1. Site Diagnosis: Analysis of Corrosion Pain Points
As the core equipment of the NGL recovery process, the condenser operates long-term under complex temperature fluctuation and chemical corrosion environments. Its shell and tube sheets typically face the following challenges:
Electrochemical Corrosion: Due to the heat exchange during condensation, a water film easily forms on the equipment surface, accelerating metal oxidation and rust formation.
Stress and Vibration Corrosion: The propane refrigeration or throttling refrigeration process is accompanied by pressure changes and micro-vibrations, causing traditional rigid coatings to crack and peel off easily.
Limitations of Traditional Derusting: The production site is a high-level explosion-proof area. Traditional sandblasting (which easily produces sparks) or pickling (which leaves strong corrosive residues) is often difficult to implement and poses a high risk of physical damage to precision equipment.
2. Core Technology Application
In response to the above operating conditions, this project adopted a composite solution of "Non-Acid Rust Conversion Technology + High-Performance Functional Anti-corrosion Topcoat":
Non-Acid Rust Conversion Technology (Base Layer): Typical corrosion products are Fe₂O₃, FeOOH, and a certain amount of Fe₃O₄. After film formation, under the action of nanomaterials, FeOOH transforms into α-FeOOH and β-FeOOH with more stable crystal forms. The nanomaterials also continuously capture escaped, residual, or newly formed rust molecules (Fe₂O₃), converting them into stable FeO·Fe₂O₃ (i.e., Fe₃O₄) and O₂ through nano-exchange separation, significantly extending the protection period.
High-Performance Composite Topcoat (Surface Layer): An anti-corrosion topcoat with excellent temperature change resistance and resistance to chemical media penetration is selected to provide a long-term physical barrier for the condenser, resisting attack from acidic gases and industrial atmosphere.
3. Construction Process
The construction follows the principle of "Fine Treatment, Efficient Conversion, Strengthened Protection":
Surface Pretreatment: Use steel brushes or power tools to remove loose floating rust, welding slag, and oil. Retain the firm rust layer (approx. 50µm - 10µm) remaining after manual derusting.
Rust Conversion Treatment: Spray or brush apply the non-acid rust converter. Ensure even coverage and observe the rust color gradually changing from reddish-brown to a dark black passivation layer.
Drying Inspection: After the conversion layer has fully reacted and dried, check the continuity of the film to ensure no missed spots or bubbles.
Topcoat Application: Apply the high-performance anti-corrosion topcoat in two separate coats. The first coat enhances adhesion, and the second coat achieves the design thickness, improving overall weather resistance.
4. Customer Value
Through this repair, the following core values were achieved for the customer:
Ensuring Dew Point Control Accuracy: The heat exchange efficiency of the repaired condenser is restored and stabilized, ensuring precise condensation of components like ethane and propane in the natural gas, preventing the risk of "liquid hammer" during pipeline transportation.
Enhancing Resource Recovery Profitability: Extends the service life of critical equipment, reduces unplanned downtime, and ensures efficient recovery of high-value LPG and NGL.
Construction Safety and Environmental Protection: The use of non-acid technology avoids acid mist pollution and sandblasting dust, complying with increasingly stringent environmental protection and explosion-proof operational requirements in oil and gas stations.
Reducing Lifecycle Cost: Compared to traditional solutions, the construction period is shortened by approximately 30%, and the extended lifespan significantly reduces future maintenance frequency.
