2.2.1.1 Bottom Ash Handling System
Scope under this specification for bottom ash handling system starts from the boiler furnace bottom to the disposal of ash slurry in the sump of combined ash slurry pump house, consisting of : -
(i) The bottom ash handling system employing W-type water impounded hoppers and jet pumps, the plant shall include, at least, the following basic elements.
(a) Two (2) numbers water impounded bottom ash hoppers of structural steel complete with hydraulically operated discharge gates, refractory cooling arrangement, hopper overflow, water seal boxes, sluicing headers with nozzles, seal trough with overflow connection, refractory lining, access doors, observation and inspection glass windows, poke holes supporting steel structures, platforms, stairs and all accessories as specified and as required.
(b) Eight (8) numbers, clinker grinders complete with drive motors, fluid coupling, gear reducers and accessories as specified as required.
(c) Eight (8) numbers jet pumps alongwith discharge gate housing, using flushing and drain connection, etc. as specified and required.
(d) Four (4) length of bottom ash slurry transportation MS lines complete with pipe bends, fixtures, elbows, gaskets, nuts, bolts, structural steel supports and other accessories as specified and as required, from the outlet of jet pumps to the ash slurry sump in the Ash slurry pump house.
(f) Eight (8) numbers solenoid operated pneumatically actuated knife edge gate valve at the outlet of jet pumps.
2.2.1.2 Economiser Ash Handling System
(a) Thirty six (36) numbers flushing equipment below economiser/economiser bypass duct ; primary and secondary air preheater hoppers, complete with flushing nozzles, expansion joints, vertical pipe connections, gaskets, slurry discharge and overflow pipes and necessary fixing clamps and structural steel supports as specified and as required.
(b) Thirty six (36) numbers hopper isolation valve assemblies as specified complete with hopper connecting flanges, gaskets, nuts, bolts etc.
(c) MS disposal pipes for transfer of economiser and air preheater ash slurry from flushing apparatus to economiser/APH slurry trench complete with pipe bends, fixtures, elbows, gasket, supporting steel structure etc.
(d) Alloy cast iron liners for lining the slurry trenches.
(e) All instrument air piping to the various valves and instruments complete with fittings, valves, pressure reducing station, filters, flanges, gaskets, nuts and bolts, hangers, supports, etc.
(f) All instrumentation and control.
2.2.1.3 Dry Fly Ash Extraction System
Scope under this specification for dry fly ash extraction system starts from electrostatic precipitator and air pre heater ash collection hoppers outlet onwards and consist of :-
(i) For Vacuum Extraction System
(a) One (1) no. material handling valve/feed valve at the outlet of each ESP and duct hopper. One (1) no. chute isolation valve at the outlet of each ESP hopper and duct hopper. Expansion joints wherever required shall also be provided.
(b) Sixteen (16) nos. Mechanical vacuum pumps alongwith drive and accessories for two (2) units. Out of 16 nos. 8 nos. shall be working & eight (8) nos. shall be dedicated standby.
(c) Dry fly ash conveying cast iron pipes from ESP and duct hopper outlet onwards upto buffer hoppers/collector tanks complete with valves, specialities, bends, hydraulic/pneumatic actuators, structural steel supports, platforms, etc.
(d) Eight (8) nos. fly ash surge-cum-collection buffer hoppers each complete with supporting steel structures, platforms, stairs, aeration system, primary collector, secondary collector alongwith bag filter etc. or target box alongwith bag filter etc. for two (2) units.
(e) Sixteen (16) nos. collector tanks each complete with wetting heads, air-washers, seal boxes supporting structure, platforms etc. for both the units.
(f) All interconnecting compressed air/exhaust pipelines complete with valves and fittings and supporting steel structure.
(g) M.S. Disposal pipes for transfer of slurry from collector tank to fly ash slurry trench with supporting structures. Fly ash slurry trench shall be provided below collector tanks to transfer fly ash slurry from collector tanks to slurry sump in the combined ash slurry pump house as specified and as required.
(h) Alloy cast iron liners for lining the slurry trench upto ash slurry pump house.
(i) All nuts, bolts and jointing materials at flanged termination points.
(j) Mechanical ventilation (supply/exhaust fans) for different areas in vacuum/extraction compressor house and air conditioning of control panel rooms.
