Role of Coal in Modern Electricity Role of Coal in Modern - - PowerPoint PPT Presentation

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Role of Coal in Modern Electricity Role of Coal in Modern - - PowerPoint PPT Presentation

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Role of Coal in Modern Electricity Role of Coal in Modern Electricity Generation Systems Generation Systems Energy and Environment Seminar Series Energy and Environment Seminar Series John Kramlich John Kramlich UW Mechanical Engineering UW

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SLIDE 1

Role of Coal in Modern Electricity Role of Coal in Modern Electricity Generation Systems Generation Systems

Energy and Environment Seminar Series Energy and Environment Seminar Series

John Kramlich John Kramlich UW Mechanical Engineering UW Mechanical Engineering December 2, 2010 December 2, 2010

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SLIDE 2

US Energy Usage (Quads=E+15 BTU)

Coal

Total

Renewable Nuclear Natural Gas Petroleum

Total

Electricity Heating Transportation

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SLIDE 3

US Energy Usage

Coal

Total

Renewable Nuclear Natural Gas

37.1 0.4 10.3 26.3

Petroleum

Total

Electricity Heating Transportation

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SLIDE 4

US Energy Usage

Coal

Total

Renewable Nuclear

23.8 6.9 16.2 0.7

Natural Gas

37.1 0.4 10.3 26.3

Petroleum

Total

Electricity Heating Transportation

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SLIDE 5

US Energy Usage

Coal

Total

Renewable

8.5 8.5

Nuclear

23.8 6.9 16.2 0.7

Natural Gas

37.1 0.4 10.3 26.3

Petroleum

Total

Electricity Heating Transportation

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SLIDE 6

US Energy Usage

Coal

Total 7.7 4.1 2.7 0.8

Renewable

8.5 8.5

Nuclear

23.8 6.9 16.2 0.7

Natural Gas

37.1 0.4 10.3 26.3

Petroleum

Total

Electricity Heating Transportation

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SLIDE 7

US Energy Usage

22.5 20.5 1.8

Coal

99.6 40.5 21.4 27.8 Total 7.7 4.1 2.7 0.8

Renewable

8.5 8.5

Nuclear

23.8 6.9 16.2 0.7

Natural Gas

37.1 0.4 10.3 26.3

Petroleum

Total

Electricity Heating Transportation

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SLIDE 8

Historical Trends

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SLIDE 9

US Energy Usage

20.5

Coal

40.5 Total 4.1

Renewable

8.5

Nuclear

6.9

Natural Gas

0.4

Petroleum

Total

Electricity Heating Transportation

~1 cubic km/yr

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SLIDE 10

Conventional Power Plant

Air Coal: 100% CO2 H2O SO2 NO Particles ~36% ~64%

Generator

Scrubber for SO2 Catalyst for NO Electrostatic Filter for Particles

Steam Pump Cooling Water

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SLIDE 11
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SLIDE 12
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SLIDE 13

The Achilles Heel

  • Huge thermodynamic

irreversibility between flame and steam

  • Option 1: Plug the hole

with a new cycle

  • Option 2: Move the steam

closer to the combustion

Research: Increase maximum metalurgical temperature

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SLIDE 14

Insert a Second Cycle

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SLIDE 15

Insert a Second Cycle

  • Second cycle is

mercury

  • More heat accepted at

higher temperatures

  • Several of these plants

built and operated in the 1930’s-1940’s

Still under metallurgical limit

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SLIDE 16

Increase Steam Pressure

  • Supercritical Rankine
  • Many new boilers today

Research: Corrosion resistance at high T and 30 MPa (300 atm)

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SLIDE 17

Coal Composition

  • C
  • H
  • O
  • N (~1%)
  • S (0.5-6%)
  • Main Minerals
  • Trace Minerals
  • CO2
  • H2O
  • N2 or NO
  • SO2
  • Ash (Si, Fe, Na, K, Mg,

Ca, Al)

  • As, Se, Pb, etc., U, Hg
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SLIDE 18

Environmental Cost Huge

Catalyst for NO control Ash Control SO2 Scrubber Hg Control Scrubber cost at Centrailia: $200,000,000 for 1340 MW ($149/kW)

Research: Economical and effective Hg control

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SLIDE 19

Mercury Problem

US Anthropogenic 159 tons/yr US Coal 52 tons/yr

  • Original proposal:
  • 38 tons by 2010
  • 18 tons by 2018
  • Vacated by court
  • New rule on the way
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SLIDE 20

Environmental Fate

Emission at Surface Elemental - Hg:

  • Lifetime: 0.5-1.5 years
  • Time to distribute

worldwide Oxidized - HgCl2:

  • Lifetime: hours
  • Falls in footprint

downstream of source

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SLIDE 21

Health Effects

  • Water-soluble Hg to lakes
  • Bacteria convert oxidized Hg to

methylmercury (highly absorbable, fat soluble, goes to brain)

  • This biochains up to fish, which are the

main path for human exposure

  • Reference dose: 0.1 µg/kg body weight/day

(0.18 g/lifetime)

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SLIDE 22

State of the Art

Fuel Air

  • 1. All Hg in fuel is vaporized
  • 2. All vaporized Hg is initially

elemental

  • 3. At furnace exit, oxidized vs.

elemental varies.

