Article
Chemistry, Applied
Lin Li, Shuai Tong, Lunbo Duan, Changsui Zhao, Zhipeng Shi
Summary: By comparing chars produced under different atmospheres, it was found that the pore structure and specific surface area of chars are significantly affected by the gasification environment, while the presence of chemical groups has a minor impact on the chars. The best gasification reactivities were obtained on the chars produced under 50%CO2/50%N2 and 50%H2O/50%N2 atmospheres, largely influenced by the porosity of the chars.
FUEL PROCESSING TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Yingyue Teng, Xiaoting Bian, Yinmin Song, Bingzhi Wang, Na Li, Runxia He, Yunfei Wang, Quansheng Liu
Summary: This study investigated the effect of the iron component on the microcrystalline structure transformation properties of lignite during pyrolysis. The results showed that the iron component promoted the generation of CO2, CO, and H2 in the low-temperature stage and inhibited the formation of CO and H2 in the high-temperature stage. The iron component also inhibited the formation of CH4 throughout the pyrolysis process. Moreover, it restricted the spatial arrangement of aromatic rings and inhibited the formation of large aromatic rings (≥6 rings).
Article
Engineering, Chemical
Rui Zhang, Shuaiqi Zhao, Chengzhen Sun, Hui Jin, Kunpeng Zhao, Bofeng Bai
Summary: This study investigates the morphology evolution of lignite particles during supercritical water gasification, and finds that the sharpness of the particles has a significant impact on the gasification efficiency. The presence of high-sharpness structures promotes a particle conversion rate of up to 86.21%. Additionally, an optimized particle morphology of C-s < 0.74 and size D-0 < 1.5 mm achieves an average mass conversion rate of approximately 79.12% without the use of a catalyst.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Chenghao Luo, Dan Li, Long Huang, Zean Wang, Jian Zhang, Hao Liu, Zhaohui Liu
Summary: This study focuses on improving the combustion properties of graphite using potassium catalysts to lower the ignition temperature and promote combustion. Potassium and oxygen additives are found to reduce the activation energy required for oxidation reactions, enhancing graphite combustion efficiency.
Article
Chemistry, Physical
Athanasios Lampropoulos, Vassilios Binas, Michalis Konsolakis, George E. Marnellos
Summary: The study investigated the steam gasification reactivity of Greek lignite and its derived chars, finding that chars obtained after thermal treatment had the highest syngas yield and the H2/CO ratio could be adjusted for various downstream processes by co-feeding CO2 and H2O.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Applied
Xiongchao Lin, Changlun Li, Xin He, Jinze Dai, Deping Xu, Yonggang Wang
Summary: The study demonstrates that organically-bonded Ca2+ can more effectively improve the CO2 gasification rate of coal char, showing a more significant catalytic effect compared to CaO. Organic calcium can alter the electron distribution of aromatic macromolecules in char, promoting gasification reactions and enhancing reaction rates.
FUEL PROCESSING TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Jiaqi Yu, Di Sha
Summary: The study investigated the combustion kinetic characteristics of semi-coking dust during the early pyrolysis stage of lignite combustion explosion. The experimental results showed significant changes in the combustion characteristics of semi-coking dust with increasing pyrolysis temperature. The research findings provide valuable insights for understanding the mechanism of coal dust explosion and developing explosion suppression technology.
Article
Energy & Fuels
Boyang Bai, Luyao Qiang, Suisui Zhang, Hang Mu, Xiaoxun Ma
Summary: This study investigates the relationship between the structure and pyrolysis characteristics of coal. By artificially changing the structure of Shengli lignite using hydro-thermal pretreatment and solvent swelling pretreatment, the impact on physicochemical structure and pyrolysis characteristics was analyzed. The results show that hydro-thermal pretreatment removes oxygen-containing functional groups and aliphatic side chains, promoting the release of aromatic compounds. Solvent swelling pretreatment weakens the cross-linking structure, leading to increased tar production. This research provides a theoretical basis for the directional pyrolysis of lignite.
Article
Energy & Fuels
Jianan Qi, Cuigang Fan, Songgeng Li
Summary: The impacts of temperature and oxygen concentration on char structure evolution during pyrolysis were revealed using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and BET characterization techniques. Char prepared under oxygen atmosphere showed higher reactivity compared to that under inert (N2) atmosphere, with the presence of oxygen reducing char graphitization at high temperatures. The presence of oxygen in pyrolysis improved pore volume and specific surface area, with a critical oxygen concentration observed at high pyrolysis temperatures.
Article
Chemistry, Multidisciplinary
Ronnachai Tipo, Chatchawan Chaichana, Reiji Noda, Suparin Chaiklangmuang
Summary: The study investigated the effects of different treatments on lignite and the mechanism of Ni loading in coal, showing that treatment conditions altered the ash content and functional groups in coal, thereby influencing the ion exchange process of Ni. Different treatments resulted in the presence of Ni in different forms in the lignite char catalyst, with Ni contents ranging from 16.51-20.07 wt%.
