co2 capture - eth z · steam turbine flue gas cleaning gasification, gas cleaning water-gas shift...

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Daniel Sutter, Marco Mazzotti, Christoph Müller

CCS and the Industry of Carbon-Based Resources – FS2020

March 16, 2020

CO2 capture

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CO2 capture architectures

16.03.2020 2

Recapitulation

CO, H2, H2O

Boiler,

Steam Turbine

Flue Gas

Cleaning

Gasification,

Gas Cleaning

Water-gas Shift

CO2 Capture

Gas Turbine,

HRSG,

Steam Turbine

Flue Gas

Cleaning

Condensation

ASU

AirAir

O2

CO2

Water

WaterWater

Power

Output

Fuel Fuel

Power

Output

Power

Output

Air

ASU

Fuel

N2 N2

N2H2 Air

N2

Post-Combustion Pre-CombustionOxy-Combustion

CO2, N2, H2O

O2

CO2 Capture

N2, CO2, H2O,

SO2, NOx

Boiler,

Steam Turbine

CCS and the Industry of Carbon-Based Resources - FS2020 - [email protected]

CO2, H2O,

SO2, NOx

CO2, H2O

CO2, H2

CO2

CO2

CO2

|| 316.03.2020CCS and the Industry of Carbon-Based Resources - FS2020 - [email protected]

Content

CO2 capture fundamentals

What’s the scale we are talking about?

Thermodynamics of gas separation

CO2 captured vs. CO2 avoided

Separation techniques

Post-combustion CO2 capture

Amine-based processes

Chilled ammonia process

Pre-combustion CO2 capture

Integrated gasification combined cycle power plants

Oxy-combustion CO2 capture

For solid fuels

For natural gas

Direct air capture

CO2 capture

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What’s the scale we are talking about?

For example, cement manufacturing:

Typical production facility: 1 million metric tons per year of cement (mostly CaO) ( ሶ𝑚cm)

Reaction enthalpy calcination: 178 kJ/mol (Δr𝐻calc) (see last week’s lecture)

Lower heating value of coal: 27 MJ/kg (Δc𝐻coalLHV)

Simplifying ass.: Coal consists of carbon

CO2 emissions per year?

ሶ𝑚coal =ሶ𝑚cmΔr𝐻calc

Δ𝑐𝐻coalLHV

ሶ𝑚CO2fuel = ሶ𝑚coal

𝑀CO2

𝑀C

ሶ𝑚CO2fuel =

ሶ𝑚cmΔr𝐻calc

Δ𝑐𝐻coalLHV

𝑀CO2

𝑀C

ሶ𝑚CO2fuel =

178

40+16106

27

44

12

kJ

mol

mol

g106

g

t

t

a

MJ

kg103

kJ

MJ103

kg

t

ሶ𝑚CO2fuel ≅ 430,000

t

a

ሶ𝑚CO2tot = 3 ∗ ሶ𝑚CO2

fuel ≅ 1.3Mt

a

16.03.2020 4CCS and the Industry of Carbon-Based Resources - FS2020 - [email protected]

Gardarsdottir et al.

Energies 2019, 12, 542

Think of filling a truck:

1.3Mt

a= 148

t

h= 2.5

t

min

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Minimum thermodynamic work for CO2 capture

Maxwell’s demon (a thought experiment)

16.03.2020CCS and the Industry of Carbon-Based Resources - FS2020 - [email protected] 5


Illustration: Smit et al. (2014) Introduction to CCS, Imperial College Press

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Minimum thermodynamic work for CO2 capture

For ideal gases, the minimum work

required for the separation of gases

equals their entropy of mixing

𝑊min = Δ𝑈sep − 𝑇Δ𝑆sep

For a separation at constant

temperature and pressure, the

minimum work is given by

𝑊min = 𝑛𝐹𝑅𝑇

𝑖=1

𝑁

𝑦𝑖 ln𝑦𝑖

𝑦𝑖0

As a result: the lower the

concentration of CO2 in the gas

stream, the higher the energy

demand for capture



0

Illustration: Smit et al. (2014) Introduction to CCS, Imperial College Press

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CO2 captured vs. CO2 avoided

16.03.2020

Power plantCoal w/o CCS

CO2 produced

[g/kWh]

captured

extraavoidedPower plant Coal w/ CCS

24-40% extra E90% capture

same net E-output

CCS and the Industry of Carbon-Based Resources - FS2020 - [email protected] 7


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Overview of separation techniques

Absorption

a gas or a liquid dissolves or permeates into a liquid or

solid.

