Boosting Existing Nitric Acid Production

Keywords: Nitric acid, Revamping, Increasing compressor capacity, Plant efficiency.

Introduction:

In the last few decades no revolutionary process developments in the nitric acid industry have been introduced. Nitric acid plants built 50 years ago were exclusively operated at atmospheric pressure. Recent developments have mainly been the reduction of the production costs by optimising energy utilisation, the reduction of investment costs and optimisation of the pressure levels to meet environmental requirements. In fact, the specific ammonia consumption and catalyst expenses are higher today than in plants built in the thirties.

Our investigations indicate that even replacement of 3 to 6 old nitric acid plants with a new large unit does not today give sufficient return on investment. It is therefore important to be able to extend the capacity of existing nitric acid plants, as they very often are the bottleneck of the nitrate-containing fertiliser production. This paper will focus on different possibilities to increase the nitric acid production and give examples from some of our modifications.

E Faried MSc (Chem E), L Hjørnevik MSc (Chem E) and G Kongshaug MSc (Chem E).

Norsk Hydro Research Centre, Porsgrunn, Norway.

20 Pages, 9 Figures, 2 Tables.