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Bids Are Invited For Custom Bid For Services - Amc For Refractory Work, 1. Loading, unloading and stacking of materials at site/NLC store, will be at supplier scope 2. The scope of work includes the refractory work comprises the areas i.e. cyclone Inlet roof and cyclone roof, Cylinder, vortex finder, outlet duct, FGD/back pass and combustor including FBHE and Sub 1&2, Ash coolers, inlet header tube refractory works etc as directed by the corporation officers. The areas indicated are only indicative and not exhaustive. 3. The scope of work includes also the running maintenance for refractory pouring from outside at Boiler area, cerawool fixing from outside Boiler Area, debris cleaning, scrap shifting, material shifting etc as directed by NLCIL. 4. The scope of work includes cost and conveyance and all hire charges, labour charges for erection and dismantling of scaffolding works, labour charges for lifting, erection, grinding, cutting, welding etc of SS anchors and retainer plates of size 500 mm x 160 mm with two chamber 250 mm length as directed by NLCIL executives. 5. The required numbers of scaffolding pipes, clamps, platforms etc., are to be arranged by the firm as per requirement. 6. Refractory Dismantling and application of refractory castables by casting/ gunnitting machine,Brick work(refractory And Insulation) by welding anchors using electrodes and shuttering etc including gunnitting using machinery is in firm’s scope. 7. DM water/Potable Water supply will be provided by NLCIL at one point nearest Boiler at 0 m Elevation during shutdown for refractory application works. Firm has to make necessary arrangements like booster pump, pump set, pipe lines etc for lifting the water to required higher elevation location for the work as instructed by NLCIL executive. 8. Lighting arrangement is in the scope of Firm only. Electrical supply will be provided by NLCIL at the nearest points. Further extension of supply is in Firm’s scope. 9. Switch boards, supply extension boards with Male/female sockets are also in Firm’s scope. 10. All canteen facilities to workmen will be borne by firm’s scope. 11. The welding of anchor is in firm’s scope.The welding of Anchors on pressure parts will be done by NLCIL- IBR welder only. 12. All the required refractory materials, SS anchors, SS retainer plates and cera wool will be supplied by NLCIL at free of cost at our stores and firm has to arrange for conveyance of materials from BTPS store/site store. 13. The refractory dry out is under the firm's scope. The firm has to arrange necessary oil burners, blowers, oil pump, oil storage tanks, line for carrying out the oil and other accessories etc required for refractory dry out. 14. The work spot shall be kept clean, free from the rubbish and discarded material. All such discarded materials and waste shall be removed then and there by the firm at his own cost as per NLCIL instructions. Refractory Dry out Procedure & Scope for 2X 125 MW CFBC Boiler at NLC India Ltd., Barsingsar. Contractor’s Scope. 1. All the required blowers, thermocouples, compensating cable, oil pumping unit, day tank and temperature recorder at two locations etc. 2. Required pipe line for Oil. 3. Oil supply will be provided by NLC at one point. Contractor should arrange pipe line from that point to oil tank. All required materials, manpower etc under contractor’s scope. 4. Electrical connection for burner/blower/others as required will be provided by NLC at one point. Cable & other accessories & tools are to be arranged by contractor at his cost. 5. Required technicians to carry out the dry out job. 6. Traveling expenditure & local conveyance. 7. Required PPE. 8. High velocity Burners as per the standard procedure involving 5 Nos of burners (2 Nos in Cyclones , 2 Nos in Loop seal/seal pot & 1 in combustor or as per the direction of the corporation officers). 9. Additional burners (minimum 2 no.), blowers (minimum 2 no.) & other spares as required are to be kept ready at site during dryout. 10. Required safety measures NLC’s Scope. 1. Required quantity of LD oil for the dry out process. 2. Compressed air required for oil atomization in burners. 3. Electric connections to the equipment like burners, blowers, temperature scanner and pumping unit. 4. Lighting in all locations. 