Chemical Engineering December 2020 - 6

and a roughly 12% reduction of the
required energy for desalination, " according
to the abstract. The technology
has been patented.
SULFURIC ACID CATALYST
Haldor Topsoe A/S (Lyngby, Denmark;
www.topsoe.com) has introduced
a new catalyst for converting
SO2 into sulfuric acid. VK38+ is a
new potassium-promoted catalyst
that has been proven to have higher
activity than any other commercial
potassium-promoted catalyst, regardless
of which converter bed it
is used in. The catalyst has already
been demonstrated in two industrial
plants. Through its higher activity,
VK38+ has the potential for enhanced
performance, higher efficiency and
reduced climate footprint. VK38+
provides these performance results
without the cost increases that are
associated with many Cs-catalyst solutions,
says Topsoe. Calculations for
VK38+ show an up to 40% reduction
of long-term catalyst spending and a
payback time of just a few months.
TS-1 CATALYST
Titanium silicalite-1 (TS-1) has been
used for nearly 40 years for the catalytic
conversion of propylene and
hydrogen peroxide into propylene
oxide (PO), but the mechanism for
the conversion has not been well
understood. Now, a team of researchers
from BASF SE (Ludwigshafen,
Germany; www.basf.com),
ETH Zurich (Switzerland), the Uni(Continues
on p. 7)
Tubular sieves for extracting lithium from brines
R
6
esearchers from the College of Chemical Engineering,
Nanjing Tech University (Nanjing, China;
www.njtech.edu.cn) have developed a new strategy
for forming lithium ion-sieve membranes to
achieve an efficient recovery
of lithium ions
from brine or seawater.
Spinel lithium manganese
oxide ion-sieves
have been considered
the most promising adsorbents
to extract Li+
from brines or seawater.
The researchers have
reported a lithium ionsieve
which was loaded
onto tubular alpha-Al2O3
α-Al2O3
Dry
Li source
Mn source
Nanjing Tech University
Acid
Li+
lithium ion-sieve was obtained after acid pickling. The
lithium manganese oxide could be uniformly loaded not
only onto the surface of alpha-Al2O3 substrates but also
inside the pores. The equilibrium adsorption capacity
of the lithium ion-sieve
was 22.9 mg/g. The
adsorption balance was
reached after 12 hours.
After five adsorption
cycles, the adsorption
capacity of the lithium
ion-sieve was 60.88%
of the initial capacity.
For the dynamic adsorption-desorption
process,
the lithium ionsieve
exhibited excellent
Calcination
L-AA
Brine
Li+
Desorption
α-Al2O3
supported
Li+ ion-sieve
membranes
ceramic substrates by dipping crystallization and postcalcination
(diagram).
The lithium manganese oxide (Li4Mn5O12) was first
synthesized onto tubular alpha-Al2O3 ceramic substrates
as the ion-sieve precursor and the corresponding
adsorption performance for Li+, with the Li+ adsorption
capacity of 9.74 mg/g and a manganese ion (Mn2+) dissolution
loss rate of 0.99%. After three dynamic adsorptiondesorption
cycles, 80% of the initial dynamic adsorption
capacity was still maintained.
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM DECEMBER 2020
Methane pyrolysis process uses renewable
electricity to split CH4 into H2 and carbon black
S
ite commissioning is underway
at a facility in Nebraska that uses
plasma pyrolysis to generate hydrogen
gas and carbon black
from natural gas without any local carbon
dioxide
emissions. The developer,
Monolith Materials (Lincoln, Neb.; www.
monolithmaterials.com), scaled up the process
at the site after operating a pilot plant
from 2014 to 2018.
Natural gas
Plasma furnace
The natural gas
is super-heated
by electricity
Hydrogen
There is no
flame, creating
a CO2-free
process
Carbon black
Monolith Materials
In a second phase of the project, currently
in the front-end engineering and design
(FEED) stage, the pyrolysis-derived H2
will be combined with N2 from the atmosphere
to make ammonia for agricultural
fertilizer via a Haber-Bosch process.
In Monolith's proprietary methane-pyrolysis
process, natural gas is fed into a reactor
along with other process gases, where
it is heated to between 1,500 and 2,000°C
by electric plasma. The heat splits the CH4
into H2 and solid carbon in the absence of
O2. " The reaction conditions, with close attention
on the fluid dynamics of the gases
and the aerodynamics of the solids, allow
us to finely control the particle morphology
of the carbon black at the nanoscale, and
also to avoid unwanted side reactions, " explains
Rob Hanson, co-founder and CEO
of Monolith.
To achieve H2 production at commercial
scale, the company met the challenge of
running the plasma pyrolysis reactor
reliably for long periods at the high
temperatures required for methane
splitting. The carbon black produced
by the reaction is sold into
the vehicle tire market and used for
battery materials, while the H2 could
be used for ammonia or in the petroleum-refining
industry.
The environmental advantages of
the electric plasma-pyrolysis process
are significant. Production of
H2 in this way uses only one-seventh
the power required to produce
H2 via conventional electrolysis of water,
and purified water is not required. And
if the electricity to generate the plasma
comes from renewable sources, it would
allow fully emissions-free production of
H2. Natural gas for the process could
also be sourced from landfill biogas,
Hanson notes.
Full commercial-scale production of
what is termed " turquoise ammonia " (NH3
produced using H2 from methane pyrolysis)
at the facility is expected in 2024.
http://www.topsoe.com http://www.monolithmaterials.com http://www.basf.com http://www.njtech.edu.cn http://WWW.CHEMENGONLINE.COM
Chemical Engineering December 2020

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