Challenges and opportunities? Kari Pieniniemi Phil.Lic. (Chem) Centria Univeristy of Applied Sciences Ylivieska

Transcription

1 Small scale l biomass gasification Challenges and opportunities? Kari Pieniniemi Phil.Lic. (Chem) Centria Univeristy of Applied Sciences Ylivieska

2 Content of presentation Climate Change is a Global Challenge Renewable Energy is the answer Biomass gasification Small scale biomass gasification Gasification Strengths and Weaknesses Technical barriers Centria Pilot R&D Gasifier 2

3 Climate Changeis a Global Challenge CO 2 is the primary greenhouse gas Human activities, such as the burning of fossil fuels release large amounts of carbon to the atmosphere Renewable energy (RES) is the answer " " targets, set three key objectives for 2020: A 20% reduction in EU greenhouse gas emissions from 1990 levels; Raising the share of EU energy consumption produced from renewable resources to 20%; A 20% improvement in the EU's energy efficiency. On 27 March 2013, the European Commission adopted a Green Paper on "A 2030 framework for climate and energy policies". IPCC IPCC Fourth Assessment Report. Working Group I Report The Physical Science Basis. Summary for Policy Makers, s. 3. Energy Roadmap 2050 to low carbon economy in 2050 RES in energy consumption 75 % in 2050 RES in electricity consumption reaching 97 % higher energy efficiency and shares of renewables are necessary to meet the CO 2 targets in 2050 Energy roadmap 2050 (COM(2011) 885 final of 15 December 2011) 3

4 Renewable Energy is the answer Renewables Bioenergy GAS; 21% OIL; 35% Renewables; 13 % 77 % 50 EJ 87 % 43 EJ Nuclear; 6% COAL; 25% World Primary Energy mixture 100 % = 500 EJ (eksajoule = J) 15% 8% Other renewables Hydropower Bioenergy 9% 4% Municipal & Industrial Waste Agricultural Crops & By products Wood Biomass 4

5 Renewable Energy is the answer But there are Challenges. For the R&D community R&D to reduce energy unit costs Realistic perception of resource availability Sustainable production and closed carbon cycle Overall 20% Renewables means 2/3 Bioenergy Finally.. The stone age did not end for the lack of stones and the oil age will end long before the world runs out of oil For policy makes Recognize cost gap between renewable and fossil fuels resulting market failure requires policy measures Message to consumers higher cost cannot be compensated by public subsidies In a level playing field industry will take over Sheiikh Zaki Yamani former Saudi Arabia Oil minister Kokkola Material Weeks 5

6 Renewable Energy is the answer BIOENERGY AND BIOFUELS are an opportunity for the Finnish Forest Industry* 1G First Generation HIGHBIO2 2G Second Generation * Hans Sohlström, Vice President UPM Kymmene Corporation, Finland presentation in 18 th European Biomass Conference Lyon France Kokkola Material Weeks 6

7 Biomass utilization technologies Technology/Process State of the Art Main Challenges Combustion Commercial available, low efficiency Feedstock variability, feedstock at small scale contamination, combustion stability Demonstration scale, Early Gasification Cost reduction, gas quality commercialisation ili stage Anaerobic digestion Processes to biodiesel Fermentation to bioethanol Commercial status but high costs, low efficiency and low yield Proven technology, high cost and low yield Commercial status, high cost, low yield Scale up, cost reduction and use of mixed wastes Cost reduction and continuous production Cost reduction, higher yield 7

8 Biomass gasification Biomass gasification is a promising, energyefficient technology for renewable energy generation Gasification: Thermal conversion of biomass into a low calorific to medium calorific value combustible gas Producer gas: The mixture of gases produced by the gasification of biomass at relatively low temperatures (700 to 1000 C) can be burned in a boiler for heat production, or in an internal combustion (IC) gas engine for combined heat and electricity (CHP) Synthesis gas (Syngas): Mainly carbon monoxide (CO) and hydrogen (H 2 ) Can be transferred to synthetic natural gas (SNG) or synthetic diesel (Fischer Tropsch synthesis) or use as a feedstock in production ofgreen chemicals Gasification in higher temperatures Cleaning of the producer gas 8

9 Biomass gasification Gasification is one stage in the thermal biomass conversion process* Gasification stage gas composition: Carbon monoxide (CO), hydrogen (H 2 ), methane (CH 4 ) light hydrocarbons, water vapour (H 2 O), carbon dioxide (CO 2 ), nitrogen (N 2 ), tar vapor, and ash particles *H.A.M. Knoef (Ed,.) (2005) Handbook Biomass Gasification,. ISBN , p. 13 Tar content 100 g/nm 3 in an updraft gasifier, 10 g/nm 3 in a fluidized bed gasifier and 1g/Nm 3 in a downdraft gasifier. (Neeft, 1999) 9

