Co-Utilization of Coal and Biomass - Experience in Europe

Transcription

1 Co-Utilization of Coal and Biomass - Experience in Europe Dr.-Ing. Klaus R.G. Hein Prof. em. University Stuttgart, Germany Conference on Clean Coal and Carbon Capture and Storage Technologies Tiruchirappalli India, December 2013

2 Biomass utilization Historic past: feed stock for human existence, e.g. - direct use as food, tools, cloths - indirect use as heat source Industrial age: e.g. conversion to power, chemicals etc. Early last century: Generation of transport fuels

3 Biomass utilization Wood gasifier (Germany, about 1950): Consecutive replacement of biomass by - Coal (more efficient) - Gas ( town gas, more easy to use) - Natural gas (cheaper)

4 Biomass / biogenic wastes; Renewed interest (80ies / 90ies) for various reasons: Local / regional availability Utilization of residues from agriculture, forestry Wastes from domestic / community / industrial processes Solution in case of disposal / land fill restrictions Preservation of fossil fuel resources Reduction of dependence on fuel imports Recultivation of surplus farming areas

5 The 90ies and beyond: New drivers: 1. Global climate issue Greenhouse gas emission, in particular CO 2 emission problem 2. Sustainability of energy supply Expected strong increase of energy / electricity demand at limiting access to primary energy resources Resulting actions: - Kyoto Protocol (1997) - Europe: Political commitment towards sustainable energy supply and environment protection at competitive level

6 Energy Policy of the European Union (1) towards limiting the global climate change to 2 C Strategic objective: at least 20% reduction of GHG by 2020 (50% by 2050) compared to 1990 Energy Efficiency Action Plan, i.a. Transport: fuel efficient vehicles Buildings: energy performance improvement, energy savings Electricity / heat generation: efficiency improvement,lower carbon fuel alternatives

7 Energy Policy of the European Union (2) Energy sources: Mix of all primary energy options Nuclear: 1/3 of electricity, 15% of total mix Renewables: 20% by 2020, 10% biofuels for electricity generation heating and cooling transport

8 Consequence for heat / power generation in Europe Initiation by the European Commission of: research into substitution of high carbon coal by lower carbon biomass (s.c.carbon neutral sources) through multi-partner / multi-country projects in partnership between industry, SME and academia on laboratory, pilot and industrial scale financially supported by the European Commission

9 Result: Promotion of research and development projects on - clean coal activities - biomass utilization among these: Specific co-utilization research in Europe APAS (Action de Préparation, d Accompagnement et de Suivi) 30 M Euro, 12 M Euro from EC Co-combustion: Co-gasification: 25 partners, 8 countries 18 partners, 8 countries

10 Biogenic Fuel Categories (Selection) Untreated biomass: Fire wood Forest residues Bark Saw dust Straw Road side grass Cultivated biomass: Short rotation forestry Cereals Rape Residues from agricultural industry: Nut shells Cherry kernels Sunflower hulls Rice husk chicken litter Residues from industrial processes: Demolition wood Sewage sludge Treated domestic waste (RDF) Paper pulp Pet coke Black liquor

11 Source: IEA report CCC 102

12 Co-utilization of biomass How? - simultaneous feed of biogenic fuels and solid fossil fuels Why? - reduction of local green house gas and other emissions Application? - combustion: heat / electricity generation - gasification: gas production for fuels, chemical feed stock and heat/electricity generation

13 Co-utilization in heat/power generation Benefits: Part-replacement of high carbon fuel by low carbon fuel Advantageous use of high efficiencies/low emissions of modern large coal plants Increase of biomass utilization No operational issues by low biomass percentage No continuous biomass supply required Certain process advantages due to high volatile biomass addition Capital cost advantages in comparison with mono-use of biomass Compensation of fluctuating availability of renewablen energy sources

14 Co-utilization application Technology: Two approaches: direct and indirect use - Direct: feeding to same reactor -- with same fuel preparation equipment (low biomass share 3%) -- with separate biomass pre-treatment (higher biomass feed possible) - Indirect: separate fuel conversion for coal and biomass followed by parallel or consecutive combination of both paths, e.g. : -- separate combustors, integration into one steam cycle -- biomass pyrolysis followed by combustion of gases and char in coal boiler -- biomass gasification followed by gas combustion in coal boiler -- biomass gasification followed by gas cleaning and subsequent gas combustion in coal boiler

15 University of Stuttgart Institute for Process Engineering and Power Plant Technology Director: Prof. Dr.-Ing. K.R.G. Hein Co-Combustion Methods Overfire air Fluidised Bed Reactor Productgas Waste Residues Biomas Ash Direct use Indirect use

16 University of Stuttgart Institute for Process Engineering and Power Plant Technology Director: Prof. Dr.-Ing. K.R.G. Hein Direct Co-Combustion 0-15 % biomass biomass coal biomass preparation PF % biomass CFB biomass preparation if required coal

17 University of Stuttgart Institute for Process Engineering and Power Plant Technology Director: Prof. Dr.-Ing. K.R.G. Hein Indirect Co-Combustion biomass pyrolysis gas char preparation coal biomass gasifier gas cleaning ash coal biomass biomass washing coal

18 University of Stuttgart Institute for Process Engineering and Power Plant Technology Director: Prof. Dr.-Ing. K.R.G. Hein Comparison of Investment Costs (about 2000) 1600 Investment costs in DM/kWth Biomass only Co-combustion in coal fired power plants Kaisersesch Lübbenau Ulm Nijmegen Arhus St. Andrä Straw Wood

