在合成气制乙二醇装置环境（温度116~128℃，硝酸质量分数2%~20%）中对304L不锈钢进行3次长周期现场挂片浸泡腐蚀试验，研究了304L不锈钢的长周期腐蚀行为。结果表明：经过不同条件下的3次长周期挂片浸泡腐蚀后，304L不锈钢发生了不同程度的晶间腐蚀及腐蚀减薄，且在硝酸质量分数2%~8%、温度116℃、时间156 d条件下不锈钢的腐蚀程度最严重，不锈钢出现晶粒脱落现象，其全面腐蚀速率大于2 mm·a^-1，腐蚀程度为严重腐蚀。硝酸还原反应器催化剂中的钯是急剧加速304L不锈钢腐蚀的主要介质，与304L不锈钢形成电偶效应，从而加速304L不锈钢的腐蚀，在该工艺条件下不推荐304L不锈钢作为脱重塔底区域的材料。

The long-period corrosion behavior of 304L stainless steel was investigated by three long-period field hanging coupon immersion corrosion tests in the environment of a syngas ethylene glycol plant with temperatures of 116-128 ℃ and nitric acid mass fractions of 2%-20%. The results show that different degrees of intergranular corrosion and corrosion thinning occurred in 304L stainless steel after three long-period hanging coupon immersion corrosion under different conditions. The corrosion degree of stainless steel was the most serious under the condition of nitric acid mass fraction of 2%-8%, temperature of 116 ℃ and time of 156 d, and grain peeling occurred; the general corrosion rate was greater than 2 mm·a^-1, and the corrosion degree was serious corrosion. Pd in the catalyst of nitric acid reduction reactor was the main medium that rapidly accelerated the corrosion of 304L stainless steel. Pd and 304L stainless steel formed galvanic effect, thereby accelerating the corrosion of 304L stainless steel. 304L stainless steel was not recommended as the selection material for the de-heavy tower bottom area under the process condition.