Doosan Enerbility Aims to Bring 630°C Rotor into Commercialization

On August 24th, Doosan Enerbility announced that it had succeeded in developing a 630°C rotor and was preparing to commence fabrication of the rotor so that it may soon be commercialized. The rotor is a cylinder-shaped component that functions as an axis of rotation in high-speed rotating equipment such as turbines and generators. A large-sized forged rotor usually weighs around 17.5 to 37.0 tons and has a diameter of 0.95 to 1.28 meters and a length of approximately 6.1 to 8.5 meters.  A plurality of blade foils is connected to the rotor to build a steam turbine.

The 630°C rotor-applied steam turbine is scheduled to be supplied for the first time to the Boryeong New Combined Cycle Power Plant, which Doosan had signed on to as the main components supplier this past June. A combined cycle power plant goes through the first cycle of producing energy by operating the gas turbine, which emits exhaust gas that is used to generate steam for the steam turbine, leading to the second cycle of power generation. The Boryeong New Combined Cycle Power Plant project is the first project to which the Korean-standard gas-fired combined cycle power plant is being applied.  Doosan Enerbility has the role of supplying the main components, such as gas turbines and steam turbines.

The gas turbine being supplied by Doosan to the Boryeong New Combined Cycle Power Plant is an ultra-large 380MW gas turbine. As the steam generated from the combined cycle has a notably high temperature of 620°C, if the existing rotors were to be used, the performance cannot be guaranteed as there is a risk of strength and durability issues arising. Since any attempts to cool down the steam to a temperature more suitable for the existing rotors would lead to an undermining of the power generating efficiency, the need was recognized for the development of a rotor that is operable at the high temperature of 620°C.

To this end, Doosan Enerbility embarked on development of the 630°C rotor as part of the “Technology Development for Strategic Core Materials Self-Reliance” project, a project that was jointly pursued by the Ministry of Trade, Industry and Energy(MOTIE) and Korea Evaluation Institute of Industrial Technology (KEIT) in 2020.  The development of a 630°C rotor requires the highest level of expertise in steelmaking, forging and heat treatment.  Doosan Enerbility, which has casting and forging shops at its Changwon headquarters, steadily built up its expertise over the years through direct involvement in processes ranging from the  development of materials to fabrication of power plant components that include gas turbines and steam turbines, as well as reactors and boilers.  In 2002, Doosan commenced development of the USC* technology, leading to its swift obtainment of technologies for the development and manufacturing of high-temperature, high-pressure materials. Doosan Enerbility is currently the only company in the world with the capability to manufacture high-strength, high-ductility 630°C rotors.
*USC(Ultra Supercritical) : A type of power plant that consists of a turbine with a steam pressure of 246㎏/㎠ or higher and a steam temperature of 593°C or higher. The higher the pressure and temperature of the steam, the higher the power generating efficiency, which makes this an eco-friendly high-efficiency technology that can help reduce fuel consumption.

“We find it truly meaningful to be able to contribute to the power generating efficiency of the first Korean-standard gas-fired combined cycle power plant project, which has Doosan’s 630°C rotor applied,” said Yongjin Song, CSO of Doosan Enerbility.  “Backed by the pride we have in holding the capability to develop and manufacture world-class materials, we plan to continue with our efforts to develop competitive products in the future.”