Presentation on theme: "Biochar Properties & Production Techniques"— Presentation transcript:
1 Biochar Properties & Production Techniques Zoe Wallage Low Carbon Innovation Centre University of East Anglia
2 Presentation Outline Introduction & Overview Biochar Production TechniquesBiochar Properties & UsesUEA Case StudySummary of FindingsUEA’s Biomass Gasification CHP Plant
3 Research Overview Atmospheric Carbon (CO2) Terrestrial Carbon (SOC) Aim:Review the potential for carbon sequestration via biochar & assess the impact this technology may have on regional productivity & sustainabilityObjectives:Evaluate the technologies available for biochar productionIdentify the parameters influential to biochar yield & qualityAtmospheric Carbon (CO2)Terrestrial Carbon (SOC)
4 What is Biochar & Why is it Important? Introduction slide
5 Biochar Carbon CycleLehmann (2007) Nature 447:Lehmann et al (2006) Mitigation & Adaptation Strategies for Global Change 11:
6 Thermal Conversion of Biomass Introduction slideLehmann (2007) Frontiers in Ecology & the Environment 5:
7 Thermal Conversion of Biomass Overall an endothermic process:Energy is required to initiate the processAt present the technologies can be split into two distinct categories:Charcoal productionBio oil or syn gas productionHowever, there is potential to move towards a third:“Tri-generation” that makes use of the biochar, energy-rich co-products (bio oil, syn gas) & heatBio OilBiocharSyn GasHeat withoutAirBiomass
8 Biochar Production Techniques CHP GasificationSlow Pyrolysis (retort)Slow pyrolysis (kiln)Temp & DurationSolid(Biochar)Liquid (Bio oil)Gas (Syn Gas)Slow Pyrolysis~500CDays35%30%Fast PyrolysisSeconds12%75%13%Gasification>800CHours10%5%85%Thermal conversion of biomass is the temperature driven chemical decomposition with limited oxygen, and is sometimes referred to as pyrolysis. However, just as biomass can be drawn from a number of sources, biochar and its co-products can be produced through a number of thermochemical processes, including slow (carbonisation), intermediate, and fast pyrolysis, and gasification (Demirbas 2004c; Winsley 2007). All of these processes produce some form of char (Gaunt & Lehmann 2008). Thermal technologies can effectively process all forms of biomass, and whilst combustion and gasification of biomass have been commercially proven, pyrolysis is often thought to offer greater flexibility as it can generate varying yields of solid (char), and liquid and gaseous (energy) outputs (Warnken 2008).Fast Pyrolysis
9 BEST Energies: Biochar via Slow Pyrolysis Biochar ProductionDynomotive:Bio oil viaFast PyrolysisEprida: Hydrogen & Char Fertiliser via PyrolysisUniversity of Hawaii:Flash Carboniser (Fast Pyrolysis)BEST Energies: Biochar via Slow Pyrolysis
10 Biochar Properties High carbon content (60 – 95% C) Resistant to biodegradationSignificant adsorptive qualities (similar to activated carbon)Nutrients (& contaminants) essentially lock on to the structureIncreases moisture holding capacityEnhances microbial biomass
12 Biochar Properties: Process Conditions TemperatureAs temperature increases:Biochar yield decreasesFixed carbon increasesSurface area increasesAsh content increasesStructural Development
13 Biochar Properties: Feedstock Materials The variable nature of the chemical constituents in the feedstock biomass influence the structure, properties & yield of biochar.RoundwoodAs may be expected, the variable nature of the chemical constituents in the feedstock biomass influences the structure, properties and yields of the resulting biochar and energy-rich co-products. For example, materials with high lignin concentrations have been found to generate higher biochar yields (Demirbas 2004c), whilst Nik-Azar et al (1997) demonstrated that the mineral content is also influential, with woody material impregnated with Na, K and Ca found to yield up to 15% more biochar than the original beech wood. In contrast, extractive compounds have been found to influence the gaseous emission profiles formed during pyrolysis, although they are not thought to substantially influence charcoal yield due to their low concentrations (Brown 2009).WoodchipRice Husks
18 UEA Case Study 1.4 MWe 2.0 MWth 6, 719 t CO2 yr-1 (34%↓) 3% Biochar Yield300 t char yr-1195 t C yr-1716 t CO2 yr-1 (4% ↓)Biochar...& this particular systemis optimised for energy production!
19 Summary of FindingsBiochar is produced by the thermal decomposition of biomass using:Slow PyrolysisFast PyrolysisGasificationTechnology must be “closed-loop” with efficient product recoveryBiochar yield & quality varies significantly with feedstock type & process conditionsBiomass gasification CHP is currently viable & will produce modest quantities in the near-termBio OilBiocharSyn GasHeat withoutAirBiomass
20 So, the future is in our hands… Blue text slide with white bullet pointsThank you!