Study on the Comprehensive Performance of Natural Gas Combined Cycle Plant Integrated With Carbon Capture System

Abstract

Natural gas combined cycle (NGCC) has the characteristics of clean, high efficiency and strong variable load capacity under certain load range. The integration of NGCC unit with carbon capture system is an important way to achieve carbon emission reduction. A 884 MW natural gas combined cycle which consists of two gas turbines, each of which is equipped with a heat recovery steam generator in International Energy Agency (IEA) report was taken as the reference system, and the system was modeled and verified by Ebsilon software. Based on the principle of energy cascade utilization, the following four different integration schemes of NGCC unit with carbon capture system were proposed. Steam extraction from the IP/LP crossover and the condensate is returned to the deaerator, steam extraction from the IP/LP crossover and the condensate after heat exchange is returned to the deaerator, steam extraction from the IP/LP crossover and the condensate is returned to the condenser, steam extraction from the IP/LP crossover and addition of a new turbine while the condensate after heat exchange is returned to the deaerator. The thermodynamic performance of four different integration schemes is further analyzed, and the energy penalty is 6.67%, 6.59%, 6.81% and 5.46%, respectively. It can be seen that the proposed scheme 4 can effectively reduce the energy penalty.

Keywords

• natural gas combined cycle (ngcc)
• carbon capture
• energy penalty