Catalyst materials for solar refineries, synthetic fuels and procedures for a...
CO2 absorption in power plants_f3
1. Athina Kouneli
Supervisor: Mathias Cehlin
Examiner: Taghi Karimipanah
2016
Faculty Of Engineering
And Sustainable
Development
Master Programme in
Energy Engineering,
Energy Online
Thesis Project
3. Kyoto Protocol
CO2 emissions reduction target for EU
compared to 1990
1st commitment period (2008-2012) 8%
2nd commitment period (2013-2020) 20%
Paris Agreement
Global climate deal, to enter in force in 2020
5. Capture (plants)
Transport
Pipelines, ships etc.
Storage
Geological formation
6. Present & compare CO2 capture technologies
Select and analyze CO2 capture with absorption
Examine the biphasic solvents as alternative option to
classic amines – Energy saving
Literature review
Scientific papers, patents, educational sites
Selection of app. 50 references / app. 100 references
7. Post combustion (separated from fuel gas
compounds)
Pre combustion (fuel production without carbon)
Oxyfuel combustion (combustion rich in O2)
8. CO2 is captured from the exhaust gases of a
combustion process. The carbon dioxide is
then compressed and transported and stored.
Capture methods
Absorption
Adsorption
Membranes
9. •Physical absorption (high concentration of CO2, at high
pressures), physical solvents, less regeneration energy
•Chemical absorption, aqueous alkaline solvent (usually
amine)
25-30% net power
output of a coal
power plant is
used for the
solvent
regeneration
10. CO2 molecules adhere to solid sorbents with
high surface area (e.g. zeolites)
intermolecular forces CO2 is separated
from the flue gases
1. Flue gas enters a bed of solids
adsorb only CO2
2. Regeneration of the bed when
fully loaded (reducing
pressure/raising the
temperature)
& (repeated cycle)
11. “A barrier film that allows selective and
specific premeation under conditions
appropriate to its function”
Gas permeation membranes
Driven force: differences in physical & chemical interaction,
Differences on CO2 partial pressure
Absorption membranes
Driven force: absorption liquid selectivity
12. 1.The fuel is converted into a mixture mainly of H2 and CO2
CO2 capture from natural gas
Steam reforming - heat supplied from outside the reformer
Partial oxidation (incl. Autothermal reforming) – heat is
generated within the reformer
CO2 capture from coal
Integrated Gasification Combined Cycle (IGCC),
2. CO2 is captured (usually physical/chemical absorption) CO2
stream (needs compression & dehydration) and a fuel rich in
H2 (boilers, furnaces, gas turbines, fuel cells)
13. CH4 + H2O CO + 3H2
CO + H2O CO2 + H2
heat
Source: Davy technologies
15. Oxygen instead of air during combustion
Flue gas mainly consisting of CO2 and H2O
Pros
After the condensation of water high CO2
concentration (80-98%), easy to compress and dry
CO2
Dilution of the flue gases because of N2 is avoided
Cons
High cost due to the oxygen production in
cryogenic air separation units
High temperatures (the flue gas is recirculated to
control the boiler temperature)
16.
17. Most promising option to be implemented on large scale in the near future
taking into account:
operating & maintenance costs
cost and ease of retrofitting a power plant
development of each technology
Absorption separation technology (Notz et al., Aaron et al.)
Major advantages
Well established process
Low complexity
Load flexibility
Main challenge
High energy demand for solvent regeneration and CO2 compression – 3.7
GJ/tonCO2 for monoethanolamine (MEA) regeneration
Biphasic solvents as alternative option???
18. After CO2 absorption they form two different
phases, one rich in CO2 and one poor in CO2
only the rich phase is regenerated
less energy used for regeneration (MEA as
comparison basis)
Biphasic solvents can exhibit:
- two liquid phases
- liquid and solid phase
19. Phase change mixed amine solvents
TETA DEEA (Ye et al.,2015) app. 30% energy reduction
DEEA MAPA (iCap project) app. 40% energy reduction
Thermomorphic biphasic solvents
App. 35% energy reduction (Zhang et al.)
DMX solvents
App. 22% energy reduction
3H self-concentrating
process
50-80% energy reduction
(Hu, 2012)
21. Carbon capture processes were presented
Comparison was made Carbon dioxide
capture with absorption, the most promising
capture technology to be used in the near
future
Biphasic solvents > 30% energy reduction in
comparison to simple amines (MEA
comparison basis)
22. Estimation of captured CO2 cost when using
biphasic solvents
Comparison with the captured CO2 cost when
using amines
Research on problems of using biphasic solvents
& how/if they could be avoided