improvement of power plant flexibility by coupling of ... · improvements by coupling of power...

11th ECCRIAUniversity of Sheffield

Improvement of power plant flexibilityby coupling of power generation

with syngas-based chemical synthesiswith syngas based chemical synthesis

Clemens Forman, Matthias Gootz, Christian Wolfersdorf, Bernd MeyerInstitute of Energy Process Engineering and Chemical Engineering, TU Bergakademie Freiberg6th September 2016, Sheffield, UK

Improvements by coupling of power generation with syngas-based chemical synthesis

1 B k d d ti ti

OUTLINE

1. Background and motivation

2 Power generation cases2. Power generation cases

3. Coupling interfaces

4. Modeling results

5. Summary

211th European Conference on Coal Research and Its Applications, Sheffield, UK, 5–7 September 2016


1. BACKGROUND AND MOTIVATION

lignite-fired power plant650‒1 100 MW(el) electric renewable

energy

lignite

650‒1,100 MW(el)

coalcombustion steam cycle

flue gas path flue gas, ash, gypsum

grid energysources

electric energyy

dryingresidual

gas

Annex plant auxiliaries

waterelectrolysis50 MW(el)

gy

Fischer Tropsch synthesis wax diesel200

carbonresidue

sourgas

steam

H2

coalgasifier

waterscrubbing CO-shift CO2/H2S

scrubbing MeOHsynthesis

MtG synthesis

MtO synthesis

Fischer Tropsch synthesis wax, diesel

gasoline

olefinsentrained-flow (EFG)

MW(th)


( )fluidized-bed (FBG) small-scale chemical synthesiswaste water pretreatment CO2O2


1. BACKGROUND AND MOTIVATION

MIN MAX MIN MAXAnnex plant servesas a power sink:

RES RES RES RESas a power sink:

▪ load elasticity ofpower plant rises▪ incorporation of

‒ auxiliary power

electricgrid

electricgrid

electricgrid

electricgrid

psurplus RES ► improved

power plantflexibilitygrid grid

or

MA

X

MIN tdow

n

grid grid

INAX ‒ auxiliary power ‒ auxiliary power

M M

shut

power plant +power

plant +

M

Annex plant

Annex plant

power plant

MA

power plant


plant plant plant plantplantplant


Existing power plant Design data Future power plant

2. POWER GENERATION CASES

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/h650 MW gross electric output 1,100 MW607 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/h170 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 °C66 mbar condenser pressure 35 mbar

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


* thermal input / efficiencies based on LHV


Power plant modeling: steady-state simulation ► part load performance


sliding

pressuredrops

efficiency102

EPP: existing power plant | FPP: future power plant

pressure curves

96

98

100

effic

ienc

y(%

)

EPP

steamcycle

flue gas path

plantmodeling

90

92

94

ve n

etpl

ant e

BRACHTHÄUSER 1998 CHALMERS 2007

LINNENBERG 2009 ELSNER 2011

FPP

heatl

auxiliarypower

boilercurves

86

88

90

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

rela

tiv

ZIEMS 2012 ROEDER 2014

HANAK 2015 RUPPRECHT 2016


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

boiler capacity (%)


Key performance data: net plant efficiency; specific auxiliary power


6,0

6,5

7,0

-0,75

-0,25

0,25

er (%

)

%-p

oint

s)

0.25

-0.75

-0.25

7.0

6.0

6.57,5

8,0

-0,25

0,25

(%)

%-p

oint

s)

0.25

-0.25

8.0

7.5

4,5

5,0

5,5

-2,25

-1,75

-1,25

xilia

ry p

owe

ncy

chan

ge (%

-2.25

-1.75

-1.25

4.5

5.0

5.5

6 0

6,5

7,0

-1 75

-1,25

-0,75

xilia

ry p

ower

ncy

chan

ge (% -0.75

-1.25

-1 75

7.0

6.5

6 0

3 0

3,5

4,0

,

-3 75

-3,25

-2,75

,

spec

ific

aux

et p

lant

eff

icie

net efficiency change

specific auxiliary power-3.75

-3.25

-2.75

3.0

3.5

4.0

5,0

5,5

6,0

-2,75

-2,25

1,75

spec

ific

aux

et p

lant

eff

icie

net efficiency change

specific auxiliary power

1.75

-2.25

-2.75

6.0

5.5

5.0

2,5

3,0

-4,25

3,75

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

boiler capacity (%)


-4.25

3.75

2.5

3.0

4,5-3,2550 55 60 65 70 75 80 85 90 95 100

ne

boiler capacity (%)


-3.25 4.5

existing power plant: 50‒100 % load future power plant: 40‒100 % load in DUO block operation (―)

711th European Conference on Coal Research and Its Applications, Sheffield, UK, 5–7 September 201645‒100 % load in MONO block operation (- -)


Existing power plant

3. COUPLING INTERFACESECO

Target: coupling interfacesrequire little constructionaleffort only

~HP LP

SHT

RHTIP

50 Hz

1

CAPH

effort only

► MP steam: injection intothe cold reheat pipeline

HPFWH

SHT

EVAP

ESP

2

air

► LP steam: installation ofan additional feedwaterheater bypassing the existingLP feedwater heating section lignite

