Agenda 1. Composition & Molecular Types 2. Characterization of Petroleum Products 3. Crude Oil Properties 4. Distillation Analysis 5. Exercise Problems

Refinery Feedstocks Crude Oil Complex mixture of hydrocarbons Dissolved gases to non-volatiles (1000°F+ boiling material) C1 to C90+ Composition Element Wt% Carbon 84-87 Hydrogen 11-14 Sulfur 0-5 Nitrogen 0-0.2 Other elements 0-0.1

Crude Oil Molecular Types Paraffins Carbon atoms connected by single bond. Other bonds saturated with hydrogen. Naphthenes Ringed paraffins (cycloparaffins). All bonds saturated with hydrogen. N-Butane Cyclopentane

Crude Oil Molecular Types Aromatics Six carbon ring (multiple bonding). All bonds are unsaturated. Olefins Usually not in crude oil. Formed during processing. At least two carbon atoms connected by double bond. Naphthalene Benzene 1-butene

Characteristics of Petroleum Products Refinery Coke Vacuum Resid Atmospheric Resid Crude Oil Gas Oil Jet Fuel/Diesel Gasoline LPG Average Carbon Number (Atoms per Molecule) Hydrogen/Carbon Atomic Ration

Characteristics of Petroleum Products Petroleum Fractions Hydrocarbon Range Boiling Range (°C) Boiling Range (°F) Light gases C2-C4 -90 ~ 1 -130 ~ 30 Gasoline (light and heavy) C4-C10 -1 ~ 200 30 ~ 390 Naphtha (light and heavy) C4-C11 -1 ~ 205 30 ~ 400 Jet fuels C9-C14 150 ~ 225 300 ~ 490 Kerosene C11-C14 205 ~ 225 400 ~ 490 Diesel fuel C11-C16 205 ~ 290 400 ~ 550 Light gas oil C14-C18 255 ~ 315 490 ~ 600 Heavy gas oil C18-C28 315 ~ 425 600 ~ 800 Wax C18-C26 315 ~ 500 600 ~ 930 Lubricating oil >C25 >400 >750 Vacuum gas oil C28-C55 425 ~ 600 800 ~ 1100 Residuum >C55 >600 >1100

Crude Oil Assay Distillation Analysis Indicates the quality of the crude oil feedstock. Based on the amount of material that boils in a particular temperature range. Represents expected products from crude & vacuum distillation. Amount of data depends on laboratory analysis. Quality Measures Gravity, API Characterization factor Sulfur content, wt% Pour point, F (C) Carbon residue, wt% Salt content, lb/1000 bbl Nitrogen content, wt% Metal content, ppm

Crude Oil Properties Distillation Analysis Amount collected from batch distillation at the indicated temperature. Most useful is TBP (True Boiling Point). Standardized tests: ASTM D86, D1160, …etc. API Gravity A measure of gravity or density. Arabian crudes are classified as follows: Arabian Heavy (29 API and less) Arabian Medium (29-32 API) Arabian light (32-34 API) Arabian Extra Light (36-41 API) Arabian Super Light (49-52 API)

Oil Classification Using Assay Data Key Fractions, °API No. 1 (760 mmHg) 482-527 °F No. 2 (40 mm Hg) 527-572 °F Paraffin 40 ° 30 ° Paraffin, intermediate 20-30 ° Intermediate, paraffin 33-40 ° Intermediate Intermediate, naphthene 20 ° Naphthene, intermediate 33 ° Naphthene <33 ° <20 °

Crude Oil Characterizations Paraffinic (West Texas) Little heavy aromatic material (asphaltic). Good for paraffin wax manufacture. Quality Lube stocks. High grade kerosene. Naphthenic (Louisiana) High quality gasoline (octane). Poor lubes & kerosene. Aromatic (Maya) High quality gasoline & asphalt. High levels of poisons; sulfur & nitrogen. Residue is asphaltic.

