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Abstract

In the process industries, hazardous materials can be released accidentally as vapor, gas or liquid and are dispersed in the atmosphere. Ammonia is one of the most extensively used industrial chemicals. It is highly soluble in water and has toxic and corrosive effects caused by its alkalinity. The evaporation of ammonia may cause extreme cooling when spilled on the skin or eyes; cold burns may result. When inhaled, ammonia dissolves in upper airways and small amounts also in the lower respiratory tract; damage to upper airways is therefore more severe. In this paper, simple predictive tool, which is easier than existing approaches, less complicated with fewer computations and suitable for environmental experts, is presented here for the estimation of aqueous ammonia vapor pressure as a function of ammonia molar fraction in aqueous phase and temperature. The proposed predictive tool works for temperatures in the range of 273 to 373 K. The proposed method is superior owing to its accuracy and clear numerical background, wherein the relevant coefficients can be retuned quickly if more data are available in the future. Estimations are found to be in excellent agreement with the reliable data in the literature with average absolute deviation being around 1.74%. The tool developed in this study can be of immense practical value for the engineers and scientists to have a quick check on the vapor pressure of aqueous ammonia solution at various conditions without opting for any experimental measurements. In particular, chemical engineers and environmental scientists would find the approach to be user-friendly with transparent calculations involving no complex expressions.

Introduction

In many industrial installations (storages, pipelines, reactors), hazardous materials can be released accidentally as vapor, gas or liquid and are dispersed in the atmosphere (Labovsk´y, and . Jelemensk´y, 2010) . Ammonia is frequently used in industry, in particular as a cooling agent or in the manufacture of chemical fertilisers. Ammonia is a toxic gas; inhaled at high concentrations and for a long time, it can lead to serious damage (Dandrieux et al, 2001). Breathing levels of 50–100 ppm ammonia in air, can give rise to eye, throat and nose irritation. Ammonia dissolves easily in water ( Busca  and Pistarino 2003). In water, most of the ammonia changes to ammonium, which is not a gas and does not smell. Ammonia and ammonium can change back and forth in water ( Busca  and Pistarino 2003). In wells, rivers, lakes and wet soils, the ammonium form is the most common. People can taste ammonia in water at levels of about 35 ppm. Lower levels than this occur naturally in food and water (Busca  and Pistarino 2003). It, at certain concentrations, is toxic and is therefore considered a pollutant to waters classified for fish and wildlife. It is produced by the decomposition of organisms and by the activity of micro organisms (Prosser, and  Embley, 2002).