2 Dynamic Modelling of Reactive Fluidized Bed Systems Using …
63
4 Conclusion
Dynamic models, necessary for CLC with gaseous and solid fuels, were implemented
into the flowsheet simulation environment DYSSOL. Unit models for a CFB riser
reactor, a bubbling bed reactor, a cyclone and a loop seal were developed. For validation, the simulations were compared with experimental data obtained from a 25 kWth
two-stage CLC pilot plant, which is operated at Hamburg University of Technology.
The dynamic models were used to simulate several hot operations of the CLC plant
with methane and wood biomass as fuel. In the following, the most important results
of the present work are summarized:
• Solid distributions in the system could be predicted close to the experimental
measurements for different operation states. The transition time from one fluid
mechanical state to another was correctly predicted.
• Heterogenous chemical reactions were implemented into the fluidized bed reactor
model, including the conversion of fuel gases with the OC and the gasification of
solid char.
• During solid combustions, the fluidized bed reactor model is able to depict the
gas conversion at the reactor exit. The simulations showed expected axial gas
concentrations over height. Nevertheless, fitted kinetic parameters needed to be
used for the simulation.
• Dynamic operation changes were applied to the system. In a hot plant run, fuel
starts and stops as well as a load change were conducted. The resulting experimental changes of the OC conversion could be accurately predicted in the simulation.
Furthermore, the response time of the OC conversion to the operation changes
could be correctly determined.
• In all simulations, a desktop computer (single core of Intel
® Core™ i7-6800 K)
could simulate the plant operation faster than in real time. This makes model-based
plant control of a complex interconnected system possible.
• DYSSOL proved to be a reliable and mighty tool to calculate units and predict
long term effects in solids processes.
References
1. Porrazzo, R., White, G., Ocone, R.: Aspen Plus simulations of fluidised beds for chemical
looping combustion. Fuel 136, 46–56 (2014)
2. Mukherjee, S., Kumar, P., Yang, A., Fennell, P.: A systematic investigation of the performance
of copper-, cobalt-, iron-, manganese- and nickel-based oxygen carriers for chemical looping
combustion technology through simulation models. Chem. Eng. Sci. 130, 79–91 (2015)
3. Li, F., Zeng, L., Velazquez-Vargas, L.G., Yoscovits, Z., Fan, L.-S.: Syngas chemical looping
gasification process: bench-scale studies and reactor simulations. AIChE J. 56, 2186–2199
(2010)
63
4 Conclusion
Dynamic models, necessary for CLC with gaseous and solid fuels, were implemented
into the flowsheet simulation environment DYSSOL. Unit models for a CFB riser
reactor, a bubbling bed reactor, a cyclone and a loop seal were developed. For validation, the simulations were compared with experimental data obtained from a 25 kWth
two-stage CLC pilot plant, which is operated at Hamburg University of Technology.
The dynamic models were used to simulate several hot operations of the CLC plant
with methane and wood biomass as fuel. In the following, the most important results
of the present work are summarized:
• Solid distributions in the system could be predicted close to the experimental
measurements for different operation states. The transition time from one fluid
mechanical state to another was correctly predicted.
• Heterogenous chemical reactions were implemented into the fluidized bed reactor
model, including the conversion of fuel gases with the OC and the gasification of
solid char.
• During solid combustions, the fluidized bed reactor model is able to depict the
gas conversion at the reactor exit. The simulations showed expected axial gas
concentrations over height. Nevertheless, fitted kinetic parameters needed to be
used for the simulation.
• Dynamic operation changes were applied to the system. In a hot plant run, fuel
starts and stops as well as a load change were conducted. The resulting experimental changes of the OC conversion could be accurately predicted in the simulation.
Furthermore, the response time of the OC conversion to the operation changes
could be correctly determined.
• In all simulations, a desktop computer (single core of Intel
® Core™ i7-6800 K)
could simulate the plant operation faster than in real time. This makes model-based
plant control of a complex interconnected system possible.
• DYSSOL proved to be a reliable and mighty tool to calculate units and predict
long term effects in solids processes.
References
1. Porrazzo, R., White, G., Ocone, R.: Aspen Plus simulations of fluidised beds for chemical
looping combustion. Fuel 136, 46–56 (2014)
2. Mukherjee, S., Kumar, P., Yang, A., Fennell, P.: A systematic investigation of the performance
of copper-, cobalt-, iron-, manganese- and nickel-based oxygen carriers for chemical looping
combustion technology through simulation models. Chem. Eng. Sci. 130, 79–91 (2015)
3. Li, F., Zeng, L., Velazquez-Vargas, L.G., Yoscovits, Z., Fan, L.-S.: Syngas chemical looping
gasification process: bench-scale studies and reactor simulations. AIChE J. 56, 2186–2199
(2010)