Under the strict management of design, manufacture, inspection and use of large-scale pressure vessels currently in use, few serious defects have been found. Shortening the inspection time as much as possible is the concern of the majority of pressure vessel users. Acoustic emission technology meets the above requirements. Because of its simplicity, economy, and high sensitivity, it can detect "dynamic" defects and evaluate the hazard level of the type of defects, which can greatly shorten the inspection time and reduce the downtime. It reduces the losses caused by blind repair and scrapping of pressure vessels, and at the same time avoids the cost of auxiliary work such as can opening and grinding. It has developed into one of the main non-destructive testing methods for pressure vessel inspection and safety assessment. There is a huge application market for periodic inspection of pressure vessels. The promotion and application in Guangxi will bring huge economic benefits to users. Principles of acoustic emission technology. The phenomenon of rapid release of energy from local sources in materials to generate transient elastic waves is called acoustic emission. Acoustic emission technology is to monitor cracks through the acoustic emission sensor group on the outer surface of the equipment when the equipment is pressurized in service, such as a hydraulic test. Expansion, rupture and other defects release acoustic energy emitted by the acoustic emission wave, so as to monitor the technology of these defects. The advantages of acoustic emission technology. Compared with other non-destructive testing methods such as ray, ultrasonic, etc., acoustic emission technology has the following advantages in the detection of large pressure vessels: because it provides dynamic information of defects under stress, it is suitable for evaluating the actual damage degree of defects to the structure; realizes continuous online Monitoring, suitable for on-line monitoring of industrial processes and early or imminent damage prediction; due to the low requirements for the proximity of the inspected components, it can adapt to complex detection environments, such as high and low temperature, nuclear radiation, flammable, explosive and toxic environments; Since it is not sensitive to the geometry of the component, it is suitable for components with complex shapes that are limited by other detection methods; the use of multiple channels to achieve rapid detection of the whole or a large range, and a small amount of removal of the insulation layer, after a single loading or test process, it can be Determining the location of the defect, the detection efficiency is high, which can greatly save time and money, and some can also avoid the process of opening cans, and the economic benefits are very obvious.