Effect of tungsten on the corrosion behavior of sulfuric acid-resistant steels for flue gas desulfurization system

Abstract

Flue gas desulfurization systems (FGDs) are operated in severely corrosive environments that cause sulfuric acid dew-point corrosion. The corrosion behavior of low-alloy steels was tested using electrochemical techniques (electrochemical impedance spectroscopy, potentiodynamic tests, potentiostatic tests), and the corrosion products were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical results showed that alloying W with small amounts of Sb, Cu, and Co improves the corrosion resistance of steels. The results of surface analyses showed that the surface of the steels alloyed with W consisted of W oxides and higher amounts of Sb and Cu oxides. This suggests that the addition of W promotes the formation of a protective WO3 film, in addition to Sb2O5 and CuO films on the surface.

Compositional design of low carbon sulphuric acid dewpoint corrosion resistant steel and corresponding anticorrosive mechanism

“…In the metallurgical, electric power generation, petrochemical and other industrial fields, sulphur (S) containing fuels are burnt, producing sulphur and nitric oxides: SO 2 , SO 3 and NO x . [1][2][3][4] When the exhaust gas temperature drops below temperatures corresponding to a dewpoint, or when the gas is in contact with a low temperature wall such as flues, smokestacks, boiler air preheaters and other facilities exposed to exhaust gas, 5,6 these acid gases combine with moisture to form highly concentrated acids. This 'dewpoint' corrosion causes serious corrosion failures with both general corrosion and pitting corrosion occurring.…”

The superhydrophobic coating with low‐temperature dew point corrosion resistance on an acid‐resistant steel substrate prepared by the electrodeposition method

“…From the high‐resolution analysis of the spectral peak of Cr 2p3/2, three subpeaks are obtained, as shown in Figure 13d, where the peak at the binding energy of about 578.6 eV corresponds to Cr 2 (SO 4 ) 3 , [ 23 ] the peak at 576.4 eV corresponds to Cr 2 O 3 , [ 24 ] and the peak at 577.3 eV belongs to the position of Cr(OH) 3 . [ 14 ] As can be seen in Figure 13e, the spectrum of Fe 2p has two typical Fe subpeaks at a binding energy of 713.3 eV for Fe 2p3/2 and 724 eV for Fe 2p1/2, [ 25 ] which correspond to Fe 2 (SO 4 ) 3 [ 26 ] and Fe 2 O 3 , [ 27 ] respectively.…”

“…It is clear from the position of the binding energy that Fe 2p3/2 represents Fe 2 O 3 [ 32 ] and Fe 2p1/2 represents FeOOH. [ 26 ] In addition, dissolved Fe 2+ from ND steel can form iron oxides such as FeOOH on the surface. [ 25 ] The spectra of the Cu (Figure 14b) and Sb (Figure 14c) elements are characterized by the two distinct 2p peaks and 3d peaks, respectively.…”

“…[ 25 ] The spectra of the Cu (Figure 14b) and Sb (Figure 14c) elements are characterized by the two distinct 2p peaks and 3d peaks, respectively. The spectra of Cu 2p3/2 (933.2 eV) and Cu 2p1/2 (952.7 eV) are assigned to CuO [ 26 ] and the spectra of Sb 3d5/2 (531 eV) and Sb 3d3/2 (540.2 eV) are assigned to Sb 2 O 5 . [ 33 ] At the same time, the oxidation peaks of Fe, Cu, and Sb can also be found in their corresponding positions in the spectrum of O 1s (Figure 14d).…”

Micro‐alloys precipitation in NiO‐ and CoO‐bearing enamel coatings and their effect on adherence of enamel/steel

“…Sulfuric acid dew point corrosion occurs in sectors in flue gas treatment systems, such as gas‐gas heat exchangers (GGH for short), flue and chimney in electric power, metallurgy, and petrochemical industries . Generally, protection of GGH is mainly divided into two categories: (i) Using corrosion resistant steel, such as ND (09CrCuSb), S‐TEN (12CuSb), TAICOR‐S (12CrCuAl) and CRIA (10CrCu); (ii) Employing low carbon steel with a protective coating, in which enamel coating attracts much attention.…”