Experimental Study of Blast Furnace Hearth Drainage Based on Image Analysis

Abstract

A smooth hearth drainage is one of the key requirements for maintaining an efficient blast furnace operation. For achieving this, it is necessary to understand the hearth drainage behavior and the effect of related process parameters. To investigate the drainage, a set of experiments is conducted in a 2D HeleÀShaw model, where the influence of the initial accumulated amount of molten liquids (iron and slag), blast pressure, and slag viscosity on the drainage behavior is studied using water and oil as liquids. To quantify the findings, an image analysisbased algorithm is applied to extract drainage information that is used to analyze the effect of the mentioned process factors on the evolution of the liquid levels and volumes, flow rates, share oil in the outflow, and angle of the interfaces at the outlet. Herein, the implications of the results for the operation of the blast furnace hearth are discussed.

Numerical Analysis of Blast Furnace Hearth Drainage Based on a Simulated Hele–Shaw Model

“…present article, and the experimental results (right) from the Hele-Shaw model. [26] It should be noted that the experimental conditions differed slightly from the simulated ones with respect to initial oil-level thickness (120 mm in the present study, 100 mm in the experiments) and initial liquid-liquid interface level (0 mm in the present study, 10 mm in the experiments). Despite some nonlinearity in the experimental results, the findings are seen to agree quite well.…”

“…Finally, it may be instructive to compare some of the results of the CFD model with the findings of its experimental counterpart and with measurements from an industrial BF. Results from the experimental Hele-Shaw rig have been presented earlier by Liu et al [12,25,26] The upper panels of Figure 17 show a comparison between the simulated liquid levels (left), reproduced from Figure 6 of the 5 (cf. ref.…”

“…Furthermore, it is not easy to examine the effect of certain factors, like coke-free zone and permeability of the packed bed. Considering these challenges and the advantages, including low labor cost, ease to change the geometry and conditions, a VOF-based CFD model was established to simulate the tapping of a Hele-Shaw model that was used in the earlier work by the authors [12,25,26] to theoretically verify the experimental findings and to complement them. For the VOF method, appropriate computational grid size and arrangement are essential to describe the interface shape accurately.…”

“…A common problem of experimental and numerical studies of BF hearth drainage in the literature is that they report results under strongly limited conditions and usually only for a few runs. By contrast to 3D models, a 2D Hele–Shaw model combined with a method for automatic image processing [ 12,25,26 ] is an ingenious experimental device by which hearth drainage can be quantified and visualized, but it is still quite toilsome to undertake the experiments because the slot model has to be carefully cleaned between the experiments (to remove oil that sticks to the glasses). Furthermore, it is not easy to examine the effect of certain factors, like coke‐free zone and permeability of the packed bed.…”

“…a) CFD results reproduced from Figure 6. b) Experimental results reproduced from Figure5(cf. ref [26]. ).…”