coupling of power generation with syngas-based chemical

Coupling of power generation

with syngas-based chemical synthesis

Clemens Forman, Matthias Gootz, Christian Wolfersdorf, Bernd Meyer

Institute of Energy Process Engineering and Chemical Engineering, TU Bergakademie Freiberg

14th June 2016, Cologne, Germany

Coupling of power generation with syngas-based chemical synthesis

1. Background and motivation

2. Power generation cases

3. Coupling interfaces

4. Modeling results

5. Summary

2

OUTLINE

8th International Freiberg Conference, 12 – 16 June 2016


3

1. BACKGROUND AND MOTIVATION


lignite

coal

gasifier

water

scrubbingCO-shift

CO2/H2S

scrubbing

lignite-fired power plant

650‒1,100 MW(el)

coal

combustionsteam cycle

flue gas path

MeOH

synthesis

MtG synthesis

MtO synthesis

Fischer Tropsch synthesis wax, diesel

gasoline

olefinsentrained-flow (EFG)

fluidized-bed (FBG)

drying

flue gas, ash, gypsum

200MW(th)

small-scale chemical synthesis

carbon

residue

sour

gas

steam

residual

gas

waste water pretreatment CO2

electric

grid

renewable

energy

sources

Annex plant

auxiliaries

water

electrolysis

50 MW(el)

H2

electric energy

O2


Existing power plant Design data Future power plant

built in 1970s to be built 2020+

1,725 MW rated thermal input* 2 x 1,155 MW (30 % dry lignite)

672 t/h coal demand 2 x 450 t/h

650 MW gross electric output 1,100 MW

607 MW net electric output 1,046 MW

37.7 % gross efficiency* 47.6 %

35.2 % net efficiency* 45.3 %

1,853 t/h live steam generation 2 x 1,387 t/h

170 bar; 530 °C live steam parameter 285 bar; 605 °C

34/30 bar; 300/540 °C cold/hot reheat steam 56/51 bar; 340/620 °C

66 mbar condenser pressure 35 mbar

wet cooling tower cooling system hybrid cooling tower(natural draft) (forced draft)

4

2. POWER GENERATION CASES


* thermal input / efficiencies based on LHV


Power plant modeling

Steady-state simulation

Part load performance

5



slidingpressure

pressuredrops

efficiencycurves

steamcycle

heatlosses

auxiliarypower

boilercurves

flue gas path

plantmodeling

Simulation mode

► Existing power plant

Reference case: design

Annex integration: off-design

► Future power plant

Reference case: design

Annex integration: design


Key performance data: net plant efficiency; specific auxiliary power

existing power plant: 50‒100 % load future power plant: 40‒100 % load (per block)

6



4,5

5,0

5,5

6,0

6,5

7,0

7,5

8,0

-3,25

-2,75

-2,25

-1,75

-1,25

-0,75

-0,25

0,25

50 55 60 65 70 75 80 85 90 95 100

spe

cifi

c au

xilia

ry p

ow

er

(%)

net

pla

nt

effi

cie

ncy

ch

ange

(%

-po

ints

)

boiler capacity (%)

net efficiency change

specific auxiliary power

2,5

3,0

3,5

4,0

4,5

5,0

5,5

6,0

6,5

7,0

-4,25

-3,75

-3,25

-2,75

-2,25

-1,75

-1,25

-0,75

-0,25

0,25

40 45 50 55 60 65 70 75 80 85 90 95 100

spe

cifi

c au

xilia

ry p

ow

er

(%)

net

pla

nt

effi

cie

ncy

ch

ange

(%

-po

ints

)

boiler capacity (%)

net efficiency change

specific auxiliary power

0.25

-0.25

-0.75

-1.25

-1.75

-2.25

-2.75

-3.25

0.25

-4.25

-3.75

-3.25

-2.75

-2.25

-1.75

-1.25

-0.75

-0.25

8.0

7.5

7.0

6.5

6.0

5.5

5.0

4.5

7.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5


Existing power plant

Target: coupling interfaces

require little constructional

effort only

► MP steam: injection into

the cold reheat pipeline

► LP steam: installation of

an additional feedwater

heater bypassing the existing

LP feedwater heating section

► Carbon residue & gases:

combustion / thermal treatment

in the after-burning section of the furnace

7

3. COUPLING INTERFACES


lignite

~

HP

FWH

HP LP

BFWP

FWT

CP C

SHT

ECO

EVAP

RHT

CT

CWP

IP

50 Hz

ESP

FGD

1

2

1

2

clean gas

air

CAPH

DM

LP

FWH

ANNEX

IDF

residue

& gases


Future power plant

Target: investigation

of different coupling

scenarios

► MP steam: injection into

feed line of BFWT/FWH

and FBD

► LP steam: feedwater

heating and injection into

feed line of FBD

► Carbon residue & gases:

after-burning section

(one/both blocks)

