Study on Production of Inhaled Nitric Oxide for Medical Applications by Pulsed Discharge

Nitric oxide (NO) is increasingly being used in the medical treatments of high blood pressure, acute respiratory distress syndrome, and some illnesses related to the lung. A convenient and safe production and operation system of NO is of interest to the medical circle. In this paper, NO was produced using pulsed discharge between needle-plate electrodes made of different materials in dry air under 1 atm.The effects of varying the distance between electrodes, the pulsed discharge repetition frequency, the flow rate of clean air and the reactor operation time on the concentrations of NO and NO₂, and the ratio of NO₂/NO are presented. The method of removing NO₂ is also introduced in detail. The results of the experiment show that on the cure of NO₂/NO versus the distance between electrodes, a minimum ratio of about 7.8% has appeared at the distance of 3.5 mm. The concentrations of NO and NO₂ are increased with increasing the pulsed discharge repetition frequency and decreased with an increase in the air flow rate. The small quantity of toxic NO₂ could be deoxidized through catalytic process to NO which can be used in treatment. The ratio of NO₂/NO decreased to a value below 3% when the gas temperature for deoxidization reached 790 K. Concurrently, the stable concentration of NO could be acquired through a pulsed arc discharge in dry air.