Please visit Boiler Tube Research Part 1 (Re-heater) for previous explanation.

Visual Inspection.
Two pipes re-heater damaged and are still attached can be seen from figure 3.3. Temporary conditions pipe 3 and 4 pipe received can be seen from figure 3.4 and 3.5.




A visual inspection then will be on pipe 3.The results can be seen from figure 3.6 to 3.12



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The residual thrust of the balance drum is taken up by the thrust bearing. This arrangement has been chosen for its reliability, especially under transient conditions and for its ease of assembly (eliminate spring load axial bearing).

An additional advantage is that through measurement of the balance water and quantity and the conditions of the internal clearances, the pump efficiency can be judges easily and reliable at any time.



leakage at the balance drumof the main pump is returned to the main circuit upstream from the main filter. Its flow-rate corresponds to the pump's mechanical wear. For the purpose of diagnosis, a permanent diaphragm is mounted to measure the flow-rate by means of a differential pressure gauge.




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Specimen pipes number 3 and 4 is a segment of the re-heater pipes. Re-heater serves to heat the steam coming out of the back of HP Turbine (High Pressure) gas combustion results by leveraging the relative temperature is still high.

This Heating is aims to raise the efficiency of the system as a whole. The most dominant of heat transfer on the re-heater is by convection.



Radiation heat transfers on re-heater give a very small effect so this process usually negligible. Steam temperature entrance re-heater is 335C with pressure equal 42.8 kg/cm2, while temperature a discharge is 541C with pressure 39 kg / cm2.

Steam is then used to drive IP Turbine (intermediate pressure) and after steam coming out from IP Turbine, directly used to twist LP Turbine (low pressure) without reheat.




From operational internal condition of pipe there would seen burden high work experienced by those pipes both in thermal and pressure from inside pipe. From outside pipe also suffered heat from flue gas although not as heat as in a pipe 2 (Secondary Super-heater).

The position of pipe 3 and 4 are horizontal position where right on the their above is a route of soot blower. Seen from the appearance of a disability that occur, on a pipe 3 experienced depletion on the outside of a pipe in an area sufficiently extensive and also a hole.

It indicates there is the process of erosion in the material of a pipe. While a pipe 4 seen from former a disability that happens, in the form of angular notches that taper and sharp, as well as the profile of disordered and the possibility of magnitude happens mechanical contact between the pipe 4 with other material in a condition in re-heater when contact, the other material having the power of larger than material pipe 4.

Additional information obtained discovered that soot blower in this area has ever had stalled in the sense of no return to the original position.

Operational conditions and history operational of information obtained that those pipes has operated about 10 years that is, since 2004. Pipe yet undergone alternation because the design of pipe life time is 30 years. According to information obtained, specifications material pipe 3 and 4 pipe is SA-213-T12. Specifications detail of pipes and operational condition described on tables 3.1 up to table 3.3.



To be continue to Boiler Tube Research (re-Heater) Part 2.

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