Development of Supercritical Organic Rankine Cycle Turbine for Waste Heat Power Generation

In this study, a turbine applicable to a supercritical ORC power generation system with higher power generation efficiency than the typical ORC power generation system was developed. This paper describes the turbine design, fabrication and performance tests for developing a 100kW class power generation turbine. R-1234ze(E) was selected as the working fluid in consideration of Global Warming Potential. The overall turbine expansion ratio was 9, and the turbine consisted of a two-stage centrifugal turbine. The magnetic bearings were installed, and the turbine and generator were assembled into a single casing. The rotation speed was selected as 36,000rpm through the specific speed and the specific diameter analysis. Based on these analysis results, one-dimensional design, three-dimensional shape design, and three-dimensional performance analysis were conducted. Turbine components were fabricated based on CAD drawings and three-dimensional modeling. The assembled turbine was installed in a supercritical ORC power generation system. The cooling tubes were additionally installed to maintain a stable temperature inside the turbine. Through the performance test, it was confirmed that the developed turbine generated electric power of 100kW. In this paper, important matters to be considered when developing turbines for supercritical ORC power generation system were specifically mentioned.