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Revamps for Ageing Hydrogen Plants
The document discusses retrofitting aging hydrogen plants to improve efficiency and production rates through various technical modifications, such as optimizing catalysts and steam ratios, adding pre-reformers, and redesigning exhaust systems. It highlights potential increases in performance, efficiency, and production, while also addressing the complexities and necessary considerations for successful implementations. GBHE Catalysts is positioned to provide comprehensive engineering and design support for these retrofitting projects.
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Revamps for Ageing Hydrogen Plants
- 1. Revamps for AgeingHydrogen Plants By Gerard B. Hawkins Managing Director, CEO
- 2. Introduction This presentationhighlights some of the retrofits that can be applied to • Improve efficiency • Increase production Safety Efficiency Reliability Throughput Environment
- 3. Introduction For olderhydrogen plants, efficiency is worse than for a modern plant To maximize profit must improve either • Plant efficiency • Plant production rate
- 4. Site Circumstances Hydrogenplants have a wide range of site circumstances Is there value for steam on the site ? What are the downstream users ? What is the contract basis for the H2 supply When conducting a revamp these need to be carefully considered GBHE is in a unique position to fully understand these issues and design revamps accordingly
- 5. Plant Limitations Needto address plant limitations, such as • Process side pressure drop • Maximum tube wall temperature • Coil design temperatures in duct • Steam balance • Fan capacity
- 6. Basis for Study Old style plant with • Top Fired SMR - 500 tubes • Steam to carbon of 3.9 • Duct heat recovery is feed preheat and steam raising • HTS • LTS • Wet CO2 system • Methanation
- 7. Plant Limitations Threeareas that can limit plant performance SMR
- 8. Plant Limitations Threeareas that can limit plant performance SMR Convection Section
- 9. Plant Limitations Threeareas that can limit plant performance SMR Convection Section Cooling, Shifts and CO2 Removal
- 10. Change Catalyst Shapeand Size By optimizing catalyst size can • Reduce pressure drop by up to 27% • Reduce carbon formation potential By changing to VULCAN Series VSG-Z101 can • Reduce CH4 slip and increase production by 5% • Reduce Tube Wall Temperatures by 10°C • Reduce carbon formation potential • Reduce pressure drop by 29%
- 11. Reduce Steam toCarbon Ratio By reducing SC ratio by 0.6 can • Reduce steam addition by 19 mtphr • Increase steam export by 9 mtphr • Reduce pressure drop by 23% • Reduce TWT by 14°C • Gain 5.3 GJ/mmSCF
- 12. Reduce Steam toCarbon Ratio Or increase plant rate • Reduced DP • Gain 1.8 GJ/mmSCF • In some cases can increase rate above base case But must be aware of • Metal dusting of WHB • Increased potential for carbon formation
- 13. Raise Outlet ReformerTemperature Many operators run to a false tube wall or outlet header temperature By analysis of reformer operation, this limitation can be eliminated Improves production by 2-5% At margin loss of efficiency Some of this efficiency can be recouped by other revamps
- 14. Rebalancing Firing OneTerraced Wall or Side Fired reformers, the firing can be rebalanced Either improves efficiency or steam raising capacity on in some cases can increase rate Parameter Units Case A Case B Case C Firing at Top % 50 40 60 Firing at Bottom % 50 60 40 Steam Export Mt/hr 0 -15 +11 Efficiency GJ/mmSCF 452 443 463
- 15. Reformer Re-tubes Thereformer tubes do have to be replaced and therefore have to be considered as a consumable By replacing with an improve metallurgy, a thinner wall tube can be used This provides a wide range of process and operability benefits
- 16. Reformer Re-tubes Parameter UnitsCase A Base Case B New Tubes Case C Uprate Tube material N/A HK40 HP Mod HP Mod Tube OD mm 114 114 114 Tube ID mm 84 96.4 96.4 Catalyst “P” “P” “P” “P” H2 Production mmSCF 100 101 109 Efficiency GJ/mmSCF 430 428 433
- 17. Addition of aPre-Reformer MP Steam Existing Reformer Natural Gas Synthesis Gas Pre-reformer New Reheat Coil
- 18. Addition of aPre-Reformer To obtain maximum benefit requires • Reheat of effluent - an achieve very high preheat and reheat temperature with latest generation of pre-reforming catalyst can recover more heat from duct and reduce furnace duty significantly • Must model effect on duct to ensure that existing demands for heat are fulfilled (HP Steam Raising) Can allow for efficiency improvements of up to 24 GJ/mmSCF Or rate increases of up to 9%
- 19. Addition of anATR Existing Reformer NG Preheater NG/Steam Preheater MUG Cooler Oxygen Preheater Steam Drum MP Boiler Natural Gas Make Up Gas Condensate
- 20. Addition of anATR or Secondary Either in parallel (ATR) or in series (secondary) • Parallel ATR has less impact on the main plant • Main plant can run when ATR off line Can increase production rate by 22% • More can be achieved depending on plant design Require an oxygen plant (9 mt/hr) Energy efficiency improved by 13 GJ/mmSCF
- 21. Addition of anAGHRPR Can add a AGHR as a post reformer Reduces steam export capacity significantly Depending on plant design allows for plant rate increases of between 20-40% Also potential energy efficiency gains Steam Hydrocarbon Feed HDS Fuel Steam Generation and Superheating Steam Generation and Superheating Combustion Air Pre-heat Reformed Gas Process Additional gas + steam feed Gas Heated Post- Reformer Waste Heat Boiler HDS Preheat Mixed Feed Preheat
