Total shipping carbon emissions were approximately 938 million tonnes CO2 in 2012. Zero emission shipping options rely on the use of electricity or alternative fuels, such as blue hydrogen or ammonia. However, that requires major modifications to the ships and the logistics of fuel distribution. As a transition solution, which can be implemented on much shorter term; this study presents the technical and economic evaluation for ship-based carbon capture (SBCC) on diesel or LNG-fuelled vessels. Two reference ship engines of 1280 kW and 3000 kW were chosen. The process is simulated using Aspen Plus®, with 30 wt% aqueous monoethanolamine (MEA) and 30 wt% aqueous piperazine (PZ) as solvents. CAPEX and OPEX were reduced by integrating the thermal energy of the exhaust gas with the stripper reboiler for the diesel and LNG powered ships. For the LNG ships, the cooling capacity from evaporation of LNG was used for liquefying the captured CO2. By using piperazine, which allows CO2 to be desorbed at higher pressure than MEA, the minimal cost of CO2 captured achieved was 98 €/tonne CO2 with a corresponding 1.8 million euros equipment cost for the 3000 kW engine ship. Additionally, the feasibility of SBCC is investigated by adapting an existing cargo ship design (powered by the reference 3000 kW engine) for including the carbon capture process equipment. The capture, compression and storage units are fitted onboard, and the design is modified so that the transport capacity remains the same, while maintaining the ship stability.@en

This article presents a thermodynamic and kinetic characterization of CO2 absorption by 30 aqueous amine solutions. A solvent screening setup (S.S.S.) was used to find the CO2 loading (α) for 30 different aqueous amine solutions (30 wt%) at a pressure of 1 bar with feed gas containing 15 vol% CO2 and 85 vol% N2 at 313.15 K to provide reliable absorber parameters. The structures of various amines (linear, non-linear, polyamines, sterically hindered, etc.) were tested and the S.S.S. results showed that hexamethylenediamine (HMD) has higher CO2 loading at 1.35 moles of CO2/mole of amine, and triethanolamine (TEA) has the lowest at 0.39 mole of CO2/mole of amine. The heat of absorption indicates that MDEA has the lowest and HMD has the highest at −52.51 kJ/mole of CO2 and −98.39 kJ/mole of CO2, respectively. The combined data for the CO2 loading and the absorption heat generated 6 amines that have good properties for the post-combustion CO2 capture process in comparison with that of MEA. These amines are made up of one secondary amine (2-ethylaminoethanol, 2EAE) and 5 tertiary amines (N-methyldiethanolamine, MDEA, 1-dimethylamino-2-propanol, 1DMA2P, 2-dimethylaminoethanol, 2DMAE, 3-dimethylamino-1-propanol, 3DMA1P and N,N,N′,N′-tetramethyl-1,3-propanediamine, TMPDA). In comparison with the amine reference MEA (ΔH = −85.13 kJ/mole of CO2 and α = 0.58 mole CO2/mole of amine), the 6 amines have heats of absorption that are between −68.95 kJ/mole of CO2 and −52.51 kJ/mole of CO2, and their CO2 loading is between 0.52 and 1.16 mole of CO2/mole amine. The third important parameter, namely the reaction kinetics between aqueous amine solutions and CO2, was studied by using stopped-flow equipment to measure the pseudo-first order reaction (k0, s−1) at different amine concentrations. A determination of the second order rate constants (k2, m3 mole−1 s−1) at 298.15, 303.15, 308.15 and 313.15 K was performed by using the proposed reaction mechanisms. The base catalysis mechanism was used to correlate the experimental data of the tertiary amines and the zwitterion mechanism was used to correlate the experimental data of the primary/secondary amines. The kinetics results show that 2EAE, a secondary amine, was very high in comparison with MDEA, 1DMA2P, 2DMAE, 3DMA1P and TMPDA, all of which are tertiary amines that are very close to MEA, which is the reference case. This result shows that 2EAE is a good candidate for CO2 capture as an alternative to MEA because it has good CO2 absorption, a low heat of absorption and high kinetic reaction with CO2. Moreover, the outcomes for the thermodynamic and kinetic properties indicate that the following 5 amine blends have emerged from this study: 2EAE/MDEA, 2EAE/1DMA2P, 2EAE/2DMAE, 2EAE/3DMA1P and 2EAE/TMPDA.@en