10 Small scale biomass gasification Product gas or synthesis gas can be used in Small scale CHP (combined heat and power) units for heat and electricity production Production of biofuels and chemicals Downdraft gasification is ideal for small scale CHP production up to about 1 MW th Small scale* CHP electrical power < 100 kw Micro scale CHP electric capacity < 15 kwe There are about 50 commercial gasification plant manufacturers in Europe, USA and in Canada from which 75% were fixed bed downdraft type, 20% fluidized bed systems, 2.5% fixed bed updraft type, and 2.5% were of various other designs *Dong L., Liu H. and Riffat S Development of small scale and micro scale biomass fuelled CHP systems A literature review. 2009, pp

11 Small scale biomass gasification Markets for small scale CHP 1. Biomass CHP Power Plants Small scale CHP has growing markets in Europe and other OECD countries 2. Carbon free Gas for Industry Energy intensive i industries i (metals, cement etc.) )has a strong needs to diversify fuel consumption and reduce energy costs & CO 2 emissions (Climate Change) 3. Decentralized Power Remote areas are affected by high increasing prices of fossil fuel for power production based on diesel generators 11

12 Small scale biomass gasification 12

13 A Success Story* Small Scale Scale BiomassGasification, XYLOWATT XYLOWATT ( Biomass gasification CHP manufacturer and turnkey provider from Belgium Bli aims to be a strong international actor in the smallscale Woodgas CHP (0,1 10 MWe) LHV 5,4 MJ/Nm 3 High quality syngas (< 10 mg/nm 3 tar, < 10 C, water free) Fully automated plant High efficiency with syngas use in IC engine (75% total efficiency, 25% net electrical efficiency) Flexibility for the operation (100% woodgas or 100% NG) Fully automatic, instantaneous power regulation, totally remote controlled MWh/yr of electricity MWh/yr of heat Saves 1644 CO 2 Tons/yr Uses 600 odt/yr of wood *Handbook Biomass Gasification (2012) H.A.M. Knoef (Ed,.), Chapter 2 Success stories on biomass gasification p 20. ISBN

14 A Success Story Kempele Ecovillage since 2009, Volter Oy The electricity and heat for the ten houses in Kempele Ecovillage are produced by a CHP plant in the village using Vlt Volter'swood gasification technology One liter of oil can be replace by 2 kg of dry wood Wood gas is fed to IC engine connected to generator to produce electricity 14

15 Gasification Strengths and Weaknesses Gasification and direct combustion have a number of general strengths and weaknesses Strengths Weaknesses Gasification Direct Combustion Lower NOx, CO, and particulate emissions Potential for more efficient conversion process when generating power Virtual elimination of water needs if generating power without a steam turbine Proven, simple, lower cost technology Equipment is widely available, complete with warranties Fuel flexibility in moisture and size People comfortable with technology Technology is in the development and demonstration phase Need fuel with rather low size distribution and moisture it content t Greater NOx, CO, and particulate emissions Inefficient conversion process when generating power alone some advanced designs are improving efficiency Requires water if generating power with a steam turbine 15

16 Gasification Strengths and Weaknesses Potential Health, Safety and Environmental aspects of gasification plants* Health, safety and environmental (HSE) issues are found an important barrier to the market uptake of biomass gasification technology Risk assessment in biomass gasification is becoming increasingly important all over the world Guideline for Safe and Eco friendly Biomass Gasification guide.eu/ *H.A.M. Knoef (Ed.) Handbook Biomass Gasification 2nd Ed. (2012). ISBN , p

17 Gasification Strengths and Weaknesses Producer gas properties regarding to HSE aspects Small scale biomass gasifiers operate normally with air as a gasification agent => gas composition differs largely yfrom other gases like biogas or natural gas desired products: permanent gas (H 2, CO, CH 4, CO 2, N 2 ) and ashes with low remaining carbon content undesired products: particulate matter, dust, soot, inorganic (alkali metals), H 2S, COS, NH 3, HCN, HCl and organic pollutants (tars or PAH compounds) Typical characteristics of producer gas compared to other gases Parameter Producer gas Biogas Natural gas CO (vol %) <1 <0.5 H 2 (vol %) <1 <0.5 CH 4 (vol%) CO 2 (vol %) <1 N 2 (vol%) <1 <1 Heating value MJ/Nm Explosion range (vol%) Air to gas ratio

