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| 1 | Experimental investigation of ash deposits on convection heating surfaces of a circulating fluidized bed municipal solid waste incinerator显示文摘Incineration of municipal solid waste(MSW) is a waste treatment method which can be sustainable in terms of waste volume reduction, as well as a source of renewable energy.During MSW combustion, increased formation of deposits on convection heating exchanger surfaces can pose severe operational problems, such as fouling, slagging and corrosion.These problems can cause lower heat transfer efficiency from the hot flue gas to the working fluid inside the tubes. A study was performed where experiments were carried out to examine the ash deposition characteristics in a full-scale MSW circulating fluidized bed(CFB) incinerator, using a newly designed deposit probe that was fitted with six thermocouples and four removable half rings. The influence of probe exposure time and probe surface temperature(500, 560, and 700℃) on ash deposit formation rate was investigated. The results indicate that the deposition mass and collection efficiency achieve a minimum at the probe surface temperature of 560℃. Ash particles are deposited on both the windward and leeward sides of the probe by impacting and thermophoretic/condensation behavior. The major inorganic elements present in the ash deposits are Ca,Al and Si. Compared to ash deposits formed on the leeward side of the probe,windward-side ash deposits contain relatively higher Ca and S concentrations, but lower levels of Al and Si. Among all cases at different surface temperatures, the differences in elemental composition of the ash deposits from the leeward side are insignificant.However, as the surface temperature increases, the concentrations of Al, Si, K and Na in the windward-side ash deposits increase, but the Ca concentration is reduced. Finally,governing mechanisms are proposed on the basis of the experimental data, such as deposit morphology, elemental composition and thermodynamic calculations. | Zhi Tang Xiaoping Chen Daoyin Liu Yaming Zhuang Minghua Ye Hongchan Sheng Shaojuan Xu | 2016 | Journal of Environmental Sciences2016，28，10： | 6 |
| 2 | Comparative study of two fluid model and dense discrete phase model for simulations of gas-solid hydrodynamics in circulating fluidized beds显示文摘Computational fluid dynamics(CFD)has become a valuable tool to study the complex gas-solid hydrodynamics in the circulating fluidized bed(CFB).Based on the two fluid model(TFM)under the Eulerian-Eulerian framework and the dense discrete phase model(DDPM)under the Eulerian-Lagrangian framework,this work conducts the comparative study of the gas-solid hydrodynamics in a CFB riser by these two different models.Results show that DDPM could be used to predict gas-solid hydrodynamics in the circulating fluidized bed,and there are differences between TFM and DDPM,especially in the radial distribution profiles of solid phase.Sensitivity analysis results show that the gas-solid drag model exhibits significant effects on the results for both the two models.The specularity coefficient and the restitution coefficient in the TFM,as well as the reflection coefficient and the parcel number in the DDPM,exhibit less impact on the simulated results. | Ying Wu Daoyin Liu Jinding Hu Jiliang Ma Xiaoping Chen | 2021 | Particuology2021，19，2： | 3 |
| 3 | Bubbling behavior of cohesive particles in a two-dimensional fluidized bed with immersed tubes显示文摘 | Jiliang Ma Daoyin Liu Xiaoping Chen | 2017 | Particuology2017，15，2： | 2 |
