Brown Coal and Biomass Gasification Research at Monash University Chemical Engineering

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1 Brown Coal and Biomass Gasification Research at Monash University Chemical Engineering Sankar Bhattacharya

2 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 million tonne/year for power generation 6555 MW capacity tonne /year for briquette production cogeneration Efficient and economic drying is key to their commercial use GDSE MJ/kg NDSE 6-13 MJ/kg

3 Quality of lignites worldwide : moisture and ash content 70 moisture content of raw coal, % Mj/kg Mj/kg 12 Mj/kg 16 Mj/kg Mj/kg ash content of raw coal, % 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

4 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

5 Some of the brown coals used in our projects Lochiel coal Char Yallourn coal Morwell coal Loy Yang coal Moisture, %wt Ultimate analysis Dry basis, %wt Carbon Hydrogen Nitrogen Oxygen Sulfur Ash Sodium Chlorine Ash analysis, %wt SiO Al2O Fe2O TiO K2O MgO Na2O CaO SO LOI Volatile matter ~ 50%, low-sintering pt minerals, compounds of catalytic elements, 5-10% of the coal are woody in character 5

6 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 C Significant work done by HRL in air-blown mode as part of IDGCC development - results publicly unavailable 6

7 Schematic of the HTW Gasifier Gas Cooler N 2 Flue Gas Dried Coal Fuel Gas N 2 N 2 Clean Fuel Gas N 2 Steam (4 levels) Air/O2 (5 levels) 7

8 Photograph of the HTW Gasifier Facility Courtesy HRL Ltd 8

9 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 NH 3, 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, 9

10 Key Results C conversion 75-87% for Victorian brown coals, 75-83% for SouthAustralian lignite Coarser 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 generated Coal feed rate and reactant (steam, O2, CO2) concentration, P, T Bed drainage bed level control a must for FB gasifiers Recirculation of fines cyclone efficiency, pulsing and purge in the recirc leg Low ash brown coals C-conversion limited by elutriation 10

11 Key Results Fuel gas No tar observed during steady state measurement period Gas composition (VIC and SA lignites) as measured Air-blown 11-15% H 2, 10-20% CO, % CH 4, ~1% C 2 H y, 10-16% H 2 O MJ/kg Up to 1600 ppm NH 3, 100 ppm HCN, 100 ppm COS ~3000 ppm H 2 S (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% O 2 -blown (O 2 -enriched air) 15-24% H 2, 15-24% CO, 1-4 CH 4, >1% C 2 H y, 10-18% H 2 O MJ/kg LHV Higher levels, up to 1800 ppm NH 3, than air-blown tests majority of the alkali in char or filter fines Bhattacharya, PSEP,

12 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 12

13 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) Xu 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) J. Tanner et al. / Energy & Fuels 28 (2014)

14 Entrained flow reactor and Viscometer assembly

15 Gasification results 100 Carbon Conversion (%) o C 900 o C 800 o C 700 o C 1000 O C pyrolysis char Residence Time (s) 1000 O C 12 s gasification char Yallourn char 20% CO 2 For complete conversion 24s is required, 1000 O C Compared with theoretical model 1000 O C 24 s gasification char

16 Gasification results Particle fragmentation Measured at the end of varying residence time, and varying temperature µm particle fragments into µm..has effect on residence time and..hence C-conversion

17 Viscosity of slags Viscosity measurements preceded by DTA and in-situ XRD experiments Victorian brown coal ash vary enormously in composition SiO 2 : 10-60% Fe 2 O 3 : 5-50% Al 2 O 3 : 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 poise for Loy Yang and Morwell blending with Yallourn required

18 Implication for the gasifier configuration Char Endothermic gas temperature profile Low Temp High Temp

19 Acknowledgements Joanne Tanner Tao Xu Srikanth Srivatsa Mahmud Kibria Pramod Sripada Dr Michael Müller Dr Mark Bläsing

20 Our major current research projects Oxy-fuel combustion pf and Fluidized bed Combustion and gasification using chemical looping 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 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