ISOPur Rids Boiler Feed Pump of Sludge and Varnish

Hayri Yaba, ISOPur Fluid Technologies Inc. Teoman Kupeli, Trans Ticaret Company Gerald Munson, ISOPur Fluid Technologies Inc.
Tags: varnish, contamination control

A test was conducted for the purpose of evaluating the ISOPur system in its performance of oil purification and the cleaning (de-varnishing) of equipment internal surfaces - which operates with balanced charge purification (BCP™) technology. Testing was conducted at one of the plants of the Turkish Electric Generating Company (EUAS), and reports the results of the information for all the plants within EUAS.

Plant Where Tested
EUAS Tuncbilek Thermal (Coal) Power Plant in Tuncbilek, Turkey

Technology Tested
ISOPur 101 Balanced Charge Purification (BCP)

Equipment to Which the BCP Unit was Connected
No. 5 Group 3 Boiler Feed Pump (BFP)

Test Start Date
The BCP unit has been installed since January 22, 2004.

Oil Analysis Date
The first sample was analyzed January 29, 2004. Samples were then taken and analyzed on a weekly basis. All of this analysis data is included in this report.

Findings
The BCP unit was installed on the No. 3 boiler feedwater pump (BFP) of unit 5 on January 22, 2004, and was operated until July 2, 2004, excluding the periods during which the No. 3 BFP was not operational due to scheduled maintenance on the No. 5 Group unit.

The unit ran for a total of 60 days. During this time, the prefilter was changed twice, and cleaned occasionally. Test results for the No. 3 BFP are compared to group 5 No. 1 BFP, a similar unit. Additionally, a before-and-after comparison was also made on the No. 3 unit.

Prior to the test period, the existing filtration system required cleaning two times per week due to plugging alarms. Throughout the test period, no new oil was added to the No. 3 BFP.

Plant operational data reports during and following the test period showed:

  1. Following cleaning during the first week of operation, the unit has not had an alarm from plugging.
  2. Improved color and viscosity of the oil.
  3. The system indicated no presence of moisture.
  4. White metal bearing temperatures of the pump and the Voith clutch dropped by 11°C by the end of the 60 days of operation.

A comparison of observations between the values of No. 3 BFP before and after BCP and between the values of No. 3 BFP vs. No. 1 BFP during the BCP test are stated below.

In contrast to the No. 3 unit, during the five-month test period No. 1 BFP performed the following:

  1. Registered 50 alarms and received two oil changes (720 liters each).
  2. During the 36 hours following the second oil change, the filter required cleaning on an hourly basis.
  3. The oil was analyzed June 28, 2004, following operation of the existing filter for No. 1. The oil was characterized as light brown.
  4. The BCP system was installed in lieu of a planned oil change on June 29.

On July 1, 2004, the oil was sampled again, and the color had lightened to a color clearer than the original. The oil analysis from that test date is shown below.

The No. 1 and No. 3 BFP systems were disassembled to conduct a thorough inspection and to conduct planned maintenance checks on each. There was an evident reduction in varnish buildup on the gear teeth and gear shaft on the No. 3 BFP. It was reported to appear to be in its original (new) condition (Figure 1).


Figure 1

After disassembling the Voith turbo, the surfaces and bottom parts of the vanes were also compared. Again, No. 3 BFP was observed to be shiny. There was a distinct difference in appearance of the turbo vanes of the two separate gearboxes (Figure 2).


Figure 2

The thickened and sticky oil that had always been observed in the bottom parts of the vanes of the turbo was absent. Additionally, the oil that is collected in the oil pockets of the bearings, which is normally muddy and full of deposits, was observed to be clear and transparent (the color of glycerine) in unit No. 3.

The Voith parts of the No. 1 BFP were black and could not be cleared despite the cleaning with sandpaper.

Conclusion
The performance results were better than expected. During the trial period, there were no oil-related problem alarms and the oil properties (oil color and viscosity values) improved. The heat exchanger performance has improved and bearing temperatures have stayed down.

Observations and photographs have shown that the instrument purifies the oil, cleans the already formed deposits from machine surfaces, and prevents the reforming of the deposits on the surfaces that can cause serious problems.

Site maintenance management personnel also noted that the maintenance and operation costs of the BCP system are negligible versus other purification options.


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