co -lean energy conversion technologies with fluidized bed ... · carbonator t = 650 °c co 2 + cao...

Institute of Combustion and Power Plant Technology

Prof. Dr. techn. G. Scheffknecht

CO2-lean energy conversion technologies with fluidized bed systems

74. International IEA-FBC meeting

Krakow, 21th Mai 2017

Marcel Beirow

2 University of Stuttgart - Institute of Combustion and Power Plant Technology -

Expertise in Lime based Fluidized Bed Processes

M.Sc. M. Beirow


Multifunctional fluidized bed pilot plant system

M.Sc. M. Beirow

CO2 Capture: >90%

Temperature: 600-700°C

Flue Gas: 200-330 m³STP/h

Height: 10 m

Diameter: 0.23 m

Velocity: 4-6 m/s

Inventory: 40-60 kg

Carbonator Combustor / Calciner Flue / Product

Gas

CO2-rich Gas

Flue Gas Air, O2, CO2

Combustor /

Carbonator / Gasifier

CO2-lean Gas


Powerth: 150-330 kW

Height: 10 m

Diameter: 0.21 m

Velocity: 3-6 m/s

Inventory: 20-40 kg

CO2-Conc. exit: >90%


Powerth: 130-230 kW

Height: 6 m

Diameter: 0.33 m

Velocity: 0.5-4 m/s

CO2-Capture: >90%

Inventory: 40-100 kg

Solids:

Circulation rate: 0-1500 kg/h

Make-up: 0-50 kg/h

Air, H2O, CO2

Cone valve

Screw conveyor

Solid stream Gas stream

FBHX

Oxy-fuel combustion


Combustion investigations in CFB systems

M.Sc. M. Beirow

• Oxidants and staging:

• Air,

• Oxygen enriched air,

• Oxy-fuel with flue gas recirculation experimental data will be shown in presentation

of M. Hornberger at CFB12 conference

Tertiary + O2

Secondary + O2

Primary + O2

CO2-rich flue gas recirculation

Fuel

Recirculation blower power demand can be decreased

with higher O2 concentrations (less dilution required)

Flue gas

recirculation

blower

Calcium Looping Process


Calcium Looping – Post Combustion CO2 Capture

Flue Gas

CO2-lean Flue

Gas

Fuel Flue Gas

Air / O2

CO2-lean

Flue Gas

Configuration A (CFB-CFB) Configuration B (TFB-CFB)

CO2-rich Gas

Fast fluidized Carbonator

High carbonator velocities

& flue gas throughput

High gas-solid contact

Short gas residence time

Turbulent Carbonator

good gas-solid contact

lower entrainment than

fast fluidized CFB

high gas residence time

Reduction of attrition

CaO

CaCO3

CaO

CaCO3


High temperature heat utilization and integration


Flue Gas

Air

Coal

ASU

O2

N2

CO2-depleted Flue Gas

CO2-enriched Flue Gas

CO2 to Storage

CaCO3

CaO Calciner T = 900 °C

CaCO3 + ΔRH CO2 + CaO

CO2 Conditioning

Make-up Limestone Purge

Carbonator T = 650 °C

CO2 + CaO CaCO3 + ΔRH

Flue Gas Source

CaL Steam Generator

G

1) Process extension with

steam cycle for power

generation

• Increase efficiency

• Ca-based CO2 capture for

power plants or other

industrial processes

• cheap, natural sorbent

• Retrofittable

2) Option to reduce coal

consumption in calciner:

solid/solid heat exchange

M.Sc. M. Beirow


Clinker

Further level of process integration: Cement production


M.Sc. M. Beirow

Flue Gas

CO2-lean Flue Gas

Fuel

Air / O2

CO2-rich Flue Gas

CaO

CaCO3

Cement Plant

Air

Benefits of CaL

• CO2 capture from flue gas from cement plant

• Sorbent utilization for cement production process

• Reduction of auxiliary power demand by

integration of a steam cycle

Fuel

Sorption Enhanced Gasification


CO2-rich

Flue Gas

Sorption enhanced steam gasification

Fuel

(Biomass)