18 Gasification Strengths and Weaknesses Explosion levels and combustion pressure The following analysis comes from a two stage gasification plant. The first stage is evaporation and pyrolysis of wood chips by indirect heating. The second stage is pyrolysis of gases by direct heating with combustion products. Gas composition 1st stage 2nd stage Tar components 0.04 mole/mole 0.02 mole/mole Mole weight 24.3 kg/kmol 22.3 kg/kmol Stoichiometric combustion air 3.00 mole air/ mole 1.59 mole air/ mole gas mole air/ mole gas gas LEL UEL Deflagration pressure at 15 C 6.6 barg 6.1 barg Flametemperature at 15 C 1695 C 1575 C Deflagration pressure at 500 C 3.4 barg 2.5 barg Flame temperature at 500 C 2480 C 1820 C 18

19 Gasification Strengths and Weaknesses Guideline for Safe and Eco friendly Biomass Gasification RiskAnalyzer computer program The Guideline is intended to be a training tool and a resource for workers and employers to safely design, fabricate, construct, operate and maintain small scale biomass gasification facilities (up to about 1 MWe) guide.eu/ 19

20 Gasification Tehnical Barriers Tars in producer gas is the largest single problem that has to be overcome in order to commercialize gasification processes In Energy Production Most important way to avoiding condensation is to maintain the gas above the tar dew point (~ 400 C) Internal combustion (IC) engines and synthesis applications require cooling of the gas before use In Large Scale: Two of the most important operational barriers for both the BFBG and CFBG are the risk for defluidisation and the presence of tar in the product gas. In Production of fuels and chemicals from the syngas As soon as the temperature of the producer gas drops below the dew point, tars will form aerosols or requirements on product gas purification are very directly condense on the inner high to prevent poisoning of the catalysts. surfaces of the equipment, resulting li in plugging and fouling of pipes, tubes, and other components downstream the gasifier. Ref: Stefan Heyne, Truls Liliedahl, Magnus Marklund,(2013) Biomass gasification a synthesis of technical barriers and current research issues for deployment Kokkola at Material large scale Weeks (f3 2013:5) 20

21 Tar cleaning Gasification Technical Barriers Tar free producer gas can be achieved in many ways. Physical methods used for removing condensed tar aerosols are same used in removing particles; wet scrubbers, electrostatic precipitators, etc. Thermal and catalytic methods 21

22 Tar cleaning Gasification Technical Barriers The occurrence of tars in producer gas is still the single largest problem that has to be overcome before commercialize gasification processes for various purposes There are two main strategies for dealing with the tar once it is present in the producer gas: removal and use and in situ conversion Removal and use, OLGA process OLGA: Oil Scrubber OLGA has been developed d by the Energy Research hcentre of the Netherlands (ECN) The washing and absorption media ( oil ) is fatty acid methyl esters (FAME) produced by the transesterification of triglycerides from plants (bio diesel) OLGA operates in the temperature range where tars condense, but water doesn t (above the dew point of water) 22

23 Tar cleaning Gasification Technical Barriers Removal and use,olgaprocess Condensation step: Inlet temperature of the gas can be up to 350 C Gas is cooled down by the recirculating oil, which washes out the condensed heavy tars Part of the oil/tar mixture is returned to the gasifier WESP is used to remove droplets of tars and oil from the gas Light tar absorber: Absorber temperature is just above the water dew point Stripper: Absorbed b tars and oil are fed into a stripper where the light tars are stripped off by hot air Regenerated oil (FAME)is fed back to the absorber 23

24 Tar cleaning Gasification Technical Barriers In situ conversion Catalytic ti steam reforming tars are converted in the producer gas by some kind of thermal or catalytic process catalyst of metallic nickel (Ni) water is consumed during the reaction Catalytic tar cracking Basic catalysts, such as dolomite, magnesite, and olivine, must be calcinated into oxides (activation) high temperature (>700 C) and low pressure (<10 bars) tar cracking catalysts convert tars into synthesis gas (i.e., CO, CO 2, and H 2 ) but not into the lower hydrocarbons reforming temperatures of ~850 C and steam/carbon ratios 3 nickel based catalyst is very sensitive to contaminants, especially sulphur 24

25 Gasification Technical Barriers Producer gas contains dust, ash, tars, and other contaminants and needs to be cleaned before use. Tar, dust and ash removal Cyclones Cyclones are standard equipment in producer gas treatment. t t Cyclones generally remove particles from 1 mm down to 5 m in size and work with dry particulates Candle filters Candle filters consist of a porous metallic or ceramic filter material that allows gases to pass but not the particulates Candle filters can be operated at temperatures up to 500 C and can effectively remove particles in the mm range Bag filters Cyclones can operate at actual gas temperatures (up to C) to avoid cooling the gas Cyclones can be used in series as multi cyclone Bag filters are made of polymeric, ceramic, or natural fibres They operate like candle filter and are regularly vibrated or back flushed to remove the built up filter cake. The maximum operation temperature of a bag filter is approximately 350 C 25

