**1. Introduction**

Carbon dioxide capture, utilization and storage (CCUS) technologies involve capturing carbon dioxide (CO2 ) emissions to create a synergy between the high demand for fossil fuel and mitigating greenhouse gas effects at the lowest possible cost.

CCUS captures over 90% of CO2 emissions from power plants and industrial facilities and is predicted to reduce global gas emissions by 14% in 2050. Bearing in mind that, fossil fuelfired power plants in the United States account for 30% of U.S. total greenhouse gas (GHG) emissions, which will only continue to increase regardless [1]. The capacity of CO2 utilization

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

and storage in the U.S. is approximately 30 billion metric tons, equivalent to 35 years of CO<sup>2</sup> emissions captured from 140 Gigawatts (GWs) of coal-fired power [2, 3].

• Natural sources of CO<sup>2</sup>

gases with 90% CO2

5 Mt/a of CO2

final phase [8].

and concentrate CO2

burn the H2

capture [7].

turbine [1, 6].

• Pre-combustion carbon capture

• Post-combustion carbon capture

shift reaction, while a solvent separates the CO2

It involves the use of chemical solvents to separate CO2

ide (CO) and hydrogen (H2

• Oxyfuel carbon capture

exhaust gas for capture [7].

**2.1. Carbon capture benchmarks**

mately 65 Mt/a of CO<sup>2</sup>

[8].

in 2000 to a projected 20 Mt/a of CO2

using the following processes [7]:

lenges of natural-gas processing include: higher oxygen (O2

tion, higher flue gas and high flame temperatures [1].

into several (high-value) products to capture CO2

are made up of underground accumulations of naturally occurring

Carbon Dioxide Utilization and Sequestration in Kerogen Nanopores

in 2015 [8]. Some of the known chal-

http://dx.doi.org/10.5772/intechopen.78235

concentra-

59

through a later


from Biofuels (eth-

is captured per year [1, 3].

) content, lower CO2

as a by-product. This process is projected

. The pre-combustion carbon capture

from the resulting flue gas from fos-

. As of 2015, the natural sources are projected to account for approxi-

• Natural-gas processing are also naturally occurring underground accumulations but with significant methane content. The contribution of natural-gas processing has increased from

• Hydrocarbon conversion involves the conversion of crude oil (or hydrocarbon feedstock)

However, with the recent inclusion of power generation, new systems are designed to capture

Fuel undergoes gasification instead of combustion to produce syngas made of carbon monox-

is mostly combined with an integrated gasification combined cycle (IGCC) power plant to

sil fuel combustion. This method is commonly used by modified power plants for carbon

In 2016, the US Energy Information Administration (EIA) reported that electricity generated from natural gas is expected to exceed that of coal for the first time [9]. This calls for more

There are about 21 commercial-scale carbon capture projects around the world with 22 more in development [7]. Below is a list of a few of the many benchmarks in carbon capture:

anol) production, and stores in the Mt. Simon Sandstone, a deep saline formation, Decatur,

This process requires the combustion of fossil fuel in pure oxygen to render the CO2

effective measures to be put in place to curtail greenhouse gas (GHG) effects.

• As of 2017, the Archer Daniels Midland (ADM) Company captures CO<sup>2</sup>

IL. An estimated amount of 1.1 million tons of CO<sup>2</sup>

). Carbon monoxide (CO) is then converted to CO2

from H2

in a combustion turbine and the resulting exhaust heat, used to power a steam

to increase to approximately 5 Mt/a based on known projects under construction and in

The captured CO2 emissions are usually injected into geologic formations such as deep saline aquifers for storage, but most recently associated with enhanced oil recovery (CO2 -EOR) in oil and gas reservoirs. Although, CO<sup>2</sup> -EOR has been practiced for decades now, recent advances combine the recovery process with CO2 sequestration.

CO2 -EOR involves the injection of CO2 into an oil/gas reservoir to recover more hydrocarbons (oil and/ or gas). Mostly, the volume of the injected CO2 differs from that of the produced fluid with CO2 , indicating trapping or storage. Hence, incorporating the storage of anthropogenic CO2 into CO2 -EOR in already developed oil and gas reservoirs seems economically and technically feasible. Different forms of trapping mechanisms, such as hydrodynamic and capillary trapping hold the CO2 in place to prevent movement/leakage, ubiquitous to almost all oil and gas reservoirs [2, 3].

The United States (US) leads the world in both the number of CO2 -EOR projects and in the volume of CO2 -EOR oil production due to complimentary geology (low thermal gradient and high permeability) in the Permian Basin, located in West Texas and southeastern New Mexico [4]. Approximately 11 trillion cubic feet (560 million metric tons) total volume of CO<sup>2</sup> is utilized in by US CO2 -EOR as compared to 100 trillion cubic feet (5090 million metric tons) per year of total US CO2 emissions from industrial sources [1, 4–6].

Although, CO<sup>2</sup> storage during CO2 -EOR in conventional oil and gas reservoirs is proven effective, the potential to sequester in unconventional organic-rich shales (gas/oil) is even more promising and economical, yet there has been minimum attention given to these vast resources. Organic-rich shales are naturally suited for CO2 storage due to the ultra-tight impermeable nature of the formation, which would curtail CO2 leakage. Moreover, the adsorptive surface of kerogen and kerogen nanopores in shales can store substantial amounts of CO2 in its adsorbed state [5–7]. Thus, in depleted shale gas reservoirs, injected CO2 replaces methane (CH4 ) in the kerogen micro and nanopores and adsorb to the kerogen surface for storage [7–9]. This chapter therefore investigates the potential of CO2 sequestration in kerogen nanopores.