5. Fire engines & extinguishers during dry out process. Refractory Dry out Procedure Ø The castables shall be allowed to air dry at ambient temp for 24 Hrs minimum after completion of lining, ie the time between completion of refractory installation and start up of dry out must be minimum 1 day. This is a separate activity. Ø Raise the ambient temperature to 110 Deg C @20 Deg C / hour. Hold at 110 Deg C for 24 hours. Ø Raise the temperature 110 Deg C to 250 Deg C @25 Deg C / hour. Hold at 250 Deg C for 12 hours. Ø Raise the temperature 250 Deg C to 400 Deg C @25 Deg C / hour. Hold at 400 Deg C for 12 hours. Ø Decrease the temperature @50 Deg C / hour up to 150 Deg C and put off the burner. Preparation for Installation Surface Preparation Clean the shell, before application of refractory. The surface must be free from grease, oil, dust and any other foreign materials. Wrap the tip of anchors with insulation tape or provide plastic cap for expansion allowance. Shuttering Preparation (for Dense & Insulation Castable) Make a plan for casting as per site condition (shuttering details panel length from which area casting has to be started and etc) Prepare shuttering as per casting plan. Decide the panel size, if not already decided. Plan staggered panels as far as possible to ensure staggered joints with respect to hot face and backup layer. Shuttering materials can be either wooden or metal. But ensure shuttering has to be strong enough to bear the load of material; vibration, ramming and etc., if required give further supports. Apply grease/ oil at shuttering surface for easy removal and prevention of water absorption. Ensure number of shuttering available at site to avoid delay for want of shuttering required during casting. Shuttering Preparation (in case of roof and any complicated design for Refractory Castable) Make a plan for installation of refractory castable as per site condition (shuttering details, panel length, from which area lining has to be start and etc.) Prepare shuttering as per installation plan. In case of Roof Casting, first install dense castable and then fill Insulating Castable (manually by tamping). This will ensure good compaction in the roof area. Shuttering materials can be either wooden or metal. But ensure shuttering has to be stronger enough to bear the load of material, ramming pressure during application, etc., if required provide further supports. Provides holes of Æ 5mm, for making vent holes at an interval @ 250mm. Apply one coat of grease /oil at shuttering surface for easy removal and prevention of water absorption. Ensure number of shuttering available at site to avoid delay for want of shuttering. Fixing of Water Percentage for Castables Take 100 kg of one batch of material in a pan mixer. Dry mix for 1 minute. Add water as per manufacture specification data sheet. Mix of 3-5 minutes for conventional castables and mix for 5-7 minutes for low cement castables. Check for workability by ‘ball in hand’ consistency method. If required increase water percentage step by step till satisfactory mix is obtained. The extent of water to be added will be decided by NLC Site Engineer during application as per the working consistency, since the same varies for difference castable and for different site depending on the climatic condition. Shuttering Fixing Details For Dense and Insulating Castable (if installed manually) Ensure the proper shuttering available at size as per the casting plan with required tools & tackles and supports for fixing the supports. Ensure the required numbers of shuttering and stopper plate at site to avoid stoppage of work due to want of shuttering/stopper plate. Ensure separate manpower for fixing the shuttering, while many fronts are available for casting. Apply a coat of grease/oil over the formwork. Check it before placement. Fix the shuttering as per required thickness. This can be maintained by fixing small stopper/ wedge at the top of the shuttering. Check the vertically by plumb that will ensure the uniform thickness through the panel. Installation of Insulating Castables Mixing of Castables Clean the mixer thoroughly. Charge known quantity of castable in the mixer. Mix dry for about one minute. Add specified quantity of water. Mix as per predetermined schedule. Discharge the mixed material from the pan mixer. Insulating castable can also be mixed manually in case quantity is small or adequate number of manpower is available to carry out manual mixing. Casting The mixed castable should be cast as early as possible. Fill the material uniformly in the shuttering and castable levelling should be uniform through out the panel. In slope area, the insulation castable can be installed by providing only side stopper plates. This will give good compaction in slope area. Ensure proper filling of material in the shuttering. Check the surface for proper setting. Remove shuttering carefully after material has set. Removal of Shuttering Check and ensure proper setting of castable. Remove all the supports provided for fixing the shuttering/ stopper plate one by one. Don’t apply heavy force for removing the supports. If heavy force is applied for removing the supports it will disturb the castables. Remove the shuttering slowly. Inspection Check for honeycomb, rat hole, segregation, lamination, etc. mark the area be repaired. If repairs area is very less, carry out necessary repairs work by removing the loose material and filling it with new fresh material and compact with rodding. If the repair area is more, dismantle the repair area and recast. Make the casting installation details. Natural Curing Allow air-drying for minimum 8 hours after casting. Total Quantity :
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