Desulphurisation at an Alumina Plant Using Bauxite Residual Slurry

摘要

A few years ago EurAllumina, a leading alumina producer based in Portoscuso (Sardinia, Italy) faced a dilemma common to several other industrial Plants: in order to comply with the regulations governing emission limits, EurAllumina had either to burn low-sulphur fuel oil in their boilers and furnaces or to install desulphurization Plant and continue to burn the cheaper high-sulphur fuel oil. EurAllumina adopted this second choice, being this also an environment-friendly solution in terms of residue (red mud) basin management. The Plant is fitted with three oil-fired boilers, each one with 170 t/h steam capacity, and three alumina calcining kilns (two rotaries up to 1,050 t/d and one static up to 1,650 t/d); two DeSo{sub}x systems have been installed, one to control So{sub}x emissions from the boilers and another dedicated to So{sub}x emissions from the three alumina calcining kilns. The two DeSo{sub} units have been successfully commissioned this year by Hamon-Research-Cottrell Italia. The technology called BRDS -Bauxite Residue Desulphurization System - developed and realised for the DeSo{sub}x system, is one of the licensable processes of Sumitomo Chemical Co., Ltd. (SUMITOMO BRDS PROCESS). Based on the SUMITOMO BRDS PROCESS, Hamon Research-Cottrell Italia, with EurAllumina co-operation, introduced an unconventional approach in some critical process areas, such as the dilution of mud with recovered liquid from the absorbing tower, the absorber, the hood and demister washing sequence, the chimney tray realisation, the equipment and material selection.