FWH

BFWP

FGD1

2

DMIDF

LP feedwater heating section

► Carbon residue & gases:combustion / thermal treatmentin the after burning section of the furnace

FWT

CT

FGD

clean gas LPFWH

ANNEX

residue& gases

in the after-burning section of the furnace


CP C

CWP


Future power plant

3. COUPLING INTERFACESECO 1clean gas air

Target: adjustment dueto load-dependentoperation conditions

~HP LP

SHT

RHTIP

50 HzFGD

I

CAPH

operation conditions

► MP steam: injection intofeed line of BFWT/FWHand cold reheat pipeline

SHT

EVAP

HPFWH

FGTS

I

II

2and cold reheat pipeline

► LP steam: feedwaterheating and injectioninto feed line of FBD

lignite

BFWP2

DM

FWH

C

FBD1

BFWT

3

IDF

2 x

residue& gasesinto feed line of FBD

► Carbon residue & gases:after-burning section(one/both blocks)

FWT

CT

LPFWH

HP-ABEco ANNEXESP CAPH

& gases

(one/both blocks)


CP C

CWP

2LP-ABEco

3

II


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

3. COUPLING INTERFACES

Sour gas: 54 … 58 vol.-% CO238 … 43 vol.-% H2S1.1 … 2.6 vol.-% COS

MeOH synthesis: purge gas 66 … 76 vol.-% H21 … 14 vol.-% CH4

light ends 36 … 49 vol.-% H2

► FG: 0.5 … 4 vol.-%

► SO2: +10 % at FGD21 … 22 vol.-% CH3OH

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

2

► CO2: up to 27 g/kWh

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

34 wt.-% carbon; 66 wt.-% ash14 8 MW thermal input (11 5 MJ/kg LHV)14.8 MW thermal input (11.5 MJ/kg LHV)



Total heat input: steam; gases; carbon residue


FBG

MTGs

MP steam LP steam Residue & gases

FBG

MTGs

Energy Exergy

FBG

EFG

MTO

M

tion

sce

nari

os

FBG

EFG

MTO

M

tion

sce

nari

os

FBG

EFG

FTM

Ann

ex in

tegr

a

FBG

EFG

FTM

Ann

ex in

tegr

a

0 10 20 30 40 50 60 70 80 90

EFG

thermal rating (MW)

A

0 10 20 30 40 50 60 70 80 90

EFG

thermal rating (MW)A



Annex integration: mass and heat balancing


Power plant efficiency stand-alone (LHV)

el: electric | aux: auxiliaries

power plant

Power plant efficiency with Annex integration

Annex plant

C: coal | S: steam | W: feedwaterG: gases | R: carbon residue | P: product(s)

Annex plant



Net plant efficiency: reference case vs. Annex integration

4. MODELING RESULTS

-1 5

-1,0

-0,5

0,0

%-p

oint

s)

0.0

-1 5

-1.0

-0.5

-1 5

-1,0

-0,5

0,0

%-p

oint

s)

0.0

-1 5

-1.0

-0.5

3 5

-3,0

-2,5

-2,0

1,5

ency

cha

nge

(%

3 5

-3.0

-2.5

-2.0

1.5

3 5

-3,0

-2,5

-2,0

1,5

ency

cha

nge

(%

3 5

-3.0

-2.5

-2.0

1.5

-5,0

-4,5

-4,0

-3,5

et p

lant

eff

icie

EFG-MTG FBG-MTG

EFG-MTO FBG-MTO

EFG-FT FBG-FT

reference (existing plant)

-4.0

-3.5

-4.5

-5.0

5 5

-5,0

-4,5

-4,0

-3,5

et p

lant

eff

icie

EFG-MTG FBG-MTG

EFG-MTO FBG-MTO

EFG-FT FBG-FT

reference (future plant)

-4.0

-3.5

-4.5

-5.0

5 5

-6,0

-5,5

50 55 60 65 70 75 80 85 90 95 100

ne

boiler capacity (%)


-6.0

-5.5

-6,0

-5,5

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

boiler capacity (%)


-6.0

-5.5



Net plant efficiency: reference case vs. Annex integration

4. MODELING RESULTS

-1 5

-1,0

-0,5

0,0

%-p

oint

s)

0.0

-1 5

-1.0

-0.5

-1 5

-1,0

-0,5

0,0

%-p

oint

s)

0.0

-1 5

-1.0

-0.5

3 5

-3,0

-2,5

-2,0

1,5

ency

cha

nge

(%

3 5

-3.0

-2.5

-2.0

1.5

3 5

-3,0

-2,5

-2,0

1,5

ency

cha

nge

(%

3 5

-3.0

-2.5

-2.0

1.5

-5,0

-4,5

-4,0

-3,5

et p

lant

eff

icie

EFG-MTG FBG-FT


-4.0

-3.5

-4.5

-5.0

5 5

-5,0

-4,5

-4,0

-3,5

et p

lant

eff

icie

EFG-MTG FBG-FT


-4.0

-3.5

-4.5

-5.0

5 5

-6,0

-5,5

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

boiler capacity (%)


