Operation practices and Campaign Life of a Blast Furnace May11

Operation practices and Campaign Life of a Blast Furnace...

Operation practices and Campaign Life of a Blast Furnace The cost of rebuilding or relining a blast furnace (BF) is very high. Hence techniques to extend BF campaign lives are important and need to be pursued very actively. Large BFs usually have a slightly higher campaign output per unit volume. This difference is because larger BFs generally are of more modern design and well automated.  Since the viability of an integrated steel plant depends on a continuous supply of hot metal (HM), which in a plant with a small number of large furnaces puts great importance on long campaign life. The techniques for prolongation of BF campaign life (Fig 1) falls under the following three categories. Operational practices – The control of the BF process has a major effect on the campaign life. BF is to be operated not only for meeting the production needs but also to maximize its life. Hence it is necessary to modify operating practices as the campaign progresses and in response to the problem areas for the maximization of campaign life. Remedial actions – Once wear or damage that affects the life of the BF becomes evident, engineering repair techniques are to be used or developed to maximize campaign life. Improved designs – As improved materials and equipment are developed, these are to be incorporated into future rebuilds to extend the life of critical areas of the BF, where it is cost effective to do so.   Fig 1 Techniques for prolongation of blast furnace campaign life Operational practices for improved campaign life are discussed in this article. The operating practices affecting the BF campaign life are described below. Productivity The productivity of a BF is normally expressed in tons (t) of HM per unit BF volume (cum) per...

Blast Furnace Tap Hole Mass...

Blast Furnace Tap Hole Mass Blast furnace tap hole mass is a prepared ready to use refractory product, made of a bond of aggregates, additives, and plasticizers. It is used to close the tap hole of a blast furnace after tapping so that no material can leak out, and to keep it plugged until the tap hole is opened for next tapping. It is applied to ensure periodical and stable tapping from the blast furnace and also to protect the inner surface of tap hole bricks. Its functions are (i) to enable smooth operation of the tap hole, (ii) to maintain constant tap hole length,  (iii) to control the liquid flow out of the blast furnace, and (iv) to ensure separation of hot metal and slag. Blast furnace tap hole mass is normally developed and designed to suit the operating parameters of the blast furnace and to maintain stable tapping time and tap hole depth even under severe operational conditions with high productivity coefficients (ton/cu m/day) or high hot metal temperatures. Requirements of blast furnace tap hole mass Typical requirements from the blast furnace tap hole mass include the following. It should be soft and plastic (workable) enough to inject when pushed by mud gun, but ‘hard’ enough to effectively displace tapping liquid and to deliver a substantial quantity of tap hole mass only to plug to the required depth in the tapping channel. It should be curing to the required strength (often described as sinterability) and without shrinkage to ensure a tight seal within the tap hole (not prematurely in the mud gun), in the required mud gun dwell time and plug to next tap time. It should effect safe tap hole closure (i.e., without subsequently self opening) and without tap hole and...