Focused improvements in sulphuric acid plant at IFFCO, Paradeep-A case study

摘要

The 3500 MTPD X 2 nos. Sulphuric Acid Plants (SAP) at IFFCO, Paradeep had various problems associated with high dust entrainment into the waste heat boiler and first bed converter. Stoppages of plant, for catalyst screening and gas leakage arresting, and loss of heat transfer efficiency of the waste heat recovery boiler was impacting the performance of the sulphuric acid plant and in turn the entire fertilizer complex. Operation and maintenance teams carried out root cause analysis of the problem and the two main reasons were identified as: Poor Sulphur filtration; and Deformation of boiler bypass duct due to design issue Solutions to the problems were derived in-house. A new sulphur filter pre-coating system was installed, the secondary sulphur filters were revived with more effective steam flushing system and old Clean Sulphur storage tank was revamped, to release the in-service tank for muck cleaning. The ash content in the molten sulphur dropped from about 40ppm to less than 10ppm after implementation of the above measures. The production cycle between catalyst screenings is expected to increase from 180 days to more than 330 days, to match the complex turnaround cycle. The design issue of the boiler bypass duct was highlighted to the boiler manufacturer and an alternate solution, developed in-house by IFFCO, is given for detailed engineering. With implementation of this modification frequent failure of boiler bypass duct is avoided, thereby improved plant up-time and work environment.