Nitrous Oxide (N2O) is an undesired by-product of the nitric acid (HNO3) production process at the synthetic fertilizer production facility.

In order to produce nitric acid, ammonia (NH3) is oxidized into NO—desired product1—with air on precious metal catalyst gauzes (usually platinum-rhodium alloys) in the ammonia burner of the nitric acid plants. Through this process, some amount of undesired N2 and N2O are formed as the gauzes’ selective capability drop over time.

N2O is not a toxic substance and is not regulated in Pakistan. Therefore, it is released to atmosphere without any recovery or any specific treatment at the targeted facility of the Pakarab Fertilizer Ltd (PVT).

N2O is reduced if non-selective catalytic reduction (NSCR) equipment is introduced in order to reduce NOX emissions. However, the NOX emissions level at the targeted facility is and expected to be below the local regulatory level. Therefore, it does not currently install or has no plan to install NSCR in the foreseeable future.

There is no economic incentive to recover and utilize or sell N2O as a product, technically and economically, except for CERs.

In addition, the project does not result in increasing the HNO3 production. Therefore, without CERs, PVT is going to release N2O emissions under its normal operation (i.e., continuation of the current practice).

Currently, around (82.5 × 2 + 28.0) × 103 Nm3/hr flue gas per line from around 434,000 t HNO3/yr production process (three lines) is emitted. The project is to introduce catalytic DeN2O equipment (Regenerative Catalytic System) at the tail point before release to the atmosphere. The technologies are provided by N.E. Chemcat (catalyst) and Sumiko Eco-Engineering (engineering). It is expected that the equipment can decompose more than 90% of the N2O, which would be emitted otherwise.2

The project also installs DeNOX equipment (SCR-type) and reduces most of the NOX emissions as well, although it is not necessary because the host company complies with the NOX regulation and would be continued to comply with it.

In addition to reduce N2O emissions, the project transfers a clean technology which is not yet widely commercialized even in industrialized countries. It also includes the training course for operation of the DeN2O equipment and also for accurate monitoring. The local employment will be created through the direct/indirect economical effects through the project activity.