### Ron McGihon (ExxonMobil) 

# FCC Naphtha Desulfurization – New Developments
Why Reduce Sulfur in Petrol

**0 100**  **200 300**  **400 500**  **600 700**  **800 900**  **1000**

**Pre 2000 2001 BS II 2005 BS III 2010 BS IV Petrol**  **Diesel**



### • **Low sulfur in petrol reduces emi ssions of toxins into atmosphere**  **50 ppm**

# Sulfur In Gasoline FCC Naphtha the Primary Source

**FCC Naphtha**  **Reformate Alkylate**  **& Other Oxygenates**  **Portion of Gasoline**  **volume Sulfur**  **contributed**



# EMRE Technologies for Quality Fuels

HDC + MIDW 

# EMRE HYDROFINING Waxy Feeds Distillate Heavy Feeds ULSD HDC LCO Upgrading MIDWTM MDDWTM GO-finingTM ULSD + HDHDC ULSD + MAXSATTM Residfining 

### Naphtha FCC Naphtha OCTGAIN SM Hydrofining SCANfiningTM

# FCC Naphtha Desulfurization - Topics ♦ Technology Overview ♦ Chemistry and Catalyst ♦ Design Flexibility ♦ Ongoing Improvements



# Desulfurizing FCC Naphtha ♦ FCC naphtha contains olefins that contribute high octane to gasoline pool ♦ Conventional hydrodesulfurizing of FCC naphtha results in olefin saturation and octane loss ♦ SCANfining uses a very selective catalyst to minimize olefin saturation and thus minimize octane loss

# SCANfining Flow Scheme

**PRODUCT C-4** 

**OFFGAS**
**Product Stripper**  **Main Reactor**  **Recycle Gas** 

**Zeromer Reactor**  **Amine Scrubber** 

**PURGE Diolefin**  **Saturator**

**FEED FEED**  **REACTION PRODUCT RECOVERY**  **GAS RECYCLE H**  **2**



### 10-15 100.1 Hydrogen, Nm3/m3 Naphtha yield, vol % 95-98 15-25 0.6 – 1.5 Sulfur reduction, % Olefin reduction, % Octane loss (R+M)/2 500-1500 10-50 Feed Sulfur, ppmw Product Sulfur, ppmw **Typical single stage design**  

# Typical Performance

# Sulfur Removal Chemistry

**Recombinant Recombinant**  **Mercaptans Octane** 

**Loss** 

### Mercaptans **Mercaptans Thiophenes**  **Thiophenes Olefins**  **Olefins R-H + H**  **2 S**  **Hydrotreat**

**R-R Hydrotreat**  **R-SH Reversion**  **R-H + H 2** **S Hydrotreat**  

### R-SH

**R = R R = R**  **S R** 
**H 2** 

### S **+** 

# Mercaptans Limit SCANfining I Selectivity

♦ Reversion mercaptan levels governed by process conditions ♦ Alternative process designs control mercaptan content in product **SCANfining I Processing Full Range Ca t Naphtha: Low S, High Olefins** 

**% Olefin Saturation 0**  **20 40**  **60 80**  **100 120**  **140**

**0 10 20 30 40 50**  **60 70 wppm Sulfur**  **Total Sulfur Non-Mercaptan Sulfur**  

### Mercaptan Sulfur

# Preferred Regions for SCANfining Options**Feed Sulfur Two Stage Preferred** 

**SF I Preferred** 

### Technology Selection Depends on Feed Sulfur and Olefins **For Ultra-Low Product Sulfur Targets**

**Feed Olefins** 

### ZEROMER



# SCANfining Flow Scheme

**PRODUCT C-4** 

**OFFGAS**
**Product Stripper**  **Main Reactor**  **Recycle Gas** 

**Zeromer Reactor**  **Amine Scrubber** 

**PURGE Diolefin**  **Saturator**

**FEED Feed**  **Reaction Product Recovery**  **Gas Recycle H**  **2**

# Selective HDS Catalysts The Heart of the SCANfining Process ♦ RT-225 designed specifically for selective FCC naphtha HDS  Minimizes olefin saturation / octane loss  Proven activity and selectivity maintenance  First commercial SCANfining use began in early 1995 

### ♦ Ongoing Catalyst Development Program  Next generation catalyst for main reactor commercialized  Higher activity and selectivity  ExxonMobil is committed to support own refineries and licensees 

### ♦ Process Design Improvements  Designs tailored to specific situations  Installed units utilize single-stage, Zeromer and multi-stage designs



### 7-10 X *0.5 Y * 0.5 95-98 10-15 0.3 – 0.8 500-1500 10-40 **Typical Zeromer** 

10-15 X Y Hydrogen, Nm3/m3 Treat Gas, Nm3/m3 Catalyst volume, m3 95-98 15-25 0.6 – 1.5 Sulfur reduction, % Olefin saturation, % Octane loss (R+M)/2 500-1500 10-40 Feed Sulfur, ppmw Product Sulfur, ppmw **Typical single stage**  

# Typical Performance – with Zeromer

# Zeromer Advantage ♦ Significant reduction in CAPEX & OPEX  Reduced compressor size  Reduced reactor size  Better octane preservation  Lower hydrogen consumption 

# ♦ Ability to handle high sulfur feeds without feed fractionation



# Reliability **Reliability** Reliability and Commercial Experience

# Port Jerome SCANfining Unit 5 years on first charge Port Jerome SCANfiner First Cycle Unit has been 100% available since December 1999 startup End of Run Temperature (Design)

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Years on OilReactor Temperaturefor Constant % HDS



# Automatic Bed Bypass Technology Run Length Protection 

# ♦ Fouled catalyst bed bypass technology ♦ Developed to mitigate pressure drop buildup across catalyst bed ♦ Proprietary ExxonMobil technology

# Automatic Bed Bypass Technology

**Bed Segment with Bypass** 
**Main Catalyst Bed(s) Liquid and Gas** 

**Liquid and Gas** 

# Automatic Bed Bypass Internals Applied Commercially in Many Different Services

♦ Key design feature for run length assurance ♦ Proven in numerous ExxonMobil and licensee units

 Naphtha hydrotreaters  Diesel hydrotreaters  Cat feed hydrotreaters  Hydrocrackers  Vacuum Residfiner 

### ♦ Eliminated fouling limitations **0 20**  **40 60**  **80 100**  **120 140** 

**0 5 10 15 20 25 Relative Time** **Relative Reactor Pressure Drop**  **w/o bypass w/ bypass** 

# Commercial Experience - 38 Units
**New Retrofit**  **ExxonMobil Licensees** 
**SCAN I SCAN II ..**  **FR Naphtha ICN and/or HCN**  **N. America Europe, Asia, ME**  **New/retro Ownership** 

**Design Feed**  **Location** 

# In Summary ♦ FCC naphtha must be desulfurized  To meet emissions standards  Special technology needed 

# ♦ ExxonMobil-KBR offer low cost reliable solution for sulfur reduction ♦ Continuing developments to enhance technology

# Thank you very much... 

# Questions?