8



lignite

~HP LP

BFWP

FWT

CP C

SHT

ECO

EVAP

RHT

CT

CWP

IP

50 HzFGD

1

2

clean gas air

DM

LP

FWH

HP

FWH

C

FBD

2

1

HP-ABEco

LP-ABEco

FGTS

BFWT

ANNEX

3

3

IDF

ESP CAPH

I

II

I

II

CAPH

2 x

residue

& gases


Residual & sour gases: positive pressure; ~30 °C; major components (at STP)

Sour gas: 96.3 … 97.1 vol.-% CO2

1.2 … 1.7 vol.-% H2S

0.2 … 0.3 vol.-% CO+H2

386 … 960 ppmv COS

181 … 222 ppmv NH3

MeOH synthesis: purge gas (~79 vol.-% H2)

light ends (~23 vol.-% CH3OH)

MtG synthesis: off gas (~92 vol.-% C1-C4)

Carbon residue (FBG only): 1 atm; ~100 °C

34 wt.-% carbon; 66 wt.-% ash

14.8 MW thermal input (11.5 MJ/kg LHV)

9



1,0

1,0

1,1

1,1

9,7

9,4

16,9

17,2

13,7

12,7

20,6

20,2

0 5 10 15 20 25

SFG+H2

SFG

HTW+H2

HTW

SFG+H2

SFG

HTW+H2

HTW

SFG+H2

SFG

HTW+H2

HTW

FTM

TOM

TG

the

rmal

rat

ing

(MW

)

residual & sour gases

► Flue gas: 0.3 … 2.9 vol.-% [existing plant] and 0.2 … 2.6 vol.-% [future plant]

► SO2: 120-253 mg/m³ (STP) [existing plant] and 89-255 mg/m³ (STP) [future plant]

► CO2: 26-89 g/kWh(el) [existing plant] and 15-71 g/kWh(el) [future plant]

FBG

FBG+H2

FBG

FBG

EFG

EFG+H2

FBG+H2

EFG

EFG+H2

FBG+H2

EFG

EFG+H2

20.2

20.6

12.7

13.7

17.2

16.9

9.4

9.7

1.1

1.1

1.0

1.0


MP steam: 40 bar; 253‒262 °C LP steam: 5 bar; 170‒187 °C

10



8,9

8,9

19,6

25,1

26,9

25,0

41,3

44,1

38,6

34,7

52,6

52,8

0 20 40 60 80

SFG+H2

SFG

HTW+H2

HTW

SFG+H2

SFG

HTW+H2

HTW

SFG+H2

SFG

HTW+H2

HTW

FTM

TOM

TG

the

rmal

rat

ing

(MW

)

MP steam 77,5

70,7

69,4

56,2

41,2

39,9

25,5

29,2

36,8

36,3

21,4

26,0

0 20 40 60 80

SFG+H2

SFG

HTW+H2

HTW

SFG+H2

SFG

HTW+H2

HTW

SFG+H2

SFG

HTW+H2

HTW

FTM

TOM

TG

the

rmal

rat

ing

(MW

)

