GT36
The takeover of Alstom by GE has spurred an interesting development in gas turbine OEMs: Backed by Chinese investment and orders, Ansaldo Energia is seeking out a role in the big league of gas turbine manufacturers. It has opened a gas turbine manufacturing facility in Genoa recently that would include the assembling of the new GT36 gas turbine — sequential combustion system’s H-class.
Earlier this year, Ansaldo announced the validation of the GT36. It reported that test results showed a power output above 340 MW at 41% efficiency. In combined cycle this corresponds to performance exceeding 500 MW at 61.3% net efficiency in ISO conditions and 720 MW at 61.5% efficiency for the GT36-S5 (the 50Hz scaled version).
As mandated by the European Commission, the gas turbine division of Alstom, including the then under-development GT36 project, was hived off and sold to Ansaldo Energia that had only the Siemens-derived V machine in its kitty then. In 2014, Shanghai Electric acquired a 40% stake by paying 400 million euros to Fondo Strategico Italiano, Italy’s state-backed investment fund, which held 85% in the turbine manufacturer.
The following year, the Ansaldo, Alstom GT deal was finalized. In 2016, Ansaldo bagged eight new orders for the GT26. Ivan Rice, writing in turbomachinerymag.com, noted perceptively that on the technical front this signaled the continued existence and development of the sequential combustion system, or the reheat concept applied to gas turbine combustors. This technology boosts gas turbine flexibility and a unique ability to achieve environment compliance and efficiency at very low loads — otherwise called turndown performance.
Sequential combustion in can
The new GT36 gas turbine, the first of which has been operating at Birr since May 2016, the sequential combustion concept is featured in can combustors. In the GT26, the concept was implemented through two annular combustors called the EV and the SEV. A single-stage HP turbine comes in between the two combustors.
GT36’s 60 Hz version uses 12 cans, while the 50 Hz version employs 16 cans, and the HP stage in between the annular combustors in GT26 is eliminated. The compressor stages have also been reduced from 22 in GT26 to 15.
The GT36 also features the FlameSheet combustor technology developed by third-party aftermarket supplier Power Systems Manufacturing, based on Florida. PSM, which had been acquired by Alstom, came to Ansaldo Energia as part of the deal. The PSM FlameSheet was originally a retrofit for GE’s F-class gas turbines.
The Dilution Air Mixer is a multi-row jet mixer with protruding air nozzles. The sequential burner liner uses features from PSM’s transition piece product too. The GT36 gas turbine can switch between two operational modes, Performance Optimized Mode, and XL (eXtended Lifetime) Mode (a feature that is also available for GT26 gas turbines). The Performance Optimized Mode targets performance and output while XL allows extension of service intervals.
Stronger cooperation
On June 16, at the Ansaldo Foundation in Genoa, three important cooperation agreements were signed on one side by Ansaldo Energia and Shanghai Electric Group (which holds a 40% stake in Ansaldo Energia), and on the other by Chinese electric companies Shenergy Electric Group and Shanghai Electric Power.
The first two industrial cooperation agreements cover the construction of two power generation plants in the Shanghai area using GT36. The third “One Belt & One Road” strategic cooperation agreement has the aim of developing a project in Pakistan, in which Shanghai Electric Power is an investor, and Shanghai Electric together with Ansaldo Energia is the supplier of the machinery and main components for the plant.
