Carbon Capture and storage technologies around the world

1. Carbon capture and storage (CCS)
CCS is a process in which a relatively pure stream of carbon dioxide (CO2) from industrial sources is
separated, treated and transported to a long-term storage location. For example, the burning of fossil
fuels or biomass results in a stream of CO2 that could be captured and stored by CCS. Usually the CO2
is captured from large point sources, such as a chemical plant or a bioenergy plant, and then stored in
a suitable geological formation. The aim is to reduce greenhouse gas emissions and thus mitigate
climate change. For example, CCS retrofits for existing power plants can be one of the ways to limit
emissions from the electricity sector and meet the Paris Agreement goals.
Carbon dioxide can be captured directly from the gaseous emissions of an industrial source, for
example from a cement factory (cement kiln). Several technologies are in use: adsorption, chemical
looping, membrane gas separation or gas hydration.
Storage of the captured CO2 is either in deep geological formations or in the form of mineral
carbonates. Geological formations are currently the favored option for storage. Pyrogenic carbon
capture and storage (PyCCS) is another option. Long-term predictions about submarine or
underground storage security are difficult. CCS is so far still a relatively expensive process. Carbon
capture becomes more economically viable when the carbon price is high, which is the case in much
of Europe. Another option is to combine CCS with a utilization process where the captured CO2 is
used to produce high-value chemicals to offset the high costs of capture operations.

3. Globally, a number of laws and rules have been issued that either support or mandate the
implementation of CCS. In the US, the 2021 Infrastructure Investment and Jobs Act provides
support for a variety of CCS projects, and the Inflation Reduction Act of 2022 updates tax credit law
to encourage the use of CCS. Other countries are also developing programs to support CCS
technologies, including Canada, Denmark, China, and the UK.
• Global proposed (grey bars) vs. implemented
(blue bars) annual CO2 captured. Both are in
million tons of CO2 per annum (Mtpa). More
than 75% of proposed CCS installations for
natural-gas processing have been implemented.

5. Carbon Capture in Action
As of 2020, at least 26 commercial-scale carbon capture projects are operating around the world with 21 more in
early development and 13 in advanced development reaching front end engineering design (FEED). Industrial
processes where large-scale carbon capture has been demonstrated and is in commercial operation include coal
gasification, ethanol production, fertilizer production, natural gas processing, refinery hydrogen production and,
most recently, coal-fired power generation.
• Carbon Capture Milestones
• 2003: Core Energy/South Chester Gas Processing Plant in Michigan. Carbon
dioxide is captured by Core Energy from natural gas processing for EOR in northern
Michigan with over 2 million MT captured to date.
• 2008: Snøhvit Carbon Dioxide Storage offshore of Norway. Carbon dioxide is
captured from an LNG facility on an island in the Barents Sea. The captured carbon
dioxide is stored in an offshore subsurface reservoir. To date, more than 4 million
tons of carbon dioxide have been stored.
• 2009: Chaparral/Conestoga Energy Partners’ Arkalon Bioethanol plant in Kansas.
The first ethanol plant to deploy carbon capture, it supplies 170,000 tons of carbon
dioxide per year to Chaparral Energy, which uses it for EOR in Texas oil fields.
• 2010: Occidental Petroleum’s Century Plant in Texas. The carbon dioxide stream
from this natural gas processing facility is compressed and transported for use in
the Permian Basin.
• 2012: Air Products Port Arthur Steam Methane Reformer Project in Texas. Two
hydrogen production units at this refinery produce a million tons of carbon dioxide
annually for use in Texas oilfields.
• 2012: Conestoga Energy Partners/PetroSantander Bonanza Bioethanol plant in
Kansas. This ethanol plant captures and supplies roughly 100,000 tons of carbon
dioxide per year to a Kansas EOR field.
• Carbon Capture Milestones
• 1972: Terrell gas processing plant in Texas. A natural gas processing
facility (along with several others) began supplying carbon dioxide in
West Texas through the first large-scale, long-distance carbon dioxide
pipeline to an oilfield.
• 1982: Koch Nitrogen Company Enid Fertilizer plant in Oklahoma. This
fertilizer production plant supplies carbon dioxide to oil fields in
southern Oklahoma.
• 1986: Exxon Shute Creek Gas Processing Facility in Wyoming. This
natural gas processing plant serves ExxonMobil, Chevron, and Anadarko
Petroleum carbon dioxide pipeline systems to oil fields in Wyoming and
Colorado and is the largest commercial carbon capture facility in the
world at 7 million tons of capacity annually.
• 1996: Sleipner Carbon Dioxide Storage Facility offshore of Norway.
This project captures carbon dioxide from gas development for storage
in an offshore sandstone reservoir. It was the world’s first geologic
storage project. Roughly 0.85 million tonnes of CO2 is injected annually
for a cumulative total of over 16.5 million tonnes as of January 2017.
• 2000: Dakota Gasification’s Great Plains Synfuels Plant in North
Dakota. This coal gasification plant produces synthetic natural gas,
fertilizer, and other byproducts. It has supplied over 30 million tons of
carbon dioxide to Cenovus and Apache-operated EOR fields in southern
Saskatchewan as of 2015.

