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Startup procedure

This topic contains 2 replies, has 2 voices, and was last updated by  antonio saura Cebrian 13 years, 6 months ago.

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  • #3967

    Anonymous

    Does anyone have a hold step during the startup process (after all circuits are water free)?
    If so at what temperature and for how long?

  • #7313

    We in several opportunities have maintained the unit with gasoil during 4 days recirculating (by problems in the vacuum unit) during the start up , the temperature that we maintained in the bottom section and the fraccionator was between 350 and 400.ºF (minimum temperature throughout all the system. The same way for pumparound section) If the heater or P/A pumps did not present  vibration problems when warming up the gasoil  then you could elevated this temperature something more
     
    Best regards

  • #7311

    Anonymous

    The most critical step is when ready to establish cold circulation by starting heater charge pumps through each heater and through coke drums bypass back to the fractionator. At this point fractionator bottom should not exceed 200 Deg.F and between 7-10 psig to allow removing water out of the system and avoid water flashing. This step may take a while (12-24 hrs) depending on how efficient is the water removal process. Initially each heater charge pumps should be run for a minimum 2 hours, then shutdown to drain water from all low points; ensure bottom circulation (fines removal) pumps are running to help with water removal process. Once done with one of the heater and heater charge pumps, move to next heater and second heater charge pump; be certain to drain water from pump case before starting. Repeat this for each feed pump and heater until all water is removed and pumps run continuously for at least 4 hrs. Make sure all circulating circuits are fully covered before moving to next steps: steam warm-up (up 300 Deg.F), heater pilot lighting and hot circulation with heavier feed (above 400 Deg.F); it’d take just a single branch no being commissioned and water purged to blow out everything.  

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