novel method for the determination of unknown biomass fuel...
TRANSCRIPT
Novel method for the determination of unknown biomass fuel properties based on results of an online monitoring in a 300 kW CFB pilot plant Daniel Bernhardt, Michael Beckmann
8th International Freiberg Conference, 12-16 June 2016, Cologne, Germany
Faculty of Mechanical Science and Engineering,
Institute of Process Engineering and Environmental Technology, Chair for Energy Process Engineering
Slide 1
Motivation – Increasing Fuel Flexibility in biomass energy use
Fuel range
- Small amounts (<10.000 t/a) - Different sources Variable fuel properties
Varying Flue gas emissions
Deposits/Corrosion vs. Availability/Costs
Source: Frandsen, 2011
Challenges
Flexible Biomass utilization needs biomass specific process optimization
Power Plants
- Design and operation is optimized on „regular fuel“
Source: BEB Bioenergie Baden
Slide 2
Model-based process control
New targets for control variables
Fuel (C,H,O,N,S)
?
Fuel, Air, Additives
Control Variables
Identification of unknown fuel properties
Power Plant (e. g. CFBC)
Source: BEB Bioenergie Baden
Process data acquisition
Monitoring (Sensors + Models)
Process analysis (Online-Balancing)
Prediction & Optimization
0 10 20 30 40 50 60
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
Massenverteilung des Rezimaterials
Cellulose [wt.-% daf] Cellulose [wt.-% daf]
Slide 3
Characterization of the feedstock material – Organic composition of natural biomass
Hem
icel
lulo
se [w
t.-%
daf
]
Lign
in [w
t.-%
daf
]
Extr
activ
es [w
t.-%
daf
] - Cellulose, Hemicellulose & Lignin are main components (Σ = 92 wt.-% daf) - Distribution varies in wide range - No similarities within biomass groups - Linear correlation between Hemicellulose & Cellulose
Cellulose [wt.-% daf]
Energy-Balance
Slide 6
Identification of Unknown Fuel Properties – Online - Balancing
Elemental-Mass-Balances Assumptions: ξFuel,N = ξFuel,S = 0
ξC, ξH, ξO, ξH2O
& hu
Additional Statistic
ξC, ξH, ξO, ξH2O
Slide 8
Identification of Unknown Fuel Properties – Structural Analysis
Elemental composition and heating value of structural components
i…C, H, O, N, S j…Structural component
Slide 9
Identification of Unknown Fuel Properties – Structural Analysis - Mathematics
Objective function
Constraints
Summary
- Presented method provides “Online” information about unknown fuel properties of biomasses:
- Online Balancing: ξC, ξH, ξO, ξH2O and hu
- Structural analysis: ξCel, ξHCel, ξLig, ξExtr and ξN, ξS
- Validation was realized for three biomasses with different compositions
- Method exemplarily developed for CFB combustion of biomass is transferable to other firing systems (e. g. grate systems)
- Deeper information about extractive composition would improve the accuracy of the method
Slide 12
Further work – novel process model for CFB combustion of biomass
Slide 13
Process data -fuel (structural composition!) - reaction gas - temperature and pressure
Forecast: - burn out - emissions and Process optimization - air distribution - air preheating - additives
Simplified process model based on structural composition