Refinery Process Fundamentals Curriculum

Module 2 - Distillation

Module from the Refinery Process Fundamentals Curriculum curriculum.

ATMOSPHERIC & VACUUM DISTILLATION · Learning Objectives · 1. Explain the crude distillation process from desalting through product fractionation 2. Identify typical cut points for naphtha, kerosene, diesel, AGO, and residue 3. Understand vacuum distillation principles and why reduced pressure is needed 4. Describe key operating parameters and their effect on product quality 5. Recognize common distillation problems and troubleshooting approaches · Atmospheric Crude Unit — Product Cut Points

Product	TBP Cut Range (°F)	API Gravity	Primary Use	Key Specifications	Typical Yield (vol%)	Downstream Processing
Light Straight-Run Naphtha (LSR)	C5 – 180°F	75-85°API	Isomerization feed, gasoline blending	RVP, sulfur, benzene	5-10%	Isomerization (Penex)
Heavy Naphtha	180 – 380°F	55-65°API	Catalytic reformer feed	ASTM D86 endpoints, N+2A, sulfur	15-25%	Hydrotreating → Reforming
Kerosene / Jet Fuel	380 – 480°F	42-48°API	Jet fuel, No. 1 diesel	Flash point >100°F, freeze point <-40°F, smoke point	8-15%	Merox treating or hydrotreating
Diesel / Gas Oil	480 – 650°F	32-38°API	Highway diesel, heating oil	Sulfur <15 ppm (ULSD), cetane >40, cloud point	15-25%	Hydrotreating (ULSD)
Atmospheric Gas Oil (AGO)	650 – 700°F	25-30°API	FCC or hydrocracker feed	Conradson carbon, metals, nitrogen	5-10%	FCC / Hydrocracking
Atmospheric Residue (ATB)	700°F+	10-20°API	Vacuum distillation feed	Metals (Ni+V), CCR, viscosity	25-45%	Vacuum unit
Vacuum Distillation — Key Parameters
Parameter	Typical Range	Purpose	Impact if Too High	Impact if Too Low	Control Method
Flash Zone Pressure	25-40 mmHg abs	Lower BP to vaporize heavy fractions without cracking	Reduced vaporization, lower HVGO yield	Air leakage, coking risk	Ejector/LRVP system capacity
Flash Zone Temperature	730-780°F	Vaporize VGO from residue	Thermal cracking, coke formation, color degradation	Poor HVGO yield, heavy residue	Fired heater outlet temperature
Overflash	2-5 vol% of feed	Wash section to prevent entrainment of metals/CCR	Wasted energy, heater duty increase	Metals carryover to HVGO, FCC catalyst damage	Heater outlet temp, wash bed design
LVGO Cut Point	650-800°F	Light vacuum gas oil for lube base or FCC feed	Product quality dilution	Lost yield to HVGO	LVGO draw temperature, reflux
HVGO Cut Point	800-1050°F	Heavy vacuum gas oil — primary FCC/hydrocracker feed	CCR/metals contamination from residue	Lost conversion, heavy residue increase	Draw temperature, wash oil rate
Vacuum Residue	1050°F+	Bottoms product — coker feed, fuel oil, asphalt	N/A (everything not vaporized)	Indicates poor flash zone performance	Feed quality and heater performance
Source: FOS Chief Files — Module 04 (Crude Distillation), Process Overview materials, Fractionation training documents

Source: Refinery_Process_Fundamentals_Curriculum_v1.xlsx · Sheet: Module 2 - Distillation

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