Increasing the Flexibility of IGCCFlexibility of IGCC ...tu-freiberg.de/sites/default/files/media/professur-fuer-energiever...Increasing the Flexibility of IGCCFlexibility of IGCC

Increasing the Flexibility of IGCCFlexibility of IGCC

Power Plants

Chris HigmanChris HigmanHigman Consulting GmbH

Jose Marasigan, EPRI Doug Todd, Process Power Plants LLC

G S CDan Kubek, Gas Processing Solutions LLCJim Sorensen, Sorensenergy LLC

7th International Freiberg Conferenceon IGCC & XtL Technologies

© 2015 Electric Power Research Institute, Inc. All rights reserved.

on IGCC & XtL Technologies 9th June, 2015, Hohhot, China

Overview

Background– Need to accommodate more renewables but keep coal in the mixNeed to accommodate more renewables, but keep coal in the mix

Ramping Issues and Opportunities for IGCC’sAmongst coal options IGCC uniquely amenable toAmongst coal options, IGCC uniquely amenable to

– Polygeneration– Natural gas boostg– Rapid response IGCC

Performance of Rapid Response IGCC

2© 2015 Electric Power Research Institute, Inc. All rights reserved.

Background

Increased penetration of intermittent renewables (wind, solar) into electricity supply requires increased flexibility from so a ) to e ect c ty supp y equ es c eased e b ty ofossil (and biomass) -based power producers.NG Combined Cycle vendors have reacted with quicker y q

ramping products. IGCCs are in a position to benefit from rapid response CCs.


Ramping Issues for IGCCs

Existing gasification systems (including IGCC) are generally designed for base loaddes g ed o base oad– Economic reasons– Technical limits for ramping have not been pushed

Published data*:– Ramp rate (3%/min.)– Minimum turndown 60-70%, but with multi-burner configurations

<40% is possibleStart up time– Start up timeCold start: 2 hrs (membrane wall), 80-90 hrs (refractory lining)Hot start: 0.5 hrs (membrane wall), 6-8 hrs (refractory lining)( ), ( y g)

But some of these numbers are technology-specific


* IEA CCC Report 242

IGCC Plant Ramping Example – Nakoso 250 MW IGCC

Source : Joban Joint Power Co., Tetsuji Asano, "Progress in Japanese Air-blown IGCC Demonstration Project Update", presented at Coal Gasification Symposium on April 26, 2012.

Demonstrated unloading Sustained stable part- Controlled ramp to


and loading ramp rates load operation 100% load

Routes to Improved IGCC Ramp Rate

Polygeneration– Keep syngas production stableKeep syngas production stable– Swing syngas use between power generation and chemical

production– Design to optimize asset utilization

Rapid Response IGCC (50% - 100%)– Use rapid response combined cycle plants– Use natural gas boost while syngas catches up, or

Cut back on limitations to syngas ramping– Cut back on limitations to syngas ramping

Two-shift operation not considered– certainly not attractive with refractory lining butwith refractory lining, but– Good, low output parking points can be designated for off-peak

operation.


Polygeneration – HECA Example


Adapted from: Loney & Sakamoto, GTC 2013

HECA Polygen Load Cycling Plan

Gasification Syngas Load Ammonia Urea & UAN ASU, Cleanup, CO2

distribution Storage Fertilizer

Daytime 100% 71.3% Power blocky(16 hrs/day) 100%

28.7% PSA / NH360%

Draw down 100%60%

Nighttime(8 hrs/day)

100% 52.1% Power block65%

47 9% PSA / NH B ild 100%47.9% PSA / NH3100%

Build up 100%


Adapted from: Loney & Sakamoto, GTC 2013

Ramping Performance in Polygen Scenario

Experience of sudden unloading of ammonia synthesis exists on gasifier trip in multi-gasifier plants.g p g pPower increase ramp rate is determined by CC

(~12 %/min.).Power decrease ramp rate (without flaring) is limited by

ammonia synthesis (or N2 wash column where applied).


Rapid Response CCs

GE Flex 50, Flex 60 seriesSiemens FlexPlant series operating at Secunda CA andSiemens FlexPlant series operating at Secunda, CA and

Panda, TXDifferent degrees of ‘rapid response’ are offered.Different degrees of rapid response are offered.

– Fastest responses will increase maintenance cost.


