Sequence-based Process Modeling of Fluidized Bed Biomass Gasification

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• 作者：Hamid Asadi-Saghandi ; Amir Sheikhi ; Rahmat Sotudeh-Gharebagh
• 刊名：ACS Sustainable Chemistry & Engineering
• 出版年：2015
• 出版时间：November 2, 2015
• 年：2015
• 卷：3
• 期：11
• 页码：2640-2651
• 全文大小：766K
• ISSN：2168-0485

文摘

Despite tremendous effort to model fluidized bed biomass gasifiers, as major sustainable waste-to-energy devices, current equation-oriented approaches suffer from implementation difficulties. In this research, a comprehensive cocurrent sequence-based process model is introduced to simulate bottom-fed bubbling fluidized bed biomass gasifiers (BFBGs). The gasifiers include two operating regions, namely dense bed and freeboard. The dense bed is divided into several sections of logically ordered ideal reactors to describe the behavior of interacting phases, i.e., bubble and emulsion. The bubble phase is well characterized by an ideal plug flow reactor (PFR), and the emulsion phase is simulated as a continuous stirred-tank reactor (CSTR). The freeboard is successfully mimicked with a PFR. Hydrodynamic and kinetic submodels describe physical and chemical phenomena taking place in the gasifiers, respectively. A dynamic two phase model is adopted as the hydrodynamic submodel, and the kinetic submodel is derived from the literature. Several sets of experimental data from biomass gasifiers with various biomass feedstocks are analyzed to evaluate the reliability of the proposed model. Close agreement between the experimental data and the model shows that the proposed simple and in-hand method is able to predict the behavior of complex BFBGs. Finally, the modeling package is used to optimize the hydrogen production, H₂/CO, and hazardous gas emission in BFBGs. The proposed model can be integrated into the industrial process simulators such as AspenOne modules to represent highly nonideal reactors.