isbuc third meeting mauritius 29 june – 3 july 2009

Centre for Tropical Crops and Biocommodities

Sugar Research and Innovation

International Sugarcane Biomass Utilisation Consortium

ISBUCThird meeting

Mauritius29 June – 3 July

2009

The feasibility of implementing gasification technology in the sugar

industry; an Australian perspective

P.A. Hobson




The feasibility of implementing gasification technology in the sugar industry;

an Australian perspective

□ Gasification – initial interest- Drivers- Preliminary studies

□ Queensland Biomass Integrated Gasification program- Development of the business plan- Outcomes from the QBIG program- Subsequent work

□ Current directions- Pre-processing of bagasse (torrefaction)- Second generation biofuels




Gasification – some preliminary studies□ Early 1980s – Tests commissioned on

catalytic gasification for methanol production (Battelle Labs, US)

□ Renewable Energy (2000) Act- Mandated 2% new renewable(9500 GWhe)

capacity by 2010 continuing to 2020- $40 per MWh penalty for not meeting

renewable power targets□ Preliminary SRI study on integrating

gasification and factory operations (1998)- Two-fold increase in power generation

relative to conventional steam- Precursor to Queensland Biomass

Integrated Gasification project - Australian milling industry and Sugar

Research and Development Corporation




Preliminary study- impact of factory process steam (2 M tonne crop)




Preliminary study- impact of additional fuel on power generation efficiency




Preliminary study- year round power generation with additional fuel from trash

(2 M tonne crop)

Crushing season□ Minimum bagasse

consumed to meet process demands

□ Sufficient surplus bagasse/ trash stored to fully utilise gasifier and GT in off-season

Off-season□ All stored bagasse

consumed




Preliminary study- whole of (Australian) industry export capacityCrop size 37 M tonnes

Scenario Additional fibre from

trash(% original bagasse)

Crushing season export

capacity(MWe)

Off-season export

capacity(MWe)

Annual power export

efficiency(%)

Base case -Steam 0 360 580 10

(1) BIG/CC 0 1045 885 22

(2) BIG/CC 23 1045 1370 21

(3) BIG/CC 66 2680 3045 37




Preliminary study - site visits□ Varnamo, Sweden

- Sydkraft- 6MWe/ 9MWth- 22 bara, CFB

□ Maui island, Hawaii- IGT technology- 100 tons/ day- 21 bara, BFB

□ Burlington, US- Battelle technology- 200 tons/ day- 2 bara, indirect CFB

□ Morwell, Australia- HRL technology- 5 Mwe GT- 25 bara, CFB




Preliminary study – HRL IDGCC (brown coal) technology

NITROGEN

LOCKHOPPERPRESSURISATION

COAL

BUFFER / WEIGHINGHOPPER

COOLED GAS

CLEANEDGAS

DUST

FILTER

COMBUSTOR

COM

PRES

SOR

AIR

TURBINE

EXHAUST GASES

WATER PUMP

CONDENSER

ALTERNATOR

TURBINE

BOIL

ER

STEAM

STEAMTURBINE

HEAT

RECOVERYGAS

TURBINECLEANINGGASIFIERDRYER

COAL

DRIED

COAL DRYING

AND GAS COOLING

CYCLONE

AIR

AIR

HOT GASASH/ CHAR

CO2

TO STACK STEAM

ASH/ CHAR




Preliminary study – some conclusions □ Approximately 100% increase in power export□ Pressurised BIG/CC appropriate to Australian industry

- Higher capital cost offset by greater efficiency for BIG/CC installations greater than 50 MWe

- All mills would have a BIG/CC capacity > 50 MWe

□ For maximum efficiency potential- Process steam demand < 40% SOC; or- An additional 25% fibre

□ Pressurised feeding of bagasse is problematic- Low bulk density compared with other biomass- Bagasse ‘binds’ in screw feed systems

□ Large amount of additional fibre to fully utilise capacity in off-season - Additional 66% of existing bagasse supply- Approximately 350,000 tonnes storage for 2 M tonne factory




Development of the QBIG program□ Project team

- Formed prior to development of scoping study- Team members:

▪ Power Industry - Stanwell Corporation Ltd▪ State Government – Office of Energy▪ R&D providers – SRI, University of Queensland

□ Scoping study/ business case- Critical assessment of conversion technologies- Evaluation of power export potential and GHG mitigation- Fully costed research plan- Study externally reviewed

□ Secured funding- A$ 5m- Power industry and State Government




Queensland Biomass Integrated Gasification program (QBIG)

□ Initiated in 2000□ Ultimate aim of commercial demonstration of high

pressure BIGCC□ Phase I – Strong focus on sugar industry specific

feasibility issues- Bagasse gasification kinetics- Pressurised feeding- Ash characterisation- Fuel availability- Financial viability

□ Phase II - Demonstration




QBIG – Gasification kinetics

□ Focus on char- Initial char yield- Subsequent char

gasification rate

□ Bench scale reactor

- 900 °C- 25 bara- Entrained flow- Departure from TGA- Computational Fluid

Dynamics (CFD) model- Implementation of char

reactivity data- Assist Phase II design




QBIG – Pressurised feeder

□ Design criteria:- High volume- Continuous- High pressure- Sealed

□ Bagasse particularly difficult to feed!

