Ammonia dispersion at an industrial site

Ammonia is used as refrigerant for the cooling of industrial processes. Cooling with ammonia is applied as it is an environmentally friendly refrigerant and enables energy efficient cooling. Ammonia is however also a toxic refrigerant and it is flammable. This leads to specific safety requests.

A pharmaceutical company in Flanders is planning the construction of a new refrigeration building on its campus. The building will be equipped with sensors to monitor for leaks in the ammonia cooling system and air scrubbers can be turned on to remove ammonia from the air exhaust of the building. The cooling building will be constructed close to office buildings. VITO has studied the dispersion of ammonia form the air exhaust to the surrounding campus.

This study applied 3D computational fluid dynamics (CFD) simulations of the dispersion from the air exhaust to calculate ammonia concentration levels on the campus. The simulations have been conducted for a variety of meteorological conditions. The results have been analyzed to obtain the ammonia concentrations at the air intake of all surrounding buildings. The critical values of the ammonia concentrations and flow rates from the cooling building are the values when the odor limit in an office building will be exceeded. These critical values are derived as a function of the wind speed and wind direction.

The results are applied to evaluate the safety measures and ensure a safe work environment for all staff, under all atmospheric circumstances even if an ammonia leak would occur.

Ammonia dispersion for a variety of wind directions.