Catalytic oxidizers in automobiles and industry reduce toxic emissions by oxidizing carbon monoxide and hydrocarbons, while reducing oxides of nitrogen. They use platinum and palladium/rhodium as catalysts and cannot operate in the presence of lead. While they have improved over the years, reducing CO2 emissions remains difficult.
A catalytic oxidizer, or catalytic converter, is an automobile component found in the exhaust system. It oxidizes (burns) carbon monoxide and hydrocarbons, using platinum and palladium/rhodium as catalysts, while reducing (separates the oxygen atom rather than adding it) oxides of nitrogen to create nitrogen. This greatly reduces toxic tailpipe emissions and reduces smog.
Catalytic oxidizers became widespread after automobile emissions regulations were made nationwide mandatory in the US in 1968. They are now used in most cars around the world. Because catalytic oxidizers cannot operate in the presence of lead, their introduction caused leaded gasoline to be phased out. Catalytic oxidizers are also used in industrial processes to reduce harmful emissions, but their most common appearance is in automobiles.
Ideally, the byproducts of a car engine are just carbon dioxide, water, and some nitrogen. This is similar to the chemical production of animals. But in practice, the combustion process in an engine is never 100% efficient, leaving behind hot but unburned hydrocarbons. Prior to the 1960s, these emissions were allowed to escape into the atmosphere, until it was realized that they posed an environmental and public health hazard. Now, catalytic oxidizers installed in the tailpipe of an automobile rapidly oxidize a large percentage of the remaining unburned hydrocarbons, resulting in cleaner emissions. However, the speed at which catalytic oxidizers must operate to trap unburned hydrocarbons before they are blown out of the tailpipe places limits on the effectiveness of the oxidation process.
The quality of catalytic oxidizers has steadily increased over the years, resulting in ever cleaner cars. It is still difficult to reduce CO2 (carbon dioxide) emissions. CO2 cannot be oxidized into something more harmless, and it is a known greenhouse gas, which contributes to global warming.
Catalytic oxidizers in automobiles operate at a relatively high temperature, around 750°F (400°C). In industry, catalytic converters can be dozens of times larger than those used in automobiles, and several times hotter. Standard catalytic oxidizer subcomponents include a line burner, catalyst bed, and heat exchanger. The catalyst bed is generally in the form of ceramic honeycomb or ceramic beads coated in the catalyst.
Protect your devices with Threat Protection by NordVPN
