Petroleum Refining Engineering

Dr. TVN. Padmesh

Week 1

What Goes On In

An Oil Refinery

Agenda

Introduction

What is Crude Oil

Oil and Gas

Formation of Oil and Gas

How Do You Get from Crude Oil to

Products?

– Separations

– Chemical Reactions cont...

Agenda - Cont.

How Do You Get from Crude Oil to

Products?

– Separations

– Chemical Reactions

– Major Equipment

– Minimizing Pollution

What do The Chemical Engineers Do?

Introduction

Introduction

Energy – vital – Industrial and economic

development

Petroleum – foundation of Industrial civilization

Occurrence of crude oil – with gas

Contrary gas – Without oil

Oil/gas – varying proportions - gas/oil ratio –

chemical and physical properties.

Oil and Gas

Naturally occurring chemicals that are made

up of just two elements

Carbon & Hydrogen.

The class of chemicals based on carbon and

hydrogen are called hydrocarbons.

Oil and Gas Simplest hydrocarbon - Methane, CH4.

Other hydrocarbons like

octane and octadecane have

more complicated

structures.

Plastics are made of

molecules called polymers

that are very long chains of

hydrocarbons.

Formation of Oil and Gas

Two theories:

– Inorganic theory – action of water on metallic

carbides/atm radioactivity/cosmic radiation

– Organic theory – decomposing of Plants and

animals (algae, fungi, diatoms and

foraminifera)

» Mesozoic (225 millions), Cainozoic (65 millions)

» Predicts minimal reservoirs but more oil.

Formation of Oil and Gas

Organic theory

– Erosion of rocks and sands,

– Temperature and pressure

– Aerobic bacteria – acts as scavengers

Such complex transformation – facilitated – forming

fats, amino acids, lipids, and finally OIL and GAS.

Oil and Gas Exploration

Hydrocarbon exploration (or oil and gas

exploration) – hunt for hydrocarbons

by petroleum geologists and geophysicists.

Analysis of soil, water, rocks – geochemcial

prospecting.

Oil and Gas Exploration Types of Exploration

– Gravity survey - gravimeter

– Magnetic survey - magnetometer

– Passive seismic - seismometers

or

– Regional seismic reflection surveys

What Is Crude Oil?

Crude Oil is a liquid mixture of thousands

of organic chemicals found underground.

It is the result of organic matter decaying

over thousands of years; hence the name

fossil fuel

Crude oil is found all over the world and

varies tremendously in its density,

aromatics, sulfur, and metals content

Classification of Crude oil

Paraffins(CnH2n+2) saturated hydrocarbons with straight or

branched chains, but without any ring structure.

Cycloparaffins (CnH2n) (naphthenes), saturated hydrocarbons

containing one or more rings, each of which may have one or

more paraffin side-chains (also known as alicyclic

hydrocarbons).

Aromatics(CnH2n-6) i.e, hydrocarbons containing one or more

aromatic nuclei such as benzene, naphthalene, and phenanthrene

ring systems that may be linked up with (substituted)

naphthalene rings or paraffin side-chains.

Properties of crude oil Color: Light brown to dark brown

Sp.gr: 0.81—0.985

Boiling range : 25 – 400oC

Hydrocarbons C1- C70 (4000 compounds)

Metals: V, Fe, Ni, S - (H2S,Thiols (mercaptans), sulfides, di sulfides, poly sulfides and thiophenes).

Cause corrosion of equipments, bad odour in products, catalyst poisoning, Air pollution.

N –Indols, pyridines and quinolenes (Difficult to remove).

Oxygen compounds: Present as naphthenic acids and phenols Are corrosive in nature and cause odour. Metal: Act as catalyst poisons

Crude composition

C: 84-87%,H: 11-14%,S: 0-5%,N: 0-1%,O: 0-2%.

Refinery Operation Subdivision of Petroleum and Similar Materials into Various Subgroups

Natural Materials Derived Materials Manufactured

Materials

Natural Gas Saturates Synthetic Crude Oil

Petroleum Aromatics Distillates

Heavy Oil Resins Lubricating Oils

Bitumena Asphaltenes Wax

Asphaltite Carbenesb Residuum

Asphaltoid Carboidsb Asphalt

Ozocerite(Natural Wax) - Coke

Kerogen - Tar

Coal - Pitch

Crude oil is transported to refineries by pipelines, (more than

500,000 barrels per day), or by ocean-going tankers.

The basic refinery process is distillation, which separates the

crude oil into fractions of differing volatility.

After the distillation, other physical methods are employed to

separate the mixtures including absorption, adsorption, solvent

extraction and crystallization.

After physical separation into such constituents as light and

heavy naphtha, kerosene, light and heavy gas oils selected

petroleum fractions may be subjected to conversion processes

such as thermal cracking (i.e., coking;) and catalytic cracking.

Cracking breaks the large molecules of heavier gas oils

into the smaller molecules that form the lighter, more

valuable naphtha fractions.

Reforming changes the structure of straight-chain

paraffin molecules into branched-chain iso-paraffins

and ring-shaped aromatics. The process is widely used

to raise the octane number of gasoline obtained by

distillation of paraffinic crude oils.

Down stream Process • Products

– Distillation and processing » Fuel gas

» Petrol

» LPG (domestic gas)

» Naphtha

» Kerosene

» Diesel

» Fuel Oil

» Lubricants

» Waxes and

» Petroleum coke