Expert in Modeling & Simulation of Thermal/Fluids Energy Components / Systems for Green Transition, ranked among the World’s Top 1% of Scientists across All Fields, according to the Career-Long Citation Impact (https://elsevier.digitalcommonsdata.com/datasets/btchxktzyw/6)
ABSTRACT Calcination of kaolinite particles under appropriate conditions to produce materials tha... more ABSTRACT Calcination of kaolinite particles under appropriate conditions to produce materials that can replace part of the CO2 intensive clinker is gaining an increasing interest in cement industry worldwide. This paper presents a study of flash calcination of kaolinite rich clay particles in a pilot scale gas suspension calciner, with the aim to derive useful guidelines on smart calcination for obtaining products of the best pozzolanic properties. Calcination tests are performed in the calciner under six different operation conditions. The raw feed and the calcined clay samples are all characterized experimentally and a mathematical model is also developed to predict the conversion of the clay particles. The model properly accounts for the particle–ambient flow interaction and numerically solves all the processes occurring within the clay particles. The model predictions are compared against the experimental results. A good agreement is achieved. Finally, a model-based sensitivity analysis is conducted.
This paper discusses the development of user defined FLUENT™ sub models to improve the modelling ... more This paper discusses the development of user defined FLUENT™ sub models to improve the modelling capabilities in the area of large biomass particle motion and conversion. Focus is put on a model that includes the influence from particle size and shape on the reactivity by resolving intra-particle gradients. The advanced reaction model predicts moisture and volatiles release characteristics that differ significantly from those found from a 0-dimensional model partly due to the processes occurring in parallel rather than ...
Biomass gasification is still a promising technology after over 30 years' research and develo... more Biomass gasification is still a promising technology after over 30 years' research and development and has success only in a few niche markets. In this paper, a comprehensive mathematical model for biomass particle gasification is developed within a generic particle framework, assuming the feed is a woody biomass pellet. The particle is discretized into a number of cells along radical direction, on each of which the gas governing equations are numerically solved by using the finite volume method (FVM). FVM is used to solve transport equations of each process. All the key processes, e.g., moisture evaporation, pyrolysis, heterogeneous char reactions, intra-particle heat and mass transfer, and changes in thermos-physical properties and so on, are properly taken into account to update the densities of various solid/liquid components in each cell as well as to provide source terms to the relevant gas-phase governing equations. For the source term, different chemical reactions are assumed, the density, the species, the velocity, the temperature changes, the size of pellet, et al. will be studied and calculated in the end of the project.
Ignition and burnout of a single biomass particle were studied numerically. A one-dimensional par... more Ignition and burnout of a single biomass particle were studied numerically. A one-dimensional particle combustion model was developed which is capable to simulate all the intraparticle conversion processes (drying, recondensation, devolatilization, char gasification/oxidation and heat/mass/momentum transfer) to investigate the conversion and ignition process of single biomass particle. The results indicated that the ignition occurrs homogeneously in all cases. Also the results showed that the homogeneous ignition delay ...
Co-firing biomass with coal or gas in the existing units has gained increasing interest in the re... more Co-firing biomass with coal or gas in the existing units has gained increasing interest in the recent past to increase the production of environmentally friendly, renewable green power. In this paper, co-firing biomass with natural gas in a 10m long wall-fired burner model is studied numerically. To better understand biomass co-firing and therefore improve the design for co-firing biomass in wall-fired burners, the most commonly used spherical particle shape assumption is not used here, which may deviate a lot from reality for big biomass ...
A sample of 1.2 kg Danish wheat straw (Jutland, 1997) prepared for suspension firing in a PF boil... more A sample of 1.2 kg Danish wheat straw (Jutland, 1997) prepared for suspension firing in a PF boiler has been analyzed for the purpose of generating size and shape distribution functions applicable to numerical modelling of combustion processes involving biomass, characterised by highly anisotropic shapes. The sample is subdivided by straw type, and coherent size, type and mass distribution parameters are reported for the entire sample. This type of data is necessary in order to use CFD reliably as a design and retrofit tool for co- ...
ABSTRACT Kaolinite rich clay particles calcined under certain conditions can attain favorable poz... more ABSTRACT Kaolinite rich clay particles calcined under certain conditions can attain favorable pozzolanic properties and can be used to substitute part of the CO2 intensive clinker in cement production. To better guide calcination of a clay material, a transient one-dimensional single particle model is developed, which fully addresses the conversion process of raw kaolinite particles suspended in hot gas. Particles are discretized into a number of spherical cells, on each of which mass, momentum, energy and species conservation equations are numerically solved by using the finite volume method. Reactions considered in the model include dehydration, dehydroxylation and various phase transformations. Thermogravimetric analysis is used to determine reaction kinetic data required as inputs in the model and to validate the model. Finally, model-based sensitivity analysis is performed, from which quantitative guidelines for calcination condition optimization are derived.
