Prof. Dr. techn. G. Scheffknecht

Institute of Combustion and Power Plant Technology

Design and Commissioning of a 200 kWthth

Calcium Looping Pilot Plant 

Craig HawthornegHawthorne@ifk.uni‐stuttgart.de

Co‐authors: H Dieter A Bidwe M Zieba G ScheffknechtCo‐authors: H. Dieter, A. Bidwe, M. Zieba, G. Scheffknecht

High Temperature Solid Looping Cycles IEA‐GHG 2nd Network Meeting

September 16‐17, 2010

Calcium Looping Process

CO2 capture from power plant flue gasesElectricity generation from excess heatElectricity generation from excess heatFurther utilization of spent sorbents

Calcium Looping Pilot Plant Overview

Pilot Plant Objectives: Next step in Calcium Looping development

Specific Design Requirements

200 kW equivalent flue gas asCalcium Looping development

Demonstrate Calcium Looping as an integrated process on a pilot scale i h %

200 kWth equivalent flue gas as carbonator input

Real or synthetic flue gaswith over 90% CO2 capture

Temperatures controlled through fuel combustion or removal of 

Facility to run continuously for 1 week with continuous make‐up addition

Oxyfuel regnerator with O stagingprocess heat

Long‐term sorbent behaviour under real operating conditions

Oxyfuel regnerator with O2‐staging

Stable hydrodynamic dual fluidized bedea ope a g co d o s

Attrition and chemical deactivation

Effect of fuel sulphur and ash in regenerator

Control and optimize following parameters wrt CO2 capture:

Calcium looping ratioregenerator

Effect of oxyfuel regeneration

Process optimization 

Calcium looping ratio

Make‐up ratio

Bed inventory (Space Time)

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Data collection  scale‐up to demonstration facility

Carbonator temperature

Regenerator temperature

Basic      Design

Instrumentation      & Control

Plant Engineering      &  Construction

Pilot Plant Commissioningg g

CO2‐rich GasCO2‐lean Flue Gas

Pilot Plant Designed Operating Range

Parameter Symbol Unit Min Max

Carbonator RegeneratorCaCO3

Carbonator Flue Gas Thermal Input

Pth kWth 170 230

Carbonator Temp TCarb °C 600 700

CaO

Carbonator Temp TCarb C 600 700

Regenerator Temp TReg °C 850 950

Regenerator Inlet O2 CO2 vol.‐% 21 65 CaO

Velocity (Carb / Reg) U m/s 4 7

Carb / Reg Height h m 10

(FCa)CaCO3

(FCa)

Oxidant Ca Looping Ratio FCa/FCO2 ‐‐ 4 14

Make‐up Ratio F0/FCO2 ‐‐ 0 0.3Fuel

Staging

Flue Gas

(FCO2) O2 + CO2

Fuel

Make‐up (F0)Solid Looping Rate controlled by cone valves

Basic      Design

Instrumentation      & Control

Plant Engineering      &  Construction

Pilot Plant Commissioning

Flue Gas ID Fan

g g

FilterFilterAsh/Dust

DustFilter

Gas CoolerQuenchGas Cooler asGas CoolerQuench

CaO / CaCO CaO

Gas Cooler

cula

tion

G

Cyclone

Solid

CycloneCaCO3

CaO

Solid

Cyclone

Rec

irc

ValveCarbonator Regenerator

Fuel

Limestone

ValveCombustor

Fuel

Purge

AirO2/CO2 O2

Basic      Design

Instrumentation      & Control

Plant Engineering      &  Construction

Pilot Plant Commissioning

Gas Supply

g g

Supply of reactor fluidization gas by  high pressure blowers

Regenerator oxyfuel O addition withRegenerator oxyfuel O2 addition with MFC‘s:  flexible primary, secondary, tertiary oxidant addition

Loopseal fluidization with MFC‘s (CO2, O2, Air, N2)

Solids Supply and Withdrawl Systems

Feeding system for limestone and fuelCoalCoal

Biomass or other fuel mixtures

Automatic solids removal with lock h

6

hopper system

Basic      Design

Instrumentation      & Control

Plant Engineering      &  Construction

Pilot Plant Commissioningg g

REACTORS

Gas- / Solid Measurement

Return Leg

Heat Transfer- / Corrosion Ports

Secondary Air

Pressure Ports

(Temperature ports on reverse side)on reverse side)

