Innovative use of Integrated Gasification Combined Cycle...Hot air plus wood chips –exothermic,...

Innovative use of Integrated Gasification Combined Cycle

Evolving an economically viable biomass power solution

R John Thomas

Laura Fell

Environmental Energy Australia Pty Ltd &

Fleurieu Power Company Pty Ltd

Power Plant design evolution• In 2016 EEA responded to “Non Network Options Report” for Kangaroo Island

• Proposed a combustion / steam turbine solution for power plant

• Expensive in terms of use of fuel, needed subsidy to work economically

• Costs of ash management

• Top ranked of all “non network” credible responses to the NNOR

Environmental Energy Australia Pty Ltd &Fleurieu Power Company Pty Ltd

Biomass as a fuel

• Massive moisture content• At times higher than 50% water;

• Means that much of the combustion energy simply evaporates water.

• Bulky material with moderate calorific value• Need many tons of wood chip to make 1 MW hour of power 24 hours a day,

365 days a year;

• Large materials handling issue.


Economic & other concerns

• Rate of change of power plant output;

• Network needs rapid demand response;

• In SA at least MUST bring “inertia” to the network;

• Needs to be environmentally friendly; • Low or non existent particle emissions;

• Low NOX, SOx

• Acoustically acceptable.

• Reliability of power production, meet the National Electricity Rules


Dry the biomass-Torftech Compact Bed Reactor

Wood chips from 50% to 15% moisture, then suitable for syngas generation.

Use waste heat from HRSG exhaust to dry the wood chips.


Create Syngas -Torftech Expanded Bed ReactorHot air plus wood chips – exothermic, stoichiometry limited O2

Hot gas to cycloneHot gas then to air /gas heat exchanger, heat up incoming air.

Syngas H2, CO, CH4, N2

Low calorific value syngasGas quite dirty

Nutrients in biochar, no ash for disposal. Environmental Energy Australia Pty Ltd &Fleurieu Power Company Pty Ltd

Options to use low Calorific Value syngas

1. Burn syngas, raise steam in boiler, use steam turbine generator1. Around 20% - 30% thermal efficiency.2. Lag in turn down / ramp up.

2. Heat an organic Rankine cycle turbine1. Around 14 - 18 % thermal efficiency.

3. Gas spark engine1. Around 30% - 40% thermal efficiency, was in use at Usk (Wales) but maintenance issues.2. Need serious gas clean up plant .3. High maintenance for any reciprocating engine.

4. Gas turbine1. Aero-derivatives 40% efficiency plus; but poor ride through, need clean fuel2. Heavy duty “Frame” units tolerate dirty fuel, massive power system disturbance ride

through, 28% - 32% efficient, Frame 5 in particular is responsive.

3. Add Heat Recovery Steam Generator – use energy in Gas Turbine exhaust1. Thermal efficiency to around 45% - 50% but less responsive than Gas Turbine.


RDFdrier

HRSG Exhaust to driers

RDF Gasifier

Gascooling

Dry RDF

Hot Syngas

Extra steam to HRSG system

Gas scrubber

Syngas compressor

Gas cooling

Gas clean up

Gas in pipeline – line pack

Gas Turbine & Generator

To HV switchyard

11kV

Steam Turbine & Generator

Buried length of gas pipeline

Oxygen System

Air in

RDF in

Captured contaminantsCaptured

contaminants

Water, grit

Cool syngas

Cool clean compressed syngas

Gas Turbine &

GeneratorRDP pre-prepared offsiteOxygen by Pressure Swing AdsorptionMultiple drier / syngas / scrubber trainsTwo or three Gas turbine generatorsSingle HRSG Wastes captured in biochar and at scrubber

Hot Syngas


Plant schematic – RDF as fuel

TORBED®

Gasifier

Char

Feed Surge

Bin

Start up

Burner

Process Air

Fan

Char

Cyclone

Recycle Fan

Dry RDF

Gas

Buffer

Gas

Flare

Outlet

Cleaning Medium

Syn Gas

Booster Fan

GeneratorGas Turbine

Compressor

Excess heat

Heat Recovery

Steam Generator

`

TORBED

Dryer

Oxygen

Wet RDF

Gasifier Module

Gas Cleanup

SteamTurbine Generator

Dryer Module

Powerhouse


Plant layout

• Woodchip in, to drier.• Drier runs on HRSG

exhaust• Chips to syngas• Syngas to Frame 5 Gas

Turbine• GT exhaust to HRSG• HRSG exhaust to drier• Mass spec for

environmental monitoring.


Plant characteristics

• Three GE Frame 5-M Gas Turbine Generators at 32 MVA each

• One HRSG, associated Steam Turbine Generator at 32 MVA

• Peak output 110 MW

• Base load output• GTG-1, 2, 3 at 5 MW each, STG-1 at 12MW using approx. 28 tonnes per hour

of biomass (RDF).

• Peak to 25MW per GTG to deliver 60 MW rapid response(Raise 6)

• Approximately 900 - 1,000 MWs of inertia


Technical compliance challenges

• Suitable connection point• What voltage / MVA capacity, existing protection systems;• Typically not near the biomass!

• Meet the National Electricity Rules• Expensive modelling work to gain a connection agreement;• Flow modelling, ride through capability imperative on skinny

network.

• In SA at least, mandatory inertia requirements.

• EPA requirements• Acoustic• Atmospheric• Water


Modelled outcomes

• Power production cost • On woodchip marginal cost of production $108 / MW Hour

• Fuel - woodchip cost $78 / MW Hour

• OPEX – across green output adds $30 / MW Hour

• On RDF, assuming $20 per tonne RDF cost and ash disposal adding $20 per ton to process, marginal cost of production drops to around $80 / MW Hour or less if adequate fuel supply.

• No offset provided in figures above for value of Inertia or FCAS.

• OPEX per MWH costs driven by low base capacity – limited fuel.Environmental Energy Australia Pty Ltd &Fleurieu Power Company Pty Ltd

Acknowledgments • Kangaroo Island Council - Report on Biomass on Kangaroo Island

• Dunstan C., Fattal A., James G., Teske S., 2016, Towards 100% Renewable Energy for Kangaroo Island. Prepared by the Institute for Sustainable Futures, University of Technology Sydney (with assistance from AECOM) for ARENA, Renewables SA and Kangaroo Island Council.

• Innovation and Science Australia – R&D Tax Incentive – Lloyd Thomas Enterprises Pty Ltd & Laura Fell Management Pty Ltd

• Mr Martin Groszek, Torftech

• Fleurieu Power Company as Trustee for Fleurieu Power Unit Trust, Environmental Energy Australia Pty Ltd

Any discussion on supplier selection relates only to the Fleurieu Power ProjectEnvironmental Energy Australia Pty Ltd &Fleurieu Power Company Pty Ltd

Date post:	01-Sep-2020
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Innovative use of Integrated Gasification Combined Cycle...Hot air plus wood chips –exothermic,...

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