Numerical Investigation of Coke Collapse and Size Segregation in the Bell-less Top Blast Furnace

Abstract

The coke collapse phenomenon significantly affects the burden and gas distributions, and further gas utilization and CO 2 emission. Therefore, it is necessary to investigate the coke collapse in blast furnace. A three dimensional model of bell-less top blast furnace is established based on discrete element method (DEM). The effects of chute angle, rotating speed and sinter amount on the coke collapse charateristics are then investigated based on this model. The results show that coke profile changes a lot after its collapse and the collapse region is more than 40% of the furnace radius. Sinter amount affects the coke collapse amount much, followed by chute angle and chute rotating speed. The coke collapse region is affected most by sinter amount, followed by chute rotating speed and chute angle. Large chute angle, higher rotating speed and small sinter amount are recommended for practical operation since they help to obtain a lighter coke size segregation along radius.

Effects of Operational Parameters on Particle Movement and Distribution at the Top of a Bell‐Less Blast Furnace Based on Discrete Element Method

“…To evaluate the radial burden size segregation in the throat of a blast furnace, segregation index (SI) was introduced, which is defined in previous work. [ 20,45,46 ] It can be expressed as follows.where IMR represents the initial mass ratio of each burden in the hopper, and FMR represents the final mass ratio of each burden in the blast furnace throat. Subscript k represents the burden type, where S, P, and O represent sinters, pellets, and lump ores, respectively.…”

“…To evaluate the radial burden size segregation in the throat of a blast furnace, segregation index (SI) was introduced, which is defined in previous work. [20,45,46] It can be expressed as follows.…”

Modelling of phenomena affecting blast furnace burden permeability using the Discrete Element Method (DEM) – A review

“…The interplay of these forces determines the bulk behavior of the flow in the chute, specifically how compact/dilute the flow is at the chute outlet. When it comes to point (2), researchers have researchers have studied the effect of chute design [45] and operation [46,47] on the stream width and thickness, and how these factors affect segregation during layer build-up. These aspects are discussed later, in Section 2.3.…”

“…Mio et al [42] simulated sinter charging onto a coke layer using a full-scale model, showing that the coke layer thickness changes significantly in radial direction after coke collapse. Kou et al [46] also used a full-scale model to investigate coke collapse after sinter charging. They found that the severity of coke collapse depends on the chute angle, rotational speed and the amount of sinter being charged.…”

“…5. Radial burden profiles before (top) and after (bottom) collapse, where yellow, black and green particles represent sinter base, coke and charged sinter, respectively; image adopted from [46]. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)…”