2.8.17 AHP- Fluidising Air Blowers

2.8.17               Fluidising Air Blowers

 

                        Air blowers shall be designed for continuous operation with high efficiency to satisfy the system require­ments. Bidder shall furnish proper justification for selection of capacities of the blowers for various duties. 50 degree C air temperature and 100% RH shall be considered for design of capacity of air blowers.

 

                        The design shall incorporate every reasonable precau­tion for the safety of all operation and maintenance personnel.  Each blower unit should have all moving parts protected by a guard. The blowers shall be oil lubricated and water/air cooled.

 

                        The Blowers shall be constant volume/positive displace­ment type and each blower shall be provided  with suction filters, pressure relief valves with the corre­sponding vent pipe work, which shall be ducted to a safe discharge outlet, necessary isolating and non-return valves, inlet and/or outlet silencer so that blower unit can comply with the noise level require­ments.

 

                        a)         For buffer/surge hoppers, bidder shall provide a unit wise arrangement i.e. the fluidizing air for each unit shall each be supplied from a separate set of blowers of 2×100% capacity each.

 

                        b)         Each storage silos shall be provided with a 100% capacity silo aeration blowers with a common standby for all the silos.

                         

 

                        Necessary heating arrangement with a suitable bypass shall be provided at the discharge of the blowers to raise the temperature of aeration air to a temperature at least 160°C. Schemes shall also include for thermal insulation of all air pipe work from the blower outlet to the point of contact of fly ash.

 

                        All air blowers and their drives provided under this contract shall be completely interchangeable.

 

2.8.17.1            Drive Motor

 

                        Drive motor shall be connected to the Air blowers preferably directly.

 

                        The continuous motor rating (at 50°C ambient) shall be at least fifteen percent (15%) above the maximum load demand of the blower in the entire operating range to take care of system frequency variation total maximum load demand shall include air compression power plus any power consumed in auxiliaries like cooling fan etc. and transmission system losses, if any.

 

2.8.17.2            Instruments

 

                        Each silo aeration blower shall be provided with following instruments as a minimum.

 

                        (a)        Pressure gauge at the blower outlet                                  :           1 No.

 

                        (b)        Pressure gauge at the inter cooler                                    :           1 No.

 

                        (c)        Pressure switch at the blower outlet                                 :           1 No.

 

                        (d)        Pressure switch at the inter cooler                                   :           1 No.

 

                        (e)        Temperature gauge at the outlet

                                    (after air heater)                                                             :           1 No.

 

                        (f)        Temperature switch at the outlet

                                    (after air heater)                                                             :           1 No.

 

                        (g)        Pressure gauge at the equipment

                                    cooling water inlet                                                          :           1 No.

 

                        (h)        Pressure switch or flow switch at

                                    the equipment cooling water inlet                                    :           1 No.

 

                        The bidder shall include any other instrument required to make the system safe, efficient and reliable.                                                                 

 

The material of construction shall be as follows:

 

Casing	Cast Iron
Shaft	EN-8
Rotors	Cast Iron
All interconnected Piping	Galvanised steel as per IS:1239, heavy grade.  (All piping handling hot air shall be insulated to limit the surface temp. to 60°C)

 

 

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