Article
Agricultural Engineering
Dave D. Chun, Derek Ni, Amanda Simson
Summary: This study investigates the influence of feedstock selection on the quantity and quality of biochars produced from the pyrolysis of food waste and biowaste. The results show that the ash content of the feedstock plays a significant role in char yields and reactivity for CO2 gasification. Additionally, the addition of CO2 during pyrolysis has different effects on different feedstocks, highlighting the feedstock-specific nature of pyrolysis conditions. Overall, ash content and feedstock selection are important factors in determining the reactivity of biochars for gasification.
BIOMASS & BIOENERGY
(2022)
Article
Chemistry, Physical
Zhenyong Yin, Hao Xu, Yanpeng Chen, Tiantian Zhao, Jingjie Wu
Summary: Research on hydrogen production from coal gasification focuses on the formation of CO and H2 from coal and water vapor. Pure oxygen-steam gasification is used to improve gasification efficiency. The two-step gasification process involving coal pyrolysis and char gasification is an efficient method for hydrogen production.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Energy & Fuels
Rafal Morga, Barbara Bielowicz
Summary: This study characterizes and compares the microstructural features of different morphotypes in coal char obtained through gasification, revealing similarities and differences in their microstructural properties. Optical microscopy and Raman spectroscopy were used for analysis.
Article
Thermodynamics
Ruochen Wu, Jacob Beutler, Larry L. Baxter
Summary: This investigation examines the trends in biomass char diameter during gasification using continuous particle size data and a theoretical model to describe the variations. The model captures the qualitative and most of the quantitative variation in the data.
Article
Green & Sustainable Science & Technology
Remi Demol, Anthony Dufour, Yann Rogaume, Guillain Mauviel
Summary: This study evaluates the production of purified H2, heat and biochar from woodchips through pyrogasification processes. Techno-economic and life cycle assessments were conducted, and it was found that the market prices of hydrogen, heat, and biochar were not sufficient for profitability. The environmental benefits of pyrogasification processes were evaluated, showing advantages in terms of global warming and fossil fuel consumption potentials, but disadvantages in acidification potential and photochemical oxidant formation compared to SMR.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Engineering, Chemical
Ri Zhang, Shasha Zhang, Mengyan Ding
Summary: A thin liquid film method is proposed to evaluate sand erosion in annular flow. This method considers the direct interaction between the liquid film and gas core, as well as the entrainment and deposition of droplets. The erosion rate is calculated by considering the effects of liquid entrainment and particle velocity decay. The method is fully verified by comparing with experimental data.
Article
Engineering, Chemical
Yu Suo, Xianheng Su, Wenyuan He, Xiaofei Fu, Zhejun Pan
Summary: This research investigates the mechanical properties of sandstone-shale composite through orthogonal experimental method and discrete element simulation. The results show that different lithologies and thickness ratios can affect the strength and fracture mode of the composite rock samples.
Article
Engineering, Chemical
Maurizio Troiano, Andrea El Hassanin, Roberto Solimene, Alessia Teresa Silvestri, Fabrizio Scala, Antonino Squillace, Piero Salatino
Summary: This study investigates the potential of Fluidized Bed Finishing (FBF) for square flat AlSi10Mg specimens manufactured via Laser-Powder Bed Fusion (L-PBF) additive manufacturing technology. The results show that good finishing can be achieved using rotation-assisted tests, with a maximum reduction of surface roughness by 67%. Steel particles are found to be the most effective bed material.
Review
Engineering, Chemical
Ningbo Song, Wanzhong Yin, Jin Yao
Summary: Seawater's dissolved salts and minerals have various effects on the flotation process, including influencing the characteristics and behavior of flotation factors, as well as affecting the surface of sulfide minerals. In most cases, seawater has adverse effects on the flotation of sulfide minerals, but these effects can be mitigated by adjusting the reagents.
Article
Engineering, Chemical
Kaiqiao Wu, Shuxian Jiang, Victor Francia, Marc-Olivier Coppens
Summary: In rectangular and cylindrical annular fluidized beds, pulsating gas flow can create regular bubble patterns, overcoming challenges seen in conventional units. This study provides new opportunities for modularization of fluidized bed operations.
Article
Engineering, Chemical
Shuo Li, Huili Zhang, Jan Baeyens, Miao Yang, Zehao Li, Yimin Deng
Summary: The paper assesses the behavior of cohesive Geldart C-type particles when fluidized by air with the aid of vibration. It determines that mechanical vibration is a simple and effective method to improve the fluidity of cohesive particles during fluidization.