LP steamFBG

FBG+H2

FBG

FBG

EFG

EFG+H2

FBG+H2

EFG

EFG+H2

FBG+H2

EFG

EFG+H2

FBG

FBG+H2

FBG

FBG

EFG

EFG+H2

FBG+H2

EFG

EFG+H2

FBG+H2

EFG

EFG+H2

52.8

52.6

34.7

38.6

44.1

41.3

25.0

26.9

25.1

19.6

8.9

8.9

26.0

21.4

36.3

36.8

29.2

25.5

39.9

41.2

56.2

69.4

70.7

77.5


Total heat input: steam; gases; carbon residue

Power plant efficiency stand-alone (LHV)

el: electric | aux: auxiliaries

Power plant efficiency with Annex integration

C: coal | S: steam | W: feedwater | G: gases | R: carbon residue

11



87,4

80,6

104,8

97,1

77,8

74,3

98,3

105,2

89,1

83,7

109,3

114,2

0 20 40 60 80 100 120

SFG+H2

SFG

HTW+H2

HTW

SFG+H2

SFG

HTW+H2

HTW

SFG+H2

SFG

HTW+H2

HTW

FTM

TOM

TG

the

rmal

rat

ing

(MW

)

𝜂𝑃𝑜𝑤𝑒𝑟 =𝑃𝑒𝑙 [−𝑃𝑎𝑢𝑥]

ሶ𝑄𝐶

𝜂𝑃𝑜𝑤𝑒𝑟+𝐴𝑛𝑛𝑒𝑥 =𝑃𝑒𝑙 [−𝑃𝑎𝑢𝑥][+0.2⋯0.25 ⋅ ሶ𝑄𝑆,𝑒𝑥𝑝𝑜𝑟𝑡]

ሶ𝑄𝐶 + ሶ𝑄𝑆,𝑖𝑚𝑝𝑜𝑟𝑡 − ሶ𝑄𝑊 + ሶ𝑄𝐺 + ሶ𝑄𝑅

FBG

FBG+H2

FBG

FBG

EFG

EFG+H2

FBG+H2

EFG

EFG+H2

FBG+H2

EFG

EFG+H2

114.2

109.3

83.7

89.1

105.2

98.3

74.3

77.8

97.1

104.8

80.6

87.4


Net plant efficiency: reference case vs. Annex integration

existing power plant: -0.4 … -0.8 (100 %) | -0.4 … -1.0 (50 %) future power plant: -0.6 … -0.9 (100 %) | -1.4 … -2.2 (40 %)

12

4. MODELING RESULTS


-6,0

-5,5

-5,0

-4,5

-4,0

-3,5

-3,0

-2,5

-2,0

-1,5

-1,0

-0,5

0,0

50 55 60 65 70 75 80 85 90 95 100

net

pla

nt

effi

cie

ncy

ch

ange

(%

-po

ints

)

boiler capacity (%)

EFG-MTG FBG-MTG

EFG-MTO FBG-MTO

EFG-FT FBG-FT

reference

-6,0

-5,5

-5,0

-4,5

-4,0

-3,5

-3,0

-2,5

-2,0

-1,5

-1,0

-0,5

0,0

40 45 50 55 60 65 70 75 80 85 90 95 100

net

pla

nt

effi

cie

ncy

ch

ange

(%

-po

ints

)

boiler capacity (%)

EFG-MTG FBG-MTG

EFG-MTO FBG-MTO

EFG-FT FBG-FT

reference(existing plant) (future plant)

0.0

-6.0

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

-4.5

-5.0

-5.5

0.0

-6.0

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

-4.5

-5.0

-5.5


Coal savings: heat input by Annex integration results in less coal demand (and CO2 emissions)

existing power plant: FBG-MTG -21 … -51 g CO2 / kWh(el) future power plant: FBG-MTG -1 … -6 g CO2 / kWh(el)

13

4. MODELING RESULTS


1

2

3

4

5

6

7

8

9

50 55 60 65 70 75 80 85 90 95 100

coal

sav

ings

co

mp

are

d t

o r

efe

ren

ce (

%)

boiler capacity (%)

EFG-MTG EFG-MTO EFG-FT

FBG-MTG FBG-MTO FBG-FT

1

2

3

4

5

6

7

8

9

40 45 50 55 60 65 70 75 80 85 90 95 100

coal

sav

ings

co

mp

are

d t

o r

efe

ren

ce (

%)

boiler capacity (%)

EFG-MTG EFG-MTO EFG-FT

FBG-MTG FBG-MTO FBG-FT

existing power plant future power plant


Steam injection: impacts and possible limitations over plant load – example: FBG-MTG

MP steam injection into cold reheat pipeline MP steam injection into feed line of BFWT/FWH

