STUDY OF ACCIDENTAL RELEASES HEAVY GAS DISPERSION COMPARING SLAB MODELS AND SCREEN-3 MODEL

Most of the chemical industries such as petroleum industries, refinery industries, fertilizer industries etc. releases rarely accidental gases it may be heavy gases like liquefied petroleum gas, chlorine, natural gas, ammonia etc do occur. The impact of these heavy gases (high molecular weight than air) in the surrounding atmosphere is very harmful/ hazardous to the human health because the formation of heavy clouds of the respective gases nears the earth surface. In present paper, considered the effect of atmospheric parameter such as, direction of air, wind speed etc. as well as stack parameter like height of stack and released gas parameter as density, venting speed of the gas on the dispersion of heavy gas in to the surrounding. Here present work done to identify the downwind concentration along with the horizontal distances through a case study of industrial accidental release (Ammonia Gas) scenario. SLAB model for the heavy gas dispersion and SCREEN-3 a single source Gaussian plume model these two types of dispersion models readily available in the public domain for industrial releases of gases. Result of downwind concentration of ammonia vapour in both of model has presented.