ABSTRACT Calcination of kaolinite particles under appropriate conditions to produce materials tha... more ABSTRACT Calcination of kaolinite particles under appropriate conditions to produce materials that can replace part of the CO2 intensive clinker is gaining an increasing interest in cement industry worldwide. This paper presents a study of flash calcination of kaolinite rich clay particles in a pilot scale gas suspension calciner, with the aim to derive useful guidelines on smart calcination for obtaining products of the best pozzolanic properties. Calcination tests are performed in the calciner under six different operation conditions. The raw feed and the calcined clay samples are all characterized experimentally and a mathematical model is also developed to predict the conversion of the clay particles. The model properly accounts for the particle–ambient flow interaction and numerically solves all the processes occurring within the clay particles. The model predictions are compared against the experimental results. A good agreement is achieved. Finally, a model-based sensitivity analysis is conducted.
This paper discusses the development of user defined FLUENT™ sub models to improve the modelling ... more This paper discusses the development of user defined FLUENT™ sub models to improve the modelling capabilities in the area of large biomass particle motion and conversion. Focus is put on a model that includes the influence from particle size and shape on the reactivity by resolving intra-particle gradients. The advanced reaction model predicts moisture and volatiles release characteristics that differ significantly from those found from a 0-dimensional model partly due to the processes occurring in parallel rather than ...
Biomass gasification is still a promising technology after over 30 years' research and develo... more Biomass gasification is still a promising technology after over 30 years' research and development and has success only in a few niche markets. In this paper, a comprehensive mathematical model for biomass particle gasification is developed within a generic particle framework, assuming the feed is a woody biomass pellet. The particle is discretized into a number of cells along radical direction, on each of which the gas governing equations are numerically solved by using the finite volume method (FVM). FVM is used to solve transport equations of each process. All the key processes, e.g., moisture evaporation, pyrolysis, heterogeneous char reactions, intra-particle heat and mass transfer, and changes in thermos-physical properties and so on, are properly taken into account to update the densities of various solid/liquid components in each cell as well as to provide source terms to the relevant gas-phase governing equations. For the source term, different chemical reactions are assumed, the density, the species, the velocity, the temperature changes, the size of pellet, et al. will be studied and calculated in the end of the project.
Ignition and burnout of a single biomass particle were studied numerically. A one-dimensional par... more Ignition and burnout of a single biomass particle were studied numerically. A one-dimensional particle combustion model was developed which is capable to simulate all the intraparticle conversion processes (drying, recondensation, devolatilization, char gasification/oxidation and heat/mass/momentum transfer) to investigate the conversion and ignition process of single biomass particle. The results indicated that the ignition occurrs homogeneously in all cases. Also the results showed that the homogeneous ignition delay ...
Co-firing biomass with coal or gas in the existing units has gained increasing interest in the re... more Co-firing biomass with coal or gas in the existing units has gained increasing interest in the recent past to increase the production of environmentally friendly, renewable green power. In this paper, co-firing biomass with natural gas in a 10m long wall-fired burner model is studied numerically. To better understand biomass co-firing and therefore improve the design for co-firing biomass in wall-fired burners, the most commonly used spherical particle shape assumption is not used here, which may deviate a lot from reality for big biomass ...
A sample of 1.2 kg Danish wheat straw (Jutland, 1997) prepared for suspension firing in a PF boil... more A sample of 1.2 kg Danish wheat straw (Jutland, 1997) prepared for suspension firing in a PF boiler has been analyzed for the purpose of generating size and shape distribution functions applicable to numerical modelling of combustion processes involving biomass, characterised by highly anisotropic shapes. The sample is subdivided by straw type, and coherent size, type and mass distribution parameters are reported for the entire sample. This type of data is necessary in order to use CFD reliably as a design and retrofit tool for co- ...
ABSTRACT Kaolinite rich clay particles calcined under certain conditions can attain favorable poz... more ABSTRACT Kaolinite rich clay particles calcined under certain conditions can attain favorable pozzolanic properties and can be used to substitute part of the CO2 intensive clinker in cement production. To better guide calcination of a clay material, a transient one-dimensional single particle model is developed, which fully addresses the conversion process of raw kaolinite particles suspended in hot gas. Particles are discretized into a number of spherical cells, on each of which mass, momentum, energy and species conservation equations are numerically solved by using the finite volume method. Reactions considered in the model include dehydration, dehydroxylation and various phase transformations. Thermogravimetric analysis is used to determine reaction kinetic data required as inputs in the model and to validate the model. Finally, model-based sensitivity analysis is performed, from which quantitative guidelines for calcination condition optimization are derived.
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