6. Carbon Capture Milestones
• 2016: Abu Dhabi CCS Project Phase 1: Emirates Steel Industries. Carbon capture
technology was deployed for the first time on an operating iron and steel plant.
The captured carbon dioxide is used for enhanced oil recovery by the Abu Dhabi
National Oil Company.
• 2017: NRG Petra Nova project in Texas. NRG completed on time and on budget a
project to capture 90 percent of the carbon dioxide from a 240 MW slipstream of
flue gas of its existing WA Parish plant, or roughly 1.6 million tons of carbon
dioxide per year. The carbon dioxide is transported to an oil field nearby.
• 2017: ADM Illinois Industrial Carbon Capture & Storage Project. Archer Daniels
Midland began capturing carbon dioxide from an ethanol production facility and
sequestering it in a nearby deep saline formation. The project can capture up to
1.1 million tons of carbon dioxide per year.
• 2020: Boundary Dam 3 facility in Saskatchewan, Canada surpassed over 4 million
tons of CO2 captured and stored.
• 2020: Shell Quest project in Alberta, Canada which captures CO2 from a hydrogen
production unit at the Scotford refinery surpassed 5 million tons of CO2 stored.
• 2020: NRG Petra Nova Project in Texas was idled due to the collapse of West Texas
crude oil prices early in the COVID-19 pandemic.
• 2020: Hydrogen to Humber Saltend (H2H Saltend) project in the UK. Norwegian
energy company Equinor announced a project to produce zero-emission hydrogen
from natural gas in combination with carbon capture and storage technology to
provide clean energy to the Humber region, the UK’S largest industrial cluster.
• 2013: ConocoPhillips Lost Cabin plant in Wyoming. The carbon dioxide
stream from this natural gas processing facility is compressed and
transported to the Bell Creek oil field in Montana via Denbury
Resources’ Greencore pipeline.
• 2013: Chaparral/CVR Energy Coffeyville Gasification Plant in Kansas.
The carbon dioxide stream (approximately 850,000 tons per year) from
a nitrogen fertilizer production process based on gasification of
petroleum coke is captured, compressed and transported to a
Chaparral-operated oil field in northeastern Oklahoma.
• 2013: Antrim Gas Plant in Michigan. Carbon dioxide from a gas
processing plant owned by DTE Energy is captured at a rate of
approximately 1,000 tons per day and injected into a nearby oil field
operated by Core Energy in the Northern Reef Trend of the Michigan
Basin.
• 2013: Petrobras Santos Basin Pre-Salt Oil Field CCS offshore of Brazil.
This project involves capturing carbon dioxide from natural gas
processing for use in enhanced oil recovery in the Lula and Sapinhoá oil
fields.
• 2014: SaskPower Boundary Dam project in Saskatchewan, Canada.
SaskPower completed the first commercial-scale retrofit of an existing
coal-fired power plant with carbon capture technology, selling carbon
dioxide locally for EOR in Saskatchewan.
• 2015: Shell Quest project in Alberta, Canada. Shell began operations
on a bitumen upgrader complex that captures approximately one
million tons of carbon dioxide annually from hydrogen production units
and injects it into a deep saline formation.
• 2015: Uthmaniyah CO2-EOR Demonstration in Saudi Arabia. This
project captures carbon dioxide from the Hawiyah natural gas liquids
recovery plant. The captured carbon dioxide is used for enhanced oil
recovery in the Ghawar oil field.

