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Introduction to extraction, refining and processing
Introduction to extraction, refining and processing
Introduction
to extraction,
refining and
processing
By William Srite
Oil, gas or coal can all be refined for the
creation of petrochemical products.
The importance of carbon chemistry
Around the 1950s, carbon chemistry was dev eloped
and we started using hydrocarbons in oil in new
ways. While advances in new uses for hydro carbons
occurred before the 1950s, such as the invention of
Bakelite, the 1950s heralded a new and powerful era for
the petrochemical ind us try. This continues to this day.
Oil and gas were broken down into constituent
parts and reassembled to make what we need. It
was discovered that oil has every element needed
to make any other organic compound. To do this,
heat is used, certain catalysts and certain properties
of physics will separate the elements and
recombine them in more useful ways. It is similar
to oil floating on water – that is a physical separation
technique that can be applied to any two
compounds that don’t mix.
Mixing is related to the stability of atoms, electrons
and valence shells and is outside the scope
of this. But when two compounds are stabile (have
the right number of electrons in their outer shell,
usually eight, but it can vary and can be as many
as 32) they don’t mix, then you can use physical
sep aration techniques, like the one des cribed above.
This allows us to make products as diverse as
Kevlar, nylon, plastic, artificial sweeten ers, rubber
tyres, and carbon fibre.
The Sauber Mercedes C 291: The use of carbon-fibre reinforced plastic allowed the driver’s cell, safety bar and roof to be made in one
piece for the first time.
Substances such as ethylene, propylene, butadiene,
benzene, toluene and xylenes are processed
in petrochemical plants into more specialised
products – and it can take more than one
step for these products to become fit for use by
downstream industries and then to be made into
familiar products. For example, it takes one operation,
albeit a complex one, to turn ethylene into
plastic polyethylene but there are more than seven
steps involved in turning benzene into Nylon, one
of the most commonly used materials in clothing
and sporting equipment manufacturing.
The science behind carbon chemistry
Let’s step back for a moment and talk about
physics and chemistry and how it works together.
“Organic” chemistry can be explained as an “artificial”
branch of chemistry that harkens back to a
time when chemists were still trying to find the
“essence of life” in elements – those that were
thought to have this “essence” were organic
elements and everything else was inorganic.
Today, we know there is no such thing as an
“essence of life”, at least not in chemical elements.
But, we still use the term and today it simply
means chemistry or chemicals that use carbon as
a building block. We’ve all heard that carbon is the
building block of life and we’ll talk about why that
is in a moment, but it is good to start with some
basic science.
First, we need to explain what an element is. An
element is a substance made from just one kind of
atom. Which is to say: you cannot reduce an
element beyond the atomic level – you can, but
particle physics is outside the scope of this. So, the
element hydrogen is an atom made from one proton
and one electron. It can also have a varying
number of neutrons, as can all atoms. In an atom,
a proton has a positive electric charge, a neutron
has no charge at all and an electron is negatively
charged. When there is an imbalance in the charge,
elements seek other elements to balance out.
The 12 Pipestill Unit at BP’s Whiting oil refinery in Indiana.
Currently undergoing modernisation, the refinery first started
operation in 1889, predating the advent of the motor car.
Carbon is such a useful element and is the basis
of all life. This is because in its natural state it lacks
four electrons in its outer shell, which makes it
very, very promiscuous and willing to bond with
almost any other element to try to fill that outer
shell with four more electrons. That’s why we can
string together long chains of hydrocarbons. Carbon
has four different places where we might attach
another element, unlike, say helium, which has a
full shell. Carbon is one of the most imbalanced
elements in organic chemistry but, thanks to
carbon chemistry, it continues to be one of the
most useful, particularly in the field of petrochemical
production.
Refineries come in many different sizes and
configurations, depending on the local market,
the types of products required and the types of
feedstocks available for processing. But all refiner-
20 WPC Guide
Petrochemicals and Refining 21