How Hydrocarbons Become Petrochemicals – It’s Complicated

In the petrochemical industry, a hydrocarbon is an organic compound made up exclusively of hydrogen and carbon atoms.  Hydrocarbons are the building blocks for a wide range of products covering everything from adhesives to detergents and solvents.  Best of all, they are derived from petroleum. Hydrocarbons are produced during the refining process.

Turning hydrocarbons into petrochemicals requires a 4-step process.  Though the details may vary from one product to the next, here are the basics:

Step #1: Preparing the Feedstock

The feedstock in any manufacturing process is that collection of raw materials necessary for production.  For the purposes of turning hydrocarbons into petrochemicals, we’re talking about crude oil and natural gas liquids.  Feedstock components need to be prepared before any production can begin.

Crude oil is refined to create several fractions, like naphtha.  These fractions act as key feedstocks for different petrochemicals.  As for natural gas liquids, we are looking to create things like butane and propane.  They are also valuable feedstocks.

Step #2: Material Separation

The feedstock preparation step doesn’t produce pure, isolated feedstocks.  Rather, the process produces materials requiring further separation.  We can use crude oil as an example again.  Separating the various components can be achieved through distillation.

The oil is heated and passed into a distillation chamber.  In the chamber, additional heat and pressure are applied while the various components evaporate at their particular boiling points.  Lighter fractions rise to the top of the chamber while the heavier fractions settle down below.  They can be individually captured, isolating each fraction from the rest.

Step 3: Fraction Conversion

Conversion is the third step.  It is arguably the most complicated step in the process.  Conversion requires transforming the captured hydrocarbons into petrochemical building blocks.  There is more than one way to do it, so methods are chosen based on the materials we are working with and the building blocks we are seeking to create.

Here are four common options for converting fractions:

  1. Cracking – Cracking breaks large hydrocarbon molecules into smaller units.  This is usually done with a combination of heat, pressure, and some sort of catalyst.  Steam cracking is a fairly common practice.
  2. Reforming – Reforming produces aromatic hydrocarbons by rearranging a fraction’s molecular structure.  Through reforming, we can create products like benzene and toluene.
  3. Isomerization – Isomerization is similar to reforming in that molecular structures are rearranged.  However, there is no altering of a fraction’s chemical formula with this process.
  4. Alkylation – Alkylation Is the practice of combining smaller hydrocarbons to create larger molecules.  The resulting materials can create things like high-octane gasoline and specialty chemicals for manufacturing.
Following fraction conversion, there is but one step remaining.  That step is petrochemical production.

Step 4: Petrochemical Production

Converted hydrocarbons are ready to become petrochemicals.  Our customers combine the hydrocarbons they purchase from Trecora with other materials to manufacture their chemicals of choice. Those chemicals include:
  • Olefins (used extensively in manufacturing plastics)
  • Aromatics (used to manufacture resins, solvents, etc.)
  • Synthesized gases (converting gases into products like methanol)

Just like proteins are the building blocks of muscle tissue, hydrocarbons are the building blocks of petrochemicals.  Without them, modern manufacturing would look nothing like it does.  Transforming hydrocarbons into petrochemicals is complicated.  But it is also worthwhile.  As a petrochemical processor, we pride ourselves on producing high-quality hydrocarbons for manufacturing and industrial use.