Carbon Capture (Utilization) Storage

Carbon capture and storage (CCS) refers to a collection of technologies that can combat climate change by reducing carbon dioxide (CO2)?emissions. The idea behind CCS is to capture the CO2?generated by burning fossil fuels before it is released to the atmosphere.

The question is then: What to do with the captured CO2? Most current CCS strategies call for the injection of CO2?deep underground. This forms a “closed loop”, where the carbon is extracted from the Earth as fossil fuels and then is returned to the Earth as CO2.

CCS is sometimes referred to as CCUS, where the “U” stands for utilization. Enhanced oil recovery (EOR) is the major use of CO2?today.

EOR is where CO2?is injected into active oil reservoirs in order to recover more oil. Other possible uses of CO2?include making chemicals or fuels, but they require large amounts of carbon-free energy, making the costs too high to be competitive today. For large-scale implementation of CCS, utilization is projected to use less than 10% of the captured CO2.

CO2?could also be made into useful products.?Companies and labs are working on turning CO2?into plastics, building materials like?cement and concrete, fuels, futuristic materials like carbon fibers and graphene, and even household products like baking soda, bleach, antifreeze, inks and paints. Some of these products are already being sold, but none in very large amounts.

Or we could use the CO2?to grow algae or bacteria.?This can then be the basis for making?biofuels,?fertilizers, or animal feed.

Capturing CO2 from the air

There has also been considerable interest recently in using CCS technologies to remove CO2 from the atmosphere.? One option is bioenergy with CCS (BECCS), where biomass (like wood or grasses) removes CO2 from the air through photosynthesis. The biomass is then harvested and burned in a power plant to produce energy, with the CO2 being captured and stored. This creates what is called “negative emissions” because it takes CO2 from the atmosphere and stores it.? Another negative emission option is called direct air capture (DAC), where CO2 is removed from the air using a chemical process.? However, the concentration of CO2 in the air is about 300 times less than in the smokestacks of power plants or industrial plants, making it much less efficient to capture. Because of this, DAC is quite expensive today.

Capturing CO2 from the Flue Gas

Amines capture carbon from flue gas through a process called post-combustion capture, which involves the following steps:

1. Absorption: Flue gas is fed into an absorber column where it comes into contact with an amine-based liquid absorbent. The amine absorbs and attaches to the carbon dioxide (CO2) in the flue gas.
2. Desorption: The amine-rich solvent is then fed into a desorber column where the CO2 is heated and released.
3. Storage or use: The captured CO2 can be stored or used for other purposes.
4. Regeneration: The regenerated solvent is cooled and returned to the absorption column

Capture of CO2 from flue gas of coal based power plant and its conversion to methanol is a priority area for NTPC. This CO2 to Methanol conversion plant shall be a unique plant, globally, where CO2 shall be drawn from waste flue gas of a coal fired power plant and shall be converted to methanol thru a catalytic hydrogenation process. It will also create a potential new business avenues and revenue stream for NTPC

?With one project already commissioned in NTPC, Vindhyachal by Jakson green ; NTPC is geared to deploy the same at all of their Thermal Power Stations.

https://www.pv-magazine-india.com/2023/04/05/jakson-green-to-build-co2-to-methanol-plant-in-partnership-with-ntpc/