COMBINED CYCLE GAS TURBINE (CCGT) WITH INTEGRATED ORGANIC RANKINE CYCLE (ORC) PLANT (18-Jan-2010)

RP13285

COMBINED CYCLE GAS TURBINE (CCGT) WITH INTEGRATED ORGANIC RANKINE CYCLE (ORC) PLANT

BRIEF ABSTRACT

    The present disclosure is a technique to integrate a low temperature thermal cycle such as, for example, an organic rankine cycle (ORC), into a combined cycle gas turbine (CCGT) plant. Further, the low temperature thermal cycle plant utilizes an auxiliary low-grade heat source from the combined cycle gas turbine plant to provide additional power production.

KEYWORDS

    Low temperature thermal cycle(s), organic rankine cycle, ORC, combined cycle gas turbine, CCGT, auxiliary heat source(s), low-grade heat source(s), additional power, auxiliary cooling system and auxiliary cooling loop.

DETAILED DESCRIPTION

    The combined-cycle gas turbine (CCGT) power plant consists of one or more gas turbine generators equipped with heat recovery steam generators to capture heat from the gas turbine exhaust. Use of the otherwise wasted heat in the turbine exhaust gas results in high thermal efficiency compared to other combustion based technologies. Further, the CCGT power generation is the most energy efficient and clean method of fossil fuel generation.

    However, in the CCGT system many auxiliary heat sources such as low grade heat are not used with the plant configuration. Further, a significant fraction of the condenser heat is typically not used with the existing steam

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RP13285

bottoming cycles. Currently, there exists no technique that utilizes these auxiliary heat sources in the CCGT system. Therefore, there is a need for developing a technique that enables the use of auxiliary heat sources in the systems such as CCGT.

    The present disclosure proposes a technique that enables the use of auxiliary low-grade heat sources and results in additional power production by integrating a low temperature thermal cycle such as an organic rankine cycle (ORC) system into the CCGT plant. The ORC systems have several key benefits over traditional steam turbines including lower operating temperature (down to 75 C), less wear and tear on turbines (clean single fluid environment) and no requirement to expose a heat source to the environment (no emission power generation is possible using these units in a closed geothermal system, for example).

    Figure 1 illustrates the integration of ORC into the CCGT plant in ac...