Petrochemical liquefied balloon tanks are prone to stress corrosion due to the influence of low-temperature wet hydrogen sulfide. How to prevent corrosion more reasonably?

In view of the problem that liquefied balloon tanks are prone to stress corrosion due to the influence of low-temperature wet hydrogen sulfide, the following anti-corrosion methods can generally be adopted: 1. Choose materials that are resistant to hydrogen sulfide corrosion: In the process of manufacturing spherical tanks, you can choose steel materials that are resistant to hydrogen sulfide corrosion. This type of steel can resist the corrosion of low-temperature wet hydrogen sulfide. 2. Use anti-corrosion coatings: Coating the inner wall of the spherical tank with an anti-corrosion coating that resists hydrogen sulfide corrosion can effectively resist hydrogen sulfide corrosion. 3. Environmental control: In the storage environment, the corrosive properties of hydrogen sulfide are reduced by controlling conditions such as temperature and humidity. 4. Improve welding quality: Since the weld bead is an important part of corrosion, the welding quality needs to be strictly controlled during the welding process to prevent excessive stress on the weld, resulting in cracks. 5. Regular maintenance and inspection: Regularly perform maintenance and inspection on the inner wall of the spherical tank to detect corrosion in time, prevent corrosion from expanding, and reduce safety hazards. 6. Cathodic protection: By means of electric current, the inner wall of the spherical tank is in an electrochemical cathodic state, thereby inhibiting the occurrence of corrosion. .

(1) Use highly corrosion-resistant materials. A Reduce inclusions in steel and reduce sulfur and phosphorus content ； B The oxygen content should be limited, and the oxygen content should be less than 0. 002% ； C The carbon content in the steel must be reduced as much as possible while meeting the mechanical properties and thickness of the steel plate. ; (2) Stress relief treatment A. When forming the spherical shell plate, it is necessary to control the quality of manufacturing and installation, especially the quality of welding, to avoid hot cracks and cold cracks during the welding of the spherical shell plate. It is necessary to strictly control the preheating, postheating and interlayer temperature during welding. B The energy of the welding line will greatly affect the toughness of the welding metal and the heat shadow l-direction zone. If the energy of the welding line is too large, the elements of the alloy will be burned and the impact energy of the welded joint will be reduced. ； If the energy of the welding line is too small, it will cause defects such as Zhu fusion, incomplete penetration and slag inclusion. Therefore, the energy of the welding line must be strictly measured and controlled. C. It is necessary to strictly control the installation process and arrange the installation sequence reasonably. Correct welding T configuration and welding sequence should help reduce residual stress and welding distortion. Welding should be symmetrical and the welding speed should be as consistent as possible ； In principle D: The welding sequence is longitudinal welding first and then circumferential welding. After the external welding is completed,: Welding eliminates the interior. When welding, the welding joint must be cleaned and kept clean. C: Reduce residual stress to significantly prevent stress corrosion cracking; overall heat treatment (3) Corrosive severity control of corrosive environment The content of ammonia sulfide in liquefied petroleum gas must be strictly controlled.