The Research Boiler at Agglomeration of the bed material in - PDF document

2010-11-16 The Research Boiler at Agglomeration of the bed material in Chalmers Univ. of Techn. fluidized bed reactors for thermal conversion of biomass - A threat for the development of the technology Lars-Erik Åmand and Britt-Marie Steenari Chalmers University of Technology Göteborg, Sweden Combustion/Gasification of Chalmers Gasification Process “Dirty” Biomass: Camera Chalmers • Forest residues 12 MW CFB boiler Heat, Electricity, Steam • Straw Flue Gas • Salix Gas • Residues from bio-ethanol plants? Hot Bed Material Combustible Gas Hot Bed Material Fuel • Residues from biodiesel plants Fuel, e.g. Biomass Waste, • Refuse derived waste (RDF) Coal or Sludge • Solid recovered fuel (SLF) Steam Air Steam Leads to: 1

2010-11-16 …and agglomerates in the Deposits on tube contains reactive panel in convection particle seal of the boiler alkali (K and Na) and section chlorides Leads to and corrosion…. Forest residues as fuel The Research Boiler at This presentation has the focus Chalmers Univ. of Techn. on agglomeration in fluidized beds for thermal conversion: 2

2010-11-16 Inlet to the cyclone from the top of Further into the cyclone the riser section Outlet from cyclone on the top on Inlet to cyclone the gas side 3

2010-11-16 Cyclone leg seen from above. Centre of cyclone seen from above Plugg of agglomerate of sand particles at the bottom. Cyclone leg seen from the inside Another picture from the inside of of the particle seel the particle seal after combustion of 100% of bark 4

2010-11-16 An agglomerate from the particle seal An agglomerate from the particle seal burning 100 % bark Scanning electron microscope (SEM) SEM on agglomerate Electron Gun of previous photos Acc. Voltage: 5-35 kV Condenser Lenses Resolution: 10-20 nm Image Objektive Lenses Objektive Lenses Scan Coils Aperture Detector Sample 5

2010-11-16 SEM-EDX on agglomerate. Spot Cross-section of agglomerate of Molten phase of potassium sodium analysis on surface of elements quartz sand particles calcium silicates (K-Na-Ca-Si-O) 2 1 3 4 5 No sludge ash components in molten phase (only traces) 6 Sludge 7 ash 9 8 particle Line scan of outer layer of bed Municipal sewage particle consisting of quartz sludge (MSS) and SEM-EDX of bed material wood+ straw pellets burning bark pellets only quartz sand coated with K+Ca+Mg+P Coarse sludge ash particles of Al+Si+K!+Fe+P 6

2010-11-16 Line scan of outer layer of bed particle consisting of quartz SEM image burning bark pellets only of particles taken from the bottom the bottom bed burning bark and Calcium in the outer layer. waste Potassium in the inner layer Line scan of outer layer of bed particle consisting of quartz SEM image burning bark pellets only of particles taken from the bottom the bottom bed burning bark and waste 7

2010-11-16 Line scan of outer layer of bed particle consisting of quartz SEM image burning bark, waste and sludge of bed particle consisting of quartz burning bark, waste and sludge Bottom bed sample Fuel: 23% straw on dry basis Wood and Straw Layers of K, Si ”Stone” of straw ash and Ca. Inner Dp=3 mm layer of K+Si, layer of K Si, Quartz bed outer layer rich material in Ca. Dp= 0.3 mm Char from 400 wood μ m pellets 8

2010-11-16 Conclusion: Acknowledgements Theory of agglomeration of the bed material in FBC • Main funding from the Swedish Energy administration Ash • Additional funding from VärmeForsk Additional funding from VärmeForsk A) Melt A) Melt B) Chemical between Reaction • Additional funding from the utility bed sand Glass melt Solid ash C) Ash + particles formation company Vattenfall Particles Ash Alkali + Reaction SiO 2 - sand Sticky Sticky D) Direct coating on coating on adhesion between bed particles quartz bed ash particles particles 9