Study on power plants arrangements for integration

The three power cycles viz. gas cycle (Brayton cycle), steam cycle (Rankine cycle) and organic Rankine cycle (ORC) are arranged in two possible methods to form a triple cycle and to increase its power generating performance. In one approach, all the three cycles are arranged in series, the heat rejection of gas cycle is supplied to steam power plant having back pressure turbine and the heat rejection of steam plant is supplied to ORC plant similar to a cascading. In second option, the two bottoming cycles i.e. steam plant and ORC plant are arranged in parallel to gas turbine exhaust. In this connection, steam cycle works with high temperature heat recovery and ORC plant with low temperature heat recovery. Thermal efficiency and specific work of two triple cycles are compared with combined cycle (CC) power plant to draw the relative merits of two choices with a focus on compressor pressure ratio and gas turbine inlet temperature (GTIT). The results showed that the parallel arrangement in triple cycle offers greater benefit over the series arrangement. Therefore the wok is focused on parallel configuration triple cycle results.