Crude Oil Properties

Crude Oil Properties Characterization Factor Watson factor (UOP) Indication of crude oil aromaticity and paraffinicity. Less than 10 is highly aromatic. Up to 15 is highly paraffinic. Correlation Index (U. S. Bureau of Mines) Individual fractions from crude oils. Straight-run paraffins have a CI of 0 and benzene have a CI value of 100.

Crude Oil Properties

Crude Oil Properties Sulfur Content Takes the form of hydrogen sulfide (H2S), mercaptans, sulfides, disulfides. Odorous and toxic. “Sour” vs. “sweet” — ~0.5 wt% cutoff. Restrictions on sulfur in final products. Nitrogen Content Takes many forms (e.g. Cyanides) Odorous and corrosive. In heavy gas oil, acts as an inhibitor to FCCU and HCU catalyst. Usually tolerate up to 0.25 wt%.

Crude Oil Properties Metals Content Arsenic, nickel, vanadium, copper, …etc. Poison catalysts. Nickle and vanadium affect FCCUs and HCU. Carbon Residue Carbon residues from specific ASTM tests. D524 — Ramsbottom. D189 — Conradson (CCR). Related to asphalt and lubricating oil content. Pour Point Rough indicator of paraffin vs. aromatic content. Specific flow test. The lower the pour point the lower the paraffin content. Salt Content Generally associated with emulsified water.

Sample Crude Oil Assay

Distillation Analysis ASTM D86 Gasoline, turbine fuels, naphtha, kerosene, gas oil and distillate fuel oils. Atmospheric pressure. No hotter than 650°F to minimize cracking. Correlations to correct to TBP basis.

Distillation Analysis ASTM D1160 Heavy petroleum products (650°F+). Vacuum conditions — 10 to 40 mmHg. Correlations to correct to atmospheric.

Simulated Distillation Analysis ASTM D2892 & D5236 This method uses a 15 plate column operating under a reflux ration of 5:1. Starts at atmospheric pressure. Maximum temperature of 650 F. Switch to ASTM D5236 at o.1 mmHg pressure. Maximum temperature of 1000 F. TBP temperatures — wt% basis

Distillation Curve & Fractions

Distillation Curve & Fractions Temperature, F Volume percent vaporized

Assay Data Manipulation Boiling Point Manipulation Correct temperatures to atmospheric pressure. Correct temperatures to TBP basis. Put onto cumulative basis for the whole crude. Cumulative Yield Curve “S” shaped curve — yield vs. boiling point. Linearized using Gaussian normal probability functions. Standardized Cut Points Volume increments. Cut points corresponding to crude tower products. Temperatures associated with the lightest pure components.

Assay Data Manipulation Properties for Fractions Properties inferred from measured trends. » Relative density / specific gravity / API gravity » Sulfur content » Carbon residue Properties from correlations » Molecular weight / molar mass » Critical properties & acentric factor » Heat of combustion ^ ^

Assay Data Manipulation Adjusting Temperature for Pressure Equation form of Maxwell-Bonnell charts (1955)

Interconvert D86 & TBP Temperature Vol% a b IBP 0.9167 1.0019 10 0.5277 1.0900 30 0.7492 1.0425 50 0.8920 1.0176 70 0.8008 1.0226 90 0.9490 1.0110 95 0.8705 1.0355

Interconvert D1160 & TBP Temp. D1160 temperatures at 10 mm Hg are converted to TBP temperatures at 10 mm Hg — graphical method. D1160 temperatures at 50% & higher equal to the TBP temperatures. 0% to 10%, 10% to 30%, & 30% to 50% D1160 temperature differences converted to TBP temperature differences. Vol% Distilled Range a b c d Max ∆T 0%-10% 2.23652561 -1.39334703E-2 3.6358409E-5 1.433117E-8 144 °F 10%-30% 30%-50% 1.35673984 -5.4126509E-3 2.9883895E-5 -6.007274E-8 180 °F

Interconvert D1160 & TBP Temp.

Average Boiling Point for a Fraction Five types are defined in the API Technical Data Book Volume average boiling point Mass average boiling point Molar average boiling point Cubic average boiling point Mean average boiling point Use either mid-boiling point or boiling point at mid-cumulative amount