高温气相条件下硫酸氢铵与硫酸铵对20#碳钢的腐蚀行为研究

Corrosion Characteristics of Carbon Steel in High Temperature Gas Containing Ammonium Bisulfate and Ammonium Sulfate

通过失重法研究了20#碳钢在含有硫酸氢铵(ABS)和硫酸铵(AS)高温气相中的腐蚀行为。采用SEM/EDS和XRD表征手段分析了腐蚀后碳钢试片的微观形貌变化及腐蚀产物的物相组成。结果表明:在108~282℃范围内,ABS和AS均对碳钢有腐蚀性,ABS的腐蚀性更为严重;随着ABS和AS浓度的增大,腐蚀速率加快;随着温度的升高,腐蚀速率减缓。推测腐蚀机理为:由于ABS和AS溶液的酸性,碳钢主要发生H^+的酸性腐蚀,亦存在氧腐蚀;阳极反应生成的Fe^(2+)发生系列次生反应生成Fe的氧化物,并且Fe2O_3、Fe_3O_4与硫酸铵盐发生相互作用生成(NH_4)Fe(SO_4)_2等复盐。

The corrosion of carbon steel in high temperature gas containing ammonium bisulfate（ABS） and ammonium sulfate（AS） was studied by means of weight loss method,SEM/EDS and XRD.Results show that in the range of 108~282 ℃,the ABS and AS in flue gas are both corrosive to carbon steel,while ABS causes more serious corrosion.As the concentration of ABS and AS in gas phase increases,the corrosion rate is accelerated; with the rising gas temperature,the corrosion rate is slowed down.The corrosion mechanism is speculated as follows： due to the acidity of ABS and AS solution,H^＋acid corrosion is the main corrosion of carbon steel,but oxygen corrosion also takes place.The anode reaction generated Fe^2＋ may then induces the secondary reaction to form series of iron oxides,thereafter ammonium sulfate salt interacts with Fe2O3 and Fe3O4 to generate ammonium sulfate（NH4）Fe（SO4）2 and other double salts.