The following is a case study from Sulzer pumps.
Efficient retrofit solutions from Sulzer Pumps optimize outputs
Location: Qatar
The Challenge:
The client had 3 crude oil export pumps with original duties of 305m3/Hr at 470 m head on an Offshore Oil Production Platform. Their revised production demands required a revised duty condition of 135 m3/Hr at 186m head from the existing unit. The client had considered purchasing 3 new smaller units or installing very costly Variable Frequency Drives (VFDs)to meet their requirements.
The Solution:
After thorough consultation, Sulzer Pumps provided a more cost effective solution which did not require additional space on the platform. Sulzer Pumps confirmed that the required duty could be met by de-staging the units from 6 to 3 stages, as well as reducing the impeller diameter of the remaining impellers .The client agreed to proceed with the first unit, where the scope included removal of the unit from the platform and re-installation upon completion of the de-staging.
Sulzer Pumps provided de-staging and trimming hydraulic solution which enabled the client to ensure site conditions were met whilst maintaining the existing pipe run foundations. This solution had greatly reduced the cost.
The detailed design and manufacture of the de-staging kits, that consisted of de-staging tubes, shaft protection sleeves, new throttle bush, throttle sleeve, centre bush and centre sleeve for each pump. De-staging of a pump affects the axial thrust generated which will result in a higher load being imposed onto the thrust bearing. To reduce this load, a recalculation of diameters of the throttle sleeve and centre sleeve was required to meet the de-staged duty condition which in turn resulted in new bushes being required as well.
Upon receipt of the pumps, the condition rotors were removed and disassembled. The shaft Total Indicator Runout (TIR) was checked prior to re-asssembly with the de-staging kit.
After completion of the de-staging assembly, the complete rotor was hydraulically balanced in accordance with Sulzer standards.
