PAY B A C K P R O F I L E :
One-Shot Balancing For A Gas Turbine
How collaboration between OEM, End User, and the Bently Nevada ® team saved over 1MM USD
Field Services Manager, Bently Nevada® Products GE Energy firstname.lastname@example.org
William C. Foiles
Rotating Equipment Specialist BP email@example.com
Editor’s Note: Mr. Foiles, a rotordynamics specialist with GE Energy at the time the events in this story took place, now works for BP. This case history transpired in early 2001, nearly a year prior to the acquisition of Bently Nevada by GE. Although the case history describes the remarkable results achieved by cooperation between the customer, the turbine manufacturer (in this case, GE), and Bently Nevada, this level of OEMcollaboration was not then – or now – intended to be unique to GE. The Bently Nevada team continues to work in the strictest confidence with all OEMs, both in the supply of condition monitoring products and in the application of machinery diagnostics expertise. We welcome the opportunity to publish additional articles where collaboration with any of our OEM customers produced favorable results for allparties.
Introduction This case history chronicles a machinery balancing job at a large Asian chemical complex, demonstrating how collaboration between the customer, the machinery OEM, and Bently Nevada service personnel achieved substantial improvements in the cost and time required to execute this service. The Setting The chemical complex is fully integrated with an adjacent refinery, producing acombined total of over one million tons per year of propylene, ethylene, and other petrochemical derivatives. The world-scale operation also contains an integrated cogeneration facility for powering both the refinery and chemical complex. Unlike many cogeneration installations where electricity is considered the primary “product” and steam is considered a byproduct, this petrochemical complex’s useof cogeneration is just the opposite: steam is the essential product, required by the hydrocarbon cracking process; electricity, in this instance, is the byproduct. This explains why the economics and machinery objectives that drive a cogeneration process will often differ from the power generation sector to the petrochemical sector. When electric power is the primary product, machineryefficiency is paramount because competitive pressures focus on the lowest cost of generation. In contrast, the continuous processing industries, such as this chemical complex, have processes with enormous downtime costs – often millions of dollars per day. When a cogeneration process cannot run, steam cannot be produced, and the multi-million-dollar-perday petrochemical process that relies upon the steammust likewise stop.
END USER’S PRACTICE IS TO HAVE
GAS TURBINES RUN WITH VERY LOW VIBRATION LEVELS.
VIEW AS SEEN FROM DRIVER END
4YD (UCZ-710) 3YD (UCZ-707) 3XD (UCZ-708)
LOW-SPEED SHAFT Kφ (UCZ-720) 7YD (UCZ-715) 7XD 8YD (UCZ-716) (UCZ-701) 8XD (UCZ-702)
GAS TURBINEGEARBOX GENERATOR
HIGH-SPEED SHAFT Kφ (UCZ-721) 2YD (UCZ-704)
1XD 1YD (UCZ-706) (UCZ-705)
2XD (UCZ-703) 5YD (UCZ-712) 5XD (UCZ-711) 6YD (UCZ-714)
HIGH SPEED GEAR SHAFT
LOW SPEED GEAR SHAFT GEAR END VIEW AS SEEN FROM DRIVER END MACHINE TRAIN DIAGRAM FOR GAS TURBINES SHOWING TRANSDUCER ARRANGEMENT | FIG. 1
The cost of this lost production fareclipses machinery efficiency concerns. As a result, machinery reliability – not efficiency – is paramount. Machinery At the heart of the cogeneration facility are two identical GE MS6001FA (“6FA”) single-shaft industrial gas turbines, driving
3000 rpm generators through speed-reducing gearboxes. The machines are rated at 65MW and operate at 5,230 rpm. There are eight radial bearings in each...