Application of Scaling-Law and CFD Modeling to Hydrodynamics of Circulating Biomass Fluidized Bed Gasifier

Abstract

Two modeling approaches, the scaling-law and CFD (Computational Fluid Dynamics) approaches, are presented in this paper. To save on experimental cost of the pilot plant, the scaling-law approach as a low-computational-cost method was adopted and a small scale column operating under ambient temperature and pressure was built. A series of laboratory tests and computer simulations were carried out to evaluate the hydrodynamic characteristics of a pilot fluidized-bed biomass gasifier. In the small scale column solids were fluidized. The pressure and other hydrodynamic properties were monitored for the validation of the scaling-law application. In addition to the scaling-law modeling method, the CFD approach was presented to simulate the gas-particle system in the small column. 2D CFD models were developed to simulate the hydrodynamic regime. The simulation results were validated with the experimental data from the small column. It was proved that the CFD model was able to accurately predict the hydrodynamics of the small column. The outcomes of this research present both the scaling law with the lower computational cost and the CFD modeling as a more robust method to suit various needs for the design of fluidized-bed gasifiers.

Off-Gas System Scale-Up of HIsarna Iron-Making Process: A CFD-Based Approach

“…Detailed phenomenon can be implemented in CFD models with which the scale-up calculation can be performed much easier and more effective in comparison with the traditional ways. [1,5] There are quite number of CFD-assisted scale-up studies in literatures for different processes such as fermentation, [6][7][8] coal combustion, gasification and burners, [9][10][11][12] bioreactors and bubble columns, [1,5,[13][14][15][16] gas cleaning and upgrading, [17,18] spouted and fluidized beds, [11,19,20] and crystallization reactors. [21] To mention few, Azuhata et al [9] have performed a CFD-based analysis of a coal burner to scale up from laboratory to pilot scale with 25 times higher coal feed rate.…”

“…Biglari et al [12] have performed scale-up of a small-scale fluidized bed gasifier using both CFD and dimensionless numbers and reported accurate prediction of hydrodynamics and pressure drop using CFD models. Important design and operation parameters such as minimum fluidization velocity and solid velocity are accurately predicted and they have reported higher efficiency and robustness of CFD models compared to dimensionless numbers for scaling-up procedure.…”

Study of the Properties and Particulate Matter Content of the Gas from the Innovative Pilot-Scale Gasification Installation with Integrated Ceramic Filter

“…The gas produced in the gasification chamber is burned in the burner. This allows us to supply the required amount of oxygen for combustion and guarantees appropriate mixing of the gas with the air [21]. These conditions are necessary for the complete combustion with minimal emissions of NOx, CO and PAHs.…”

A new Approach for Scaling Up from a Small Cold to a Large Hot Bed for Biomass Conversion in a Bubbling Fluidized Bed Reactor

“…Understanding how the cold bed behavior is related to the behavior in an active hot bed is often a challenge in modelling and scaling up. The traditional scaling up approaches (Glicksman et al, 1993;Glicksman, 1988;Glicksman, 1984;Romero and Johanson, 1962) that have been used in many studies (Kraft et al, 2018;Biglari et al, 2016;Thapa and Halvorsen, 2014) do not consider the influence of feedstock and volatiles (i.e. biomass) on the bubbling behavior.…”