□ Continuous feeder developed- Tested to 25 barg- Minimal leakage with

bagasse- Leakage problems with

bagasse/ woodchip blend- Demonstrated at 75% of

15 MWth commercial demonstration scale




QBIG – fuel availability

□ Whole of cane biomass harvesting

□ Factory separation□ QBIG separator:

- Demonstrated at commercial scale (150 tch)

- Low cane losses (< 1%)- High trash recovery (98%)




QBIG – Financial viability

Options Total capacity

(MW)

Net energy export (GWh)

Total capital ($A million)

IRR (%)

1. Steam base case 66 180 74 14

2. Option 1 + 80% trash 156 495 126 14.2

3. BIG/CC +80% trash (10 month operation)

155 829 203 16.6

□ Multiple scenarios - factory integration, fuel and operational □ Conventional steam and IG/CC compared□ Conversion of existing boiler to HRSG reduces capex for IGCC□ Steam plant dominated by fuel costs, IG/CC by capital costs□ Figures below based on 2000 – 2002 costs & revenues (very

different now!)




QBIG – Outcomes

□ Phase I- Essentially complete- Ash characterisation deferred to phase II

□ Phase II- Australian renewable energy target scheme inadequate

▪ Value of RECs lower than anticipated● Initial projections of A$40 per MWh● Actual value dropped to A$16 per MWh

▪ Bid at the time to increase 2% federal target to 5% rejected

- Escalating capital costs - Decision by main stakeholders not to proceed




Integration of gasification in the Australian sugar industry

□ Major feasibility study- Federal and Queensland state funded Sugar Industry

Renewable Energy program- Industry-wide staged introduction- Technical and financial analysis

□ Some findings include:- Confirms QBIG economic study- Optimum mix of conventional and IG/CC power would deliver

66% of the federal renewable target of 9500 GWh- Capex 2.8 times conventional steam - a major impediment- High cost of trash at A$15 - A$25 per tonne reduces IG/CC

viability- Lapse of federal governments renewable energy target in

2020 provides insufficient revenue certainty for emerging technology




19/18

Current directions – what’s changed?□ Mandated Renewable Energy Target

- Originally 9,500 GWh new capacity- Extended to 45,000 GWh by 2020

□ Carbon Pollution Reduction scheme- Implementation by 2010- Emissions reduction relative to 2000

▪ Long-term target – 60% by 2050. ▪ Medium-term – 5% to25% by 2020.




Current directions□ Diversification - value adding to fibre□ Current projects at QUT - fuel and chemicals

- Flash pyrolysis for furfural production- Biorefinery demonstration plant

▪ Ionic liquids for fractionation▪ Value adding to lignin▪ Hydrolysis of cellulose to C6 sugars – fermentation to ethanol

- Direct liquefaction of bagasse▪ Hydrothermal liquefaction for bagasse fractionation▪ Phenolic compounds from lignin▪ Levulinic acid from cellulose

- Torrefaction▪ Use of catalysts to reduce residence time▪ Impact of pre-processing on supply chain logistics and costs




Gasification technology□ Flexible – power, fuels, chemicals□ Efficient

- Power export increased by factor of 2.5- 330 L ethanol per tonne dry fibre- 140 L diesel per tonne dry fibre

□ Issues- Lack of commercial demonstration- Economies of scale- Material handling

▪ Transport▪ Large scale storage▪ Feeding




Torrefaction as a pre-process - strategic advantage

□ Coal-like energy density and handling properties□ Capitalises on decades of coal technology

development- Synergies with short and long term development

horizons- Conventional power generation (co-firing)- Advanced cycle power generation (IG/CC, pressurised

combustion)- Coal to liquid fuel production (Fischer Tropsch

hydrocarbons and alcohols)- Emerging technologies (supercritical gasification, direct

liquefaction, hydropyrolysis)□ Low technical and commercial risk

- Engineering challenge ‘reduced’ to development of a low pressure/ temperature pre-process

- Utilisation of significant existing coal R&D facilities




The torrefaction process□ 200° - 300°C□ Near atmospheric

pressure□ Absence of air□ Residence time of

10 – 30 mins□ Volatilisation of

hemicellulose component

□ Feedstock thickness < 4cm

□ Heating rate <50°C/min

Torrefaction100

100

70

30

90

10

Energy densification = 1 x90

70= 1.3

Mass Energy

torrefied productdry biomass

off-gas




Torrefied biomass□ Typically 24 MJ/kg (HHV)□ Hydrophobic (maintains ~3% moisture)□ Stable in long term storage□ Friable

