Ammonia large scale atmospheric dispersion experiments in industrial configurations

Abstract

A programme of large-scale experiments for atmospheric dispersion was carried out by INERIS over a period extending from December 1996 to April 1997. The objectives of the test campaign were to measure anhydrous ammonia concentrations in a range of few meters to 2 km from the release, in order to generate data to be used to improve 2-phase release modelling.The discharges were released from a 6-tonne storage tank of pressurised liquid ammonia and through a discharge device with an outlet diameter of 2 inches. Fifteen trials were carried out with various release configurations corresponding to industrial situations (impinging jets on the ground and on a wall at various distances, release through a flange without seal...). The quantity of ammonia discharged from the liquid phase varied according to the tests, from 1.4 ton to 3.5 tons for durations between 7 and 14 minutes and, therefore, at flow rates between 2 and 4.5 kg/s. Approximately 200 sensors were settled downwind to measure ammonia concentrations and temperature in the plume. These tests showed that for discharges with identical flow rates the distances corresponding to the same concentration vary a lot according to the configurations. These distances tend to be reduced by the presence of obstacles or bounds that collected liquid ammonia. In the paper, the main experimental results are presented in order to enable the comparisons with numerical predictions.

Mitigation of Ammonia Dispersion with Mesh Barrier under Various Atmospheric Stability Conditions

“…Fig. 3 compares the numerical result of the present study and the experimental data of Bouet et al (2005). The experi mental data are obtained from a groundlevel line source of ammonia leak.…”

“…The main size of model is obtained from Bouet et al (2005). The computation al domain selected for the present simulation is a sur face 100 mlong and 30 mhigh along the center of the leakage, and employs two dimensional in order to reduce computational expense.…”

“…To validate the numerical accuracy and obtain a better understanding of fundamental windbuoyancydriven flow, the threedimensional computational domain used in this study is kept identical with the experimental model proposed by Bouet et al (2005), which consists of 3 cases with the different atmospheric conditions and leak rates. The height H of the barrier is 3 m. In addi tion, the distance of the barrier to leak position is 1 m and 3 m for the second and third tests.…”

“…The height of the computational domain is kept at 4H. Three experimen tal tests of Bouet et al (2005) are chosen with/without solid barrier arrangement to compare the dispersion of the ammonia in downstream of leakage (Table 1). Fig.…”

Analysis on Dispersion and Toxic Effect of Liquefied Ammonia Tank Release Based on PHAST

“…Therefore, studies on liquefied ammonia dispersion and toxic effect have multiple significance meanings like dividing security zone and preventing fire and explosion accidents. A number of domestic and foreign researchers have studied the dispersion of ammonia [1][2][3] and consequence simulation [4][5][6]. Some companies have developed calculation softwares, such as SAVE II, SIGEM, WHAZAN, EFFECTS, PHAST, RISKCURVES, SAVEMODE, STAR [7].…”