Stabilizing Nitrous Oxide in Strong Nitric Acid for Industrial Purposes

Abstract

The nitrous oxide is determined by the content of (NOx) in the strong nitric acid, the increase of nitrous oxide by the way of either acid decomposition or temperature modification[1], [2] influence the safe production of military products and environmental pollutions[3]. The required specifications of the acids should meet the requirement of desired industry and safety during the transportations from site to site and storage. If the specifications (nitrous oxide) changed rapidly during transportation, decomposition takes place. It is believed that the Sudanese ambient temperature plays the main role. The strong nitric acid that has been stored for long time and transferred away will thermally and catalytically decompose and specifications will change. This study aims to develop a set of preliminary guide lines and recommendations for stabilizing the nitrous oxide (HNO2) in strong nitric acid. The equilibrium relations between acids systems (Nitrous oxide NOx expressed by "nitrous acid HNO2 concentration" and strong nitric acid HNO3) were reviewed and explained. The effects of Sudan ambient temperatures on acceleration of nitrous oxide (HNO2) in strong nitric acid, determine the optimum cooling temperature to slow the decomposition and to stabilize the nitrous oxide were investigated. This is done through incubation of three samples of strong nitric acid (97.5%) at the temperatures 20°C, 25°C and 30°C. Laboratory analysis was done to observe the nitrous oxide exit rate as function of temperatures, concentration of strong nitric acid within four days, Table I, II, III and Fig. 2, 4, 6 show the obtained experimental data. A noticeable increase of nitrous oxide at respective temperatures (20 0C, 25 0C, 30 0C) at the beginning was observed then the curve levels after three days’ incubation. It is concluded that (200C) is the higher temperature at which the strong nitric acid is either stored or transported. Hence it is the optimum temperature to slow the decomposition and stabilize the nitrous oxide. Recommendations for checking Strong Nitric Acid storage tank, transportation system design and design of a conventional jacket heat exchanger to cool nitric acid from (40 0C to 20 0C) were made.