refining gas and the main feedstock

 5 Refining
Refining aims to provide a defined range of products according to agreed
specifications. Simple refineries use a distillation column to separate crude
into fractions, and the relative quantities are directly dependent on the crude
used. Therefore, it is necessary to obtain a range of crudes that can be
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blended to a suitable
feedstock to produce the
required quantity and
quality of end products.
Photo: Statoil Mongstad Refinery
The economic success of a
modern refinery depends
on its ability to accept
almost any available crude.
With a variety of processes
such as cracking,
reforming, additives and
blending, it can provide product in quantity and quality to meet market
demand at premium prices.
The refinery operations often include product distribution terminals for
dispensing product to bulk customers such as airports, gasoline stations,
ports and industries.
2.6 Petrochemical
Chemicals derived from petroleum or natural gas – petrochemicals – are an
essential part of today’s chemical industry. Petrochemical plants produce
thousands of chemical compounds. 

The main feedstock is natural gas,
condensates (NGL) and other refinery byproducts such as naphtha, gasoil,
and benzene. Petrochemical plants are divided into three main primary
product groups according to their feedstock and primary petrochemical
product:
Olefins include ethylene, propylene, and butadiene. These are the main
sources of plastics (polyethylene, polyester, PVC), industrial chemicals and
synthetic rubber.
Aromatics include benzene, toluene, and xylenes, which also are a source
of plastics (polyurethane, polystyrene, acrylates, nylon), as well as synthetic
detergents and dyes.
Synthesis gas (syngas) is formed by steam reforming between methane
and steam to create a mixture of carbon monoxide and hydrogen. It is used
to make ammonia, e.g., for fertilizer urea, and methanol as a solvent and
chemical intermediary. Syngas is also feedstock for other processes such as
the Fischer–Tropsch process that produces synthetic diesel.