  • 4. Fraction captured is

highly variable (5-95%). Correlates with oxidized, but with scatter.

  • Oxidized: >80%
  • Elemental: <30%

Scrubber

  • 5. Spray dryer elemental:
  • ~40%
  • With activated carbon

/iodine: >90%

  • 6. Force oxidation ahead of scrubber (meets interim regulation)
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SLIDE 23

Oxidation Reactor

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SLIDE 24

Competition: Gas Turbines

Air Pump Fuel Burner Turbine Generator Hot Exhaust

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SLIDE 25

Combined Cycle

Generator Generator Gas Turbine

Generators recover ~58% of fuel energy Losses are ~42% No need for SO2, NO, particle cleanup Still make CO2 CO2

Hot Exhaust

Natural Gas Air

~42%

Pump Cooling Water

  • Connects gas turbine and

steam together

  • Each solves the others

problems

  • No environmental cleanup
  • ften needed
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SLIDE 26

Not as Simple as it Seems; But still, why not gas?

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SLIDE 27

Coal is Cheaper, Gas is Unstable

2001 2005 2008 Coal=1.25 $/Million Btu Coal=2.5 Retail gasoline: $22.5/million Btu

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SLIDE 28

Integrated Gasification Combined Cycle

Coal for Combined Cycles Air

Air Seperator Gasifier

N2 Coal S, N2 O2 Water

Generator Generator Gas Turbine Hot Exhaust

CO H2 Fuel Cleaning Air

  • Mass flow of air/products ~15x fuel flow
  • Cleanup much easier on fuel stream than product

gas

  • Smaller equipment
  • Larger driving forces for mass transfer
  • Currently, fuel cooled to room temperature for

cleaning

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SLIDE 29

Integrated Gasification Combined Cycle

Coal for Combined Cycles Air

Air Seperator Gasifier

N2 Coal S, N2 O2 Water

Generator Generator Gas Turbine Hot Exhaust

CO H2 Fuel Cleaning Air

  • Fuel cooling a thermodynamic loss
  • Research: Hot gas cleanup approaches
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SLIDE 30

Remaining Losses

  • In a well-optimized IGCC system, one of the

largest remaining thermodynamic irreversibilities is the combustor

  • Approach is to replace the combustor with

an adiabatic solid oxide fuel cell

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SLIDE 31

Solid Oxide Cell System

Air CO/H2

Compressor Turbine

To Steam Cycle Air CO/H2

Compressor Turbine

To Steam Cycle

Combustor Solid Oxide Fuel Cell Electricity Research: Lower T, lower cost SOFC

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SLIDE 32

Mountaineer West Virginia 1st Pilot Sequestration Plant 1.5% of Plant Output

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SLIDE 33

Process Flow Chart

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SLIDE 34

Spray Absorber

(NH4)2CO3 + CO2 + H2O -> 2(NH4)HCO3

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SLIDE 35

Regeneration

2 (NH4)HCO3 -> (NH4)2CO3+ CO2+ H2O Steam reverses the absorption reaction Releases pure CO2 and H2O

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SLIDE 36

CO2/H2O Compressor Station

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SLIDE 37

Well Injection Point

  • Water/CO2 mix

pressurized to ~100 atm.

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SLIDE 38

Injection to 8000 ft

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SLIDE 39

Oxyfuel Alternative

  • Must pay for air separation
  • No need to process large gas

flow through scrubber

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SLIDE 40

Economics-New Capacity

  • Simple boiler, no environmental control: 2 ¢/kW-hr
  • Coal supercritical: 10.5 ¢/kW-hr, 14 ¢/kW-hr with 90% carbon capture
  • IGCC 11.5 ¢/kW-hr, with carbon capture 16 ¢/kW-hr
  • Gas combined cycle 9 ¢/kW-hr
  • Nuclear 12 ¢/kW-hr
  • Solar tower 12, solar trough 20, PV 16-20 ¢/kW-hr
  • Wind 6-11 ¢/kW-hr (including tax credits)

http://www.ethree.com/clientlist.html http://bit.ly/Lazard2009

  • Two years ago, people were looking at nuclear, supercritical Rankine coal
  • Now they are looking again at gas. If gas prices stay down, this could be a

longer term direction.