History of Basic Oxygen Steelmaking Dec16

History of Basic Oxygen Steelmaking...

History of Basic Oxygen Steelmaking  Basic oxygen steelmaking (BOS) is the process of making steel by blowing pure oxygen (O2) in a liquid metal bath contained in a vessel which is known as basic oxygen furnace (BOF), LD converter, or simply converter. The history of steelmaking began in the 19th century, when Reaumur of France in 1772, Kelly of the United States in 1850 and Bessemer of Britain in 1856 discovered how to improve on pig iron by controlling the carbon content of iron alloys, which thus truly become steels. While Reaumur, a chemist, was driven by scientific curiosity, but Kerry and Bessemer being engineers, were responding to the need for larger quantities and better qualities of steel which the industrial revolution, with its looms, steam engines, machines and railroads, had created. This had started a dialectical relationship between science and technology and the basic concepts of refining hot metal (pig iron) by oxidizing carbon (C) in a liquid bath were invented at that time. This was a radical change from the gas-solid reaction in the shaft furnaces, the predecessors of blast furnaces which reduce iron ore with charcoal, or from the puddling of iron which was a forging and refining technology carried out in the solid state and which has no equivalent in the present time. The intensity of innovations which at the second half of the 19th century was impressive and it brought a paradigm shift. Steel making by Bessemer converter came into existence in 1856, the open hearth furnace, which can melt scrap in addition to refining hot metal, was discovered nine years only after the Bessemer converter in 1865, and the basic Thomas converter twelve years later in 1877.  The Thomas converter was using air for the refining of the...

Basic Oxygen Furnace Gas Recovery and Cleaning System May20

Basic Oxygen Furnace Gas Recovery and Cleaning System...

Basic Oxygen Furnace Gas Recovery and Cleaning System During the process of steel making in the basic oxygen furnace (BOF), oxygen is blown in the charge mix and due to chemical reactions taking place in the vessel, a large amount of gas at high temperature and rich in carbon mono oxide (CO) comes out through the mouth of the converter. At this stage this gas is very hot (Temperature 950 deg C or greater) and dust laden. This gas is known as LD gas or converter gas. The composition of the gas varies from the start to the end of the blow and is a function of the blow time. The main constituents of converter gas are carbon mono oxide, carbon di oxide (CO2), oxygen (O2) and nitrogen (N2). Typical composition of the by volume is CO – 55 to 60 %, CO2 – 12 to 18 % oxygen 0.1 to 0.3 % and rest is N2. The first converters were put into operation in November 1952 (VOEST in Linz) and May 1953 (ÖAMG, Donawitz). During the early years of the LD converter process, the top gas was completely burnt at the converter mouth through the open hood and then cooled in the stack either indirectly with water or by evaporation cooling system.  At that time around 300 Kg of steam and 250 Cu m of off gas per ton of crude steel were produced. Environmental aspects were a serious challenge for the converter process at the time it was industrially implemented in 1950s. The fineness of the dusts in the converter off gas forced the suppliers of the process to develop new dedusting systems. 1 gram of converter dust has a visible surface area of between 300 to 500 Sq m. In order...