Effect of Operating Conditions on Cryogenic Carbon Dioxide Removal

Abstract

In this investigation, a natural‐gas (NG) treatment system for NG sources with high CO2 content is simulated experimentally and theoretically using Aspen Plus. The concept uses patented heat exchangers and a process design developed as part of the cryogenic carbon capture(CCC) process to remove enough CO2 to enable the treated gas to be handled without the modification of traditional NG equipment. Simultaneously, the process removes liquefied natural gas (LNG) very efficiently. This process provides a simpler alternative to the solvent‐based CO2 removal, absorbent drying, and cryogenic NG liquid extraction systems found in traditional NG processing. The data from an experimental bench‐scale apparatus verify the results of the simulations as a function of NG composition and pressure. Costing parameters, exergy loss, and heat‐exchanger efficiency are also discussed. The results confirm low exergy losses for bench‐scale apparatus. The system uses heat exchangers with efficiencies of more than 90 %. High pressure and low methane content in the NG result in high CO2 capture.

Review of Cryogenic Carbon Capture Innovations and Their Potential Applications

“…As an alternative to heat exchangers, the flue gas containing CO 2 can be directly contacted with a cryogenic liquid, causing the flue gas to form solid CO 2 particles in a staged desublimating column. The CO 2 that is dissolved in the contacting liquid will form a slurry, which then goes through filtration and will subsequently provide a CO 2 pure product [19,20]. The contact liquid is used to provide cooling by direct contact whilst preventing CO 2 from freezing on surfaces and to aid in the transport of frost CO 2 as a slurry.…”

“…The contact liquid is used to provide cooling by direct contact whilst preventing CO 2 from freezing on surfaces and to aid in the transport of frost CO 2 as a slurry. Isopropane has been chosen based on holding low the vapour pressures need to be to minimise losses by evaporation [20]. Since solid CO 2 is filtered, the contact liquid can be recycled with the aim of creating a closed loop, and only a slight loss of contact liquid is anticipated.…”

Electrochemistry‐Based CO2 Removal Technologies

“…[15] Newer CO 2 capture technologies transition from thermal to electrical CO 2 capture systems and include pressure swing adsorption (PSA) (21-75 kJ mol À 1 CO 2 [16,17] ) and membrane applications where electricity is used for high pressure pumping and vacuum. [18] It also includes cryogenic freezing out of CO 2 as dry ice in a heat pump approach, driven electrically by compressors [19] (51-79 kJ mol À 1 CO 2 [20] ). In general, these electrical methods are to a large extent limited by mechanical and thermodynamic effects resulting from high pressure requirements.…”

Flexible Carbon Capture and Utilization technologies in future energy systems and the utilization pathways of captured CO2

“…Solution enriched with the CO2 molecules is then introduced to the stripper column to release captured CO2 [119]. As an absorbents metal carbonates can be used as well, but their price significantly affects wider usage of them [120]. Process is highly efficient in terms of capturing CO2 and efficiency can be up to 98%.…”