Transcript Incineration

Thermal Treatment/Disposal:
Incineration
Chapter 12
Activity
• Why use incineration?
• What are the drawbacks?
Regulations
• Historical perspective
• HW incinerators vs. cement kilns and light
aggregate kilns and industrial boilers and
furnaces
General Schematic
Types of Incinerators
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Rotary kiln
Fixed hearth
Liquid injection
Cement and lime kilns
Fluidized bed
Boiler systems
Oxygen enriched
Infrared
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Fume
Multiple chamber
Multiple hearth
Cyclonic
Auger combustor
Two-stage (starved
air)
• Catalytic
• Molten salt
Other Thermal Processes
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Plasma arc pyrolysis
Microwave discharge
Advanced electrical reactor
In situ vitrification
Wet air oxidation
Supercritical water oxidation
Calcination
Thermal desorption
Classifications of Incinerators
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Grate
Open “rack”
Stationary or moving
Air circulation
Large and irregular
wastes
Hearth
Solid “plate”
Variety of waste
Suspension
• Sand or alumina bed
fluidized with air
• Relatively uniform
feed size
Typical Process Flow Diagram
Waste
Storage
Pre-processing/blending
Incineration
Ash
Flue Gas
Stabilization
Landfill
Pollution
Control
Effluent
POTW
Combustion Requirements
3 T’s
+
Excess O2
Typical Excess Air Reactions
CHCl + O2 + N2  CO2 + H2O + HCl +
O2 + N2 + heat
Flue Gas Quench
• Cool to:
– 500 - 700oF for spray dryer
– 180oF for low-temperature equipment
• Air or water
• Concurrent or counter-current flow
Air Pollution Control
• Pollution:
– Particulates (including 10 priority metals)
– Acid gases
• Systems
– Wet
– Dry
Trial Burn
Test incinerator
– Principal organic hazardous constituents
(POHCs) destruction and removal
efficiencies (DREs)
– HCl
– Particulates
– CO
– Metals
– Dioxin and furans
POHC DRE
At least 99.99% on all selected POHCs
during trial burn
Win  Wout
DRE 
100
Win
HCl Emissions
Emission no greater than larger of
4 lb/h or 1% of HCl in stack gas
Particulate Emissions
At most 0.08 grains/dscf corrected to 7% O2
or
180 mg/dscm corrected to 7% O2
Emissions Example
Example 12-2 (p. 746)
Does incinerator performance meet
requirements?
CO Emissions
100 ppm by volume as a 60-minute rolling
average corrected to 7% O2 on a dry basis
CO and Particulate Example
Example 12-11 (p. 804)
14
Pc  Pm
21 Ydry
Ydry
Ywet

1 w
Combustion Efficiency
At least 99.99%
CE 
CCO2
CCO2  CCO
100
Dioxin and Furan Emissions
0.4 ng/dscm
or
0.0001%
PCBs
At least 99.9999% DRE for liquid
Dwell time of 2 s at 1200  100 oC and 3% EA in stack
gas
OR
Dwell time of 1.5 s at 1600  100 oC and 2% EA in stack
gas
Design
Example 12-7 (p. 765)