LNG full containment tankHow is the tank bottom produced and installed? How is regular inspection conducted? What is the welding process like?

The production and installation of the LNG full containment tank bottom should proceed as follows:

1. Before laying the bottom plate of the LNG full containment tank, a cross centerline should be drawn on the foundation. The middle plate should be laid first according to the layout diagram, followed by the middle plates and side plates on both sides. During laying, it should be aligned and temporarily fixed with clamps or spot welding. The allowable deviation for the overlap width of the bottom plate is 5mm;

2. The type and size of the butt joints between the middle plates of the LNG full containment tank bottom and between the middle plates and edge plates should meet the requirements of the design drawings and transition from the overlapping parts.

LNG full containment tankThe inspection of LNG full containment tanks by the manufacturer is divided into external inspection and internal regular inspection. The inspection cycle for LNG full containment tanks should be determined based on the usage standards of the tanks.

1. Internal Inspection

1. Check whether the inner surface layer and the junction with the manhole of the tank are damaged by corrosive agents, and whether there are cracks in the welding or stainless steel head connection areas or other stressed areas;

2. When there is corrosion on the inner and outer surfaces of the tank, several wall thickness measurements should be taken at suspicious locations. If the measured thickness is lower than the minimum wall thickness specified in the design, the compressive strength should be re-verified, and it should be clearly stated whether high pressure can be reapplied and the recommendations allowed;

3. If there are defects such as decarburization, stress corrosion, stress corrosion, fatigue cracks, etc., in the inner cavity of the tank, metallographic inspection and surface strength measurement should be conducted, and a testing report should be clearly provided.

2. External Inspection

1. Check whether the anti-corrosion layer, insulation layer, and equipment identification plates of the tank are intact, and whether the operating equipment is complete, agile, and reliable;

2. Check for cracks, deformation, local overheating, etc., on the outer surface;

3. Check for leaks in the welded and stressed components, whether the tightened anchor bolts are intact, and whether there are any abnormal phenomena such as subsidence or tilting. At the butt joint, the bending should be heated with an acetylene flame, and the offset should not exceed 1mm;

3. The welding sequence of the LNG full containment tank bottom plate is very important. Welders are required to strictly follow the following process:

1. For the welding of the middle plate, short seams should be welded first, followed by long seams; before welding the short seams, the temporary weld points between the strips and the side strips or side plates should be ground off; during the welding of the long seams, the welders should distribute evenly and symmetrically, welding from the center outward, using a step-back method;

2. The lap joints at the edges of the bottom plate should be converted into butt joints, welded symmetrically at intervals, and evenly reserved for shrinkage. The butt gaps should be filled and welded flat, and the surface of the weld should be smooth and even;

3. To reduce welding deformation, the annular fillet welds between the bottom plate and the bottom ring plate should be distributed symmetrically inside and outside, and can be welded in the same direction in segments, or the welding sequence can be to weld the inner ring first and then the outer ring.LNG full containment tankWe are the manufacturer of LNG full containment tanks, and for more related content, you can contact us. We can introduce from different aspects.

We are a manufacturer of LNG full containment tanks. For more related information, please contact us. We can introduce it to everyone from different aspects.