Utilization of alumina-supported K2CO3 as CO2-selective sorbent: A promising strategy to mitigate the carbon footprint of the maritime sector. (March 2018)

• Record Type: Journal Article
• Authors: Erto, Alessandro; Balsamo, Marco; Paduano, Liana Pasqualina; Lancia, Amedeo; Di Natale, Francesco
• Is Part Of: Journal of CO₂ utilization. Volume 24(2018)
• Page Start: 139
• Page End: 148
• Publication Date: 2018-03
• Subjects: CO2 capture -- Naval sector -- Potassium carbonate -- Supported sorbents -- Carbonation -- Fixed-bed scale-up; Carbon dioxide -- Periodicals; Carbon dioxide -- Environmental aspects -- Periodicals; Carbon dioxide mitigation -- Periodicals; Carbon dioxide; Carbon dioxide -- Environmental aspects; Carbon dioxide mitigation; Periodicals; 628.53205
• DOI: 10.1016/j.jcou.2017.12.014
• Languages: English
• ISSNs: 2212-9820

Abstract

Highlights: K2 CO3 supported onto alumina was used for CO2 capture from model marine flue-gas. The sorbent carbonation degree monotonically decreases with the K2 CO3 content. The supported K2 CO3 can be completely regenerated with steam at 120 °C. A temperature swing carbonation/regeneration unit was scaled-up for ship retrofit. A 30% CO2 emission cut can be attained for the analyzed ship case study. Abstract: This paper investigates the application of K2 CO3 supported onto porous alumina, as sorbent for selective CO2 capture in marine applications. Alumina-functionalized sorbents were prepared by incipient wetness impregnation achieving K2 CO3 loadings from 3.6 to 14.1% wt. Carbonation tests were performed in a fixed-bed column at temperatures between 60 and 105 °C, as those typically occurring at the outlet of a scrubber and/or a waste heat recovery unit, with a model diesel engine exhaust (5% vol. CO2, 5% vol. H2 O, balance N2 ). According to the carbonate loading, the sorbents may reach conversion degrees of carbonate up to 90% and overall capture capacity up to 0.66 mol kg −1 sorbent. Experimental data showed higher conversion degree and capture capacity compared with unsupported K2 CO3, which is affected by significant intraparticle diffusion limitations. Steam regeneration tests performed in a fixed-bed column on the sorbent with 3.6% wt K2 CO3 loading revealed that a temperature of 120 °C assures almost complete recovery of captured CO2 while preserving the sorbent carbonation degree for 10 consecutive carbonation/regeneration cycles. The preliminary design of a temperature swing carbonation/regeneration unit for on-board ship installation was performed for the reference case study of a passenger ship equipped with a 4.35 MW marine engine fueled with marine gas oil and with a commercial seawater scrubber for SO2 removal. The proposed unit appeared able to cut up to 30% carbon dioxide emission by using the sorbent containing 3.6% wt K2 CO3 and operating the carbonation and regeneration stage at 60 and 120 °C, respectively.