CCS Flashcards
What is carbon capture and storage?
CO2 can be captured from a process or the atmosphere and permanently stored geologically
Why is CCS important?
fossil fuels will remain a major source of energy globally
What are the 3 categories of carbon capture systems?
Post-combustion capture
pre-combsution capture
oxt fuel combustion
What is post-combustion capture?
Separate CO2 from gas mixture after combustion
What is pre-combustion capture?
Sperate CO2 from the production of H”, combust the H2
What is oxy-fuel combustion?
Combust fuel in O2, no further spearation needed
What is the parasitic energy for post-combustion capture?
~20%
What are the benefits of post-combstion capture?
retrofitable
Is it cheaper to retrofit or build post-combustion capture with the power plant?
Build with power plant
£570MM new
£700MM retrofit
What are the advantages of post-combsustion capture?
- retrofittable
- mature technology
- experience with ‘large-scale’ in the oil and gas indsutry
- flexible
What are the disadvantages of post-combustion capture?
- high CapEx - large gas volumes - large equipment
- parasitic energy
- solvent disposal
How does pre-combustion CO2 capture work?
react fuel with steam and small amount of O2, produces syngas
- reduce syngas to get CO2 and H2
- H2 used as a fuel
How does post-combustion capture work?
- lean solvent is contacted with the CO2 laden gas
- heat is applied to the rich solvent to reverse the reaction
- take steam away from plants
What are the advantages of pre-combustion capture?
- uses processes that are already commercially used
- lower energy penalty than post-comustion capture
- can be very efficient
What are the disadvantgaes of pre-combustion capture?
- high CapEx
- complex - low flexibility
- no commercial scale demonstration
How does oxy fuel combustion work?
- O2 separated from air
- mixture of O2 and CO2 used to combust fuel
- no further separation required
what kind of air seperation methods are there?
Cryogenic distilation
(very hgih capacity, very high purity, high energy requirements)
vacuum swing adsorption
(medium capcaity, high purity, low energy requirements)
Membranes (high purity, very low capacity
How is CO2 transported?
Large scale:
pipeline, ship
Small scale, trucks rail
under pressure (100 bar 30C) liqufied (37C 11 bar)
either way significatn energy requirement
In a pipeline what do we have to consider?
The number of sources
the distance
the number of sinks
How do we store Co2?
We can inject it into the ground
How long does CO2 stored in the ground remain there for?
over 10,000 years
What is the current CO2 storage research focusing on?
site characterisation
plume mitigation
managing risks of leaking
detecting leaks with certainty
How much more expensive than other technologies is CCS?
Substantially - cost will go down if adopted though
what is direct air capture DACCS?
When CO2 is adsorped from the air,
It is technologically feasible but not economically viable
What is the main challenge for CCS systems?
finding a market
