Session: 08-05-01: Energy-Related Multidisciplinary I

Paper Number: 145444

145444 - Kinetic Insights and Morphological Transformations in Coal Gasification: An In-Depth Analysis With Model Validation 

Understanding the reactivity and kinetics of feedstock particles is critical for process optimization, reactor design, and industrial gasifier scaling. In this study, we employed an in-house gasification setup and microscopy to investigate the coal particle mass loss and morphological changes under varying residence times in high temperature gasifier environment. The set-up aimed to emulate real-world gasification processes, resembling a fixed bed gasifier operating under atmospheric pressure conditions with a maximum temperature capability of 1100 ºC. Coal particles were crushed and sieved to achieve a narrow band particle size before being introduced into the gasifier through a feeding system. Operations were conducted after achieving different critical temperatures, i.e. de-moisturization and devolatilization limits that is near 100 °C and 550°C which attested throughout conventional TGA runs. Our analysis focused on changes in particle surface area as the particle core reaches these stipulated temperatures and the demanded   residence time. The evaluation will consider assessment of the distance from the particle center using inhouse image processing technique. This allowed us to explore how different durations of exposure to gasification conditions affected the transformation of coal particles. To mathematically model coal particle de-moisturization and devolatilization, we created model that calculates the necessary residence time required for the complete gasification. This model considers the sensitivity of the kinetic parameters and the particle size variation as the particle undergoes heating at elevated temperatures. Numerical predictions for measurable parameters, such as the change in particle radius during moisture evaporation and devolatilization, as well as temperature variations, were validated against experimental data. Results from this study provides insight in making a recipe for  the complete gasification of the solid coal particles. Furthermore, our findings indicate that heating rate influences particle size observed under standard microscopy, suggesting that microscopy offers insights into intrinsic processes involving lower diffusion and limited heat and mass transfer.

Keywords: Coal, Gasification behavior, Mathematical modelling, Residence time, Image processing, Kinetic parameter

Presenting Author: Isam Janajreh Khalifa University

Presenting Author Biography: The focus of Isam Janajreh's group is on thermochemical conversion of solid hydrocarbons materials into an added value fuel, biodiesel production and desalination. My Waste to Energy group characterized different waste stream feedstock (industrial, petcoke, biomass, sludge, compost, plastic, rubber, papers, and mixed waste), and convert them into chemical and thermal energy. We set up experimental for waste stream materials characterization, reactive flow, and develop conversions kinetics mechanisms using -STA, Elemental Analyzers, MS/GC/ICP and Drop Tube reactor additional to small scale gasifiers, pyrolyzers. We simulate and develop predictive tools for:
 Systematic based on Equilibrium elemental reactions as well as Gibbs Energy minimization in a well-stirred reactor
 High fidelity multiple species reactive flow based on transport, continuous and discrete phase flow utilizing CFD.
 Develop chemical kinetics, applied to particle devolatalization, chat combustion, pyrolysis and transesterification
 Integrate the performance/balance of power plant units in an optimized configuration and combined cycles including IGCC, ISSCC and other types of hybrid/co-generation power plants.
My main activities are: (i) Analytical chemistry feedstock characterization, (ii) systematic and equilibrium chemical conversion analyses, (iii) detailed and coupled chemically reactive flow analyses of the combustion, gasification, and pyrolysis, and (iv) integrated process simulation and balance of the power plant. This is conducted by integrating the detailed coupled analysis into the plant flow sheet utilizing 1st and 2nd thermodynamics laws.
Desalination, Wind Energy, and Thermo-acoustics are another active research areas in my lab that are involved advanced flow molding and simulation. In these three areas we develop high fidelity predictive models with conjugated heat and multiple species heat for the flow in porous media for Direct Contact Membrane Distillation, muti-stage flashing desalination, freeze desalination, as well as multiple rotating flow for turbine rotors. We also setup multiple experimental validations for performance prediction and enhancement for freeze desalination and thermoacoustics. Currently we are exploring freeze desalination as low energy desalination option and setup experimentally and running high fidelity process modeling. Extracting enhanced wind energy from HAWT and VAWT have been part of investigation and now we are start looking into the induced flow vibration on structure for their reliability and also as potential for energy harvesting.

Authors:

Haider Khan Khalifa University
Symeon Savvopoulos Khalifa University
Isam Janajreh Khalifa University