The experiments on the flash pyrolysis of a lignite were carried out in a fast-entrained bed reactor as a basic study on a so-called ＇ coal topping process＇. The investigation focused on the effects of pyrolysis tem...The experiments on the flash pyrolysis of a lignite were carried out in a fast-entrained bed reactor as a basic study on a so-called ＇ coal topping process＇. The investigation focused on the effects of pyrolysis temperature and coal particle size on the product distribution and composition. The experimental results show that an increase in the pyrolysis temperature results in a higher yield of gaseous products while a larger particle size leads to a decrease of the liquid yield. An optimum temperature for the liquid yield was found to be 650℃. A certain amount of phenol groups was found in the liquid products, which may be used to produce high-valued fine chemicals. The FTIR analyses of the coal and chars show that aliphatic structures in the chars are gradually replaced by aromatic structures with the increasing of pyrolysis temperature and coal particle size. The results of this study provide fundamental data and optimal conditions to maximize light oils yields for the coal topping process.展开更多
The surface tension of molten tin was determined by a set of self-developed digital equipment with sessile drop method at oxygen partial pressure of 1.0×10 -6MPa under different temperatures, and the dependence...The surface tension of molten tin was determined by a set of self-developed digital equipment with sessile drop method at oxygen partial pressure of 1.0×10 -6MPa under different temperatures, and the dependence of surface tension of molten tin on temperature was also discussed. The emphasis was placed on the comparison of surface tension of the same molten tin sample measured by using different equipments with sessile drop method. Results of the comparison indicate that the measurement results with sessile drop method under the approximate experimental conditions are coincident, and the self-developed digital equipment for surface tension measurement has higher stability and accuracy. The relationships of surface tension of molten tin and its temperature coefficient with temperature and oxygen partial pressure were also elucidated from the thermodynamic equilibrium analysis.展开更多
Mixing/Segregation of an iron-and-sand mixture was investigated in a 38 mm diameter moving fluidizedbed with feed into the middle of the bed and exit from both the top and the bottom.The distribution ofvolumetric conc...Mixing/Segregation of an iron-and-sand mixture was investigated in a 38 mm diameter moving fluidizedbed with feed into the middle of the bed and exit from both the top and the bottom.The distribution ofvolumetric concentration of iron beads,measured by means of a specially designed sampler,was used to expressthe degree of segregation of the particle mixture in the bed.The segregation index N,defined as the ratio betweenS and Z.X_v,decreases with increase in superficial gas velocity and solids flow rate,for any given solidsdensity ratio and particle size ratio.When a magnetic field was employed,particle segregation was noted toincrease with magnetic field strength.展开更多
A parallel algorithm suitable for simulating multi-sized particle systems and multi-phase fluid systems is proposed based on macro-scale pseudo-particle modeling(MaPPM).The algorithm employs space-decomposition of the...A parallel algorithm suitable for simulating multi-sized particle systems and multi-phase fluid systems is proposed based on macro-scale pseudo-particle modeling(MaPPM).The algorithm employs space-decomposition of the computational load among the processing ele-ments(PEs)and multi-level cell-subdivision technique for particle indexing.In this algorithm,a 2D gas-solid system is simulated with the temporal variations of drags on solids,inter-phase slip velocities and solids concentration elaborately monitored.Analysis of the results shows that the algorithm is of good parallel efficiency and scalability,demonstrating the unique advantage of MaPPM in simulating complex flows.展开更多
Mesoporous silica was prepared using tetrathoxysilane （TEOS）, cetadecyltrimethylammonium bromide （CTAB）, aqueous ammonia, acetone and water as silica source, template agent, precipitator and solvent respectively. ...Mesoporous silica was prepared using tetrathoxysilane （TEOS）, cetadecyltrimethylammonium bromide （CTAB）, aqueous ammonia, acetone and water as silica source, template agent, precipitator and solvent respectively. Stearic acid and polyvinylpyrrolidone （PVP） were employed as additional templates to tailor the pore size in the resultant porous silica. BET, SAXRD and SEM analyses were used to characterize the surface area, pore size, pore structure, pore regularity and morphology of the sample. BET measurement results showed that PVP could increase the surface area but diminish the pore size while stearic acid could decrease the surface area but enlarge the pore size. SAXRD analysis indicated that more additional template introduction gave rise to less order-structured products. All these various results could be attributed to the differently modified CTAB micelles involving stearic acid and PVP addition.展开更多
文摘The experiments on the flash pyrolysis of a lignite were carried out in a fast-entrained bed reactor as a basic study on a so-called ＇ coal topping process＇. The investigation focused on the effects of pyrolysis temperature and coal particle size on the product distribution and composition. The experimental results show that an increase in the pyrolysis temperature results in a higher yield of gaseous products while a larger particle size leads to a decrease of the liquid yield. An optimum temperature for the liquid yield was found to be 650℃. A certain amount of phenol groups was found in the liquid products, which may be used to produce high-valued fine chemicals. The FTIR analyses of the coal and chars show that aliphatic structures in the chars are gradually replaced by aromatic structures with the increasing of pyrolysis temperature and coal particle size. The results of this study provide fundamental data and optimal conditions to maximize light oils yields for the coal topping process.
