SCR Urea Consumption

Urea (as 32.5 % AdBlue solution) consumption for a selective-catalytic-reduction NOx aftertreatment.

EmissionsSCR

Engine powerkWOperating hourshEngine-out NOxg/kWhTarget tailpipe NOx (Tier III)g/kWhN:S ratio - Moles of NH₃ per mole of NOx reduced. 1.0 stoichiometric; 1.05 to avoid slip.

NOx reduced: 106.00kg

Pure urea: 145.17kg

AdBlue (32.5 %): 446.69kg

Changing the inputs requires JavaScript. The calculator above shows its default inputs and result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

m_\text{urea} = m_{NO_x} \cdot \frac{60}{46} \cdot \text{NSR}, \quad m_\text{AdBlue} = m_\text{urea} / 0.325

Symbol	Meaning	Unit
$m_{NO_x}$	Mass of NOx reduced	kg
$NSR$	N:NO_x molar ratio
$60 / 46$	Urea / NO₂ mole ratio

Source: MEPC.76(40) - SCR system requirements; ISO 22241 - AdBlue quality

In short

Urea (as 32.

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