Three-dimensional full-loop simulation of a dual fluidized-bed biomass gasifier

Abstract

h i g h l i g h t sCFD simulation of biomass gasification in a dual fluidized-bed. The CFD model predicts the gas composition and the reactor temperature distribution. The CFD model has been validated by experimental data. The effects of the particle size distribution and drag models have been investigated. a r t i c l e i n f o t r a c tA three-dimensional CFD model was developed to simulate the full-loop of a dual fluidized-bed biomass gasification system consisting of a gasifier, a combustor, a cyclone separator, and a loop-seal. This fullloop simulation includes the chemical kinetic modeling of biomass drying and pyrolysis, heterogeneous char reactions, and homogeneous gas-phase reactions. In the model, the gas phase is described using Large Eddy Simulation (LES) and the particle phase is described with the Multiphase Particle-In-Cell (MP-PIC) method. The simulation was performed using the GPU-accelerated computing and the simulation results were compared with the gas composition and temperature measurements from a pilot-scale biomass gasification power plant (1 MW th , 6 tons biomass/day). The independence of the accuracy of the model on mesh resolution and computational particle number was determined. The impacts of the particle size distributions (PSD) and drag models on the reactive flows were also investigated.

Magnetic tracking of a fuel particle in a fluid-dynamically down-scaled fluidised bed

“…This decreases plant efficiency owing to the additional costs associated with flue gas cleaning and increased fan operation. In contrast, in indirect gasification [26][27][28][29] and chemical looping combustion [30][31][32][33], a too high lateral mixing of the fuel leads to fuel residence times that are too short to ensure sufficient char gasification [34]. In indirect gasification units, this leads to a product gas of reduced quality and a thermal unbalance in the dual fluidized bed system, whereas in chemical looping combustion, this creates more stringent requirements for the performance of the carbon strippers to avoid CO 2 emissions.…”

Computational Fluid Dynamics Simulation of Gas–Solid Hydrodynamics in a Bubbling Fluidized-Bed Reactor: Effects of Air Distributor, Viscous and Drag Models

“…Table 1. Governing equations of momentum and continuity for gas-solid phases [20][21][22][23][24][25].…”

Experimental and numerical investigation of sands and Geldart A biomass co‐fluidization

“…Computational fluid dynamics (CFD) is another powerful tool to investigate sands–biomass fluidization since the positions and velocities of the sand and biomass particles are tracked throughout the flow. Xiong et al reviewed the widely used CFD models such as multifluid modeling, in which gas–sands–biomass are all treated as continuum phases; Euler–Lagrange–Lagrange modeling, in which gas phase is treated as continuum phase while sands and biomass are treated as discrete phase; Euler–Euler–Lagrange modeling, in which the gas phase and sands are treated as continuum phase while biomass is treated as discrete phase. The Lagrange‐based methods directly tracked the positions of particles and is convenient for the analysis of mixing .…”