brown coal and biomass gasification - tu-freiberg.de · 2018-04-17 · energy, fuels and reaction...

Brown Coal and Biomass Gasification Research at Monash University Chemical Engineering

Energy, Fuels and Reaction Engineering Research GroupOur focus:Scientific R&D for Practical Solutions

Sankar Bhattacharya


Victorian brown coal

• Victoria – estimated resource• Gippsland – 394 billion tonne• Otway – 15.5 billion tonne • Murray basin – 19.5 billion tonne

• potentially economic at this stage – 33 billion tonne•Current usage

• 64-67 million tonne/year for power generation • 6555 MW capacity

• 50-70000 tonne /year for briquette production• cogeneration

GDSE – 23 -29 MJ/kgNDSE – 6-13 MJ/kg

Efficient and economic drying is key to their commercial use


Quality of lignites worldwide : moisture and ash content

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0 5 10 15 20 25 30ash content of raw coal, %

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High-ash and/or High-moisture containing coals (often termed as lignites) – their location, and calorific values (LHV, Mj/kg); country labels as follows:1: Victoria; 2: Indonesia; 3: India; 4: USA (Texas, North Dakota); 5: Germany; 6: Greece; 7: Spain; 8: Poland; 9: Czech Republic; 10: China; 11: Turkey; 12: Romania Source: various; IEA, 2010

Research on gasification

Follows on from significant prior work in coal gasification in:

• Laboratory scale, bench scale and PDU scale -1.6MW scale

• Air-blown and oxygen-enriched air blown – first -of -its -kind in Australia• Pressurised and atmospheric• Fluidized bed • Transport reactor – carried out in North Dakota with USDOE support

• Victorian, South Australian, and North Dakota lignites


Some of the brown coals used in our projectsLochiel

coalChar Yallourn

coalMorwell

coalLoy Yang

coalMoisture, %wt 60.3 7.1 62 59 59Ultimate analysisDry basis, %wtCarbon 58.2 92.4 66.1 69.3 69.6Hydrogen 4.4 0.8 4.7 5.1 5.2Nitrogen 0.52 0.7 0.61 0.64 0.64Oxygen 18.2 1.9 26.2 22.2 22.7Sulfur 3.5 0.23 0.26 0.26 0.29Ash 15.7 4.0 2.08 2.5 1.6Sodium 1.02 0.12 0.06 0.09 0.07Chlorine 0.49 0.02 0.06 0.04 0.06Ash analysis, %wtSiO2 31.40 4.35 2.48 3.21 21.20Al2O3 8.30 3.39 4.03 4.14 26.71Fe2O3 4.05 43.58 46.29 11.91 5.51TiO2 0.48 0.11 0.14 0.21 0.75K2O 0.30 0.33 0.57 0.37 0.21MgO 8.58 14.42 15.29 17.19 9.25Na2O 8.68 4.24 6.20 5.07 9.46CaO 9.97 11.77 11.88 35.63 4.99SO3 27.54 17.81 13.02 22.16 21.82LOI 0.70 0 0.10 0.10 0.10

Volatile matter ~ 50%, low-sintering pt minerals, compounds of catalytic elements, 5-10% of the coal are woody in character

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Large Scale Gasification Trials


Pressurized High Temperature Winkler (HTW) Fluidized bed gasifier -Victoria Pressurized Transport Reactor – North Dakota

• Loy Yang, Morwell, Yallourn, Lochiel• Air-blown and Oxygen-enriched air blown• 1bar and 10 bar• 1 kg/hr to 300 kg/hr• 800 – 950C

Significant work done by HRL in air-blown mode as part of IDGCC development- results publicly unavailable

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Schematic of the HTW Gasifier


DriedCoal

Fuel Gas

Flue Gas

Clean Fuel Gas

N2

N2

N2

Steam (4 levels)Air/O2 (5 levels)

N2

Gas Cooler

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Photograph of the HTW Gasifier Facility

Energy, Fuels and Reaction Engineering Research GroupOur focus:Scientific R&D for Practical Solutions 8

Courtesy – HRL Ltd

HTW trials – major objectives


Effects of:coal type – Loy Yang, Yallourn, Morwell, Lochiel, two North Dakota lignites Bed temperature and bed height Gas composition including NH3, HCN, S-compounds Carbon-conversion Steam addition Air-blown and Oxygen-enriched air-blown Characteristics of bed char and filter fines

Assessment of :fouling and agglomeration – SEM/EDS, Xray-mapping, Xray diffraction, Thermo-mechanical analysis,

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Key Results

C – conversion75-87% for Victorian brown coals, 75-83% for SouthAustralian ligniteCoarser feed and/or “briquetted coal” resulted in the higher values in the above range

