Natural Gas Combined Cycle Power Plant Integrated to Capture Plant

Abstract

A natural gas combined cycle (NGCC) power plant with capacity of about 430 MW integrated to a chemical solvent absorber/stripping capture plant is investigated. The capture ratio is 90%, and the captured CO2 is compressed to 75 bar, liquefied, and finally pumped up to 110 bar. Both full load and partial load conditions are studied. The energy penalty for CO2 capture is 398.4 kWhel/ton of CO2, which causes a 7.5%-points reduction in the power plant net efficiency. From this energy penalty, 4.6%-points is related to the steam extraction and 2.9%-points is related to electricity consumption. The integration of the power plant with the compression section of the capture plant for preheating the water to the heat recovery steam generator (HRSG) will not improve the net plant efficiency. From the partial load investigation, the net efficiency of the variable IGVs gas turbine is shown to be about 6.2%-points higher than the efficiency of the constant IGVs gas turbine at 50% load. Also, the power plant with the throttled valve configuration for steam extraction has a better performance than the sliding configuration steam extraction.