Adipic acid (C6H10O4) is a white crystalline solid used primarily as the main constituent of nylon (nylon- 6/6), representing about half of the nylon molecule. It is also used in the manufacture of some low- temperature synthetic lubricants, synthetic fibers, coatings, plastics, polyurethane resins, and plasticizers, and to give some imitation food products a tangy flavor.

Adipic acid is a dicarboxylic acid manufactured by a two-stage process. The first stage of manufacturing usually involves the oxidation of cyclohexane to form a cyclohexanone / cyclohexanol mixture. The second stage involves oxidizing this mixture with nitric acid to produce adipic acid. Nitrous oxide (N2O) is generated as a by-product of the nitric acid oxidation stage and is emitted in the waste gas stream.

Rhodia has a plant at ONSAN, South Korea that manufactures the second stage of the adipic acid production. The cyclohexanol / cyclohexanone feedstock comes for the major part from existing supply contracts; the complement depends on the availability of cyclohexanone and/or cyclohexanol on the market.

Currently, the waste gas stream from the adipic acid unit goes through a treatment process to recover the nitrogen oxides (NOx). Nitrous oxide remains unchanged through that treatment and is released with the off gases to the atmosphere. The emissions from the plant meet the current Korean regulation.

The project activity consists of the installation of a dedicated facility to convert at high temperature the nitrous oxide into nitrogen based on the process of thermal decomposition. A boiler which generates steam with the high-temperature flue gas coming from the thermal oxidizer will also be installed.

The installation of the decomposition facility will enable Rhodia Polyamide Co. Ltd to avoid N2O emissions (GHG emissions), which would in the absence of the project activity have been vented to the atmosphere. The installation of the decomposition facility would not only make Rhodia Polyamide Co. Ltd contribute to sustainable development by restricting the release of GHGs but will also give economic and technical benefits to the country by providing direct and in-direct employment and transfer of thermal decomposition technology to the country. CDM – Executive Board