Adsorption

attachment of a gas or a liquid to a surface (solid or

liquid).

Cryogenic (low-temperature distillation)

separation making use of the different boiling points of the

components (e.g. air separation)

Membranes

making use of the difference in physical/chemical

interaction with the membrane material.



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Absorption vs. Adsorption

Chemical Adsorption Physical Adsorption

Chemical Absorption Physical Absorption

Source: CO2Net









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Chemical absorption

Favourable for low pressure

separation, e.g. pulverized coal

combustion

Physical absorption

Favourable for high pressure

separation, e.g. Integrated

gasification combined cycle (IGCC)

No general preference for the

absorption of CO2

Physical vs chemical absorption

16.03.2020

CO2 capacity and partial pressure

So

lven

t lo

ad

ing

cap

acit

iy

CO2 partial pressure

Chemical absorption

(T = const.)



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Equilibrium curves for different CO2 sorbents

16.03.2020

1 Rectisol (methanol), 253 K

2 Methyldiethanolamine (MDEA)

50 wt% aqueous solution, 343 K

3 Monoethanolamine (MEA)

25 wt% aqueous solution, 333 K

4 Purisol (N-Methylpyrrolidon), 313 K

5 Selexol (dimethyl ethers of

polyethylene glycol), 313 K

Kenarsari et al., RSC Advances, 3, 22739, 2013



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Post-combustion capture

Particleremoval

Boiler

Heat

Steamcondenser

Steamturbine

Coolingwater

Electricity

Air

Fuel

Bottom ash

Cooler

Lowtemperature

heat

Lowtemperature

heat

CleanMechanical

energy

Fly ash Gypsum

Sulphurremoval

CO2

COcompressor

2

COstripper

2

CO -leanabsorbent

2

CO -richabsorbent

2

COabsorber

2

Illustration: Vattenfall factsheet 13329155

Tech Center

Mongstadt, NO

www.tcmda.com



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Retro-fitting:

CO2 is captured from the flue gas; the industrial/power

plant remains largely unchanged

Availability:

The required technologies are available and have been

demonstrated on the industrial scale, e.g. amine

scrubbing for natural gas purification.

Energy integration is possible (to some extent).



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State-of-the-art: Amine scrubbing

16.03.2020

Basic process patented in 1930.

CO2 is absorbed from a flue gas

or combustion gas near ambient

temperature in an aqueous

solution of amines with low

volatility.

The amine is regenerated by

stripping with water vapor at

110 – 150 °C. The water is

condensed from the stripper

vapour, leaving pure CO2.



R.R Bottoms (Girdler Corp.), «Separating acid gases»,

U.S. Patent 1783901, 1930

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Basic layout of an absorption process



Lean solvent

110 – 150 ºC

• Column height

∝ CO2 capture rate

• Column diameter

∝ gas flow rate

Pressure and temperature values apply

for amine-based CO2 absorption processes

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Absorbers

Gas absorption requires large reaction

volumes as gas-liquid reactions are

comparatively slow

Absorber column is filled with plates or

packings to increase the interfacial area

between the liquid and the vapour phase,

and thus, increase mass transfer

16.03.2020

Picture Source: Sulzer, 2010

Liq

uid

Gas

Column

internal:

plate

Column

internal

packing



||

Absorber at Boundary Dam capture plant


Pictures: www.boilermakers.org

Capture from coal-fired power plant, 1 Mt/a capacity

(see last week‘s lecture for details)

Shell Cansolv process (proprietary amine solvent)

Square cross section, 8x8 m

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The size of flue gas treatment equipment

Coal fired power station (660 MWe) with SO2/CO2 capture.

