Modélisation du captage post-combustion du CO2 avec évaluation de la dégradation des solvants

in Récents Progrès en Génie des Procédés (2013), 104

Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy ... [more ▼]

Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy demand. CO2 is chemically absorbed in an amine solvent that can be regenerated at higher temperature, producing a pure CO2 stream. However, the large impact of this technology on the power plant efficiency and the environmental penalty are the main drawbacks for large-scale implementation. In this work, an innovative approach combining process modeling and evaluation of the environmental penalty due to amine degradation is presented. Based on experimental results, the kinetics of solvent oxidative and thermal degradation is estimated and included in the process model developed in Aspen Plus. Using this model, the influence of operating parameters like the oxygen concentration in the flue gas or the solvent regeneration pressure is studied. This model is a first step for a multi-objective optimization of the CO2 capture process, assessing both energy and environmental penalties of this technology. [less ▲]

Effets de la pression partielle en hydrogène sur la production anaérobie de bioH2 par une bactérie chimiotrophe du genre Clostridium dans un nouveau réacteur à cylindre horizontal rotatif.

in Récents Progrès en Génie des Procédés (2011, December), 101

Hydrogen is widely considered as the most promising energetic carrier. At an industrial scale, steam reforming of methane is currently the major hydrogen producing process. But it may also be produced ... [more ▼]

Hydrogen is widely considered as the most promising energetic carrier. At an industrial scale, steam reforming of methane is currently the major hydrogen producing process. But it may also be produced from renewable biomass. Indeed, the fermentative production of hydrogen from renewable biomass using anaerobic bacteria could at least partially reduce our dependence on fossil fuel, decrease the carbon dioxide emissions and produce “green” energy. It offers the potential production of usable hydrogen from a variety of renewable resources such as carbohydrates wastes from agriculture or agro-food industries. This technology is based on anaerobic fermentation, called dark fermentation, by chemotrophic bacteria. The investigations carried out at CWBI involve selection and characterization of bacteria strains able to produce biohydrogen efficiently and with a wide range of substrate. The selected strains at the laboratory has been characterised as Clostridium sp. In order to produce hydrogen at high yields and production rates, the biotechnological process needs to be further optimized and efficient bioreactors must be designed. At CWBI, a new reactor called “horizontal rotating cylinder bioreactor” allows the production of biohydrogen from glucose with our Clostridium sp. strain with a high yield and production rate. This reactor, working continuously, has an internal volume of 2.3l but a working volume (liquid phase) of 300ml. Firstly, it enhances the hydrogen production rate by partially fixing the bacteria on the porous cylinder and thus increasing the cell concentration in the bioreactor. Secondly, the rotative cylinder enables efficient gas transfer (mainly hydrogen) from the liquid phase where it is produced by the bacteria. This is an important way to enhance hydrogen production yield by allowing the bacteria metabolism to shift in a fermentation type that produces more hydrogen. This was confirmed by increasing or decreasing the total pressure in the bioreactor and observing the influence of hydrogen production. The liquid to gas hydrogen transfer is possibly an important factor to enhance the biogas production. Our investigation confirmed this by testing different liquid to gas transfer condition in BHP test (batch fermentation in 250ml serum bottles).This was made either by decreasing total and partial pressure or by increasing the mixing state of the media. Our work concludes the importance of providing good liquid to gas transfers in the biohydrogen producing reactors to enhance the hydrogen production and reach higher yields and production rates. [less ▲]

Optimisation du procédé de captage de CO2 dans des solvants aminés

in Récents Progrès en Génie des Procédés (2011), 101

Post-combustion carbon capture in amine solvents is currently one of the most promising technologies to prevent large quantities of CO2 from being emitted into the atmosphere. Two models (equilibrium and ... [more ▼]

Post-combustion carbon capture in amine solvents is currently one of the most promising technologies to prevent large quantities of CO2 from being emitted into the atmosphere. Two models (equilibrium and kinetics) have been built using the Aspen Plus software in order to optimise the capture process. A sensitivity study at constant CO2 capture rate has shown that the solvent concentration, its flow rate and its regenerating pressure have the largest influence on the process energy requirement. Different process flowsheet modifications such as the lean vapor compression, an absorber inter-cooling and the split-flow configuration have been simulated as well, decreasing the energy cost of the process. Tests on a pilot installation will be made that will help to validate this model. [less ▲]

Taking into account cell membrane permeability to account for the response of GFP microbial biosensors : integrating the secretome in the scaling-up procedures

in Récents Progrès en Génie des Procédés (2011), 101

Strategies of improving the production of 6-amyl-1 α-pyrone obtained 2 with Trichoderma spp. through the bioreactor structure and substrate

in Récents Progrès en Génie des Procédés (2011), 101