Portable Acoustic Instrumentation for blast Furnace Wall Diagnostics

摘要

A blast furnace is a tall, vertical shaft furnace lined with refractory brick, which employs carbon, mainly in the form of coke, to chemically reduce and physically convert iron oxides into liquid iron for subsequent refining to steel in other processes. The refractory brickwork which forms the hearth, bosh and in walls of a blast furnace is referred to as the lining. The bricks are required to sustain the high temperature and erosion of iron and slag flow. Hearth refractory wear is the most dominant factor affecting the campaign life of a blast furnace. Wear of carbon refractory occurs primarily because of erosion, mostly resulting from a combination of chemical, hydrodynamic and thermo-mechanical phenomena. An assessment of the refractory thickness changes, and therefore molten metal flow patterns, is essential to reduce the erosion rate. Reliable monitoring of this erosion allows for more accurate computational fluid dynamics modeling, more timely preventative maintenance, and a maximization of the campaign life of these reactors. The extenuation of lifetime of the existing and new blast furnaces strongly depends on the opportunity for direct measurements of the blast furnace wall destruction and damage accumulation. There have been many attempts to evaluate the hearth wear profile, including radioisotopes and a temperature control method using embedded sensors. There were also attempts to develop acoustic methods, such as the pulse-echo technique and acoustic resonance technique. This paper presents a brief review of the linear and nonlinear acoustic methods that can be used for blast furnace wall diagnostics, and reflects the progress in the development of portable acoustic instrumentation using some of these methods.