Why use Adblue and not use 100% Urea?

Thread starter James125
Start date Sep 13, 2013

AI Thread Summary

SCR systems use Adblue, a 33% urea solution, because ammonia is the required reactant for effective emissions reduction, not pure urea. Using 100% urea would not provide sufficient water for the necessary chemical reactions to occur in time. Urea is a solid, and its solubility limits its effectiveness in high concentrations. The formulation of Adblue ensures optimal performance and efficiency in reducing nitrogen oxide emissions. Therefore, the use of Adblue over 100% urea is essential for proper SCR function.

Sep 13, 2013

James125

Hello all

I am puzzled as to why SCR uses Adblue solution which is only 33% Urea. Why not use 100% Urea minimise fill ups and weight?

Thanks

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Sep 13, 2013

xxChrisxx

Becuase it's ammonia that is needed, not urea. You don't have enough water floating round to react in time. So you are injecting both reactants.

Sep 13, 2013

James125

Stupid question really Urea is a solid. It's solubility in water is 107.9 g/100 ml @ 20 °C. Presumably 33% at -10C or something.

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