Nitric Acid

The basic feedstock for many nitrogen-based fertilizers as well as for other chemicals like some plastics and explosives, is nitric acid, which is usually available in 60-68% concentration range (“weak nitric acid”). In the production of fertilizers nitric acid within 58-62% concentration is preferably used. Two different processes are available for the manufacture of weak nitric acid, depending on the operating pressures:

• mono pressure processes, and
• dual pressure processes

Mono pressure plants are less expensive compared to dual pressure ones but their operating costs (in terms of specific ammonia consumption and loss of catalyst) are slightly higher. Mono pressure plants are usually preferred up to 900 MTPD capacities (calculated as monohydrate).

Dual pressure plants are more sophisticated and are recommended in case the production is higher, as nowadays preferred by fertilizer producers. The investment cost is higher than a mono pressure plant, against better specific ammonia consumptions and lower loss of catalyst.

The selection of the best process is usually driven by the requirements of downstream users of nitric acid, the capacity of the plant, the cost of raw materials, catalysts and utility or it depends on local conditions or client demand. The typical operating range required is 70-110% of the nominal plant capacity.


The Nitric Acid Plants offered by CASALE PROJECT a.s. are based on process technology provided by its sister company Casale S.A. (Switzerland), which has acquired it from Borealis and that was formerly developed by Grande Paroisse S.A.


Key Features
• Wide flexibility, 70-110% of the nominal load
• Capacity: from 600 to 1500 MTPD
• Low specific consumption figures: 282-284 kg of ammonia per ton of acid
• High steam export: 600-700 kg per ton of acid
• Environmentaly friendly process: NOx and N2O emissions less than 100 ppmv

NA Hungary