modeling of a solar-thermal reactor for synthesis gas production
TRANSCRIPT
Elizabeth Saade1, David E. Clough1, Carl Bingham2, Alan W. Weimer1
1 Department of Chemical and Biological Engineering University of Colorado at Boulder
2 National Renewable Energy Laboratory, Golden, CO
Modeling of a Solar-Thermal
Reactor for Synthesis Gas Production
May 15th, 2012
A control system will improve the operation of a solar-thermal reactor
H2 + CO + CO2
Steam Biomass
Operation of solar-thermal reactor is dependent on available sun
As the clouds cover the sun, the reactor will be cooled within 1 or 2 minutes
If the clouds are partially covering the sun the reactor can still operate
How is the control system going to work?
PT
TT
FIC
FT
RC FIC
FT
Solar irradiation
MPC
Steam Carbon
H2 + CO + CO2
HT Solar
irradiation predictor
AT
Attenuator
Dynamic model of the reactor
DOMAIN:
H2 + CO + CO2
Carbon + Ar
Steam Reflective cavity
Single tube
35 c
m
9.8
cm
20 mm I.D.
Dynamic model of the reactor
STRATEGY:
≈
CARBON STEAM CARBON STEAM
H2 + CO + CO2
H2 + CO + CO2
CARBON STEAM
T1
T2
T1,OUT =T2,IN
front back
Conduction between disks
Irradiation from concentrator
Model validation at NREL
Particle feeder
Attenuator
Secondary concentrator
Reactor
SiC tubes
Validation with no particles, just Ar
Some runs with particles
Used attenuator to test power levels (2, 3, 4, 5, 6 kW)
Recorded transients
Model validation during transients
Front Wall Temperature at the center of the tube:
3 kW
1258 K
1256 K τ= 85 s
Dynamic model of the reactor
CARBON STEAM GASIFICATION REACTION:
C(s) + H2O (g) CO (g) + H2 (g)
Considered also water-gas shift reaction:
CO(g) + H2O (g) CO2 (g) + H2 (g)
Kinetics taken from literature
Experimental runs at NREL to choose best-fitting kinetics
Carbon rate of reaction: 𝑟𝑐𝑎𝑟𝑏𝑜𝑛 =-(𝑟𝑐𝑜 + 𝑟𝑐𝑜2)
Dynamic model of the reactor
RESULTS FOR A PARTLY CLOUDY DAY
REFLECTIVE CAVITY ABSORBING CAVITY
τ=552 seconds τ=12 seconds
Summary
A simplified dynamic model was developed and implemented in MATLAB
Model was validated with experimental runs at NREL
The model will be used in a MPC algorithm to control flow rates in response to changes in solar irradiation
Error in the model is less than 5% in terms of the steady state temperatures
14 CSREES 68-3A75-7-605
Acknowledgements