7. CO2 capture systems
There are four basic systems
for capturing CO2 from use of
fossil fuels and/or biomass:
• Capture from industrial
process streams.
• Post-combustion capture.
• Oxy-fuel combustion
capture.
• Pre-combustion capture.

8. • Pre-Combustion Carbon Capture: Fuel is gasified (rather than combusted) to produce
a synthesis gas, or syngas, consisting mainly of carbon monoxide (CO) and hydrogen
(H2). A subsequent shift reaction converts the CO to CO2, and then a physical solvent
typically separates the CO2from H2. For power generation, pre-combustion carbon
capture can be combined with an integrated gasification combined cycle (IGCC)
power plant that burns the H2 in a combustion turbine and uses the exhaust heat to
power a steam turbine.
• Post-Combustion Carbon Capture: Post-combustion capture typically uses chemical
solvents to separate carbon dioxide out of the flue gas from fossil fuel combustion.
Retrofits of existing power plants for carbon capture are likely to use this method.
• Oxyfuel Carbon Capture: Oxyfuel capture requires fossil fuel combustion in pure
oxygen (rather than air) so that the exhaust gas is carbon-dioxide-rich, which
facilitates capture.

9. Types of CO2 capture technologies
The major technologies proposed
for carbon capture are:
• Membrane
• Oxyfuel combustion
• Absorption
• Multiphase absorption
• Adsorption
• Chemical looping combustion
• Calcium looping
• Cryogenic
• Direct air capture (DAC)
General schemes of the main
separation processes relevant for CO2
capture. The gas removed in the
separation may be CO2, H2 or O2.
In Figures B and C one of the
separated gas streams (A and B) is a
concentrated stream of CO2, H2 or O2
and the other is a gas stream with all
the remaining gases in the original gas
(A+B).

10. Common solvents used for
the removal of CO2 from
natural gas or shifted syngas
in pre-combustion capture
processes.

11. • CAPTURE TECHNOLOGIES FOR POWER PLANTS
The CO2 (molar concentration) levels of flue gas from fuel combustion in power plants are typically only approximately 15%–20%. Various “capture technologies” use
different strategies to concentrate the CO2 to levels of approximately 75%–80% or more making subsequent CO2 compression to the supercritical state viable for geological
storage. Recent R&D on CO2 capture from power stations has focused on three technologies that have all progressed through pilot-scale and semicommercial scale (Stanger
and Wall, 2007), which are:-
1. CO2 capture from conventional pulverized fuel (PF) technology with scrubbing of the flue gas for CO2 removal termed post combustion capture (PCC), which uses the
same technology used to remove CO2 from natural gas in the oil and gas industry. A flow sheet is given in below Figures.
2. Integrated gasification combined cycle (IGCC) with a shift reactor to convert CO to CO2, followed by CO2 capture, which is called precombustion capture (below Figures).
3. Oxyfuel utilizes oxygen rather than air for combustion, where the oxygen is diluted with an external recycled flue gas to reduce its combustion temperature and add
volume to carry the combustion energy through the heat transfer operations (below Figures).
PCC and oxyfuel can be retrofitted to an existing plant, whereas IGCC requires a new build. PCC and IGCC can utilize partial capture from flue gas. IGCC may use O2 rather
than air as the oxidant to establish higher proportions of CO2, but only oxyfuel does not require CO2 capture prior to compression. All plants use similar combustion
temperatures of 1300–1700°C, but IGCC with CO2 capture uniquely also requires high pressures of approximately 7–8 MPa. All three (first-generation) technologies are
associated with higher generation costs with energy penalties of approximately 25%. Important contributors to efficiency losses are PCC—solvent regeneration and CO2
compression, IGCC—oxygen production and CO2 compression, and oxyfuel—oxygen production and CO2 compression. Second generation technologies target
lowering the energy penalty but are currently only at pilot scale.
PCC technology, with new
unit operations required for a
retrofit of an existing PF
power station, with gas
cleaning, solvent scrubbing,
and compression.

12. IGCC technology adapted
for capture, to include a shift
reactor, and CO2
compression
Oxyfuel technology, to
include an air separation
unit (ASU) for oxygen
supply, recycled flue gas
(RFG) and CO2 purification
and compression.

