Torrefied Biomass and its Handling Aspects – A State-of-the-art Review Victoria E. Hancock, Ioannis Dafnomilis, Dingena L. Schott, Gabriel Lodewijks Delft University of Technology Faculty of Mechanical, Maritime and Materials Engineering, Department of Maritime and Transport Technology, Section of Transport Engineering and Logistics 11.-14.07.2016 ICBMH’16, Darwin 1/16 Contents 1. Introduction and research objective 2. Biomass characteristics and Terminal Logistics 3. Handling aspects 4. Requirements and Design aspects 5. Conclusions 2/16 1. Introduction • increasing relevance of Renewable energy production in EU28 countries (2013) [1] biomass use for bioenergy production bioenergy 35.7 % other (+) renewable and abundant 64.3 % energy source (-) problematic transport, storage and handling of raw biomass • low bulk density, high moisture content • heterogeneous and fibrous consistency • bridging tendency [1] AEBIOM Statistical Report 2015 - European Bioenergy Outlook, Key Findings 3/16 1. Research objective • various pretreatments to improve properties of raw biomass • Torrefaction seen as promising thermal method Ø product with coal-like properties Ø used e.g. in the form of pellets or briquettes • What about transport, storage and handling? Ø research status on logistics and transport systems from port terminal to end user Ø biomass and coal infrastructure Ø handling characteristics of torrefied biomass 4/16 2. Biomass Wood Straw Agricultural wastes/ Peanut [2] cuttings Shrubs shells Virgin wood Crop wastes Treated wood [3] wastes untreated biomass • 7-60 % moisture content, 40-250 kg m-3 bulk density • low calorific values and energy density • fibrous, irregular shapes, low flowability [2] www.biomasspelletplant.com [3] www.biomass-energy.org 5/16 2. Biomass treatment methods • mechanical, chemical or thermal treatment Ø changing form and structure [4] v Densification uniform size and shape, 7-10 % moisture, up to 10 times higher bulk density v Torrefaction increased energy density, 1-5% moisture, brittle and hydrophobic nature [5] [4] Nielsen et al., 2009 [5] www.cfnielsen.com 6/16 2. Biomass Logistics • specific demands for biomass handling, transportation and storage Ø prevention of degradation and extensive dust generation Ø avoidance of moisture uptake [6] • material properties influence choice of handling equipment • biomass supply chain: v transhipment v transportation and transfer v storage v reclaiming 7/16 [6] www.guttridge.com 2. Biomass Logistics • Solid bulk transhipment Ø Grabs, Pneumatic systems, Self unloaders [7] • Transportation and transfer Ø Belt conveyors, Pouch conveyors, Pipe conveyors, Bucket elevators, Screw conveyors, Transfer station [8] • Storage Ø Silos, Bunkers, Bins, Flat storage, Dome storage [9] 8/16 [7] www.balticservice.eu [8] www.vertechbiomass.com [9] http://chinafpm.en.made-in-china.com 2. Biomass Logistics • Reclaiming systems Ø Push floor, Keith walking floor, Sliding frame, Hydraulic rotor discharger, Screw reclaimer, Tubefeeder, [10] Underpile chain reclaimer, Kamengo feeder, Feedex reclaimer, Hopper • Loading systems & inland transportation Ø Truck and Rail loading station, Drax rail wagon, Floating crane, Choke spout, Boom feeder Ø Trucks, Train, Ships/Vessel/Barge [11] 9/16 [10] www.andritz.com [11] www.youtube.com (Cleveland Cascades Ship Loader) 3. Handling aspects of torrefied biomass • Modification of biomass through torrefaction Ø more homogenous solid product, low moisture content Ø increased heating value and grindability Ø shows hydrophobic nature Ø low bulk density (180-300 kg m-3) can be greatly increased by compressing the torrefied biomass Ø same durability as regular wood pellets Ø angle of repose similar to hard coal [12] Material Moisture Bulk Calorific Angle of Content (%) Density (kg m-3) Value (MJ kg-1) Repose (°) Wood pellets 7-10 650-750 15-16 34-40 Torrefied 1-5 750-850 20-24 38-44 Pellets 10-15 800-850 23-35 27-45 Hard coal 10/16 [12] Tumuluru et al., 2011; Wu, 2012; Chen et al., 2015; Sinnott & Towler, 2013 3. Handling aspects - material properties • handling of bulk solids influenced by: v physical material properties v handling equipment in contact with material v interaction of bulk solid material and handling equipment • Interacting material properties Ø mechanical durability: moisture content, particle size distribution Ø particle density: particle size, moisture content Ø angle of repose and particle size distribution, moisture flow properties: content 11/16 4. Coal infrastructure • general elements shared by both bulk and biomass supply chain • operations at a coal handling Dry Bulk Import Terminal: Transshipment Transfer Transport Transfer Storage Sea-going vessel Unloading direct Storing Coal Stock pile (open) direct Transport Transfer operations points Silo (closed) Distributing Reclaiming modality Loading (Ship/Train/Truck) 12/16 4. Equipment Design Aspects • design of bulk material handling equipment is influenced by many factors Ø type of handled commodity Handling Types of Equipment/ Relevant Material Properties Functions Handling Facility Transshipment Ship unloader, ship loader Particle Size, Bulk Density Open & Closed Conveyors: Particle Size, Bulk Density, Angle of Transport Belt Conveyor, Screw Repose, Wall Friction Angle, Internal Conveyor, Pipe conveyor Friction Transfer chutes, Feeders: Belt Transfer Wall Friction Angle, Internal Friction Feeder, Apron Feeder Silos, Hoppers Particle size; Bulk Density; Flow Properties: Effective Angle of Internal Storage Friction, Internal Friction, Unconfined Yield Strength, Wall Friction Angle Open-area Stockyards Angle of Repose 13/16 4. Equipment Design Aspects • conveyor Ø belt speed [13] Q = qvρb = 3.6Avkρb • transfer chute • silo Ø velocity, cut off angle Ø bulk density, unconfined yield strength Ψ ​d↓crit =H(​Θ↓c )​​σ↓c,crit /g​ρ↓b,crit [15] [14] 14/16 [12] Tumuluru et al., 2011; Wu, 2012; Chen et al., 2015; Sinnott & Towler, 2013 5. Conclusions • research concentrates mainly on torrefaction process • fewer studies on handling characteristics of torrefied products in the supply chain Ø physical and chemical material properties Ø lack of studies regarding the mechanical behaviour • extensive research of torrefied biomass under varying transport and storage conditions • further research on aspects such as dust generation, self- heating, off-gassing 15/16 Thank you for your attention! Victoria E. Hancock, Ioannis Dafnomilis, Dingena L. Schott, Gabriel Lodewijks Faculty of Mechanical, Maritime and Materials Engineering, Department of Maritime and Transport Technology, Section of Transport Engineering and Logistics, Delft University of Technology Mekelweg 2, 2628 CD, Delft, the Netherlands 16/16 .