Comparison Study on the Corrosion Resistance of Stainless Steel and Copper Tubes in LiBr Solution in Heat Pump

Abstract

Cooling water surplus heat utilization by lithium bromide absorption heat pump is a significant measure of energy saving in thermal power plants, however, lithium bromide corrosion on tubes seriously affects the reliability of heat pump absorbers. Through weight loss methods and electrochemical polarization methods, corrosion resistance of copper tube and five types of stainless steel tubes 304,316 L,436L,444 and 445J2 have been studied under absorber conditions. The results reveal that the corrosion resistance of five types of stainless steel tubes is significantly better than copper tubes in 62wt-% LiBr solution, and the corrosion resistance of the order of tubes is 316L>445J2≈444>304≈436L>>TP2. Inhibition effect of lithium molybdate is a little better than sodium molybdate at the same weight concentration.