Characteristics and Maintenance Standards of LNG Storage Tanks

&What are the component characteristics of LNG storage tanks? The inner wall of a low-temperature storage tank is the main component of the tank, which is welded from steel plates that are resistant to low temperatures and have good mechanical properties. Generally, special steels such as A5372 grade, A516Gr.60, Gr18Ni9, ASME 304 are selected. If the bottom plate and ring plate of a certain tank are made of steel plates with a thickness of 16mm and a material of A537CL2, the remaining plates can be made of steel plates with a thickness of 6.35mm and a material of A537CL1. 2 Cold insulation layer The inner side of the cold insulation outer tank lining plate of the tank wall is sprayed with polyurethane foam. Generally, the thermal conductivity of polyurethane foam is required to be ≤ 0.03W/(m · K), the density is 40~60kg/m3, and the thickness is about 150mm. The top insulation of the tank adopts a suspended rock wool insulation layer. For example, a certain tank top is equipped with 4 layers of glass fiber insulation layers, each layer is 100mm thick, with a density of 16kg/m3 and a thermal conductivity of 0.04W/(m · K). Cold insulation at the tank bottom The cold insulation at the tank bottom is relatively complex. In addition to the polyurethane foam sprayed under the steel plate, the waterproof (mainly based on the actual report) structure should be designed. The following figure shows the cold insulation structure at the bottom of a certain tank, including a 65mm thick cushion layer, 60mm thick dense concrete, 2mm thick waterproof (based on actual reports) felt, 2 layers of 100mm thick foam glass, and later covered with 70mm thick concrete to protect the outer tank concrete from the influence of low temperatures. &

Standards for repairing liquid ammonia storage tanks. Generally, users know how important the maintenance work of liquefied natural growth gas storage tanks is. However, if the maintenance is not carried out according to the requirements, it will not have any effect or benefits. Therefore, we hope that everyone can pay more attention to relevant information in their daily lives and make sure to follow the standards for maintenance. What is the standard operation for liquid ammonia storage tanks. The maintenance cycle for storage tanks is generally 60-120 days for medium repairs and 12 months for major repairs. Intermediate repair: Remove running, emitting, dripping, leaking, clean or replace the liquid level gauge, repair or replace the inlet, outlet and drain valves, clear and clean the cooling water coil. Check and repair the Anran valve vent flame arrester. Repair the anti-corrosion layer (based on actual reports) and insulation layer. Major repair: including repairing the internal components of the liquid ammonia storage tank for medium repair projects. For parts found to have cracks, severe corrosion, etc., corresponding repairs or replacement of the cylinder section shall be carried out. Repair can be done using polymer composite materials with attentive service. According to internal and external inspection requirements, as well as after repair or replacement of cylinder joints, leakage testing or hydraulic testing is required. Remove embroidery and keep warm. Handle other issues found during the internal and external inspection of the liquid ammonia storage tank. The repair methods and quality standards for liquid ammonia storage tanks, such as drilling, welding, and replacement of cylinder joints, should be based on the "Capacity Regulations" and other relevant standards, and specific construction plans should be formulated and approved by the technical responsible person of the unit. The materials and valves used for repair should have quality certificates. When using old materials, valves, and fasteners, they can only be used after passing inspection. The fasteners for assembling the storage tank should be coated with lubricating material, and the bolts should be tightened diagonally in sequence. Non metallic gaskets are generally not reusable, and when selecting gaskets, the corrosiveness of the medium should be considered. After repair and passing inspection, anti-corrosion (based on actual reports) and insulation work can be carried out.