O&_M mech
Transcript of O&_M mech
-
7/31/2019 O&_M mech
1/27
-
7/31/2019 O&_M mech
2/27
-
7/31/2019 O&_M mech
3/27
-
7/31/2019 O&_M mech
4/27
-
7/31/2019 O&_M mech
5/27
-
7/31/2019 O&_M mech
6/27
-
7/31/2019 O&_M mech
7/27
-
7/31/2019 O&_M mech
8/27
-
7/31/2019 O&_M mech
9/27
-
7/31/2019 O&_M mech
10/27
-
7/31/2019 O&_M mech
11/27
-
7/31/2019 O&_M mech
12/27
-
7/31/2019 O&_M mech
13/27
-
7/31/2019 O&_M mech
14/27
-
7/31/2019 O&_M mech
15/27
-
7/31/2019 O&_M mech
16/27
OPERATION
PREPARATION AFTER MAINTENANCE
Check the precipitator internals and remove the
tools and other foreign materials.
Check all the insulators visually.
Inspect the rapping motors and top-up with oil.
Run the rapping motors and ascertain that they
function normally.
Check that the heating elements.
-
7/31/2019 O&_M mech
17/27
Check the dielectric strength of transformer
oil
Megger and test all the fields on air load.
Ensure that the ash handling system is
working properly.
-
7/31/2019 O&_M mech
18/27
START UP PROCEDURE
Switch on the heating elements at least 24
hours before the start up of the boiler.
Switch on the rapping mechanisms as soon as
the boiler is lighted up.The HVR shall not be energised until the gas
temperature is above 100C.
-
7/31/2019 O&_M mech
19/27
OPERATIONAL CHECKS
Check the normal function of Precipitator
Logging of readings hourly.
Record the failures and outages.
-
7/31/2019 O&_M mech
20/27
SHUTDOWN PROCEDURE
Switch off the fields when the gas temperature isbelow acid dew point.Continue the operation of the rapping motors in
intermittent mode for 4hrs.
Evacuate the ash from all hoppers.The access doors may be opened after following
the interlock sequence.
-
7/31/2019 O&_M mech
21/27
SHUTDOWN INSPECTION
Inspect the internals for :
Snapped or loose wires.
Excessive ash accumulation.
Dislocation of shock bars, shock bar guides and CE
Rapping system, hammers, plain bearing shaft etc
Insulators
Disconnecting switch and contacts.
All heating elements
Any other abnormality.
-
7/31/2019 O&_M mech
22/27
MAINTENANCE
GENERAL
Ensure the guide vanes, splitters, deflector plates
on the gas distribution screen as per original.
R , .
Inspect for corrosion, wear and tear of ,
, .
.
-
7/31/2019 O&_M mech
23/27
MECHANICAL SYSTEM
(i) Collecting Electrode system
Check the alignment of CE, shock bars and
guides.
Replace the shock bars/shock pads if worn out
excessively.
Check the rapping mechanism if dust build up is
excessive.
Tack weld all the fasteners after tightening. Care
should be taken not to tack weld the HSFC bolts if
used for CE and shock bars
-
7/31/2019 O&_M mech
24/27
(ii) Emitting Electrode system
Check the emitting electrodes forexcessive electrical erosion and snapping.
Remove the eroded/snapped electrodes, if
any.
Care shall be taken not to disturb the
healthy electrodes while replacing with
new electrodes.
Wherever the access is difficult, the
intervening electrodes may be unhooked
-
7/31/2019 O&_M mech
25/27
, .
.
-
7/31/2019 O&_M mech
26/27
Insulators
The insulator shall be inspected during shutdown for cleanliness, cracks and rigidity of metal
parts
Dusty insulators should be cleaned with Carbon
tetrachloride / Petrol in both inner and outer
portions.
Cracked insulators should be replaced.
Support insulators shall be replaced, if required,
with the help of lifting tool and alignment jig as
per procedure.
-
7/31/2019 O&_M mech
27/27
AIR LOAD TEST AFTER MAINT.,
Please ensure:
All foreign materials are removed.
All heaters are energized
Meggering of fields ( around 500 Meg Ohms)
Charge the fields with still air load and ensure:
Fields building up up to rated current and kV without
sparking. Incase of sparking attend the discrepancy and
repeat the test.
Air load test is a must after every maintenance of fields.