Optimal design for integrating co₂ capture and fuel conversion technologies in A 500 MWE coal-based power plant

A conceptual study was conducted towards a new design for more efficient fuel conversion and CO₂ capture in a future 500 MWe power plant that incorporates both new conversion technologies to optimize plant efficiency and new carbon dioxide (CO₂) capture methods. Conventional means of power generation without CO₂ capture (e.g., air-fired pulverized coal combustion and fluidized bed combustion) formed base cases to evaluate advanced combustion technologies with CO₂ capture. The following capture schemes were investigated: 1) Pre-combustion decarbonization consisting of gasification or reforming processes with CO₂ separation membranes; 2) Denitrogenation methods such as oxycombustion and chemical looping combustion; 3) Post-combustion CO₂ recovery using solvent absorption, membrane separation and solid adsorption. Evaluations were based on: 1) Efficiency of electricity generation; 2) Fuel consumption and CO₂ emitted per unit electricity; 3) Feasibility of scaleup; and 4) Energy penalty associated with capture. Both the methods of CO₂ capture and the technology of energy conversion were found to influence the overall plant efficiency and amount of CO₂ that can be captured. Advanced combustion technologies enable the production of concentrated CO₂ emission streams, but involve complex process designs. Gasification-based processes and chemical looping combustion emerged as efficient options for future coal-based power plants. These power generation technologies were integrated with selected CO₂ capture technologies to recover a high percentage of the CO₂ produced (> 90%) while maintaining reasonable power generation efficiency (> 35%). The integrated combinations were optimized with respect to net power generation efficiency, fraction of CO₂ captured, and scale-up considerations. An optimized design balancing those parameters and scale is presented as a solution for a coal-based 500 MWe power plant.