A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Rotary kilns with sectional internals & lifters - Industrial process example of iron oxide pigment production -
Rotary kilns are widespread and common in the thermal processing of solid material. This thesis deals with the exemplary calcination process in the rotary kiln during iron oxide pigment production according to the Laux process. The rotary kiln process is considered in its entirety, but particular attention is paid to the special design of the kiln/reactor with various internals and their effects. The core of the investigations is the analysis of the axial and transverse solids transport in a rotary drum with lifters and in particular with sectional internals. The overall approach is based on the decomposition of the kiln process into its individual phenomena (reactions, solid transport, heat transport) and the subsequent combination of the findings in a mathematical model. In the investigation of the "Reactions in iron oxide conversion" (Part II) the reaction kinetics is analyzed experimentally. It could be found that the oxygen concentration (in a technically relevant range > 10 vol.% O2) and heating rates (up to 20 K/min) do not impact the kinetics. Different kinetic behavior of magnetites prepared from different iron salts as well as for the industrial Laux magnetites could be shown. A high influence of the Fe2+/Fe3+-ratio of the magnetite educt, especially on the heat balance of the reaction (enthalpy of oxidation) was found. The core part of the thesis "Solid transport in rotary drums" (Part III) focuses on the solid transport processes in rotary drums. A higly modular and flexible rotary drum apparatus construced in PMMA was developed to investigate the solid transport experimentally utilizing optical methods. Regarding the axial solid transport, sectional internals increase the residence time but reduce the drum capacity while the axial dispersion coefficients are similar to the bare drum. The influences of sectional internals depend on the length and number of sections, which was quantified in an empirical equation. Furthermore, the Saeman-model has been adapted successfully to describe rotary drums ...
Rotary kilns with sectional internals & lifters - Industrial process example of iron oxide pigment production -
Rotary kilns are widespread and common in the thermal processing of solid material. This thesis deals with the exemplary calcination process in the rotary kiln during iron oxide pigment production according to the Laux process. The rotary kiln process is considered in its entirety, but particular attention is paid to the special design of the kiln/reactor with various internals and their effects. The core of the investigations is the analysis of the axial and transverse solids transport in a rotary drum with lifters and in particular with sectional internals. The overall approach is based on the decomposition of the kiln process into its individual phenomena (reactions, solid transport, heat transport) and the subsequent combination of the findings in a mathematical model. In the investigation of the "Reactions in iron oxide conversion" (Part II) the reaction kinetics is analyzed experimentally. It could be found that the oxygen concentration (in a technically relevant range > 10 vol.% O2) and heating rates (up to 20 K/min) do not impact the kinetics. Different kinetic behavior of magnetites prepared from different iron salts as well as for the industrial Laux magnetites could be shown. A high influence of the Fe2+/Fe3+-ratio of the magnetite educt, especially on the heat balance of the reaction (enthalpy of oxidation) was found. The core part of the thesis "Solid transport in rotary drums" (Part III) focuses on the solid transport processes in rotary drums. A higly modular and flexible rotary drum apparatus construced in PMMA was developed to investigate the solid transport experimentally utilizing optical methods. Regarding the axial solid transport, sectional internals increase the residence time but reduce the drum capacity while the axial dispersion coefficients are similar to the bare drum. The influences of sectional internals depend on the length and number of sections, which was quantified in an empirical equation. Furthermore, the Saeman-model has been adapted successfully to describe rotary drums ...
Rotary kilns with sectional internals & lifters - Industrial process example of iron oxide pigment production -
Prießen, Joscha (author) / Behrens, Malte
2023-03-29
Theses
Electronic Resource
English
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