pressurized steam fluidized bed drying (psfbd) of lignite ... · why to pre-dry lignite in a...

Brandenburg University of Technology Cottbus - Senftenberg, Chair of Power Plant Technology

www.b-tu.de/fg-kraftwerkstechnik Berlin | 9th Freiberg Conference | 05.06.2018

Pressurized Steam Fluidized Bed

Drying (PSFBD) of Lignite - State of

the Development and selected

Results of 15 Years R&D

9th International Freiberg Conference on IGCC & XtL Technologies

Berlin, 05.06.2018

Matthias Merzsch, Dr. Matthias Klatt, Prof. Hans Joachim Krautz

Chair of Power Plant Technology, BTU Cottbus – Senftenberg

Dr. Olaf Höhne

LEAG - Lausitz Energie Kraftwerke AG


www.b-tu.de/fg-kraftwerkstechnik Berlin | 9th Freiberg Conference | 05.06.2018 2

Brief introduction

PSFBD Facilities

Development activities

Outlook

Table of Contents

Cottbus

Berlin



57%

3%

23%

17%

Lusatian processing coal (raw)

3

Why to Dry Lignite?

raw

w=19%

9.2

19

0

5

10

15

20

raw w=19%

9.2

19

05

101520

raw w=19%

Net calorific Value [MJ/kg]

Proximate analysis of Lusatian processing coal

2 Lusatian lignite briquettes

(w=19%, 1.15 kg)

evaporated water from

raw lignite (0.967 kg)

water remaining in

briquettes (0.219 kg)



Why to Pre-Dry Lignite in a (Pressurized) Steam Fluidized Bed?

4

Schematic diagram of the PSFBD process

Increasing the efficiency by up to 5 percentage

points in lignite fired power plants (44% 49%)

Drying with heating steam at low temperature in

place of hot flue gases

use of vaporized lignite water energy

more intensive heat & material transmission in

contrast to conventional tube dryers

(upgrading/processing facilities)

Up to 80% less energy consumption

Precondition for CCS technologies in power plants



Industrial Park Schwarze Pumpe – Lausitz Energie Kraftwerke AG

Raw lignite throughput < 550 kg/h

commissioning 2003

BTU Cottbus-Senftenberg – Chair of Power Plant Technology

PSFBD Facilities

Raw lignite throughput 8…10 t/h

commissioning 2008



PSFBD Facilities - development activities

rotary feeder

•Test of different Manufacturers and different sealing

methods (conical rotor, sealing faces, minimum gap)

Reduction of leakage steam by 75% compared

with commissioning

5-10% losses of vapor by leakage

• High moister of raw lignite in combination with the small particle size

• Minimize the leakage steam of the pressurized vessel (efficiency,

particle moisture)

20

30

40

50

60

70

80

0 10 20 30 40 50 60

rep

os

e a

ng

les

φ[

]

water content [% total mass]

Lusatian processing coal 0-2 mm

Central german processing coal 0-2 mm

Challange:

φ




1. Change over to a finer grained lignite

(0-6 mm 0-2 mm)

2. Installation of a dust recirculation

(average particle diameter ↓, average moisture ↓)

0

100

200

300

400

500

600

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80

he

at tr

an

sfe

r c

oe

ffic

ien

t h

[W

/(m

²K)]

fluidization velocity [m/s]

0-2 mm 0-3 mm

0-4 mm 0-6 mm

0

100

200

300

400

500

600

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40

he

at tr

an

sfe

r c

oe

ffic

ien

t h

[W

/(m

²K)]

fluidization velocity [m/s]

0-2 mm

0.02-2 mm

0.04-2 mm

performance improvement (fluidized bed heat transfer /

0

100

200

300

400

500

600

0 10 20 30 40 50 60

ma

xim

um

he

at tr

an

sfe

r c

oe

ffic

ien

t h

ma

x[W

/(m

² K

)]

water content [% total mass]

0-2 mm

0-3 mm

0-6 mm

process stability)




design improvement (fluidized bed heat transfer / tube bundle)

0

100

200

300

400

500

600

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40

he

at tr

an

sfe

r c

oe

ffic

ien

t h

[W

/(m

²K)]

fluidization velocity u [m/s]

tube diameter = 14 mm

tube diameter = 21.3 mm

tube diameter = 33.7 mm

0

10

20

30

40

50

0 20 40 60 80 100

vo

lum

e-r

ela

ted

he

at tr

an

sfe

r [k

W/m

³K]

packing density [m²/m³]




3. Detailed investigation of different

heat tube bundle geometries

(tube diameter,

tube arrangement & pitch)

zy

x

sh

sv

c)

sh

sv

b)

sh

sv

a)

But: stability criteria for higher moisture contents??




