LE CAPTAGE DU CO2 DANS LES CENTRALES THERMIQUES

This review is devoted to assess and compare various processes aiming at recover CO2 from power plants fed with natural gas (NGCC) and pulverized coal (PC). These processes are post combustion CO2 capture using chemical solvents, natural gas reforming for pre-combustion capture and oxy-fuel combustion with cryogenic recovery of CO2. These processes were evaluated to give some clues for choosing the best option for each type of power plant. The comparison of these various concepts suggests that, in the short and medium term, chemical absorption is the most interesting process for NGCC power plants. For CP power plants, oxy-combustion can be a very interesting option, as well as post-combustion capture by chemical solvents

CO capture study in advanced Integrated Gasification Combined Cycle

International audienc

CO2 capture processes in power plants - Le captage du CO2 dans les centrales thermiques

This review is devoted to assess and compare various processes aiming at recover CO2 from power plants fed with natural gas (NGCC) and pulverized coal (PC). These processes are post combustion CO2 capture using chemical solvents, natural gas reforming for pre-combustion capture and oxy-fuel combustion with cryogenic recovery of CO2. These processes were evaluated to give some clues for choosing the best option for each type of power plant. The comparison of these various concepts suggests that, in the short and medium term, chemical absorption is the most interesting process for NGCC power plants. For CP power plants, oxy-combustion can be a very interesting option, as well as post-combustion capture by chemical solvents.Comment: PDF file available for free at http://pubs.ub.ro/?pg=revues\&rev=cscc6\&num=201011\&vol=1\&aid=297

How to improve the public perception of hydrogen?

International audienceMost of countries which promote research and development programs on hydrogen energy have considered the public acceptance. In the open literature, results of some opinion polls are available, which have been performed in USA, Canada, Japan, Germany, Island.... In order to provide a first basis to the AIDHY project, (the objective of which is to improve the public acceptance of hydrogen as an energy vector and is supported by the French Agence Nationale de la Recherche), the AFH2 (Association Française de l'Hydrogène) has realized two opinion polls, during year 2008. The first one, during the fair of Transports and sustainable mobility, during September, in the gardens of Trocadéro and the second, on the occasion of the exhibition for equipment, technologies and services of environment (Pollutec), in Lyon, during December. We will provide the notable results of these two polls. We will present a synthesis of opinion polls in various countries and briefly point out, the initiating circumstances, methodologies, classes of public... Finally, we will examine how the information given to several categories of people, can influence the perception of problems linked to hydrogen energy and provide a few recommendations in order to improve the public acceptance of hydrogen

Kinetics of Carbon Dioxide Absorption into Aqueous Solution of a Polyamine

Published in an open access journal this article is also available online at http://www.chemicalbulletin.ro/admin/articole/54742art_1(1-4).pdfInternational audienceThe absorption of CO2 into an aqueous solution with 1.45 mol/L 1, 5, 8, 12- tetraazadodecane (APEDA) polyamine has been studied at three temperature (298, 313, 333 K) in a Lewis type absorber with a constant gas- liquid interface area of (15.34 ± 0.05) x 10-4 m2. The experimental results have been interpreted using the equations derived from the two film model with the assumption that the absorption occurred in the fast pseudo- first- order kinetic regime. The results confirmed the validity of this assumption for the experimental conditions: the enhancement factor was always greater than 3. The rate constant derived from the experimental data (kov, s-1) was correlated through the Arrhenius plot (ln kov = A- B/T), and the optimal values of the constants A and B were obtained by the linear regression. The absorption of CO2 from flue gas into APEDA solution is a promising process for practical application at least from the kinetic point of view. The rate constant derived from experiments is of the same order of magnitude as that for the absorption into 2- amino- 2- methyl- 1- propanol (AMP) activated with piperazine (PZ) which was found to be the most advanced system among the published data up to now

Production of Synthetic Gasoline and Diesel Fuel from Dry Reforming of Methane

AbstractThe dry reforming of methane produces synthesis gas from carbon dioxide and methane (CH4). Although this concept has many environmental and economic incentives, today it is not implemented in large plants. The purpose of this study is to illustrate the potential of dry reforming of methane for industrial applications by producing synthetic fuel from the combination of dry and steam reforming of methane. The proposed process includes four main units: production of synthesis gas from the dry and the steam reforming of methane, Fischer Tropsch synthesis, waxes hydro-cracking Fischer Tropsch waxes, product upgrading and hydrogen recovery. Simulation model of this process is carried out with Aspen Plus® software (Advanced System for Process Engineering) which allows us to define and analyze the optimum conditions and equipment specifications for each unit. Energy consumption and CO2 balance of this process are also calculated. The main interest of our proposed process is its very favorable carbon balance

Assessment of the Flue Gas Recycle Strategies on Oxy-Coal Power Plants using an Exergy-based Methodology

