Cryogenic Carbon Capture of a Cement Plant Off-gas considering the Synergies of a PtX Integration: A technical and optimisation study of cryogenic solid-vapour separation
Translated title
Cryogenic Carbon Capture of a Cement Plant Off-gas considering the Synergies of a PtX Integration
Authors
Lindquist, Frede Malthe ; Holst, Kristoffer
Term
4. term
Education
Publication year
2022
Submitted on
2022-05-28
Pages
92
Abstract
This thesis evaluates Cryogenic Carbon Capture (CCC) for cement plant flue gas. CCC is a post-combustion approach that cools the exhaust to very low (cryogenic) temperatures so CO2 can be separated from other gases and impurities, then compressed up to 150 bar. The study estimates the energy required, often called energy duty, for CCC using two flue-gas cases: one based on measured (empirical) compositions and one based on a simulated (modeled) composition. The model assumes methane-fired combustion and a calcination step supplied with pure CaCO3. To gauge improvement potential, the CCC energy demand is also compared with the theoretical minimum for CO2 separation. Results indicate that strong heat integration, reusing heat within and between process units, is essential to make CCC competitive. A sensitivity analysis shows that the CO2 concentration in the flue gas is the single most influential factor for energy use. Finally, the work explores synergies between the calcination/combustion system, the CCC unit, and a Power-to-X (PtX) plant to convert captured CO2 into methane, which could in turn drive the calcination step and move the system toward self-supply.
Dette speciale undersøger Cryogenic Carbon Capture (CCC) til cementindustriens røggasser. CCC er en efterforbrændingsmetode, hvor røggassen køles til meget lave (kryogene) temperaturer, så CO2 kan adskilles fra de øvrige gasser og urenheder og derefter komprimeres til op til 150 bar. Studiet beregner det nødvendige energiforbrug (også kaldet energiindsats) for CCC med to typer røggassammensætninger: én baseret på målte, empiriske data og én baseret på en modelleret sammensætning. Modellen antager metanfyring og en kalcineringsproces forsynet med rent CaCO3. For at vurdere forbedringspotentialet sammenlignes CCC’s energibehov også med det teoretiske minimum for CO2-separation. Resultaterne peger på, at høj grad af varmeintegration, genbrug af varme på tværs af procestrin, er afgørende for at opnå et konkurrencedygtigt energiforbrug. En følsomhedsanalyse viser, at CO2-koncentrationen i røggassen er den mest dominerende faktor for energiforbruget. Endelig undersøges synergier mellem kalcinering/forbrænding, CCC-anlægget og et Power-to-X (PtX) anlæg for at omdanne den fangede CO2 til metan, som kan bruges til at drive kalcineringsreaktionen og bringe systemet tættere på selvforsyning.
[This apstract has been rewritten with the help of AI based on the project's original abstract]