operating experience with fluidized bed coal dryer at coal creek generating station - john weeda,...

G ti S itGeneration Summit

February 7-8, 2012 San Antonio, TXSan Antonio, TX

John WeedaDirector, North Dakota Generation

Great River Energy

Great River Energygy

Generation & transmission cooperati e• Generation & transmission cooperative

• 28 member cooperatives in MN and WI

• Serving 645 000 homes & businesses• Serving 645,000 homes & businesses

• 850 employees

• $850 million revenue$850 million revenue

• $3.3 billion total assets

• Investment grade debt

• 2,800+ MW of generation

• 4,500+ miles of transmission lines

Background –Th "T i l B tt Li "The "Triple Bottom Line"

• Great River Energy has a• Great River Energy has a commitment to provide customers with:

Stable rates

ReliabilityReliabilityReliabilityReliabilityRatesRatesRatesRates

– Stable rates– Reliable electricity– Environmental stewardship EnvironmentEnvironmentEnvironmentEnvironment

• Members annually approve:– Rates– New projects– Environmental investments

A P i E l f thA A Premier Example of the Innovative Spirit

Coal Creek Station Units 1&2Coal Creek Station Units 1&2• 2 X 600 MW Tangentially Fired,

Dual Furnace

• 8 X 8 burners, plus SOFA

• Eight Pulverizers per Unit• Eight Pulverizers per Unit

• Mine Mouth, ND Lignite

o Contract thru 2045

o 6,200 BTU/lb (14.4 MJ/kg)

o 38% moisture

o Approximately 8M tons/yrpp y y

• Commissioned 1979, 1981

• Wet FGD’s from original design

Cl d L C li• Closed Loop Cooling

• DC transmission to Minnesota

Why should DryFine technology be f i t t t ?of interest to you?

Dual ReheatUltra-SuperCritical at 1120F/1120F (604C/604C)

Low-T Fuel DryingUltra-SuperCritical at 1256F/1292F (680C/700C)

Advanced Ultra-Supercritical at 1350F/1400F (732C/760C)

Low-T Feedwater Pre-heatingLow-T Air Pre-Pre-heating

Reduce cooling tower approach temperatureNatural Draft Cooling Tower

Dual Reheat

0% 5% 10% 15%

Reduce Air Heater Leakage (6% to 1%)

Heat Rate Improvement, % Baseline

Figure 2-24Comparison of Heat Rate Improvement Technologies Baseline is 1080°F/1080°F/3800 psi steam cycle (582°C/582°C/262 bar), 87.2% efficient boiler firing PRB coal with mechanical draft cooling towers. Baseline Unit Heat Rate is 8,982 Btu/kWh (9,497 kJ/kWh).From:CoalFleet Guideline for Advanced Pulverized Coal Power Plants: Version 5 EPRI Palo Alto CA: 2009 1015698CoalFleet Guideline for Advanced Pulverized Coal Power Plants: Version 5. EPRI, Palo Alto, CA: 2009. 1015698.

Problem Statement:The Friday Afternoon Brainstorm Question

• Plant performance is based on 6,800 BTU/lb (15.8 MJ/kg) fuel (with ( g) (normal margins), but delivered fuel HHV has rarely exceeded 6,200 BTU/lb (14.4 MJ/kg)

• As a result• As a result….

• Lost Boiler And Cycle Efficiency

– 9% Higher Coal Flow Rate Than Design

– 20 MW Of Station Service Power

– 20% Higher Flue Gas Flow Rate Than Design

High Exit Gas Temperature– High Exit Gas Temperature

• Lost Spare Mill Capability

• Increased Operating And Maintenance Costs

• Flue Gas Flow Limited Scrubbers!

Culture of InnovationCulture of Innovation

• Is a “Friday afternoon” brainstorm session allowed, encouraged or frowned upon?

• Do employees have the big picture of what improvements in their area of responsibility can do for the company?

• Is plant performance a “tracking” program or an “improvement” program?p g

Solution • Objective….

