Design and Analysis of Integrated CO2 Enriched CCGT Plant Coupled with CCS

Abstract

Natural Gas Combined Cycle (NGCC) power plants are the main emitting CO2 sources in the UAE. However, the main problem with capturing CO2 from the NGCC plant is that it is highly diluted by a large amount of air used in a gas turbine; 300 to 400% of the theoretical air is required. This leads to inefficient absorption, requiring a large amount of reactive solvent to absorb CO2. In this work, we examine the potential of enriching CO2 with air in the combustion chamber in order to increase the CO2 content in the flue gas, aiming to reduce the cost of the capture plant. We develop a detailed model of the integrated system comprising of combustion chamber kinetics, CCGT plant, and MEA-based CO2 capture plant using Ansys CHEMKIN®, Aspen HYSYS v10, and Aspen Plus 10, respectively. We also performed techno-economic analyses of the integrated system to examine the viability of the system considering varying enrichment rates. The study results show a slight reduction in NGCC power output and a decrease in the reboiler duty from building a capture plant with an enriching CO2 rate. However, the economic assessment reveals that the installation of a CCP is not profitable for electricity plants with a modest production (less than 200 MW), as the whole efficiency is reduced to 10%. This is due to the increased amount of CO2 that need to be treated.