Steam

CaO

CaCO3

+ Char

Gasifier Calciner Extention to CaL process:

• Adding fuel (biomass) into „Carbonator“ Gasifier

• Steam as fluidization agent (instead of flue gas

from industrial processes)

• Heat input for endothermal gasification reaction via

solid circulation

• In situ capture of CO2 (from pyrolysis, gasification)

high product gas quality (nitrogen-free)

high tar cracking capability of CaO

WGS reaction is shifted towards high H2

concentrations in product gas

M.Sc. M. Beirow

Air / O2

CO2-lean,

H2-rich

Product Gas

In situ CO2 - capture

CO2 + CaO ↔ CaCO3 (1)

Water Gas - Shift

CO + H2O ↔ CO2 + H2 (2)

Gasification temperature: 600°C - 725°C


Product gas composition for different gasification temperatures


M.Sc. M. Beirow

• Hydrogen concentrations of up to 75 vol%dry at gasification temperatures of ≈ 600 °C


Characterization of product gas composition by stoichiometric conversion

parameter


M.Sc. M. Beirow

• High flexibility of gasification for numerous downstream synthesis processes

• „CO2-neutral“ emissions due to usage of biomass

Sto

ichio

me

tric

co

nve

rsio

n

pa

ram

ete

r, (

yH

2-y

CO

2)/

(yC

O+

yC

O2)



M.Sc. M. Beirow

• With O2 source (e.g. ASU, water electrolysis system) Oxy-fuel calcination is possible

• CO2-rich calciner outlet gas stream can also be utilized in synthesis processes

Switching between operation modes can be used for stabilization of power transmission grid

Air calcination Oxy-fuel calcination

Operation strategies for the calciner


Switching from air to oxy-fuel calcination


M.Sc. M. Beirow

Smooth switch of the calciner to oxy-mode:

Calciner: - Steep increase in CO2 concentrations (up to > 80 vol%dry)

- Minimal impact on calciner temperature

Gasifier: - Gasifier operation is not affected by regenerator operation mode

- constant temperature and gas composition in gasifier


With Switching

Potential of calciner operation strategies for power grid stabilization

M.Sc. M. Beirow

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

Ca

pa

city le

ve

l in

%

• Based on biomass availability, SEG gasifiers

are installed close to the power grid

• Region-sharp consideration of load flows:

Power lines between regions are aggregated

as „flowgates“ (arrows in map)

• Linearised load flow calculations according to

PTDF* approach

• Calciner operation is based on information

from power grid

• Example

Point in time serie: Capacity level in flowgate

between northern Bavaria and northern

Baden-Württemberg could be reduced *Power Transfer Distribution Factor

Load flow calculations in German power transmission grid


• High O2-concentrations in Oxy-fuel combustion can reduce auxiliary power demand

• Calcium looping process can be carried out in different configurations (CFB-CFB, TFB-

CFB) to consider aspects of residence time, gas throughput or attrition to enable an

individual process adaption

• Heat utilization into an integrated steam cycle increases the process efficiency

• Calcium Looping with cement plants enables additional sorbent utilization

• With Sorption Enhanced Gasification syngas composition can be adjusted for different

downstream synthesis processes

• Oxy-fuel operation of calciner enables a CO2-rich flue gas, which could also be utilized

for synthesis processes and hence, 100% of carbon in the biomass could be used

• Process flexibility to switch between air and oxy-fuel calcination can contribute to

stabilize the power transmission grid

Conclusion

M.Sc. M. Beirow

e-mail

phone +49 711 685-

fax +49 711 685-

University of Stuttgart

Thank you!

Pfaffenwaldring 23 70569 Stuttgart Germany

Institute of Combustion and Power Plant Technology

Marcel Beirow

68938

63491

[email protected]

co -lean energy conversion technologies with fluidized bed ... · carbonator t = 650 °c co 2 + cao...

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