Ongoing work within the Mechanical Engineering Department,Imperial College, London

Mathieu Lucquiaud, Hannah Chalmers, Jon Gibbins

UKCCSC meeting,

Nottingham University,

18/04/2007

INTRODUCTION

• The first generation of full-scale CCS plants is likely going to be built within the next 5-10 years worldwide.

• The EU has announced indicative targets : 12 CCS plants before 2015, CCS becomes routine by 2020.

• Some of these plants will be built in the UK and will start to operate with capture by 2011-2012

• But most plants to be built worldwide before 2020 will operate for a significant part of their life without CCS.

• Some answers to the issues associated with CCS in the power plant industry?

PERFORMANCE OF PULVERISED COAL PLANTS WITH CO2 POST-COMBUSTION CAPTURE (1)

• Reduce the energy penalty associated with CO2 capture• 1/3 of this penalty => CO2 compression• 2/3 of this penalty => Solvent regeneration by taking steam

from the steam turbines• For a power plant user: steam is electricity and electricity is

money

• Better integration of the CO2 capture plant with the turbines/steam cycle is required

PERFORMANCE OF PULVERISED COAL PLANTS WITH CO2 POST-COMBUSTION CAPTURE (2)

• How a tight integration affect the operability of the plant?• For the first generation of CCS plant the operability of the

capture plant is likely to be low during the 1st years of operation

• These plants have to be able to operate without CO2 capture to keep the lights on !!!

• Consequences on plant/turbine/steam cycle design

CAPTURE-READY POWER PLANTS (1)

• Plants which have the ability to include CO2 capture when the necessary regulatory or economic drivers are in place

• Objective: 1. avoid the risk of “stranded” assets for the power

plant industry2. avoid consequent carbon lock-in for society

• Minimal requirements:1. Inclusion of sufficient space and access for the

additional plant2. Identification of a reasonable route towards CO2

storage

=> IEA GHG report on capture-ready power plants to be released in 2007

CAPTURE-READY POWER PLANTS (2)

• For post-combustion capture some pre-investments in the steam cycle can be economically justified and allow to operate the plant:

1. with similar performance to standards units without CCS2. with close performances to new-build CCS units3. with a reduced retrofit time/plant outage 4. without capture after retrofit if required

• Facing the uncertainty of technology developments1.Oxyfuel or post-combustion capture-ready for

pulverised coal power plants2. Design for a solvent with advanced performance but retrofit with post-combustion capture with today available solvent

PART-LOAD PERFORMANCE

• Fossil-fuelled power plants are used to follow electricity seasonal/daily variation.

• Increasing integration of intermittent renewable electricity sources within the grid

• Pulverised coal power plants are likely to be operated more often at part-load in future. Reactivity to electricity demand variation is going to become a key issue.

• No existing data of coal plants with CO2 capture operated at part-load

=> Potential for flexible operation of pulverised coal power plants with CO2 capture, Conference paper to be presented in 2007

ENHANCED FLEXIBILITY with post-combustion capture(1)

• It is possible to improve the value of plants with CO2 capture by delaying/altering the energy penalty associated with post-combustion capture.

• Electricity selling price varies seasonally but also daily. • Selling electricity when people turn their kettles on is highly

profitable!!• Solvent storage/CO2 venting can be used to alter/delay the

energy penalty associated with CO2 capture • It can increase plant electricity output by approximately 20%

when required for post-combustion capture

Initial Assessment of Flexibility of Pulverised Coal Fired Power Plants with CO2 Capture, Conference paper to be presented in 2007

• It is done by by-passing the solvent reboiler and switching off the CO2 compression train for a short period.

• Solvent storage + delayed regeneration has no additional CO2 emissions

• Economic trade-off between solvent storage + delayed regeneration and CO2 venting. Possible additional revenues for power plant users depending on CO2 prices and electricity selling prices.

• Performance when storing/regenerating solvent needs has been partially characterised at Imperial

ENHANCED FLEXIBILITY with post-combustion capture(2)

=> Initial evaluation of the impact of post-combustion capture of carbon dioxide on supercritical pulverised coal power plant part load performance, Fuel, 2007

• Characterise plant performance at part-load and with varying levels of CO2 capture

• Develop model of the post-combustion capture plant=> New DTI project + BCURA (British Coal

Utilisation Research Association) project with Chemical Engineering Department at Imperial College

• Co-combustion of biomass + coal.=> BCURA project

• Develop techno-economic methods to value flexibility of power plants

• CCS deployment option, including in China • => Near Zero Emission in China (NZEC) project

FURTHER WORK within the next 6-12 months

THANK YOU

ANY QUESTIONS?

FLUE GAS COOLER

to stack

ST

RIP

PE

R

SOLVENT REBOILER

SC

RU

BB

ER

Cooling water

Flue gas

solvent

Steam cycle condensate

CO2

Condensate from CO2

CO2 compressed for transport

Steam from turbine island

STORAGE TANK 2

STORAGE TANK 1

turbine island

turbine island

HP LP LP

Spray

IP

Heat Recovery from CO2 Plant

Heat to Solvent Reboiler

Generator

Condenser

Reheater

Boiler

Valve 2

Valve 1