(k) Two (2) number (1 no. for each vacuum pump house/extraction air compressor house) pendant controlled electrically operated overhead travelling crane as specified complete with runway rails, necessary rail clamps, bolts, splice bars and stops for each of the runway.
(l) Four (4) x 100% instrument air compressors alongwith its air drying plants, air receivers complete with motors, valves, pads and pipelines alongwith supporting steel structures to meet the complete requirement of ash handling plant such as actuation of material handling, segregation valves ; various water and airline valves, slurry valves ; bag filter cleaning etc.
(m) 2 x 100% capacity aeration blowers per unit (i.e. total four (4) numbers) for aeration of buffer hoppers complete with heaters, valves, pipelines including supporting steel structure, insulation, silencer, filters and all other accessories as specified and as required.
(n) All instrumentation and control.
2.2.1.4 Dry Fly Ash Transportation and Storage System
Scope under this specification for dry fly ash transportation and storage system starts from the outlet of buffer hoppers and consists of :-
(a) Sixteen (16) nos. of pump tanks/air locks/eductors/ash transporters, two each at the outlet of each buffer hoppers, for transportation of dry fly ash to storage silos.
(b) Three (3) nos. transport air compressors alongwith silencer, filter, drive motor, after cooler alongwith all other accessories and supporting structures, platforms etc. as specified and as required.
(c) Three (3) nos. refrigerant type air dryers alongwith accessories as specified and as required.
(d) Three (3) numbers air receivers alongwith safety relief valve, automatic drain trap and other accessories as specified and required.
(e) Three (3) lengths of cast iron pipes of adequate thickness for fly ash conveying from surge/buffer hoppers to storage silos, including pipe rack, trestles, platforms, access stairs and other associated supporting steel structure and other accessories as required.
(f) Two (2) nos dry ash storage structural steel silos each of 1000 M³ effective capacity and complete with an aeration system, dust separators and all other accessories as required and as specified. The silos shall be complete with all fittings, accessories and supporting steel structures access staircases, platforms, stainless steel liners as required for safe and reliable operation and maintenance of dry fly ash storage system.
(g) Aeration plant consisting of three (3) numbers silo aeration blowers (one for each silo+one common standby) complete with heaters, valves, pads and pipelines including supporting steel structures, insulation, silencer, filter and all other accessories for aeration of silos.
(h) One (1) no. air receiver alongwith safety relief valve, automatic drain trap and other accessories complete with supporting steel structures to meet the complete requirement of ash storage silo such as actuation of material handling, segregation valves ; various water and airline valves, slurry valves ; bag filter cleaning etc.
(i) Target box and bag filter assembly alongwith pulse jetting arrangement, fan units etc. and other accessories.
(j) Slide plate valves below storage silos.
(k) Two (2) numbers of hydro-mix conditioner units alongwith drive motor, ash feeding & measuring arrangement, one (1) number for each silo, alongwith associated water piping and valves, for unloading the conditioned fly ash into trucks.
(l) Three (3) nos.. water booster pumps (1 for each unloader + 1 common standby) for conditioned ash unloaders alongwith drives and controls as required and specified.
(m) Two (2) number of Dry fly ash unloaders (one for each dry fly ash storage silo) alongwith rotary feeders, telescopic chutes and other accessories as specified and as required.
(n) All necessary hydraulic or pneumatic actuators.
(o) All interconnecting compressed air pipelines complete with valves, fittings, pipe rack and supporting steel structure.
(p) 2 x 100% wash water pumps alongwith drive motor and accessories in silo area alongwith dedicated hose pipe.
(q) 2 x 100% vertical sump drainage pumps alongwith drive motor and accessories in silo area to pump the accumulated ash water to the combined ash slurry disposal pump house sump including piping alongwith necessary valves, fittings, supports, etc. as specified as required.
(r) Two (2) number pendant controlled electrically operated overhead travelling crane one (1) number each in transport air compressor house and silo area utility building to handle the equipment in the transport air compressor house and silo area utility building pump & blower room, as specified complete with run way rails, necessary rail clamps, bolts, splice bars and end stops for each of the runway.
(s) All nuts, bolts and jointing materials at flanged termination points.
(t) Mechanical ventilation (supply/exhaust fans) for different areas in utility building and air conditioning of control panel rooms.
(u) All instrumentation and control.
