Current status and future development of solvent-based carbon capture

Solvent-based carbon capture is the most commercially-ready technology for economically and sustainably reaching carbon emission reduction targets in the power sector. Globally, the technology has been deployed to deal with flue gases from large scale power plants and different carbon-intensive industries. The success of the technology is due to significant R&D activities on the process development and decades of industrial experience on acid gas removal processes from gaseous mixtures. In this paper, current status of PCC based on chemical absorption—commercial deployment and demonstration projects, analysis of different solvents and process configurations—is reviewed. Although some successes have been recorded in developing this technology, its commercialization has been generally slow as evidenced in the cancellation of high profile projects across the world. This is partly due to the huge cost burden of the technology and unpredictable government policies. Different research directions, namely new process development involving process intensification, new solvent development and a combination of both, are discussed in this paper as possible pathways for reducing the huge cost of the technology

SPATIAL DATA UNCERTAINTY IN A WEBGIS TOOL SUPPORTING SEDIMENTS MANAGEMENT IN WALLONIA

This paper describes a WebGIS prototype developed for the Walloon administration to improve the communication and the management of sediments dredging actions carried out in rivers and lakes. In Wallonia, levelling dredged sediments on banks requires an official authorization from the administration. This request refers to geospatial datasets such as the official land use map, the cadastral map or the distance to potential pollution sources. Centralising geodatabases within a web interface facilitate the management of these authorizations for the managers and the central administration. The proposed system integrates various data from disparate sources. Some issues in map scale, spatial search quality and cartographic visualisation are discussed in this paper with the solutions provided. The prototype web application is currently discussed with some potential users in order to understand in which way this tool facilitate the communication, the management and the quality of the authorisation process. The structure of the paper states the why, what, who and how of this communication tool with a special focus on errors and uncertainties

Carbon Monoliths in Adsorption-based Post-combustion CO2 Capture

13th International Conference on Greenhouse Gas Control Technologies, GHGT-13, 14-18 November 2016, Lausanne, SwitzerlandThe development of adsorption-based technologies for post-combustion CO2 capture requires finding an adsorbent with adequate equilibrium and transport properties. Structured adsorbents are appealing for fixed-bed TSA processes, because they present lower pressure drop and higher thermal conductivity than conventional adsorbent beds, which facilitates the use of higher flowrates and shorter cycle times, maximizing throughput. In this work, the equilibrium of adsorption of the main flue gas components, CO2, N2, O2 and H2O over two carbon honeycomb monoliths with different textural development has been measured in a pressure and temperature range of interest for post-combustion CO2 capture: between 0 °C and 70 °C and up to 120 kPa for CO2, N2, and O2, and between 30 °C and 70 °C up to the corresponding saturation pressure for H2O. The maximum adsorption capacity and isosteric heat of adsorption follows the order: H2O > CO2 > N2 ≈ O2. The carbon monoliths present equilibrium selectivity towards CO2 and H2O over N2 and O2 at typical flue gas conditions. Moderate activation is preferred to maximize the CO2 adsorption capacity and selectivity in these conditions. The Toth model was employed to fit the equilibrium data for the adsorption of CO2, N2, and O2 with highly satisfactory results. The adsorption isotherms of H2O presents the characteristic “s” shape of hydrophobic adsorbents, with low uptakes at low relative pressures, which will facilitate H2O desorption during cyclic operation. These were fitted using the extended CMMS model, which describes satisfactorily the experimental data in the full relative humidity range. The adsorption kinetics were preliminary evaluated by measuring the rate of mass uptake from a mixture with 10% CO2 (balance N2) at 30 °C, 50 °C and 70 °C, and the data were fitted to the linear driving force model to obtain the kinetic rate constants.Work carried out with financial support from the HiPerCap Project of the European Union 7th Framework Programme FP7 (2007-2013; Grant Agreement number: 60855). N.Q. acknowledges a fellowship from the Gobierno del Principado de Asturias (Programa Severo Ochoa).Peer reviewe

Metformin activates AMP-activated protein kinase in primary human hepatocytes by decreasing cellular energy status.