| 4 | Influence of cycle time distribution on coating uniformity of particles in a spray fluidized bed by using CFD-DEM simulations显示文摘Cycle Time Distribution(CTD)plays a critical role for determining uniformity of particle coating in spray fluidized beds.However,the CTD is influenced by both geometrical structure and operating conditions of fluidized bed.In this study,a spray fluidized bed of coating process is simulated by a comprehensive Computational Fluid Dynamics-Discrete Element Model(CFD-DEM).To achieve different behaviors of CTD,some modifications are designed on a pseudo-2D internally circulating fluidized bed,which traditionally composes of a high-velocity upward bed and low-velocity downward bed.These modifi-cations include making the air distributor slope and/or laying a baffle in the downward bed.First,the CTD and evolution of particle size distribution under different bed structures are compared.The CTD directly influences the coating uniformity.By making the particles flowing along a parallel direction in the downward bed through the geometrical modifications,the CTD becomes narrower and the coating uniformity is significantly improved.Second,under the optimized bed structure,the influence of oper-ating conditions on the coating uniformity is studied.Properly increasing the fluidization gas velocity and the fluidization gas temperature and reducing the liquid spray rate can improve the coating uniformity. | Heng Li Daoyin Liu Jiliang Ma Xiaoping Chen | 2023 | Particuology2023，，5： | 1 |
| 5 | Fly ash recirculation by bottom feeding on a circulating fluidized bed boiler co-burning coal sludge and coal显示文摘 | Lunbo Duan Daoyin Liu Xiaoping Chen Changsui Zhao | 2012 | Applied Energy2012，，： | 1 |
| 6 | Simu- lation of char and propane combustion in a fluidized bed by extending DEM-CFD approach显示文摘 | LIU Daoyin CHEN Xiaoping ZHOU Wu | 2011 | Proceedings of the Combustion Institute2011，33，2： | 1 |
| 7 | Simula- tion of char and propane combustion in a fluidized bed by extending DEM-CFD approach显示文摘 | Liu Daoyin Chen Xiaoping Zhou Wu | 2011 | Proceedings of the Combustion Institute2011，33，2： | 1 |
| 8 | Devel- opment and test of CFD-DEM model for complex ge- ometry: a coupling algorithm for Fluent and DEM 显示文摘 | LIU Daoyin BU Changsheng CHEN Xiaoping | 2013 | Computers & Chemical Engineering2013，58，11： | 1 |
| 9 | Ignition behavior of single coal particle in a fluidized bed under O2/CO2 and O2/N2atmospheres:A combination of visual image and particle temperature显示文摘 | Bu Changsheng Liu Daoyin Chen Xiaoping etc | 2014 | Applied Energy2014，115，30： | 1 |
| 10 | Modeling of single coal particle combustion in O_(2)/N_(2)and O_(2)/CO_(2)atmospheres under fluidized bed condition显示文摘A one-dimensional transient single coal particle combustion model was proposed to investigate the characteristics of single coal particle combustion in both O_(2)/N_(2)and O_(2)/CO_(2)atmospheres under the fluidized bed combustion condition.The model accounted for the fuel devolatilization,moisture evaporation,heterogeneous reaction as well as homogeneous reactions integrated with the heat and mass transfer from the fluidized bed environment to the coal particle.This model was validated by comparing the model prediction with the experimental results in the literature,and a satisfactory agreement between modeling and experiments proved the reliability of the model.The modeling results demonstrated that the carbon conversion rate of a single coal particle(diameter 6 to 8 mm)under fluidized bed conditions(bed temperature 1088 K)in an O_(2)/CO_(2)(30:70)atmosphere was promoted by the gasification reaction,which was considerably greater than that in the O_(2)/N_(2)(30:70)atmosphere.In addition,the surface and center temperatures of the particle evolved similarly,no matter it is under the O_(2)/N_(2)condition or the O_(2)/CO_(2)condition.A further analysis indicated that similar trends of the temperature evolution under different atmospheres were caused by the fact that the strong heat transfer under the fluidized bed condition overwhelmingly dominated the temperature evolution rather than the heat release of the chemical reaction. | Xiehe YANG Yang ZHANG Daoyin LIU Jiansheng ZHANG Hai ZHANG Junfu LYU Guangxi YUE | 2021 | Frontiers in Energy2021，15，1： | 0 |