• Restore lost performance by removing moisture in the incoming fuel• Restore lost performance by removing moisture in the incoming fuel stream just prior to bunkering

• How….• Employ waste heat to reduce moisture content of the lignite conveyed to

the bunkersthe bunkers • Approach….

• Demonstrate and Select Basic Drying Process Concept• Develop “Proof Of Concept” Pilot Plant• Develop Dryer Design And Predictive Performance Modeling• Prototype Full Scale Dryer Design • Integrate Full Scale Commercial Demonstration Into Existing Plant

ProjectProject

Coal Pile Testing, Initial Fluidized Bed

Pilot Dryer2 Ton/hr

Phase 2Commercial Application

Phase 1Prototype

DryerFluidized Bed Dryer Design

2002

2 Ton/hr2003- Present

Application2009

Dryer 112Ton/hr2005-2009

Culture of InnovationCulture of Innovation

• Are employees free to try new things?

• Is failure acceptable?• Is failure acceptable?

• Is there some funding available for improvement development?

• Would you support a pilot study?

• Is a prototype a taboo thought?

DryFiningTM Process

NOx

Culture of InnovationCulture of Innovation

• Are integrated solutions encouraged?

• Is boiler efficiency equivalent to environmental controls?

Is reduced maintenance cost a valid factor in economic evaluation?• Is reduced maintenance cost a valid factor in economic evaluation?

• Can you take credit for reduced company staff time without a layoff?

Collaborative Development Effort

Prototype Coal Dryeryp y

M i it 112 5 t /h• Maximum capacity - 112.5 tons/hr

• Removed approx. ¼ of coal moisture.

– Dried lignite from 38.5% to 29.5% moisture

– Improved HHV from 6,200 BTU/lb (14.4 MJ/kg) to 7,045 BTU/lb (16 4 MJ/kg)(16.4 MJ/kg)

• Fully automated operation, integrated into the plant control system.

Six patent applications on dryer design and control filed by GRE• Six patent applications on dryer design and control filed by GRE (two awarded).

Culture of InnovationCulture of Innovation

• Will your operators support operation of a prototype?

• How will maintenance support the need to keep a prototype running?

• Is collaboration embraced as a way to leverage knowledge and innovation?

Boiler Efficiency Improvement from the Prototypefrom the Prototype

3.0

Theory

2 0

2.5

nt [%

Abs

]

Theory

Test Result

1.5

2.0

cy Im

prov

eme

ctio

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0 5

1.0

oile

r Effi

cien

c

Moi

stur

e R

educ

0.0

0.5

0 1 2 3 4 5 6 7 8 9 10

Bo

Targ

et

Reduction inTotal Moisture in Coal [% Abs]

Segregation Stream from the PrototypePrototype

Sulfur and Hg in Segregation Stream

60.00%

50.00%

Mercury

30.00%

40.00%

%

%S in UC

%Hg in UC

20.00%

%Hg in UC

Sulfur

0.00%

10.00%

5/31/06 6/3/06 6/5/06 6/6/06 6/7/06 6/8/06 6/9/06 6/12/06 6/13/06 6/14/06

date

The Transition from Prototype to Commercial

• Pursue the one unit at a time original concept?

• Evaluating least cost options

DryFining – the clear choice

02007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018

nefit

sst

s N

et B

enm

ulat

ive

Cos

Present Value difference between the cases exceeds

$292 million in value

Cum

m

Confidential 19Alternative Case - No Coal Drying Base Case - Coal Drying

Culture of InnovationCulture of Innovation

• Is a least cost model vs. an ROI model acceptable?

• Does the board trust management enough to authorize a project like this?

• Will management and the board support the rough spots in the road as serial number one issues of budget, schedule, and startup issues need resolutionneed resolution.

Culture of InnovationCulture of Innovation

• Are you willing to make proactive environmental improvements?

• Do your employees have enough ownership of their equipment to make it thru serial number one issues?

