From Flue Gas to Liquid CO₂: Evaluating Impurity Profiles and Quality Control in Waste Incineration-based Capture: Case ECCU
Kulmala, Miikka (2025)
2025
Energiamurroksen DI-ohjelma - Master’s Programme in Energy Transition
Informaatioteknologian ja viestinnän tiedekunta - Faculty of Information Technology and Communication Sciences
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Hyväksymispäivämäärä
2025-11-07
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-2025110610426
https://urn.fi/URN:NBN:fi:tuni-2025110610426
Tiivistelmä
The main goal of this master’s thesis was to research, based on preliminary design and literature review, how emissions from waste incineration might affect the final product of the proposed CO2 capture and liquefaction plant. There was limited research on the master’s thesis topic, namely the flow of emissions from waste incineration through the CO2 capture and liquefaction processes into the final product, as well as their effects on the quality of liquefied carbon dioxide (LCO2). Furthermore, there is no universally applicable quality for LCO2, making it essential to examine the quality on a case-by-case basis. Therefore, this research focused on the maximum emission scenarios at the waste incineration (worst-case).
The research involved a literature review and a case study, where an individual case was examined in detail, and based on it, the transportation of impurities through the capture and liquefaction processes was analysed. In the literature review section, a general understanding of waste incineration, CO2 capture, and liquefaction processes was established. Furthermore, the LCO2 quality specifications, waste incineration emission reporting, and their connection were clarified following the literature review. Based on the literature and case plant characteristics, the expected normal operation for the plant was defined, including the process, its conditions, input values and LCO2 quality specifications. During the formation of the overall process, notable gaps in the literature were identified regarding emission purification throughout the capturing and liquefaction processes. This led to impurity concentrations being calculated as a pass-through, assuming the concentrations remain unchanged throughout the capturing and liquefaction. For process parameters, the concentrations were evaluated to obtain results comparable with the LCO2 quality specifications. The impacts of emission spikes were assessed through two worst-case scenarios representing maximum conditions, where the emission limit values specified in the environmental limits were used: Scenario 1 used daily limits for continuously measured emissions or limits for periodic spot measurements, while Scenario 2 applied half-hourly limits. The results from scenarios 1 and 2 were further analysed through sensitivity analyses to identify impurities that may exceed LCO2 quality specifications even during normal operation. Since CO2 quality depends on its intended use, e.g., whether for CO2 storage or as a part of e-methanol production, the quality requirements have substances that might be neglected as part of normal waste incineration measurements. For the neglected impurities, the back-calculations were conducted. Based on case study calculations, the probability of exceedances occurring and the necessity for impurity purification were assessed.
The results of the case study indicate that emission spikes can lead to exceedances during waste incineration. Exceedances can occur for every impurity measured within the waste incineration plant if the impurity remains unchanged throughout the processes. According to the sensitivity analyses conducted, the primary focus of the measured impurities should be on NOx, SOx, NH3, Hg, PCDD/F, and CO. Nonetheless, it is essential to note that the achieved results do not take into consideration the purification steps for CO2 capture and liquefaction. To achieve more accurate results, CO2 capture, liquefaction processes and the associated purification methods should be examined in more detail. Considering future studies, the need for purification of the impurities above can be utilised to assess the purification mechanisms. Additionally, the results of the back-calculations can be utilised as a reference for future examinations of the components in question, if measurements of the impurity are performed.
The research involved a literature review and a case study, where an individual case was examined in detail, and based on it, the transportation of impurities through the capture and liquefaction processes was analysed. In the literature review section, a general understanding of waste incineration, CO2 capture, and liquefaction processes was established. Furthermore, the LCO2 quality specifications, waste incineration emission reporting, and their connection were clarified following the literature review. Based on the literature and case plant characteristics, the expected normal operation for the plant was defined, including the process, its conditions, input values and LCO2 quality specifications. During the formation of the overall process, notable gaps in the literature were identified regarding emission purification throughout the capturing and liquefaction processes. This led to impurity concentrations being calculated as a pass-through, assuming the concentrations remain unchanged throughout the capturing and liquefaction. For process parameters, the concentrations were evaluated to obtain results comparable with the LCO2 quality specifications. The impacts of emission spikes were assessed through two worst-case scenarios representing maximum conditions, where the emission limit values specified in the environmental limits were used: Scenario 1 used daily limits for continuously measured emissions or limits for periodic spot measurements, while Scenario 2 applied half-hourly limits. The results from scenarios 1 and 2 were further analysed through sensitivity analyses to identify impurities that may exceed LCO2 quality specifications even during normal operation. Since CO2 quality depends on its intended use, e.g., whether for CO2 storage or as a part of e-methanol production, the quality requirements have substances that might be neglected as part of normal waste incineration measurements. For the neglected impurities, the back-calculations were conducted. Based on case study calculations, the probability of exceedances occurring and the necessity for impurity purification were assessed.
The results of the case study indicate that emission spikes can lead to exceedances during waste incineration. Exceedances can occur for every impurity measured within the waste incineration plant if the impurity remains unchanged throughout the processes. According to the sensitivity analyses conducted, the primary focus of the measured impurities should be on NOx, SOx, NH3, Hg, PCDD/F, and CO. Nonetheless, it is essential to note that the achieved results do not take into consideration the purification steps for CO2 capture and liquefaction. To achieve more accurate results, CO2 capture, liquefaction processes and the associated purification methods should be examined in more detail. Considering future studies, the need for purification of the impurities above can be utilised to assess the purification mechanisms. Additionally, the results of the back-calculations can be utilised as a reference for future examinations of the components in question, if measurements of the impurity are performed.