19 University of Stuttgart Institute for Process Engineering and Power Plant Technology Director: Prof. Dr.-Ing. K.R.G. Hein Possibilities of Co-Combustion Co-Combustion of Waste Materials Power Plants Industrial Processes coal fired gas /oil fired energetic use us of material and material properties pulverized fuel blast furnaces (blast furnaces) wet bottom dry ash fludized bed tile / brick production cement kilns tile / brick production metal production asphalt production stoker firings Energetic Use Use of Material Properties

20 Handling of straw 4 tonnes straw per hectare 500 kg big bales 24 bales on each truck 20

21 Co-firing of straw in a coal-fired power plant (DK) Straw handling plant Combined coal/straw burner

22 SRF Co-combustion at the Weisweiler Power plant Pulverised fuel firing system 2 x 600 MW el

23 Steam generator Unit G +H, Weisweiler Steam data : 525 kg/s 530 ºC 173 bar Fuels : Lignite Paper sludge SRF (test) Boiler efficiency: 87,1%

24 Co-combustion of SRF at the Weisweiler Power Plant

25 SRF co-combustion at the Berrenrath co-generation power plant CFB combustion system 2 x 235 MW th

26 SRF- and Sewage sludge co-combustion at Berrenrath cogeneration power plant Sewage sludge Further flue gas clean-up with Pulverized lignite coke Run-ofmine lignite SRF

27 Avedøre power plant unit 2 (DK)

28 Gas production from solid fuels: Historically by thermal decomposition of solid fuels (wood, later coal) for e.g. lightning, heating, cooking More recently by steam / air / oxygen-supported gasification for power generation in motors / turbines In combination with additional gas conversion processes for production of liquid fuels and feed stock for chemical industries

29 Why biomass gasification? Part-utilization of biogenic fuels in large scale heat / power generation No restrictions of main boiler operation / availability by biofuel system No quality change of main boiler ash

30 University of Stuttgart Institute for Process Engineering and Power Plant Technology Director: Prof. Dr.-Ing. K.R.G. Hein Gasification / Pyrolysis for advanced Reburning Overfire air Fluidised Bed Reactor Productgas Waste Residues Biomas Ash

31 Fluidized bed gasifier Product gas Product gas Cyclone Biomass Freeboard Cyclone Biomass Fluidized bed Fluidized bed Ash Ash Air Ash Bubbling Fluidized Bed Air Ash Circulating Fluidized Bed

32 Biomass plant Güssing (A)

33 Power Plant Lahti (FIN) Biomass 300 GWh/a -15 % fuel input 350 MW 540 C/170 bar CO 2 Reduction - 10 % Processing 50 MW Pulverized coal flames Power * 600 GWh/a District Heat * 1000 GWh/a Gasifier Gas flame Bottom ash Coal Natural Gas 1050 GWh/a -50 % 650 GWh/a -35 % Fly ash

34 Amer Power Station (NL) ttp:// Wim_Willeboer_-_Essent_.pdf

35 Biomass utilization, shortcomings Restricted seasonal availability (mass, quality, variability) Low energy density, high output-specific requirements High fuel and preparation costs Potential problems during operation

36 University of Stuttgart Institute for Process Engineering and Power Plant Technology Director: Prof. Dr.-Ing. K.R.G. Hein Areas of Concern air pre - heater 3 2 ESP FGD Mill: Wear, capacity 2 Combustion chamber: Slagging, fouling 3 Superheater: Fouling, corrosion 4 Conv. heat exchangers: Fouling, errosion 5 DeNO X -catalyst: Deactivation, capacitiy, errosion 6 ESP: Dust composition, capacity 7 Ash: Use / disposal 8 FGD: Capacity 9 FGD: Use of by-products 10 Stack: Emissions

37 University of Stuttgart Institute for Process Engineering and Power Plant Technology Director: Prof. Dr.-Ing. K.R.G. Hein Ash Fusion Characteristics 1550 european hard coal wood samples different straw samples 36 samples miscanthus sinensis energy crop standard deviation and mean value 1300 temperature [ C] softening to hemispherical (ST-HT) hemispherical to fluid (HT-FT)

38 Fouling of superheater area

39 Circulating Fluidized Bed Firing System Combustion chamber with nozzle grate

40 Plugging of the nozzle grate after one of the first SRF co-combustion periods Note: Situation has been improved significantly

41 Analysis of corroded superheater tubes after a previous period of SRF co-combustion

42 Obstacles for co-utilization Data about fuel supply and quality Fuel cost Impact of new supplemental fuels on system Use of the fly ashes impact on quality legislation Extensive permission requirements Liberalisation of the electricity market

43 Coal-biomass co-utilization, research and application in Europe Overall outcome: Co-utilization is - environmentally beneficial - technologically feasible - economically attractive

44 Co-utilization activities in Europe (selection) Source: IEA report CCC 102

45 Status of co-utilization in Europe More than 100 demontration projects in Europe, some still in operation Major overview reports available, e.g. by IEA: - CCC60 (2002) Prospects for co-utilisation of coal with other fuels GHG emissions reduction - CCC102 (2005) Fuels for biomass cofiring - CCC158 (2009) Co-gasification and indirect cofiring of coal and biomass Summary books on the market such as: - The Handbook of Biomass Combustion & Co-firing, Earthscan Publishing Improvements of large scale operation ongoing Cooperation with non-european countries in progress

46 Thank you for your attention