Executive Summary : | Global awareness about CO₂ emissions has increased during the last decades, leading to significant attention on the post-combustion CO₂ capture technology because of its potential to reduce CO₂ emission without drastically changing the dependence on the existing power plants/industries. Out of all post-combustion CO₂ capture technology, chemical absorption especially amine-based solvents are the most matured available technology. Conventional aqueous monoethanolamine (MEA) based CO₂ absorption process has major drawback in terms of solvent degradation, solvent loss, high corrosiveness and high regeneration energy. Therefore, there is a need for research on alternative solvents and also process modification in order to reduce the operating and capital cost. A new bi-phasic solvents is an upcoming new technology and has received lot of attention during last 4-5 years. Typically, amine group is divided into three categories: primary, secondary and tertiary. The primary and secondary amines require more regeneration energy to compared to tertiary amines. However, whereas the heat of absorption and reaction rate are high in the case of primary and secondary amines, the tertiary amines have a lower heat of absorption and a slower reaction rate. Therefore, a tertiary amine or amine blend with a high absorption rate and a low heat of reaction could reduce the regeneration energy. As a result, blends containing tertiary amines have been widely investigated. The mixture of primary-tertiary amine or secondary- tertiary amine forms two immsible liquid phases upon CO₂ loading. By separating out the CO₂ rich phase, it is possible to send a smaller volume of solvent for regeneration, thereby, potentially reducing the process energy demand for regeneration. However, the most challenging is the identification of the suitable bi-phasic solvents for the best performance of the absorber and also desorber. This is the scope of the proposed proposal. In this proposed project, two bi-phasic solvents will be studied under both absorption and desorption condition. The CO₂ absorption capacity and cyclic capacity of the bi-phasic solvent will be measured and compared with that of conventional MEA solvent. The mass transfer and heat transfer behaviour in CO₂/bi-phasic solvent will be measured at reactor scale. Based on the information gathers from the experimental investigations, a systematic CFD model will be developed which can predict hydrodynamics, adsorption and also thermodynamic parameters in CO₂ adsorption and desorption process. Process intensification options like modification of the packing material for better heat and mass transfer will also be suggested. This proposed project address process intensification of solvent-based CO₂ capture process in terms of a bi-phasic solvent blend for better CO₂ absorption and high cyclic capacity and also, new design of packing material for better gas-liquid mixing. |