Chemical Engineering January 2019 - 8

microalgae and waste cooking
oil as raw material.
Hg REMOVAL
Researchers from Chalmers
University of Technology
(Göteborg, Sweden; www.
chalmers.se) have developed
a patent-pending method for
removing mercury from wastewater.
The technique, known
as electrochemical alloying, is
described in a recent issue of
Nature Communications.
In the process, a platinum
electrode is used to draw the
mercury ions out of solution to
form a stable alloy. Because
each Pt atom can " bond " with
four Hg atoms, the electrode
has a high capacity, and it can
be regenerated when loaded in
a controlled way. The method
is selective for removing only
Hg from water, and has been
shown to reduce Hg concentrations
in a liquid by more
than 99%. A company, Atium
AB (Göteborg, Sweden; www.
atium.se), has been established
to commercialize the
discovery. Currently, a prototype
device is being developed
for performing field tests.
P-RECOVERY
A 10-gal/min pilot system for
a phosphorus-recovery technology
was operated at the
Madison (Wisconsin) Metropolitan
Sewerage District dur(Continues
on p. 10)
A more efficient way to convert CO2 into
chemicals via MER
M
icrobial electrochemical
reduction
(MER) of CO2
into value-added
C02
chemicals is a potential way to
curb greenhouse gas (GHG)
emissions. MER uses chemolithoautotrophs,
which are
microbes found in the deep
sea, in caves and in hydrothermal
vents. These bacteria
get their energy by oxidizing
inorganic compounds and reducing
CO2 into organic compounds.
Typically, MER reactors
use planar cathodes with
microbes growing as a biofilm
on the surface of the cathode,
and supply CO2 by bubbling
the gas into the solution.
However, such systems have
poor efficiencies due to the
low solubility of CO2 in water and the small
surface area of the cathode.
Now, an alternative design is being developed
by the research group of professor Pascal
Saikaly, associate professor of Environmental
Science and Engineering at King Abdullah
University of Science and Technology (KAUST;
Thuwai, Saudia Arabia; https://kaust.edu.
sa). In this new design, the cathode is made
of porous nickel hollow-fibers (Ni-PHFs). In a
microbial electrosynthesis (MES) reactor (diagram),
the CO2 is pumped through the pores
of Ni-PHFs and delivered directly to the biofilm
chemolithotrophs growing on the surface of NiMaking
jet fuel from wood
L
8
ast month, construction began
on a demonstration facility that
integrates
entrained-flow
high-performance
gasification
technology and Fischer-Tropsch (F-T)
synthesis for making jet fuel from
woody biomass. The demonstration
project is being carried out by a Japanese
consortium, led by Mitsubishi
Hitachi Power Systems, Ltd. (MHPS;
Yokohama City, Japan; www.mhps.
com), with partners CEPCO, Toyo Engineering
Corp. and the Japan Aerospace
Exploration Agency (JAXA),
and support from the New Energy and
Industrial Technology Development
Organization (NEDO; Kawasaki City;
www.nedo.go.jp). The demonstration
facility is located at CEPCO's Shin-Nagoya
power station in Nagoya, Japan.
The demonstration facility will have
the capacity to process 0.7 ton/d of
woody biomass, producing about
20 L/d of " neat " biojet fuel. The consortium
plans to start trial operation
of the facility this year, and to verify
operations - including combustion
and jet-engine testing at JAXA - in
2020-2021.
On the
MHPS is
fuel-production
responsible
for
process,
the entrained-bed
gasification technology,
Toyo for micro-channel F-T synthesis
technology and the reforming of the
synthesized oil, CEPCO for equipment
operation and fuel procurement,
and JAXA for evaluation of
combustion characteristics. MHPS
has been developing coal-gasification
technology since the 1980s, and
has established high-performance
gasification furnace technology. The
gasification technology realizes uniform
and highly efficient gasification
due to the following features; oxygen
is blown at high velocity into the bottom
of the special cylindrical gasifier,
and among solid biomass, larger particles
are circulated in suspension to
be pyrolytically gasified in the lower
part of gasifier where upward gasflow
velocity is high, and smaller particles
are gasified in the upper part of
gasifier where gas-flow velocity is low.
The F-T synthesis system adopted
for this project is compact, highly efficient
and suitable for small- to medium-scale
plants, and the reactor is
easily scaled up for commercial-scale
systems, says Toyo.
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
JANUARY 2019
H+
HAc/CH4
PHFs. Initial studies showed a
77% conversion efficiency for
CO2 to methane by methanogens
when CO2 is delivered
through the pores of Ni-PHFs,
compared to 3% when bubbling
CO2 into the solution, according
to the study published
in a recent issue of Advanced
Functional Materials. In a follow-up
study, published in the
Journal of Materials Chemistry
A, the group showed that by
modifying the Ni-PHFs with
carbon nanotubes (CNTs),
an 11-fold increase in CO2
adsorption
capability
KAUST
was
achieved, along with a 76%
reduction of cathode electrontransfer
resistance,
which
nearly doubled the production
of acetate (HAc) from CO2
using Sporomusa ovata.
So far, " we have demonstrated the new
design at lab-scale, since this was a proofof-concept, "
says Saikaly. " We are currently
working on developing easier approaches
to make conductive and porous cylindrical
electrodes for large-scale applications. Also,
at the same time we are exploring alternative
anode materials (photoanodes) to reduce the
cost of operation, " explains Saikaly. " These
systems are currently being operated using
a power source. Ultimately, we can couple
this process with renewable energy sources,
such as sun or wind, " he says.
http://www.chalmers.se http://www.atium.se https://www.kaust.edu http://www.mhps http://www.nedo.go.jp http://WWW.CHEMENGONLINE.COM
Chemical Engineering January 2019

Table of Contents for the Digital Edition of Chemical Engineering January 2019