16.03.2020

Boiler

house

Flue gas

desulphurisa

tion

CO2

absorption

(6 abs.)6 regenerators

70 m 80 m 75 m

120 m

50 m40 m

30 m

110 m

15 m60 m

20 m70 m

CO2 capture rate: ~ 500 t/h (@ 90%)

MEA circulation: 16’000 m3/h

Efficiency loss: 10-15 % points

Increased specific investment: ~ 80-130 %

Cost CO2 avoided: 47-49 $/t CO2

Source: Koss, Lurgi AG 2005



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The most common solvents in absorption-based CO2 capture are

aqueous amine solutions

Advantages

High affinity for CO2

Low volatility

Low/acceptable viscosity

Typical examples:

Amine chemistry


Monoethanolamine

(MEA)

Piperazine

(PZ)

Methyl-diethanolamine

(MDEA)

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Physical properties of different amines

16.03.2020

Solvent MEA DEA TEA

Molar fraction (-) 0.05 0.035 0.035

Weight fraction (-) 0.3 0.36 0.5

Heat of reaction (kJ/mol CO2) 72 65 62

Reaction rate constant (mol/Ls) 7600 1500 16.8



Primary amines Secondary amines Tertiary amines

e.g. monoethanolamine (MEA) e.g. diethanolamine (DEA) e.g. triethanolamine (TEA)

More reactive than secondary

amines.

Slow kinetics (to bicarbonates)

Used to remove H2S and CO2

from natural gas.

Lower vapor pressure than

primary and secondary amines.

Formation of non-regenerable

and corrosive degradation

products with COS and CS2.

Less reactive with COS and CS2

than primary amines; reactions

do not lead to corrosion.

Less degradation than primary

and secondary amines.

Image source: chem.libretexts.org

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Reaction mechanisms

Primary and secondary amines

Primary amines: CO2 + 2 RNH2 RNH3+ + RNHCOO

−

Secondary amines: CO2 + 2 R2NH R2NH2+ + R2NCOO

−

Fast reaction kinetics

Formation of a carbamate

Maximum CO2 loading: 0.5 mol CO2/mol amine



https://theorganicsolution.wordpress.com/2012/11/

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Reaction mechanisms

16.03.2020

Tertiary amines

CO2 + R3N + H2O R3NH+ + HCO3-

Slow reaction kinetics

Formation of bicarbonate in the presence of water

Maximum CO2 loading: 1.0 mol CO2/mol amine



Methyl-diethanolamine

(MDEA)

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Performance of amine scrubbing

Significant improvements in energy consumption

Amine degradation controlled through

Flue gas pre-treatment (de-SOx)

Solvent reclaiming

Flue gas wash

Water wash stage

Acid wash stage

Increased plant complexity,

no showstoppers


Rochelle et al. Chem. Eng. J. 2011, 171, 725–733

Thermodynamic limit

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Overview CO2 capture technologies


Source: Bui et al, Carbon capture and storage (CCS) the way forward, 2018

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Basic layout of an absorption process



Lean solvent

110 – 150 ºC

|| 16.03.2020CCS and the Industry of Carbon-Based Resources - FS2020 - [email protected] 27

Chilled ammonia capture (with GE, Baden)

Solvents Process design Process optimization



Chilled ammonia capture (with GE, Baden)

CAP with solid formation

Solvents Process design Process optimization

0

10

20

30

40

50

60

70

80

90

100

1 2K

ey

con

trib

uti

on

s to

en

erg

y p

en

alty

[%

] CO2 compression

Heat rejection

Pump

Chilling

NH3 reboiler

CO2 reboiler

Standard CAP

CrystallizerCAP


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Source: CO2Net









||30

Adsorption separation processes

a) Thermal swing adsorption (TSA)

Tabs (low)

Tdes (high)

Pproc (constant)

• For strong adsorbed components

• Adsorbate can be recovered at

high concentration

• No rapid cycles (thermal inertia)

• Thermal aging of the adsorbent

-

Examples: Gas drying or organic solvent drying


Direct air capture of CO2 from air

+

||31


b) Pressure swing adsorption (PSA)

Pads

• For rapid cycles

• The weak adsorbents can be

adsorbed at high concentration

• Mechanical energy is expensive

• Vacuum may be needed

-

Examples: recovery and purification of H2,

air separation

pre-combustion CO2 capture

Direct air capture (VTSA)

