Title

NUMERICAL SIMULATION ON DYNAMIC AND STATICHOLDUPS OF POWDER INSIDE PRE-REDUCTION SHAFTFURNACE

NUMERICAL SIMULATION ON DYNAMIC AND STATICHOLDUPS OF POWDER INSIDE PRE-REDUCTION SHAFTFURNACE

Authorship

DU., KAI-PING; XU, JIAN; WU, SHENG-LI; GUO, XIN-YING

DU., KAI-PING

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XU, JIAN

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WU, SHENG-LI

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GUO, XIN-YING

I am this author

DOI

10.5151/2594-357X-22110

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Abstract

In some non-blast furnace ironmaking processes, such as COREX smelting reduction process, the reducing gas, introduced into the upper pre-reduction shaft furnace, usually contains a considerable quantity of dust or powder as a result of coal gasification and iron-bearing burden decomposition in melter gasifier, and the powder distribution behaviors make direct and important influences on gas flow as well as burden reduction inside pre-reduction shaft furnace. Based on momentum exchange among gas-solid-powder phases and empirical equations, a two-dimensional mathematical model was established in the present work to simulate both dynamic and static holdups of powder. There were two blockade zones existing in the centre and edge regions near the bottom respectively. The dynamic holdup of powder firstly increased to 3.0e-3 and then decreased to 7.0e-4 as the gas ascended from the inlet to the top. At the bottom of the shaft furnace, the relatively low gas velocity gave rise to dynamic powder accumulation. By contrast, the static holdup of powder generally increased from 2.0e-5 near the edge to as high as 1.8e-4 near the centre at the gas inlet level and the trend was further promoted to 5.0e-3 in the central inactive zone or even to 1.0e-1 at the bottom below the gas inlet. In addition, the influences of the powder density, the feed rate and the man-made deadman shape on powder distribution behaviors inside pre-reduction shaft furnace were also investigated in this work.

In some non-blast furnace ironmaking processes, such as COREX smelting reduction process, the reducing gas, introduced into the upper pre-reduction shaft furnace, usually contains a considerable quantity of dust or powder as a result of coal gasification and iron-bearing burden decomposition in melter gasifier, and the powder distribution behaviors make direct and important influences on gas flow as well as burden reduction inside pre-reduction shaft furnace. Based on momentum exchange among gas-solid-powder phases and empirical equations, a two-dimensional mathematical model was established in the present work to simulate both dynamic and static holdups of powder. There were two blockade zones existing in the centre and edge regions near the bottom respectively. The dynamic holdup of powder firstly increased to 3.0e-3 and then decreased to 7.0e-4 as the gas ascended from the inlet to the top. At the bottom of the shaft furnace, the relatively low gas velocity gave rise to dynamic powder accumulation. By contrast, the static holdup of powder generally increased from 2.0e-5 near the edge to as high as 1.8e-4 near the centre at the gas inlet level and the trend was further promoted to 5.0e-3 in the central inactive zone or even to 1.0e-1 at the bottom below the gas inlet. In addition, the influences of the powder density, the feed rate and the man-made deadman shape on powder distribution behaviors inside pre-reduction shaft furnace were also investigated in this work.

Keywords

Mathematical model; Powder phase; Holdup distribution; Pre-reductionshaft furnace.

Mathematical model; Powder phase; Holdup distribution; Pre-reductionshaft furnace.