Factors affecting C-conversion Coal type (reactivity, attrition resistance) Concentration of fines (<100 micron) in feed coal Elutriation of fines, originally present in coal and fines generatedCoal feed rate and reactant (steam, O2, CO2) concentration, P, T Bed drainage – bed level control – a must for FB gasifiersRecirculation of fines – cyclone efficiency, pulsing and purge in the recirc legLow ash brown coals – C-conversion limited by elutriation

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Key Results – Fuel gas

• majority of the alkali in char or filter fines

• No tar observed during steady state measurement period

• Gas composition (VIC and SA lignites) – as measured• Air-blown

• 11-15% H2, 10-20% CO, 0.7-2.5% CH4, ~1% C2Hy, 10-16% H2O• 2.7-4.1 MJ/kg• Up to 1600 ppm NH3, 100 ppm HCN, 100 ppm COS• ~3000 ppm H2S (Lochiel) without dolomite, <50ppm with dolomite (Ca/S

molar ratio = 2)• No detectable sulphides during Victorian lignite based tests• Use of dolomite also reduced NH3 levels by ~50%

• O2-blown (O2-enriched air)• 15-24% H2, 15-24% CO, 1-4 CH4, >1% C2Hy, 10-18% H2O• 3.5-5.6 MJ/kg LHV• Higher levels, up to 1800 ppm NH3, than air-blown tests

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Bhattacharya, PSEP, 2006


Tests in Transport Gasifier - collaborative project with USDOE /

UNDEERC - temperature 900C, solids velocity ~10 m/s

C – conversion• 77-83% for Loy Yang coal• 72-74% for Lochiel coal• low values due to too much fines generated

• cyclone problems

Dry gas composition – Loy Yang• air blown

•18% H2, 12% CO, 4% CH4, 18% CO2, 47% N2• O2-enriched air blown

• 26% H2, 17% CO, 8% CH4, 40% CO2, 8% N2

Dry gas composition – Lochiel• air blown

•13% H2, 10% CO, 3% CH4, 20% CO2, 55% N2• O2-enriched air blown

• 33% H2, 12% CO, 8% CH4, 39% CO2, 7% N2

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Projects on Entrained Flow Gasification - brown coal and biomass


• Entrained flow gasification : 1000C- 1400C• particle fragmentation behaviour• gasification characteristics• gaseous emission• trace elements emission

J. Tanner et al. / Fuel 154 (2015) 107–113Xu et al., Proc Clearwater Conf, 2015

• Slag characterisation and viscosity behaviour• experiments and modeling• mineral transformation• Combination of Phase diagram, Ash fusion DTA and Synchrotron XRD

S Srivatsa et al. / forthcoming

• Alkali, S and Cl emission in-situ at high temperature• Molecular beam mass spectrometry measurements

J. Tanner et al. / Fuel 158 (2015) 72-80J. Tanner et al. / Energy & Fuels 28 (2014) 6289-6298


Entrained flow reactor and Viscometer assembly

Gasification results


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Yallourn char

20% CO2

For complete conversion24s is required, 1000 OCCompared with theoretical model

1000 OC pyrolysis char

1000 OC 12 s gasification char

1000 OC 24 s gasification char

Gasification results


Particle fragmentation

Measured at the end of varying residence time, and varying temperature

106-125 µm particle fragments into ……..

5 – 90 µm

…..has effect on residence time and ……..hence C-conversion

Viscosity of slags


Viscosity measurements preceded by DTA and in-situ XRD experiments

Victorian brown coal ash vary enormously in composition

SiO2 : 10 - 60% Fe2O3 : 5 - 50%Al2O3 : 5 – 30 % CaO : 5 – 40%

Some models work for high Fe/low Ca ash…………..

……for high Ca/Na ash, the models fail------ for Yallourn ash : >1460 for 100-250 poise------ for Loy Yang and Morwell – blending with Yallourn required

Implication for the gasifier configuration


Char

Endothermic gas temperature profile

Low Temp High Temp

Acknowledgements


Joanne TannerTao XuSrikanth SrivatsaMahmud KibriaPramod Sripada

Dr Michael MüllerDr Mark Bläsing

Our major current research projects

Oxy-fuel combustion – pf and Fluidized bed

Entrained-flow gasification -brown coal and agro-forestry

residues)

Brown coal and biomass for application in Direct Carbon Fuel Cell

LCA for Ni and Cu resource companies

•Combustion and gasification using “chemical looping”

•Kinetics of steam and flue gas drying of fine particles of brown coal

•DME/Methanol synthesis from dried brown coal, wastes and biomass

• Co-processing of algae, dried brown coal, sewage sludge

• Liquid fuels from waste plastics


Funding and partners: Brown Coal Innovation Australia, DRET, ANLEC R&D, CSIRO, Alstom, MHI, JSW, Thermax, Energy Australia

brown coal and biomass gasification - tu-freiberg.de · 2018-04-17 · energy, fuels and reaction...

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