储油罐腐蚀特征及失效分析

以克拉玛依石化公司储油罐腐蚀为例,对储罐腐蚀的类型及部位进行了分析.储罐腐蚀可分为罐顶腐蚀、罐底内侧腐蚀及罐底外侧腐蚀.罐顶外壁主要为大气腐蚀或因废水引起的电化学腐蚀,其内壁为因结露而引起的电化学腐蚀;罐底内侧沉积水中含有H2S,CO2,Cl-和泥砂引起点蚀;罐底外侧为潮湿环境下引起的电化学腐蚀.因此,提高罐顶排水和保温层防水性能十分必要,同时应采取必要的防腐蚀措施和改进油罐基础的设计.

Corrosion Features of Oil Storage Tanks and Failure Analysis

The corrosion types and location of oil storage tanks are analyzed on the basis of oil storage tank corrosion in Kelamayi Petrochemical Company. The corrosion can be divided into tank top corrosion and internal and external surface corrosions of tank bottom. The external corrosion of the top plates is mainly atmospheric corrosion or electro-chemical corrosion caused by the waste water. The internal corrosion of the top plates is the corrosion caused by the formation of dews. Pitting corrosion occurs on the internal surface of bottom plates as the result of action of H 2S, SO 2, Cl- and sludge in the settled water at the bottom of the tank. The corrosion on the external surface of the bottom plates is the electro-chemical corrosion caused by the wet environment. Therefore, it extremely necessary to have a good water drainage at the top of the tank and improve the anti-water permeation performance of tank insulation. In addition, necessary corrosion protection measures should be adopted and tank foundation design improved.