Desulphurization of Hot Metal Oct16

Desulphurization of Hot Metal...

Desulphurization of Hot Metal Removal of sulphur from hot metal is called desulphurization of hot metal. Sulphur is a desirable element in steel when good machinability is required from the steel product. However it is an unwanted element in most of the applications of steel due to the following reasons. Sulphur affects both internal and surface quality of steel Sulphur contributes to the steel brittleness and when it exists in sulphide phase it acts as a stress raiser in steel products. It forms undesirable sulphides which promotes granular weakness and cracks in steel during solidification. It has adverse effect on the mechanical properties. It lowers the melting point and intergranular strength and cohesion of steel. Unlike other impurities which are removed from the hot metal by oxidation in the oxygen converter, the most economic method of removing sulphur from the hot metal is by reduction either in the transfer ladle or in the charging ladle, before it is charged in the converter. A number of technologies have been developed for the external desulphurization of hot metal but all of them have the basic requirement of a reagent and a method of mixing. The difference between the technologies used is the properties of the reagents, the effectiveness of the reagent to remove sulphur and the effectiveness of the mixing method to get the reagent into solution. . Also the effectiveness of hot metal desulphurization is inversely proportional to the desulphurization reagent injection rate. The most popular desulphurizing process today is deep injection of desulphurizing agent in the hot metal. Desulphurization process Dip lance process is the most economical, effective and reliable method of desulphurization hot metal. It consists of pneumatic injection of fine grained desulphurization reagent into the hot metal with high dosing precision via...

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...

Energy Management in a Steel Plant...

Energy Management in a Steel Plant Iron and steel industry is the largest consumer of energy among all industrial sectors. Energy conservation in steel industry is crucial for its competitiveness, sustainability and minimization of environmental impacts including green house gas emissions and better resource management. As per World Steel Association, energy costs represent around 20 % to 25 % of the total input of steel plants. Energy cost cutting and energy efficiency improvements are the most important topics of control for the steel plant management.  Energy management provides the following opportunities in a steel plant. It provides opportunities to decrease the energy intensity per ton of crude steel It provides opportunities to adopt best or good practices for utilization of energy sources more effectively It provides opportunities for using best or good practices for recovery of heat and gas energy wherever practical. It enables the plants to develop plans for reduction of plant’s energy intensity It makes plant to carry out prioritization of those investments which have biggest impact on the energy efficiency. Energy management efforts, which aim to reduce energy use, are a must as well as a key element for a steel plant’s energy management programme. Twin approach for energy management in a steel plant is desirable and necessary. Energy management programme can be system based through implementation of ISO 50001-2011 standard as well as it can be a technical approach based on real time information obtained from process monitoring and control systems and on production plans received from production planning systems. While the first approach is a management approach which streamlines all the systems connected with energy use and energy conservation, the second approach provides information on actual and planned energy indicators of production, distribution and consumption on real time basis...

Blast Furnace Top Charging Systems Oct11

Blast Furnace Top Charging Systems...

Blast Furnace Top Charging Systems In earlier days, blast furnace (BF) top used to be open with the gas from the furnace escaping into the atmosphere and burning, causing environmental issues while wasting considerable energy. By 1850 as the furnace size increased, the furnace top could be closed. A single bell and hopper arrangement could be used for charging the furnace that kept the top of the furnace closed and sealed. The single bell and hopper system permitted large quantity of gas to escape every time the bell was opened. Soon a second bell and hopper was added above the first so that a gas tight space could be provided between the two bells to prevent the blast furnace gas escaping when the small bell was opened. The upper bell and hopper did not have to be as large as the lower one because several charges could be deposited through it on the lower bell and the upper bell could be closed before the lower bell was opened for dumping the charges in the furnace The two bell system continued to be the only charging system for the blast furnaces around the world till S.A. Paul Wurth in Luxembourg, developed bell less top (BLT) charging system and the first successful industrial application of BLT charging system was in 1972. Soon BLT charging system took over from two bell charging system since it provided a number of advantages to BF operators. During 2003, Siemens VAI introduced Gimbal concept of charging. This charging system has been successfully used for Corex and Finex processes for charging. The first application of Gimbal for charging a blast furnace was in 2009, when it has been used for C blast furnace of Tata steel. Two bell charging system The two...

Steel Wire Ropes

Steel Wire Ropes Steel wire rope, is also known as steel cable.  It is a type of rope which consists of several strands of steel wire laid (twisted) into a helix. Modern wire rope was invented by the German mining engineer Wilhelm Albert in the years between 1831 and 1834 for use in mining. It was quickly accepted because it proved superior to metal chains and ropes made of hemp which was used before. Wilhelm Albert’s first ropes consisted of three strands consisting of four wires each. Wire rope industry in India, which was founded very early, started with coconut fibre ropes, switched to jute fibre, on to ‘Manila’ ropes and then to steel ropes. With the change in the needs, the designing of the wire ropes also undergone major changes with respect to the core, overlay and the weight requirement etc. Wire rope is a machine which consists of a number of precise moving parts, designed and manufactured to bear a definite relation to one another. In fact, some wire ropes contain more moving parts than many complicated mechanisms. For example, a six strand wire rope, laid around and independent wire rope core each strand and core with 49 wires, contains a total of 343 individual wires. All these wires are to work together and move with respect to one another if the rope is to have the flexibility necessary for successful operation. Wire rope has three components (Fig 1) consisting of wires, strands and core. The basic unit of a wire rope is wire which is carefully processed and drawn from selected grades of steel to predetermined physical properties and sizes. A predetermined number of finished wires are helically laid together in a uniform geometric pattern to form a strand. The process is carried out with precision and...