Basic      Design

Instrumentation      & Control

Plant Engineering      &  Construction

Pilot Plant Commissioning

Process Cooling & Cleaning

g g

Heat removed from reactors with Bayonet coolers

Exhaust gases are cooled to desiredExhaust gases are cooled to desired temperatures by gas coolers or a quench

Gases are dedusted in bag filter before going to ID fan or being recirculated 

i h il lHeating Up the Pilot Plant

Excess air burner used to control temperature and rate of heating up for p g pall 3 reactor trains 

Flue Gas Generator

Carbonator

8

Carbonator

Regenerator

Basic      Design

Instrumentation      & Control

Plant Engineering      &  Construction

Pilot Plant Commissioning

Cooling System

g g

Fuel & Limestone Feeding

Cooling System ID Fan

Feeding

Gas cooler

Cyclone

Flue gasR t

Gas coolerBag Filter

ggenerator Regenerator

Carbonator

Excess Air Burner

CarbonatorI/O Box

for Start Up Carbonator Preheater

Purge Removal

Basic      Design

Instrumentation      & Control

Plant Engineering      &  Construction

Pilot Plant Commissioning

Process Control System

Pil l i f ll d i h f

g g

Pilot plant is fully automated with safety interlocks

2 work stations & 1 plant monitoring station p g

Over 40 control loops & 10 safety control loops

Devices (some of them)

Fuel & limestone metering systems (plus re‐Fuel & limestone metering systems (plus refill)

High pressure gas blowers (recirculated flue )gas)

Gas control valves – pressure or temperature

Cone valve for automatic Calcium Looping

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Cone valve for automatic Calcium Looping Ratio control

Basic      Design

Instrumentation      & Control

Plant Engineering      &  Construction

Pilot Plant Commissioning

Temperature

O 75

g g

Over 75 temperature measurements

Carbonator &  Regenerator fully characterized

PressurePressure

Over 55 pressure transducers :Reactor modelling

CFB optimization

Flow

Gas flows are measured in and out of everyGas flows are measured in and out of every reactor 

Close the CO2 mass balance and accurately CO t ffi imeasure CO2 capture efficiency

Solid flowsEvery solid loop has a physical flow 

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y p p ymeasurement unit

Online solid flow measurement

Basic      Design

Instrumentation      & Control

Plant Engineering      &  Construction

Pilot Plant Commissioning

Gas Sampling & Measurement

O b O

g g

Oxygen probes measure wet O2‐conc.  to control combustion performance

4 online gas analyzer cabinets:g yFlue gas: O2, CO, CO2, SO2

Sub‐stoichiometric combustion: H2, CH4, CO CO O hydrocarbons (GC)CO, CO2, O2, hydrocarbons (GC). 

Custom probes for measuring CO2concentration in carbonator 

Reactor modelling with pressure profiles

Solid Sampling & Measurement

Solids sample ports in every stream

Fast lab analysis of carbonated fraction (X b)

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(Xcarb)

Fast lab analysis of maximum conversion (Xmax).

Basic      Design

Instrumentation      & Control

Plant Engineering      &  Construction

Pilot Plant Commissioningg g

Hot Commissioning Finished

h dReactor trains heated up to process temperature to treat refractory for 96 h

Cooling system commissionedand optimized

Flue gas cooling optimized Increasing CarbonatorFlue gas cooling optimized

DFB Operated at Ambient Temperature with Limestone

Increasing CarbonatorInventory

Temperature with Limestone

System is stabile and fulfills design specifications

Desired bed inventory achieved

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Basic      Design

Instrumentation      & Control

Plant Engineering      &  Construction

Pilot Plant Commissioningg g

DFB Operated at Ambient Temperature with LimestoneTemperature with Limestone

System is stabile and fulfills design specifications

Design WindowDesired bed inventory achieved

Required range of Calcium

Design Window

Required range of Calcium Looping ratios acheived

Upcoming WorkUpcoming Work

Calcium Looping pilot plant testing in September & October

Baseline testing of long‐term sorbent 

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performance

Acknowledgements

The design, construction and operation of the Calciumoperation of the Calcium Looping pilot plant at IFK, 

University of Stuttgart is funded by

EnBW Kraftwerke AG 

as part ofas part of 

a joint university‐industrial 

research & development project

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