In this work, a perspective is given on the development lines for CO 2 post-combustion capture technology. Guidelines for cost reductions and suggestions for future research on solvent and process development are presented. By analyzing the post-combustion capture process in this work, it is evident that to achieve significant reduction of the capture process cost, multiple process parameters need to be improved. For future development of CO2 post-combustion capture process, it would be beneficial to direct the solvent development research towards solvents systems, which have lower reaction enthalpy and higher solvent capacity. A significant improvement can be obtained by the development of solvent systems where the solvent is regenerated at higher pressure. In addition, smart process improvement and integration are required to achieve a reasonable cost reduction. It can be expected that by improving the process design and the solvent, implementation of post combustion capture on larger scale will be possible in the near future.@en

Oxidative degradation is a serious concern for upscaling of amine-based carbon capture technology. Different kinetic models have been proposed based on laboratory experiments, however the kinetic parameters included are limited to those relevant for a lab-scale system and not a capture plant. Besides, most of the models fail to recognize the catalytic effect of metals. The objective of this work is to develop a representative kinetic model based on an apparent auto-catalytic reaction mechanism between solvent degradation, corrosion and ammonia emissions. Measurements from four different pilot plants: (i) EnBW's plant at Heilbronn, Germany (ii) TNO's plant at Maasvlakte, The Netherlands; (iii) CSIRO's plants at Loy Yang and Tarong, Australia and (iv) DONG Energy's plant at Esbjerg, Denmark are utilized to propose a degradation kinetic model for 30 wt % ethanolamine (MEA) as the capture solvent. The kinetic parameters of the model were regressed based on the pilot plant campaign at EnBW. The kinetic model was validated by comparing it with the measurements at the remaining pilot campaigns. The model predicted the trends of ammonia emissions and metal concentration within the same order of magnitude. This study provides a methodology to establish a quantitative approach for predicting the onset of unacceptable degradation levels which can be further used to devise counter-measure strategies such as reclaiming and metal removal.@en

The present study has established the direct pseudo–first-order reaction kinetics of different aqueous-based single and blended amines over the temperature range of 298.15-313.15 K using stopped-flow techniques. The single amines include one primary amine (monoethanolamine, MEA), two secondary amines (diethanolamine, DEA and 2-ethyl(amino)ethanol, 2EAE), four tertiary amines (N-methyldiethanolamine, MDEA, 1-dimethylamino-2-propanol, 1DMA2P, 3-dimethylamino-1-propanol, 3DMA1P, and 2-dimethylaminoethanol, 2DMAE), one sterically hindered amine (2-amino-2-methyl-1-propanol, AMP), and one cyclic diamine (piperazine, PZ). The blend systems used are MEA/PZ, DEA/PZ, MDEA/PZ, AMP/PZ, MEA/AMP, MDEA/2EAE, 1DMA2P/2EAE, 3DMA1P/2EAE, and 2DMAE/2EAE. Different reaction mechanisms for the reaction of CO2 with aqueous solutions of amines, such as base-catalysis, zwitterion, termolecular, hybrid of zwitterion, hybrid of base-catalysis-zwitterion, and hybrid of base-catalysis-termolecular reaction mechanisms, are used to correlate the experimental data. For the single amines, the zwitterion mechanism is well suited to fit the experimental data of primary, secondary, sterically hindered and cyclic amines with an absolute average deviation (AAD%) less than 5%. The base-catalysis mechanism fits the experimental data of all the tertiary amines well with an AAD less than 5%. For the blends, the hybrid of zwitterion mechanism fits the experimental data of MEA/PZ, DEA/PZ, AMP/PZ, and MEA/AMP well with an AAD less than 5%, whereas the hybrid of base-catalysis-zwitterion mechanism fits the experimental data of MDEA/PZ, MDEA/2EAE, 1DMA2P/2EAE, 3DMA1P/2EAE, and 2DMAE/2EAE well with an AAD less than 5%.@en