revamps for ageing hydrogen plants

Revamps for Ageing 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

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Introduction

For older hydrogen plants, efficiency is worse than for a modern plant

To maximize profit 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 • Process side pressure drop • Maximum tube wall temperature • Coil design temperatures in duct • Steam balance • Fan capacity

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

Plant Limitations

Three areas that can limit plant performance

SMR

Plant Limitations

Three areas that can limit plant performance

SMR

Convection Section

Plant Limitations

Three areas that can limit plant performance

SMR

Convection Section

Cooling, Shifts and CO2 Removal

Change Catalyst Shape and 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%

Reduce Steam to Carbon 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

Reduce Steam to Carbon 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

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 2-5% At margin loss of efficiency Some of this efficiency can be

recouped by other revamps

Rebalancing Firing

One 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 -15 +11 Efficiency GJ/mmSCF 452 443 463

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 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

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 24 GJ/mmSCF

Or rate increases of up to 9%

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 22% • More can be achieved depending on plant

design Require an oxygen plant (9 mt/hr) Energy efficiency improved by 13

GJ/mmSCF

Addition of an AGHRPR

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

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

Addition of a Saturator

MP Steam

Existing Reformer

Natural Gas

Synthesis Gas

Heater

Saturator

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

VULCAN SG Delta Retrofit 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%

Other Options

Use ROG 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

Hydrogen Plant Revamp Capacity 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

Hydrogen Plant Revamp Efficiency 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

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 Catalysts 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

What Can GBHE Catalysts 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 Catalysts 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 Catalysts 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 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