Air pollution control – Control of particulate emissions Aug28

Air pollution control – Control of particulate emissions...

 Air pollution control – Control of particulate emissions Steel plant has many metallurgical processes which take place at high temperatures. Further many of these processes handle raw materials some of them are in the form of fines. Hence all these processes are prone to emit pollutant gases and particulate matter into the atmosphere. This in turn affects the quality of air around the plant. In order to improve and protect the quality of air, different pollution control devices are used for reduction of the emissions. Earlier for many years, pollution control equipments were used only for those processes where the pollutants amounts were very high or they were toxic in nature. These equipments were also earlier used where they had some recovery value. But today, with the environment laws becoming more and more tighter and with the increasing concerns of the society regarding the environment, it has become necessary for the steel industry to look into its emissions and install equipments in all the areas to reduce the emissions to minimum possible levels. The emission control equipments are basically of two types (i) particulate emission control equipments and (ii) gaseous emission control equipment. This article describes the particulate emission control systems. All particulate emission control equipments collects particulate matter by mechanisms involving an applied force. Various particulate equipments are settling chambers, cyclones, bagfilters and electrostatic precipitators. The mechanisms of dust removal in these equipments and the applied force are given in Fig. 1 Fig 1 Mechanisms of dust removals Settling chambers  Settling chambers was one of the first devices used to control the particulate emissions. However it is very rarely used today since its effectiveness in collecting particles is very low. The collection force in settling chamber is gravity. Large particles moving slow enough...