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Various Applications of Ceramic Membranes
Published in Chandan Das, Sujoy Bose, Advanced Ceramic Membranes and Applications, 2017
Membrane contactors have significant advantages over conventional absorption systems. Those advantages include, among other things, better yields/selectivities (e.g., via equilibrium shift), better energy management, more compact design, extension of catalyst lifetime, etc. [10,11–13]. Those functions are schematically shown in Figure 9.2. These are nondispersive contacting arrangements in which the membranes do not offer selectivity for separation; however, as an alternative, these act as barriers to separate two phases and intensify the effective contact area for mass transfer. One of the most visible benefits of membrane contactors is their extremely high interfacial area, which can considerably cut equipment size and hence lead to process intensification [7,11,14–16]. For example, the use of gas absorption membrane (GAM) systems has been explored as an alternative to traditional packed columns [16]. A membrane gas/liquid contactor has been used for natural gas sweetening (CO2 and H2S removal), dehydration, and CO2 removal from exhaust gas. Membrane gas/liquid contactors operate with liquid on one side of a membrane and gas on the other. Here the pressure is essentially the same on both sides of the membrane and absorption into the liquid provides the driving force. The increased specific area of the membrane gas/liquid contactor allows for a 65%–75% reduction in weight and size compared to conventional towers [14].
Transient simulation of SO2 absorption into water in a bubbling reactor
Published in Journal of Environmental Science and Health, Part A, 2023
Yuyang Cai, Zhen Wang, Dunyu Liu, Jun Chen, Jing Jin, Qi Qin, Ke Liu, Haixiang Hu, Sijie Li, Huancong Shi
Bubbling reactors are an important type of gas-liquid contactor, which introduces gases into absorbing liquid to realize effective mass transfer and absorption processes during the formation and rising of bubbles.[7] The main advantages of bubbling reactors include a simple process, small capital investment,[7] and low maintenance due to no redundant moving parts.[8] In the development of efficient bubble columns, a large effective gas-liquid contact interface area and high mass transfer rate are generally required.[9] In commercial applications of bubble columns, multi-stage bubbling operation,[7] perforated multi-orifice plates,[7] and internal structure[9] have been proposed to generate high turbulence for an efficient mass transfer process.
Recent development of integrating CO2 hydrogenation into methanol with ocean thermal energy conversion (OTEC) as potential source of green energy
Published in Green Chemistry Letters and Reviews, 2023
Mohd Hizami Mohd Yusoff, Lau Kok Keong, Nor Hafizah Yasin, Mohammad Syamzari Rafeen, Amiruddin Hassan, Geetha Srinivasan, Suzana Yusup, Azmi Mohd Shariff, A. Bakar Jaafar
Efficient CO2 capture process is a substantial step prior to CO2 utilization to ensure a feasible zero carbon emission goal. In past decades, various CO2 capture technologies have been proposed to capture CO2 from post-combustion and industrial processes. These technologies include absorption, membrane separation, cryogenic separation, adsorption, and gas hydrate separation. Absorption is one of the most widely used technologies for CO2 capture as it is a well-established method, and it can recover high purity of CO2 (41–44). Research and development have been focusing on enhancing the effectiveness of the solvent used in absorption and the intensification of the gas–liquid contactor as the mass transfer is significantly influenced by diffusion rate as well as the thermodynamic capacity of the solvent. The common solvent used for CO2 absorption is the amine-based solution. Primary and secondary amines such as Monoethanolamine (MEA) and Diethanolamine (DEA) are highly reactive with CO2 and easy to be regenerated through the heating process (45,46). However, they are highly corrosive, require high regeneration energy, and has limited absorption capacity at 0.5 mol CO2/mol amine (47). Due to this, a tertiary amine which is methyldiethanolamine (MDEA) attracts the attention of researchers due to its high absorption capacity (1.0 mol CO2/mol amine) and required less regeneration energy (48,49). However, it has slower reaction kinetics and higher degradation rate as compared to primary and secondary amine (46,50,51). Another alternative solvent is the potassium carbonate (PC). It is less corrosive, non-volatile, environmental friendly and consumes less energy (52,53). The only challenge associated with PC solvent is the slow absorption rate (52,54,55). Thus, the use of rate promoters is recommended by various researchers to enhance the kinetics of PC with CO2.