1. Pellet Stove Design Challenge 2016 Stove: PEWOS (Team Wittus) Niels Wittus 1, René Bindig 2,3, Jan Kossack 2, Ingo Hartmann 2,3, Frank Werner 3,4, Torsten Schröder 5, Christian Thiel 2, Saad Butt 2 1) Wittus – Fire by Design 2) DBFZ 3) ETE EmTechEngineering GmbH 4) Specht Modulare Ofensysteme GmbH & Co KG (xeoos) 5) SL Systemlösung Haustechnik GmbH

2. Wittus – Fire by Design Mission To select and import a broad range of quality premier European designed hearth products (fireplaces, stoves, and accessories) to meet the needs of the American contemporary marketplace

3. History and Focus Wittus - Fire by Design has over 35 years of successful sales and marketing efforts specializing in the high-end residential, builder, architect, and designer markets The only company that focuses exclusively on the contemporary European marketplace Product selection is based on: –Artistry and award winning design – differentiation (not cost) –Technology – utilizing quality, sophisticated state of the art systems –Environment – clean burning, highly efficient, sustainable heating, and ease of use

4. Wittus Team – Contribution and Objective Wittus - Fire by Design® and Specht XEOOS® are looking to provide the design aspect of the team. Hopefully this will provide the “packaging” for successful sales and marketing efforts DBFZ, ETE EmTechEngineering, and SL Systemlösung Haustechnik are focusing on bringing a new level of clean burning technology through heat transfer and catalysis. This sophisticated state of the art technique provides the “guts” for next generation products Our objective is to offer future pellet burning products that are clean burning, highly efficient, with sustainable heating and ease of use

5. Challenges – General remarks 5 Emission abatement at wood combustion: “Ultra low emission combustion” Flue gases: Particulate Matter and Organic Compounds Primary measures: Best available technics for pellet combustion Integrated secondary measures: Heat transfer and catalysts

6. Challenges – Biomass Combustion 6 Wood log for heat production non-stationary process strong influence of the user on the emissions Fuel properties (e.g. H 2 O content) crucial for emissions from incomplete combustion Higher PM emission: mainly Soot particles Requirements for emission abatement Reducing the user influence with electronic control systems Standardized wood pellets with low mineral content Two stages for combustion: 1) wood gasification and 2) Total oxidation Catalytic emission control Heat transfer optimizationCombining wood log and wood pellet unit Wood pellets for heat production stationary process minor influence of the user on the overall system Inorganic ingredients (e.g. Potassium) determining particulate matter emissions Lower PM emission: mainly Metal oxides

7. Background: Micro-scale biomass combustion Small-scale combustion systems in Europe 1 Heating appliances in the capacity range 0-15 kW on the European market are basically fireplaces and stoves (26 Mio wood log stoves in EU 27)  batch operation, upper flame combustion, user influence  high emissions of CO, OGC and PM Pellet boilers and stoves: ≥ 10 kW Wood log gasification boiler (downdraught): ≥ 15 kW Better energy performance of buildings Decrease of heat demand (<< 10 kW, for low-energy houses < 5 kW) Currently available systems achieve small annual utilization ratios, frequently operation at partial load with low efficiency and high emissions Development of continuous biomass combustion systems < 5 kW 1 Mudgal S. et al., LOT 15 Solid fuel small combustion installations – Economic and market analysis, Bio Intelligent Service S.A.S, France, 2009 7

8. Development of a micro-scale installation 8 For the development of micro-combustion systems 3 research topics were identified: fuel preparation and feeding (automatic and continuous fuel supply) Furnace construction (down draft, grate design) control systems (air supply, combustion control)

9. Development of a micro-scale installation 9 Comm inuted wood Temperature profile in the oxidation reactor High temperature stable catalyst (Alumina foam)

10. Emission reduction by catalysis 10 Application of ceramic foam in micro-scale installation Mixed metal oxides on alumina foam ◦Cell density: 10 ppi ◦Reduction of CO and VOC up to 70 % possible (tested in downdraught stove) Integration into the combustion chamber No blockage after 25 h of operation Heat accumulation ◦Temperature increase of 100-150 K in flame zone (Flue gas temperature zone: 700-800 °C) Aim of Investigations: Characterization and analysis of materials and occuring processes during catalytic gas treatment in biomass combustion systems

11. Emission reduction by catalysis 11 Possible emission reduction by integration of catalytic active foams University Leipzig, DBFZ and Specht GmbH: Developement of catalyst for biomass combustion systems ◦Mixed metal oxides on alumina foam Effect and long-term stability for application in downdraught stove Comprehensive characterization for transfer to other installations ◦Occuring catalytic reactions and catalyst properties (range of application)  Patent application has been approved (2012)

12. Starting point for the development 12 xeoos „TwinFire“ wood log stove from German company Specht: Patent: Stove for solid fuels (EP 1340943 A2) Stahl- und Apparatebau Specht OHG (2002)

13. Emission data with Alumina foam 13 System Low emission combustion PM < 5 mg/m³ CO < 5 mg/m³ Lambda: 1.1 – 2.2 Reproducible operation with automatic feeding of comminuted wood Development towards practical system is going on System is used for catalyst screening Activity Ageing Abatement Soot Transcription/scale-up to a pellet burner unit was carried out  PEWOS stove

14. Two-stage combustion 14 Separation of: 1. Pyrolytic wood decomposition 2. Oxidation of burnable gases Integration of: 1. Heat transfer unit 2. Catalytic emission control Stage 1 Stage 2 Pellets feeding Primary air Secondary air Catalysts

15. Emission Values 15 Values in normal conditions and mg/m³ (13 % O 2 ), 180 minutes mean value CO = 20 mg/m³ (0,7 g/h) PM < 10 mg/m³ (0,35 g/h) O 2 = 10 Vol.-% Efficiency = 80 %, Heat Output = 45 000 Btu/h (13 kW)

16. DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH Torgauer Straße 116 D-04347 Leipzig Tel.: +49 (0)341 2434 – 112 E-Mail: info@dbfz.de www.dbfz.de Working Group Small scale furnace systems, Department Thermo-chemical Conversion „Small scale furnaces and catalytic emission reduction“ Contact René Bindig Tel. +49 (0)341 2434 – 498 E-Mail: rene.bindig@dbfz.de E-Mail: rene.bindig@ete-ing.de www.ete-ing.com