- 22. Addition of Saturator Recovers low grade heat into the process Maximizes quality and quantity Up to 13 mt/hr of export steam can be generated Link with CO2 solution change
- 23. Addition of aSaturator MP Steam Existing Reformer Natural Gas Synthesis Gas Heater Saturator
- 24. Combustion Air Preheat Allows for improvement in heat recovery from the duct Most suitable for top fired furnaces but can be applied to side fired furnaces • Cost is higher due to complexity of ducting Will reduce fluegas flow and therefore heat available in the duct - must model this carefully Improve plant efficiency by 30 GJ/mmSCF Can allow for rate increase
- 25. VULCAN SG DeltaRetrofit for Shift Vessels By installing a specialized support system can reduce pressure drop significantly GBHE can offer the VULCAN SG Delta which can reduce pressure drop by around 50% Allows plant rate increases of up to 3%
- 26. Other Options UseROG or other streams as a feed Use low methanol LTS catalyst Preheat fuel Change CO2 solution Install quench upstream of LTS Reduction in excess air in reformer
- 27. Hydrogen Plant RevampCapacity Increases What capacity increase is required ? >15% Front End Catalyst size change VULCAN SG Delta SC Reduction LTS Quench <5% Front End Catalyst shape and size change Pre-reformer Re-tube Change reformer exit temperature 5-15% Front End ATR AGHRPR
- 28. Hydrogen Plant RevampEfficiency Improvements What efficiency improvement is required ? >15 GJ/mmSCF<5 GJ/mmSCF Front End ATR SC ratio change Fuel preheat Excess air optimisation 5-15 GJ/mmSCF Front End Pre-reformer Saturator CA preheat Front End Optimised reformer catalyst loading Re-tube VULCAN SG Delta
- 29. Problems and Pitfalls Contractorand Contract Must carefully select partners • Must have domain knowledge Design and operations • Must have correct tools • Must be able to supply correct level of detail for study Must select appropriate contract type • LSTK or Reimbursable • Both have advantages and disadvantages
- 30. Problems and Pitfalls ModellingCapability Must use correct tools Model the whole plant using a flowsheeting package • Must include all unit operations • Must develop a robust base case • Must validate against plant data • Must understand deviations • Then develop the retrofit case
- 31. Problems and Pitfalls RetrofitDetails The customer and engineering contractor must determine • Precise scope for retrofit • Responsibilities • Key deliverables • A detailed and consistent design basis • Time scale and milestones • Review schedules Summarize as Good Project Management
- 32. Problems and Pitfalls DesignBasis Engineering contractor must conduct on site visit • Must work with client • Collect representative plant data • Model and understand plant data • Discuss discrepancies and eliminate • Identify bottlenecks • Identify opportunities for improvement These form the core of the design basis
- 33. Problems and Pitfalls HAZOPsand Commissioning Must use systematic review method to highlight potential problems with retrofit • HAZOPs are a well proven system • Requires time and buy in from all parties • Results as good as quality of people ! Retrofit will change plant parameters • Must update PFDs and P&IDs • Must update operating instructions • Must take additional care during start up
- 34. What Can GBHECatalysts Offer? Detail catalyst unit operation models such as the world leading VULCAN REFORMER SIMULATION program • Also models for other catalyst unit operations Detail non-catalyst unit operation models such as • Heat exchange programs • Finite Element Analysis • CFD modelling One stop shop
- 35. What Can GBHECatalysts Offer? Domain Knowledge • Operations Many staff have operations background Troubleshooting clients plants • Design Many staff have detailed engineering background Engineers work on design daily Work with leading contractors on front end and detailed design issues Catalysts Consulting Services Domain Knowledge
- 36. What Can GBHECatalysts Offer? Can supply any level of detail for retrofit Scoping studies • Front End • What are the best options Front End Engineering • Flowsheets and design of key components Detailed Engineering • Design of all components of retrofit A one stop shop for your revamp requirements
- 37. One Stop ShopCase Study Re-tube – Present Model Plant Operator Concept Engineer Tube Supplier Catalyst Vendor Tube Installer Catalyst Handler No Communication Detailed Engineer
- 38. One Stop ShopCase Study Re-tube – “One Stop Shop” Model Plant Operator GBHE Concept Engineer Tube Supplier Tube Installer Catalyst Handler Detailed Engineer Seamless Minimum Cost Maximum Benefit
- 39. Case Study How GBHECatalysts Works Strong position due to credibility from previous work Uprate projects • Feasibility Process Uprate study on Naphtha 115%, 130% or 150% cases • FEEP (Front End Engineering Package, what would be needed?) 115% FEEP adopted • Option evaluations and natural gas feed conversion Followed by full Engineering Detail Design Also additional design work on Desulfurization Design Study
- 40. Conclusions A numberof retrofits have been presented that are suitable for application to hydrogen plants They address all the key limitations that hydrogen plants typically suffer from To take full benefit from some of these retrofits, others may also be required GBHE Catalysts has all the right expertise and knowledge to develop and design retrofits