+

Pdes

Tproc (constant)

||32


b) Pressure swing adsorption (PSA) Light product

Blowdown

HP HP LPLP HP

Pressurization

LP

PurgeProduction

WasteWaste

Feed Feed

Skarstrom cycle

|| 33

Design of TSA cycles for CO2 capture

CO2

Heat. Cool.Ads.time

dry flue gas

N2

CO2

Hot fluegasCO2, N2, H2O

TSAN2

H2ODrying

8 MJ/kgH2OCold

fluegas

Case study

CO2/N2 12:88 v/v (dry)

4 vol% H2O

Shell and tube type adsorber

Cooling at 300 K, heating at 420 K

How to design a TSA process ableto reach the CCS specifications

1. Cycle Design

2. Novel Materials


|| 34


Dryfeed

time

CO2

Heating CoolingAdsorption

Base cycleWaste

(N2)Zeolite 13X: - Aluminosilicate- Cage structure- 7.4 Å pore diameter

Parametric analysis

Maximize CO2 purity,

maximize CO2 recovery,

by varying the step times for different cycles.


|| 35


Dryfeed

time

CO2

Heating CoolingAdsorption

Base cycleWaste

(N2)

Joss et al, Chem. Eng. Sci 158 (2017) 381-394

13XBase cycle

Recovery ≥ 90% Purity ≥ 96%

Parametric analysis

Maximize CO2 purity,

maximize CO2 recovery,

by varying the step times for different cycles.


|| 36


Patent filed 25.5.2016

CoolingHeat 2

Waste (N2)

Adsorption

Dryfeed

time

CO2

Base cycle

Targeted modifications:

Base cycle




|| 37



CoolingHeat 2

Waste (N2)

Adsorption

Dryfeed

time

Purge

CO2

Improved cycle

CoolingHeat 2

Waste (N2)

Adsorption

Dryfeed

timeRec. Purge

CO2

Improved cycle


1. Nitrogen purge beforecooling/adsorption

2. CO2-rich recycle before heating

Increased recovery

Base cycle

Improvedcycle


Increased purity



|| 38



Heat 1 CoolingHeat 2

Waste (N2)

Adsorption

Dryfeed

timeRec. Purge

CO2

Advanced cycle


1. Nitrogen purge before cooling/adsorption

2. CO2-rich recycle before heating

3. Preliminary heating to remove N2 from product

Increased recovery

Increased purity

Base cycle

Improvedcycle


Advanced cycle



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Zeolite 13X:

- Aluminosilicate

- Cage structure

- 7.4 Å pore diameter

MOF-Mn [Nature, 519, 303-308 (2015)]:

- diamine-appended MOF-74

- Channel structure

- 18.4 Å pore diameter

- Cooperative CO2 insertion

CO2 Capture by TSA (with Casale, Lugano)




Summary post-combustion CO2 capture

Chemical absorption processes are dominating the field

Amine-based processes as state-of-the-art

Several plants built around the world by different competitors, e.g.

Boundary Dam, Canada (~1 Mt/year)

Chilled ammonia process as promising alternative on the verge of

commercialization

Adsorption processes

Often ruled out for post-combustion capture due to high flue gas

compression costs in case of pressure-swing adsorption

Temperature-swing adsorption as alternative development; at very

early stage


||



ElectricityElectricity

Air

Air

Fuel

Oxygen

Nitrogen

Hydrogen

Air

separation

Gasi

Steam

Steam

Particle

remover

Sulphur

removal

Fly ash

Heat

Shift

reactor

Bottom ash

Heat

recovery

steam

generator

Gasturbine

Water

vapour

(and

excess air)

Mechanical

energy

Mechanical

energy

Cooling

water

Steam

condenser

CO2

CO

desorber2

CO

absorber2

Gypsum

(HRSG)



||


ElectricityElectricity

Air

Air

Fuel

Oxygen

Nitrogen

Hydrogen

Air

separation

Gasi

Steam

Steam

Particle

remover

Sulphur

removal

Fly ash

Heat

Shift

reactor

Bottom ash

Heat

recovery

steam

generator

Gasturbine

Water

vapour

(and

excess air)

Mechanical

energy

Mechanical

energy

Cooling

water

Steam

condenser

CO2

CO

desorber2

CO

absorber2

Gypsum



IGCC: Gasification of solid fuel enables use of high-efficiency combined

cycle of a gas turbine and a steam turbine

Higher efficiency and lower emissions than coal combustion, but

complex gasification technology (OPEX vs. CAPEX)

