(471b) Design of a 400 MW Carbon-Neutral, Coal-Fired Power Plant with Integration of Waste Heat and Solar Energy

Coal-fired power plants (CPP) consumes on an average of 221 tons h^-1 of coal to generate 400 MW of electricity. The rate of emission of CO₂ from the state-of-the-art CPP operating at 60% efficiency is approximately 600 kg MW-h^-1, which is equivalent to 1.5 kmol s^-1. The amine-based scrubbers are known to effectively separate CO₂ from the flue gases which typically contains 12-15% CO₂. The captured CO₂ is then released using a regeneration process requiring an additional power of ~350 MW, which is typically supplemented by either burning natural gas or integrating with waste heat of ~250 MW from the CPP. Here we are proposing an electrochemical technique that directly coverts CO₂ absorbed in an amine-based solvent and water to either CO or HCOOH. This technique bypasses the need for regeneration process for amine-based solvent that saves ~350 MW of power, which can be used to conduct electrochemical reduction of CO₂. We found that continuous production of CO and HCOOH require lesser power as compared to other alcohols and hydrocarbons. For example, the minimum power required to produce either CO or HCOOH is ~585 MW (~380 MW is a thermodynamic limit) for 100% CO₂ Utilization Efficiency and Potential. The excess energy required for electrochemical conversion of CO₂ may be derived from the solar energy which requires a land area of 1.67 km² (38% of CPP land area), assuming a 20% effective efficiency of solar cells. Therefore, it seems plausible to support the energy requirement for electrochemical reduction of CO₂ using an integrated waste heat and solar energy management. The target performance of such system is ~1 A cm^-2 of current density at ~2 V of cell voltage. Achieving such targets require development of a high surface area catalysts operating at total overpotential of <670 mV. This results in a carbon-neutral model that can be used as a basis for designing and adapting current and new conventional thermal power plants.