Abstract: Cold box is one of the most important equipment in ethylene plant. This paper briefly introduces the function and internal structure of cold box in ethylene plant. The main focuses are on the structure design of cold box and the different schemes of top platform. It recommends the material selection for the external pipeline of cod box, the plan layout of the related equipment and its pipe system, the layout of several different types of filter, and the layout of safety valve system. It emphasises the cautions of piping supports for cold pipeline and the design principles of cold support in some particular circumstances.

Key words: cold box, piping design, cold pipeline