GE FlexEfficiency 60 Hot Start Timing


Source: GE‘Hot start’ after less than 8 hours shutdown

RR NGCC Ramp up from 50% to 100%

800

900

1000

600

700

800

W

Steam TurbineW

300

400

500MW

Steam Turbine

MW

100

200

300

Gas Turbine

00 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15N lG

Minutes

N lG


Main IGCC Components

Flue gas~ ~

SaturatorGasTurbineHRSGSteam

Turbine

Coal N2 CO2

Gasifier Syngas Cooling

Acid GasRemoval

O

CO ShiftCoal Prep.(wet or dry)

Sulphur Recovery

O2

WWTO

N2

ASU eco e y

Sulphur orH SO

Waste Water/ Salt

SlagO2


H2SO4

Study for IGCC Ramp from 50% to 100%

MWe at MWe at 100% load 50% load

Combustion turbine 573 299Steam turbine 382 216Steam turbine 382 216Gross output 955 515Aux. power CCU -18 -10ASU -169 -118Other aux. power -18 -12T t l 205 140Total aux. power 205 -140Net output 750 375

Aux. power % of gross output 21.5% 27.2%


IGCC Ramping Issues – Syngas supply

Ambient start limitations will depend of type of gasifier (refractory vs. water wall)( e acto y s ate a )

Fast ramp from 50% to 100% possible in two scenariosFast ramp from 50% to 100% possible in two scenarios– Standard syngas ramp rate (3%/min.) with natural gas boost to bridge

time until syngas production has caught up.– Where are bottlenecks to increasing ramp rate to 5%/min. or more?


Oxygen Plant (ASU)

Vendors could probably work something out, but in any case only minutes worth of oxygen storage capacity required to bridge catch up.O ti DGAN l ti d i ( t LIN tOptimum DGAN solution under review (steam or LIN top-up).

ASU GASIFIER

LOXVAPORIZER


Gasifier

• Temperature and pressure remain unchanged.• Key is control of oxygen/carbon (O/C) ratio• O/C is not the same as O2/coal• EPRI is supporting two programs to enable real time process control response

to changes in fuel compositionto changes in fuel composition.

• Laser-induced breakdown spectroscopy (LIBS) for fuel monitoring (Lehigh University)

• Laser absorption monitoring of gas t t ( d iti ) itemperature (and composition) in a high pressure coal gasifier. (Stanford and Utah)


Source: Marasigan, GTC 2012

Acid Gas Removal – The Current Bottleneck

• Sulfur-breakthrough if ramped up too fast (>~3%).up too fast ( 3%).

• Experience with very fast ramp down on multi-gasifier i t ll tiinstallations.

• On ramp up, time is required to build up additional solvent hold pup on trays or packing. While this is happening, lower trays are starvedare starved.

• EPRI is working to address this issue (Dynamic simulation t TU D t dt)at TU-Darmstadt).


CO Shift Load Swings

Fast unloading known from multi-gasifer configurations. But fast loading?

Frequent load changes? Frequent load changes?– Load change will cause

temperature swing of individual catalyst particles.

– Effect of a large number of cycles on catalyst life is uncertain.

Change of temperature profile with load


Combined Cycle

Gas Turbine/HRSG– Current offerings with up to 12%/min.

Steam Turbine– Much slower than GT on hot start up (temperature distribution).– Ramping from 50% to 100% capability still under investigation, but

probably betterprobably better.


Anticipated Ramp Times (50-100%) for Generic IGCCUsing rapid response NGCC componentsg p p p

1000

800

900

1000

600

700

Net

Out

put

400

500

MW

eN

ScenarioRamp Time

375 to 750 MW(min)

100

200

300Syngas 3%/minSyngas 5%/minSyngas 3%/min + NG BoostSyngas 5%/min + NG Boost

IGCC 3%/min syngas only 12.1IGCC 5%/min syngas only 6.5IGCC 3%/min syngas + NG boost 5.8IGCC 5%/min syngas + NG boost 4.8

0

100

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Syngas 5%/min + NG BoostNG ramp from 50%

Minutes

IGCC 5%/min syngas NG boost 4.8NGCC 5.2


Minutes

3%/min. Syngas Ramping with NG Boost


5%/min. Syngas Ramping with NG Boost


Preliminary Conclusions

IGCC can support flexible operations much better that generally assumed.NG boost requirement for 50-100% load ramp is surprisingly

small.– With currently proven syngas ramping performance boost is required forWith currently proven syngas ramping performance boost is required for

only 12 minutes.– With minor improvements to syngas ramping performance this can be

reduced to 6 minutes peaking at 20% of GT loadreduced to 6 minutes peaking at 20% of GT load.

With NG boost IGCC technology can deliver near-NGCC ramping capability over 50-100% load range. In areas without natural gas, this can be applied to other, storable

fuelsfuels.Some additional R&D needed to validate results.EPRI is already supporting some of these R&D programs.


y pp g p g

Author’s Acknowledgement

The content of this paper was developed as part of a project of the Electric Power Research Institute

(EPRI).(EPRI). Further details are contained in EPRI Report # 3002003742.

iwww.epri.com

[email protected]


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Increasing the Flexibility of IGCCFlexibility of IGCC ...tu-freiberg.de/sites/default/files/media/professur-fuer-energiever...Increasing the Flexibility of IGCCFlexibility of IGCC