Fundamentals of Sulfate Species in Methane Combustion Catalyst Operation and Regeneration—A Simulated Exhaust Gas Study

Niko M Kinnunen,Mika Suvanto,Kauko Kallinen,Teuvo Maunula,Matthew Keenan

doi:10.3390/catal9050417

Abstract

Emission regulations and legislation inside the European Union (EU) have a target to reduce tailpipe emissions in the transportation sector. Exhaust gas aftertreatment systems play a key role in low emission vehicles, particularly when natural gas or bio-methane is used as the fuel. The main question for methane operating vehicles is the durability of the palladium-rich aftertreatment system. To improve the durability of the catalysts, a regeneration method involving an efficient removal of sulfur species needs to be developed and implemented on the vehicle. This paper tackles the topic and its issues from a fundamental point of view. This study showed that Al2(SO4)3 over Al2O3 support material inhibits re-oxidation of Pd to PdO, and thus hinders the formation of the low-temperature active phase, PdOx. The presence of Al2(SO4)3 increases light-off temperature, which may be due to a blocking of active sites. Overall, this study showed that research should also focus on support material development, not only active phase inspection. An active catalyst can always be developed, but the catalyst should have the ability to be regenerated.

Highlights

Current and future emission regulations and legislation of fossil fuels inside the European Union aspire to decrease the tailpipe emissions of transportation
The effect of Al2 (SO4 )3 (AS) on the performance of PdSO4 (PS) in complete methane oxidation is presented in Figure 1, together with the sulfur-poisoned modern methane combustion catalyst as a reference [20]
The role of Al2 (SO4 )3 on the regeneration of the low-temperature methane combustion catalyst was studied in the presence of simulated exhaust gas

Summary

Introduction

Current and future emission regulations and legislation of fossil fuels inside the European Union aspire to decrease the tailpipe emissions of transportation. The exhaust gas aftertreatment system plays a key role in low emission vehicles, and one of the main issues is its durability. Exhaust gas aftertreatment systems of heavy-duty applications in Europe already have a durability requirement, that is, 700,000 km, or seven years maximum [1]. Natural gas and bio-methane will be the generation alternative fuels in the transportation sector, generating low overall emissions. The gases emit less CO2 per energy equivalent compared to regular diesel fuel, which decreases their carbon footprint. A small amount of un-burnt methane, the main constituent of natural and bio-gas, always slips from an engine to its exhaust gas. Due to the higher global warming potential of methane, compared to CO2 , its emissions must be converted with a catalyst

Methods

Results

Conclusion