(712a) A Comprehensive Comparative Study of Solvents for the Capture of Carbon in a Coal Fired Power Plant

Authors: 
Kotecha, P., Vishwamitra Research Institute, Center for Uncertain Systems: Tools for Optimization and Management
Diwekar, U., Vishwamitra Research Institute, Center for Uncertain Systems: Tools for Optimization and Management
Bhown, A., Electric Power Research Institute


More than 40% of the worlds & United States electricity is produced from coal based power plants. These power plants have been cited to be the largest, stationary anthropogenic source of CO2 and contribute significantly to the global warming phenomenon. Moreover, these power plants are also characterized by high consumption of water and at times could be held responsible for upsetting the ecological harmony. Despite this, these power plants are inevitable as they enhance the energy security of the nation as countries with huge reserves of coal continue to rely on them to fuel their economic growth. Though there have been some alternative technologies for electricity production, the coal based power plants will continue to exist in the foreseeable future. However, it is necessary to mitigate the ill-effects of emissions of the CO2 from these power plants failing which the sustenance of the ecological system could be jeopardized. The most promising solution is to capture the CO2 emitted from these power plants with the help of a post combustion based absorption system. Among various other factors, the selection of solvent plays a crucial role in the success of this post combustion capture technology. In this work, we have built a standalone ASPEN based flowsheet of an integrated power plant i.e., a boiler, steam cycle and an absorption based post combustion carbon capture technique. One of the unique features of this model is that the absorption and stripper columns of the carbon capture system have been modeled using the state of the art rate based models and employs the RateSep & RadFrac models in the ASPEN. As rate based models have been believed to govern the absorption in a multi-component system, the results of this study are expected to match the performance of real world columns. This was followed by the selection of some commonly used solvents for the comparative study. The properties and models of these solvents were obtained from an exhaustive literature survey. Subsequently, we identified three performance criteria viz., solvent requirement, water requirement and energy requirement for the carbon capture, to compare various solvents. These performance criteria are meant to cover both the ecological and economical impacts of the carbon capture technology. In this study, we have reported the performance of the selected solvents based on the above mentioned criteria and serves as a benchmark for testing possible novel solvents. Apart from aiding in the study of the solvents, the integrated flowsheet provides an opportunity for a systematic process synthesis analysis to make these power plants more sustainable and commercially viable.

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