Catalyst for a DeNOx-application and a process for selective catalytic reduction of nitrogen oxides

Simple SummaryContent extracted from patent full text and abstract with AI.

This patent describes a novel catalyst for the selective catalytic reduction (SCR) of nitrogen oxides (NOx) from exhaust gases, particularly from combustion engines. The catalyst is composed of cerium oxide (CeO2) and niobium oxide (Nb2O5), both present at significant levels (at least 10% by weight each), and can be enhanced with additional dopants or mixed with zirconia for greater thermal stability. The catalyst exhibits excellent thermal resistance, high activity over a wide temperature range, and superior resistance to sulfur poisoning, thereby allowing efficient removal of NOx emissions using ammonia as a reducing agent (NH3-SCR process).

Use CasesContent extracted from patent full text and abstract with AI.

• After-treatment of exhaust gases in diesel and lean-burn gasoline engines to reduce NOx emissions.
• Industrial flue gas treatment for power plants, factories, and chemical processing plants with NOx emissions.
• Retrofit or replacement of conventional vanadia-based SCR catalysts in existing DeNOx systems to improve durability and efficiency.
• Development of catalytic converters for future vehicle emission standards requiring higher NOx removal and thermal stability.
• Use in stationary or mobile sources where high resistance to thermal aging and sulfur poisoning is needed.

BenefitsContent extracted from patent full text and abstract with AI.

• High conversion efficiency of NOx to nitrogen over a broad operational temperature range (150–550°C).
• Excellent thermal stability, maintaining performance even after prolonged high-temperature exposure (up to 800°C).
• Superior resistance to sulfur poisoning, enabling use in environments with sulfur-containing fuels or exhaust gases.
• Low formation of undesirable by-products like N2O during the SCR process.
• Catalyst can be tailored (form, composition, and method of application) for various industrial and environmental applications.
• Reduced dependency on vanadium, which has volatility and toxicity concerns in conventional SCR catalysts.

Technical Classifications (CPCs)

Inventors & Applicants

Patent Abstract

When summarizing the prior art, it is an objective of the present invention to provide a NH 3 -SCR catalyst which features excellent thermal stability and resistance towards sulfur poisoning. Further, a process for the selective catalytic conversion (SCR) of nitrogen oxides to nitrogen shall be provided excelling at high conversion rates over a broad width of reaction temperatures and at high catalyst lifetime. With respect to the catalyst this objective is achieved according to the present invention by a catalyst for a SCR-DeNOx-application having a catalytic active component; said catalytic active component comprises cerium oxide and niobium oxide whereby the content of cerium oxide is at least 10 wt% and the content of niobium oxide is at least 10 wt%. With respect to the process for the SCR of nitrogen oxides this objective is achieved according to the present invention by a process for a SCR of nitrogen oxides comprised in an exhaust gas of a combustion machine/engine or any other NOx source comprising the step of bringing the nitrogen oxides into contact with a catalyst as given in the claims 1 to 11. Preferably this process is carried out at elevated temperatures in the range from 150 to 550 °C, at pressure in the range from 10 3 to 10 5 hPa and at an gas hourly space velocity (GHSV) in the range from 5*10 3 to 10 5 h -1 .