14

4. MODELING RESULTS


lignite

~

HP

FWH

HP LP

BFWP

FWT

CP C

SHT

ECO

EVAP

RHT

CT

CWP

IP

50 Hz

ESP

FGD

1

2

1

2

clean gas

air

CAPH

DM

LP

FWH

ANNEX

IDF

existing power plant

lignite

~HP LP

BFWP

FWT

CP C

SHT

ECO

EVAP

RHT

CT

CWP

IP

50 HzFGD

1

2

clean gas air

DM

LP

FWH

HP

FWH

C

FBD

2

1

HP-ABEco

LP-ABEco

FGTS

BFWT

ANNEX

3

3

IDF

ESP CAPH

I

II

I

II

CAPH

2 x

future

power

plant

Cold reheat pipeline heat stream (MW) mass flow (kg/s)

Reference case 790 … 1,402 261 … 471

Annex integration 802 … 1,416 264 … 475

- Injection absolute 53 19

- Injection relative 6.6 … 3.7 % 7.2 … 4.0 %

BFWT/FWH feed line heat stream (MW) mass flow (kg/s)

Reference case DUO 53 … 172 16 … 51

MONO 30 … 89 9 … 26

Annex integration compared to reference conditions

- Injection absolute 53 19

- Injection relative DUO 100 … 31 % 119 … 37 %

MONO 177 … 60 % 211 … 73 %


Strengths: Annex integration results in coal

savings (and less CO2 emissions)

Weaknesses: Slight efficiency loss compared

to reference plant cases

Opportunities: Improvement of load elasticity via

Annex integration

Threats: Possible limitation of steam injections

towards minimal boiler capacity

15

5. SUMMARY


54

51

44

39

37

34

22

20

16

10

0

97

91

10

0

98

94

49

48

44

0

20

40

60

80

100

existing power plant SINGLE future power plant DUO future power plant MONO

rela

tive

net

ele

ctri

city

ge

ne

rati

on

(%

)

existing powerplant SINGLE

future powerplant DUO

future powerplant MONO

reference Annex integration Annex integration including electrolysis

Note: Annex integration averaged amongst all scenarios


Project „Concept studies of coal-based Polygeneration-Annex-plants” (03ET7042A)

Supported by: Participating companies:

RWE Power AGForschung und Entwicklung

16

ACKNOWLEDGEMENT



For enquiries or further questions, please contact:

Clemens Forman

Email: [email protected]

Phone: +49 (0) 3731 39 4806

Fax: +49 (0) 3731 39 4555

Website: www.iec.tu-freiberg.de

17

THANK YOU FOR YOUR ATTENTION!



References

C. Wolfersdorf, K. Boblenz, R. Pardemann, B. Meyer; Syngas-

based annex concepts for chemical energy storage and improving

flexibility of pulverized coal combustion power plants; Applied

Energy 156 (2015) 618-627; doi:10.1016/j.apenergy.2015.07.039

M. Gootz, C. Forman, B. Meyer; Coal-to-Liquids: An attractive

opportunity for improved power plant capacity utilization?; 8th

International Freiberg Conference on IGCC & XtL Technologies –

Innovative Coal Value Chains, Cologne, Germany, 12.-16.06.2016

C. Forman, R. Pardemann, B. Meyer; Differentiated evaluation of

the part load performance of an industrial CHP; COAL-GEN

Conference 2015, Las Vegas, Nevada/USA, 08.-10.12.2015

18

APPENDIX


Nomenclature (power plant)

ABEco air bypass economizer

BFWP boiler feed water pump

BFWT boiler feed water turbine

C condenser

CAPH combustion air preheater

CP condensate pump

CT cooling tower

CWP cooling water pump

DM drying mills

ECO economizer

ESP electrostatic precipitator

Nomenclature (Annex plant)

EFG

FBG

FT

MTG

MTO

Entrained-flow gasifier

Fluidized-bed gasifier

Fischer-Tropsch synthesis Methanol-to-Gasoline synthesis

Methanol-to-Olefins synthesis

EVAP evaporator

FBD fluidized-bed drying

FGD flue gas desulfurization

FGTS flue gas transfer system

FWH feed water heating

FWT feed water tank

HP high pressure

IDF induced draft fan

IP intermediate pressure

LP low pressure

MP medium pressure

RHT reheater

SHT superheater

coupling of power generation with syngas-based chemical

Documents