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Tuesday, 2 July 2013

MISC. ITEMS ERECTION PLAN FOR A BOILER IN THERMAL POWER STATION.

Coal Piping

Coal piping is the integral part of the Milling system . Pulverised coal and

air mixture gets transported through it to the furnace . One must give

attention to its erection and use of coupling ( with rubber band inside ) for

joining two pipes. Bad erection will result in coal air leakage en route. Coal

pipes up to first isolation gate from furnace to be erected and supported with

permanent support before first light up otherwise light up may delayed . This

is to avoid damage due to furnace expansion during Boiler light up.


A typical arrangement of coal pipes from Mills to furnace has been shown.

Raw Coal Feeder

Raw coal feeder feeds coal to mill as per requirement. One side of the feeder

is connected with coal Bunker through isolation gate etc. Other side is

connected with mill though a belt conveyor inside the equipment.The conveyor

speed can be varied as per load requirement. Weighing facility that Number of

kg coal being fed into mill is also available with RC feeder. Each mill is having

one dedicated feeder and cannot be changed during operation. Any shutdown

means shutting down of both the equipment. Feeders are housed around 19 M

floor of Mill bunker Bay. Feeder erection starts after completion of Bunker

erection and welding .Alignment of RC Feeder , Feed Pipes and Mills are

taken up at a time  to avoid mis- alignment of centre pipes.

MOVs , Dampers etc.

Motorised valves are extensively used in Boiler for remote and automatic

operation. If we take care very few basic requirements then subsequent

activities become smoother or easier.

- MOVs/ dampers  should not be dragged on the floor before erection.

 Otherwise damage  will bound to happen and replacement of material

  will take time.Use trolleys   to shift them in position and can be lifted

  with chain pulley block.

- Tag number as appeared in the PI Drawing should be painted on the

   body of the valves /dampers not on the junction box cover.

- Valve /damper torque switches are factory set therefore not to be tampered.

   Torque switch for close are used in the control and limit switch for open

   are used in the control. General philosophy is close must be torque tightened

   and open need not be required to be torque open. If there is change of

   philosophy then same should be clearly mentioned.

- Inside junction box cover control diagram of  that valve /damper to be pasted.

- Hand rail with platform should be erected where ever approach problem is

  there. No compromise to be done on that. We have seen fatal accident of our

 engineer on this count.

- A small canopy over the valves and damper is required wherever it is exposed

  to atmosphere  directly.

A few pictures attached herewith for clarity .


































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