| 11 | Experimental and Modelling Study on Emission of Volatile Nitrogen Derived NO during Pressured Oxy-fuel Combustion under Wet Flue Gas Environment显示文摘Pressurised oxy-fuel combustion(POFC)is a clean and efficient combustion technology with great potential.Due to the recycling of flue gas,the concentration of steam in the flue gas is higher than that of conventional combustion,which enriches the free radical pool in the flue gas and thus affects the emission of gaseous pollutants.Therefore,further research into the effect of high steam concentrations on NO_(x)emission mechanisms in POFC is necessary.In this work,a fixed-bed reactor was used to conduct combustion experiments of volatiles and combined with chemical kinetic models to study the NO release characteristics for different pressures and steam concentrations in an O_(2)/CO_(2)atmosphere at 800℃/900℃temperature.The results of the study indicated that the volatile nitrogen comes from the pyrolysis of part of pyrrole,pyridine,and all quaternary nitrogen in coal.The increase in temperature promoted the formation of NO during combustion.Higher pressure affects the main reaction pathway for NO formation,promoting NO consumption by HCCO and C_(2)O groups while enhancing the overall NO reduction.Steam promoted NO consumption by NCO.In addition,steam increased the amount of H/OH groups during the reaction,which affected both NO formation and consumption.However,from the overall effect,the steam still inhibits the emission of NO. | ZAN Haifeng CHEN Xiaoping PAN Suyang GENG Pengfei LIU Daoyin MA Jiliang LIANG Cai | 2023 | Journal of Thermal Science2023，32，5： | 0 |
| 12 | Experimental study of the solid circulation rate in a pressurized circulating fluidized bed显示文摘The solid circulation rate is essential for design of pressurized circulating fluidized beds(PCFBs).With increasing pressure from atmospheric pressure to a few bars,the gas density linearly increases with the pressure,which affects the gas-solid flow characteristics.In this work,experiments were performed at room temperature in a cold PCFB apparatus with a riser of 3.3 m in height and 0.05 m in diameter.The solid circulation rate was studied from 20 to 80 kg/(m^(2)·s)under various conditions with increasing pressure from 0.1 to 0.6 MPa and fluidizing gas velocity from around 1.5 to 8.0 m/s for different Geldart B group particles.Most of the conditions were in the flow regimes of core-annulus flow(CAF)only and CAF with a turbulent fluidized bed at the bottom.The trend of the apparent slip factor with the dimensionless slip velocity was similar at different pressures and for different average particle sizes,and it converged to an exponential function.An empirical equation was obtained by fitting the solid circulation rate with the operating parameters(particle transport velocity,particle volume fraction,Archimedes number,and Froude number),which is helpful for design and operation of PCFBs. | Jinding Hu Daoyin Liu Heng Li Cai Liang Xiaoping Chen | 2021 | Particuology2021，19，3： | 0 |
| 13 | Solids flow characteristics and circulation rate in an internally circulating fluidized bed显示文摘Internally circulating fluidized beds(ICFBs)enable effective control of the reactions and heat distribution in reactors.The ICFB contains two or more connected fluidized regions with different gas velocities to promote controlled solid circulation.The control of solid circulation rate(G_(0))is a critical factor.We recorded single particle trajectories by tracing a fluorescent particle,based on which particle flow behaviors were analyzed in different regions.G_(0)was obtained for a wide range of operating parameters.An increase in gas velocity in the down-and upflow beds shortened the particle circulation time in both beds and G_(0)increased significantly.As the static bed height increased,the differential pressure on both sides of the circulation port increased,which resulted in an increase in the solid circulation rate.As the orifice area increased,the flow resistance through the orifice decreased and thus the solid circulation rate increased.G_(0)increased with the decrease in particle size.The gas velocity in the upflowing bed and orifice area was the most important parameter to control the solid circulation rate.G_(0)was compared with the experimental measurements in literature and predictions using the correlation based on Bernoulli’s equation,and they agreed well. | Jinding Hu Daoyin Liu Cai Liang Jiliang Ma Xiaoping Chen Tao Zhang | 2021 | Particuology2021，19，1： | 0 |
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