CCS

Question 1

What is carbon capture and storage?

Answer 1

CO2 can be captured from a process or the atmosphere and permanently stored geologically

Question 2

Why is CCS important?

Answer 2

fossil fuels will remain a major source of energy globally

Question 3

What are the 3 categories of carbon capture systems?

Answer 3

Post-combustion capture
pre-combsution capture
oxt fuel combustion

Question 4

What is post-combustion capture?

Answer 4

Separate CO2 from gas mixture after combustion

Question 5

What is pre-combustion capture?

Answer 5

Sperate CO2 from the production of H”, combust the H2

Question 6

What is oxy-fuel combustion?

Answer 6

Combust fuel in O2, no further spearation needed

Question 7

What is the parasitic energy for post-combustion capture?

Answer 7

~20%

Question 8

What are the benefits of post-combstion capture?

Answer 8

retrofitable

Question 9

Is it cheaper to retrofit or build post-combustion capture with the power plant?

Answer 9

Build with power plant
£570MM new
£700MM retrofit

Question 10

What are the advantages of post-combsustion capture?

Answer 10

• retrofittable
• mature technology
• experience with ‘large-scale’ in the oil and gas indsutry
• flexible

Question 11

What are the disadvantages of post-combustion capture?

Answer 11

• high CapEx - large gas volumes - large equipment
• parasitic energy
• solvent disposal

Question 12

How does pre-combustion CO2 capture work?

Answer 12

react fuel with steam and small amount of O2, produces syngas

• reduce syngas to get CO2 and H2
• H2 used as a fuel

Question 13

How does post-combustion capture work?

Answer 13

• 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

Question 14

What are the advantages of pre-combustion capture?

Answer 14

• uses processes that are already commercially used
• lower energy penalty than post-comustion capture
• can be very efficient

Question 15

What are the disadvantgaes of pre-combustion capture?

Answer 15

• high CapEx
• complex - low flexibility
• no commercial scale demonstration

Question 16

How does oxy fuel combustion work?

Answer 16

• O2 separated from air
• mixture of O2 and CO2 used to combust fuel
• no further separation required

Question 17

what kind of air seperation methods are there?

Answer 17

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

Question 18

How is CO2 transported?

Answer 18

Large scale:
pipeline, ship

Small scale, trucks rail

under pressure (100 bar 30C) 
liqufied (37C 11 bar) 

either way significatn energy requirement

Question 19

In a pipeline what do we have to consider?

Answer 19

The number of sources
the distance
the number of sinks

Question 20

How do we store Co2?

Answer 20

We can inject it into the ground

Question 21

How long does CO2 stored in the ground remain there for?

Answer 21

over 10,000 years

Question 22

What is the current CO2 storage research focusing on?

Answer 22

site characterisation
plume mitigation
managing risks of leaking
detecting leaks with certainty

Question 23

How much more expensive than other technologies is CCS?

Answer 23

Substantially - cost will go down if adopted though

Question 24

what is direct air capture DACCS?

Answer 24

When CO2 is adsorped from the air,

It is technologically feasible but not economically viable

Question 25

What is the main challenge for CCS systems?

Answer 25

finding a market