Simulation of biomass char gasification in a downdraft reactor for syngas production

Abstract

A steady state, one-dimensional computational fluid dynamics model of wood char gasification in a downdraft reactor is presented. The model is not only based on reaction kinetics and fluid flow in the porous char bed but also on equations of heat and mass conservation. An original OpenFOAM solver is used to simulate the model and the results are found to be in good agreement with published experimental data. Next, a sensitivity analysis is performed to study the influence of reactor inlet temperature and gas composition on char conversion, bed temperature profile and syngas composition. In addition, the evolution of the complex reaction mechanisms involved in mixed atmosphere gasification is investigated, and the most suitable operating parameters for controlling syngas composition are evaluated. Our simulation results provide essential knowledge for optimizing the design and operation of downdraft gasifiers to produce syngas that meets the requirements of various biofuel applications.In all graphs, the experimental data provided by Teixeira et al. 24 are represented by triangles, and the predicted values from OPENFOAM and COMSOL 24 simulations are represented by solid and dashed lines, respectively. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

Co-pyrogasification of Plastics and Biomass, a Review

“…: Syngas composition for poplar wood and PE under N2, steam and CO2 [118] and H2 from char [123]. A simulation analysis by Ephraim, (2016 b ) [150] provides insight into the evolution of the complex reaction mechanisms along the char bed of a downdraft gasifier under varying concentrations of mixed reaction atmospheres (O2, H2O and CO2). Their results have shown that the reaction atmosphere strongly influences the gasification reaction rates in the gasifier entrance zone, whereby the increase in O2 concentration (0 to 3 vol%) strongly increases the rates of combustion, steam gasification, Boudouard and WGS reactions, whereas increasing H2O (5 to 20 vol%) raises only steam gasification and WGS rates.…”

“…Furthermore, CO2 (5 to 20 vol%) only affects Boudouard and WGS reaction rates. Based on their analysis, Ephraim, (2016 b ) [150] concluded that O2 and H2O atmospheres exert the most influence on the syngas composition (H2/CO ratio). Figure 9 gives the syngas composition for poplar wood and PE under N2, steam, and CO2 [118].…”

Sustainable management of plastic wastes in COVID-19 pandemic: The biochar solution

“…In addition, plastic polymers have been attempted for conversion into useful compounds through pyrolysis, gasification of thermal oxidation ( Ephraim et al, 2016 ). Nanda et al ( Li et al, 2022 ) reviewed the thermochemical conversion (e.g., including pyrolysis, gasification, and liquefaction) of plastic waste to fuels, and concluded that pyrolysis was by far the most widely researched conversion technology compared to liquefaction and gasification.…”

Interaction and Kinetics Study of the Co-Gasification of High-solid Anaerobic Digestate and Lignite

“…Co-gasification is widely adopted for the disposal of biomass and clean utilization of coal. It could not only inhibit the generation of SO x and NO x , but also reduce the emission of greenhouse gases [7,[15][16][17][18]. Coal has the advantages of high energy density and high calorific value, while the combustion of coal may lead to serious environmental pollution.…”