INCINERATION OF MSW

Type of Incinerator

Technology advancement

Waste-to-Energy-Process

Flue Gas Pollutant

Definition

Advance Thermal Treatment (ATT)


  • exclude incineration with considered mature
  • principally pyrolysis & gasification
    -recover heat, electricity or fuel

waste treatment process that invovle combustion of organic substances contained in waste material

Modern Incinerator



  • equipped with pollution improvement system to clean the flue gas and toxicant

Incineration reduce mass waste from 95 to 96 percent

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4) Fixed Grate


  • older version for grate
  • lined is brick while ash pit is made of metal
  • has opening at top, side of grate is left open

Fluidized Bed


  • air blown in high speed over sand bed
  • waste required segregation and size reduction
  • dees rate is small to ensure efficiency

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Special Incineration


  • furniture factory sawdust incinerators need attention since it need to handle resin and flammable substances

2) Burn Barrel


  • more controlled form of private waste incineration
  • containburning material inside metal barrel

Moving Grate


  • capable for haauling waste from combustion chamber to give complete combustion

1) Burn Pile


  • also known burn pit is simplest and earliest waste disposal
  • consist of a mound of combustible materials pile on ground and set on fire
  • can spread uncontrolled filre

3) Rotary Kiln


  • used by municipalities and large industries
  • in primary chaber, solid turm to gas by volatilization, destructive distillation and partial combustion reaction
  • second chambest is to complete the gas phase combustion reaction

1- waste is poured in grate with help of crane
2- waste move toward ash pit. waste is treated and water is use to wash out ash
3- air flown through waste and it function for cooling grate
4- air is blown another time and faster than previous
5- This helps in complete burning of flue gas with introduction of turmoil for better mixing and excess oxygen

Waste –to – Energy Facilities

Air Pollution Control

Pyrolysis

SOx

Particulate matter

NOx

CO

NOx form from


  • reaction between oxygen and nitrogen at high temperature
  • reaction between nitrogen and oxygen form fuel
  • combustion and in large quantity
  • effect health problem for people have asthma and bronchitis
  • should keep minimum
  • serious health can be effected due to inhalation particle
  • incinerator should equipped control devise such as cyclone, settling chamber
  • cause by inefficient combustion
  • high CO can give poor performance and health effect such as headaches and nausea

good combustion practices

emission control devices

Remove certain waste components

Emission Control Device


  • Baghouses
  • Acid Gas scrubber
  • Electrostatic Precipitator

Advantages


  • Volume and weight reduces incineration can be dine in generation site
    -air discharge can be controlled
  • ash residue is sterile, inert

Diasadvantages


  • Some material require supplemental fuel
  • Public disapproval
  • High capital cot

Gasification

  • thermal decomposition through indirect heat in absence of oxygen
  • when occur in water it called hydrous pyrolysis
  • Long chain C,H,O compound breakdown into smaller molecules in form of gas,condensable vapour and solid charcoal

TYPE

Slow types (take several hours to complete)
- bio- char
-as coal replacement in cerain combustion

  • used in agriculture for soil amendment
  • highly absorbent

Fast type

  • takes 2 second
  • temperature between 300-500C
  • commonly yield 60% bio-oil

Bio oil


  • not suitable for direct use in standard internal combustion engines
  • can be upgraded to special engine fuel (gasification) - syngas - biodiesel

Syn gas

  • short for synthetic gas
  • derive from pyrolysis
  • made up of carbon monoxide and hydrogen
  • involve reaction of carbonecous feedstock with an oxygen- containin reagent (CO2, air, steam)
  • temp: 800C

Application : Generator, Hydrogen Membrane separator, gas turbine


Type Gasifier: Fluidized Bed, Multiple Hearth, Rotary Kiln

Advantages :

  • syngas from gasification is easier to handle
    • can be design for small-medium scale

Disadvantages:

  • toxic an potential explosive
  • costly

Advantages:

  • can be performed at small scale
  • wide range biomass feedstock can be used

Disadvantages:

  • very dependent on moisture content
  • process can produce dust at lower water level