How Catalytic converter reduces the harmful pollutants

                          The most effective treatment for reducing engine emissions is the catalytic converter, found on most automobiles and other modern engines of medium or large size. A catalytic converter is a chamber mounted in the flow system through which the exhaust gases pass through. These chambers contain catalytic material, which promotes the oxidation of the emissions contained in the exhaust flow. Generally, catalytic converters are called three-way converters because they are used to reduce the concentration of CO, HC, and NOX in the exhaust. A catalytic is a substance that accelerates a chemical reaction by lowering the energy needed for it to proceed. It is consumed in the reaction and so functions indefinitely unless degraded by heat, age, contaminants, or other factors.


                           Aim of the catalytic converter is to chemically treat the pollutants and convert them into harmless gases like CO to CO2, HC to H2O and splitting of NO to N2 and O2. A catalytic is a material that enhances chemical change without entering into a chemical reaction. The material which is used as catalysts is platinum, palladium, rhodium, etc.

                           The chemical reaction of conversion of CO to CO2 and HC to H2o, which normally takes place at temperatures of 500 degrees centigrade to 600-degree centigrade, occurs at 300-degree centigrade to 350-degree centigrade in the presence of a catalyst. The suits as sending air (oxygen) to exhaust may not convert CO and HC as the air will be at lower temperature and the temperature of exhaust also comes down quickly while passing through the exhaust tube from the exhaust manifold.


                            Platinum and Palladium are good catalysts for conversion of CO and HC and rhodium is used for the reduction of NOx. The catalytic converter is a tubular device integrated into the exhaust system. A catalytic converter is filled with a thin-walled mesh matrix coated with catalysis. as the exhaust gases pass through this, HC and CO get converted to H2O and CO2. When the mesh is coated with Rhodium, NOX is reduced to N2 and O2. Since all the three major pollutants, CO, HC, and NOX are to be converted into unharmful substances, two wires mesh one coated with platinum and other with Rhodium are used in one converter only. Catalysts do not take part in chemical reaction their life is long, but if gasoline contains lead, then the mesh gets coated with this poisonous lead and converter becomes, useless. Therefore, automobiles fitted with catalytic converter should always use unleaded fuel.

No comments