文摘The surface tension of molten tin was determined by a set of self-developed digital equipment with sessile drop method at oxygen partial pressure of 1.0×10 -6MPa under different temperatures, and the dependence of surface tension of molten tin on temperature was also discussed. The emphasis was placed on the comparison of surface tension of the same molten tin sample measured by using different equipments with sessile drop method. Results of the comparison indicate that the measurement results with sessile drop method under the approximate experimental conditions are coincident, and the self-developed digital equipment for surface tension measurement has higher stability and accuracy. The relationships of surface tension of molten tin and its temperature coefficient with temperature and oxygen partial pressure were also elucidated from the thermodynamic equilibrium analysis.
文摘Mixing/Segregation of an iron-and-sand mixture was investigated in a 38 mm diameter moving fluidizedbed with feed into the middle of the bed and exit from both the top and the bottom.The distribution ofvolumetric concentration of iron beads,measured by means of a specially designed sampler,was used to expressthe degree of segregation of the particle mixture in the bed.The segregation index N,defined as the ratio betweenS and Z.X_v,decreases with increase in superficial gas velocity and solids flow rate,for any given solidsdensity ratio and particle size ratio.When a magnetic field was employed,particle segregation was noted toincrease with magnetic field strength.
基金This work was supported by the National Key Program for Developing Basic Sciences(Grant No.G1999032801)the National Natural Science Foundation of China(Grant Nos.20336040and 20221603)the Chinese Academy of Sciences(Grant No.INF105-SCE-2-07).
文摘A parallel algorithm suitable for simulating multi-sized particle systems and multi-phase fluid systems is proposed based on macro-scale pseudo-particle modeling(MaPPM).The algorithm employs space-decomposition of the computational load among the processing ele-ments(PEs)and multi-level cell-subdivision technique for particle indexing.In this algorithm,a 2D gas-solid system is simulated with the temporal variations of drags on solids,inter-phase slip velocities and solids concentration elaborately monitored.Analysis of the results shows that the algorithm is of good parallel efficiency and scalability,demonstrating the unique advantage of MaPPM in simulating complex flows.
基金supported by the National Natural Science Foundation of China(No.20221603)the Chinese Academy of Sciences.
文摘Mesoporous silica was prepared using tetrathoxysilane （TEOS）, cetadecyltrimethylammonium bromide （CTAB）, aqueous ammonia, acetone and water as silica source, template agent, precipitator and solvent respectively. Stearic acid and polyvinylpyrrolidone （PVP） were employed as additional templates to tailor the pore size in the resultant porous silica. BET, SAXRD and SEM analyses were used to characterize the surface area, pore size, pore structure, pore regularity and morphology of the sample. BET measurement results showed that PVP could increase the surface area but diminish the pore size while stearic acid could decrease the surface area but enlarge the pore size. SAXRD analysis indicated that more additional template introduction gave rise to less order-structured products. All these various results could be attributed to the differently modified CTAB micelles involving stearic acid and PVP addition.
