Surface treatment methods and process design for LNG storage tanks

Firstly, the surface treatment method for carbon dioxide storage tanks generally requires surface treatment, but there are more than one surface treatment techniques, each with its own advantages. If you are not clear about the specific situation before, you can take a look at the detailed introduction shared by the carbon dioxide storage tank manufacturer, and then you can have a better understanding. There are three surface treatment technologies for LNG storage tanks: ① Surface whitening treatment; ② Surface mirror gloss treatment; ③ Surface coloring treatment. 1、 Surface natural whitening treatment: During the processing of stainless steel, black oxide skin is produced through rolling, edge tying, welding, or artificial surface heating treatment. This hard gray black oxide skin is mainly composed of NiCr2O4 and NiF EO4 components, which were previously removed by strong corrosion methods using hydrofluoric acid and nitric acid. But this method has high costs, pollutes the environment, is not beneficial to human health, and is highly corrosive, gradually being phased out. There are currently two main methods for treating oxide scale: ⑴ Sandblasting (shot) method: mainly using the method of spraying micro glass beads to remove the black oxide scale on the surface. ⑵ Chemical method: Use a pickling passivation paste and a cleaning solution with inorganic additives at room temperature for immersion washing. Thus achieving the whitening treatment of the natural color of stainless steel. After processing, it basically looks like a dull color. This method is more suitable for large and complex products. 2、 Surface mirror gloss treatment methods: Depending on the complexity of stainless steel products and user requirements, mechanical polishing, chemical polishing, electrochemical polishing, and other methods can be used to achieve mirror gloss. 3、 Surface coloring treatment: Stainless steel coloring not only endows stainless steel products with various colors, increases product variety, but also improves product performance and corrosion resistance (based on actual reports). There are several methods for coloring stainless steel, including: (1) Chemical oxidation coloring method: It is the color of a film formed by chemical oxidation in a specific solution, including dichromate method, mixed sodium salt method, sulfurization method, acidic oxidation method, and alkaline oxidation method. INCO is commonly used, but to ensure consistent color of a batch of products, a reference electrode is used for control. ⑵ Electrochemical coloring method: It is the color of a film formed by electrochemical oxidation in a specific solution. ⑶ Ion deposition oxide coloring method chemical method: It is to place stainless steel workpieces in a vacuum coating machine for vacuum evaporation coating. For example, watch cases and straps coated with titanium gold are usually golden in color. This method is suitable for processing large quantities of products. Due to the large investment and high cost, it is not cost-effective to produce small quantities of products. ⑷ High temperature oxidation coloring method: It is a process of immersing the workpiece in a specific molten salt to maintain a certain process parameter, forming a certain thickness of oxide film on the workpiece, and presenting various colors. Gas phase cracking coloring method: relatively complex and less commonly used in industry. The choice of stainless steel surface treatment method should be based on the product structure, material, and different surface requirements, and the appropriate method should be selected for treatment. Secondly, the process design of LNG gasification stations involves the operation of certain corresponding equipment when designing natural growth gas storage tanks to maintain the overall structural stability. The following analysis is mainly based on the actual situation. 1. The design of LNG storage tanks (1) Determination of LNG storage tank form Currently, the form of LNG storage tanks is closely related to their storage capacity and also inseparable from the storage space. When selecting low-temperature storage tanks, most of the liquefied natural growth gas low-temperature storage tanks in China do not have significant advantages. When selecting tank drainage, low-temperature equipment should be used as much as possible. In addition, comprehensive consideration should be given to storage temperature and operating efficiency. (2) The determination of design pressure and calculation pressure is based on the analysis of the pressure that the storage tank can withstand. The pressure of the storage tank should not exceed 0.8 MPa, otherwise it will easily cause temperature changes. At the same time, the structure of the storage tank is determined by the magnitude of the pressure it can withstand, and analysis needs to be conducted on the basis of isolating the air pressure. The application of the storage tank should isolate the surrounding heat sources and pressure. 2. When designing a turbocharger, the pressure on the storage tank should be taken into account. When carrying out low-temperature treatment, the pressurization system of the low-temperature container should be combined to protect the use of a constant temperature gasifier under constant temperature conditions. A pressurized design should be adopted to carry out corresponding treatment work. If under natural environmental conditions, the design of the gasifier needs to take into account changes in the climate environment and the operation treatment of natural growth gas temperature, and carry out a pressurized design. If the temperature of the vaporizer remains constant, it should be controlled in conjunction with high-pressure temperature design to reduce the impact of climate conditions and provide important protection for the operation of the water bath type booster. 3. The design of pressure regulation, metering, and odorizing devices is analyzed in conjunction with LNG gas supply stations. Reasonable equipment for regulating pressure changes is adopted to control the command pressure. Based on automated regulation, simple air pressure is provided for corresponding construction operations through metering operations and the use of odorants, facilitating the discharge of odorous gases into natural gas pipelines.