglomeration.
Article
Thermodynamics
Jong-Woo Kim, Yong-Seong Jeong, Joo-Sik Kim
Summary: This study investigated the two-stage air gasification of wood pellets using active carbon as a catalyst. The results showed that smooth gasification could be achieved at around 600 degrees C, producing a producer gas with a similar gas quality to high-temperature gasification. Active carbon demonstrated excellent performance in removing tar and increasing H2 production.
Article
Thermodynamics
Zhuo Liu, Jianbo Li, Xiaofei Long, Xiaofeng Lu
Summary: This paper characterizes the bed particles and agglomerates formed during Zhundong lignite combustion in a circulating fluidized bed (CFB) to study the role of Na and ash-bed interaction in agglomeration. Experimental results show that discrete quartz particles are coated with submicron ash particles enriched in Ca and Mg. Na silicates are locally enriched between quartz particles and initiate agglomeration. The agglomeration is initiated at a relatively low melting-point of 950-1100 ? when Na silicates and coated ashes become soft or melt. When steel slag is used as the bed material, Na in bottom ash becomes negligible, and no ash coating layer is formed, mitigating agglomeration.
Article
Engineering, Environmental
Wei Zhang, Haiming Wang, Changfu You
Summary: A coupled methodology was developed to model the fluidized bed coating process considering particle abrasion. Experimental data was used to verify the models of evaporation, coating, and abrasion. The research provides an efficient approach for modeling fluidized bed coating processes and offers guidelines for practical application of in-situ desulfurizer preparation.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Applied
Andreas Eschenbacher, Jakob Afzali Andersen, Anker Degn Jensen
Summary: The study investigated the catalytic vapor phase upgrading of acetol over different microporous and mesoporous HZSM-5 catalysts. Increasing temperature led to higher gas yield, lower coke yield, increased acetol conversion, and higher selectivities to oxygen-free hydrocarbons. The catalyst characteristics played a role in the reaction outcomes.
Article
Chemistry, Physical
Niels D. Nielsen, Anker D. Jensen, Jakob M. Christensen
Summary: Experiments showed that CO2 is more favorable for methanol synthesis on Cu catalyst compared to CO. At low conversion conditions, CO has inhibiting effects, but as conversion is increased, a beneficial role of CO is observed. CO's beneficial role mainly comes from its promotion of the water-gas shift reaction, which helps to reduce the inhibitory effect of water on Cu-based catalysts.
JOURNAL OF CATALYSIS
(2021)
Article
Energy & Fuels
Andreas Eschenbacher, Trond Myrstad, Niels Bech, Hang Dao Thi, Milos Auersvald, Kevin M. Van Geem, Anker D. Jensen
Summary: This study investigated the blending of two bio-oils obtained from different catalytic treatments of wheat-straw pyrolysis vapors with atmospheric residue, showing the impact of varying levels of basic nitrogen and aromatics on FCC performance. Refinery operators interested in co-processing fossil oils and biomass-derived pyrolysis oils with elevated content of nitrogen and aromatics can benefit from the important information provided in this study.
Review
Chemistry, Physical
Joachim Thrane, Uffe V. Mentzel, Max Thorhauge, Martin Hoj, Anker D. Jensen
Summary: This paper provides an overview of efforts to find alternative catalysts for the Formox process and critically assess these alternatives for their industrial potential. The results suggest the possibility of finding catalysts with longer lifetimes and higher efficiency.
Article
Chemistry, Physical
J. A. Andersen, J. M. Christensen, M. ostberg, A. Bogaerts, A. D. Jensen
Summary: This study investigated the plasma-catalytic ammonia decomposition for producing hydrogen using a packed-bed dielectric barrier discharge reactor. The introduction of dielectric materials with certain dielectric constants improved the ammonia decomposition, with MgAl2O4 showing the highest conversion rate. Further studies are needed to optimize the efficiency of this technology.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Engineering, Chemical
Frederik Zafiryadis, Anker Degn Jensen, Weigang Lin, Elisabeth Akoh Hove, Morten Boberg Larsen, Hao Wu
Summary: This study utilizes the Eulerian-Lagrangian multiphase particle-in-cell method to simulate the injection of a gas-liquid spray into a gas-solid fluidized bed. The model accurately predicts the gas temperature distribution within the injection region, but discrepancies may arise due to the presence of wet particle agglomerates in the spray region.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Chemistry, Physical
Max Schumann, Jan-Dierk Grunwaldt, Anker D. Jensen, Jakob M. Christensen
Summary: The Rh-catalyzed CO hydrogenation was studied using Rh/ZrO2 and Rh/SiO2 catalysts. The support effect was found to accelerate the CO dissociation on the metal surface. Additionally, a H-assisted mechanism of CO activation was revealed, and the high CO coverage was shown to be essential for the production of oxygenated products.
