Most 1st Quartile & Pacesetting Refiners have a robust predictive / preventive system to assure ‘zero incident’ in the complex. Some of the best practices used are - MIQA (Mechanical Integrity and Quality Assurance) analysis, deployment of IOWs (Integrity Operating Windows), Online probes to track vibration, corrosion, fouling, higher temperature, toxic release, etc. Yet, occasionally incident occurs. Here are a few case studies dealt by professionals of AshPhil in the past to assess the root cause of such incident and system updated to avoid such recurrence.
1. Process line hammering was noticed in lube complex which restricted the unit intake. The vibration of the line was pretty serious and as all efforts by operating crew to eliminate by changing operating condition in that segment did not give desired result. The engineers of AshPhil who worked as trouble shooting team identified the root cause of vibration arising from two phase flow formation as a result of piping elevation change. Process cooling was modified including waste heat recovery exchanger design alteration to mitigate the issue. The unit intake could then be raised to close to 200% of original design.
2. Sour water stripper reboiler fouling can become an issue especially in an integrated refining complex with units viz. cat cracker, delated coker, etc., route unstripped sour water to SWS for stripping of H2S and other dissolved gases. Heavy fouling was noticed in the reboiler of SWS column. All units continued to say their process is steady and no such contaminants were present. However, on deeper analysis by AshPhil engineers in a refinery in the past revealed high level of ingress of high boiling oil (heavy VGO type) from Coker complex. Further, it was seen that the use of demulsifier within coker complex was stopped as cost saving measure with out looking in totality. The same was corrected and reboiler fouling in SWS unit became non-existent.