Oxy-fuel combustion integrated with a CO2

processing unit

POLISH STRATEGIC PROGRAM

„ADVANCED TECHNOLOGIES FOR ENERGY GENERATION”

coordinator: Wojciech Nowak

AGH University of Science and Technology

Kraków, Poland

Ryszard Białecki

Silesian University of Technology

Gliwice, Poland

D e t a i l e d o b j e c t i v e s

To recommend one out of three coal burning technologies (PC, CFB, PCFB) best fitting for oxy-combustion technology.

To evaluate modernization possibility of current power system by retrofitting operating/exploited units for oxy-combustion.

To indicate development directions of clean coal technologies in Poland.

To reach technological readiness to demonstrate industrial scale power unit equipped with oxy-combustion boiler integrated with CO2 sequestration.

Wrocław University of Technology

Silesian University of Technology

Częstochowa University of Technology

Institute for Chemical Processing of Coal

Tauron - Power Station Łaziska

Wrocław University of Technology

PGE - Power Station Power Station Turów

Foster Wheeler Energia, boiler manufacturer

Eurol Innovative Technologies (SME)

Institute of Power Engineering

2000-2015, budget €22M

ignition, pollutants, interaction with ash, comparison of different fuels

Combustion of single coal particle: normal and increased pressure Selected findings

• ignition time in air shorter than in oxy

• stable conditions of ignition in a laminar flow reached 536°C for coal and 520°C for lignite

• lower emission in oxy-combustion

• lower unburned content in oxy mode

• co-firing may be beneficial

• stabilized ignition when cofiring

• deposition rate of ash in oxy twice higher than that of air

• oxy atmosphere lowers the ash sintering temperature

`

O2 CO2

MSC

Patent pending

P. 411669: System for

CO2 capture in oxy-combustion of solid fuels in circulating

fluidized bed boilers

Exp

erim

ents

Measurements (flue gases concentrations time courses)

13 main flue gas components

In-furnace sampling @ 4 levels

Integration

Oxy-Fuel CFB Combustor

VPSA-CO2

Unit

Factor Recommendations

O2 con. 30%-vol. or higher

O2 exc. between 5% - 15%

Temp. ca. 850oC

PG/SG insignificant impact

Range of investigations

Localization of measurement probes in the boiler design stage

Samples of boiler steel

Corrosion tests – 154 MWth CFB boiler

X8CrNi HR6W

Continuous transition from air to oxy-combustion

► the range of investigations: - pressure (0-8 bar) - O2 fraction in oxidizer (up to 35%-vol.)

► tests on PCFB 0,2 MW NOX and SO2 emission

Pilot PCFB 0,2 MWth unit

Pressure 5 bar O2/CO2 = 30/70 reduction of emission compared to air o 50% reduction of SO2 o 70% reduction in NOx

Pilot scale tests on 0,5 MW PC – Power Engineering Institute, Warsaw

► O2/CO2 atmosphere reduces combustion temperature if O2 fraction <27%-vol

► Combustion time in O2/CO2 shorter if O2 > 21%-vol.

► Wet recirculation rises temperature and shortens combustion time

► Flue gas recirculation of RR=74% (heat exchange)

► Oxy-combustion reduces NOx emission (by about 25%)

► Oxy-combustion shortens the burn-out time of pulverized coal (by about 30-50 %) allows combustion of coarser coal particles lower costs of fuel preparation higher net efficiency of power unit

Two designes of vortex burners fitted for oxy-combustion, both for retrofitted and new boilers

Patent pending: Method and burner for combustion of pulverized

coal in concentrated oxygen flux

experiments using Laser Induced Fluorescence

Patent pending Method of granulate production, especially perovskite structure compounds in thermal decomposition process of metal compounds with use of Spray-pyrolysis apparatus with inner air heating system.

Membrane processes

Patent pending Method of oxygen separation out of air with use of perovskire collar-less pipe membranes

PSA technology on zeolite bed

Mobile installation for oxygen separation VPSA-O2

Adsorber, station valve and measuring system

► Pilot installation: - output: 100 m3

N/h - oxygen purity: 95% - vol. - sorbents: zeolite molecular sieve, active Al2O3

Four-bed V-PSA installation Two-bed PSA installation Mobile four-bed DR-VPSA installation

Integrated VR model

► identification of technical and economical risk factors ►risk evaluation connected with oxy-combustion power unit choice

► Thermodynamic analysis allowed for optimisation of oxy-combustion power unit

Patent pending: Method of solid fuels drying

quality improvement especially in power

plant using oxy-combustion”

Patent pending: Method of technical gasses

compression, especially carbon dioxide”

Final aftercooling of carbon dioxide with the use of absorption heat pump system

Patent pending: Method of final after cooling of carbon dioxide with the use of

absorption heat pump system

Model of the separation

adaptation of air furnace to oxygen without introducing changes in heating surfaces possible

flue gas recirculation (68-74 %) power rate similar to air mode

Population balance method of fluidized bed materials allowing for operation optimization of CFB boiler systems

► LES and RANS simulation methods

Possibility to apply developed mathematical models to design or adapt oxy-combustion PC and CFB

boilers in industrial scale installations

21% O2/75% CO2 35% O2/65% CO2

Temperature fields in various oxidizing atmospheres - simulation using Large Eddy Simulation method

