Management of Greenhouse Gas Emissions in Integrated Steel Plant...

Management of Greenhouse Gas Emissions in Integrated Steel Plant Major constituents of greenhouse gases are carbon di oxide (CO2), methane (CH4), nitrous oxide (N2O), various fluorocarbons, sulphur hexafluoride, halons, and ozone in troposphere. Each of these gases has a different greenhouse warming potential (GWP) and their effects on atmosphere are not in direct proportion to their quantity of emissions. The GWP of a greenhouse gas is a measure which indicates of how much a given mass of gas contributes to the global warming. The GWPs of different greenhouse gases are given on a relative scale. This scale compares the GWP of the gas in question to the GWP of carbon di oxide gas which is considered as 1.0. Over 100 years of time horizon the GWP of methane is 21, whereas the GWP of nitrous oxide is 310 (Fig 1). Hydro fluorocarbons (HFC) which are used in some of the air conditioning systems of the steel plant have a GWP of up to 11700. Sulfur hexafluoride (SF6) used in some of the circuit breakers of the electrical transmission system of the steel plant has a GWP of up to 23900. Fig 1 Global warming potential of greenhouse gases The manufacture of iron and steel is an energy intensive activity that generates carbon dioxide, methane, and nitrous oxide emissions at various stages during the production process. Although CO2 is easily the main GHG emitted from an integrated iron and steel plant, N2O and CH4 emissions are not necessarily be small. The greenhouse gas which is the most relevant from the steel plant is CO2. The Steel Industry represents 6 % to 7 % of global anthropogenic CO2 emissions according to the Intergovernmental Panel for Climate Change (IPCC), but only 4 % to 5 % according...