Life Extension of BOF Lower Hood at U. S. Steel Canada's Lake Erie Works Via Engineering and Design Changes

摘要

A basic oxygen furnace (BOF) hood system removes gaseous effluents and prevents their emission into the steel shop or the atmosphere. A BOF hood is essentially a large heat exchanger, with the heat from the gas stream being transferred through the plates/cooling water tubes to the cooling water. Depending upon the design, the transferred heat is either utilized (as hot water or steam) or dissipated at the cooling tower and the water recycled. The water quality plays a major role in establishing the onset and progress of deterioration of the inside surfaces of the plates/tubes and controlling the heat transfer. Conversely, the steel making effluents are largely responsible for the deterioration of the outer surfaces of lates/tubes. Variables in the steel making process control the composition, volume and heat content of the BOF effluent gases and particulates. The design of the hood system and the actual layout of the hood in the shop in combination with the operational variables play important roles with the generation of the gaseous environment at the BOF vessel mouth. The particulates, moving at high velocities, impinge upon components of the hood causing erosive wear on the hot side. An efficient BOF hood system is designed to capture the furnace gases, to provide a combustion chamber for generating heat from the off-gas, to process the heat for energy recovery, and to clean properly and cool the gases before their discharge. A cost effective hood is expected to fulfill the above functions with the lowest possible initial and maintenance costs, while providing the longest possible service life.