Hydrocarbon Processing - May 2022 - 26

Biofuels, Alternative Fuels and Green Petrochemicals
must invest in the recycling of single-use
plastics and must also change to renewable
feedstocks to make base monomers and
look at new less-carbon-intensive technologies
for grassroot chemical plants.
More than 75% of plastics produced
are discarded after one use and end up
in landfills and oceans. In 2018, the U.S.
produced 35 MMt of plastics, and it is estimated
that only 9% was recycled.16
The
American Chemistry Council (ACC)
member companies established a program
called Roadmap to Reuse. The
initiative's two goals were to ensure that
100% of U.S. plastics packaging will be
made to be recyclable or recoverable by
2030, and to also ensure that 100% of
U.S. plastic packaging will be designed
to be reused, recycled or recoverable by
2040. Internationally, nearly 50 global
companies have joined the Alliance to
End Plastic Waste, which is an industrysupported
non-governmental and nonprofit
organization based in Singapore.
The Alliance's goal over the next 5 yr is
to develop and deploy solutions to minimize
and manage waste and to promote
post-use solutions for plastics.
Most waste plastics end up in landfills,
with only a small percentage being
burned for heating value, with essentially
no CO2
capture. The need to stop landfilling
and to begin recycling waste plastics
is key to reducing Scope 3 emissions. Industry
must play a key role in educating
consumers and in forming partnerships
with plastic
recycling companies. The
two primary methods for plastic recycling
are mechanical recycling and chemical recycling
(i.e., advanced recycling).
Mechanical recycling involves plastics
collection, sorting by plastic type, cleaning,
shredding, melting and re-pelletizing
the plastics into new pellets. This process
is very effective for single-type plastics like
polyethylene (PE) and polypropylene.17
Chemical recycling is used for more
complex plastics and involves breaking
down the plastics to their basic components
in a liquid or gaseous state for further
processing. Pyrolysis and gasification
are the two most common methods.
Many petrochemical companies are actively
working on both approaches.
Pyrolysis can convert waste plastics
into plastic pyrolysis oil and plastic pyrolysis
gas. After treatment and removal of
oxygenates, the pyrolysis oil can be converted
to diesel fuel or used as feedstock
26 MAY 2022 | HydrocarbonProcessing.com
in an ethylene cracking furnace. Companies
are running tests using 5%-7% pyrolysis
oil from waste PE plastic as feed to
an ethylene furnace.
Gasification can convert waste plastics
into syngas (CO and H2
In addition to using recycled plastics
and capto
make synthetic chemicals
and biobased feedstocks, the chemical
industry can use renewable H2
tured CO2
). F-T chemistry
is then used to convert the syngas
to methanol, ethanol and synthetic fuels,
as well as into chemicals like ethylene
and propylene. Gasification can occur
at low pressures and high temperatures
(1,000°C-1,200°C), with the syngas after
cleanup containing approximately
39% H2
trogen.18
, 43% CO, 13% CO2 and 5% niResearch
at universities is ongoing
to use hydrocracking to break down
plastic shreds into smaller carbon molecules
that can be used to produce jet fuel,
diesel and lubricants. One process being
developed uses supercritical water to
convert waste plastics into liquids and gas
that can be further refined and upgraded
to produce new virgin plastics.19
In the U.S., the National Renewable
Energy Laboratory (NREL) is leading
efforts to study hydrogenation over catalyst
to break the C-C bonds and convert
the plastic polymer back into liquid alkanes
like ethane that can then be used
to make ethylene. The NREL is also
trying to develop recyclable-by-design
polymers that would have a closed-loop
lifecycle. This would require designing a
monomer structure that can efficiently
polymerize to the desired polymer and
then undergo selective depolymerization
to recover the monomer.17
Industry must look at using renewable
feedstocks in olefin plants to produce
ethylene and propylene. Renewable
naphtha and renewable diesel made from
biobased sources like wood biomass or
hydrotreated waste oils, fats, tall oil or
tallow could be used as feed for ethylene
plants. Using biofeedstocks for crackers
would significantly reduce Scope 3 emissions
of ethylene and its derivatives. Research
is being conducted on combining
pyrolysis and catalytic cracking for the
direct upgrading of polyolefin pyrolysis
vapors over catalysts in vapor phase to
produce base chemicals (C2
-C4 olefins).
This approach has fewer steps than the
current approach of pyrolysis of plastic
waste, treatment of the pyrolysis oil and
then cracking it in an ethylene furnace.
The process has the possibility of reducing
energy requirements and CO2
print in waste plastics recycling.20
foot(such
as ethanol and methanol) and olefins
(such as ethylene and propylene) by
using the MTO process.
The key to success of the circular
economy begins with the consumer, who
must save single-use plastic bottles for recycling.
The consumer is the first link in
this circular economy.
Takeaway: The seven pathways to
decarbonization. The oil and gas industry
will rebrand itself as an energy
provider and will transition to selling
low-carbon-intensity energy like renewable
wind and solar power, green and blue
H2
, low-carbon LNG, biofuels, renewable
diesel, e-fuels, e-gasoline and SAF.
Improving energy efficiency is the
cheapest way to reduce CO2
emissions.
For new facilities or major plant expansions,
new technologies are being considered
that have better energy efficiency
and lower carbon intensity. For catalyst
changeouts, producers should consider
newer formulated catalysts for higher
yields and lower energy intensity. Electrification
of transportation and industry
with renewable power will play key roles.
CCUS will be required for processes that
are hard to decarbonize.
The following is a summary of the seven
pathways to decarbonization. The last
three pathways support sustainability and
were discussed in this article. The first
four pathways supporting decarbonization
will be covered in Part 2, which will
be published in the June issue.
Reducing Scope 1 and Scope 2 CO2
emissions includes the following:
1. Energy efficiency: Improving
energy efficiency of facilities,
building new more efficient
facilities, and maintaining energy
recovery equipment. Producers
should stop routine flaring and
should minimize flaring at startup
and shutdown. Companies should
also use drones to detect and
track methane leaks.
2. Technology: Using new processes
and catalysts to improve yields
and reduce energy intensity.
3. Electrification: Electrifying
process equipment by using
renewable electric power (e.g.,
http://www.HydrocarbonProcessing.com
Hydrocarbon Processing - May 2022

Table of Contents for the Digital Edition of Hydrocarbon Processing - May 2022
