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Experimental and numerical study of the flow field and temperature field for a large - scale radiant syngas cooler / Jianjun Ni in Industrial & engineering chemistry research, Vol. 51 N° 51 (Décembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp.4452–4461 Titre : Experimental and numerical study of the flow field and temperature field for a large - scale radiant syngas cooler Type de document : texte imprimé Auteurs : Jianjun Ni, Auteur ; Guangsuo Yu, Auteur ; Qinghua Guo, Auteur Année de publication : 2012 Article en page(s) : pp.4452–4461 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Gas  Temperature Résumé : Experimental and numerical studies on the gas-particle flow field and temperature field in the industrial-scale radiant syngas cooler (RSC) have been carried out. The bench-scale cold model experiment was presented for measuring the gas flow field in the RSC. The accuracy and performance of four turbulent flow models were evaluated according to the comparison of predicted results with experimental results. The ash particle trajectories were predicted by the stochastic Lagrangian model and the interaction between the gas and particle phase was also considered by two-way coupling method. A discrete ordinate model (DOM) was used for solving the radiative heat transfer equation when the radiative properties were calculated by weighted-sum-of-gray-gases model (WSGGM). The Ranz−Marshall correlation for the Nusselt number was used to account for convection heat-transfer between the gas phase and the particle phase. The ash particle radiative heat transfer was also considered. The physical properties of gas mixtures were calculated by the mass-weighted-mixing law. The results indicate that the inlet jet flow intensity is dependent on the inlet diameter, but the length of the jet is independent of the inlet diameter. The thickness of the deposition on the membrane wall has great influence on the heat-transfer. The average temperature profiles of particle are higher than gas in the inner cylinder, and it is inversed in the annular. Furthermore, the results show that particles sizes smaller than 580 μm will be entrained into the annular, but the particle size between 400 and 580 μm cannot be entrained out. And the escaping particle’s temperature is lower than the critical temperature when the deposition thickness is 0.2 mm. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100014r [article] Experimental and numerical study of the flow field and temperature field for a large - scale radiant syngas cooler [texte imprimé] / Jianjun Ni, Auteur ; Guangsuo Yu, Auteur ; Qinghua Guo, Auteur . - 2012 . - pp.4452–4461. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp.4452–4461 Mots-clés : Gas  Temperature Résumé : Experimental and numerical studies on the gas-particle flow field and temperature field in the industrial-scale radiant syngas cooler (RSC) have been carried out. The bench-scale cold model experiment was presented for measuring the gas flow field in the RSC. The accuracy and performance of four turbulent flow models were evaluated according to the comparison of predicted results with experimental results. The ash particle trajectories were predicted by the stochastic Lagrangian model and the interaction between the gas and particle phase was also considered by two-way coupling method. A discrete ordinate model (DOM) was used for solving the radiative heat transfer equation when the radiative properties were calculated by weighted-sum-of-gray-gases model (WSGGM). The Ranz−Marshall correlation for the Nusselt number was used to account for convection heat-transfer between the gas phase and the particle phase. The ash particle radiative heat transfer was also considered. The physical properties of gas mixtures were calculated by the mass-weighted-mixing law. The results indicate that the inlet jet flow intensity is dependent on the inlet diameter, but the length of the jet is independent of the inlet diameter. The thickness of the deposition on the membrane wall has great influence on the heat-transfer. The average temperature profiles of particle are higher than gas in the inner cylinder, and it is inversed in the annular. Furthermore, the results show that particles sizes smaller than 580 μm will be entrained into the annular, but the particle size between 400 and 580 μm cannot be entrained out. And the escaping particle’s temperature is lower than the critical temperature when the deposition thickness is 0.2 mm. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100014r

Modeling of multiphase flow and heat transfer in radiant syngas cooler of an entrained-flow coal gasification / Guangsuo Yu in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10094–10103 Titre : Modeling of multiphase flow and heat transfer in radiant syngas cooler of an entrained-flow coal gasification Type de document : texte imprimé Auteurs : Guangsuo Yu, Auteur ; Jianjun Ni, Auteur ; Qinfeng Liang, Auteur Année de publication : 2010 Article en page(s) : pp. 10094–10103 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : A comprehensive model has been developed to analyze the multiphase flow and heat transfer in the radiant syngas cooler (RSC) of an industrial-scale entrained-flow coal gasification. The three-dimensional multiphase flow field and temperature field were reconstructed. The realizable k−ϵ turbulence model is applied to calculate the gas flow field, while the discrete random walk model is applied to trace the particles, and the interaction between the gas and the particle is considered using a two-way coupling model. The radiative properties of syngas mixture are calculated by weighted-sum-of-gray-gases model (WSGGM). The Ranz−Marshall correlation for the Nusselt number is used to account for convection heat transfer between the gas phase and the particles. The discrete ordinate model is applied to model the radiative heat transfer, and the effect of ash/slag particles on radiative heat transfer is considered. The model was successfully validated by comparison with the industrial plant measurement data, which demonstrated the ability of the model to optimize the design. The results show that a torch shape inlet jet was formed in the RSC, and its length increased with the diameter of the central channel. The recirculation zones appeared around the inlet jet, top, and bottom of the RSC. The overall temperature decreased with the heat-transfer surface area of the fins. The concentration distribution, velocity distribution, residence time distribution, and temperature distribution of particles with different diameters have been discussed. Finally, the slag/ash particles size distribution and temperature profile at the bottom of the RSC have been presented. