Innovative Diesel Exhaust Gas Aftertreatment for NO - Reduction

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1 Innovative Diesel Exhaust Gas Aftertreatment for NO - Reduction x SCR and SCRi TM Selective Catalytic Reduction An effective SCR system requires different catalyst substrates for pre-oxidator, evaporation, hydrolysis, reduction and the prevention of ammonia slip. By using different structures the substrates are optimally adapted to each specific function.

2 SCR METALIT Substrates Optimised Structures for the Processing Steps Due to their combustion processes with excess air economical diesel engines must use a process of selective catalytic reduction using urea to reduce NOx emissions. The important processing steps involved require special catalysts. Structured substrates offer an optimal solution, which meets all efficiency requirements. Advantages: - Optimum adaptation to the function of the relevant component by using differently structured substrates - This results in the best possible ratio between the highest degree of efficiency and the smallest space requirement - Uniform use of the entire catalyst volume ensures optimum durability - Utilisation of the excellent properties typical of METALIT, such as canning and load capacity SCR System NO formation 2 Selective NOx reduction NH 3slip prevention Oxicat SCR - Cat Ad Blue NO 2 formation: nitrogen oxide + oxygen nitrogen dioxide Ideal ratio of NO:NO2 (NO) (O2) (NO2) is 50 / 50 % NH 3 generation: urea + water ammonia + carbon dioxide ([NH2]2CO) (H2O) (NH3) (CO2) NO x reduction: nitrogen oxide + ammonia nitrogen + water (NO + NO2) (NH3) (N2) (H2O) NH 3 slip elimin.: ammonia + oxygen nitrogen + water If required: (NH 3 ) (O2) (N2) (H2O) prevention of ammonia slip

3 Structured Metal Substrates with Customised Functions Reduction of volume with oxidation catalyst by using LS structure: - HC and CO efficiency stay at high level - NO 2 formation is increased although volume reduction of substrate flat channel (3,8 litre) 300/600 LS (2,1 litre) 65% [%] 50 0 CO/HC Emission NO 2-formation Mixer structure in hydrolysis catalyst Channels with blade-like incisions and perforated intermediate layers enable an intensive mass transfer and mixing process between the individual channels. LS and LS/PE structure in reduction catalysts A so-called selective catalytic reduction (SCR) takes place in the reduction catalyst. The use of structured and turbulence causing metalites with LS and LS/PE design in particular leads to signi- This provides optimum atomization and equal distribution of the injected reduction agent ficantly increased conversion rates compared to conventional substrates. In the channels of these structures the counter corrugation repeatedly generates a turbulent inlet flow pattern with a high degree of mass transfer to the active channel wall. The perforated flat layers permit flow equalisation between the channels, which leads to optimum utilisation of the entire substrate cross-section.

4 Structured Metal Substrates with Customised Functions LS/PE-structure in hydrolysis catalyst: A so-called selective catalytic reduction (SCR) takes place in the reduction catalyst. The use of structured and turbulent metalites with LS and LS/PE design in particular leads to significantly increased conversion rates compared to conventional substrates. In the channels of these structures the counter corrugation repeatedly generates a turbulent inlet flow pattern with a high degree of mass transfer to the active channel wall. The perforated flat layers (PE) permit flow equalisation between the channels, which leads to optimum utilisation of the entire substrate crosssection. Improvement of NOx-conversion rate by LS/PE-structure NOx-Conversion [%] with alpha = % flatt channel (24 litre) LS-System (20 litre) 25% 0 220/ / / / / /1270 temperature [ C] / exhaust mass flow [kg/h]

5 Further development: The SCRi TM System: Bonus reduction of fuel consumption and CO2 emissions! Oxicat PM-METALIT SCR-Cat Ad Blue LS- and PE-Design TM PM-METALIT LS-Design TM - PM-METALIT in double function: Partial flow filtration and hydrolysis catalyst as mixer. SCRi TM technology combines the PM-METALIT, tried and tested in serial applications and as a retrofit, with an SCR system based on turbulence generating metal substrates. Placement of the PM-METALIT between the urea injection and reduction catalytic converter stages does not adversely affect either its filtering performance or SCR efficiency. The oxidation catalytic converter fitted before the system - ideally of LS or LS plus PE Design - generates NO2 which is - SCR-catalyst behind continuous PM-filtration. Turbulent structures allow more compact systems. needed for continuous particle reduction in the filter and for rapid SCR reaction particularly in colder sections of the test cycles. The well-known low backpressure of metallic substrates and the extremely compact installed size of SCRi TM using structured foils for oxidation converter and reduction converter ensure low exhaust back-pressure and also assist in reducing CO2 emissions.

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