Abstract:

This paper designed a water spraying device installed on liquid ammonia tank truck in order to study the diffusion laws of ammonia gas and the suppression influences of water spraying. Firstly, effects of different leakage heights, directions and pressures on ammonia concentration distribution are analyzed using three factors and three levels orthogonal experiments. Results show the most dangerous condition occurs when the leakage height is 44 cm, the leakage direction is upward, and the leakage pressure is 0.3 MPa. Ammonia concentration at the top of operation box reaches 83.12% within 8.5 s. Secondly, effects of different nozzle diameters, atomization angles, spraying pressures and double nozzle intervals on water spraying inhibition are studied by four factors and three levels orthogonal experiments. Results show the importance ordering of 4 facts is: water spraying pressure>nozzle intervals>atomization angle>nozzle diameter. The optimal configuration of the water spraying device is: nozzle diameter 0.3 mm, atomization angle 90̊, water spraying pressure 10 MPa, nozzle interval 26 cm. When the device started to run , the ammonia concentration can be significantly reduced to 2.16% within 1.8 s.  

Key words: fire safety, liquid ammonia tank truck, leakage diffusion, water spraying, orthogonal experiment, emergency disposal