(376bt) Techno-Economic Analysis of Deep Eutectic Solvent Based so2-CO2 Co-Capture Process for Flue Gas

Authors: 
McGaughy, K., Ohio University
Reza, M. T., Ohio University
Over the last few decades, coal-fired power plants emission system has been upgraded in comply with baghouse, selective catalytic reducer (SCR), and flue gas desulphurization (FGD) unit to remove fine particulates (PM 2.5), NOx, and SO2, respectively. Each individual unit increase the parasitic loads (or, decrease overall efficiencies) of the coal-fired power plant. In fact, state-of-the-art wet limestone based FGD unit from CH2M reduces the overall coal-fired power plant efficiency around 2.0-2.5% depends of the throughput of the power plant. Another eminent technology is carbon capture and storage (CCS) to reduce the greenhouse gas emission from the coal-fired power plant. Unfortunately, this additional technology will further reduce the efficiency (~28% from ~34%) from the current practice. As a result, the power plant will have to consume more coal to deliver the current electricity demand. Therefore, a common solvent, which is not harmful to the environment but capture SO2 and CO2 simultaneously, is of great need to sustain the clean electricity production from coal-fired power plant.

Deep eutectic solvents (DES) are environmentally friendly and relatively less expansive solvent than ionic liquids and amine-based solvents. DESs are eutectic mixtures of salts or complexing agents with a certain stoichiometric ratio. Wide range of metal salts, metal oxides, and hydrogen-bond donors (HBD) can be the salts or complexing agents to form DES. Despite being a relatively newer technology, the wide applications of DES including CO2 adsorption makes it very attractive separation technologies. However, the applicability of DES in CO2-SO2 co-sequestration has never been explored before.

In this project, experimentally and computationally determined parameters were evaluated and were incorporated into a full-scale techno-economic analysis for flue gas treatment. This evaluation includes several different solvents with sensitivity analysis and comparison to an NETL baseline capture process for a 550 MW coal fired power plant.