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Case 3 – Increasing hydrogen partial pressure - Case 3a – Diesel hydrotreater increase H2/oil ratio? purify hydrogen? change liquid feed? decrease pressure.

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Presentation on theme: "Case 3 – Increasing hydrogen partial pressure - Case 3a – Diesel hydrotreater increase H2/oil ratio? purify hydrogen? change liquid feed? decrease pressure."— Presentation transcript:

1 Case 3 – Increasing hydrogen partial pressure - Case 3a – Diesel hydrotreater increase H2/oil ratio? purify hydrogen? change liquid feed? decrease pressure drop? -Case 3b – Naphtha hydrotreater increase H2/oil ratio? purify hydrogen? change liquid feed? decrease pressure drop?

2 Case 4 – Pressure Drop -Situation 1 – Poor catalyst loading or poor start-up procedures -Situation 2 – Internals, catalyst strength or corrosion impurities coming into the catalyst bed

3 Case 4 – Pressure Drop Possible causes for pressure drop -Reactor - coking, polymerization, particles (FeS), catalyst loading, maldistribution, metal poisons -Exchangers- salts deposition, coking, polymerization, particles deposits

4 Case 4 – Pressure Drop HR mm DENSE LOAD 3/4" inert balls 1/4" inert balls 3/4" inert balls ACT mm 1/4" inert balls ACT mm HMC mm Reasons for this high pressure drop build-up?? Reasons for the higher pressure drop in the second bed??

5 Case 4 – Pressure Drop

6 Catalyst grading bed – trickle bed reactors

7 Case 4 – Pressure Drop Scale baskets – Gas phase bed reactors Scale baskets are needed in order to provide longer resistance to pressure drop build up. The role of the basket is not intended to retain the fines which should be trapped on the top layer of inert balls, but to act as a fuse in case of pressure build up They should remain clean Inert balls 3/4" Inert balls 3/4" Catalyst bed Vapors + fines Vapors free of fines Fines accumulation

8 Case 4 – Pressure Drop Pressure drop must be corrected for process conditions, as gas and liquid flowrates for example Delta P measured Delta P predicted

9 Case 4 – Pressure Drop Feed + H2 Desulphurized product + H2 After start-up a very high pressure drop Was observed across the reactor

10 Case 5 – Hydrogenation Activity S + 2H 2 + 2H 2 S + 2H 2

11 Case 5 – Hydrogenation Activity Température (°C) % HDA Soufre effluent (ppm) T1T2 HDS Régime thermodynamique (HDA) Régime cinétique (HDA) Equilibre thermodynamique HDA

12 quench (0 t/h) four lit 1 lit 2 lit 3 0 R1 0 R2 0 R1 0 R2 Opération normale Diminution de la température dans le dernier lit R1 R2 température Case 5 – Hydrogenation Activity

13 Case 6 – Unit Shut-Down In the race of increasing severity in sulphur specifications - NZSD, optimising the unit shut-down and scheduling it as a non routine event is as important for the overall unit performance as a Formula 1 pit stop can be to wining reactor cool down catalyst unloading catalyst loading distribution tray removal (mechanical details) catalyst drying reactor inspection under air atmosphere regenerated catalyst pool catalyst activation method Dedicated flow-bins - FUTURE

14 Case 6 – Unit Shut-Down reactor Pre-heat exchangers Furnace maxi cold HP separator By pass to be opened at 150°C Compressor stripper dryer LP separator GO to storage Cooling loop for hydrotreatment units Gasoil cooling loop Air coolers   To LP separator From HP separator stripper Pre-heat exchangers Normal operating circuit


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