Emissions from Adipic Acid and Nitric Acid Production

Nitrous oxide (N2O) is generated as a by-product during the production of adipic acid and nitric acid. The main use for adipic acid is as a component of nylon-6/6; thus production trends are closely correlated with nylon consumption trends. Worldwide, there are very few adipic acid plants. The U.S. is a major producer with three companies in four locations accounting for approximately forty percent of world production. Other producing countries include Brazil, Canada, China, France, Germany, Italy, Japan, Korea, Singapore, Ukraine, and United Kingdom. Most of these countries have only one adipic acid plant. Nitric acid is used primarily to make synthetic commercial fertiliser. Worldwide, the number of nitric acid plants is somewhat uncertain. Estimates range from 255 to 600 plants (Choe et al., 1993; Bockman and Granli, 1994). In 1990, adipic acid production was the largest source of industrial N2O emissions. As of 1999, industrial sources report that all major adipic acid producers have implemented N2O abatement technologies (Reimer, 1999). As a result, nitric acid production is currently believed to be the largest industrial source of N2O emissions.