Another way to lower the CO2 emission level: Post-combustion capture

What exactly is post-combustion capture?

            According to Herzog, “this refers to the capture of CO2 prior to combustion. This is not an option at the pulverized coal (PC) power plants that comprise most of the existing capacity. However, it is an option for integrated coal gasification combined cycle (IGCC) plants. In these plants, coal is first gasified to form synthesis gas (syngas, a mixture whose key components are carbon monoxide and hydrogen). The syngas then undergoes the water-gas shift, in which the CO reacts with steam to form CO2 and additional H2. The CO2 is then removed, and the hydrogen is diluted with nitrogen and fed into a gas turbine combined cycle. The advantage of this approach is that it is much less expensive than the post-combustion capture process. The disadvantages are that there are only a few IGCC plants in the existing coal fleet and IGCC plants are more expensive than PC plants when costs of CO2 capture are not included.”

            There are pros and cons with post-combustion capture.

Pros:

1.     it’s easy to spread to industrial and power plant stations with renovations(UK 400 MW retrofit by 2014)

2.     it has already existed for more than 60 years

3.     it’s adaptable to current fossil fuel plants

4.     Cryogenic capture reduces cost by 40% in experimental plants

Cons:

1.     it’s a high cost program for dealing with the solvents, generating the machine and also using a lot of water, leading to other problems with the replacement

2.     this technology has not been widely used and lacking of experience on large scale

3.     it has large footprint

Reference: Herzog, Howard, Jerry Meldon, and Alan Hatton. "Advanced Post-Combustion CO2 Capture." Clean Air Task Force. (2009): 3-38. Print.