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Drawing on its experience with jet engines, GE is rolling out a powerful gas turbine that aims to lower costs and save platform space in LNG operations.
As the energy industry works its way through a sustained low price environment, GE Oil & Gas has amplified its focus on leveraging aviation technology to help lower costs for customers.
Leveraging the legacy aviation products and combining them with existing technologies for use in liquefied natural gas (LNG) facilities will reduce the footprint and weight needed for mechanical drive applications, according to the company.
To that end, GE has designed a 65-megawatt, 43% simple cycle efficiency aeroderivative gas turbine called the LM9000 that can be used for LNG applications as well as for simple cycle, co-generation and combined cycle power generation.
Daniel Kempf, general manager of aeroderivative gas turbines at GE Oil & Gas, says the LM9000 is also designed for offshore applications to run large generation equipment required for powering subsea pumps and similar kit.
“I love taking aviation technology and repurposing it,” Kempf says.The base engine for the LM9000 is the jet engine GE 90-115B used for the Boeing 777-300ER and 777-200LR.
The design team, he says, is engineering a machine specifically to serve the floating LNG market while drawing on existing technology from the aviation division.
The team is reusing as much existing technology as possible and modifying specific parts of the machine as necessary to make it applicable for LNG use.
“I have a lot of confidence in the design,” Kempf says. “We had the opportunity to wring out the learnings on the aviation side.”
For instance, GE is leveraging the high-pressure turbine materials and advanced cooling technology of the GE 90-115B engine to enable continuous base-load operation with long maintenance intervals.
GE designed the LM9000 with LNG operations in mind, whether onshore or offshore.
The 65-megawatt turbine offers 20% more power and requires 25% fewer trains compared with other available technologies, Kempf says. “That’s a big capex advantage,” he says.
The team is setting the system up to allow for a longer-than-usual maintenance interval, which the company estimates will lead to a 20% cost of ownership improvement.
The typical hot section maintenance interval on such machines is 25,000 hours, but the LM9000’s recommended interval will be 36,000 hours. The turbine itself can be swapped out in 24 hours.
“That means less disruption, more availability for production,” he says. Kempf believes the LM9000 design, although still in progress, will be “a world-class machine for the future of LNG and power generation applications”.
When it comes to size and weight, Kempf estimates more than 20% savings in footprint size and around 10% savings in weight compared to GE’s legacy LM2500 equipment for the same level of output.
Kempf says the weight and footprint of the machine the engineering team is designing will offer the best available in terms of power density.
“Sixty-five megawatts in a small, lightweight package would be meaningful to our customer base,” he says.
That amount of power generation would provide around 1.2 million tonnes per annum of LNG output for the facility.
Multiple LM9000s could be grouped together to meet additional annual output requirements.
“On a dollar-per-million tpa basis, we think this is the best solution available,” Kempf says.The LM9000 will be a dual fuel system, running on liquid or gas fuel.
With an expectation that emissions requirements will only become more stringent in the future, the design team has focused on using dry low emissions (DLE) technology, which keeps nitrous oxide (NOx) emissions to 15 ppm.
The DLE combustor, manufactured using GE’s additive manufacturing capabilities, eliminates water use for emissions abatement.
The combustion system is based on the experience of more than 1000 GE aeroderivative gas turbines equipped with DLE systems having accumulated more than 25 million operating hours.
The LM9000 will take advantage of this experience to generate only 15 ppm NOx, 40% lower than other gas turbines operating at compressor pressure ratios higher than 32:1, according to GE.
“We think that will be a significant advantage, particularly onshore and nearshore,” Kempf says.
The LM9000 package includes a gas turbine, compression equipment, control system and auxiliary equipment to support the power generation functions.
The modular package design enables adaptability, shorter manufacturing cycles and quicker installation, according to the company.
The LM9000 is being set up so it can drive a centrifugal compressor without the need of helper motor to start the compression equipment. This, Kempf says, simplifies the train design.
“The beauty of the design is there is no gearbox required,” he says, which reduces costs as well as weight and footprint.
The primary challenge of adapting the jet engine for use in power generation offshore is ensuring the system will have the reliability and run time LNG customers will expect, he says.
GE has already adapted a couple of its engines for LNG applications, including the LM2500 and the LM6000, which have accumulated 1.6 million operating hours.
“We’re taking all the lessons learned from those applications,” he says, to ensure the reliability and availability in demanding conditions.
“A lot of LNG projects are near the equator. Hotter day operation is quite important to equatorial projects,” he says.
“This machine has good characteristics of holding power at temperature. It holds its output very well at higher temperatures.”
The LM9000 has a free power turbine, which enables high-efficiency power and speeds over a range of ambient conditions. It has an operating speed range of 2400 to 3780 rpm.
Development of the LM9000 involved engineers in the US and Italy from GE’s aviation and oil and gas businesses.
GE launched the development project in January 2015 in response to requests from customers for lower development and operating costs associated with LNG and power generation.
The team is well into the design phase and plans to test the turbine at GE’s machine testing facility in Massa, Italy. GE aims to make the LM9000 available for use in 2019.