revamps for modern hydrogen plants
DESCRIPTION
This presentation highlights some of the retrofits that can be applied to Improve efficiency Increase productionTRANSCRIPT
Revamps for Modern Hydrogen Plants
By Gerard B. Hawkins
Managing Director, CEO
Introduction
This presentation highlights some of the retrofits that can be applied to • Improve efficiency • Increase production
Safe
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Effic
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Rel
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Thro
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Envi
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Retrofits for Modern Hydrogen Plants
For modern hydrogen plants, efficiency is generally good
However still drivers to maximize profit and therefore must improve either
• Plant efficiency • Plant production rate
Site Circumstances
Hydrogen plants 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
Plant Limitations
Need to address plant limitations, such as • Reformer pressure drop • Maximum tube wall temperature • Coil design temperatures in duct • Fan capacity
Basis for Study
Modern style plant with • Top Fired SMR - 368 tubes • Steam to carbon of 3.0 • Duct heat recovery is feed preheat,
steam raising and combustion air preheat
• HTS • PSA for product hydrogen purification
Plant Limitations
Three areas that can limit plant performance
Reformer
Plant Limitations
Three areas that can limit plant performance
Reformer
Convection Section
Plant Limitations
Three areas that can limit plant performance
Reformer
Convection Section
Cooling, HTS and PSA
Change Catalyst Shape and Size
By optimizing catalyst size can • Reduce pressure drop by up to 28% • Reduce carbon formation potential • Increase production by 4%
By changing to VULCAN Series VSG-Z101 can • Reduce CH4 slip and increase production by
4% • Reduce carbon formation potential • Reduce pressure drop by 22%
Reduce Steam to Carbon Ratio
By reducing SC ratio by 0.6 can • Reduce steam addition • Increase steam export • Reduce pressure drop • Gain 2-4 GJ/mmSCF • Increase production by 2%
But must be aware of • Metal dusting of WHB • Increased potential for carbon formation
Raise Outlet Reformer Temperature
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 2-4% At margin loss of efficiency Some of this efficiency can be
recouped by other revamps
Rebalancing Firing
On Terraced 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 -3 +3 Efficiency GJ/mmSCF 418 410 426
Reformer Re-tubes
The reformer 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
Reformer Re-tubes Parameter Units Case A
Base Case B
New Tubes Case C Uprate
Tube material N/A HP HP Mod HP Mod Tube OD mm 152 152 152 Tube ID mm 130 134 135 Catalyst “P” “P” “P”
H2 Production mmSCF 100 100 105 Efficiency GJ/mmSCF 406 405 407
Addition of a Pre-Reformer MP Steam
Existing Reformer
Natural Gas
Synthesis Gas
Pre-reformer
New Reheat Coil
Addition of a Pre-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 13 GJ/mmSCF
Or rate increases of 7%
Addition of an ATR
Existing
Reformer
NG Preheater NG/Steam Preheater
MUG Cooler
Oxygen Preheater
Steam Drum
MP Boiler
Natural Gas Make Up Gas
Condensate
Addition of an ATR 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 20% • More can be achieved depending on plant
design Require an oxygen plant (8 mt/hr) Energy efficiency improved by 5 GJ/mmSCF
Addition of an AGHRPR
Can add a AGHR as a post reformer Reduces steam export by 20-40% Depending on plant design allows for
plant rate increases of between 10-30% 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
VULCAN SG Delta Retrofit for Shift Vessels
By installing a specialised 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%
Other Options
Add LTS and gain 7% production Use ROG or other streams as a feed Preheat fuel Reduction in excess air in reformer Add saturator and recover low grade
heat into the process
Hydrogen Plant Revamp Capacity Increases
What capacity increase is required ?
>15%
Front End Catalyst size change VULCAN SG Delta SC Reduction Change reformer exit temperature
<5%
Front End Catalyst shape and size change Pre-reformer Re-tube Add LTS
5-15% Front End ATR AGHRPR
Hydrogen Plant Revamp Selector Efficiency Improvements
What efficiency improvement is required ?
>15 GJ/mmSCF <5 GJ/mmSCF
Front End ATR SC ratio change Fuel preheat Excess air optimization
5-15 GJ/mmSCF Front End Pre-reformer Saturator
Front End Optimized reformer catalyst loading Re-tube VULCAN SG Delta
Problems and Pitfalls Contractor and 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
Problems and Pitfalls Modelling Capability
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
Problems and Pitfalls Retrofit Details
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
Problems and Pitfalls Design Basis
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
Problems and Pitfalls HAZOPs and 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
What Can GBHE Offer?
Detail catalyst unit operation models such as the Industry 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
What Can GBHE 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
What Can GBHE 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
One Stop Shop Case Study Re-tube – Present Model
Plant Operator
Concept Engineer
Tube Supplier
Catalyst Vendor
Tube Installer
Catalyst Handler
No Communication
Detailed Engineer
One Stop Shop Case 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
Case Study - How GBHE 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
Conclusions
A number of revamps 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 has all the right expertise and knowledge to develop and design revamps