Why is direct steam heating commonly used for pickling solutions? What are its advantages and disadvantages?

Direct steam injection into pickling solutions is a widely used heating method due to its simplicity and ease of implementation, high heating efficiency, and its ability to stir the pickling solution to some extent, which accelerates the pickling process and ensures a more uniform pickling effect. It also blows off hydrogen adhering to the surface of steel tube blanks, reducing the diffusion of hydrogen into the steel substrate. Additionally, it removes impurities adhering to the surface of the steel tube blanks, resulting in a cleaner surface. However, the condensed water in the steam and the moisture produced when the steam encounters the pickling solution can reduce the acid concentration, thereby increasing acid consumption. Direct steam heating can also generate a certain level of noise and vibration, where the former is detrimental to environmental conditions, and the latter is harmful to the pickling tank.