Dendritic Core-Shell Macromolecules Soluble in Supercritical Carbon Dioxide

International audienceSupercritical carbon dioxide has found strong interest as a reaction medium recently.1,2 As an alternative to organic solvents, compressed carbon dioxide is toxicologically harmless, nonflammable, inexpensive, and environmentally benign.3 Its accessible critical temperature and pressure (Tc ) 31 °C, Pc ) 7.38 MPa, Fc ) 0.468 g cm-3)4 and the possibility of tuning the solvent-specific properties between the ones of liquid and gas are very attractive

Economic assessment of novel amine based CO2 capture technologies integrated in power plants based on European Benchmarking Task Force methodology

The objective of this paper is to assess the economic advantages of an innovative solvent for CO2 capture on state-of-the-art solvents. The CESAR-1 solvent, which is an aqueous solution of 2-amino-2-methyl-propanol (AMP) and piperazine (PZ), is applied both to advanced supercritical pulverised (ASC) coal and natural gas combined cycle (NGCC) power plants with post-combustion CO2 capture units. The methodology includes process model developments using commercial simulation programs, which determine the thermodynamic properties of the selected power plants and the performance of the CO2 capture units. The results show that the techno-economic benefit of CESAR-1 versus MEA is more significant for ASC than that for NGCC due to a higher concentration of CO2 in the flue gas. This follows from the fact that the switch from MEA to CESAR-1 solvents reduces the electricity cost by 4.16€/MWh in the case of the ASC plant compared to 0.67€/MWh in connection with the proposed NGCC plant. Based on the above figures, we can conclude that CESAR-1 reduces the cost of CO2 avoided compared to MEA by 6€/t CO2 and 2€/t CO2 for the selected ASC and NGCC plants respectively. In view of that, the techno-economics can be improved if the CO2 capture plant is designed to operate using the CESAR-1 absorption technology due to a reduction in the regeneration energy and the solvent recirculation rate (considering its higher CO2 net capacity). However, the variable costs of running the capture plant are higher for the CESAR-1 solvent due to the higher cost of the amines

In-Line Monitoring of the CO₂, MDEA, and PZ Concentrations in the Liquid Phase during High Pressure CO₂ Absorption

This article provides results of the <i>in situ</i> monitoring of carbon dioxide (CO₂) removal under high pressure. An aqueous solution of methyldiethanolamine (MDEA) promoted by piperazine (PZ) for absorption rate acceleration was used. This system is promising for natural gas purification. A predictive statistical model was built using the chemometrics method and measurements of density, pH, conductivity, sound velocity, refractive index, and Near Infra-Red (NIR) spectroscopy. The CO₂ capture rate ranged from 60% up to 96% at pressures in the absorber column ranging between 15 and 20 bar. The liquid stream composition was monitored at the low pressure part of a pileline at a location before a compressor stage. The concentrations of MDEA, PZ, and CO₂ were predicted in-line using different sets of the measurement devices during 3 days of the measurement campaign. The developed approach allowed for prediction of the concentrations with accuracies of 0.7% for MDEA, 0.4% for PZ, and 2.5% for CO₂

Separation by size-exclusion filtration : homogeneous catalysts applied in membrane reactors

Since none of the commercially available nano- or ultrafiltration membranes so far shows real long-term resistance against organic solvents under the reaction conditions needed for a commercially interesting hydroformylation process and since no prices are available for bulk quantities of membranes for larger scale applications, considerations about the feasibility of such processes are difficult and would be highly speculative. However, with the combined arguments of process intensification due to simultaneous product and catalyst separation, increased product purity, and the reaction engineering advantages provided by a continuous homogeneous catalysis, a rapid development can be foreseen. A lot more fundamental work is needed in order to underline the applicability, together with the development of new membrane materials showing better performance. This field is an ideal example of multidisciplinary research in which contributions from many fields is a prerequisite for success. The availability of larger quantities of solvent resistant membranes will be driven by a strong technology push in the near future