Effect of Pretreatment on Enamel Properties of Packed and Enameled Heat Exchangers for Gas-Gas Heaters

摘要

Pickling and nickel dip are no longer allowed in the pre-treatment for packed and enameled heat exchangers because of environmental regulations. Without pickling and nickel dip pretreatment, the adherence of the enamel becomes worse. After the introduction of a quantitative method to determine the surface cleanliness, the effect of time, temperature and concentration on the surface cleanliness and enamel adherence were studied on a system using electrostatic wet spray onto enameling grade low carbon steel.