0.5 MWth cycloid fired test rig

of the Chair of Powerplant technologies

of the Brandenburgische Technische

Universität Cottbus

Oxyfuel - Process

Universität Cottbus

Dipl.-Ing. H. Kaß, Prof. Dr.-Ing. H. J. Krautz

Brandenburgische Technische Universität Cottbus

Göteborg, 17. September 2008

Overview Test Rig

Process Flow Chart

Test Rig

Cyclone

Fuel feeding system

FGCFurnace

Boiler

Components and Specifications II

Combustion Chamber (Tangential Fired):• Fuel: Lausitzer dry lignite, x = 0 … 6,3 mm

Polish hard coal, x = 0 … 2 mm

• Thermal power: 0.5 MW

• Average temperature: 950 – 1.000 °C

• Primary air inlet

• 3 secondary air inlets

• 200 kW start-up liquid-gas burner• 200 kW start-up liquid-gas burner

Components and Specifications III

Oxygen and Carbondioxide Supply Unit

• Average O2 usage = 110 – 130 kg/h

• Individual O2 – Concentration in each air level

• max. O2 – Concentration = 24 Vol.-%

• CO2 is used for the jet-impulse of the filter and cooling of the start up-burnerburner

Components and Specifications V

Heat Exchanger:• Heat capacity = 600 kW

• Max. temp cooling water = 110 °C

Cyclone and Ash Cooling Screw:• Capacity = 450 kg/h

• Max. temp = 950 °C

• Min. temp = 40 °C

• Max. temp cooling water = 110 °C

• Max. pressure cooling water = 6 bar

• Max. temp flue gas = 250 °C

Bag-House Filter:• External heated to 250 °C

• Max. temp flue gas = 250 °C

• Max. particle charge = 10 mg/Nm³

• Filter material: PTFE

Components and Specifications VII

Flue Gas Condenser :• 1. Stage: Flue Gas Quench

• 2. Stage: Flue Gas Cooling

• 3. Stage: Process-water Caption

• Flue Gas Capacity = 450 kg/h

• Max. Temp Flue Gas = 250 °C

• Min. Temp Flue Gas = 40 °C

• Process-water recycling

• pH-Value and Conductivity control

R & D - Project

Combustion of Lignite with the Oxyfuel Process

• Duration R & D - Project: 2 years, beginning in December 2006

• Aim: get confirmed process and operation conditions for 30 MW

Oxyfuel - Pilot Plant in Schwarze Pumpe

• Four main topics will be analysed:

1. Verification of the functionality of the test rig

2. Optimisation of the process parameters2. Optimisation of the process parameters

3. Analyses of the behaviour of the combustion and emissions

4. Demonstration Trial (300 h)

Fuel and Flue-gas:

• High Input of heat due to recirculated Flue-gas (up to 102 kW in Oxyfuel-

Operation) reduces the load of the adiabatic combustor (FL/RG-Operation = 27

kW).

• recirculated Flue-gas flow 1.100 kg/h

Massflow Oxygen:Massflow Oxygen:

Flue-Gas

• OZ 1: O2 = 3 ... 4 Vol.-% (125 – 129 kg/h O2)

• OZ 2: O2 = 7 ... 8 Vol.-% (127 – 136 kg/h O2)

• OZ 3: O2 = 10 ... 11 Vol.-% (143 – 150 kg/h O2)

In Front of Furnace

• OZ 1: O2 = 19,2 Vol.-%

• OZ 2: O2 = 21,9 Vol.-%

• OZ 3: O2 = 24,2 Vol.-%

Latest results

• Stable operating conditions at different process-parameters

• CO2-concentration of 92,1 Vol.-% in dry flue-gas

• Reduction of the moisture content from 30 to 5,3 Vol.-% after FCG

• Average Flue gas (dry) composition:

O2 [Vol.-%, dry] 4,81

CO2 [Vol.-%, dry] 88,72

NO (korr. 7% O2) [mg/Nm³, dry] 325,63NO (korr. 7% O2) [mg/Nm³, dry] 325,63

CO (korr. 7% O2) [mg/Nm³, dry] 72,83

SO2 (7% O2) [mg/Nm³, dry] 3235,55

N2O [mg/Nm³, dry] 4,31

Rest N2 [Vol.-%, dry] 6,36moisture Content [Vol.-%] 28,65

Pressure before stack [mbar] 0,04Massflow FG to stack [kg/h] 369,16Temp FG to stack [°C] 181,44dusk content [mg/Nm³] not mesured

NO = f(O2 PL/SL1) mit O 2 nach Brennkammer = 7-8 Vol.-%

0,20

0,40

0,60

0,80

1,00

1,20

1,40

1,60

1,80

2,00

Vol

.-%

O2

in P

L /V

ol.-

% O

2 in

SL1

NO [mg/MJ]

• Different O2-Concentration in Primary

Air Inlet and Secondary Air Inlet at

constant O2-Excess

• Decrease of NO-Concentration by

Staged Combustion < 1

Flue-Gas Composition:

0,0030 35 40 45 50 55 60 65 70 75

NO [mg/MJ]

Staged Combustion < 1

• Staged Combustion < 1 real

flameless Combustion

• Minimum-O2 Concentration in

PL = 14,3 Vol.-%, tr.

NO = f (Sauerstoffzahl), für verschiedene Luftstufungen

0

200

400

600

800

1.000

1.200

1.400

1.600

1,00 1,10 1,20 1,30 1,40 1,50 1,60 1,70 1,80

Sauerstoffzahl

NO

- K

onze

ntra

tion

[mg/

Nm

³, 7

% O

2] Luftstufung = 1

Luftstufung < 1

Luftstufung > 1

Flammenbilder Oxyfuel

O2 nach BK = 10 Vol.-%λ = 1,64

O2 nach BK = 8 Vol.-% ,λ = 1,48

O2 nach BK = 3 Vol.-% ,λ = 1,12

Flue Gas Condenser

• Reduction of the Flue Gas Humidity from 30,5 to 5,3 Vol.-%(ca. 37 kg/h Condensate)

• Cool down of the Flue Gas from 200,5°C to 37,2°C

• Temperatures of the Flue Gas,

Feuchtigkeit nach Kondensator [Ma.-%]

2,0

4,0

6,0

8,0

10,0

12,0

Feu

chtig

keit

RG

[Ma.

-%]

H2O nach Kondensator [Ma.-%]

SO2= f(pH-Wert) ohne NaOH

0,0

2,0

4,0

6,0

8,0

10,0

12,0

14,0

15:20 15:25 15:30 15:35 15:40 15:45 15:50

Zeit [hh:mm]

pH-W

ert,

Leitf

ähig

keit

0

1.000

2.000

3.000

4.000

5.000

6.000

7.000S

O2

[mg/

Nm

³]pH-Wert

Leitfähigkeit [mS/cm²]

SO2 [mg/Nm³]

Kondensator in Betrieb

• Temperatures of the Flue Gas, Condensate and Cooling Water are nearly the same

• Neutralisation of the Condensats with NaOH (30 %)

• High SO2-Reduction in the FGC • SO2-Reduction is a function of pH-

Value

0,030,0 35,0 40,0 45,0 50,0 55,0 60,0 65,0

Temperatur RG nach Kondensator[°C]

Rauchgaskondensator SO 2 n Kondensator = f(pH)

3.000

4.000

5.000

6.000

[mg/

Nm

³]

SO2 nach Kondensator

0

1.000

2.000

3.000

3,0 3,5 4,0 4,5 5,0 5,5 6,0 6,5 7,0

pH-Wert [-]

SO

2 [m

g/N

m³]

Oxyfuel Flame

Thank you