Chemical Engineering January 2022 - 6

greenhouse gas (GHG) emissions.
Through the technologycommercialization
agreement,
TechnipFMC will utilize and integrate
the membrane technology
licensed from Petronas as part
of its production portfolio in projects
worldwide, outside China.
The technology, which removes
CO2 and H2S by using " wetted
membranes, " is said to be 30%
more efficient than existing gastreatment
processes and can reduce
GHG emissions by significant
amounts. The membrane
has potential applications in both
offshore and onshore hydrocarbon
production environments.
NEW MEMBRANE MODULE
Toray Industries, Inc. (Tokyo,
Japan; www.toray.com) has developed
an exceptionally robust
hollow-fiber ultrafiltration-membrane
module that is suitable
for purification and concentration
processes in the food-andbeverage
and biotechnology
sectors. The module operates
in steam (125°C) and hot water
(90°C) environments, and can
be steam sterilized.
Toray leveraged its highstrength
polyvinylidene fluoride
hollow-fiber membrane technology,
which is already used in
water-treatment applications, to
develop a new module that employs
an " outside-in " type crossflow-filtration
design. Crossflow
filtration is a common technique,
whereby feed passes parallel to
the membrane surface and prevents
turbidity from accumulating.
Pressure losses from this
design are just one-third those
of " inside-out " type that is normally
used by food companies,
says Toray. With the new design,
it is possible to filter and concentrate
highly turbid or viscous liquids,
which is challenging with
conventional membranes.
The new module has a large
membrane area, which reduces
the number of modules needed,
reduces the space requirements
by 50% and can potentially lower
cleaning and equipment costs
by more than 20%, Toray says.
SELF-HEALING CEMENT
Superior Energy Services
(Houston; superiorenergy.com
has launched RestoreCem , a
self-healing cement system.
RestoreCem's self-healing behavior
enables it to regain its
(Continues on p. 7)
6
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
JANUARY 2022
Extracting high-quality MgSO4 from
seawater desalination brine
A
team of researchers, led by professor
Myoung-Jin Kim, from Korea Maritime
and Ocean University (Busan,
South Korea; www.kmou.ac.kr), has
developed a process that recovers calciumfree
magnesium sulfate from seawater desalination
brine (SDB). The process, described in
a recent issue of Desalination, takes advantage
of the difference in solubility of MgSO4
and CaSO4 in ethanol.
In the process (diagram), alkali is first
added to SDB to precipitate Mg(OH)2. The
magnesium is concentrated by the addition
of sulfuric acid. The eluate then undergoes a
two-step addition of ethanol. First the ethanol
dosage is adjusted so that only CaSO4
is precipitated. After the Ca2+ has been removed,
ethanol is further added to precipiPre-precipitation
Concentration
tate
the high-purity MgSO4. The magnesium
recovery efficiency is 67%, producing 15.8 kg
of MgSO4·7H2O from 1 ton of brine.
Because the purity of the recovered
MgSO4 was up to 99.8%, it could be used to
re-mineralize fresh water after the seawater
desalination process. According to a cost assessment
of the process, high-purity MgSO4
produced from seawater desalination brine is
expected to be preferred over other MgSO4
products that are used in the pharmaceutical
and food markets, which require high-purity
and economic feasibility.
" Since we have already developed a sophisticated
seawater desalination process
to address the world's water needs, why not
couple it with the beneficial process of mineral
extraction, " says Kim.
Precipitation
One-step process
Ethanol
Alkali
H2SO4
Seawater
desalination
brine
Mg(OH)2(s)
Mg eluate
Two-step process
1st
ethanol
Ca-free
Mg eluate
MgSO4(s)
2nd
ethanol
High-purity
MgSO4(s)
Korea Maritime and Ocean University
Quantifying varnish removal in lubricated systems
I
n lubricated systems, varnish and deposits
can form on metal surfaces as lubricant
oils degrade, often leading to inefficient
operations and equipment failure.
There are many chemical cleaning products
to break down varnish, but the effectiveness
of these compounds in a particular system is
difficult to quantify. To aid in selecting appropriate
varnish-removing solutions for a particular
application, Chevron Lubricants (San
Ramon, Calif.; www.chevronlubricants.com)
has partnered with the University of California
at Merced (www.ucmerced.edu) to develop
one of the industry's first testing system designed
to study and compare the varnish removal
efficiency of chemical cleaners.
The new test module includes an oil circulation
unit, an imaging system and an imageanalysis
algorithm, which enables quantitative
evaluation of varnish removal efficacy for
chemical flushing fluids. An oil sample is heated
and pumped through a specially designed test
cell holding a metal plate containing a quantity
of varnish film. The imaging system monitors
varnish removal as the image-analysis algorithm
generates corresponding data points,
which are corroborated against weight measurements
of the plate.
" We can study the varnish removal efficiency
of chemical cleaners with different
chemistries and treat rates at controlled operating
conditions. Removal efficiency can
be quantified as the total varnish removed
over a given time or the rate of varnish removal.
This approach also provides qualitative
information about the varnish removal
mechanisms for each cleaner using in situ
videos of removal and post-test analysis of
the varnish particles trapped on a downstream
filter, " says Zhen Zhou, senior formulator
for Chevron.
Currently, the test system uses standard
testing coupons, but the team is developing
a module that is capable of measuring
varnish removal on irregularly shaped metal
parts in the field, such as valves and bearing
pads, explains Zhou. The team believes that
the testing unit could also be applied in other
applications involving thin films and chemical
circulation in the coatings and paint industry.
Re-mineralization
of freshwater
https://www.kmou.ac.kr/ https://www.toray.com/ https://www.chevronlubricants.com/ https://www.ucmerced.edu/ https://superiorenergy.com/ http://WWW.CHEMENGONLINE.COM
Chemical Engineering January 2022

Table of Contents for the Digital Edition of Chemical Engineering January 2022
