How to do regular inspection of storage tanks
2019-04-03 08:18:09 Click: 204
Storage tanks are the basic equipment for storing and transporting materials in the chemical industry. In order to avoid potential safety hazards in storage tanks, storage tanks must be regularly inspected for safety. Therefore, it is very important for the use unit to understand the inspection safety safety operation regulations of the storage tanks. Today, Sichuan Jindu Yongtong Machinery Factory Xiaobian saw an article about the safety inspection of storage tanks in China's storage tank network. It is necessary to share with you!
First of all, we need to know what is the tank inspection? Tank inspection is divided into external inspection, internal inspection and comprehensive inspection. The cycle inspection of the tank is determined according to the technical conditions of use of the equipment. Generally, the external inspection is carried out at least once a year, the internal inspection is carried out at least once every three years, and the comprehensive inspection is carried out at least once every six years. If the storage tank has a service life of more than 15 years, an internal and external inspection is required every two years. If the service life is 20 years, at least one internal and external inspection is carried out every year.
Secondly, let's take a look at what preparations should be made before the tank inspection.
1. Check the relevant information to understand the defects, problems and treatment methods that occurred during the previous inspection;
2. Remove the material inside the tank and separate it from other equipment and make obvious marks;
3. Replace the residual gas in the tank with the cleaning and treatment, and analyze to meet safety standards;
4. Open all manholes, remove internal parts, and remove dirt from the inner wall;
5. Cut off the power supply of the storage tank. When using the internal inspection of the storage tank, use a low-voltage explosion-proof lamp with a voltage not exceeding 12v or 24v, and there must be special personnel monitoring outside the tank. The voltage of the inspection instruments and tools should not exceed 36v, and good insulation should be used. Cord and reliable ground wire;
6. If the hot work involved, the firework approval procedure must be carried out in accordance with the regulations, and the tank area must be equipped with fire safety, safety and ambulance facilities.
The third point is about the specific operation of the tank inspection. This is also the most important point. It also said that it includes three aspects of non-inspection, internal inspection and comprehensive inspection.
1. External inspection
1) Check whether the anti-corrosion layer, insulation layer and equipment nameplate of the storage tank are intact, whether the safety accessories and control devices are complete, sensitive and reliable;
2) Whether the outer surface has cracks, deformation, local overheating, etc.;
3) Take over the weld seam, whether the pressure component is leaking, whether the fastening bolt is intact, whether the foundation is sinking or tilting, etc.;
2, internal inspection
1) Whether the inner surface and the manhole take over the storage tank with or without corrosive agent wear, whether there is crack in the weld seam, the transition zone of the head or other places where the stress is concentrated;
2) When there is corrosion on the inner and outer surfaces of the tank, multiple wall thickness measurements should be made for the suspected part. If the measured wall thickness is less than the minimum wall thickness of the design, the strength verification should be repeated and a proposal can be made to continue to use and allow the highest working pressure.
3) When there are defects such as decarburization, stress corrosion, intergranular corrosion and fatigue crack on the inner wall of the tank, metallographic examination and surface hardness measurement shall be carried out, and an inspection report shall be submitted.
3, comprehensive inspection
1) No damage inspection of the main weld or shell, the length of the spot check is 20% of the total length of the weld;
2) After passing the internal and external inspection, the water pressure test is carried out according to the pressure of the tank design pressure of 1.25 times and the airtight test is carried out according to the tank design pressure. During the above test, the tank and each part of the weld were free of leakage, and the tank was free from visible abnormal deformation.
Finally, according to the inspection result record, write the inspection report to indicate whether the storage tank can continue to be used. If the storage tank can continue to be used but find the problem, record the processing result and store the inspection report in the tank technical file for later reference.
