Successful ul T Turnar narounds ounds in A AGRU RU/SRU What is - PowerPoint PPT Presentation

Successful ul T Turnar narounds ounds in A AGRU RU/SRU What is successful TA ? A successful Turnaround is NOT ONLY completing the TA scope on time, within budget and to HSE targets BUT ALSO ...... “Flawless” Shutdown, Commissioning and Start-up including a next cycle operation not hampered by flaws originating from the Turnaround

Successful ul T Turnar narounds ounds in A AGRU RU/SRU Purpose of Turnarounds : To carry out catalyst replacement. • To do Refractory repairs. • To address major maintenance issues which • involve major downtime. To inspect all burners. • To replace / upgrade Amine solutions. • To address issues related control systems and • shutdown systems. To carry out Risk Based Inspection( RBI), corrective • inspection/ Repairs. To implement modification /upgrade projects. •

Successful ul T Turnar narounds ounds in A AGRU RU/SRU Major Challenges : • Inadequate preparation of equipment /decontamination. • Turnarounds continue to consume a major part of the maintenance budget. • Many turnaround experience severe schedule slippage and cost over runs. • Acquiring sufficient, competent contractors becomes more and more difficult. • contract labor from countries with lower Q and HSE stand • Poor coordination between departments and silo mentality not working as team. • Poor quality work resulting in re-work and increased cost.

Successful ul T Turnar narounds ounds in A AGRU RU/SRU AGRU Key preparation points : Concentrate Amine solutions to most possible point • to reduce inventory volumes. Do not over circulate cold solutions to avoid HC picking. • Regenerate rich solutions 100% to avoid any acid gas • content during long storage. Always ensure draining with N2 blanketing. • Protect low pressure systems during purging with • high pressure nitrogen. Avoid keeping vent /bleeders open and leaving site • during draining. Avoid sudden cooling and vacuuming in columns to prevent • vessel /column internals damage.

Suc ucces essful ul T Tur urna narounds unds i in n AGRU/SRU Claus Catalysts Preparation for TA: • Raise the 20 C temperature in each Claus reactor and hold for 48 hours to Rejuvenate catalyst. • Swap to fuel gas mode and sweeping with stoichiometric firing. • When there is no seal leg flow from all the seal legs start increasing the excess air 1% each time. • Closely monitor Claus reactor temperature for any runaway. • Hold 4 hours in between every increase to ensure that no Sulphur left out • Check seal legs at every stage and ensure no flow. • After 8 % excess Oxygen, hold for 12 hours. • Bottom line is No Sulphur left on the catalyst before reactor is shutdown for catalyst replacement.

Suc ucces essful ul T Tur urna narounds unds i in n AGRU/SRU TGTU Catalysts- The most crucial operation: Catalyst must be oxidized before exposed to atmospheric • condition. This can be done by introducing plant air (0.5%) or steam. • When oxygen is 5% in inlet and outlet and CO2 is less then 1% • In outlet oxidation can be concluded. Reduce catalyst by hydrogen if available initially or with steam. • Carry out pre-sulfiding with acid gas if available and keep ready. • ( 2% H2S in inlet and outlet ) as catalyst active only in sulfide state. Some suppliers are supplying catalyst in activated state. • Chances of runaway reaction more. Keep emergency cooling • arrangement ready either with steam or nitrogen. Follow catalyst manufacturer procedure & temp. limit • This operation is very crucial and to be controlled well. •

Suc ucces essful ul T Tur urna narounds unds i in n AGRU/SRU Catalyst Replacement tips: • Needs to be done with extreme care due to pyrophoric issue. • Any left out Sulphur can make catalyst like cement rock. • Replacement can be done wither under inert atm. or under ambient conditions. • Integrity of Johnson’s screen needs to be ensured. • No catalyst below screen, otherwise it will end up in seal leg. • Loading should be carefully done with min. dust generation. • Dedusting operation can be done with normal air blower. • Removed catalyst can be stored in drums and should be kept wet all the time until disposal.

Suc ucces essful ul T Tur urna narounds unds i in n AGRU/SRU Thermal reactor inspection and Repairs: Acid gas lining and refractory integrity. • Decision on whether to replace whole section. • of refractory or carefully repair the cracks. Burner inspection and air distributor integrity. • Burner nozzles choke or Sulphur deposits. • Ensure seal leg drains and other nozzles are • covered to avoid debris inside. Clear cut and well executed dry out procedures. • WHB tubes ferrules replacement required or no? • Quality of refractory work is most important. •

Suc ucces essful ul T Tur urna narounds unds i in n AGRU/SRU Liquid Sulphur tank Inspection: • Pumping until minimum possible level. • Safely opening of clean out doors to drain the final draining to last drop. • Major precaution on pyrophoric iron present on steam coils. • Access to floor inspection is big challenge and depends on coil configuration. • Chances of roof corrosion due to moisture condensation if roof steam tracing not maintained. • Handling of hot Sulphur with waste generated.

Successful ul T Turnar narounds ounds in A AGRU RU/SRU Common Errors during execution: • Strainers, sprays, control valves or burners wrongly installed. • Incorrectly installed vessels internals, etc. • Purging hoses connected to choked bleeder. • Nitrogen closed to temporary Amine frack tanks. • High pressure nitrogen connected to low pressure system without pressure regulator. • LG points choked leading to wrong levels in vessel. • Bleeders /vents left open with hot condensate falling. • All blinds not removed before establishing flow.

Suc ucces essful ul T Tur urna narounds unds i in n AGRU/SRU Post TA challenges: • Engineering changes that do not result in the expected performance. • Below expectation Catalyst performance. • Contaminants in Amines and Foaming issues. • Frequent filter /strainers plugging. • Seal leg choking due to catalyst /refractory dust and no flow. • Misaligned Burners and distinguish flame patterns. • Chocked samples points. • Not meeting sweet gas specification & Environmental limits. • Sluggish control loops performance.

Suc ucces essful ul T Tur urna narounds unds i in n AGRU/SRU Finally : WORK AS A TEAM PLAN IT WELL IMPLEMENT PREVIOUS LLR EXECUTE IT FLAWLESS RUN PLANT RELIABALY UNTIL NEXT TA