OPTIMIZATION OF CLEANING EVAPORATOR TUBES IN BAYER PROCESS

During Bayer process of Jajarm Alumina Complex, sodium aluminosilicate scales in different equipment, especially in thermal heat exchangers of condensation units of sodium aluminates. This leads to reducing total heat transfer coefficient and increasing energy consumption. We use sulfuric acid as a solvent, acetic acid as an organic additive and refalgan as a corrosion inhibitor. Using 3 %w of acid with 0.1 %w of refalgan in 25 oC and 75 minutes removed the whole scales from inner surface of heat exchanger tubes. Using optimum amounts in industrial scale, causes to %80 increase of heat transfer coefficient and tubes corrosion are measured 0.00037 mm. The effect of organic additive acetic acid on descaling was assessed separately, which led to %15 increases in the descaling efficiency.

Keywords:

Bayer process , sulfuric acid , descaling , heat exchanger , aluminosilicate