26 Gasification Technical Barriers Tar, dust and ash removal Small- scale biomass CHP In a small scale biomass gasification power plant for IC Electrostatic precipitator p (ESP) ) engine tar and ash particles are filtered fromthe gas In an electrostatic precipitator, ash and dust particles receive a negative electric charge when they pass an electrode connected to a high voltage source ( kv DC). Electrostatic precipitators can be operated at temperatures up to approximately 400 C. Collected dust must regularly be removed by vibration Wet electrostatic precipitators (WESP) WESP are also used to remove oil droplets (FAME) released by oil scrubbers used for tar removal stream using o Cyclone to remove coarse particles o Scrubber for removal of tar, some dust particles and gas cooling o Catalytic tar cracking units o Course filters made of packed beds of porous materials o Fine filters made from fabric material for removal of very fine particles Typically producer gas is cooled to about 35 C o increases density => increase in the engine power output o lowers thermal efficiency i o increases need for waste water treatment (harmful e.g. phenols ) 26

27 Centria Pilot R&D Gasifier

28 Centria Pilot R&D Gasifier CENTRIA Gasifier is based on patented EK gasifier (GasEK) o Downdraft gasifier o IC engine CHP o Stirling engine CHP Used in HighBio2 research project Low tar content Power Tar concentration of the product gas (dry, STP: 0 C, 1 atm) 9 kw e 24 ± 5 mg/nm 3 Fuels used in the gasification Solid, air dried wood chips is normally used as a fuel in the gasification process size of the chips 0 to 100 mm and moisture content can be up to 40 vol % Kokkola Material Weeks 28

29 Centria Pilot R&D Gasifier 1. Wood chip storage 2. Wood chip screw conveyor 3. Gasifier 4. Raw gas pipe 5. Scrubbers 6. Water tank 7. Ahb Ash barrel 8. Engine 8.4 liter 9. Generator 50 kw 10. Startup pipe 11. Eh Exhaust pipe 12. Heat exchanger for exhaust gas 13. Cooler 14. Heat exchanger Centria Pilot Gasifier is a Small Scale CHP based on wood gasification Kokkola Material Weeks 29

30 Stirling engine CHP Centria Pilot R&D Gasifier Gas engine CHP Downdraft gasifier and 8 cylinder 5,4 L gas engine Electric power 20 kw e Thermal power 50 kw th Solo Stirling engine electric power 9 kw e. thermal power 26 kw th From left Yrjö Muilu and students Kauko Jarva and Mauri Niskanen Kokkola Material Weeks 30

31 Centria Pilot R&D Gasifier Emissions of the IC engine* Measured flue gas component Measured flue gas composition Concentration (dry, STP 0 C, 1 atm) mg/nm 3 O 2 04vol% 0.4 CO 2 17 vol% CO 568 ppm 170 SO 2 8 ppm 25 NOx 162 ppm 332 Emissions of the Stigling engine** Measured flue gas component Measured flue gas composition Concentration (dry, 6% O 2, STP 0 C, 1 atm) mg/nm 3 O 410vol% 4,10 O 2 CO 2 16,6 vol% CO 9 ppm 10 SO ,2 ppm 04 0,4 NOx 22,5 ppm 41 *Muilu Y., Pieniniemi K., Granö U. P.& Lassi U (2010) A Novel Approach to Biomass Gasification in a Downdraft Gasifier. In: Proceedings of the 18th European Biomass Conference and Exhibition, 2010 in Lyon, ISBN 10: , ISBN 13: pp **Pieniniemi K., Muilu Y. and Ulla Lassi (2013) Micro CHP Based on Biomass Gasification in a Downdraft Gasifier and Stirling Engine. In: Proceedings of the 21st European Biomass Conference and Exhibition, 2013 in Copenhagen, ISBN: , DOI /21stEUBCE2013 2CV pp

32 Main task of the CENTRIA R&D in HIGHBIO2 research project is to support the local, decentralized small scale heat and power production by research and development work in co operation with the partner universities Focus of the research in CENTRIA R&D is o on improving controllability of the gasification process and o on online analysis of the produced syngas and flue gases Partners and Funding: 32

33 Conclusion - Future for Small-Scale Biomass Cogeneration Wood biomass remains the main energy source for widespread biomass powered CHP systems at small and micro scale Gasification of biomass using a gas engine (or gas turbine) presents interest possibility for small to medium scale co-generation The Stirling Engine coupled with a gasifier is an interesting option for distributed CHP and should be available very soon Tars are still the single largest problem that has to be overcome before commercialize gasification processes 33

34 Video Latest development in Biomass Gasification VTT Biomass and Waste Gasification, from R&D to industrial success ( ) (YouTube) VTT Gasification of Waste technologies ( ) (YouTube) 34