Journal
FUEL
Volume 161, Issue -, Pages 269-277Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.fuel.2015.08.061
Keywords
Urea-SCR spray; Cross-flow; Mixture uniformity; NH3-distribution
Categories
Funding
- Environmental Technology Promotion of the Swiss Federal Office for the Environment (FOEN) - BAFU Project DeMiCo
- Liebherr Machines Bulle S.A., Bullet Switzerland
- Swiss Oil Association (Forschungsfonds der Erdoel-Vereinigung), Zurich, Switzerland
Ask authors/readers for more resources
Selective catalytic reduction with urea-derived ammonia is the method of choice for NOx abatement in diesel engine exhaust. Pressure-driven or air-assisted atomization of aqueous urea are the main methods taken into consideration and greatly determine urea decomposition, mixture formation and SCR performance. This experimental study compares the spray behavior of two commercially available urea water solution injectors under various cross-flows. Shadow imaging and planar Mie scattering captured the spray phenomenology, while phase Doppler anemometry provided droplet sizes and velocities. Distributions of urea and decomposition products were determined from samples by high pressure liquid chromatography. Fourier-transform infrared spectroscopy measurements downstream of a catalyst provided ammonia distributions as well as NOx reduction characteristics. Pressure-driven urea-distributions are shown to be governed by the extensive volume fraction in the largest droplets. These are affected only slightly by the flow and their impingement is of primary interest. This resulted in poor mixture formation across all flow conditions. In contrast, distribution of the smaller droplets created by air-assisted atomization depends mostly on the turbulence and vorticity induced by the injector air-flow. Uniformity was excellent under low flow conditions but reduced at higher cross-flows. Urea and consequent non-uniform ammonia distribution led to inherent NOx conversion deficiency and NH3-slip. For identical overall NH3/NOx ratios in the feed the pressure-driven injector results in lower NOx conversion and higher NH3-slip in respect to the air-assisted injector. (C) 2015 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available