Environment-friendly catalysts reduce emissions

High-performance catalyst manufacturer Clariant Catalysts has developed the EnviCat N2O catalyst, to remove nitrous oxide (N2O) and nitrogen oxide (NOx) gases almost entirely from the waste gases emitted by industrial plants.

N2O is a climate-changing gas, with an average life span of 114 years in the earth’s atmosphere. The effect of N2O as a greenhouse gas is about 300 times stronger than that of carbon dioxide.

“While N2O – commonly known as happy gas or laughing gas – presents environmental risks, NOx  can cause headaches, respiratory problems and even chronically reduced lung function in higher concentrations,” explains Clariant Catalyst technical sales manager Dr Jonathan Chetty.

The EnviCat N2O catalyst removes N2O and other nitrogen oxides from industrial emissions. It can remove N2O from the tail gas of nitric acid and adipic acid plants and renders other nitrogen oxides innocuous. It converts them into harmless molecules such as nitrogen, water and oxygen.

“The N2O is converted during two stages – the N2O is split into oxygen and nitrogen using the EnviCat N2O catalyst, then the nitrogen oxides are mixed with ammonia to produce harmless nitrogen and water,” notes Chetty.

He adds that the EnviCat N2O catalyst consists of porous, crystalline zeolites, which are minerals derived from aluminium silicate, into which more iron can be intercalated. N2O and other nitrogen oxides are passed through a catalyst bed at temperatures of between 300 °C and 500 °C that results in reduced emissions.

“Despite the health and environmental benefits of using a catalyst, the one notable downside is the startup capital that is required when adopting catalytic technology – or any other technology to improve air emissions. The present driver for employing this technology is more stringent legislation, but also the insight that a focus on long-term sustainability can ultimately result in strong reputational and economic benefits,” mentions Chetty.

Clariant Catalysts currently supplies a range of catalysts to South African refineries and chemicals businesses. “In addition to supporting a healthy and sustainable environment, we provide catalysts for the production of commodity chemicals and speciality products.”

Further, other EnviCat catalysts purify emissions from different chemical compounds, such as volatile organic compounds or carbon monoxide. These catalysts are suitable for use in, for example, the chemicals, food, printing and energy-production industries, where the emission of organic compounds is common.

In South Africa, Clariant’s catalysts play an important role in the industrial production of inorganic chemicals, such as ammonia and nitric acid; organic chemicals, such as methanol, ethanol or acetone; and petrochemicals, agrochemicals and plastics,” concludes Chetty.