Apr 26

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  • How can problems of "excessive vibration or noise" due to piping strain be avoided on steam turbines?
  • The inlet as well as exhaust steam lines should be firmly supported to avoid strains from being imposed on the turbine.
  • Adequate allowance should be made for expansion of steam pipes due to heat.
  • How  the deposits in turbine be removed?
    • Water soluble deposits may be washed off with condensate or wet steam.

    • Water insoluble deposits are removed mechanically after dismantling the turbine.

    • Experience shows that water soluble deposits are embedded in layers of water-insoluble deposits. And when the washing process is carried out, water soluble parts of the deposit dissolve away leaving a loose, friable skeleton of water-insoluble deposits which then break loose and wash away.

  • How the fatigue damage on high-pressure blades be corrected?
  • Fatigue-damage on high-pressure blades arises due to vibration induced by partial-arc admission. This can be corrected by switching over to full arc admission technique.

    • How the misalignment of Flanges be rectified?

    The bolts holding the flanges together are to be tightened. The coupling is to be checked for squareness between the bore and the face. At the same time axial clearance is to be checked.

    • How the problem of excessive speed variation due to throttle assembly friction be overcome?

    The throttle should be dismantled. Moving parts should be checked for free and smooth movement. Using very fine-grained emery paper, the throttle valve seats and valve steam should be polished.

    • How the problems of vibration and fatigue arise in steam turbine blades?
    • These arise due to flow irregularities introduced because of manufacturing defects, e.g. lack of control over tolerances.
    • System operating parameter, e.g. low flow may excite various modes of vibration in the blades.
  • How does solid-particle erosion occur?
  • Solid-particle erosion, i.e. SPE occurs in the high-pressure blades. And it takes place when hard particles of iron exfoliated by steam from superheater tubes, reheater tubes, steam headers and steam leads strike on the surface of turbine blades.

    • How does the internal efficiency monitoring lead to the detection of turbine deposits?
    • Process heat drop.
    • Adiabatic heat drop.
    • The process heat drop and adiabatic heat drop are obtained from a Mollier-Chart for the corresponding values of steam parameters – pressure and temperature – at initial and final conditions.
  • How is a flyball governor used with a hydraulic control?
  • As the turbine speeds up, the weights are moved outward by centrifugal force, causing linkage to open a pilot valve that admits and releases oil on either side of a piston or on one side of a spring-loaded piston. The movement of the piston controls the steam valves.

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    4 Responses to “Question And Answer For Steam Turbine | Question And Answer On Steam Boiler | Interview Questions On Steam Turbine”

    1. CE says:

      We downsized the plant and no long need the steam capacity – plant operates 24/7 – the plant has two boilers on-line sharwith a boiler on stand-by

      We have two steam boiler with a capacity of 55,500#/hr steam each. Plant needs 45,000#/hrs steam (winter) and about 32,000#/hr steam (summer) , both boiler are on line with a load share of about 55/45%.

      We are having issues with our feed water pump reliability (destruction of the pumps internal within a year after repairs) during to having too much pump for our present needs. Pump vendor analysis is the pumps are oversized and operating in an area of the pump curve that destroys the pump.

      Correction is to install smaller capacity pumps

      Now my question – when doing this are we voliating any boiler codes and or safety issues due too the fact that we would downsized the pump capacity and cannot provide the maxium feed water based on the boiler tag / design?

    2. CE says:

      We downsized the plant and no long need the steam capacity – plant operates 24/7 – the plant has two boilers on-line sharwith a boiler on stand-by

      We have two steam boiler with a capacity of 55,500#/hr steam each. Plant needs 45,000#/hrs steam (winter) and about 32,000#/hr steam (summer) , both boiler are on line with a load share of about 55/45%.

      We are having issues with our feed water pump reliability (destruction of the pumps internal within a year after repairs) during to having too much pump for our present needs. Pump vendor analysis is the pumps are oversized and operating in an area of the pump curve that destroys the pump.

      Correction is to install smaller capacity pumps

      Now my question – when doing this are we voliating any boiler codes and or safety issues due too the fact that we would downsized the pump capacity and cannot provide the maxium feed water based on the boiler tag / design?

    3. CE says:

      We downsized the plant and no long need the steam capacity – plant operates 24/7

      We have two steam boiler with a capacity of 55,500#/hr steam each. Plant needs 45,000#/hrs steam (winter) and about 32,000#/hr steam (summer) , both boiler are on line with a load share of about 55/45%.

      We are having issues with our feed water pump reliability (destruction of the pumps internal within a year after repairs) during to having too much pump for our present needs. Pump vendor analysis is the pumps are oversized and operating in an area of the pump curve that destroys the pump.

      Correction is to install smaller capacity pumps

      Now my question – when doing this are we voliating any boiler codes and or safety issues due too the fact that we would downsized the pump capacity and cannot provide the maxium feed water based on the boiler tag / design?

    4. You actually make it seem really easy with your presentation however I to find this matter to be actually one thing which I feel I might by no means understand. It seems too complicated and very vast for me. I’m taking a look ahead to your subsequent post, I will try to get the dangle of it!

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