Not just the engineers- how about your Mechanics, Electrical j g y ,and Instrument Technicians, Operators, Fuel Handlers and others?Do they work collaboratively or throw problems back and forth?y y p

Looking at the result in January 20102010

SO2 Reduction2

0.800

0.900

0.600

0.700

N btu

0.500

lB/m

ILLION

0.300

0.400GREAT RIVER ENERGYCoal  Creek Station

DryFining  Full Load SOx ImpactJCKennedy ‐5/14/2010

8-Sep-11230.200

10/14/09 11/3/09 11/23/09 12/13/09 1/2/10 1/22/10 2/11/10 3/3/10 3/23/10 4/12/10

NOx ReductionNOx Reduction0.300

0.250

GREAT RIVER ENERGYCoal Creek Station - Unit #2

Hourly Full Load NOx Readings - Oct 2009 to April 20105/25/2010 - JCKennedy

106BTU)

0.200

NOx (lb/1

0.150

0.100

10/14/09 11/3/09 11/23/09 12/13/09 1/2/10 1/22/10 2/11/10 3/3/10 3/23/10 4/12/10

Summary: HgT

Coal Creek Unit 1: sCEM: Total Mercury

y g

Coal Creek Unit 1: sCEM: Total Mercury

16

18

20

g/dN

m3 ] Wet Coal Baseline

Dried Coal

12

14

16

n in

Flu

e G

as [ μ

g

6

8

10

y C

once

ntra

tion

2

4

6

Tota

l Mer

cury

0APH Inlet FGD Inlet FGD Bypass FGD Outlet Stack

Measurement Location

DryFining Results

25% less H2O - dry lignite from 38 to 29% moisture, improving HHV from 6,100 to 6,800 BTU/lb

54% less SO2 - Segregation of ash minerals, plus improved collection efficiency

40% less Hg - Segregation of ash minerals, plus improved collection efficiency

32% less NO Reduced volumetric release rate improved32% less NOX - Reduced volumetric release rate, improved fineness and air & fuel distribution to furnace

4% less CO2 - 4% improved cycle efficiency4% less CO2 - 4% improved cycle efficiency

Meeting the Challenge of Marketing the Technology

• DOE requirement that the technology be made commercially available to others

• Repayment to DOE based in part on sale of technology

• Developing commercialization partners

• GRE not DryFine IncGRE not DryFine, Inc.

Process integrations (completed)g ( p )

Gasifiers• Gasifiers– Integrated Gasification Combined Cycle– Coal to Liquids

• Super Critical Pulverized Coal

• Activated Carbon

• Oxy-fuel firing

• Confidentiality agreements in place

• 50% Global reserves would benefit

Other GRE Successes from a B i I t C ltBusiness Improvement Culture

Efficiency ImprovementsEfficiency Improvements

Turbine bladesCooling TowersSimulator

DryFiningbeneficiation

4% 800 000 tons totalSimulatorVentilationVariable packingFans/VFD’s

4%, 800,000 tons total

Over $316,000,000 invested inOver $316,000,000 invested inFans/VFD sControlsLeak detectionCompressed air

Over $316,000,000 invested in Over $316,000,000 invested in environmental and efficiency environmental and efficiency improvements since 1979improvements since 1979

Compressed air605,771 tons total

Precision Maintenance Successes

C li T F f 2 f il / t $36 000 h t 12• Cooling Tower Fans-from 2 failures/yr at $36,000 each to 12 years with no failures

• Heater Drains Pump- annual rebuild to 8+ year life saving $5000/year

• Condensate pumps- 7 year life to 15+ years saving $49,000/pump X 6 pumps

• Valve maintenance- saving $14,000 to $100,000/year

• Boiler Feed pumps increase life between overhauls avoided• Boiler Feed pumps- increase life between overhauls avoided purchase of new pump for $550,000

Concluding Point of ViewConcluding Point of View

Whatever you call your drive for excellence a host of opportunities awaitexcellence, a host of opportunities await

you which, like DryFine, will improve your bottom line when you fosteryour bottom line when you foster

innovation.

Any questions???Any questions???