Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
THREE-DIMENSIONAL NUMERICAL SIMULATION OF EQUIPMENT WITH A CIRCULATING FLUIDIZED BED AND AXIAL CYCLONE IN SEMI INDUSTRIAL SCALE
Submission Author:
Guilherme Maciel , MG
Co-Authors:
Guilherme Maciel, Karina Silva, Cassius Ferreira, Valério Luiz Borges, Solidônio Carvalho, Marcelo Braga dos Santos
Presenter: Marcelo Braga dos Santos
doi://10.26678/ABCM.COBEM2023.COB2023-0771
Abstract
This study is motivated by the production of synthesis gas (syngas) from gasification of refused-derived fuel (RDF) in thermochemical reactors. For this purpose, an equipment with a circulating fluidized bed transforms RDF into synthesis gas at temperatures above 800°C. The syngas produced inside is in a mixture containing fuel gas (such as: H2, CO, CxHy, CO2, O2, N2, among other elements) added of solid particles (sand and ashes). An axial cyclone was positioned inside the equipment to remove particulates dragged along the bed. Due to the size and density of the solid particles and its residence the cyclone must be designed to clean the gas, improving its quality and reducing costs with scrubbers at the same time it promotes the chemical reactions that takes long time to complete. Therefore, in this study, a vertical cylindrical with 10.56 m height and 0.95 m diameter was modeled computationally, with an internal axial cyclone measuring 9.3 m in height and 0.6 m in the largest diameter region. To simplify the problem, in this work the model does not consider thermochemical reactions. For the solid phase, 0.425 m³ of 100 mesh sand particles with a constant density equal to 1500 kg/m³ were considered. For the gas phase an air flow of 800 kg/h at 500°C was adopted. Numerical-computational models were solved using the ANSYS software, based on the classical equations of mass conservation, momentum and energy. The k-omega SST turbulence model has been applied. From the analysis of the pressure gradient, velocity profiles and the particulate removal rate, the cyclone efficiency and the pressure drop were determined. It was demonstrated that the CFD simulation of industrial cyclone can be used effectively to design it. The obtained results allowed analyze the distribution of particles inside the equipment and their passage in the axial cyclone. Based on such data, future studies will be focused on thermochemical reactions, separation efficiency, increasing the quality of syngas produced by the equipment.
Keywords
ANSYS, Gasification, cyclone, Syngas, Waste to energy