JOURNAL OF CATALYSIS
(2022)
Article
Engineering, Environmental
J. A. Andersen, M. C. Holm, K. van't Veer, J. M. Christensen, M. Ostberg, A. Bogaerts, A. D. Jensen
Summary: The study investigates the factors affecting ammonia synthesis in a dielectric barrier discharge reactor, using both experiments and a plasma kinetic model. The effects of plasma power, feed flow rate, N2:H2 feed ratio, gas residence time, temperature, and packing material were examined. The results show that increasing the feed flow rate and gas temperature with a packing material present in the plasma can enhance the ammonia synthesis rate.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Environmental
Frederik Zafiryadis, Anker Degn Jensen, Weigang Lin, Sonnik Clausen, Elisabeth Akoh Hove, Morten Boberg Larsen, Hao Wu
Summary: The cracking of sugars to glycolaldehyde and other oxygenates shows potential in lab-scale fluidized beds. This study adopts a gas-phase kinetics model and implements it into the Computational Particle Fluid Dynamics (CPFD) framework to simulate sugar cracking in a pilot-scale circulating fluidized bed riser. The results show good agreement with experimental data and suggest the need for more accurate predictions of product yields.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Chemical
J. A. Andersen, K. van't Veer, J. M. Christensen, M. Ostberg, A. Bogaerts, A. D. Jensen
Summary: The use of ammonia as a storage medium for hydrogen and its plasma-catalytic decomposition for retrieval of hydrogen are investigated. Experimental results show that increasing the specific energy input enhances the ammonia conversion. A kinetic model is used to analyze the decomposition mechanism, indicating that the collisions between NH3 and high-energy electrons initiate the decomposition.
CHEMICAL ENGINEERING SCIENCE
(2023)
Review
Engineering, Chemical
Frederik Zafiryadis, Anker Degn Jensen, Weigang Lin, Elisabeth Akoh Hove, Morten Boberg Larsen, Hao Wu
Summary: This paper provides a thorough and up-to-date review of experimental and numerical investigations of gas-liquid sprays into gas-solid fluidized beds. It presents a phenomenological description of the prevalent mechanisms of gas-liquid injection under different operating conditions and identifies suitable computational fluid dynamic models for simulating the mechanisms involved in gas-liquid-solid interactions, along with recommendations for future work.
Review
Chemistry, Physical
Hamed Baniamerian, Martin Hoj, Matthias Josef Beier, Anker Degn Jensen
Summary: This review discusses the attractive approaches of catalytic conversion of (ligno)cellulosic biomass for the production of valuable oxygenated chemicals and platform molecules under hydrothermal or pyrolysis conditions. To design the most effective catalysts and gain a better understanding of the processes, the main reactions and possible products obtained from cellulose catalytic valorization, specifically diols, are discussed. The review systematically summarizes recent advancements of heterogeneous catalysts and their structure-activity relationships for the selective production of diols from cellulose and cellulose-derived sugars under both pyrolysis and hydrothermal conditions.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Review
Engineering, Environmental
William Gundtorp, Thomas Klint Torp, Anker Degn Jensen
Summary: Due to convenience and toxicity, research on the catalytic oxidation of poly-chlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) is mainly conducted on model compounds instead of PCDD/Fs themselves. This raises questions about the validity of using model compounds to design catalysts for PCDD/F removal. A review of the literature on catalytic destruction of PCDD/Fs and model compounds indicates that their reaction kinetics are similar, but with some deviations in gas phase composition. It is found that V2O5/TiO2-based catalysts are the most studied and achieve higher catalytic activity compared to other non-precious metal catalysts.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Hamed Baniamerian, Martin Hoj, Matthias Josef Beier, Anker Degn Jensen
Summary: Hydrous pyrolysis of glucose is a promising method to produce glycolaldehyde and other valuable oxygenates. A pulsed chromatographic method was proposed to investigate the effect of operating parameters on the product distribution and glycolaldehyde yield. This technique provided insights into the reaction pathways and allowed for determination of the reaction time-frame and rate parameters.
REACTION CHEMISTRY & ENGINEERING
(2023)
Article
Energy & Fuels
Wenhao Hu, Zsuzsa Sarossy, Anker Degn Jensen, Anders Egede Daugaard, Peter Arendt Jensen
Summary: In this study, the pyrolysis of pure low density polyethylene was investigated using a lab-scale two-stage fixed-bed pyrolyzer. Different catalytic materials were used in the second reactor to upgrade the vapors. The results showed that the use of certain catalysts and higher temperatures can significantly decrease the chain length of hydrocarbons in the condensed product and convert the wax into a liquid.
