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I. Corrosion assessment and evaluation of the head-pulling oil tank: Based on the analysis of the oil sample taken on March 23, 2016, provided by your team (including its properties), the main components are C3-C5, with a hydrogen sulfide content ranging from 400 to 500 mg/kg. First, we need to determine the level of corrosion present in this tank. Based on the \"Compilation of Equipment Management Systems for Refining and Chemical Industries\" issued by the Refining and Chemical Division of China National Petroleum Corporation in November 2011, as well as the definitions provided in the \"Regulations on Safety Inspection of Pressure Vessels\", a comparison was made to determine whether the oil produced at Yumen Refining and Chemical Complex falls under a typical environment of wet hydrogen sulfide corrosion. First, according to the definition of \"Definition and Classification of Wet Hydrogen Sulfide Corrosion Environments\" in the \"Compilation of Equipment Management Systems for Refining and Petrochemical Enterprises\": A medium is considered to be in a wet hydrogen sulfide corrosion environment when there is free water present in the liquid phase, and one of the following conditions is met: (1) The total sulfide content in the liquid water is greater than 50 ppmw ； or (2) in liquid water, the pH is less than 4 and the total sulfide content is greater than or equal to 1 ppmw ； Or (3) in liquid water, the pH is greater than 7.6 and the hydrogen cyanide (HCN) concentration is 20 ppmw or higher, with the total sulfide content being 1 ppmw or higher ； Or (4) the partial pressure of hydrogen sulfide in the gas phase is greater than 0.0003 MPa (0.05 psia). Definition from the Second set of \"Regulations for the Safety Inspection of Pressure Vessels\": (1) Temperature ≤ (60 + 2P), where P is the pressure in MPa (gauge pressure) – corresponding to a dissolved H2S concentration in water of ≥10×10-6 ； (2) H2S partial pressure ≥ 0.00035 Mpa (3) The medium contains liquid water or is at a temperature below the dew point ； (4) pH < 9 or HCN is present. In your test analysis report on the crude oil dated March 23, 2016 (properties), item 3 states: Hydrogen sulfide content: 400–500 mg/kg; it is essentially all hydrogen sulfide, with very little of other forms of hydrogen sulfide present ； Article 4: Since the vapor pressure at room temperature is above 60–80 kPa, it can be concluded that the spherical tanks used for storing stripping oil at Yumen Chemical Plant are in a typical environment of wet hydrogen sulfide corrosion. II. Anti-corrosion solutions: According to the \"Compilation of Equipment Management Systems for Refining and Chemical Enterprises\" issued by the Refining and Chemical Division of China National Petroleum Corporation in November 2011, as well as the \"Regulations on the Management of Boilers, Pressure Vessels, and Pressure Pipelines\", Chapter 3 \"Design, Manufacturing, and Installation\", Article 12 states that for pressure vessels used to store liquefied petroleum gas and high-strength steel pressure vessels (those manufactured from materials with a minimum standard tensile strength of σb ≥ 540 MPa), in the presence of corrosive media that may cause stress corrosion, it is necessary to limit the concentration of such media or take additional anti-corrosion measures. Chapter 1 General Provisions of the \"Guidelines for Corrosion and Protection in Wet Hydrogen Sulfide Environments\": 1.11: While adhering to these guidelines, all refining and chemical enterprises should accelerate the introduction and adoption of new technologies for protecting against corrosion in wet hydrogen sulfide environments, such as various coating and plating techniques. Steel storage tanks, especially spherical tanks made of low-alloy high-strength steel, are most sensitive to hydrogen sulfide, thiol, thioether, sulfur dioxide, and Cl- in the presence of sulfide ions; the following reactions occur: H2S → H+ + HS-. The anodic reaction is: Fe + HS- → FeS + H+ + 2e-, while the cathodic reaction is: 2H+ + 2e- → 2H2 ↓. Had penetrates into the interior of the metal ； Had——Adsorbed hydrogen ； Hab——inhaling hydrogen. Overall reaction: Fe + H2S → FeS↓ + H2↑. The infiltration of 2H into the metal leads to stress corrosion cracking; this phenomenon results from the combined action of anodic dissolution of the metal, which causes cracking, and cathodic hydrogen embrittlement, with the latter playing a dominant role in the destructive process. IV. Electrochemical properties of ZARE compared with Zn, Al, and Al (aluminum-coated) surfaces: In September 2010, experiments were conducted at Dalian University of Technology to compare the performance parameters of ZARE with those of traditional zinc and aluminum coatings. The data showed that the electrochemical properties of the ZARE alloy layer fell between those of zinc and aluminum coatings, being closer to those of the zinc coating; therefore, it provides cathodic protection for steel. Its mechanical properties lie between those of zinc coatings and aluminum coatings, being closer to those of aluminum coatings, with high hardness and impact resistance. VI. Evaluation of anti-corrosion in liquid hydrocarbon spheres for head removal using ZARE technology 6.1 The use of this technology can **reduce the risk of SSCC occurring in the spheres, thereby enhancing the intrinsic safety of the equipment ； 6.2 Corrosion that occurs in spherical tanks is diverse. In terms of addressing the technical issues related to SCCC, ZARE is at the leading level in China. The safety of the spherical tank itself is also dependent on the quality of its heat treatment, as well as whether the levels of S and P meet the required standards. It is also affected by factors such as the presence of defects and inclusions within the tank’s structure. However, by utilizing ZARE technology, its three mechanisms – the \"capture effect\", the \"shielding effect\", and the \"fixed-bed effect\" – provide strong technical support to prevent uniform corrosion and SCCC in spherical tanks. 6.3 If the spherical tank was previously subject to severe corrosion and frequent corrosion incidents, it is recommended to carry out mandatory inspections on an annual basis even after applying the ZARE technology. Check the corrosion condition of the ZARE rare earth alloy layer; if there is wear of the \"sacrificial anode\" in this layer, then the function of the \"sacrificial anode film\" has been fulfilled. This function helps to prevent the penetration of Hab into the metal substrate of the spherical tank, thereby reducing or avoiding the occurrence of hydrogen embrittlement, that is, SSCC. The frequency of analytical tests for substances such as H2O and H2S should be increased, the inspection cycle for spherical tanks shortened, the underlying problems and patterns identified, so that the spherical tanks can be promptly subjected to restorative anti-corrosion treatment using ZARE rare earth alloy coatings. Figure 1 compares the discharge performance of ZARE and aluminum sacrificial anodes in saturated H2S aqueous solutions. The discharge data show that the ZARE rare earth alloy exhibits significantly better discharge performance; its discharge efficiency is 3–5 times higher than that of the aluminum anode.