CPOTE2024
|
8th
International Conference on
Contemporary Problems of Thermal Engineering
23-26 September 2024 | Gliwice, Poland | Hybrid event
Contemporary Problems of Thermal Engineering
23-26 September 2024 | Gliwice, Poland | Hybrid event
Abstract CPOTE2024-1082-A
Dynamics of biomass conversion in a fixed bed – a comparison of different simulation methods based on the Eulerian-Lagrangian approach
Behrouz ADIBIMANESH, The Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, PolandSylwia POLESEK-KARCZEWSKA, The Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Poland
Izabela WARDACH-ŚWIĘCICKA, The Szewalaski Institute of Fluid Flow Machinery, Polish Academy of Sciences, Poland
Nowadays, a strong need for developing environmentally sound heat and power energy generation based on local renewable resources has led to a growing interest in small-scale technologies for biomass and biowaste conversion. Targeted on preserving low emissions, attention is focused on conversion methods to liquid or gaseous products to be further used as fuels or for the production of synthetics.
Gasification has been considered as one of the possible routes to meet current needs. The yield and quality of producer gas is an outcome of physical and chemical processes, including phase changes, heat and mass transfer and chemical reactions. It is thus affected by many parameters, including fuel physicochemical properties in the first place. Owing to limited measurement capabilities and time- and money-consuming experimentation, numerical modeling is an invaluable tool in recognizing the phenomena comprising the process and predicting the gasifier performance.
The goal of the work is to analyze the dynamics of biomass conversion in a batch downdraft gasifier while taking into account the movement of particles shrinking due to thermal decomposition. The focus is on the process dynamics in the upper reactor where the associated change in the particle size and bed structure are significant. Two in-house simulation methods, based on the coupled Euler-Lagrange approach are used. The first one involves the solution of mass balance for the bed sublayer-representative solid particles and the energy balance for the packed bed, covering thermal effects due to conduction and radiation, and pyrolysis. It is implemented in Fortran. The second one makes use of the extended discrete element method (XDEM) that coupled with Computational Fluid Dynamics (CFD) can predict the movement of the solid fuel particles undergoing thermal conversion in an external fluid field. The distribution of temperature and pyrolysis gas yield and the movement of the fuel particles, predicted via utilizing both methods are compared and discussed.
Keywords: Downdraft gasifier, Fuel particle decomposition, Thermal and flow processes, Bed movement, Euler-Lagrange approach