Accelerating Net Zero
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ACCELERATING NET ZERO
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ACCELERATING NET ZERO
hydrate based process. Currently, a large 30 litres demonstration of this
process is operational at IITM which has demonstrated a modular design
for separation of CO2 from a rich gas mixture with reasonable kinetics
which operates in continuous mode like a PSA approach. Talking about
PSA, IITM has done extensive work on carbon dioxide capture using
MoF/ZIF, activated carbon-based adsorbents, Zeolite materials etc. for
adsorption of CO2 rich and CO2 lean gas mixtures. Further, solid materials
which chemically binds to CO2 has also been studied in detail for direct air
capture application. An end to end solution for direct air capture has been
demonstrated and an operational pilot plan exist in the campus.
As discussed above, captured carbon dioxide needs to be either
utilized or sequestrated. CO2 utilization is a very rich research field,
and IITM has developed quiet a number of such processes where at
laboratory scale CO2 to methanol, formic acid, methane and other higher
hydrocarbon through carbon -carbon coupling has been demonstrated.
CO2 utilization processes have difficulty in scale-up and IITM is looking
forward to demonstrate such processes at large scale, however, this
is still on going. However, a significant work on fundamental science
and demonstration of CO2 sequestration demonstrations have been
done at IITM. Carbon dioxide sequestration is defined as storage of
anthropogenic CO2 in geological formations either permanently or for
geologically significant time periods. Depleted oil and gas reservoirs,
saline aquifers, unmineable coal beds and deep-sea beds are geological
formations that can be used for long-term CO2 sequestration. India has a
complex and diverse geology. Much of the geology of present-day India is
a result of volcanic eruptions dating back to prehistoric eras. The Indian
subcontinent is mantled with the remnants of at least five continental
flood basalt provinces that occurred between the middle Proterozoic to
the late Cretaceous-early Tertiary eras. The geographical land area of
India can be divided into three parts: The Deccan Trap (youngest of the
five continental flood basalt provinces), Gondwana and Vindhayan. The
Deccan Trap is acknowledged to be one of the largest volcanic features
on Earth. It presently occupies around half a million square kilometers
of western and central India and southernmost. Such sediments are
also prominently found under the sea-bed and could be a rich source of
CO2 sequestration. An alternative solution exist in the form of injecting
CO2 in either gaseous or liquid form 100-500 m beneath the seabed and
sequester it in the form of clathrate hydrates within the bounds of
the gas hydrate stability zone (GHSZ). CO2 storage in the form of solid
hydrates under the sea-bed is promising, as 1 m3 of CO2 hydrate can store
120–160 m3 of CO2 gas at STP. Studies like, effects of water salinity and
clay on CO2 hydrate formation to comprehend the effect of electrolyte and
capillary effects on the interlayer pores have been studied in laboratory
scale at IIT Madras. These studies have also helped in determining
the appropriate CO2 injection depth for hydrate formation in such
unconsolidated sediments in the deep sea. Further, IITM researchers
have investigated different kinetic promoters with porous silica gel, silica
sand, pumice stone etc. to concluded that certain additives could improve
the efficiency of such sequestration by influencing the induction time and
in improving the degree of hydrate formation. A pilot scale demonstrator
for CO2 sequestration was developed at IIT Madras which is equipped
with mild fracking setup, injection wells (both vertical and horizontal)
for liquid/gaseous CO2 injections. This unit not only the measures the
rate and quantity of CO2 sequestrated at conditions similar to sub-
sea environment, it also could study the stability of sequestered CO2.
Multiple options for efficient CO2 sequestration was demonstrated and It
was also identified that the sequestered CO2 could be stable upto 10-12 oC
rise in sub-sea temperature.
FIGURE 1. Demonstration of a multi-bed reactor for CO2 capture using Gas-Hydrates Formation and Dissociation Cycle
FIGURE 2. Demonstration of point source CO2 capture in a mobile container unit
The Deccan Trap
(youngest of the five
continental flood
basalt provinces),
Gondwana and
Vindhayan. The
Deccan Trap is
acknowledged to be
one of the largest
volcanic features on
Earth. It presently
occupies around
half a million square
kilometers of western
and central India and
southernmost
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