Abstract
Aim: The article shows the influence of used spraying equipment (nozzles) on the ammonia absorption process.
Introduction: Ammonia, due to its properties and degree of use, poses a serious threat to life and health in the event of industrial accidents. Research carried out in Poland and abroad indicates that absorption (the process of exchange of mass) is an effective way to neutralize this substance.
Methodology: In order to reach the aim it was necessary to carry out tests to determine the rate of change of the concentration of ammonia in a closed area during operation of the nozzle. The tests were performed at a test stand. The main element of the stand was a test chamber made of transparent plastic with a side length of 1200 mm. The nozzle was located in this chamber. The study started when concentrations of NH3 inside the chamber were stabilized. During the leak of liquid from the atomizer, the level of ammonia was measured using a photoionization detector (PID). The apparent speed of absorption (kp) and the half time of the reduction on concentration (t1/2) in kinetic areas with maximum absorbency were determined for the selected liquid parameters and the degree of fragmentation of the drops of water on the basis of the obtained results. Three types of nozzles were used in the tests: spiral, mist and full cone spray.
Results: Studies indicate that the liquid flow parameters (pressure and efficiency) and the average surface diameter of water drops in a distributed flow are dependent on the type of device used in the injection. At a constant value of water efficiency (V = 130 dm3/h), the degree of water droplets fragmentation differed depending on the type of nozzle. The average droplet surface diameters varied from 185 mm do 600 mm. A significant influence of the size of water droplets on the rate of absorption of ammonia has been indicated. Studies show a linear relationship between apparent speed of absorption, time of half reduction of the ammonia concentration in kinetic area with maximum absorbency and the diameter of the drop Ds. In case of full nozzle cone misting, it was discovered that with increasing pressure (in the range of 2-8 bar) and water efficiency (100 dm3/h to 180 dm3/h) the value of t1/2 decreases and kp increases at almost constant value of Ds.
Conclusions: Absorption is a common method of risk neutralization associated with an uncontrolled release of ammonia as a result of industrial accidents. The efficiency of the process depends on the characteristics of the created diffuse water stream. The type of spraying nozzles affects this diffused water stream.
Keywords: absorption, ammonia, leak, nozzle, fragmentation of water drops
Type of article: original scientific article