Abstract: Supercritical CO2 high pressure extractor is a new type of high-efficiency separation equipment with corrosive medium, high internal pressure and cyclic alternating load, so the working conditions are harsh. To improve this situation, an integral multi-layered structure is adopted for the extractor body, several key points including the material selection of inner cylinder and laminate, the thickness selection of inner cylinder and laminate, the longitudinal and circumferential weld arrangement between inner cylinder and laminate, the gap between inner cylinder and laminate and the gap between laminates are compared and discussed, and the final structural design is determined. The actual operation of equipment indicates that the key points of design are well considered

Key words: multi-layered structure, high pressure extractor, interlayer gap