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...