A presentation of this paper was given at the 16th Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction, Rodes(Greece) 29 September- 2 October 2013This article is available online at http://www.aidic.it/cet/13/35/057.pdfInternational audienceWhile oxy-combustion CO2 capture was foreseen to have higher improvement potential than post-combustion a decade ago, research has not been carried out at the same pace since then and today, the latter exhibits higher technological maturity along with low energy penalty thanks to advanced process integration and solvents formulation. Thus, significant efficiency improvement is needed for the oxy-combustion route to be competitive with post-combustion for carbon capture on coal-fired power plants. In order to achieve such improvements, process integration at system level is required to assess the true energy savings potential of oxy-combustion. In this study, an exergy-based methodology is performed to compare various flue gas recirculation strategies on a state-of-the-art 1100 MWe gross oxy-fired power plant. Exergy analysis at unit operation level allows the identification of the location and the magnitude of the thermodynamic irreversibilities occurring in the process, leading to an enhanced understanding of the studied system. In addition to the reference case in which the secondary recycle is fully depolluted and dehydrated; three alternative flue gas recirculation options have been investigated. Among the studied strategies, recirculation of the secondary flow prior the regenerative heat exchanger with a high temperature particle removal device leads to the highest net plant efficiency. This option not only allows the minimal exergy losses in the boiler but also minimizes the flowrate going through the downstream depollution devices. The net plant efficiency obtained for this architecture is 38.0%LHV, which represents a 3% increase compared to the reference oxy-combustion plant. Comparing this figure to an air-fired power plant modeled with the same set of hypotheses, the energy penalty is 8.1%-pts

Towards Second Generation Oxy-pulverized Coal Power Plants: Energy Penalty Reduction Potential of Pressurized Oxy-combustion Systems

AbstractDuring the last decade, CO2 capture on coal power plants has been the subject of sustained attention as one of the most credible way to drastically reduce anthropogenic greenhouse gas emissions. Significant reduction in the energy penalty related to the oxy- combustion routes has been achieved but uncertainties remain in the operation of such a process inducing major modifications of the power island. In this context, for oxy-combustion, and more generally carbon capture to become a reality, its energy penalty shall be drastically reduced. In that perspective, cutting edge strategies allowing taking full advantage of oxy-fired operation have to be investigated. Among them, boiler pressurization has been identified as one of the most promising solution. Two major pressurized oxy-combustion concepts have emerged in literature: the flameless combustion technology (ISOTHERM®) and the staged-pressurized oxy-combustion (SPOC) concept. According to the authors describing those two processes, whilst very different in the combustion temperature control strategy, they both succeed in allowing pressurized operation.In this work, those two concepts have been compared to an air-fired, a conservative and optimized atmospheric oxy-fired power plants in terms of energy performances. The reason underlying below the observed differences, have been determined using exergy analysis. The SPOC process leads to significantly lower energy penalty, as low as 3.8%-pts compared to the ISOTHERM® concepts which lead to performance in the same order of magnitude than the optimized atmospheric design. It has been highlighted that this difference is essentially due to the large flue gas recycling requirement for the latter concept to control combustion temperature

Procédé de fabrication de Gaz Naturel de Synthèse par couplage d'une méthanation avec une électrolyse de vapeur d'eau à haute température

National audienceLe procédé présenté ici est un procédé de type Power-to-Gas dont l'objectif est de produire un gaz de synthèse injectable sur les réseaux de gaz naturel, en couplant une électrolyse de vapeur d'eau à haute température à cellule à oxyde solide (Solid Oxide Electrolysis Cell) et une hydrogénation de CO2 afin de produire du méthane, composant majeur du gaz naturel de synthèse. La simulation de ce procédé est réalisée avec le logiciel de simulation ProSim Plus 3® et des modèles spécifiquement développés pour l'électrolyseur à haute température d'une part et pour le réacteur de méthanation d'autre part ont été mis en place. Ces modèles permettent également l'évaluation économique puisque le calcul d'un paramètre de dimensionnement de ces réacteurs est intégré. La simulation, lors de la génération du gaz de synthèse, montre un rendement énergétique élevé (79,2%), supérieur au rendement des filières à basse température. Le procédé développé pour le stockage est également utilisable pour régénérer de l'électricité par réaction électrochimique à partir de gaz naturel

Le goitre plongeant à Tlemcen dans l’ouest algérien: aspect clinique et thérapeutique de 1996-2014

La définition du goitre plongeant, la plus couramment employée, est tout goitre ne siégeant pas dans la région cervicale en position opératoire. Le but d'évaluer sa prise en charge, en insistant plus particulièrement sur les examens préopératoires, les difficultés chirurgicales et les complications postopératoire. Etude rétrospective étalée sur 16 ans; portant sur 50 cas colligés au service de chirurgie viscérale du CHU Tlemcen. L'intervention a consisté en une thyroïdectomie totale par voie cervicale dans 94% des cas. Ont été notées essentiellement, les hématomes, des paralysies récurentiels et les hypoparathyroïdie. L'âge moyen est de 54,76 ±11,992 ans Le caractère plongeant du goitre à été retrouvé chez 52% (n=26) parune échographie thyroïdienne. Le scanner cervico-thoracique était pratiqué chez 25 patients 50%. Il a permis de confirmer le caractère plongeant du goitre. Tous nos patients ont bénéficié eu un geste radicale (thyroïdectomie totale n=45, 90%), alors que 5 patients (10%) ayant déjà ont eu un geste sur la thyroïde, ont subi une totalisation. L'examen histologique à confirmé la bénignité dans 48 cas 96 %. Trois patients (6 %) avaientune paralysie récurentielle transitoire et un cas (2%) de paralysie récurentielle persistante. L'hypoparathyroïdie transitoire était notée chez (14%). Les goitres plongeants représentent une éventualité assez fréquente. Souvent révélés à l'occasion d'un examen clinique. L'examen tomodensitométrique qui permet l'exploration des espaces peu accessibles à l'imagerie conventionnelle. L'imagerie par résonance magnétique nucléaire paraît constituer une technique d'avenir.Keywords: Goitre plongeant, région cervicale, ouest algérien