Karbonatisierung von Betonabbruch mit einem Industrieabgasstrom

Research output: ThesisMaster's Thesis

Authors

Abstract

This thesis deals with the carbonation of concrete demolition materials, a process that describes the binding of carbon dioxide as carbonate in concrete grains. An extensive literature review shows that concrete slowly carbonates to a certain depth through weathering processes, similar to minerals. Forced treatment methods can increase the carbonation potential and significantly reduce the reaction time. The research shows that factors such as temperature, relative humidity, specific surface area of the grains, proportion of paste phase and type and duration of treatment are critical. Technologies in this area are divided into direct and indirect processes, with the latter being less preferred for economic reasons despite higher CO2 absorption. In addition to the literature analysis, a patent search is carried out, which illustrates the strong interest in patenting carbonation processes. However, many of these processes are technically complex and often represent only marginal developments of the existing state of the art. Another focus of the work is the design of a pilot plant for carbonation trials. The plant will hold 15-20 kg of concrete demolition material of various qualities and grain sizes in a modular reactor and allow treatment with a CO2-rich exhaust gas stream. The design shows that considerable simplifications and assumptions have been necessary in the sizing of the plant, particularly in terms of pressure drop and temperature curve. Problems such as condensation are attempted to be solved with specific installations. Finally, a detailed proposal for carbonation experiments is given. Different treatment times from 60 to 720 minutes are used, as well as investigations on the influence of temperature on the carbonation process through insulated and non-insulated pipes. The carbonation potential is also evaluated by comparing different grain sizes. In addition to the literature analysis, a patent search is carried out, which illustrates the strong interest in patenting carbonation processes. However, many of these processes are technically complex and often represent only marginal developments of the existing state of the art. Another focus of the work is the design of a pilot plant for carbonation trials. The plant will hold 15-20 kg of concrete demolition material of various qualities and grain sizes in a modular reactor and allow treatment with a CO2-rich exhaust gas stream. The design shows that considerable simplifications and assumptions have been necessary in the sizing of the plant, particularly in terms of pressure drop and temperature curve. Problems such as condensation are attempted to be solved with specific installations. Finally, a detailed proposal for carbonation experiments is given. Different treatment times from 60 to 720 minutes are used, as well as investigations on the influence of temperature on the carbonation process through insulated and non-insulated pipes. The carbonation potential is also evaluated by comparing different grain sizes.

Details

Translated title of the contributionCarbonation of concrete demolition material with an industrial exhaust gas stream
Original languageGerman
QualificationDipl.-Ing.
Awarding Institution
Supervisors/Advisors
Award date28 Jun 2024
Publication statusPublished - 2024