Management and inspection of atmospheric storage tanks

The management mode based on the storage tank accident, namely the mode of accident handling and emergency repair, is essentially an extensive management mode of "let it go". Once a major accident occurs, the consequences are immeasurable. The management mode of periodic maintenance is to inspect and maintain storage tanks according to a certain period. This mode will cause inconvenience to production, and does not consider the individual differences of storage tanks. There are excessive inspection and maintenance and insufficient inspection and maintenance, resulting in economic losses or Security risks. The risk-based management model is a new management model that has emerged in recent years. This management model uses the risk-based inspection (RBI) technology to perform risk assessment on a single storage tank or a group of storage tanks to determine the risk of each storage tank. Based on the risk situation, the inspection time and inspection strategy of each storage tank are formulated to realize the safety management of storage tanks.

Testing method

The in-service inspection of atmospheric storage tanks includes three forms: routine inspection, annual inspection and periodic inspection.

Routine inspection is a visual-based, close-up inspection of the external condition of the storage tank, including whether the storage tank has leakage, deformation of the tank wall, signs of settlement, and the operation of the insulation device, safety accessories and related accessories of the tank body condition, etc. The annual inspection is an online inspection to ensure the safety of the storage tank during the periodic inspection period. The annual inspection is mainly based on external macro inspection. In addition to the content of the routine inspection, it should also include the thickness measurement of the wall and roof, and foundation settlement. Detection and lightning protection and anti-static grounding resistance detection, etc. Periodic inspection is to carry out a more comprehensive inspection of the storage tank according to a certain inspection cycle, and the periodic inspection can adopt the online inspection method or the open tank inspection method according to the actual situation.

Periodic inspection mainly includes:

(1) Settlement detection of tank foundation;

(2) Inspection of safety accessories;

(3) Inspection of the tank.

The inspection of the tank includes not only the inspection and testing of the tank bottom plate, tank wall plate and tank top plate, but also the inspection of the anti-corrosion coating and thermal insulation inside and outside the tank.

The traditional inspection methods mainly include:

(1) Macro inspection;

(2) Ultrasonic thickness measurement;

(3) Surface defect detection (magnetic particle/penetration);

(4) Buried defect detection (ultrasonic/ray);

(5) Magnetic flux leakage detection of tank bottom;

(6) Vacuum leak test.

The emerging inspection methods mainly include:

(1) On-line detection of acoustic emission;

(2) Guided wave detection;

(3) Robot online detection technology;

(4) Wall-climbing ultrasonic continuous thickness measurement technology.