increasing the flexibility of igccflexibility of igcc...
Post on 25-Mar-2018
230 Views
Preview:
TRANSCRIPT
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.
3© 2015 Electric Power Research Institute, Inc. All rights reserved.
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
4© 2015 Electric Power Research Institute, Inc. All rights reserved.
* 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
5© 2015 Electric Power Research Institute, Inc. All rights reserved.
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.
6© 2015 Electric Power Research Institute, Inc. All rights reserved.
Polygeneration – HECA Example
7© 2015 Electric Power Research Institute, Inc. All rights reserved.
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%
8© 2015 Electric Power Research Institute, Inc. All rights reserved.
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).
9© 2015 Electric Power Research Institute, Inc. All rights reserved.
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.
10© 2015 Electric Power Research Institute, Inc. All rights reserved.
GE FlexEfficiency 60 Hot Start Timing
11© 2015 Electric Power Research Institute, Inc. All rights reserved.
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
12© 2015 Electric Power Research Institute, Inc. All rights reserved.
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
13© 2015 Electric Power Research Institute, Inc. All rights reserved.
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%
14© 2015 Electric Power Research Institute, Inc. All rights reserved.
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?
15© 2015 Electric Power Research Institute, Inc. All rights reserved.
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
16© 2015 Electric Power Research Institute, Inc. All rights reserved.
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)
17© 2015 Electric Power Research Institute, Inc. All rights reserved.
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).
18© 2015 Electric Power Research Institute, Inc. All rights reserved.
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
19© 2015 Electric Power Research Institute, Inc. All rights reserved.
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.
20© 2015 Electric Power Research Institute, Inc. All rights reserved.
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
21© 2015 Electric Power Research Institute, Inc. All rights reserved.
Minutes
3%/min. Syngas Ramping with NG Boost
22© 2015 Electric Power Research Institute, Inc. All rights reserved.
5%/min. Syngas Ramping with NG Boost
23© 2015 Electric Power Research Institute, Inc. All rights reserved.
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.
24© 2015 Electric Power Research Institute, Inc. All rights reserved.
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
chris@higman.de
25© 2015 Electric Power Research Institute, Inc. All rights reserved.
Together Shaping the Future of ElectricityTogether…Shaping the Future of Electricity
26© 2015 Electric Power Research Institute, Inc. All rights reserved.
top related