30c: Corrosive Chemicals in BFW, Defective Analysing Systemsand Incomplete Treatment of Steam Systems Resulting SeriousTransfer Line Exchanger Failures

摘要

The combination of insufficient means of Boiler Feed Water (BFW) quality control,rnchemicals dosage in BFW production, incomplete steam generation system chemicalrntreatment/conservation, and pushing the demineralization plant capacity to limit, hasrnresulted in a series of serious quench exchanger damage at Borealis. As a minimumrnthe damage results in lost production and costly maintenance. In the worst case, thernquench exchanger damage is a serious safety risk and has caused bad publicity andrnenvironmental contamination when Linear Exchanger failures resulted in suddenrndumping of BFW from the cracking furnace Steam Drum to the process side causingrnserious over pressure and opening of hot section RV's, which discharged heavy oilrnvapour to atmosphere. This paper reports a number of incidents that initiated thernheavy and thorough investigation of root causes. Although it seems that the breakrnthrough of chlorine containing chemicals was the main cause of the problems, therninvestigation did reveal number deficiencies in BFW analysing systems, operatingrnmethods, chemical treatments etc. which together and individually could havernresulted same level problems sooner or later.