13. Technologies and methods that are utilized regularly in CO2 separation. In post-
combustion carbon capture technologies, there are many four routes: absorption,
adsorption, membrane separation and microalgae.

14. Post-combustion capture systems:-
As example in below Figure shows a general schematic of a coal-fired power plant in which additional unit operations are
deployed to remove the air pollutants prior to CO2 capture in an absorption-based process.

15. Absorption processes in post-combustion capture make use of the reversible nature of the chemical reaction of an
aqueous alkaline solvent, usually an amine, with an acid or sour gas. The process flow diagram of a commercial
absorption system is presented in below Figure.

16. Pre-combustion technology consists of an air separation unit for oxygen separation (not mandatory). Then the fuel is reacting with air
or O2 to produce mainly synthesis gas, which is then sent to the shift reactor unit to produce hydrogen and CO2. The produced
hydrogen can be used to fuel electric cars or to produce electricity through a gas turbine, while the fuel gas is sent to the heat recovery
and steam generation unit for electricity production. Finally, the CO2 is compressed and dehydrated for transport and storage
purposes are required when oil or coal is utilized to eliminate impurities, ash and Sulphur-containing compounds. In the first
generation of the integrated gasification combined cycle (IGCC), the main cause for efficiency loss was the WGSR step, which was
responsible for 44% of the total efficiency loss. This was due to the energy required for steam generation along with the heat released
within the WGSR process as it is an equilibrium limited and exothermic process.

17. Oxyfuel combustion
Oxyfuel combustion technology consists of an air separation unit for oxygen separation (mandatory). Then the carbon-based
fuel is combusted in the re-circulated fue gas and pure oxygen (O2) stream in a boiler. Then the fuel gas is sent to the particle
removal unit, followed by the cooler and condenser unit to remove water and then to the sulphur removal unit before
sending it again to the cooler and condenser unit. Finally, the CO2 is compressed and dehydrated for transport and storage.

18. Post-combustion
Post-combustion technology,
where the hot fuel gas is
cooled first and then sent to a
CO2-absorber unit that
usually contains mono
ethanol amine solvent as
traditional sorbent. Then the
CO2-rich absorbent is sent to
the CO2-stripper unit to
release the CO2 gas, while the
CO2-lean absorbent is sent
back to the CO2-absorber
unit.
Finally, pure CO2 is comp-
ressed and dehydrated for
transport in pipelines and
stor-age purposes.

19. Industrial process capture systems
• Natural gas sweetening
Depending on the level of CO2 in natural gas, different processes for natural gas sweetening (i.e., H2S and CO2 removal) are
available (Kohl and Nielsen, 1997 and Maddox and Morgan, 1998):
• Chemical solvents
• Physical solvents
• Membranes
• Steel production
The iron and steel industry is the largest energy-consuming manufacturing sector in the world, accounting for 10-15% of total
industrial energy consumption (IEA GHG, 2000a). Associated CO2 emissions were estimated at 1442 MtCO2 in1995.
CO2 recovery from blast furnace gas and recycle of CO-rich top gas to the furnace. A minimum quantity of coke is still required
and the blast furnace is fed with a mixture of pure O2 and recycled top gas. The furnace is, in effect, converted from air fring to
oxy-fuel fring with CO2 capture. This would recover 70% of the CO2 currently emitted from an integrated steel plant (Dongke et
al., 1988). It would be feasible to retroft existing blast furnaces with this process.
• Ammonia production
CO2 is a byproduct of ammonia (NH3) production. A typical modern plant will use the amine solvent process to treat 200,000
Nm3 h-1 of gas from the reformer, to produce 72 tonnes h-1 of concentrated CO2 (Apple, 1997). The amount of CO2 produced in
modern plants from natural gas is about 1.27tCO 2/tNH3.

