Specification for Carbon Steel Materialsfor Hydrofluoric Acid Alkylation Units

摘要

Operation of hydrofluoric (HF) acid alkylation units using primarily carbon steel construction materialhas been the norm for over 60 years. There have been few problems associated with the use of thismaterial for many years. There have been problems reported within the last 10 years where a nonuniformcorrosion phenomenon occurs leading to plant incidents. Residual elements (RE), Cr, Ni andCu in carbon steel were implicated as a potential cause for this problem. There were inconsistenciesthough claimed by others or within differing parts of the plant about this RE effect. Galvanic effectswere reported that might negate the possible beneficial use of low RE materials. This paper reports thekey results of the Joint Industry Project “Materials Specification for HF Alkylation Plant” whose primaryobjectives were to develop test and corrosion rate measurement procedures for evaluating materials inHF environments and to develop a carbon steel materials specification with respect to the levels ofresidual elements and carbon in steels for HF alkylation equipment.