A mean temperature in O2 = 30% CO2 = 70%

RANS LES

Volume fraction of the solids phase in a CFB combustion chamber

Numerical model of oxy-combustion in CFB boilers

separators

heat transfer surface

primary O2

secondary O2

Sustainable Development Index ratio of cummulative exergy consumption and exergy of products

Sust

ain

able

De

velo

pm

ent

Ind

ex

boiler island

steam cycle

ASU CPU

Technological retrofit concept of power unit with OP-650 PC boiler

coal

mill

boiler

air

flue gases

electro filter

desulphu-risation

coal

mill

boiler

electro filter desulphu

rization

ASU

cooling water

condensate from steam cycle

moisture separation

inerts separation

CO2

O2 N2

► Full concept of retrofitting existing power units for oxy-combustion developed: - simulation models of installation - economic analysis of investment - schedule of implementation - risk estimation

PC 200MW Air Oxy

Water flux in cooler kg/s 8389,3 10793,6

Make-up water flux kg/s 125,84 161,89

Gross power kW 144885 156020

Net power kW 133505 104430

Gross efficiency of power unit % 41.12 42.62

Net efficiency of power unit % 37.91 28.52

Boiler efficiency % 91,50 92,3

Internal load indicator % 7,12 33.07

Flue gas recirculation rate % - - 78.9

Technological retrofit concept of power unit with Ofz-425 CFB boiler

inerts separation

coal + sorbent boiler

air

electro filter

coal + sorbent

boiler

electro filter

ASU O2 N2

cooling water moisture separation

CO2

condensate from steam cycle

Technological retrofit concept of power unit with Ofz-425 CFB boiler

CFB 150MW Air Oxy

Water flux in cooler kg/s 8389,3 10793,6

Make-up water flux kg/s 125,84 161,89

Gross power kW

214089,0

0 214098,00

Net power kW 198828 142203

Gross efficiency of power unit % 38,79 39,67

Net efficiency of power unit % 36,02 26,35

Boiler efficiency % 91,60 92,37

Internal load indicator % 7,12 33,58

Flue gas recirculation rate % - - 80,34

► Full concept of retrofitting existing power units for oxy-combustion developed: - simulation models of installation - economic analysis of investment - schedule of implementation - risk estimation

Location of CO2 capture installation key elements for 30 MWe scale

CFB Turow Power Plant case study

CO2 pipeline routes from PGE Turow Power Plants to geological structures in Kowalowo, Bogdaj and Radnica

- CO2 pipeline project – alternative routes - CO2 pipeline project – option routes -Turow Power Plant - proposed locations of geological structures of CO2 storage - Natura 2000 area

Development of oxy-fuel combustion technology in Poland

Conclusions What do we know? (1)

CO2 quality • tests and numerical simulations confirmed 80%+ CO2 purity without

dedicated CPU system • 99% CO2 purity possible if cryogenic or adsorption CPU system is applied Efficiency penalty & improvements • 10% points efficiency penalty for not integrated plant (air-fired ref.) • reduction to 7% points penalty possible by process integration and waste

heat utilization • further efficiency improvement by waste nitrogen utilization for coal

drying or cooling purposes • low excess oxygen and low NOx operation demonstrated • high steam cycle efficiency makes integration more effective

What do we know? (2)

Implementation perspective • only larger scale projects still going ahead: Callide 100MW (Aus),

FutureGen (USA) 167MW and White Rose (UK) 426MW • China increasing interest • large-scale tests needed for demonstration of integrated oxy-fuel plant

concept • flexible air- and oxy-mode switching possible • CFD studies proved the possibility for oxy-fuel retrofit of existing boilers

What do we know? (3)

Different technological options 5bar CFB pressurized oxy-coal tested » High efficiency » Good fuel flexibility » Retrofit and using existing turbo-machinery possible Oxy-Lignite - great potential for clean combustion » lignite moisture impacts the efficiency » Integrated grinding/dryer » less flue gas, smaller plant » idea for ASU-waste nitrogen use for lignite drying

What do we know? (4) example of optimization results – lignite-fired PC boiler

What do we know? (5) Exemple of optimization results – lignite-fired PC boiler

Case number

Description

1 reference oxy-fired unit 2 30% molar share of oxygen in oxidizer 3 heat recovery from flue gas and compressors intercooling to steam cycle

4 steam-driven compressors in ASU and compression train

5 heat recovery from the flue gas to combustion oxygen

6 lignite drying by preheated waste nitrogen

7 lignite drying by preheated air and waste nitrogen

8 “wet” recirculation of flue gas to boiler 9 partial replacement of CO2 compression by CO2 pumping, made possible by

previous CO2 condensation by water cooled in air-cooled tower 10 partial replacement of CO2 compression by CO2 pumping, made possible by

previous CO2 condensation by water cooled in air-cooled tower and nitrogen-cooled tower

11 combination of the above improvements that results in the highest net electrical efficiency of the power unit

What do we know? (6) Example of optimization results – lignite-fired PC boiler

Air-fired reference: 43,78 %