Preventive maintenance works of Main boiler Eco Hopper ash pan system and associated auxiliaries of unit No 4 and 5 of 2x500 MW BTPS Anpara

Amount

Preventive maintenance work of Scanner/TV cooling fans, Oil/Coal burner, Igniter guide pipes, BCP inlet/outlet valve and other associated equipment, keeping watch on abnormal sound of boiler first pass, second pass of pressure parts, attending coal dust leakage from Mill outlet Elbow to fuel inlet Elbow by applying sodium silicate & asbestos powder round the clock of boiler unit No. 4&5 of 2x500 MW, BTPS, Anpara. Transportation of consumable such as sodium silicate & asbestos powder etc. from central stores/site store up to work site and their proper stacking shall be maintained. Scope of work shall be as under a. Checking and attending fault of oil burner guns in every shift. b. Attending oil/steam leakages from oil guns in every shift. c. Attending minor nature leakages of water/steam from H.P./L.P. valves of main boiler from 0 to 80 mtr. floor of boilers as per site requirement. d. Attending coal dust leakage minor nature by applying sodium silicate and asbestos powder as per site requirement. e. Checking of abnormal sound of boiler pressure parts 1st pass/2nd pass. f. Checking and inspection of main holes/peep holes of boiler pressure parts from 11 mtr to 80 mtr of boiler and closure of the same if found open. g. Checking/Inspection of any abnormal sound of Flame Scanner/T.V. cooling air fan which is in service for smooth running/stability of boiler.

Preventive maintenance of all Flushing apparatus of economizer ash pan system, removal of chocking, their regular cleaning and disposal of ash in three shifts (each of 08 hrs.) Scope of work shall be as under a. Regular hammering of economizer ash pan transition pipes to avoid choking of economizer hoppers. b. In case of choking of hoppers, ash gates to be closed, transition pipes to be dismantled and ash/foreign materials to be removed through the discharge pipe and flushing apparatus. c. After removal of choking, transition pipes to be fixed in position, gaskets of proper size to be provided and bolts to be tightened ensuring no leakage of ash. d. Removal of foreign materials at regular interval from the flushing apparatus to avoid choking/overflow. e. Replacement of flange gasket of flushing water line of Eco.ash pan system, after isolation of the system in case of water leakage from the flange/pipeline. f. Greasing of pad liners of expansion piece of flushing apparatus. g. Opening of ash gates to be regulated to maintain controlled ash flow from the flushing apparatus at the time of soot blowing of pressure parts of main boiler.

Removal of choking of interconnecting Ash/ slurry pipe from Ash Pan to central disposal pipe of Eco. Hopper Ash disposal system.

Servicing/ replacement of Plate Valve of Eco. Ash pan System.

Repairing of eroded section of Eco. Ash Pan System/ pipe line by removal of worn out portion and providing patch of 6-10 mm thick M.S. Plate.

Servicing of Butter Fly Valve/ Flushing water nozzles of Eco. Ash pan System.

Removal, disposal and cleaning of Ash/ Slurry, foreign materials accumulated due to overflow of Eco. Ash Disposal System from the following places of Boiler and cleaning the area by compressed air.

Top of the Hot Secondary Interconnecting Duct.

Complete Platform at Economiser Ash Hopper Area.

Complete Platform below Economiser Ash Hopper. Area/ Duct across Guide bearing area of Sec. APH - A & B.

System line up for filling of Feed water through Boiler Feed Pump for Hydraulic Test of Boiler, normalization of the same after Hydraulic Test and making the System ready for Boiler Light up. Works involved are as under : a. Closing of Bottom Ring Header Drain Valves, Primary Super heater, Tertiary Super heater, Back Pass, Final Super heater, Economizer and all other related Drain Valves in the circuit. b. Opening of Boiler Drum, Economizer, Primary, Secondary, Tertiary, Final Super heater, Main Steam line all other related Air vent Valves in the circuit. c. During filling of Boiler through Feed Pump after achieving Full Drum Level, air vent valves to be closed one by one sequentially on complete release of air from the System. d. After achieving 160 Kg/ sq. cm. of Hydraulic Pressure all the Safety Valves of Super heater and Boiler Drum must be gagged. e. On completion of Hydraulic Test and sustaining the Pressure of 205 Kg/ sq. cm. and observing drop in Pressure for 05 minutes, Pr. to be released slowly by opening Main Steam Air Vent Valves and Safety Valve Gags to be removed at a Pr. of 170 Kg/ sq. cm. Pressure to be hold at 100 Kg/ sq. cm. for internal inspection of Pressure Parts by closing the M.S. Vent. f. After successful Hydraulic Test, Boiler to be depressurized through air vent, Drum level to be brought at normal by draining, system to be normalized for light up and all inspection windows and manholes to be closed properly.

Replacement of Ash Disposal drain line of Dia. 200-320 mm of Economizer Ash disposal system by cutting & removal of damaged pipes and fitting and Welding of repaired /new pipes by suitable welding electrode.

SHAKSHI ENGINEERING CO.