CO 2 capture research at Chalmers Filip Johnsson Department of - - PowerPoint PPT Presentation

Chalmers University of Technology

CO2 capture research at Chalmers

Filip Johnsson Department of Energy and Environment, Energy Technology 412 96, Göteborg filip.johnsson@chalmers.se SIAMUF – Seminarium Flerfasströmning – Tema Energi

Chalmers University of Technology

Outline

• Introduction
• Oxyfuel combustion
• Chemical looping combustion

Chalmers University of Technology

Alternatives towards Sustainable Energy Systems

• General
• To use less energy

– Population – Technology – Affluence and life style – Efficiency measures

• To shift fuel

– Renewable energy – Nuclear – Coal to gas

• To Capture and Store CO2

– From large point sources (power plants, industry, hydrogen from fossil fuels) – Carbon sequestration (Land Use Change and Forestation- LUCF)

We need all! We need all!

Chalmers University of Technology

Example China

• Around 300 GW coal based power being added

2006-2010 ! 700 Mt coal ! 1.7 Gt CO2

• Similar to the EU targets on emission reductions

until 2020 (1.1 – 1.7 Gt)!

Chalmers University of Technology

CO2 Capture, Transport & Storage (CCS)

Chalmers University of Technology

Three main principles for CO2 capture

Chalmers University of Technology

Planned and proposed CCS demos

Chalmers University of Technology

Oxyfuel combustion

Chalmers University of Technology

The basic principle of oxy-fuel combustion

Typically 2/3 of the flue gas is Typically 2/3 of the flue gas is recirculated recirculated

Chalmers University of Technology

Conditions in oxy-fuel combustion

Table 1. Rough overview of properties of the flue gas in an oxy-fuel power plant (see Figure 1 for stream numbers). ! Stream 1 2 3 4 5 6 7 Pressure (bar) 1 1 1 30 30 100 1 Temperature (°C) 300 300 20 20

• 30

20 20 Mass Flow 1 1/3 1/3 1/3 1/4 1/4 1/25 Volume Flow 1 1/3 1/7 1/200 1/900 1/1000 1/40 Phase Gas Gas Gas Gas Liquid Fluid* Gas

* Supercritical fluid.

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First assessment of the oxfuel process

• reference power plant Lippendorf

Lignite-fired 2x865 MWel, !el=0.426 Comissioned in 2000 10 million tonnes CO2/year

Chalmers University of Technology

Process layout of the O2/CO2 Power Plant

Flue gas treatment Air Separation Unit Power plant

• 2

N2

• 2

O2

1 2 3 4 5 6 7 8

Air inlet

9 10 11 14 13 12 16 15 20 19 18 17 23 22 21 26 25 24 28 27 30 29

CO2

• ut

31

B C

32

A

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The CO2 avoidance cost

w – with capture, w/o – without capture

) / / ( ) / ( ) / (

2 / 2 / w

• w
• w

w

MWh CO tonne MWh CO tonne MWh EUR MWh EUR " "

Process analysis Process analysis # # approximately 20 approximately 20 € €/tonCO /tonCO2

2

(depends on interest rate and fuel price!) (depends on interest rate and fuel price!)

Chalmers University of Technology

Aim and focus of the Oxy-fuel group

Aim: To provide fundamental knowledge on oxy-fuel combustion required for design, scale-up and optimization of oxyfuel combustion process Focus: Combustion experiments & modeling Combustion experiments & modeling " " Heat transfer Heat transfer " " Chemistry Chemistry " " Mixing Mixing Primary and secondary measures Primary and secondary measures for pollutant control for pollutant control

Chalmers University of Technology

Oxyfuel – Intense development

Lab scale (IVD 10 kW) Lab scale (IVD 10 kW) Basic research Basic research Small pilot (Chalmers 100 kW) Small pilot (Chalmers 100 kW) Basic research Basic research Pilot/Demo ( Pilot/Demo (Vattenfall Vattenfall 30 MW) 30 MW) Testing of new products (2008) Testing of new products (2008) Demo/full scale (2015 Demo/full scale (2015-

• 2020?)

