Steam Turbines with Biomass fuel

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Steam Turbines in CHP

Girish Rajamani | Siemens Energy Inc. 2March, 2010

Applications of Steam Turbines

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Typical Steam Turbine Plant component efficiencies

Boiler 94.5%

Piping 99.7%

Condensing unit 58%

Turbine 87%

Gearbox 98%

Generator 98.8%

Improved by co-generation!


Efficiency

Conventional electricity only plant – 49%

CHP – 75%Source: US EPA 2002

CAPEX ($/kW): $300 - $1000 (size and app dependent) only STG

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Fuel flexibility

Agricultural biomass (beef cattle manure, cotton gin trash, corn stover, wheat straw, beef meat processing waste, broiler manure, poultry processing waste, dairy cattle manure, rice hulls, hog manure, sugarcane bagasse, peanut shells)

Forest biomass (wood energy crops, pulp and paper waste, logging residues, lumber mill residues, forest thinning waste)

Urban biomass (municipal solid waste, construction debris)

Conventional fuels: coal, natural gas, etc.


Steam turbines in CHP –Recommended Application*

Baseload and premium power for institutional buildings/campuses, industrial waste fuels, wood processing, paper and pulp, other small-scale biomass

Advantages:Large selection of fuelsCan produce high-quality steam

Disadvantage:Slow start-up time

*Sources: NREL. “Gas-Fired Distributed Energy Resource Technology Characterizations.” Office of Energy Efficiency and Renewable Energy (2003), Table 1, page 1-5; U.S. Environmental Protection Agency. “Catalogue of CHP Technologies.” Combined Heat and Power Partnership (2002).

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Heat Consumers

Steam for an industrial process

Space heating

Water heating

Space cooling (absorption/adsorption chillers)

Dehumidification (using desiccant)


Steam turbines in CHP –Backpressure or Condensing

Backpressure:Constant steam demand at baseload operation Lower Capital expenditure

Condensing:Higher electrical outputHigher overall efficiencyCondensing plant required

Extraction Condensing

District Heating Condensing

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Sankey diagram


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Typical CHP Applications –Industry based

Chemicals:30, 16, 6 bar steam lines (backpressure)

Sugar:Steam line at 2.5 bar (backpressure or extraction)

Paper:Steam lines at 20 bar and 3 bar

Pulp:Steam lines at 12 and 4 bar


Biomass Energy Production Key Factors

Steam turbines are well suited to medium and large scale industrial applications where inexpensive fuel (like coal, biomass, wastes, byproduct fuels...)

Electricity – key energy product from biomass,

Steam turbine biomass plant productsElectricity

Condensing turbines (exhaust steam cooled by water from river, from closed circuit, or by air)

Combined heat + electricityExtraction condensing turbines (extraction steam used in process)Backpressure turbines (exhaust steam used for district heating, or in process)

Because of relatively high Rankine cycle cost: high annual capacity required - high reliability, availability (proven modular concept, packaging)high efficiency of energy conversion required (MRB, customized steam path)low manpower cost (automation)

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Boost factors

EfficiencyHigh inlet steam temperature, reheating of steamLow exhaust pressureHigh turbine speedHigher inlet pressure does not bring too much !!!

ReliabilityProven conceptProven componentsQuality control system including sub-suppliersQuantity of produced units

AutomationFull remote controlSuitable supervisory system


Pros and Cons

Proven steam turbine technology

Low maintenance cost

High reliability (above 98 %)

High availability (above 97 %)

Life time exceeding 200 000 operation hours

Higher investment cost

Decreasing efficiency with decreasing size of units

Efficiency lower compare to large fossil units

Unstable legal conditions in some countries

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MULTISTAGE TURBINES

• Suitable for higher enthalpy drop and higher power output

• Good efficiency in wide range of load (flat characteristic)

• Higher investment cost• Medium-time return of

investment• Higher output = higher profit

SINGLE-STAGE TURBINES• Suitable for lower enthalpy drop

and lower power output• Lower efficiency in full range of

load

• Low investment cost• Short-time return of investment

0

20

40

60

80

100

0 0,2 0,4 0,6 0,8 1

flow rate (m actual/m max)in

tern

al e

ffici

ency

(%)

Singlestage or Multistage Turbines


Economic Potential

Sensitive to:Fuel costsElectricity priceCAPEXSubsidies

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Example of Biomass Plant –Monopoli, Italy


THE FUNCTION PRINCIPLE OF RECOVERY ISLAND

LIME KILN

WOODDEBARKING CHIPPING BLEACHING DRYING BALING

PULPCOOKINGWASHING

FIBER LINE INTERNAL

BLACK LIQUERCIRCULATION

BLACK LIQUER

• REMISSED WOOD MATERIAL 10 %• COOKING CHEMICALS 5 %• WATER 85 %

BLACK LIQUEOR • WATER CONTENT 15 %

DISSOLVING TANK

FILTRATION

DREG•WOOD ASH( 5 kg / ADt )

CAUSTIZATION

RECOVERY BOILER

CHIMNEY GAS + FLY SALT

•Na2so4

WATERSOAP TALL OIL PLANT

( 50 kg / ADt )

EVAPORATION PLANT

FIBER LINE

Turbo Generator

Process steamElectricity

Steam

Electrostatic precipitators

Salt•Na2so4

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Example of CHP – Pulp and Paper mill – Wisapower, Finland

Requirements from pulp & paper process

Live Steam: 95 bar/498 °Cmax 240 kg/s

Process steam lines:

Soot blower and air heater for recovery boiler at 30 bar

Process steam and preheaterat 12.5 bar

Process steam at 7.0 bar

Process steam and deaeratorat 4 bar


Main Components – Condensing Steam turbine

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Package condensing turbineintegral oil system in baseframe and condenser

foundationcondenser



foundationcondenser

condenser

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foundationcondenser

condenser

skidcondensate

pumps



foundationcondenser

condenser

skidcondensate

pumps

skid steamejector

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foundationcondenser

condenser

skidcondensate

pumps

skid steamejector

foundationturbo set



foundationcondenser

condenser

skidcondensate

pumps

skid steamejector

foundationturbo set

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foundationcondenser

condenser

skidcondensate

pumps

skid steamejector

foundationturbo set

base frameintegral oil

system



foundationcondenser

condenser

skidcondensate

pumps

skid steamejector

foundationturbo set


system

steamturbine

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foundationcondenser

condenser

skidcondensate

pumps

skid steamejector

foundationturbo set


system

steamturbine

gear box



foundationcondenser

condenser

skidcondensate

pumps

skid steamejector

foundationturbo set


system

steamturbine

gear boxequipmentoil system

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foundationcondenser

condenser

skidcondensate

pumps

skid steamejector

foundationturbo set


system

steamturbine

gear boxequipmentoil system

generator



skid steamejector

steamturbine


system

equipmentoil system

skidcondensate

pumps

condenser

gear box

generator

foundationcondenser

foundationturbo set

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Package turbine Backpressure Turbine


foundation

Package turbine SST - 300

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foundationspring

elements



foundationspring

elements

base frame


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foundationspring

elements

base frame

oilequipment



foundationspring

elements

base frame

oilequipment

steamturbine


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foundationspring

elements

base frame

oilequipment

steamturbine gear box



foundationspring

elements

base frame

oilequipment


generator


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foundationspring

elements

base frame

oilequipment


generator

gland steamcondenser



foundationspring

elements

base frame

oilequipment


generator


pipe work


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spring elements

oilequipment

pipe work

steamturbine

foundation

base frame


generator

gear box



Thank You!

Steam Turbines with Biomass fuel

Documents

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