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

Successful ul T Turnar narounds

• unds 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

• unds 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

• unds 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

• unds 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.
• f 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
• n 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

• unds 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