2020?) Early market introduction Early market introduction

Chalmers University of Technology

The oxyfuel group – main methodologies

• Experiments

– 100 kW Chalmers oxyfuel unit – Vattenfall 30 W Schwartze pumpe pilot plant – To come: CFB test unit in Tampere

• Modeling

– Reaction kinetics etc – CFD simulations

• Process simulations

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Procedure

• Scale up effects from the Chalmers 100 kW unit to the

30 MW pilot plant (Schwartze Pumpe)

• Scale up to unit of commercial size (“conventional
• xyfuel 25-30% O2 in RFG)
• Innovative oxyfuel boilers with higher O2 in RFG

Change in conditions have implications for in-furnace processes as well as downstream processes which in turn yield differences in optimal combination of primary and secondary flue gas cleaning measures

Chalmers University of Technology

Chalmers 100 kW oxyfuel test unit

100kW Lignite flame 100kW Lignite flame 27% oxygen 27% oxygen

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Test unit and measurements

C3H8 O2

air/O2/CO2 fan mixing point O2/flue gas Wet flue gas recycle Dry flue gas recycle Flue gas cooler Flue gas condenser Air inlet Stack gas

pre-heater

Fabric Filter Dry, pressurized flue gas for dust control and fuel carrier gas Dry, pressurized flue gas as carrier gas Coal from pneumatic feed system Coal feed

Measurements:

Radiation intensity Gas temperature Gas composition

Chalmers University of Technology

Measurements

A A

1900 mm 200mm Cooling water outlet Cooling water inlet Suction inlet flue gas: D=6mm Thermocouple Type B: D=3mm Section A-A Ø45,0/41,0mm Ø30,0/26,0mm Ø17,2/13,0mm 10,0x1,0 mm Ø13,0mm

• Gas concentration profiles:

Online analysis: O2, CO, HC, CO2, NOx, (SO2)

• Temperature profiles:

suction pyrometer TC: S and B (~2000K)

• Radiation intensity profiles:

Narrow angle radiometer Line-of-sight intensity

Cooling water inlet

A A

1620 mm Cooling water outlet Heated tube: to prevent condensation Gas suction tube 4 mm Section A-A Ø45,0/41,0mm Ø33,0/29,0mm Ø18,0/14,0mm Ø8,0/6,0 mm Thermopile PT-100 Cooling water Collimating tube Cooling water Electronic shutter High broadband reflectance mirror

Experimental set-up

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Nitrogen

• xides

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NOx in oxy-fuel combustion

Principle changes: Concentration of N2 Recycle of flue gas Concentration of combustion products Residence time Temperature

O2 COAL RECYCLE

NOx

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HTNR vs. Reburning

NOin = 1000ppm N2in = 0% O2/CO2 t = 1 s # = 0.9 No Fuel-N

Reverse Zeldovich Reburning

NOx

Figure: Normann. F, Andersson, K, Leckner, B, Johnsson, F, Fuel 87 (2008) 3579–3585, 2008

Chalmers University of Technology

NOx reduction options in oxy-fuel combustion

Advantages Disadvantages NOx red.

Primary Measures

Reburning Proven technology Natural gas consumption 50-60%a Staging Proven technology Reduced combustion efficiency 10-40%a Low-NOx burner Proven technology Reduced combustion efficiency 20-60%a Flue gas recycling Included in the oxy-fuel process ~70%b High-Temp. Improved combustion efficiency/new boiler Melting of ashes/new boiler

• 90%c

Secondary Measures

SCR Proven technology Catalysts/ammonia cons./units 80-95%a SNCR Proven technology Ammonia consumption/slip 30-50%a Lead Chamber/NO2 absorption Simultaneous removal of SOx Extra units

• 90% c

Placed in high-pressure part Waste; weak nitric acid Co-storage Included in the oxy-fuel process Pollution of the CO2

