Numerical Modeling of Iron Flow and Bottom Erosion in the Blast FurnaceHearthduringthe Tapping Process

摘要

The campaign life of a blast furnace (BF) is determined by its lowest part,i.e.the hearth,which suffers from severe erosion.It is impossible to directly monitor the state of the hearth,and the furnace has to be stopped if the hearth is severely worn.Timely prediction of the hearth erosion is therefore prerequisite for a stable BF operation where proper measures are taken to protect the hearth lining.Even if the bottom is believed to be a vulnerable part of the hearth,the erosion of it has not received much attention.A comprehensive computational fluid dynamic (CFD) model is developed to extend the relevant knowledge on fluid flow and refractory erosion,especially at the hearth bottom.For the CFD model,the time-dependent dead man state is computed by a BF drainage model,which is based on first principles and is capable to reproduce the overall behavior of the tap cycles.Simulations with the CFD model are applied to illustrate how the main factors in the hearth,such as the flow pattern and bottom erosion ratio,evolve during the iron-only flow period of a typical tapping process.It is demonstrated that the dead man plays an important role for the flow behavior and erosion conditions in the BF hearth.