As one of the core pieces of equipment in the petrochemical industry, heat exchangers play a crucial role in heat transfer throughout refinery processes. Heat exchangers in refinery can function not only as heaters or coolers on their own, but also as essential components in the production of many chemical products. From an energy efficiency perspective, heat exchangers in petroleum refineries recover and reuse waste heat generated during processes, significantly improving overall energy utilization. They are therefore regarded as key equipment for energy saving and emission reduction in modern refineries.
Analysis of the Main Causes of Heat Exchangers in Oil Refinery
In refinery and petrochemical units, heat exchangers operate continuously under complex flue gas conditions characterized by high temperature, high humidity, and the presence of sulfur- and acid-containing components. As a result, corrosion is almost inevitable in such environments. Rather than being caused by a single factor, corrosion typically results from the combined effects of multiple physical and chemical mechanisms, which can be summarized into the following three main categories.
1. Low temperature corrosion caused by sulfuric acid vapor condensation
In refinery furnace or process flue gas systems, the flue gas typically contains a certain amount of sulfur oxides (SO₂ and SO₃). In the presence of water vapor, these components can further react to form sulfuric acid vapor.
During heat exchange, as the flue gas temperature decreases, if the temperature of the cold-end heat-transfer surface in the refinery heat exchanger falls below the sulfuric acid dew point, gaseous sulfuric acid will condense and form a liquid acid film on the metal surface.
This acid film continuously reacts with the metal material, leading to typical low-temperature sulfuric acid corrosion (acid dew point corrosion).
Its characteristics are as follows:
- It most commonly occurs in the cold-end region of heat exchangers
- Corrosion tends to be localized or develop in a patchy, uneven pattern
- The severity gradually increases over operating time
- It is often accompanied by wall thinning and may eventually lead to perforation risks
Therefore, this type of corrosion is one of the most common failure mechanisms in flue gas heat exchange equipment used in oil refineries.
2. Chemical corrosion of sulfur-containing gases and acidic components
In addition to sulfuric acid vapor, sulfides and other acidic gases such as H₂S and SO₂ are commonly present in flue gas. These gases will cause sustained chemical corrosion of metal materials under high-temperature or condensation conditions.
Especially when the metal wall temperature of the heat exchanger in a refinery is below the acid dew point, sulfur dioxide in the flue gas will combine with water vapor to form trace amounts of acidic condensate on the wall. These acidic liquids will continuously dissolve and damage the protective layer on the metal surface, thereby accelerating the corrosion process.
This process usually manifests as:
- Coexistence of uniform corrosion and localized pitting corrosion
- The metal surface gradually loses its smoothness
- After the failure of the corrosion-resistant layer, the corrosion rate significantly accelerates
Under long-term operating conditions, this chemical corrosion will significantly reduce the structural integrity and service life of heat exchanger in petroleum refinery.
3. Synergistic effect of smoke particle erosion and corrosion
In addition to gaseous corrosive media, refinery flue gas often contains a certain amount of solid particles, such as dust, catalyst residues, or small particles generated by combustion.
When the flue gas flows at high speed through the surface of the heat exchanger, these particles will have a continuous impact and wear effect on the areas that have already undergone slight corrosion. Especially in acidic environments where the strength of the metal surface has been weakened, particle erosion will further amplify the destructive effect.
Corrosion-Resistant Materials and Glass Plate Heat Exchanger Solution
In the refinery and petrochemical industries, traditional metal heat exchangers have long faced a critical issue: they are prone to corrosion in environments containing sulfur, acidic components, and low-temperature flue gases. In particular, within the acid dew point region, not only sulfuric acid corrosion occurs, but it is also often accompanied by particulate erosion, which accelerates equipment degradation, leading to reduced heat transfer efficiency and increased maintenance costs.
Driven by this industry challenge, an increasing number of companies are seeking more reliable material solutions, gradually shifting from conventional metals toward non-metallic and highly corrosion-resistant materials.
Corrosion resistance advantages of glass materials
Among various new materials, glass has attracted increasing attention due to its stable chemical properties and offers the following key advantages:
- Extremely strong resistance to acid corrosion, with almost no impact from sulfuric acid
- Suitable for low-temperature flue gas condensation environments
- Smooth surface that reduces dust deposition and fouling
- Long service life with high operational stability
As a result, glass is increasingly being applied in flue gas waste heat recovery heat exchanger systems, becoming an important alternative to traditional metal-based solutions.
Ruichang REGLASS® Glass Plate Heat Exchanger
The REGLASS® glass plate heat exchanger developed by Ruichang is specifically designed for flue gas waste heat recovery in refinery and petrochemical applications.
Its key features include:
- Glass plate heat transfer structure with excellent corrosion resistance
- Suitable for sulfur- and acid-containing flue gas conditions
- High-efficiency plate design to improve heat recovery performance
- Modular structure for easy system integration
- Stable operation with low maintenance requirements
By applying glass materials in industrial flue gas heat exchange systems, the Ruichang REGLASS® solution provides the refinery industry with a new option that combines corrosion resistance and energy efficiency, effectively addressing the limitations of traditional metal heat exchangers in acidic flue gas environments.
