INVESTIGATION ON BIOGAS DISPERSION USING COMPUTATIONAL FLUID DYNAMICS MODELING

Biogas technology is developing rapidly in the recent year due to increment of dependency in human on the renewable energy. Process safety of biogas plant is one of the current issues which is very critical for the process operations. Several cases of fire and explosion related to biofuel plant have alarmed the industries on the potential hazard from current running biogas plant. Limited failure data is available for consequence risk analysis to understand scenario of biogas dispersion. Thus, a study is carried out on the dispersion model of biogas to show the behavior of biogas from pressurized release into the environment by using Computational Fluid Dynamics (CFD) modeling. CFD is a branch of fluid mechanics that uses numerical method and algorithm to solve the problem which involves fluid flow. The code used is CFD-FLUENT by ANSYS Company. CFD dispersion model developed is validated against IP Model Code and PHAST which shows close agreement with deviation at 18% and is acceptable. Gas dispersion study is based on influence of wind speed and the presence of obstacle. Lower wind speed will pose higher risk of fire and explosion due to stable atmospheric turbulence. Presence of obstacle will cause the gas to be easily trapped and create flammable region. Biogas shows shorter hazardous distance as compared to that of methane gas. It can be explained as the lower composition of methane in biogas. Thus, biogas is less flammable than pure methane gas.