Assessment of the Reliability ofFractionator Column of the Kaduna Refinery using Failure Modes Effects and Criticality Analysis (FMECA)

摘要

The reliability of a process equipment is the probability that an item will perform a required function under stated condition(s). It is an important issue in any process industry. Failure to assess the reliability of mo st process equipment had led to huge financial losses. As a result, this research aims at assessing the reliability of the Fractionator column of the Kaduna Refining and Petrochemicals (KRPC), Fluid Catalytic Cracking Unit (FCCU), using the Failure mode, effects and criticality analysis (FMECA). The failure mode effects analysis (FMEA) was firstused to identify failure modes, mechanisms, cause, effects severity of the fractionator column through its fourteen (14) sub-units(fractionator primary condenser, bottoms product cooler, debutanizer oil condenser, main fractionator, main fractionator oil drum, main fractionator reflux drum, heavy naphtha exchanger, heavy cycle oil exchanger, bottoms exchanger, BFW heater, steam generator, stripper reboiler, debutanizer reboiler, top reflux pumps). Both quantitative and qualitative criticality analyses (CA) were used to determine the effectiveness and rel iability of the unit (Fractionator column). For the qualitative analysis, items risk priority number (RPN) were computed and it was found that, six (6) of the sub-units (feed/ main fractionator bottoms exch anger, main fractionator reflux drum, main fractionator bottoms pumps, feed/ heavy naphtha exchanger, main fractionator, and main fractionator bottoms/BFW heater) had their RPN>300, with feed/ main fractionator bottoms exchanger having the highest RPN of 460. For the quantitative analysis, items criticality number (Cr) were computed and it was found that most of the sub-units had their Cr>0.002. In addition, the results of the criticality matrix showed that, fifteen (15) out of the twenty nine (29) failure modes identifiedwere above or closely below the criticality line. Therefore, the effectiveness and reliability of the unit is low. As such, sub-units with RPN>300 and failure modes above or closely below the criticality line were recommended for replacement or predictive maintenance.