Carbon Capture

Question 1

Which sectors can Carbon capture be applied to and not applied to

Answer 1

Industry, heating and electrical sector. It’s not really possible for the transport sector

Question 2

What are the three CCS categories

Answer 2

Post, pre and oxy combustion .
Post - separate CO2 from gas after combustion
pre - separate CO2 from the fuel and combust the h2 from the fuel
oxy - combust fuel in oxygen

Question 3

What is the advantage and disadvantage of chemical post combustion capture

Answer 3

The capture system can be placed at the end of any fuel processes, meaning that the processes need not be changed. However it does require 20% of the energy produced

Question 4

Disadvantage of amine based post combustion capture

Answer 4

The amines can degrade into potentially harmful chemicals. To reduce degradation will require systems that use energy.

Question 5

What is adsorption and what governs the level of adsorption

Answer 5

The adhesion of species to a solid surface. Governed by pressure, concentration and temperature. Heating up or reducing the pressure will cause the adsorbed species to fall of.

Question 6

What are the two types of adsorption technologies for carbon capture

Answer 6

VSA (pressure/ vacuum) and TSA (temperature) . TSA captures more carbon but take longer to clean.

Question 7

What is the benefit of adsorption CSS compared to chemical/ amine CSS

Answer 7

Less energy required

Question 8

How does Pre combustion CSS work

Answer 8

The carbonaceous fuel, such as natural gas, is reacted with steam and a small amount of O2. This produces syngas a mixture of co2, co, ch4 and h2. This syngas is further reacted to form only co2 and h2. The co2 is then removed, keeping the h2

Question 9

what are the four ways of precombustion CCS

Answer 9

adsorption, chemical absorption, distillation, physical absorption.

Question 10

What is the main disadvantages of adsorption precombustion ccs

Answer 10

Complex process.

Question 11

What is the main disadvantage of cryogenic distillation

Answer 11

Requires cooling the feed, which is not feasible unless co2 content is greater than 40%

Question 12

Adv and disadv of precombustion CCS

Answer 12

lower energy penalty, efficient and uses widely used technologies
Complex process so low flexibility and quite high capital expenditure

Question 13

What is oxy fuel combustion

Answer 13

The fuel is combusted in oxygen removed from the air and co2 which forms water and co2, the water vapour is released and the co2 is captured.

Question 14

How is oxygen removed from the air for oxy fuel combustion and state the pros and cons

Answer 14

cryogenic distillation - mature tech, very high capacity, very high purity, high energy requirements
vacuum swing Adsorption - mature tech, medium capacity, high purity, low energy requirements
membranes - high purity, low capacity

Question 15

How is captured carbon transported

Answer 15

As a supercritical liquid (high pressure, normal temp) or a normal liquid (normal pressure, low temperature). Both require large amounts of energy, as much as the capture itself.
Transported in pipes, ships or when in small scale (not often economically viable) trucks, rail

Question 16

What is captured carbon used for

Answer 16

EOR - injection of co2 down into oil reserves to pump the oil out
Stored underground in caves
creation of plastics and other chemicals

Question 17

What makes co2 separation easier

Answer 17

A more concentrated co2 flue composition. For example steel and cement plants have above 20% co2 mol so are easier to separate.

Question 18

What is the problem with carbon transport

Answer 18

The pipes have to pass through many landowners’ land.

Question 19

Why does greenhouse gas removal need to be performed earlier

Answer 19

The longer co2 remains in the atmosphere, the more of an effect it has (somehow) which means emitting 1 tonne of co2 now means more than 1 tonne needs to be removed later??

Question 20

What is the pros and cons of Bioenergy with CCS

Answer 20

feasible tech, but has social stigmas as it seems like wasted land to grow crops for the sole reason of capturing carbon only to burn it again for energy,

Question 21

What is the pros and cons of direct air capture (adsorption of co2 from air)

Answer 21

Technically feasible, socially acceptable but economically questionable. A less visible disadvantage is that it encourages corporations to use direct air capture instead of post combustion co2 capture. The co2 becomes diluted so this process is incredibly inefficient in comparison

Question 22

barriers to deployment of CCS

Answer 22

policies. There is no penalty for not executing CCS properly so no incentive for trying to utilise it
There is little information of the entire operation of CCS as it hasn’t been deployed enough
It is expensive and does not generate revenue
The general public doesn’t care enough
co2 doesn’t have much value