![]() Likewise, fine/ultrafine powders have also been proposed as a possible solution to overcome the drawbacks of the calcium looping (CaL) process, which can be carried out for both CCS and TCES-CSP applications, according to the following reaction scheme: Besides that, it must be considered that most of the sorbents commercially available are produced in a fine powdered form. As a matter of fact, due to their distinctive properties, size, and nature their surface chemistry and porous structure can be easily adjusted/functionalized at the molecular level, i.e., by introducing chemical groups/ligands with basic functionalities (e.g., carbonates, amino groups, etc.) able to tailor their adsorption behavior towards the CO 2 molecules. ![]() Indeed, they can quite easily serve as the substrate for the production of ad-hoc synthesized sorbents, i.e., characterized by remarkable affinity towards the molecules of CO 2. In the framework of the need to produce specific adsorbent materials, fine/ultrafine particles have attracted growing interest in research. Indeed, a good sorbent should be relatively convenient from the economic point of view, but, at the same time, it should be able to provide good performances at low CO 2 pressure (<0.2 atm ): high equilibrium adsorption capacity, fast kinetics of adsorption/desorption, stability to cyclic operations and tolerance to water vapor and other possible impurities in the exhaust stream. However, the selection of the sorbent is crucial for adsorption to become a competitive solution. In this framework, TSA combined with an indirect heating process (for example by means of heat exchanger tubes), is considered to be very promising for post-combustion operations. In particular, regarding the critical issue of the sorbent regeneration, different strategies can be adopted, acting either on the pressure (PSA-pressure swing adsorption) or on the temperature (TSA-temperature swing adsorption) of the system to induce the desorption of the CO 2 molecules. Therefore, adsorption has been proposed as one of the most attractive and promising alternatives, being characterized by relatively low energy consumption for the sorbent regeneration, high selectivity, no liquid waste streams, and quite a wide range of possible operating temperatures. Among these, amine-based absorption, even though being the most mature technological option, is characterized by several shortcomings, when applied for post-combustion capture: huge energy demand for the regeneration of the sorbent, thermal/chemical degradation of the amines, amine losses due to evaporation and corrosion problems. In regards to the CCS, different separation techniques are available to separate the CO 2 from the combustion flue gases: absorption, adsorption, cryogenics separation, membranes, etc. Likewise, fine/ultrafine particles have also found application in the Carbon Capture and Storage (CCS) sector, for the reduction of the CO 2 emissions to the atmosphere, and in the thermochemical energy storage (TCES) in concentrated solar power (CSP) plants. įor instance, nanostructured catalysts, characterized by a hierarchical porosity, have been synthesized in the framework of different chemical processes, such as combustion and gasification and fuel and polymer production. In fact, due to their exceptional properties, mainly derived from their characteristic dimensions and large surface area per unit mass (which means that they are able to offer larger contact/reaction efficiency), they can be applied in a variety of industrial sectors, such as in the production of foods, plastics, cosmetics, catalysts, and metallurgic components. More specifically, the role played by the acoustic perturbation and its effect on the fluid dynamics of the system and on the performances/outcomes of the specific chemical processes are pointed out.įine and ultra-fine powders, i.e., characterized by particle size lower than 30 μm, have been characterized by increased research interest in recent years. The present manuscript reviews the main results obtained so far using the SAFB. In this context, the sound-assisted fluidized bed reactor (SAFB) designed and set-up in Naples represents a useful device to study the behavior of cohesive powders also in the framework of low and high temperature chemical processes, such as CO 2 adsorption and Ca-looping. Therefore, developing of technologies able to handle/process big amounts of these materials is of great importance. For example, they are considered in the framework of the Carbon Capture and Storage (CCS), for the reduction of the carbon dioxide emissions to the atmosphere, and in the framework of the thermochemical energy storage (TCES) in concentrated solar power (CSP) plants. Fine/ultra-fine cohesive powders find application in different industrial and chemical sectors. ![]()
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