Common Reformer Problems
Purpose of NHT Stripper
Typical Design
Instrumentation of NHT Stripper
Other Design Issues
Indications of Problems in the NHT
Response to Reformer Upsets
ICT role in 21st century education and its challenges
Design and Operation of NHT Strippers to Protect Catalytic Reformers
1. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass
Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance
Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts /
Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals
Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries
Web Site: www.GBHEnterprises.com
GBHE Technical Bulletin CTB #55
Catalytic Reforming
Design and Operation of NHT Strippers
To Protect Catalytic Reformers
Information contained in this publication or as otherwise supplied to Users is believed to
be accurate and correct at time of going to press, and is given in good faith, but it is for
the User to satisfy itself of the suitability of the information for its own particular purpose.
GBHE gives no warranty as to the fitness of this information for any particular purpose
and any implied warranty or condition (statutory or otherwise) is excluded except to the
extent that exclusion is prevented by law. GBHE accepts no liability resulting from reliance
on this information. Freedom under Patent, Copyright and Designs cannot be assumed.
2. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass
Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance
Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts /
Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals
Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries
Web Site: www.GBHEnterprises.com
Table of Contents
Common Reformer Problems
Purpose of NHT Stripper
Typical Design
Instrumentation of NHT Stripper
Other Design Issues
Indications of Problems in the NHT
Response to Reformer Upsets
3. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass
Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance
Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts /
Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals
Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries
Web Site: www.GBHEnterprises.com
Common Reformer Problems
• H2S in feed to reformer
• Water in feed to reformer
• Bad H2O:HCl control
• Feed quality (High EP, low N+A)
• Low H2:Oil
• Organic Sulfur Compounds in feed to reformer
Purpose of NHT Stripper
• Remove the following to protect Reformer:
– H2S
– Light Ends
– Water
Typical Design
• Number of Trays
– 20-35 Trays
• Reflux to Feed Ratio
– 0.25 – 0.35
– More Reflux = More Reliability
• Feed Tray Location
– 5-10 trays from top of tower
– More Rectifying Trays can be added if needed
4. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass
Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance
Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts /
Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals
Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries
Web Site: www.GBHEnterprises.com
Instrumentation of NHT Stripper
Other Design Issues
• Fired Reboiler vs. Heat Exchanger Reboiler
– Better heat input control with Fired Reboiler
• Overhead Pressure
– Set by the vapor pressure of the liquid in the overhead receiver
5. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass
Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance
Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts /
Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals
Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries
Web Site: www.GBHEnterprises.com
Indications of Problems in the NHT
• Sulfur in the feed to reformer
– Organic Sulfur
• Reactor Problem
• F/E Exchanger Leak
• Leaking Startup Bypass Line
• Sulfur in the feed to reformer
– H2S
• Low heat input to column
– High reflux temperature
– Low reflux rate
– Low feed temperature
– Low feed rate
– Sudden change in fuel gas composition
– Sudden change in feed composition
• Low heat input to column
• Sudden change in flow rate to column
• Water issues in the column
• Water in the feed to reformer
– Increase in the water analyzer on the recycle gas
– HCl level decreases in the recycle gas
– H2S in recycle gas
– Free water in the feed to the stripper
Should be removed in the water boot on the Product Separator
– Sweet Naphtha from storage
Should be fed to the NHT Stripper to remove water
– Water refluxed back to stripper
Usually due to manual level control on the boot
Should be drained every 2-3 hours
Blocked outlet piping on boot
6. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass
Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance
Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts /
Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals
Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries
Web Site: www.GBHEnterprises.com
Other Indicators in Reformer
– Yield decreases
– Recycle gas purity decreases
– LPG make increases
– Coke make increases
Response to Reformer Upsets
Cut Temperature on Reformer
– ~900°F
– Hold until H2S is back down
Increase Chloride Injection
– Double or Triple normal rates
– Hold until H2S is back down
7. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass
Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance
Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts /
Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals
Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries
Web Site: www.GBHEnterprises.com
8. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass
Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance
Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts /
Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals
Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries
Web Site: www.GBHEnterprises.com