Experiments on simultaneous absorption of SO_2 and NO_X from sintering flue gas via a composite absorbent NaClO_2/NaClO were carried out. The effects of various operating parameters such as NaClO_2 concentration(ms), ...Experiments on simultaneous absorption of SO_2 and NO_X from sintering flue gas via a composite absorbent NaClO_2/NaClO were carried out. The effects of various operating parameters such as NaClO_2 concentration(ms), NaClO concentration(mp), molar ratio of NaClO_2/NaClO(M), solution temperature(TR), initial solution pH, gas flow(Vg) and inlet concentration of SO_2(CS) and NO(CN) on the removal efficiencies of SO_2 and NO were discussed. The optimal experimental conditions were determined to be initial solution pH = 6, TR=55 °C and M = 1.3 under which the average efficiencies of desulfurization and denitrification could reach99.7% and 90.8%, respectively. Moreover, according to the analysis of reaction products, it was found that adding NaClO to NaClO_2 aqueous solution is favorable for the generation of ClO_2 and Cl_2 which have significant effect on desulfurization and denitrification. Finally, engineering experiments were performed and obtained good results demonstrating that this method is practicable and promising.展开更多
This paper analyses three popular methods simulating granular flow at different time and length scales:discrete element method (DEM), averaging method and viscous, elastic-plastic continuum model. The theoretical mode...This paper analyses three popular methods simulating granular flow at different time and length scales:discrete element method (DEM), averaging method and viscous, elastic-plastic continuum model. The theoretical models of these methods and their applications to hopper flows are discussed. It is shown that DEM is an effective method to study the fundamentals of granular flow at a particle or microscopic scale. By use of the continuum approach, granular flow can also be described at a continuum or macroscopic scale. Macroscopic quantities such as velocity and stress can be obtained by use of such computational method as FEM. However, this approach depends on the constitutive relationship of materials and ignores the effect of microscopic structure of granular flow. The combined approach of DEM and averaging method can overcome this problem. The approach takes into account the discrete nature of granular materials and does not require any global assumption and thus allows a better understanding of the fundamental mechanisms of granular flow. However, it is difficult to adapt this approach to process modelling because of the limited number of particles which can be handled with the present computational capacity, and the difficulty in handling non-spherical particles.Further work is needed to develop an appropriate approach to overcome these problems.展开更多
The packing of cohesive particles is of paramount importance in many industries because the packing structure is closely related to process performance.A general relation between packing density and interparticle forc...The packing of cohesive particles is of paramount importance in many industries because the packing structure is closely related to process performance.A general relation between packing density and interparticle force was previously proposed based on packing structures formed without dynamic fluid flows.Its universality is examined here in two different packings,formed in settling and defluidization of static and dynamic fluids,respectively.First,it is shown that the packings of the same particles formed by two different methods have different structures because of different impact-induced pressures.Nevertheless,a one-to-one relationship between packing density and structural properties still holds regardless of the different packing methods,and the force distribution in those packings obeys similar rules.Finally,the packing densities obtained by the different methods are demonstrated to be universally correlated with the ratio of the interparticle force to the effective gravity.These findings indicate that different phenomena of particulate systems at a macro-or meso-scale may share similar microscopic origins,with the interparticle force playing a crucial role.展开更多
基金Supported by the National Science Foundation of China for Distinguished Young Scholars(No.51325601)Major Program of National Science Foundation of China(No.51390492)Joint Funds of National Science Foundation of China(No.U1560205)
文摘Experiments on simultaneous absorption of SO_2 and NO_X from sintering flue gas via a composite absorbent NaClO_2/NaClO were carried out. The effects of various operating parameters such as NaClO_2 concentration(ms), NaClO concentration(mp), molar ratio of NaClO_2/NaClO(M), solution temperature(TR), initial solution pH, gas flow(Vg) and inlet concentration of SO_2(CS) and NO(CN) on the removal efficiencies of SO_2 and NO were discussed. The optimal experimental conditions were determined to be initial solution pH = 6, TR=55 °C and M = 1.3 under which the average efficiencies of desulfurization and denitrification could reach99.7% and 90.8%, respectively. Moreover, according to the analysis of reaction products, it was found that adding NaClO to NaClO_2 aqueous solution is favorable for the generation of ClO_2 and Cl_2 which have significant effect on desulfurization and denitrification. Finally, engineering experiments were performed and obtained good results demonstrating that this method is practicable and promising.
文摘This paper analyses three popular methods simulating granular flow at different time and length scales:discrete element method (DEM), averaging method and viscous, elastic-plastic continuum model. The theoretical models of these methods and their applications to hopper flows are discussed. It is shown that DEM is an effective method to study the fundamentals of granular flow at a particle or microscopic scale. By use of the continuum approach, granular flow can also be described at a continuum or macroscopic scale. Macroscopic quantities such as velocity and stress can be obtained by use of such computational method as FEM. However, this approach depends on the constitutive relationship of materials and ignores the effect of microscopic structure of granular flow. The combined approach of DEM and averaging method can overcome this problem. The approach takes into account the discrete nature of granular materials and does not require any global assumption and thus allows a better understanding of the fundamental mechanisms of granular flow. However, it is difficult to adapt this approach to process modelling because of the limited number of particles which can be handled with the present computational capacity, and the difficulty in handling non-spherical particles.Further work is needed to develop an appropriate approach to overcome these problems.
基金The authors are grateful to the Australian Research Council(IH140100035,DE180100266)the Natural Science Foundation of China(91534206)for financial support+1 种基金YLW is also grateful to China Scholarship Council(CSC)the Faculty of Engineering at Monash University for a scholarship.
文摘The packing of cohesive particles is of paramount importance in many industries because the packing structure is closely related to process performance.A general relation between packing density and interparticle force was previously proposed based on packing structures formed without dynamic fluid flows.Its universality is examined here in two different packings,formed in settling and defluidization of static and dynamic fluids,respectively.First,it is shown that the packings of the same particles formed by two different methods have different structures because of different impact-induced pressures.Nevertheless,a one-to-one relationship between packing density and structural properties still holds regardless of the different packing methods,and the force distribution in those packings obeys similar rules.Finally,the packing densities obtained by the different methods are demonstrated to be universally correlated with the ratio of the interparticle force to the effective gravity.These findings indicate that different phenomena of particulate systems at a macro-or meso-scale may share similar microscopic origins,with the interparticle force playing a crucial role.