- 10% of the comminution energy required for untreated biomass

- Compatible with conventional coal milling equipment□ Readily pelletised

- 50% of energy required to pelletise raw biomass- High residual lignin (bonding agent)

□ Volatiles retained- 50% to 60% volatiles retained- Rapid combustion/ gasification- A “smokeless” fuel




25/1

Comparison with other pre-processes

□ Supply chain study by Uslu (et al., 2008)

□ Process efficiency- Torrefied and then Pelletised Bagasse

(TPB) - 94%- Pelletised biomass - 84%- Bio-oil (from flash pyrolysis) - 64%

□ Cost of biofuel production using TPB- 86% of cost using pelletised biomass- 63% of cost using pyrolysis




Comparison of pelletised torrefied biomass (TOP) with pelletised and unprocessed biomass1

1Kiel, J. (2007) IEA Bioenergy Task 32 workshop “Fuel storage, handling and preparation and system analysis for biomass combustion technologies”, Berlin



International Sugarcane Biomass Utilisation ConsortiumPreliminary financial evaluation

FT Diesel

Mill A

Mill B

Mill C

Mill D

Mill E

Bagasse stockpile Torrefaction plant

0 km

55 km

110 km

165 km

220 km

BTL plant

Year-round operation

Maintenance season

Crushing season

Mill A

Mill B

Mill C

Mill D

Mill E

Fischer Tropsch (FT) diesel

Biomass to liquid fuel (BTL) plant

Torrefaction plant

110

55

165

220 km

Year round operation

Crushing season

Maintenance season




Torrefaction - material inputs

Mill A Mills B to E (per mill)

Cane (tonnes) 2,200,000 1,100,000

Surplus bagasse (tonnes) 285,000 143,000

Bagasse storage (tonnes) 165,000 82,000

Crushing season (hours) 3,600 3,600




29/18

Torrefaction - financial inputsMill A Mills B to E

(per mill)

Capital cost (A$m) 33 19

Operating and maintenance (A$m) 3.1 1.7

Project hurdle rate (%) 15 15

Project life (years) 20 20




Storage & transport costs

0

10

20

30

40

50

60

70

80

90

55 110 165 220

Distance of mill from biofuel plant (km)

Sto

rag

e &

tra

ns

po

rt c

os

ts (

$/

ton

ne

) Raw bagasse

Bagasse equivalentof torrefied product

Mill B Mill C

Mill D

Mill E




Gasification and biofuel production□ Conversion efficiencies (energy basis)

- Biomass to syngas – 80%- Syngas to FT diesel – 71%

□ Capital cost based on Boerrigter (2006)□ Assumed same as CTL1 costs after pre-processing□ CTL estimated by inflating known GTL2 costs

- Additional reactor costs- Additional oxygen enrichment

□ Operating fixed percentage of capex□ Assume long term 50% excise discount or equivalent

for renewable fuels

1CTL – “Coal to liquid fuels”; 2GTL – “Gas to liquid fuels”




Diesel production costs

1.00

1.05

1.10

1.15

1.20

1.25

1.30

1.35

1.40

Mill A A+B A+B+C A+B+C+D A+B+C+D+E

Mills from which feedstock is sourced

Co

st

of

FT

die

se

l pro

du

cti

on

($

/L)

1.00

1.05

1.10

1.15

1.20

1.25

1.30

1.35

1.40

0.00 1.00Bagasse transport

Pre-transport torrefaction

Diesel price to bowser at 97 US$/ bbl

Diesel price to bowser at 76 US$/ bbl




Impact of pre-processing on gasification costs

□ TPB has lower transport costs than bagasse for distances greater than 100 km

□ Break-even (15% IRR) oil price for diesel production - 97 US$/ bbl without local TPB production and transport- 76 US$/ bbl with local TPB production and transport

□ Potential for further reduction in costs- Accessing TPB from greater distances (i.e. > 200 km)- TPB from biomass sources other than bagasse- Co-firing in CTL plants (e.g. SASOL)- Integration of advanced cycle power plants (IG/CC)




In conclusion ...□ Development of a good business case – worth doing well

but can be a costly process□ Ideally syndicate members should be identified prior to

preparation of the business case□ Peer review prior to issue□ Robust financial analysis investigating key drivers□ Look for highest value end product□ Focus RD&D on sugar industry specific issues□ Should be technically well differentiated from other/

previous projects□ Minimise technical risk - look for opportunities to utilize

proven/ commercial technology




Acknowledgements

□ Compagnie Sucrière du Sud and Queensland University of Technology for their sponsorship

□ Jean Claude Autrey and Manoel Regis Leal for the invitation to attend this meeting




Thank you

isbuc third meeting mauritius 29 june – 3 july 2009

Documents