Opportunity to capture CO2 at high partial pressure

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Reactions in pre-combustion CO2 capture

Step 1:

Gasification: C + ½ O2 CO

Steam methane reforming: CH4 + H2O CO + 3 H2

Step 2:

Water-gas-shift: CO + H2O H2 + CO2

Step 3:

CO2 removal, e.g. by pressure-swing adsorption or amine

scrubbing

Step 4:

Carbon-free fuel (H2) to be used for power generation or

other applications16.03.2020CCS and the Industry of Carbon-Based Resources - FS2020 - [email protected] 43


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Gasification

is the conversion of solid and liquid materials into syngas

(mixture of H2 and CO)

has been employed for more than 100 years, e.g.

production of town gas («Stadtgas»)

3 major types of gasifiers

Entrained flow (co-current flow of solid fuel particles and gas)

Fluidized bed (gas «bubbles» through bed of solid fuel particles)

Moving bed (gas flows through packed bed of solid fuel particles )


||

Steam methane reforming

Endothermic, CH4 + H2O 3 H2 + CO

(ΔH = + 206 kJ/mol)

Produces 7.05 kg CO2 per kg of H2.

Typically Ni-based catalysts are used.

High temperatures 700-1100 °C and ~ 40 bar.



||

Water-gas-shift (WGS) reaction

Exothermic, CO + H2O H2 + CO2 (ΔH = -41.2 kJ/mol)

Often performed in two stages

1. High-temperature WGS in the temperature range 400-550 °C,

Fe-Cr-based catalyst,

Outlet CO mole fraction 2-3 % (dry basis)

2. Low-temperature WGS in the temperature range 180-350 °C,

Cu-based catalyst,

Outlet CO mole fraction 0.2-1% (dry basis)



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Absorption

Elevated pressure (40 bar) of

the produced H2-CO2 gas

stream enables physical

absorption processes, e.g. the

Rectisol process (methanol)

Adsorption

Adsorption processes are

highly competitive at these

elevated pressures


CO2 capture from H2-CO2 mixture

Fixed bed adsorption experiment showing

CO2 and H2 separation on activated carbon(N. Casas, ETH Dissertation, 2012)

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Outlook pre-combustion CO2 capture

Typical applications are IGCC and natural gas reforming

Main barriers for IGCC deployment

High CAPEX (equipment for high pressure and temperature, solid

handling, gas cleaning, etc.)

Poor reliability due to process complexity

Long start-up times

Prominent example for difficult implementation of IGCC:

Kemper County (first large-scale IGCC with CO2 capture)

Current revival of plans for hydrogen economy may

support additional pre-combustion capture

implementations from solid and gaseous fuels


||

Outlook pre-combustion CO2 capture

Current revival of plans for hydrogen economy may

support additional pre-combustion capture

implementations from solid and gaseous fuels


For example: ELEGANCY

A Horizon 2020 project on

Low-carbon economy via

hydrogen and CCS

||

Oxy-combustion capture

Particle

removal

Boiler

Steam

condenser

Steam turbine

Cooling water

Electricity

AirOxygen

Fuel

Bottom ash

Recycled

(CO and water vapour)

Fly ash

Gypsum

Sulphur

removal

Mechani calenergy

Water

Cooler and

condenser

Air separation

Nitrogen

Mechani cal

energy

2

CO2

CO

compressor2


Schwarze Pumpe, DE, Vattenfall



||


16.03.2020

First proposed in 1982 by Abraham to produce CO2 for Enhanced Oil Recovery

(EOR).

The fuel is combusted in a nitrogen free atmosphere, i.e. in a mixture of oxygen

(> 95 % purity) and recycled flue gas.

Thus, a gas consisting mainly of CO2 and H2O is produced. The water can be

condensed and the CO2 is ready for sequestration.