• 95% c

Distillation Simultaneous removal of SOx Power consumption

• 95% c

NOx

Chalmers University of Technology

Summary - NOx

NOx

Several techniques available to reduce NOx in oxy-fuel combustion Reduction via secondary measures may not be required The formation and reduction mechanisms should be investigated further to allow optimization of primary/secondary measures

both high and low NOx levels at the furnace exit may be of interest

The NOx formation in industrial scale oxy-fuel burners need to be studied and compared against results in lab-scale units

Chalmers University of Technology

Radiative heat transfer

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Radiative heat transfer of major importance in design of furnaces Changed combustion conditions will affect the gaseous radiation

Longer pressure path lengths Longer pressure path lengths Different ratio of H Different ratio of H2

2O/CO

O/CO2

2

Radiation

influence of increased gas radiation when it competes with particle radiation? Gas vs. particle radiation in propane and lignite flames

Chalmers University of Technology Chalmers University of Technology

Models tested: SNBM, WSGG smith, WSGG opt. 3+1 Propane flame: Port 3, 384mm from burner

Energy & Fuels; 2008; 22(3); 1535-1541. DOI: 10.1021/ef7004942

Radiation

Propane Propane, Air , Air Propane Propane, OF 21 , OF 21 Propane Propane, OF 27 , OF 27

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Lignite/air flame Lignite/OF 27 flame

Radiation

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Port 3: Air and OF 25

Measured total intensity Modeled gas, particle and total intensity (incl. overlap)

Experimental Thermal and Fluid Science (2008), doi: 10.1016/j.expthermflusci.2008.07.010

Radiation

Chalmers University of Technology

Summary - radiation

Radiation

100 kW experiments: particle radiation completely dominates the radiation in lignite-fired oxy-fuel flames with similar temperature conditions as in air

However, no data is available for industrial scale burners industrial scale burners low/high oxygen fractions low/high oxygen fractions wet recycling conditions wet recycling conditions Gas radiation model has been developed, optimized for CFD But, particle radiation modelling requires significant improvements and experimental validation for use in combustion/heat transfer calculations Industrial scale experiments are essential in further development due to the geometric dependence of radiation

Chalmers University of Technology

Reference flames

Pilot flame outlet Main jet outlet Central fuel jet, Ø 3.6 mm Annular shroud, Ø 60 mm Bluff body face, Ø 50 mm

Sandia Flame D!– Jet!flame SM1!– Swirling flame Chalmers 100 kW unit

• Reynolds Stress Model for swirling

flame

• Eddy Dissipation model better than

EDC when using two-step reaction mechanism

• Reasonable results but deficiencies

in Oxy-fuel combustion

• Radiation models to be improved

(gas radiation, soot and fuel particles)

CFD simulations

Chalmers University of Technology

Chemical looping combustion (Prof Anders Lyngfelt)

Chalmers University of Technology

Fluidized-bed reactor concepts – Experiences at Chalmers

BFBC – Bubbling Fluidized Bed Combustor CFBC – Circulating Fluidized Bed Combustor CFBC-IG – Circulating Fluidized Combustor with Integrated Gasification CLC – Chemical Looping Combustor CLR – Chemical Looping Reformer

Chalmers University of Technology

Chalmers University of Technology

Chalmers University of Technology

CLC results, solid fuel

• The design was verified in terms of particle fluidization and

circulation between the reactors during more than 200 h circulation of particles at high temperatures (above 800°C).

• No agglomeration was found during the testing itself and ilmenite

appeared to be a suitable material (mechanical properties, low cost)

• Operational difficulties were always associated with “external”

problems such as the fuel feeding, loss of fluidization gas, data acquisition etc, and never with the process as such.

• Carbon capture efficiency of up to 91.4%
• CO2 capture varied between 82.5 and 96%
• Poor fuel conversion (poor performance of the fuel reactor cyclone)

Chalmers University of Technology

Summary

• Strong and fast development in CO2 capture area –

scale up process

• Oxyfuel

– Complex flame – two-phase flow-reaction system – Heat transfer (radiation), Chemistry and mixing – Primary vs secondary measures of flue gas control – Second generation oxyfuel plants – increased oxygen concentrations

• Chemical looping combustion

– Development of oxygen carrier – Solid fuel combustion – reduce carbon loss – New concepts