The glucose-lowering drug metformin has been shown to activate hepatic AMP-activated protein kinase (AMPK), a master kinase regulating cellular energy homeostasis. However, the underlying mechanisms remain controversial and have never been investigated in primary human hepatocytes

A dynamic simulation model of land-use, population, and rural livelihoods in the central Rift Valley of Ethiopia

The dynamic interactions between society and land resources have to be taken into account when planning and managing natural resources. A computer model, using STELLA software, was developed through active participation of purposively selected farm households from different wealth groups, age groups and gender within a rural community and some members of Kebelle council. The aim of the modeling was to study the perceived changes in land-use, population and livelihoods over the next 30 years and to improve our understanding of the interactions among them. The modeling output is characterized by rapid population growth, declining farm size and household incomes, deteriorating woody vegetation cover and worsening land degradation if current conditions remain. However, through integrated intervention strategies (including forest increase, micro-finance, family planning, health and education) the woody vegetation cover is likely to increase in the landscape, population growth is likely to slow down and households’ income is likely to improve. A validation assessment of the simulation model based on historical data on land-use and population from 1973 to 2006 showed that the model is relatively robust. We conclude that as a supporting tool, the simulation model can contribute to the decision making process

Evaluation du risque de saignement de varices œsophagiennes chez des enfants atteints de cirrhose et en attente d'une greffe de foie

Background : Les enfants atteints de cirrhose décompensée et en l’attente d’une greffe de foie sont susceptibles de développer une hémorragie digestive haute à partir de leurs varices oesophagiennes. En raison de la morbimortalité associée à cette complication, être en mesure de sélectionner les patients à risque élevé de saignement pour une ligature endoscopique prophylactique semble être un enjeu de taille. La présence de varices oesophagiennes de grade 2 et 3 ainsi que la visualisation de signes rouges sur les varices sont des facteurs de risque de saignement bien établis dans la littérature. L’implication de l’hémostase reste cependant controversée à l’heure actuelle en raison de l’état rebalancé de la coagulation au cours de la cirrhose. Une investigation complète de l’hémostase semble dès lors indispensable afin d’exclure son implication dans le risque de saignement de ces varices. In fine, un modèle prospectif du risque de saignement de varices oesophagiennes capable de standardiser leur prise en charge prophylactique serait envisageable. Matériel et méthodes : Il s’agit d’une étude prospective et observationnelle s’intéressant aux enfants atteints d’hypertension portale dans le cadre d’une cirrhose décompensée. Chaque patient a bénéficié d’une analyse de l’hypertension portale au moyen d’un bilan échographique et endoscopique ainsi que d’une étude complète de l’hémostase. Ce bilan de l’hémostase comprend non seulement la réalisation de tests conventionnels de laboratoire mais intègre aussi des analyses dynamiques de la coagulation telles que la thromboélastométrie (analyse ROTEM®), l’analyse de la fonction plaquettaire (Multiplate®) et le temps de lyse des euglobulines. L’évènement clinique à surveiller est la survenue d’un épisode d’hémorragie digestive haute sous la forme d’hématémèse ou de méléna. Le but de l’étude réside en la comparaison statistique des enfants qui ont saigné par rapport à ceux qui n’ont pas saigné afin de déceler quels sont les paramètres à l’origine d’un risque accru de saignement de varices oesophagiennes. En raison de notre faible cohorte de patients, des analyses statistiques univariées ont été réalisées à partir de tests statistiques non-paramétriques (test de Mann-Whitney et Fisher Exact test). Résultats : 20 enfants atteints de cirrhose décompensée et nécessitant une greffe hépatique ont été inclus. 6 patients ont présenté une hémorragie digestive haute lors de la période précédant la transplantation. La présence de varices oesophagiennes de grade 2 et 3 (P-value : 0.684) ainsi que la visualisation de signes rouges (P-value : 0.684) n’étaient pas statistiquement différentes entre les deux sous-groupes. Par contre, une diminution significative du taux de fibrinogène (P-value : 0.0035) et du taux de facteur V (P-value : 0.0229) ainsi qu’une réduction significative de la fonction d’agrégation plaquettaire dépendante de l’ADP (P-value : 0.0055), de l’acide arachidonique (P-value 0.0126) et de la thrombine (P-value : 0.009) étaient observées chez les sujets qui avaient saigné. Une étude dynamique de la coagulation par thromboélastométrie nous montre que le MCF (maximum de fermeté du caillot) en analyse FIBTEM (P-value : 0.0403), le CT (temps de coagulation) en analyse EXTEM (P-value : 0.0025) et le CFT (temps de formation du caillot) en analyse EXTEM (P-value : 0.0192) permettent de distinguer les sujets qui ont présenté un saignement de ceux qui n’en ont pas présenté. Conclusion : Notre étude met en évidence l’implication de l’hémostase dans le risque de saignement de varices oesophagiennes. Un taux bas de fibrinogène (< 150 mg/dl) semble être un facteur déterminant à l’origine d’une tendance hémorragique dans notre cohorte de patients atteints de cirrhose décompensée. Son implication laisse suggérer le bénéfice potentiel d’un traitement prophylactique à base de concentrés de fibrinogène chez les sujets avec un taux bas de fibrinogène. L’analyse Multiplate® ainsi que l’analyse ROTEM® (FIBTEM et EXTEM) se sont révélées également intéressantes afin d’évaluer le risque de saignement des varices oesophagiennes chez les enfants atteints de cirrhose décompensée