Simulation Study on the Interaction between Chemically Reacting Double Coal Char Particles

Abstract

Due to the complex atmosphere of the entrained flow gasifier, it is difficult to obtain reactivity properties of coal char particles under high-temperature conditions by experiment. The computational fluid dynamics simulation method is a key way to simulate the reactivity of coal char particles. In this article, the gasification characteristics of double coal char particles under H 2 O/ O 2 /CO 2 atmosphere are studied. The results show that the particle distance (L) has an influence on the reaction with particles. With the gradual increase of L, the temperature first rises and then falls among the double particles due to the migration of the reaction area, and the characteristics of double coal char particles gradually approach that of single coal char particles. The particle size also has an influence on the gasification characteristics of coal char particles. As the particle size varies from 0.1 to 1 mm, the reaction area of particles becomes smaller at high temperature and finally attaches to the surface of the particles. The reaction rate and carbon consumption rate increase with increasing particle size. As the size of double particles is changed, the reaction rate trend of double coal char particles at the same particle distance is basically the same, but the change degree of reaction rate is different. With the increase of the distance between coal char particles, the change of the carbon consumption rate is larger for the small particle size.

Nanoscopic Imaging of Self-Propelled Ultrasmall Catalytic Nanomotors

“…This quenched disorder could serve to induce a continuous time random walk (CTRW) behavior that underlies the fractional temporal power law decay of K(t) on intermediate time scales and hence subdiffusive MSD−Δt behaviors. 45 For the propelled NPs in NaBH 4 , an additional propulsive force is added, leading to superdiffusive motion observed at short time scales (generally <2 s based on experimental observation shown in Figure 5c,d). Such a superdiffusive regime cannot be observed in passive NPs in NaCl, differentiating the two systems with and without driving force.…”