Nett Technologies Inc., Mississauga ON, announced that its BlueMAX 300D Selective Catalytic Reduction (SCR) system has been verified as the first of its kind by the U.S. Environmental Protection Agency (EPA).
Nett’s BlueMAX 300D SCR is an emission control system that has been designed to reduce nitrogen oxides (NOx) emissions by at least 80% from medium- and heavy-duty diesel engines between 75 and 560kW (100-750 hp) in portable and stationary applications like diesel generator sets, pumps and compressors. The system also has the added benefit of reducing criteria emissions of carbon monoxide (CO) and hydrocarbons (HC) by at least 90% and particulate matter (PM) by at least 25%. This product is especially well suited for the known ozone nonattainment areas where controlling NOx will help individual states to adopt appropriate state implementation plans (SIPs) under the Clean Air Act.
The unit uses a urea control strategy that relies on NOx concentration measurements by a sensor. Based on the sensor signal, in combination with an engine mass air flow (MAF) sensor and temperature sensor, the necessary urea dosing rate is calculated by the control algorithm.
NOx is reduced by the SCR catalyst through chemical reactions with ammonia produced by the decomposition of urea. The urea solution is injected upstream of the SCR catalyst with the assistance of compressed air which helps improve urea atomization. Mixing of urea with exhaust gases is further enhanced through a static mixer upstream of the catalyst. Through a combination of thermal and catalytic processes, urea decomposes producing ammonia, which is available for reactions with NOx. Ammonia that is not used in the reaction is oxidized by a downstream ammonia slip catalyst.
The BlueMAX 300D SCR system incorporates a notification alarm box providing error code information related to basic functionality of the SCR as well as a data logger recording system providing SCR inlet temperature, inlet/outlet NOx concentration, urea dosing rate, intake MAF, urea tank temperature and error codes for low urea quality and low NOx reduction. The data logger also alerts the operator when the urea tank requires filling. This system will function at temperatures below 11ºC, which is the freezing point for urea, with the aid of an included heating system.