20. Storage Capacity
For ease of transport and greater storage capacity, CO2 is best injected as a dense supercritical fluid. The critical
point where CO2 has the density typical of a liquid and the viscosity of a gas is at 31.1°C and 7.38 MPa (Figure 23.5).
Based on average geothermal and hydrostatic pressure conditions, this equates to an approximate minimum
subsurface depth of 600–800 m.
Below this depth (under normal sedimentary basin conditions), supercritical CO2 is 30%–40% less dense than a
typical saline formation water under the same conditions. This means that the lighter CO2 will naturally rise by
buoyancy through the reservoir until trapped by various physical or geochemical trapping mechanisms. The pore
volume available for storage (GCO2) can be calculated using
GCO2= A × h × φ × ρ × E
where
• A is the area of storage site
• h is the storage formation thickness
• ϕ is the rock porosity (% of voids per bulk rock volume)
• ρ is the density of CO2
• E is the storage efficiency

21. Schematic diagram
summarizing potential
subsurface impacts as a
result of CO2 injection.
(After Michael, K. et al.
2016. Environmental
Science: Processes &
Impacts. 18: 164–175.)

22. The bibliometric
mapping of
technologies used
in the carbon
capture and
storage route:
network
visualization of
most of the
prominent
keywords in
literature in the
period of 2010–
2020,

23. One of the most promising approaches in CCUS route is
CO2 capture using physical adsorption where the sorbent
is in the
form of a metal oxide (MeO, where Me denotes the metal
species), such as calcium oxide (CaO).
After CO2 adsorption, the metal adsorbent becomes a
metal carbonate in the form of MeCO3, where the later
reacts with
renewable hydrogen derived from water electrolysis, and
the source of electricity is renewable; either from solar or
wind energies. The interaction between the metal
carbonate and the renewable hydrogen will lead to the
formation of methane, which is the main constituent in
natural gas, that consequently can be compressed and
used as a recycled fuel in power plants (Sun et al. 2021; Lux
et al. 2018).
When combusting natural gas (methane), it releases a large
amount of heat along with lower emissions compared to
other hydrocarbons (Osman et al. 2018b). Thus, this CCUS
approach, when integrated with biomass utilization as a
solid fuel, could eventually lead to a negative carbon
emission system if the CO2 is stored or utilized in
applications such as construction, where the possibility of
CO2 entering the atmosphere once more is eliminated.
The loop process where the fuel gas derived from power plants or any other source of
CO2 is then combined with renewable hydrogen gas over adsorbent materials to
produce methane as recycled fuel. The hydrogen fuel could be obtained from water
hydrolysis, where the source of electricity is either from solar or wind energy sources.
The recycled methane (main consistent in natural gas) is then dried and compressed
before further utilisation in the process.

24. Conclusion
Despite the speed of maturity in renewable technologies, we still rely on fossil-based fuels to generate the energy demand
needed globally. While waiting for renewable energy technologies to mature enough and replace fossil-based fuel, carbon
capture storage and utilization of fossil-based emissions are crucial as a transition state. Herein, we reviewed the three main
routes of carbon capture, storage and utilization: pre-combustion, post-combustion and oxy-fuel combustion routes along with
the carbon storage and utilization technologies.
Pre-combustion technology is promising in carbon capture, while there are many challenges to improving its overall efficiency.
For instance, the solvent regeneration temperature needs to be conducted at a lower temperature than currently used to
avoid any reduction in the solvent. In the oxy-fuel combustion route, investigating new novel routes of air separation is quite
important herein, such as ion-transport and oxygen-transport membranes along with chemical looping methods. Traditional
and novel technologies that are used in carbon capture have been evaluated such as post combustion (traditional) and partial
oxy-combustion (novel).
In the post-combustion technology, there are desirable properties in novel solvents such as the high cyclic capacities, low
production cost, low corrosiveness, lower degradation and thus lower by-products along with the environmental
impact. At the same time, there are many challenges associated with membrane separation, such as water condensation on
the membrane, rapid diminution of selectivity and permeance after operation along with emissions (NOx and SOx) that pass
through the membrane. Although the precombustion technology offers higher efficiency than that of post-combustion
technology, it is more expensive. To reduce the cost associated with the pre-combustion route, finding a superior absorption
solvent is crucial.
Currently, post-combustion technology is the most mature and widely used route among the three main routes of carbon
capture and storage. Valorization of the captured CO2 was divided into two main categories;
(1) conversion into fuels or chemicals
(2) physical utilization of CO2.
It may be used directly in other uses, in addition to carbonated beverages (i.e. free extinguisher, refrigerant and welding
medium). Direct applications of CO2 are limited in scope and have a minor impact on the overall reduction of CO2 emissions.
Additionally, indirect utilization of CO2 in large scale industries is conceived to improve the performance of different
processes.