Kinetics parameters of iron oxide reduction by hydrogen were evaluated by the isothermal method in a differential micro-packed bed. Influence of external diffusion, internal diffusion and heat transfer on the intrinsic reaction rate was investigated and the conditions free of internal and external diffusion resistance have been determined. In the experiments, in order to correctly evaluate the intrinsic kinetics parameters for reducing Fe203 to Fe3O4, the reaction temperatures were set between 440 ℃ and 490 ℃. However, in order to distinguish the reduction of Fe304 to FeO from that of FeO to Fe, the reaction temperature in the experiment was set to be greater than 570 ℃. Intrinsic kinetics of iron oxide reduction by hydrogen was established and the newly established kinetic models were validated by the experimental data.
Carbon nanotubes(CNTs) are nanomaterials that have attracted great research interest because of their unique properties and promising applications.The controllable synthesis of CNTs is a precondition for their broad application.In this review,we consider nanoscale process engineering and assess recent progress in the mass production of ultra-long,inexpensive CNTs with good alignment as well as tunability in wall number and diameter for fundamental and engineering science applications across multiple scales.Cutting-edge nanoscale process engineering research in the areas of physics,chemistry,materials,engineering,ecology,and social science will allow us to obtain high added value and multi-functional advanced CNTs.The synthesis of CNTs with controllable chirality,good-alignment,and predetermined sizes and lengths still presents great challenges.Through multidisciplinary scientific research,advanced CNT-based materials will promote the development of a sustainable society.
