# Biomass-Based Chemical Looping Gasification: Overview and Recent Developments
## 5 Progress in Biomass Chemical Looping Gasification
### Simulation/Modeling Studies  
Simulation and modeling of the CLG system are applied for prediction, evaluation, optimization. The most common configuration of chemical looping gasification mainly comprises two interconnected fluidized bed reactors and separators. Unlike the CLC process, minimal research has been conducted regarding the simulation and modeling of CLG by this time, particularly BCLG. The modeling of the system mainly includes its reaction kinetics, heat and mass transfer, and process performance. The most challenging issue is to describe the behavior of the gas-solid interactions inside the reactors. The model normally requires the configuration of the reactors, operational parameters, and the properties of gas and solids as input parameters to derive the combination of output parameters such as pressure and temperature distribution, composition and content of the stream, and energy and process efficiencies. The simulation of the gasification process can be developed based on [132]:  
* Restricted thermodynamic equilibrium
* Kinetic mechanism
* Experimental data  
Mathematical models of the CLG process available in the literature are mostly based on the computational fluid dynamic (CFD) technique. Currently, three main methods have been developed for the CFD modeling of fluidized-bed gasifiers such as the Eulerian-Eulerian approach, the Eulerian-Lagrangian approach, and the hybrid Eulerian-Lagrangian approach [133]. An alternative simulation approach for the gasification process is neural network modeling, but this method requires extensive experimental data, thus it is not often readily available [132]. An overall summary of simulation studies is tabulated in Table 7. \begin{table}
\begin{tabular}{c c c c c} \hline
**References** & **Biomass** & **Type of OC** & **Fuel Reactor** & **Air Reactor** & **Remarks** \\ \hline \multirow{8}{*}{[PERSON] et al. [131]} & \multirow{8}{*}{Wood pellet} & Steel & Batch fluidized & \multirow{8}{*}{\(\bullet\)} & LD slag performed a high & \multirow{8}{*}{\(\bullet\)} \\  & & converter & bed & & \\  & & slag (LD slag) & 820–970 \({}^{\circ}\)C & & \\  & & & & & \\  & & & & & \\  & & & & & \\ \end{tabular}
\end{table} 
Table 6: _Cont._ \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**References** & **Biomass** & **Type of OC** & **Type of Model** & **Remarks** \\ \hline [PERSON] et al. [134] & Poultry litter & CaO and Fe\({}_{3}\)O\({}_{4}\) & ASPEN Plus (process modeling) & • The study compared the simulations of two CLG types for H\({}_{2}\) production. \\ \hline Detchusananard & Wood residue & NiO/CaO & ASPEN Plus (process modeling) & • The simulation was developed based on the second-order respond surface model to analyze the process’s energy efficiency performance. \\ \hline [PERSON] et al. [136] & Sawdust Coal/sawdust & Ilmenite & Computational methods & • The models were developed for the techno-economic evaluation of H\({}_{2}\) and power co-generation based on BCLG. The model used an ilmenite-based system to produce 400–500 MW net power with flexible H\({}_{2}\) output. \\ \hline Aghabararnejad & Biomass & Co\({}_{3}\)O\({}_{4}\)/Al\({}_{2}\)O\({}_{3}\) & ASPEN Plus (process modeling) & • The CAD system had a higher total capital investment, but the annual operating cost was lower compared to other systems. \\ \hline [PERSON] et al. [138] & Dried poplar & Iron-based (Fe\({}_{2}\)O\({}_{3}\)) & ASPEN Plus (process modeling) & • A BDCL process was developed with the three-reactor configuration based on a multistage model to simulate the performance of the process. \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Summary of the key information of recent simulation studies in BCLG. [PERSON] et al. [134] simulated two chemical looping gasification types using the ASPEN Plus simulation software for H\({}_{2}\) production. The research aimed to compare the performance of two systems.