group 2- wet based bottom ash__

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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Thank You


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group 2- wet based bottom ash__

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