Chemical Engineering April 2019 - 7

Chementator
This P-recovery process is market-ready
PowTech
t
2019
this
month
(Nuremberg, Germany), Glatt Ingenieurtechnik
GmbH (Weimar, Germany;
www.glatt.com) introduced a
waste-free process that recycles the phosphorus
from sewage-sludge ash to produce
ready-to-use, high-quality fertilizers. The
market-ready process fulfills the legal obligation
of the German fertilizer ordinance
(DüMV), which requires waste-disposal
companies to recover phosphorus, and can
recover virtually all of the phosphorus from
the ash of incinerated sewage sludge.
In the first step of the two-stage PHOS4green
process (diagram), a suspension is
produced from the phosphate-containing
ash, a mineral acid (for example, phosphoric
acid) and, depending on the objective, other
components. This acid treatment macerates
the ash, and converts insoluble phosphates
into a form that can be absorbed by
plants. In the second step, the suspension
is sprayed into a fluidized-bed granulator,
which is blown with hot air. As the water
evaporates, the granules grow in size before
being discharged. Product is screened to
separate granules of the desired size from
over- and undersized solids, which are recirculated
to the granulator.
" The process recycles 100% of the ash, "
says Jan Kirchhof, senior sales manager
Process and Plant Engineering at Glatt. " By
flexibly adapting the recipes, a wide variety of
fertilizers, including complex varieties (NP, PK,
Glatt
A
Mill
Screen
Final product
NPK), can be produced, which can be placed
on the market as new products, " he says.
The process has been tested on various
sludge ashes, from mono-incineration
plants, in a pilot plant at Glatt's Technology
Center in Weimar. The pilot unit can produce
approximately 60 kg/h of standard
fertilizer. Several engineering phases have
already been completed for the first largescale
commercial plant, which is now in the
approval phase. Groundbreaking for
this
project is anticipated in the next few weeks.
The modular system can be configured for
the desired capacity, with various configurations
handling a capacity of 10,000-40,000
ton/yr of sludge ash. Nevertheless, smaller
and larger plant set-ups are possible.
A new membrane for forward osmosis
M
any desalination technologies
have been developed, but they
usually require a large amount
of energy. Forward osmosis (FO)
has the potential to become an excellent
alternative desalination technology due to
its lower energy consumption. Nano structured
materials have also attracted attention,
particularly metal organic frameworks
(MOFs), due to their exceptional separation
properties, controllable pore sizes, adsorption
affinities and high porosity. To use an
MOF as an effective membrane, an MOF
is deposited onto an inorganic support to
provide mechanical strength and chemical
resistance. Increased attention has been
given to a subclass of MOFs: the zeolitic
imidazolate frameworks (ZIFs) that consist
of zinc or cobalt ions coordinated by an
imidazole-based linker. Under this group,
ZIF-8 has been the most commonly studied
for various separation applications.
Now a team from Universiti Teknologi Malaysia
(Skudai, Malaysia; www.utm.my) has
carried out the in-situ synthesis of ZIF-8
membranes using the solvothermal process
onto alumina hollow fiber in the presence of
ZnO, NiO and polydopamine (PDA). In addition,
the different molar ratio of sodium
formate in synthesis solution was studied
on the membrane characterization and performance.
The team evaluated the performance
of ZIF-8 membranes in desalination,
using FO. " To the best of our knowledge, no
studies have reported on ZIF-8 membranes
for desalination using forward osmosis, "
says the team.
The team found ZIF-8 to be a promising
membrane material for desalination using FO.
However, it said, improvements in membrane
morphology to prepare a well-intergrown,
continuous and thin membrane are needed
to enhance its performance in terms of water
flux, reverse-solute flux and salt rejection.
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
APRIL 2019
Edited by:
Gerald Ondrey
'GREEN' STEELMAKING
Seamlessly following
the
successful completion of the
GrInHy project (Green Industrial
Hydrogen via reversible
high-temperature electrolysis)
in February, the GrInHy2.0
project was launched last
month at the Salzgitter Flachstahl
GmbH steelworks
(Germany; www.salzgitterflachstahl.de).
Together
with partners Sunfire GmbH
(Dresden, Germany; sunfire.
de), Paul Wurth S.A., Tenova
S.p.A., French research center
CEA and Salzgitter Mannesmann
Forschung GmbH,
the world's most powerful
high-temperature electrolyzer
(HTE) is being constructed for
the energy-efficient production
of H2. The GrInHy2.0
project has an overall budget
of € 5.5 million.
GrInHy2.0 marks the first implementation
of an HTE with
a power rating of 720 kW in
an industrial environment. By
the end of 2022 it is expected
to have been in operation for
at least 13,000 h, producing
a total of around 100 metric
tons of high-purity (99.98 %)
H2, which will be used for annealing
processes in the integrated
steelworks as a replacement
for H2 produced
from natural gas.
H2 as a reducing agent is
also a central element in
SALCOS (Salzgitter LowCO2
Steelmaking), the Salzgitter
Group's concept for
reduced-CO2 steel production,
is set to replace the
carbon previously required
to reduce iron ore to metallic
iron. SALCOS is based on
elements of various proven
technologies,
allowing
the
concept to be implemented
swiftly at an industrial level.
By increasing the scale of the
HTE, the GrInHy2.0 project
will have the ability to extensively
trial and test the integration
of " green " H2 into the
steelworks processes. To do
so, the gaseous product of the
(Continues on p. 8)
7
http://www.glatt.com http://www.salzgitter http://www.flachstahl.de http://www.utm.my http://WWW.CHEMENGONLINE.COM
Chemical Engineering April 2019

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