渣油加氢装置湿硫化氢腐蚀及防护

分析了加氢装置中硫化氢的来源并阐述了高温硫化氢、湿硫化氢的腐蚀机理和形态,重点强调了湿硫化氢腐蚀主要为应力腐蚀开裂以及给工程带来的危害。文章以典型的渣油加氢装置为例,分析了渣油加氢装置中包括原料油、反应流出物和循环氢脱硫等高压系统的腐蚀部位及介质环境。结合湿硫化氢的腐蚀机理、腐蚀类型和工程实际应用情况,论述了渣油加氢装置3个高压系统中湿硫化氢的腐蚀形式,并提出了选材标准、原则和常用的防腐蚀措施。还分别从材料的生产方式、交货状态和纯净度等方面从满足抗硫化物应力腐蚀开裂和抗氢诱发裂纹的角度提出了制造、热处理和表面缺陷等方面的具体要求。并提出防腐蚀的关键是要清楚生产装置中相关系统的介质,尤其是压力、温度、介质组成、介质质量浓度、相变和pH值等细节,才能做到正确选材。

Corrosion of Wet Hydrogen Sulfide in Residue Hydrotreating Unit and Protection

The sources of hydrogen sulfides in the hydrotreating unit were analyzed and the corrosion mechanisms and corrosion forms of both high-temperature hydrogen sulfide and wet hydrogen sulfide were described.The wet hydrogen sulfide corrosion mainly occurred in the form of stress corrosion cracking,which could bring out various safety hazards to engineering projects.In a case study of a typical residue hydrotreating unit,the corrosion location and medium environment of the high-pressure systems of the residue hydrotreating process,especially the feedstock system,the reaction effluent system and recycle hydrogen desulfurization system were analyzed.In view of the wet hydrogen sulfide corrosion mechanisms,corrosion types and practical applications in engineering projects,the corrosion forms of the wet hydrogen sulfide in three high-pressure systems of the residue hydrotreating unit were discussed,and the material selection criteria,material selection principles,and common anti-corrosion methods were proposed.The specific manufacturing requirements,heat treatment requirements,and surface defects treatment were presented to meet the requirements of SSCC and HIC resistances of materials in respect of the material production,delivery status and purity.It is finally concluded that the critical aspect of anti-corrosion is to find out the medium conditions in the related systems of the production unit,including,in particular,the pressure,temperature,medium compositions,medium concentration,phase change,pH value and other details.Only in this way can the correct selection of material be made.