Scrubbing of Flue Gases with Sea-Water

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PAPER NO. 34 SCRUBBING OF FLUE GASES WITH SEA-WATER INTRODUCTION M. Radojevic, Derartment of Fuel and Energy, Umversity of Leeds, Leeds I.S2 9JT, UK Two major environmental problems of the present day, acid rain and global warming, are caused by emissions of gaseous pollutants from a variety of industrial sources, the most significant being fossil fuel combustion plants. The abatement of these problems is high on the political agendas of industrialised countries and international organisations. In view of these initiatives there is currently a growing demand for practical and economical air pollution control technologies which could be applied to a wide range of industrial plants. Industrial sources and environmental consequences of major pollutant gases are summarised in Table 1. Values of Henry's Law constant are also given as an indication of the aqueous solubility of the respective gases. One of the earliest methods of air pollution control, at Battersea power station , London in the 1930's relied on the high aqueous solubility of sulphur dioxide to effectively desulphiirise flue gases (1). After passing through a cyclone in order to remove dust particles the flue gas was scrubbed with Thames river water containing finely ground chalk. The process removed about 90% of the sulphur dioxide in the flue. The liquid effluent was aerated and then diluted with cooling water from the power station condensers before being returned to the river. Since then a variety of desulphurisation techniques have been developed and applied to industrial plants, including a number of methods which involve the scrubbing of flue gases with sea-water (2). Table 1. Sources, consequences and values of HenlY's Law constant eH) for some flue eases FFC = fossil fuel combustion CI = chemical industry Gas S02 C02 NOx HCI Major industrial sources FFC, CI FFC FFC, CI CI FFC, CI Environmental H (mol 1-1 atm-1) consequences Acid rain 1.4 Global warming 3.4 x 10-2 Acid rain, NO : 1.9 x 10-3 photochemicalsDlog N02: 7.0 x 10-3 Acid rain 0.1 Acid rain 20 1