2.2.1.5 Ash Slurry Disposal System
Scope under this specification for ash disposal system starts from ash slurry sump in the combined ash slurry pump house and consists of :
(i) In the combined Ash Slurry pump house
(a) Four (4) streams of horizontal ash slurry disposal pumps, complete with drive motors, variable speed hydraulic couplings, for first stage pumps and fixed belt drive arrangements for subsequent stages, base plates, foundation bolts, inserts, embedments and accessories as specified and as required.
(b) Four (4) lengths each of 6 km length of ash slurry disposal pipelines (excluding the length of bends & fittings) from the ash slurry pump house to the ash dyke including the lines around the ash dyke and extensions into the dyke at a number of discharge points complete with basalt lined bends, specialities, fittings, fixtures, pipe couplings, gaskets, nuts, bolts, clamps, embedments, structural steel supports for piping system and other accessories.
(c) Complete ash slurry piping alongwith bends, supports alongwith bolts, nuts, clamps etc. inside the ash slurry pump house. All the piping inside the pump house shall be basalt lined.
(d) Eight (8) nos. adequately sized motor operated or solenoid operated & pneumatically actuated metal to metal seated knife edge gate valve/100% tight shut off rubber lined knife edge gate valves/plug valves shall be provided at the suction and discharge of combined ash slurry disposal pumps.
(e) Two (2) nos. slurry sump compartment isolation valves.
(f) Adequate no. of manually operated plate valves at the slurry disposal pipelines outlets in the dyke area as specified and as required.
(g) Two (2) nos. vertical sump drainage pumps with motors complete with piping, valves, fittings, supports, inserts, sleeves etc.
(h) Alloy Cast iron liners (as specified) for lining the ash slurry sumps.
(i) One (1) no. pendant controlled electrically operated overhead travelling crane to handle the equipment in ash slurry pump house, as specified complete with runway rails with necessary rail clamps, bolts, splice bars and end stops for each of the runway.
(j) Mechanical ventilation (supply exhaust fans) for different areas in ash slurry pump house and switchgear rooms.
(k) All instruments and control .
2.2.1.6 Ash Water Pumps, Water Piping and Accessories :
(a) All types of Ash water pumps namely Bottom ash LP water, Bottom ash HP water, Fly ash HP water, Flushing water pumps etc. complete with drive motors, base plates, foundation bolts, inserts, embedment and accessories as specified and as required. Complete ash water pipe lines, valves, fittings, pipe rack, structural steel supports for piping system and other accessories as specified and as required. The ash water pumps namely Bottom ash LP water, Bottom ash HP water, Fly ash HP water, Flushing water pumps are to be located in Ash water pump house.
(b) Seal/cooling/other water pumps and motors complete with all the accessories of drive and mounting as specified and as required.
(c) Bottom ash over flow water system
(i) Two (2) number Bottom ash over flow water storage tank, one (1) number settling tank and one (1) number surge tank, including their structural steel supports.
(ii) Four (4) numbers (3×50% capacity) bottom ash over flow water pumps complete with drive motors, variable speed hydraulic coupling and other accessories as specified and required for pumping BA hopper cooling water overflow from Bottom ash overflow water storage tank/sump to settling tank.
(iii) Bottom ash overflow water pipes from BA hopper to BA overflow water storage tank, from BA overflow water tank/sump to suction of BA overflow water pumps, from discharge of BA overflow water pump to settling tanks complete with valves, fittings, structural steel supports etc. Overflow transfer pipes to transfer clear water from surge tank to overground sump of ash water pump house, by gravity flow.
(iv) Two (2) nos. sludge pumps, to remove sludge from settling & surge tank to sump of combined ash slurry pump house.
(v) Any treatment facility required to ensure that bottom ash over flow water total suspended solids is restricted to 100 ppm.
(d) All ash water and seal water piping to all the equipments and sumps complete with fittings, valves, strainers, flanges, gaskets, nuts, bolts, hangers, supports, flushing nozzles, agitating nozzles, etc. as specified as required.
(e) All overflow and drain piping from various equipment to the nearest plant drainage as required.
(f) One (1) no. pendant controlled electrically operated overhead travelling crane to handle the equipment in Ash water pump house, as specified complete with runway rails with necessary rail clamps, bolts, splice bars and end stops for each of the runway.
(g) All instrumentation & control.
shivajichoudhury