The main separation task switches from CO2/N2 (post-combustion) to O2/N2

Furnace

Air

separa

tion u

nit

Air

O2

FuelGas clean-up

and coolingCO2

H2O/SO2flue gas recycle



N2

CO2, H2O

||

Processes to separate air into O2 and N2

Cryogenic distillation

Pressure swing adsorption (different adsorption coefficients of oxygen and nitrogen to e.g. a molecular sieve)

Membranes (high permeability and selectivity; currently only on the small scale)

Chemical looping combustion (novel combustion process, oxygen is provided from a solid oxygen carrier, e.g. a transition metal oxide)



||

Cryogenic air separation

Air has to be liquified to allow its separation into oxygen

and nitrogen (via distillation). The boiling point of N2 and

O2 is - 195.8 °C and -183 °C, respectively.

Distillation: Due to the different vapour pressures of

oxygen and nitrogen (pN2 > pO2), nitrogen is enriched in

the vapour phase of a boiling N2/O2 mixture and oxygen is

enriched in a condensate of a N2/O2 vapour.

Based on this principle Carl von Linde constructed the

first air separation plant in 1902.



||

Cryogenic technology for oxygen and argon



Vinson Computers and Chemical Engineering 30 (2006) 1436–1446

||

ASU: technology grid



Vinson Computers and Chemical Engineering 30 (2006) 1436–1446

||

World-largest multi-train air separation plants

16.03.2020

For enhanced oil recovery

(EOR), Pemex, Mexico:

63’000 t/day nitrogen

17’500 t/day oxygen

Source: Cryogenic air separation (Linde Group),

http://www.linde-le.de/process_plants/air_separation_plants/documents/L_2_1_e_09_150dpi.pdf



Shell Pearl GTL plant

Ras Laffan – QatarLinde ASU, 1 million Nm3/h O2,

8 trains

||

Flue gas recirculation (FGR)

Moving from air to pure O2 changes the properties of the

combustion gas significantly (density, heat transfer,

adiabatic flame temperature, etc.).

The recirculation of flue gas allows to increase the

concentration of the inert gases (i.e. those that do not take

part in the combustion reaction). In principle, the inert N2 is

replaced by recycled CO2, which is also inert.



||


To obtain a similar adiabatic flame temperature (as in

conventional combustion) ~ 60 % of the flue gases has to

be recycled. The O2 concentration is ~ 30 % higher than in

the conventional combustion process, viz. ~ 27-28 %.

The gas emissivities of CO2 and H2O are high. To obtain a

similar radiative heat transfer the O2 concentration has to

be < 30 %.



||


The flow rate through the burner is reduced resulting in

combination with the higher radiative heat transfer in a

lower convective heat transfer. The volume of the flue gas

is reduced by 80 %.

NOx emissions (per unit energy) are significantly reduced

when compared to the conventional combustion process

(absence of nitrogen from the air).



||

Results from pilot scale units

No major technical problems were encountered

Can be implemented as a retrofit technology (but

influences combustion and heat transfer characteristics)

Lowers NOx emissions (per unit energy) and possibly also

lower SOX emissions.

CO2 concentrations exceeding 95 % can be achieved.

Oxy-combustion so far only shown in boilers, not in gas

turbines, due to difficulties around FGR

( look for “Allam cycle” if interested in oxy-combustion

gas turbines)



||

Cost of CO2 capture and storage (power plants)

16.03.2020

Source: Rubin, Davison, Herzog / International Journal of Greenhouse Gas Control 40 (2015) 378–400


Costs of CCS

||

Recap: Direct air capture (DAC)

6316.03.2020CCS and the Industry of Carbon-Based Resources - FS2020 - [email protected]

Requirements DAC:

High-enough affinity for CO2 to allow uptake at atmospheric

concentration (400 ppm = 0.04%)

Negligible pressure drop

For 1 kg of CO2, approx. 300‘000 m3 of air have to be treated

(assuming a 50% CO2 recovery)

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Recap: CCS and CCU

6416.03.2020CCS and the Industry of Carbon-Based Resources - FS2020 - [email protected]

||

Solvent

Aqueous hydroxide sorbents

(mostly CaOH, NaOH, KOH and

combinations thereof)

Regeneration

High-temperature heat with

subsequent heat recovery

Companies

Carbon Engineering

Sorbent

Supported alkali carbonates

(e.g. K2CO3 on mesoporous

Al2O3 support)

Amine-functionalized supports

Regeneration

Low-/medium-temperature heat

and often vacuum

Companies

Climeworks

Global Thermostat

Infinitree


Direct air capture – Technology

AdsorptionAbsorption

||

World’s first company

supplying atmospheric CO2 to

customers

Modular CO2 capture plants

Scale-up via mass production

of CO2 collectors

Low-temperature heat

(renewable or waste) as main

energy source

Minimal carbon footprint:

90% net C-efficiency (mid-term

target 95%)


Where Climeworks is leading

||

Combination of pressure and temperature differences between adsorption and

desorption step Vapor-Temperatue-Swing Adsorption (VTSA)

Adsorption at ambient temperature and pressure


Climeworks technology


DAC markets

RENEWABLE FUELS

CARBON DIOXIDE REMOVAL (CDR)

• Onsite CO2 supply for bottlers, greenhouses, etc.(existing CO2 markets)

• 30 million tCO2 / year (source: Global CCS Institute)

• Status: DAC becoming competitive in remote locations,

where conventional CO2 has expensive logistics

• Onsite CO2 supply for renewable fuel synthesis

• 2 billion tCO2 / year (source: CO2 Sources & The Global CO2 Initiative)

• Status: Market not yet developed, several pilot projectsacross Europe

• Large-scale CO2 removal from air

• Status: Market not yet developed. Climeworks offering first CDR certificates

• 12 billion tCO2 / year (source: IPCC)

NICHE MARKETS


CarbFix 2: Geological storage of air-captured

CO2

||

Take-home messages: CO2 capture basics

CO2 capture requires extra energy and entails costs. Currently, the

societal costs of CO2 emissions are negative externalities, meaning

that capture costs appear as “additional” costs.

No clear winner among currently available post-/pre-/oxyfuel-

combustion technologies

Variety of applications (coal/natural gas power plants, industrial plants

in different environments) requires a portfolio of capture technologies.

2nd and 3rd generation technologies are already in the pipeline; have

the potential to outperform current technologies (more next time)

Projections of future capture costs are difficult

1st of a kind vs. nth of a kind

Future technological developments difficult to predict

Market interference due to huge scale of CO2 capture (e.g. price of amine

if capture is done on the large scale)


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Backup


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Environmental challenges of amine scrubbing

16.03.2020

Amines + water

CO2O2

SO2

NOx

reversible

irreversible

Formation of

stable salts

Formation of

ammonia and

aldehydes and

further degradation

productions

nitrates/nitrite

Nitrosamine/nitramine



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Formation of nitrosamines

Nitrosamines through the reaction of amines with a nitrosyl

cation, i.e.

R2N-H + [N=O]+ R2N-NO + H+

Nitrosyl cations can form from NOx (NO2 equilibrates with NO

in the flue gas to form N2O3), e.g.

N2O3 + H2O 2 HNO2

HNO2 + H3O+ [N=O]+ + 2 H2O



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Nitrosamines

Formation potential from amines: secondary > tertiary >

primary.

Strongly carcinogenic compounds.

Ideally secondary amines should be avoided, but

secondary amines are impurity in alkylated amines.



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EU Horizon 2020 project

Development and comparative assessment of 6 different

capture technologies for cement plants


CO2 capture from cement plant –

CEMCAP project

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CEMCAP capture technologies

MEAmonoethanolamine

CAPchilled ammonia process

CaLCalcium looping

CaL-intCalcium looping integratedMAL

membrane-assisted liquefaction

OxyOxy-combustion



CEMCAP results

0

20

40

60

80

100

120

Referencecementplant

MEA Oxyfuel CAP MAL CaLtail-end

CaLIntegrated

EF

Cost of

clin

ker

[€/t

clk]

Steam

Electricity consumption/generation

Coal

Raw material

Other variable cost

Fixed operating costs

CAPEX

Total cost of clinker

colour / sign meaning, explanation

✔ retrofitability o.k.; suitable in most cases/plants; in most cases no or significantly less

attention needed

! some attention needed for plant retrofit; assessment of plant specific conditions is

important

!! special attention needed for plant retrofit; key parameters have to be assessed in

relation to site specific retrofitability

? needs further assessment for plant retrofit; lack of important information

X retrofit not possible

Portfolio of capture

solutions available

Each specific cement

plant may require a

different solution

depending on the plant

and its environment

Experience and

„retrofitability“ differ

co2 capture - eth z · steam turbine flue gas cleaning gasification, gas cleaning water-gas shift...

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