Dry Ash system : 500 MW
Dry Ash system : 500 MW
- Ash is oxidised form of the mineral matters present in coal
- Typical ash composition : SiO2, Al2O3, Fe2O3, CaO, MgO etc
- Coal with more SiO2 & Al2O3, Ash MP > 1400ºC
- Coal with more Fe2O3, CaO & MgO, Ash MP < 1100ºC
- Ash content of Indian coal used in power station is about 30 to 40 %.
- A typical 2000 MW station produce around 9000T to 12000T of ash per day
- FA is collected from Air heater hopper, Eco hopper and ESP hopper
- In Flushing apparatus system ash is allowed to fall in flushing apparatus under gravitation.
- Water jet in flushing apparatus carries away the ash to FA trench
- High pressure jets further carries it to FA sump.
- In Dry Ash Mode: Vacuum pumps are used to convey ash from the ESP hoppers to Bag Filter and CTT
- In Bag Filter Dry ash is separated out from the air
- Through Transfer Hopper ash is transferred to Buffer Hopper
- Blower are connected to the bottom of buffer hopper for fluidized air supply
- From buffer hopper, it is transferred to Transporter.
- From Transporter, Dry ash is conveyed through Pipe lines (Pneumatic Conveying). For pass A & B the line is AB similarly for pass C & D the line is CD
- Modes of conveying: a) Dilute phase: If the material is conveyed in suspension in the air through the pipeline it is referred to as dilute phase conveying.b) Dense phase: If the material is conveyed at low velocity in a non suspension mode, through all or part of the pipeline, it is referred to as dense phase conveying.
- In dense phase conveying two modes of flow are recognized.
- Moving Bed Flow: Moving bed flow is only possible in a conventional conveying system if the material to be conveyed has good air retention characteristics.
- Plug Type Flow: Plug type flow is only in a conventional conveying system if the material has good permeability. This type of flow is typically limited to the materials that are essentially mono-sized, since these allow the air to pass readily through the interstices between the particles.
- Vacuum pump is use to convey the Fly Ash from ESP hoppers to the CTT (for wet system) and bag filter (for Dry system).
- Type of pump :Water Ring Vacuum Pump
- Total No. of pumps : 8 Nos.
- Capacity : 4200M3/Hr
- Shut-off Vacuum : 500 mm of Hg
- Machine speed : 460 RPM
- Electric Motor : 90 Kw at 1440 RPM
- Seal water req. : 65 LPM
- Seal water pressure : 1 Kg/cm2
- Seal water Temp. : 300C
- TAC is used to convey the Ash from Transporter to Ash SILO
- No. of compressor- 12
- Type- Screw Type Compressor
- FAD-2360M3/Hr. (AT 50 C & 100% RH), Head-50 WWC
- Motor HP/KW-362/270
- Speed Of Motor-3000 RPM,3.3 KV
- Oil Sump Capacity-250 Ltrs.
- Dry Fly Ash Silo is used to store Dry Fly Ash And to upload the Bulker
- Total No. of Ash Silo – 3 Nos
- Capacity :- 1500MT/2000M3 of each
- Average Supply of Dry Ash on Daily Basis – 10 Bulker
- Capacity of Bulker – 40MT
- SILO Aeration Blowers:- Used to provide hot air to the SILO
- Total No. of Blowers : 3 Nos.(2W/1S)
- Air Flow : 850M3/Hr (FAD)
- Pressure : 0.45 Bar
- Ash Conditioner Booster Water Pumps:-Used for Ash Conditioning
- total No. pumps : 2 Nos.(1W/1S)
- Water Flow Rate : 23M3/Hr
- Discharge Pressure: 5 Kg/cm2
- Wash water Pumps: For Floor washing
- Total No. pumps : 2 Nos.(1W/1S)
- Water Flow Rate : 50M3/Hr
- Discharge Pressure: 1.5 Kg/cm2
- Drain pumps: To drain the water
- Total No. pumps : 2 Nos.(1W/1S)
- Water Flow Rate : 80M3/Hr
- Discharge Pressure: 3.5 Kg/cm2
- Major usage of ash
- Fly ash bricks / blocks
- Cellular concrete products
- Light weight aggregates
- Concrete and mortar
- In manufacture of cement
- In manufacture of asbestos products
- Road construction
- Embankment/back fills/land development
- Controlled low strength material (CLSM)
- In agriculture
- Mine filling
- Production of fertilizer
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