Page 128 - CW E-Magazine (2-4-2024)

Point of View

isomerisation. While aromatic complexes of the
past seldom included transalkylation units, that has
changed in the last two decades, and almost all new
builds include this unit to optimise PX recovery.

Crude to aromatics
The movement towards the production of
petrochemicals, such as olefins and aromatics,
directly from crude oil, as opposed to via thermal
cracking of naphtha/ethane (for olefins) and via
traditional refining reforming (for aromatics), is being
driven by numerous factors, the most important
of which is the imbalance between demand for
oil-derived liquid fuels (diesel, gasoline) and the
more rapid growth in markets for petrochemicals.

The first of the crude oil to chemicals (COTC) projects that have been built are focussed on aromatics production, and, specifically,
PX. While much of the activity has been in China, in India, Reliance too operates integrated aromatics operations including downstream
PTA and PET resin production (to make bottle-grade resin and fibres). Over the last 3-4 years, new COTC projects in China – both private
and state-owned – are changing the scale and scope of aromatics production. The largest project has a staggering PX capacity of 9.0-mtpa,
and a few others have been built with PX capacities in the range of 5-mtpa.

But investments in these mammoth integrated projects are not without risks, and could be limited going from here. For one,
a massive shift from refining to petrochemicals could result in over-investment in the latter, with the risk that this would erode margins
in the future. Just as importantly, these projects have little or no flexibility to respond to fluctuating market conditions. Lastly, despite
their high conversion to chemicals, about 40% of the crude oil they consume still go to making fuels, which will have to find markets
in a world with steady or even shrinking demand.

Bio-based PX
The urgency to confront the impending climate crisis and its far-reaching consequences has spurred companies to seek more
sustainable, low-carbon or bio-based routes for all sorts of chemicals. Their impacts on the aromatics business and the polyester value
chain has, however, been limited so far.

Although the introduction of plastics made from biomass has been investigated and promoted for various resins, as far as PET is
concerned only monoethylene glycol (MEG), which accounts for about 30% (by mass) of the PET resin, has bio-based alternatives.
A major challenge that still needs to be commercially addressed is the conversion of the remaining 70% – i.e., PTA component, now
derived from petroleum-derived PX, to a bio-based equivalent.

Recently, a trio of Japanese companies – Mitsubishi Corporation, Suntory Holdings Ltd. and Eneos Corporation – have
announced a collaboration aimed at such a development at a commercial scale. The initiative will be based on the use of a bio-based
feedstock supplied by Finland-based Neste Cooperation, termed Neste RE, made from 100% bio-based wastes and residues, including
used cooking oil. The feedstock will be supplied to Eneos, that will produce bio-PX (on a mass balance basis) at its Mizushima Refinery
in Okayama, Japan. The bio-PX will then be converted to PTA and subsequently to PET resin for Suntory to use to make their PET bottles.

But the challenges of bio-PX production was brought home recently with the announcement by another company, Origin Materials,
that it is shifting its emphasis from making bio-PX from chloromethylfurfural (CMF) (produced from cellulosic biomass) to making
furandicarboxylic acid (FDCA) – a precursor to a specialty and a more expensive polyester, polyethylene furanoate.

Given the challenges, aromatics production will stay a petroleum-derived business for the near future!
Ravi Raghavan

128 Chemical Weekly April 2, 2024

Contents Index to Advertisers Index to Products Advertised