Gas Dispersion Modeling

Involvement of flammable or toxic materials in a process plant causes the risk of
accidents. Hazard analysis and risk-based management are important to prevent
escalation of dangerous event. Due to ill-defined leakage conditions, there are a few
areas of uncertainty which lead to difficulty in positioning gas detectors. In industry,
positioning of gas detectors has always been based on personal expertise rather than
computer modeling. This method lacks of consistency and it tends to focus on
locations of potential leakage but not locations of total gas accumulation.
Development of gas dispersion modeling tool aids in better understanding of possible
path of gas distribution and accumulation. Based on the dispersion results, possible
locations of gas detector can be indicated. Gaussian plume model is being employed
in this project to study dispersion of natural gas. Natural gas is a type of light gas and
neutrally buoyant. Effects of meteorological parameters and gas emission rate are
factors affecting dispersion pattern. After filtering the concentrations fall out of
flammable range, locations where concentrations within flammable range occur are
identified using top view plot and front view plot. Consequently, locations of gas
detector can be determined.