Article
Engineering, Chemical
Zhenfei Feng, Qingyuan Zhang, Shanpan Liang, Zhenzhou Li, Fangwen Guo, Jinxin Zhang, Ding Yuan
Summary: A new micro/mini-channel heat sink (MCHS) with a combined structure of longitudinal and transverse vortex generators is designed, using Al2O3 nanofluid as the working medium. The study explores the effects of transverse vortex generator shape and longitudinal vortex generator angle on the hydraulic and thermal characteristics, comprehensive performance, entropy generation, and exergy efficiency. The results show that the triangular transverse vortex generator improves the comprehensive performance and exergy efficiency. Combined with the longitudinal vortex generator, the MCHS achieves the best comprehensive performance, entropy generation, and exergy efficiency when the Reynolds number is 742.
Article
Engineering, Chemical
Kostas Giannis, Christoph Thon, Guoqing Yang, Arno Kwade, Carsten Schilde
Summary: This study presents a 3D convolutional neural network (3D-CNN) methodology for generating realistic 3D models of particles. The method trains on 2D projections of particle images to predict their 3D shapes, and evaluates the accuracy of the predictions using Fourier shape descriptors (FSDs). This methodology has wide applications in particle shape analysis.
Article
Engineering, Chemical
Zheng-qing Zhou, Lu-jia Chai, Yu-long Zhang, Ya-bin Wang, Ze-chen Du, Tian-yi Wang, Yu-zhe Liu
Summary: The dynamic oxidation and shell-breaking processes of aluminum nanoparticles (ANPs) during heating were studied using in situ transmission electron microscopy. The results revealed that the changes in shell thickness can be divided into three stages, and the active aluminum content of ANP decreased before shell-breaking.
Article
Engineering, Chemical
Fulei Chen, Huaqing Ma, Zihan Liu, Lianyong Zhou, Yongzhi Zhao
Summary: A particle breakage model based on the particle replacement scheme, using the polyhedral model to describe particles, is proposed in this work to accurately describe the breakage of a large number of particles. Additionally, a fast-cutting algorithm is proposed to reproduce the size distribution of progeny particles determined by the breakage model. The validation and simulation results show satisfactory accuracy, efficiency, and stability of the algorithm.
Review
Engineering, Chemical
Matteo Errigo, Christopher Windows-Yule, Massimiliano Materazzi, Dominik Werner, Paola Lettieri
Summary: Gas-solid fluidized-bed systems have advantages in terms of chemical reaction efficiency and temperature control, making them widely used in industrial applications. However, the design, scale-up, and optimization of these complex units are limited by the lack of deep physical understanding. Non-invasive and non-intrusive diagnostic techniques provide a way for researchers to study these systems without affecting the flow field or directly contacting the medium under study.
Article
Engineering, Chemical
Saeed Fateh, Mohammad Behshad Shafii, Mohammad Najafi, Cyrus Aghanajafi
Summary: Applying a magnetic field to ferrofluids alters their flow characteristics and enhances heat transfer. Through visualization and quantitative investigation, it is found that the magnetic field influences the flow patterns and velocity profiles, improving fluid mixing and vorticity magnitude.
Article
Engineering, Chemical
Lei Gao, Bingbing Wei, Xiaochuan Hu, Zaifeng Yao, Yiwen Fang, Xuejian Gao
Summary: In this study, a numerical model of sand triaxial test was established using discrete element software PFC3D, and an indoor triaxial test was conducted to calibrate the numerical model. The influence of microscopic parameters on the macroscopic mechanical response of sand was analyzed. The results showed that the friction coefficient had the greatest impact on the peak strength and residual strength of the sand's stress-strain curve, and it was positively correlated. The normal tangential stiffness ratio was negatively correlated, while the porosity and boundary flexibility stiffness had minimal influence on it.
Article
Engineering, Chemical
Xuan Liu, Jie Gong, Kai Jiang, Xiaojuan Lai, Yu Tian, Kang Zhang
Summary: This study aimed to improve the performance of lignite coal water slurries (CWSs) by synthesizing a series of three-arm amphiphilic block copolymers. By controlling the relative molecular weight, hydrophilic/hydrophobic ratio, and ionic group content, the apparent viscosity of CWSs was significantly reduced and the static stability was improved. Thermogravimetric testing and XPS analysis were conducted to reveal the mechanism behind the improved performance.
Article
Engineering, Chemical
Lanka Dinushke Weerasiri, Daniel Fabijanic, Subrat Das
Summary: Fluidization at low pressure offers significant benefits for the fine chemical industry. This study investigates the behavior of bubbles and bed expansion under low pressure conditions. It is found that lower pressure leads to larger bubbles, increased bubble quantity, and higher aspect ratio. The predictability is affected by the inhomogeneous fluidization, but low pressure fluidization can generate similar bubble sizes with lower fluidizing mass compared to atmospheric pressure.