Methods for efficiency improvement of the semi-closed oxy-fuel combustion combined cycle

Abstract

The paper presents thermal schemes of the semi-closed oxy-fuel combustion combined cycle with preliminary cooling of the coolant flow. The first scheme involves the coolant flow preliminary cooling in a surface heat exchanger. The heated agent is a part of condensate taken from the steam turbine circuit. The net efficiency improvement against the base cycle is 3.2% for the working fluid initial temperature of 1700°C. The coolant flow temperature is reduced down to 150°C. The second scheme involves injection of the water taken from the cooler-separator. In this case the power facility net efficiency improvement may be up to 1.5%.