INCINERATION

Define as:

Control process for burning solid, liquid and gaseous combustible

wastes to gases and residue containing non-combustible

material.

is any facility used wholly or in part for the controlled combustion of municipal wastes and other waste.

waste materials are treated at incinerator plants through the controlled application of that converts waste feed by high temperature oxidation to gaseous material.

during combustion the moisture is vapourised while the combustible waste is also vapourised and oxidised.

final products are CO2, water vapour, ash, and non-combustible or residue.

Objectives of thermal treatment

volume reduction

reduces 90% MSW

reduces 70% of weight

life span of a landfill could be longer

Waste stabilisation

outputs from the incinerator are ash, flue gas and combustible residue.

the output generally inert and more stable when landfill.

Waste to energy conversion

reduce the usage of fossil and fuel

Conversion of natural resources.

Sanitisation of waste

high temperature (800 – 11000C)

outlet 210 -230oC

kill all the pathogen – important in the clinical/hospital waste.

categories of incinerator

Three categories:

mass burning

Selected burning

source separated materials

The Incineration Process

Four types of incinerator

Multiple chamber incinerator

Non-heat utilization incinerator

Fluidised bed incinerator

Rotary kiln combustor

Multiple chamber incinerator

the simplest incinerator

combustion proceeds in two sage

combustion in the ignition chamber

gaseous phase combustion in the secondary combustion chamber.

Non-heat utilisation incinerator

similar with multiple chamber incinerator except the waste to energy process is not included

accommodate up to 1,000 tonnes/day.

capacity of storage pit 16 to 36 hrs of refuse intake

furnaces used are vertical circular, multicell rectangular or rotary kiln.

Fluidised bed incinerator

uses a vertical furnace as alternate design

develop and commonly used in Japan

the combustion chamber contains a fluidised bed

advantage of this system is less mechanical problems

FBI has a maximum capacity 350 tonnes/day

more efficient in burning and flue gas volume is smaller.

start up time is much smaller – 5 min

Rotary kiln combustor

rotary kiln is circular, inclined, cylindrical

slow revolving combustion chamber

waste is rotated slowly

perforation along the kiln allow O2 be pumped – efficient burning

energy transfer by three method

radiation from the refractory inner space surface transfer energy to all surface in the kiln

by convection from the hot combustion gasses to the feed material

the hot refractory surface continuously comes into contact with the underside of the bed

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