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tag Performance improvement of distributed combined cycle plants through modification of structure
Jacek Kalina
Session: Poster session & Welcome drinks
Session starts: Wednesday 13 September, 17:30

Jacek Kalina (Silesian University of Technology)

Current trends in design of combined cycle power only and cogeneration plants show that developers increase plant size and complexity of the system in order to reach high power generation efficiency at acceptable specific investment cost. On the other hand national energy systems face challenges related to the use of energy from intermittent renewable energy sources. Flexibility of the system is becoming an important issue and criterion for design of energy conversion plants. In this context the distributed small and medium scale modular combined cycle plants can be an interesting alternative. Traditional combined cycle power plant consists of an industrial gas turbine, a heat recovery steam generator and a steam turbine cycle. In the case of small and medium scale plants the power generation efficiency is within the range of 42 – 47%. If supplementary firing of natural gas is applied for higher power output the efficiency is even lower. Some authors proposed bottoming of the traditional combined cycle plants with additional ORC modules. In this paper possible modifications of an entire plant structure are examined. The concept is based on a bigger number of power generation modules and modified configuration of the heat recovery steam generator to be used. Components such as internal combustion engines, turboexpanders, inverted Bryton cycle and ORC are taken into account. There are also being considered different types of gas turbines such as aeroderivative, recuperated and reheated ones. Simulations were performed using Engineering Equation Solver and Ebsilon Professional software packages. Results show that there is a room for both efficiency and flexibility improvements. Organic Rankine Cycle with relatively high working fluid evaporation temperature can play an important role in these new combined cycle plant configurations.