Fluidizing stability

Reduction Fluidization blower power of 50%

Minimizing of dust discharge

10 0.1 0.4 0.5 0.4 0.5 0.7 0.5 0.3

9 0.4 0.8 1.8 1.4 1.2 1.8 0.7 0.4

8 1.3 1.6 3.7 2.7 2.1 2.9 1.7 0.8

7 2.3 1.2 2.7 2.9 1.7 2.6 1.7 2.1

6 1.3 0.6 0.7 1.1 1.1 0.8 0.6 1.2

5 2.0 1.1 1.5 1.4 0.7 0.6 0.6 1.3

4 2.9 2.8 3.4 1.3 1.4 2.6 1.6 1.9

3 1.0 1.6 2.4 1.5 1.5 3.2 1.9 0.6

2 0.1 0.3 0.8 0.9 1.0 1.4 0.3 0.1

1 0.0 0.1 0.3 0.3 0.2 0.2 0.1 0.0

A B C D E F G H

10 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

9 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

7 0.0 0.0 0.0 1.3 0.8 0.0 0.0 0.0

6 0.0 0.0 6.4 20 22 2.1 0.0 0.0

5 0.0 0.1 5.8 18 22 1.3 0.0 0.0

4 0.0 0.0 0.1 0.3 0.3 0.1 0.0 0.0

3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

A B C D E F G H

4. Raw lignite distribution

from laboratory investigation

to industrial application

wit

ho

ut

dis

tru

bu

tor

wit

h o

pti

miz

ed

dis

tru

bu

tor




Pressurizing and technology extension

5. Increasing heat transfer rates and efficiency

through pressurizing

400

420

440

460

480

500

520

540

560

1 1.5 2 2.5 3 3.5 4 4.5

ove

rall h

ea

t tr

an

sfe

r c

oe

ffic

ien

t [W

/m²K

]

system pressure [bar abs.]

PSFBD - Schwarze Pumpe

successful installation and testing of a

steam converter and a steam recompression plant

LEAG – Schwarze Pumpe





Pressurizing and technology extension



Re-use of 90% of the vaporized lignite water

Reduction of 65…80% thermal energy demand

Reduction of 40…50% primary energy demand (Electrical energy demand compressor)




further R&D activities

155

156

157

158

159

160

161

162

163

164

165

0

1

2

3

4

5

6

7

8

9

10

16:20 16:30 16:40 16:50 17:00 17:10 17:20 17:30 17:40

Kü

hlw

asse

rte

mp

erat

ur

[°C

]

Tem

pe

ratu

rdif

fere

nz

Sat

tdam

pf -

Ro

hrw

and

[K

]

Temperaturdifferenzen in Messstrecke Dampf - Rohrwand

T_39 (-30°) T_36 (+60°) T_37 (-120°) T_38 (+150°) T_KW

-120

-30

150

60

-30

-120 150

60

-30

-120 150

60

-30

-120 150

60

5,6

0 m

0

200

400

600

800

1.000

1.200

1.400

1.600

1.800

5 6 7 8 9 10 11 12 13 14 15 16

dif

fere

nti

elle

Bin

du

ng

sw

ärm

e

[kJ

/kg

W]

Wassergehalt [Ma.-%]

1,0 bar

1,5 bar

2,0 bar

3,0 bar

4,0 bar

6,0 bar

Fundamental research – heat of binding at preassures up to 6 bar

numerical modeling of hydrodynamics

and heat/mass transfer

Process integration – thermal schematic calculations

Experimental investigation of condensation in horizontal pipes

at pressures up to 10 bar (heat transfer & pressure drop)



Outlook

PSFBD as prestage for further lignite refinement

(e.g. activated carbon production for mercury

capture from stack gas of power plants)

Further optimization of the dryer design

(performance increase by innovative pipe structures)

PSFBD as Retrofit for existing power plants

(depends on political circumstances)



Many thanks for your attention!

Dipl.- Ing. (FH) Matthias Merzsch

Chair of Power Plant Technology

Brandenburg University of Technology Cottbus – Senftenberg

Telefon: +49 (0) 355 69 4007

E-Mail: [email protected]

pressurized steam fluidized bed drying (psfbd) of lignite ... · why to pre-dry lignite in a...

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