Catalytic removal of carbon monoxide, unburned hydrocarbons and nitrogen oxides from automotive exhaust gas

• US 3,895,093 A
• Filed: 01/31/1974
• Issued: 07/15/1975
• Est. Priority Date: 02/01/1973
• Status: Expired due to Term

• Current Assignee: Gunter Weidenbach, Karl Hermann Koepernik
• Original Assignee: Gunter Weidenbach, Karl Hermann Koepernik
• Inventors: Weidenbach, Gunter, Koepernik, Karl Hermann
• Primary Examiner(s): Peters, G. O.
• Application Number:
  US05/438,247
• Time in Patent Office: 530 Days
• Field of Search: 423/213.5,213.7 60/301 252/466
• US Class Current: 423/213.5
• CPC Class Codes: B01D 2255/1021 Platinum
• CPC Class Codes: B01D 2255/1025 Rhodium
• CPC Class Codes: B01D 2255/1026 Ruthenium
• CPC Class Codes: B01D 53/945 characterised by a specific catalyst
• CPC Class Codes: B01J 23/6567 Rhenium
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Disclosed are a process and catalyst for catalytically removing carbon monoxide, incompletely burned hydrocarbons and nitrogen oxides from an automotive exhaust gas in a single stage catalytic converter. The ratio of fuel and air introduced to an engine is controlled in a particular manner and there is employed a catalyst which is capable of promoting the simultaneous oxidative conversion of 90% of the carbon monoxide and hydrocarbons and reductive conversion of at least 90% of the nitrogen oxides. A preferred catalyst is one comprising a mixture of platinum, ruthenium, rhodium and rhenium.

Claims

1. A process for catalytically removing carbon monoxide, incompletely burned hydrocarbons and nitrogen oxides from an automotive exhaust gas, having a q-value of between 0.8 and 1.2 wherein

2. The process as defined by claim 1, wherein the ratio of platinum, ruthenium, rhodium and rhenium is between about 1:

1;

1;

1 and 1;

0.25;

0.25;

0.25.

3. The process as defined by claim 1, wherein said catalyst comprises a non rusting, scale-free, highly heat resistant metallic skeleton having thereon an elastic priming layer comprising aluminum silicate, an outer layer comprising a catalytically active alumina and 0.01 to 0.5 % by weight each of platinum, ruthenium, rhodium and rhenium distributed on said carrier material.

4. The process as defined by claim 1, wherein said catalyst comprises a heat resistant ceramic honeycomb structure having thereon a layer comprising a catalytically active alumina and 0.01 to 0.5 % by weight each of platinum, ruthenium, rhodium and rhenium distributed on said carrier material.

5. The process as defined by claim 1, wherein said catalyst comprises a particulate catalyst carrier consisting of catalytically active alumina or aluminum silicate having distributed thereon a mixture from about 0.01 to 0.5 % by weight each of platinum, ruthenium, rhodium and rhenium.

6. The process as defined by claim 1, wherein said catalyst has been reduced prior to being contacted with said exhaust gas.

7. THE PROCESS AS DEFINED BY CLAIM I, WHEREIN SAID PLATINUM, RUTHENIUM, RHODIUM AND RHENIUM ARE EACH PRESENT IN AN AMOUNT BETWEEN ABOUT 0.05 AND 0.2% BY WEIGHT