-6.0

-5.5

-6,0

-5,5

50 55 60 65 70 75 80 85 90 95 100

ne

boiler capacity (%)


-6.0

-5.5

existing power plant: -0.2 … -0.5 (100 %) | -0.1 … -0.6 (50 %) future power plant: -0.5 … -0.6 (100 %) | -0.8 … -1.1 (40 %)



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

4. MODELING RESULTS

6

7

8

eren

ce (%

)

EFG-MTG EFG-MTO EFG-FT

FBG-MTG FBG-MTO FBG-FT7

8

eren

ce (%

)


FBG-MTG FBG-MTO FBG-FT

4

5

6

mpa

red

to re

fe

4

5

6

mpa

red

to re

fe

1

2

3

al s

avin

gs c

om

2

3

4

al s

avin

gs c

om

040 45 50 55 60 65 70 75 80 85 90 95 100

coa

boiler capacity (%)

future power plant

150 55 60 65 70 75 80 85 90 95 100

coa

boiler capacity (%)

existing power plant

existing power plant: -30 … -93 g CO2 / kWh(el) future power plant: -11 … -44 g CO2 / kWh(el)



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

4. MODELING RESULTS

6

7

8

eren

ce (%

)


FBG-MTG FBG-MTO FBG-FT10

12

eren

ce (%

)


FBG-MTG FBG-MTO FBG-FT

4

5

6

mpa

red

to re

fe

6

8

mpa

red

to re

fe

1

2

3

al s

avin

gs c

om

2

4

al s

avin

gs c

om

040 45 50 55 60 65 70 75 80 85 90 95 100

coa

boiler capacity (%)

future power plant: DUO operation

045 50 55 60 65 70 75 80 85 90 95 100

coa

boiler capacity (%)

future power plant: MONO operation

future power plant: -24 … -83 g CO2 / kWh(el) [MONO] future power plant: -11 … -44 g CO2 / kWh(el) [DUO]



Load elasticity: coupling enables lowering of minimum power plant load

4. MODELING RESULTS

reference

Annex integration

100

97

91

100

98

94

100

on (%

)

g

Annex integration including electrolysis

Note: Annex integration averaged amongst all scenarios

4

60

80

city

gen

erat

io

54

51

44

39 37

34

249 48

4420

40

ve n

et e

lect

ric

22 20

16

0

0

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

rela

tiv

existing powerplant SINGLE

future powerplant DUO

future powerplant MONO



Overall evaluation: SWOT analysis from power plant point of view

5. SUMMARY

Strengths: Annex integration results in coal savings (and less CO2 emissions)

Weaknesses: slight efficiency loss compared to reference plant cases

Opportunities: improvement of flexibility respectively load elasticity via Annex integration

Threats: possible limitations for coupling interfaces towards minimal boiler capacity



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

ACKNOWLEDGEMENT

Supported by: Participating companies:

RWE Power AGForschung und Entwicklung



For enquiries or further questions, please contact:

THANK YOU FOR YOUR ATTENTION!

Clemens FormanEmail: [email protected]: +49 (0) 3731 39 4806Fax: +49 (0) 3731 39 4555Website: www.iec.tu-freiberg.de



References

APPENDIX

Nomenclature (power plant)C. Wolfersdorf, K. Boblenz, R. Pardemann, B. Meyer; Syngas-based annex concepts for chemical energy storage and improvingflexibility of pulverized coal combustion power plants; AppliedEnergy 156 (2015) 618-627; doi:10.1016/j.apenergy.2015.07.039

M. Gootz, C. Forman, B. Meyer; Coal-to-Liquids: An attractivet it f i d l t it tili ti ? 8th

ABEco air bypass economizerBFWP boiler feed water pumpBFWT boiler feed water turbineC condenser

FBD fluidized-bed dryingFGD flue gas desulfurizationFGTS flue gas transfer systemFPP future power plant

opportunity for improved power plant capacity utilization?; 8thInternational Freiberg Conference on IGCC & XtL Technologies –Innovative Coal Value Chains, Cologne, Germany, 12.-16.06.2016

C. Forman, R. Pardemann, B. Meyer; Differentiated evaluation ofthe part load performance of an industrial CHP; COAL-GENConference 2015, Las Vegas, Nevada/USA, 08.-10.12.2015

CAPH combustion air preheaterCP condensate pumpCT cooling towerCWP cooling water pump

FWH feed water heatingFWT feed water tankHP high pressureIDF induced draft fan

, g , ,

Nomenclature (Annex plant)

EFG Entrained-flow gasifierFBG Fl idi d b d ifi

DM drying millsECO economizerEPP existing power plantESP electrostatic precipitatorEVAP evaporator

IP intermediate pressureLP low pressureMP medium pressureRHT reheaterSHT superheaterFBG Fluidized-bed gasifier

FT Fischer Tropsch synthesisMTG Methanol-to-Gasoline synthesisMTO Methanol-to-Olefins synthesis

EVAP evaporator SHT superheater


improvement of power plant flexibility by coupling of ... · improvements by coupling of power...

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