Attachment 2 Presentation Slides HOVENSA Refinery Fuel Oil Burning– Explanation and Limitations of NOXProduction Vince D’Ippolito, HOVENSA

### HOVENSA Refinery Fuel Oil Burning Explanation and Limitations of NOx Production Vince D'Ippolito 4/17/09 Saint Croix, VI" 

### HOVENSA

HOVENSA Fuel Oil Burning



## YiIlv does HOVENSA burn fuel oil (No. 6 Oilll 1. Refinery is located on an island - no natural gas pipeline 2. Fuel gas produced atthe refinery is less than energy required 3. Majority offuel gas atthe refinery is produced by2 units: FCC and Coker 60% oftotal refineryfuel gas production 4. HOVENSA uses all the fuel gas it produces 5. Excess light gases (H2, off gas, etc.) must be disposed in the refineryfuel gas system. Includes process upsets with units that use H2 as a reactant and unplanned shutdowns of heaters. 6. Not practical to store fuel gas in refinery oron island 7. Refinery propane production is not sufficientto handle fuel gas system changes 8. Cokerfuel gas production is not constant - varies by as much as 

### 200/0 in 1 hour every day due to the normal Coker process 9. Dailyvariation in fuel oil usage can be 1%to 40% oftotal fuel consumed in the refinery depending on operating units 1

### %

# =refineryfuel consumers are reduced 

### 400/0

# =FCC/Coker planned or unplanned shutdown
1HOVE'NSA HOVENSA Fuel Oil Burning 

# Oil flame Oil 

### Vs. Gas Firing 

# Gas flame

Heaters have multiple burners - crude unit has 2 heaters with 18 burners in each 2

### HOVENSA HOVENSA Fuel Oil Burning 

### Conventional fuel gas and oil combination burner

REGEN TILE

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J -sn:.L\1 (.Y.S,) n-;:::L.D 011, (P.S. ) Side View Top View (looking down in heater)

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### HO\IEN'SA HOVENSA Fuel Oil Burning 

### Conventional fuel gas and oil combination burner

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I STE.lJI (\.8.) n='1=n OIL IVS,) Side View Burner before heater installation

Oil Tip 4

### HO\IENSA HOVENSA Fuel Oil Burning 

### Conventional fuel gas and oil combination burner

Gas Tip Oil Tip Total number of holes and hole size different for each fuel type

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### HOVENSA HOVENSA Fuel Oil Burning 

## Wb.Y does HOVENSA burn fuel oil and fuel gas in the same heater? 1. Fuel gas production is not a constant rate each dayor during the day: A. Small variations in feed composition to FCC and Coker can result in large changes in fuel gas production B. Coker unit is a cyclical unitwith fuel gas production variation C. Feed rate changes occurto fuel gas producers: FCC and Coker D. Fuel gas production and composition varies because of day-night air temperature variation: propane composition changes in fuel gas system E. Fuel oil permit limits on units are less than total fuel required 2. Only select heaters have permits to burn fuel oil 3. Switching burners from oil to gas requires step processing to prevent surging the refineryfuel gas system pressure and releasing fuel gas into the flare system Occurs at sunset/sunrise every day, when refinery units are shutdown/started, or as a result of large throughput changes Oil/gas burnerswitching must be done carefullyto prevent heaterstacksmoking Successful control offuel system requires concurrent burnerswitching across multiple units SWitching burners from oil to gasfuel is best handled by same heateroperator
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### HOVENSA HOVENSA Fuel Oil Burning 

## WIlY does HOVENSA require heater burners that can "co-fire" oil or Q!l§1 "co-fire" means that the burner can either use oil or gas without switching the burner or adding burner parts, but is not used to fire both fuels atthe same time at HOVENSA. Some burners in the heaterwill operate on oil and some will operate on fuel gas. 1. All ofthe burners are in operation at all times - can not have idle burners 2. When a burner is removed from service or not used: A. heater is less efficient due to air leakage through out-of-service burner - uses morefuel B. flame height ofthe remaining burners becomes higher - potential to touch overhead tubes ortube supportfailure. C. flame stability decreases - flame close to heatersides causing tube support failure, tube overheating/failure, tube coking D. distribution of heat in the heater is uneven - can causing heatertube coking 3. Fuel gas system is dynamic requiring flexibilityforthe burners to be switched quickly - can not change out "gas only" or "oil fired only" burners quickly 4. Individual heaters/units can be shutdown for maintenance - limits the quantityof fuel oil burners available forfuel gas swings
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### HOVENSA HOVENSA Fuel Oil Burning

w!!y 

### doesn't HOVENSA use "emergency back up oil gun" burners? "emergency back up oil gun" means thatthe burner normally burns fuel gas, but can burn oil by either: A. adding the oil fired partto the burnerwhile it is in service - switching fuels requires maintenance modification ofthe burner B. the burner manufacturer has added an oil fired partto a gas only design Oil and gas are notfired atthe same time 1. HOVENSAdoes not usethis type of burner 2. Fuel gas system requires quickand frequent fuel system changes to many burners 3. Advanced knowledge ofthe gas to oil switching timing is needed to schedule workers to remove/add the oil parts.

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### iiOVEN5A HOVENSA Fuel Oil Burning

Whatwould be required to have oil specific and gas specific burners in each ofthe process heaters that burns fuel gas and fuel oil? 1. Total numberof burners would haveto be increased by approximately 

### 1000/0 2. Heaters would have to be re-designed and re-built Cabin style heaters: Heaterwould have to be lengthened Internal heatertubes would have to be lengthened Outside structures (pipe, piperacks) would have to be moved Burner manufactures would set burner spacing for NOx guarantee Cylindrical heaterswould have to be demolished and re-built

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## · HO\IEN"SA

HOVENSA Fuel Oil Burning


### Questions

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