A THEORETICAL-STUDY OF ABSORPTION OF TOXIC GASES BY SPRAYING

The feasibility of controlling toxic gases by absorption using liquid sprays has been examined previously. In this paper the physical and chemical phenomena taking place in a gas-spray environment are described in more detail, and a mathematical model of the interactions is developed. The model was implemented in the PSI-Cell computer code and numerical solutions were obtained for a number of different configurations and spray patterns (i.e. vertical and horizontal co-current and counter-current flow, upwards and downwards cross-flow). The effects of several spray parameters (e.g. flow rate, location and drop-size distribution) and gas parameters (e.g. solubility, chemical reaction rate) were considered. Several simulations of water spraying of specific gases (HF, NH3, SO2 and H2S) were carried out. The effectiveness of gas removal estimated by the numerical model was found to compare favourably with HF laboratory tests. Favourable agreement was also shown with qualitative field data on NH3 and SO2 spraying. Absorption using water spraying provided an effective means of control for highly water soluble gases with fast ionization reactions in the liquid phase (e.g. HF, NH3), but it did not result in substantial gas removal when the gases were only moderately water soluble (e.g. SO2). © 1990.