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901203d [article] Modeling of multiphase flow and heat transfer in radiant syngas cooler of an entrained-flow coal gasification [texte imprimé] / Guangsuo Yu, Auteur ; Jianjun Ni, Auteur ; Qinfeng Liang, Auteur . - 2010 . - pp. 10094–10103. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10094–10103 Résumé : A comprehensive model has been developed to analyze the multiphase flow and heat transfer in the radiant syngas cooler (RSC) of an industrial-scale entrained-flow coal gasification. The three-dimensional multiphase flow field and temperature field were reconstructed. The realizable k−ϵ turbulence model is applied to calculate the gas flow field, while the discrete random walk model is applied to trace the particles, and the interaction between the gas and the particle is considered using a two-way coupling model. The radiative properties of syngas mixture are calculated by weighted-sum-of-gray-gases model (WSGGM). The Ranz−Marshall correlation for the Nusselt number is used to account for convection heat transfer between the gas phase and the particles. The discrete ordinate model is applied to model the radiative heat transfer, and the effect of ash/slag particles on radiative heat transfer is considered. The model was successfully validated by comparison with the industrial plant measurement data, which demonstrated the ability of the model to optimize the design. The results show that a torch shape inlet jet was formed in the RSC, and its length increased with the diameter of the central channel. The recirculation zones appeared around the inlet jet, top, and bottom of the RSC. The overall temperature decreased with the heat-transfer surface area of the fins. The concentration distribution, velocity distribution, residence time distribution, and temperature distribution of particles with different diameters have been discussed. Finally, the slag/ash particles size distribution and temperature profile at the bottom of the RSC have been presented. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901203d

Molten slag flow and phase transformation behaviors in a slagging entrained - flow coal gasifier / Jianjun Ni in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12302–12310 Titre : Molten slag flow and phase transformation behaviors in a slagging entrained - flow coal gasifier Type de document : texte imprimé Auteurs : Jianjun Ni, Auteur ; Zhijie Zhou, Auteur ; Guangsuo Yu, Auteur Année de publication : 2011 Article en page(s) : pp. 12302–12310 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Coal  Phase  transformation  Slag Résumé : A slag flow submodel has been developed to simulate the slag flow and phase transformation behaviors in coal gasifiers. The volume of the fluid (VOF) model is used to capture the free surface of the slag flow, and the continuum surface force (CSF) model is employed to calculate the surface tension between the gas phase and the liquid slag phase. The slag is treated as a Newtonian fluid when the slag temperature is above the critical viscosity temperature (Tcv), and plastic fluid is treated when the slag temperature is between the flow temperature (Tf) and the Tcv. The ash particle deposition, viscosity−temperature dependence, and different thermal conductivity for different slag phase are all included in the present simulation. For membrane wall coal gasification, the liquid slag and solid slag layer increases along the flow and total slag thickness increases as the operating temperature decreases. The velocity profiles and viscosity profiles at different operating temperatures are performed. The liquid slag flow will produce fluctuations when the slag temperature decreases to the lowest at the bottom of the gasifier. In addition, the temperature difference (To − Tf) between 150 and 200 °C is suitable for a membrane wall coal entrained-flow gasifier. For refractory wall coal gasification, the thicker refractory bricks can effectively prevent the heat lost from the gasifier wall, so the slag flow is steady when the operating temperature is higher than the critical operating temperature. An expression of solid slag layer formation criterion has been deduced from heat-transfer balance. The critical operating temperature of the different slag mass flow rate is studied by heat-transfer balance. In addition, the solid slag layer will rapidly increase as the operating temperature decreases to critical operating temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463395 [article] Molten slag flow and phase transformation behaviors in a slagging entrained - flow coal gasifier [texte imprimé] / Jianjun Ni, Auteur ; Zhijie Zhou, Auteur ; Guangsuo Yu, Auteur . - 2011 . - pp. 12302–12310. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12302–12310 Mots-clés : Coal  Phase  transformation  Slag Résumé : A slag flow submodel has been developed to simulate the slag flow and phase transformation behaviors in coal gasifiers. The volume of the fluid (VOF) model is used to capture the free surface of the slag flow, and the continuum surface force (CSF) model is employed to calculate the surface tension between the gas phase and the liquid slag phase. The slag is treated as a Newtonian fluid when the slag temperature is above the critical viscosity temperature (Tcv), and plastic fluid is treated when the slag temperature is between the flow temperature (Tf) and the Tcv. The ash particle deposition, viscosity−temperature dependence, and different thermal conductivity for different slag phase are all included in the present simulation. For membrane wall coal gasification, the liquid slag and solid slag layer increases along the flow and total slag thickness increases as the operating temperature decreases. The velocity profiles and viscosity profiles at different operating temperatures are performed. The liquid slag flow will produce fluctuations when the slag temperature decreases to the lowest at the bottom of the gasifier. In addition, the temperature difference (To − Tf) between 150 and 200 °C is suitable for a membrane wall coal entrained-flow gasifier. For refractory wall coal gasification, the thicker refractory bricks can effectively prevent the heat lost from the gasifier wall, so the slag flow is steady when the operating temperature is higher than the critical operating temperature. An expression of solid slag layer formation criterion has been deduced from heat-transfer balance. The critical operating temperature of the different slag mass flow rate is studied by heat-transfer balance. In addition, the solid slag layer will rapidly increase as the operating temperature decreases to critical operating temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463395