barge 48M 50 hz

I. Overview

EEN deployed experienced gas turbine power plant personnel to perform a complete and thorough condition assessment of the entire plant and to perform the rehabilitation and commissioning works.

Works were completed on July 26, 2012, when the unit was successfully tested for 2 hours on Full Speed No load (FSNL). The gas turbine and all auxiliary equipment performed within the design parameters during the test. Vibration levels were all normal. Blade path temperature spread was minimal, indicating good and uniform burning of fuel at the nozzles. Temperatures of turbine disc cavity, bearings, and compressor discharge and rotor air were all normal during the test. No alarms or abnormal conditions were observed on any auxiliary equipment including the 1.7 MW black start generator. Generator was excited up to rated voltage while transformers, HV cables, switchgear and bus were energized up to 11.5 kV during the test.

Balance of plant equipment have been overhauled and commissioned and are now ready for continuous service. All necessary tests were performed on motors and pumps including insulation resistance, polarization index, temperature, vibration, together with functional and run checks. The generator, transformers, switchgear, motor controllers, together with LV and high voltage equipment have been groomed and commissioned to ensure electrical integrity. Power factor, voltage withstand, insulation resistance, ratio and polarity, protection scheme checks have been performed. Filtration and heating under vacuum was performed on the transformer oil in addition with dissolved gas analysis and dielectric breakdown testing to ensure oil quality. New inlet air filters and turbine insulation have been installed. Air inlet filter house has been repainted, cleaned and inspected. Preventive and corrective maintenance was performed to guarantee that balance of plant equipment is in optimum condition.

Turbine controls together with generator protective relays, metering, AVR and synchronizer have been replaced with a modern system from HPI, a reputable US based company. The new Allen Bradley PLC Turbine Control System was commissioned by a professional gas turbine controls company, HPI from Houston, Texas represented by Mr Paul Tovar. Sufficient spare input/output and analogue capacity has been installed to cater for future expansion and project specific changes.

Turbine vanes, blades and combustor parts have been replaced or repaired as needed for a normal hot gas path inspection as recommended by the OEM, Siemens Westinghouse. The parts/repair company used was Turbine Resources Inc. (TRI) from Euless, Texas. In addition we performed and inspection of the turbine from the inlet to the exhaust section as well as the journal and thrust bearings under the supervision of Frank Hick, a Siemens-Westinghouse gas turbine specialist with more than 35 years of practice in the field. Hot section parts were coated with special thermal barrier coating for use of different types of fuels including HFO. The gas turbine should not require another major inspection till after 48,000 equivalent base load hours.

Preservation measures are implemented to maintain the turbine and ensure its readiness for operation and in an optimum state of preservation.

In our professional opinion, the plant should be able to produce near the full OEM rated output corrected to ISO conditions. Following OEM maintenance recommendations, the unit can reasonably be expected to operate successfully for at least 25 years. Heavy duty gas turbines have indeed very 5   

long useful lives and we have seen similar turbines with over 40 years in the field and over 200,000 hours still operating satisfactorily.

II. Technical Specifications

Dynam is a power barge with a Siemens-Westinghouse W251B11 simple cycle gas turbine rated at 48MW on Natural Gas and 46.4Mw on Diesel Fuel at ISO conditions. The plant is a self-contained, electric power generating system ready to provide a quick solution to energy needs.

The Siemens Westinghouse W251B11 gas turbine is a heavy duty turbine consisting of 19 stage axial flow compressor, a combustor section with 8 combustor assemblies, and a 3 stage reaction type turbine. The single shaft engine is mounted on a bedplate. A lubrication pump, as well as associated pumps, and filters are located adjacent to the engine. The machine rotor is supported by two pressure lubricated pivoted pad journal bearings. A double acting tilting pad thrust bearing maintains axial shaft alignment. The nominal engine speed is 5,428 rpm, with the generator driven from the cold (compressor end) through a double helical reduction gear to obtain the 3,000 rpm required for 50Hz operation. The turbine is designed with features such as horizontally split sectionalized casing, two bearing support, turbine air cooling system, compensating alignment system, and axial–flow exhaust.

Westinghouse 1 X W251B11/12 ECONOPAC

Configuration: Gas Turbine, simple cycle.

Capacity: 1X48 MW ISO

Type of fuel (start): No. 1 distillate

Type of fuel (operation): Condensate/ Kerosene (HFO / Gas is possible)

Compressor: 19-stages axial flow

Turbine: 3 stages

Speed: 5,428 rpm

Speed Reduction: 3,000 rpm

Generator: Brush synchronous 3-phase, air cooled generator

65882 KVA, 11.5 kV, 50 Hz

Output: 11.5 kV - 50 Hz

GSU rating: 33 KV

Operating hours: 29,937

Starts: 845

Hours since last major overhaul: 0 (zero)

III. Gas Turbine

A full hot gas path and modified major gas turbine inspection was completed on the unit. All the major hot section parts have been replaced including turbine blades, stationary vane segments, transition pieces and combustor baskets. Torque tube and compressor section have been inspected and new compressor diaphragms were installed on rows 8 to 11. Turbine journal and thrust bearings were also checked and cleaned. All pertinent clearances and readings were taken and confirmed according to OEM recommendations.

During the Full Speed No Load test, the turbine ran very satisfactorily with no signs of rubbing and unusual noises during coast down. Blade path temperatures were uniform with minimal spread. Temperature levels on the disc cavity, journal and thrust bearings, and combustor and rotor air were all normal during the test. No leaks were found on the turbine and compressor casing or on the nozzle assembly and piping flanges. Vibration levels were all normal. Dial indicators were installed on both of the trunions to check for the expansion of the turbine as it heated up. Readings were found to be within OEM parameters and showed that the turbine was expanding uniformly. 7