Fly ash is one of the residues generated in combustion, and

comprises the fine particles that rise with the flue gases. Fly ash is

generally captured by electrostatic precipitators or other particle

filtration equipment. All fly ash includes substantial amounts of

silicon dioxide(SiO2) (both amorphous and crystalline) and calcium

oxide(CaO).

In the past, fly ash was generally released into the atmosphere, but

pollution control equipment mandated in recent decades now require

that it be captured prior to release.

Size range – from 0.5 µm to 100 µm

There are two types of Fly Ash Removal System

Use of Hydro Sluicing Removal System gradually

decreasing due to :-

Huge water requirement.

Huge Storage Area (Ash Pond) required.

Ash can’t be used.

Pneumatic Conveying System

Ash

Fly Ash

Pressure Vacuum

Bottom Ash

Fly Ash from various hoppers is evacuated using a Pneumatic

Vacuum Conveying System in lean phase up to an

intermediate hopper or Silo. Hydraulic exhausters or vacuum

pump creates vacuum.

MULTI HOPPER SHORT DISTANCE APPLICATION

LESS HEADROOM BELOW HOPPER

HIGHER VELOCITY & POWER CONSUMPTION

ESP (COARSE/FINE ASH) HOPPER

DUCT

BAG FILTER

FLY ASH SILO

UNLOADER/DRY UNLOADING CHUTE

CLOSE/OPEN TRUCK

HIGH POWER CONSUMPTION

LONG DISTANCE CONVEYING

HIGH VELOCITY( STARTING VEL.-12 to 19 m/sec), HIGH WEAR

APPLICATION IN TRANSPORT OF MATERIAL WHICH ARE

NON FLUIDISED AND NON-CONDUCIVE FOR FLOW IN

DESIGN RANGE

Fly ash is conveyed from one point to another point using

Pneumatic Pressure Conveying System. Ash is conveyed

in suspension in the pipe. Positive displacement blowers like

twin lobe blowers and compressors are used.

ESP (COARSE/FINE ASH) HOPPER

PRESSURE VESSEL

DUCT

FLY ASH SILO

UNLOADER/DRY UNLOADING CHUTE

CLOSE/OPEN TRUCK

Indian coal presents high ash content generally

which tends to be inconsistent. Design of the system

has to adequately cover anticipated variations and be

capable of handling the worst scenario.

System has to be environmentally friendly.

System has to be reliable with least maintenance

problems.

System has to be energy efficient.

Design and Reliability of Pneumatic Conveyer

Depends on:

The accuracy of the input parameters and the degree in which they reflect the reality.

The accuracy of the performance data of the pneumatic installation components.

The completeness of the theory on which the calculation algorithm is built.

The degree of approximations in the calculation algorithm.

Cement Plant.Ash Brick

Land & Mine

Filling

&

High-way

Constructions

When Dry or Semi-dry Fly Ash collection and

disposal is desired, Silos of RCC OR Steel

construction collect the Ash from Conveying

System either directly or through Dust

Separator. Silos are provided with fluidizing

arrangement for easy discharge of Ash through

the bottom outlets.

Ash Unloading System options from silo are :-

a Complete Dry Unloading into enclosed tankers / Wagons

a Semi-Dry unloading to open Trucks / Wagons

a Dry / Semi-Dry unloading to Belt Conveyor Systems

a Wet unloading through Feeder Ejectors for Ash disposal in slurry form.

Capacity= 1500 TStorage Capacity= 14hrs

A Blower is used in Conveyingsystem to give the hot air to theSilo, Hopper and make the airflow in a controlled way.

A vacuum pump is a device thatremoves gas molecules from a sealedvolume in order to leave behind apartial vacuum