Flexible combined microgas turbine plants with controlled heat recovery

The subject of consideration in the article is combined microgas turbine plants (MGTP) with a controlled regeneration degree. The direction of deeper utilization of the exhaust gases heat of microgas turbine engines (MGTE) with a controlled regenerator (CR) has been chosen, turning it into work in an organic Rankine cycle (ORC) unit. A distinctive feature of combined MGTEs with CR is the ability to have four combinations on one plant scheme, depending on the degree of MGTE regeneration, which can change due to bypassing gases past the regenerator, and redistributing the total flow of the MGTE working fluid between the waste heat boiler and the ORC unit. It has been established that the maximum relative increase in efficiency, depending on the basic configuration, is 8-20 %. The use of R-123 as a working fluid of ORC units allows to maximize the specific power of combined MGTPs by 1.29...1.9 times, and the specific thermal power by 2.2-3 times, and R-718 by 2.1-2.6 and 3.1-3.3 times, respectively, depending on the basic configuration. It is shown that, from the point of view of flexibility and efficiency, it is most advisable to use combined MGTPs with interheating of MGTE gases and an ORC unit with R-718 refrigerant as the working fluid. It is noted that water for ORC microturbine units is an inconvenient substance from an operational point of view; therefore, R-123, which has a high decomposition temperature, can be recommended.