Comparison of corrosion-resistant materials for flues, chimneys, desulfurization, and dust removal

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This post was last edited by PU3618988 on 2021-9-23 at 14:28. The corrosion protection of flues, chimneys, desulfurization systems, and dust removal systems represents a challenge in this field. Such applications require materials that are not only resistant to corrosion but also capable of withstanding high temperatures, acids, and alkalis; they need to have good corrosion resistance, be waterproof and moisture-proof, wear-resistant and impact-resistant, have a smooth surface that does not easily develop cracks, and exhibit a suitable coefficient of expansion so as to prevent detachment. Therefore, when selecting corrosion-resistant materials, a thorough evaluation and strict scrutiny are necessary to ensure reliable corrosion protection for flues, chimneys, desulfurization systems, and dust removal systems, allowing for long-term use. Based on a comparison of the corrosion-resistant materials used for flues, chimneys, desulfurization systems, and dust removal systems in China at present, a simple analysis is as follows: (1) Fiberglass-reinforced plastic (FRP) for corrosion protection: Corrosion-resistant materials made of fiberglass series have a smooth inner surface, making it difficult for deposits to form; they are also wear-resistant, acid-resistant, and have good heat resistance. However, the disadvantages of fiberglass-reinforced plastic for corrosion protection include a low elastic modulus, poor long-term temperature resistance, susceptibility to aging, and low interlayer shear strength. Overall comparison score: 0.9 points. (2) Coating corrosion resistance: The anti-corrosion coatings for flue gas use materials such as silicon carbide, boron nitride, and fine-grained alumina as fillers. These coatings are resistant to high temperatures, as well as acids and alkalis; they have a high expansion coefficient, good adhesion, excellent wear resistance, a smooth surface, impact resistance, and are less prone to cracking. They are particularly resistant to the corrosion caused by fluorine in flue gas. They are easy to apply, but their price is relatively high. Overall comparison score: 0.93 points. (3) Rubber corrosion protection: Commonly used in the domestic market are silicone rubber and polyurea; however, these materials are not resistant to high temperatures, although they have excellent waterproofing and acid-resistant properties, which makes them unsuitable for long-term use in environments with high temperatures. Overall comparison score: 0.7 points. (4) Corrosion protection using glass flake: Since the main filling material in glass flakes is SiO2, they exhibit excellent heat and acid resistance as well as high hardness; however, their adhesion is poor, and they tend to peel off in sheets. Commonly used products in the market include foam glass bricks and glass flakes. Overall comparison score: 0.83 points. (5) Acid-resistant mortar for corrosion protection: Acid-resistant mortar has good temperature and acid resistance, as well as a certain level of adhesion and a long service life; however, it has poor waterproofing and moisture-proofing properties, is prone to absorbing moisture from smoke, which leads to flaking and peeling, and is susceptible to cracking in extremely cold conditions. Overall comparison score: 0.85 points. (6) Corrosion resistance of mullite: Mullite features uniform expansion, excellent thermal shock stability, a high load softening point, low values of creep at high temperatures, high hardness, and good resistance to chemical corrosion. However, it is prone to cracking during analysis, its corrosion and water resistance are reduced, it has a large mass, and it is difficult to bond. Overall comparison score: 0.7 points. (7) Stainless steel corrosion resistance: it can withstand high temperatures, as well as acids and alkalis; however, its wear resistance is poor, its surface is smooth which results in low friction, and it has good impact resistance. Yet its welds are prone to corrosion, it is difficult to shape, and its cost is high. Overall comparison score: 0.8 points. In summary, based on the comparison of various materials used for flues, chimneys, desulfurization, and dust removal applications in terms of corrosion resistance, anti-corrosion coatings for flue gases score high in terms of all performance aspects, offering a good cost-performance ratio; they are therefore the preferred materials for anti-corrosion purposes in flues, chimneys, desulfurization, and dust removal systems in the future.