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8/11/2019 Group 2- Wet Based Bottom Ash__
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Presented By: Group 2
Date: 2/9/2013
Parth Jayesh Gohel
V. Anirudh Reddy
Yashwardhan Joshi
Anne Kranthi
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Types of Ash
Ash : The residue after the incineration
of coal.
Types of Coal in a Power Plant :
a) Bottom Ash : The ash is that is
directly collected from the
bottom of the boiler.
b) Fly Ash :The ash that leaves theboiler from the top of the boiler
and goes through the ESP to
Silos.
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Bottom Ash Handling System
Bottom Ash is only 20% of the total ash.
Bottom Ash-Handling System : ->
i. Wet Handling System
a. Jet Pump Disposal System
b. Submerged Conveyor systems
Scraper Chain conveying System
Belt Conveying System
Screw Conveying System
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Jet Pump Disposal System
Also known as W-shaped System
Have water impounded system and jetpumps for intermittent removal
The bottom ash falls into a W-type waterfilled ash storage hopper
The storage ash is removed by means ofjet pumps and transported in slurrypipelines to ash slurry sump for its further
disposal. Water consumption is very high, almost 3
times that of ash removed.
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The complete system
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Hoppers (W-shaped)
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Scraper Chain Conveying System
Belt conveyors are used to dispose the bottom ashfrom scraper chain conveyor to bottom ash silo.
Employ continuously operating on submerged beltconveyor running below boiler furnace.
SSC system receives hot clinker, slag and ash fallingfrom the boiler , through a transition chute to waterfilled trough.
The trough containing the conveyor is filled withwater for quenching of bottom ash.
Bottom ash discharged onto scraper chain conveyor,
where it is fed to grinder that crushes it to 25mmsize.
The crushed bottom ash is conveyed to bottom ashsilo using belt conveyors.
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Scraper Chain Conveying System
Clinkers from
Boilers
Transition
Chute
ScraperChain
Conveyer
CrusherBelt
conveyorBottom Ash
Silo
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Components in the scraper
chain system1. Scraper Chain Conveyor
Also called Drop
Forged chain. The attachments, here waterfilled troughs, are welded on to the chainlinks.
2. Clinker Crusher
The large sized ashclinkers are crushed using these crushers.The clinkers get trapped between the rotating
jaws of the crushers and get crushed to arequired size.
3. Dewatering Tanks
The sludge from thecrushers come to the dewatering tank, wherethe water is separated and used again. Thereare screens present for the same.
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Scraper Chain Conveyor
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Clinker Crusher
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Dewatering System
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Submerged Belt Conveying
System
1. It is the same as chain scrapper, but the
only difference being that here we use
a belt rather than a chain scrapper and
the belt must of a good quality towithstand the temperatures.
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Screw Conveying System
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Combined System
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Dry vs. Wet
Dry Systems are environment friendlyand economically beneficial.
Wet system disadvantages:
Huge water consumptionHigh maintenance cost due to corrosion
Environmental issues due to leakage ofcontaminated water
Loss of boiler efficiency,
Negative effects on boiler operation due to thelow reliability and poor maintainability of wetsystems.
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Gherh w
We hw h
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Bnmsrt
Ethjst h4
Nas hwt h4
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Thank You
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hthrth thwt
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