Kawasaki Completes “Flagship” Gas Turbine
Company’s highest power output to meet anticipated worldwide increase in power generation needs
Kawasaki Heavy Industries (KHI) has completed the development of a new 30 MW gas turbine called the L30A and recently launched it into markets worldwide.
Labeled by KHI as the flagship of its portfolio of gas turbines, the company said that not only does the L30A have the highest power output power in the company’s product lineup, its thermal efficiency is the same or higher even though the L30A has a heavy-duty structure.
At ISO conditions, the L30A has 30.9 MW of rated output, 41.3% of thermal efficiency and 470°C of exhaust temperature, which KHI claimed makes the L30A engine more effective for co-generation and combined heat and power plant (CHP) applications.
The L30A is a twin-shaft machine and has a 14-stage axial flow compressor, eight-can combustors and a horizontally split casing for a gas generator module as a basic structure from the well-proven Kawasaki M7A and L20A series, the company said. For the L30A, KHI adopted the same configuration as its 1 MW class twin-shaft gas turbine, the M1F and 2.5 MW class Super Marine Gas Turbine (SMGT) research engine. In addition, KHI said the L30 was designed as an “easy-maintenance” engine on-site: for example, with multi Bore Scope Inspection (BSI) ports on the engine casing.
The newly developed 14-stage compressor has a pressure ratio of 24.5 with rated air flow of 86.5 kg/s. KHI’s proven Dry Low Emission (DLE) technologies are adopted to its combustor design, and NOx emission of 15 ppm (15% = O2) has been achieved.
KHI added that a newly designed two-stage gas generator turbine employs the company’s cooling design using conjugate heat transfer and flow analysis. A three-stage power turbine (PT) has the interlocking tip shroud type, which the company said reduces vibration level for wider operating range with lower pressure losses.
The adopted horizontal split casing structure enables the dismounting of hot parts including combustors, GGT blades and vanes for inspection or replacing on-site, said KHI.
During engine tests, the gas generator turbine blades’ temperatures were measured. KHI said all the stages of turbine blades and the first and third stage blades of the power turbine were measured and confirmed to be below the temperature criteria. During the testing, GGT first turbine blades’ temperature distribution was also measured with this system.
The measured results correspond to the calculated distribution of CHT flow analysis and were confirmed below the criteria, although KHI said there is a slight discrepancy in the temperature distribution. Power turbine vibrations were measured by using a telemetry system and were confirmed to be below the high-cycle fatigue limit, the company said.
The L30A DLE combustor consists of three burners — the pilot, main and supplemental burners. In DLE mode, the fuel for the pilot burner is shut down except for a small amount of fuel for maintaining minimum (torch) flame. As the load increases, the fuel distribution of the supplemental burner will be increased in order to keep lower NOx emission levels.
The DLE combustor engine test has been conducted and NOx emissions were confirmed to be less than the target value of 15 ppm from 50 to 100% of load range, the company said.
An application study of the L30A for a CHP system was carried out with typical inlet and outlet pressure losses. The L30A could produce 28.4 MW of electric power and 46.2 tonnes/hr of saturated steam. Total efficiency was 83.1%, verifying to KHI that the L30 CHP application “would be a very effective solution for maximum energy utilization.”
The first commercial L30 CHP plant will be for a Japanese chemical company and its construction work started in July 2011. This plant will be in commercial operation beginning October 2012.
KHI’s first industrial gas turbine was introduced in 1974 for standby use, and its base-load model was launched in 1984. Since then, KHI has been developing and supplying both standby and base-load models to customers in the 150 kW to 18 MW range. In 2011, KHI delivered 10 000 units worldwide. The company announced its first ultra-low emission model, which has achieved 9 ppm of NOx emission, with its M7A fleet in 2011.
Focusing on likely demand for the L30A, KHI said in the aftermath of the Japanese earthquake in March 2011, the issue of energy security has become “highly evident” and the need for on-site power generation has been increasing in the country. It added that, worldwide, considerable demand is expected because of an ever-increasing power demand and increasingly stringent environmental protection regulations.
The company claimed the L30A is able to provide a flexible solution for such demands as an ideal gas turbine combined with a waste-heat recovery boiler in a cogeneration and combined heat and power (CHP) plant with a steam turbine.