Electrification of alkylation process with high speed motor drive system in a refinery

Directly coupled, variable frequency driven electric motors are replacing turbines driving process compressors due to advances in increased efficiency, precise process control and quick return on investment. In the oil and gas industry, high speed motors directly coupled to centrifugal compressors are also filling the need for more megawatts at higher speeds. In applications with demanding structure and space limitations, the smaller motors are the driver of choice when compared to turbines or conventional two pole motors with speed increasing gears. Motor manufacturers have developed specifically designed motors for these and other demanding applications instead of using higher-speed 2 pole or 4 pole standard motors. For the discussed application reliable and optimized motor designs, especially the motor frame, rotor-bearing, enclosure, bearing shields and cooling, are designed to meet stringent vibration and noise requirements, which are defined in specifications such as API, IEC and ISO. This paper discusses design and testing of 3750 kW induction motor with oil film bearings at a speed range of 3880-5300 rpm to replace an existing steam turbine in an United States refinery.