How Does DEF Breakdown Pollutants?
SCR technology uses DEF as the reactant in the catalyst to break down harmful nitrogen oxide present in diesel exhaust. A typical SCR system consists of a decomposition reactor coupled with a SCR assembly. Engine exhaust enters the decomposition reactor where DEF is injected as a mist. Ammonia is formed when the DEF and exhaust mixture is vaporized as it enters the SCR assembly where the ammonia reacts with NOx breaking it down into nitrogen and water.
DEF is a solution of high purity urea and deionized water at a ratio of 32.5 to 67.5 percent and is manufactured to strict specifications. Deionized water is used in DEF because it does not contain dissolved minerals and other natural components as tap water does. The dissolved minerals behave as contaminants in an SCR system.
What Happens If Water Is Used Instead Of DEF?
If water accidentally enters the engine, it would stop running when engine sensors detect the water. Over the longer term, water may cause rust or other damage to the engine and associated piping. Water would not be effective in an SCR system because it does not contain ammonia, and therefore would not reduce the harmful pollutants in diesel exhaust to meet EPA emission standards. Tap water naturally contains dissolved metals and may cause significant damage to, or failure of, the SCR assembly would be costly to replace.
What Safeguards Help Prevent Damage To Engines?
Many safeguards have been included in new diesel truck design to prevent accidentally adding the wrong liquid to the DEF tank. DEF dispensers and the tank caps are blue to distinguish them from other fuel parts of the dispensing system. The DEF tank fill port is smaller in diameter than a diesel dispenser nozzle. A signal from the SCR system will alert the driver if a non-DEF fluid enters the SCR system.
Contact the fueling specialists at Innovative Fueling Solutions for answers to your DEF questions or for any other fueling needs you may have. We are leading the way in providing DEF equipment and dispensing systems to private and commercial fleet owners. Our offices are located in Amarillo, Texas and Clovis, New Mexico.