SCR technology uses ammonia in the form of a urea-water solution (DEF/ AdBlue®) as a reducing agent for catalytic reactions. Particularly if an airless injector is used, the urea solution has a tendency to form deposits (urea crystallization) in the process of evaporation and decomposition into ammonia.
To prevent the build-up of deposits and to obtain good uniformity in the catalyst cell, an efficient mixer is needed. Particularly in limited-space applications and in real driving cycles that include slow driving with low loads, the high NOx reduction targets of today's regulations cannot be reached without efficient urea mixing. The key to solving mixing problems is to have an effective urea mixer, such as the Proventia SuperTornado™.
As a rule, the longer the mixing length is, the easier it is to achieve optimal urea mixing. In diesel engines, particularly in those applications that require a compact design, there is no space available for longer pipelines.
Proventia SuperTornado™ will allow injecting more urea solution at low temperatures and in minimal pipe lengths. Proventia SuperTornado™ mixer technology contributes to even ammonia (NH3) distribution and improves overall SCR performance by inducing turbulence and enhancing ammonia (NH3) mixing within the exhaust gas.
Proventia SuperTornado™ urea mixing technology is a flexible platform that can be used with various urea dosing systems to solve deposit problems and improve SCR performance in many applications with different engine sizes and in a variety of operating environments. The Proventia SuperTornado™ enables the design of compact EAT systems for applications that have limited space requirements. The system can be integrated with DPF substrates if the chosen emission strategy requires DPF.
Proventia designs the SuperTornado™ urea mixing technology to fit the customer's application and to meet any specific needs and provides support in dosing strategy calibration as well.
The Proventia SuperTornado™ urea mixer has two separate swirling concentric flows. Urea is injected into the central flow, where the small droplets evaporate and bigger droplets travel further down the mixer to where the two flows meet. When the droplets reach the stronger outer flow, the velocity difference between flow and droplet rises rapidly, resulting in a high evaporation rate. With SuperTornado™, evaporation and mixing is effective, leading to ammonia uniformity values exceeding 0.99, allowing more precise amounts of urea to be injected into the exhaust gas – even at lower temperatures – which eventually results in increased NOx reduction and the best possible use of SCR catalyst chemistry.
The greatest benefit from the mixing technology is for SCR performance and NOx reduction at low temperatures in real driving circumstances.
Vice President, Technology
arno [dot] amberla [at] proventia [dot] com
Senior Application Manager
toni [dot] kinnunen [at] proventia [dot] com
Vice President, Sales & Marketing
petri [dot] saari [at] proventia [dot] com