1278516991595a1267106724867-brochure-o-wartsila-solutions-2015

ENGINES AND GENERATING SETSSCR SOLUTIONSSCR technology is based on the reduction of nitrogen oxides (NO X ) bymeans of a reductant (typically ammonia, generated from urea) at thesurface of a catalyst in a reactor.The temperature of the exhaust gas is thereby subject to constraintsboth on the upper and the lower side. The latter is particularly an issuewith fuels containing higher fractions of sulphur, such as those presentin typical heavy fuel oil (HFO) qualities available today, which calls foreven higher minimum temperatures in the catalyst.HIGH PRESSURE SCRThe SCR reactor is put on the high-pressure side, before the turbine.Integrating the SCR reactor before the turbine allows the reactor to bedesigned in the most compact way due to the higher density of theexhaust gas.Wärtsilä has developed and is systematically deploying highpressure SCR solutions for the complete 2-stroke engine portfolio withsingle and multi-turbocharger applications. Further, Wärtsilä allowsthird party brand high pressure SCR suppliers to interface to theengine provided interface specifications are met.ReactorMixing pipeBypassCollector pipeLOW PRESSURE SCRThe SCR reactor is put on the low-pressure side, after the turbine.Wärtsilä has developed a 2-stroke engine interface specificationsfor low pressure SCR applications that complies with the known lowpressure SCR system providers. Low pressure SCR is typically largerin volume and has the advantage of being less complicated to integrateinto the exhaust stream.86