One-dimensional numerical analysis of CO2 capture by desublimation in an isopentane spray tower
[Objective]Carbon capture technology is a focal point in the realm of carbon capture,utilization,and storage.Enhancing CO2 capture efficiency and reducing energy consumption are pivotal for the viability of industrial applications and the attainment of the"carbon peaking and carbon neutrality"objective.Cryogenic CO2 capture by desublimation is a post-combustion capture technology that has the advantages of high CO2 capture rate,environmental friendliness,and the production of high-purity CO2 products.Consequently,it holds substantial potential for both academic research and industrial applications.Nevertheless,conventional CO2 desublimation capture methods using solid media present limitations,including challenges in collecting and removing solid CO2,compromised heat transfer between solid media and gaseous CO2,and corrosion issues.Although utilizing liquid media for desublimating and capturing CO2 can overcome these challenges,pertinent research remains insufficient.[Methods]This study employs the cryogenic carbon capture method,utilizing liquid media to desublimate CO2.It establishes a one-dimensional model for the isopentane spray tower to examine the temperature and CO2 concentration fields within the tower.The aim is to elucidate the relationships and physical mechanisms governing the tower's overall CO2 capture rate in relation to the initial conditions of the inlet gas,isopentane droplets,and spray tower settings.[Results]Numerical results from the one-dimensional isopentane spray tower revealed the following:(1)The temperature variation of isopentane droplets was minimal and primarily occurs around the gas inlet area,indicating that desublimation was contingent upon CO2 concentration fields and mass diffusion.(2)The temperature of the CO2 mixture gas undergone significant changes throughout the tower at a constant rate,highlighting the dominance of gas temperature fields by thermal convection with negligible effects from droplet desublimation on gas temperature.(3)The initial diameters and temperatures of isopentane droplets significantly affected the spray tower's overall CO2 capture rate.Initial diameters smaller than 2.0-mm and initial temperatures below 150.00 K for isopentane droplets result in a CO2 capture exceeding 90％for a 2.0-m high spray tower,validating the efficacy and efficiency of the isopentane spray tower in cryogenic CO2 capture.(4)The spray tower's overall CO2 capture rate was influenced by the tower's height,initial velocity and temperature of isopentane droplets,and inlet gas velocities.The efficiency of the desublimation process was strongly dependent on the heat transfer efficiency and contact time between isopentane droplets and CO2 mixture gases.[Conclusions]Through numerical simulation and investigation of temperature and CO2 concentration fields within the isopentane spray tower,this study unveils and analyzes factors influencing the tower's CO2 capture rate and the pertinent mechanisms of CO2 desublimation on liquid droplets.Additionally,it demonstrates the effectiveness of the isopentane spray tower in capturing CO2,emphasizing the substantial potential for cryogenic CO2 capture using liquid spray in the field of carbon capture.
isopentane spray towercryogenic CO2 capture technologydesublimationnumerical simulation
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