Engineering Calculators

SCR Urea Consumption

This calculator computes the amount of urea solution (diesel exhaust fluid, DEF) that is required to achieve a given conversion of NOx emissions over an SCR catalyst. The calculation assumes that all urea becomes decomposed to ammonia, which reacts with NOx according to the “standard” and/or “fast” SCR reactions.

Input Data

Enter the required input data and press the “Calculate” button to do the calculation. An asterisk will appear if your data is out of range.

NOx at SCR inlet
g/kWh
NOx conversion
%
DEF concentration
% (m/m)
Fuel consumption (BSFC)
g/kWh
Results
NOx at SCR outlet
g/kWh
NH3 consumption
g/kWh
NH2CONH2 consumption
g/kWh
DEF consumption
g/kWh
DEF / fuel (by mass)
% (m/m)
DEF density at 20°C
kg/m3
DEF / fuel (by volume)
% (v/v)