Blast Furnace and its Design Dec03

Blast Furnace and its Design...

Blast Furnace and its Design The design of a blast furnace (BF) plays a fundamental role in its reliable operation, metallurgical performance, sustained high productivity and long campaign life. The design of a modern BF is generally based on the concept of a free standing unit with a surrounding building structure, providing access to the furnace and support for the BF gas system. BF design is to provide for the optimization of the burden and gas flow with a consideration of the potential raw material and operating conditions for the furnace throughout its campaign. BF design is required to integrate the properties of the shell, the cooling elements and refractory lining in order to ensure the well balanced overall operation of the BF complex. The choice of the right refractories and cooling systems at each zone of the BF is critical for successful, economic and, above all, safe operation of the BF. All the equipment necessary for smooth BF operation are to be integrated while designing a blast furnace. Major of these equipments are top charging equipment, cast house equipment (clay guns, tap hole drills, trough cover manipulators, tilting runners for iron and slag, bar changers, and jack dam drills etc.), tuyere stocks, various type of valves (e.g. hot blast valves, snort valve, bleeder valves, equalizing/relief valves, flow control valves, and isolation valves etc.), Different probes (e.g. above burden temperature probes, and sub-burden gas probes etc.), mechanical stock line recorders, moveable and fixed throat armor, stock line ignition lances, and profile meters etc. The design of BF should provide for equipment which has a proven reputation for reliability, durability, and high performance in the arduous conditions of the BF environment. The operation of a modern BF is quite complex and it needs necessary automation...

Glossary of Terms used for a Blast Furnace...

Glossary of Terms used for a Blast Furnace A cross section of a blast furnace showing nomenclature of different portion is shown in Fig 1 Fig 1 Cross section of a blast furnace Various term used to describe a blast furnace and its equipment are described below. Access tower – This tower is made of steel with platforms at various levels so that easy access can be made to various levels of the furnace. The tower is usually free standing. Alumina refractories – These refractories are used for lining of blast furnace. Alumina content of refractories varies depending on in which zone of the blast furnace they are used for lining. Annular space – It is the difference between the stock line radius and the large bell radius. Armor – These are the steel castings used for lining of the throat of the blast furnace. Bell – In blast furnaces with two bell charging system, two numbers of bells (small and big) are used to control the entry of charge materials in the blast furnace as well as to prevent escape of BF gas in the environment. These bells are of conical shape. Bell less top equipment – It is the furnace charging equipment which does not use the two bells but a rotating chute for furnace charging. Bell overhang – It is the vertical distance between the bottom of the large bell closed and the inner bell seat. Belly – It is the cylindrical portion of the blast furnace below the stack. It connects the upper bosh diameter with the largest diameter of the lower stack. Bellows – These are part of tuyere stock. It accommodates relative movement of blow pipe with respect to bustle pipe. Bellows can usually adjust movements up to...