Waste Incineration The British Experience Mass burning and Fluidised Bed Technology

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CIWM Conference June 2006
Tracking Micropollutants from Cradle to Grave
J Swithenbank, V Sharifi, D Poole, YB Yang, C Ryu
et al SUWIC Sheffield University Waste
Incineration Centre
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Presentation Overview

• National Air Standards
• Pollutant dynamics UK trends
• Highlight Selected pollutants
• Conclusions

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Air Pollution UK Consequences

• About 20,000 people are killed by traffic
  pollution every year.
• About 8000 people are dying yearly because of
  particulate matter alone.
• Life expectancy is increased by 1.5 to 3.5 days
  if
• 1 µm g/m3 reduction of PM2.5 is achieved.
• The Guardian, 2003
• COMEAP (1998)

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Incinerators meet tighter regulations for NOx
SOx etc than most other combustion systems,but
there is- A UK public perception problem

• E.g. Dioxins from incinerators are 1 of the UK
  total. Bonfire night on November 5th creates
  more dioxins!

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UK Legislation

• Power Station Emissions Covered by the LCPD
  (Large Combustion Plants Directive).
• Waste Incinerator Emissions Covered by the WID
  (Waste Incineration Directive, 2000/76/EC).
• Pollutants in the environment would increase if
  an incinerator were to close since the emissions
  from the replacement power station would be
  greater!
• The Goal posts continue to move.

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Example of Pollutant Dynamics and Health Effect
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• SUWIC Programme Strategic Overview
• Pollutants from combustion systems
• Power stations
• Vehicles
• Cement kilns
• Incinerators
• Micro-pollutants
• Heavy Metal Emission Measurements
• Dioxins/Furans/PCBs

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CO in the UK (2001)
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CO Spatial Distribution in the UK (2001)
From Dore et al. (2003)
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NOx Spatial Distribution in the UK (2001)
From Dore et al. (2003)
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Introduction What Are Dioxins?

• 210 congeners 75 dioxins and 135 furans
• 17 toxic congeners with Cl atoms in 2,3,7,8
  positions
• Toxicity of congeners expressed in TEFs and TEQs
• 2,3,7,8-TCDD most toxic congener with TEF of 1

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SUWICs Research in Dioxin REVIEW
? Dioxins/Furans - Solvent extraction unit
- Ion Trap GC-MS/MS (Varian Ltd.
Dionex Ltd.) - Immuno-assay facilities -
Dioxin Research Network
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Analytical Sampling
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Analytical Sampling
Bottom ash
Superheater residue
Fabric filter ash
Economiser ash
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Modelling Approach
Formation in Boiler System
Adsorption in Fabric Filters
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Modelling Review De Novo Synthesis

• Dioxins generated at moderate temperatures from
  particulate organic carbon in fly ash by
  gas-solid reactions with O2 and halides.
• Influencing Factors
• Temperature 250oC 400oC
• Carbon of certain degenerated graphitic structure
  is primary source concentration in ash
• O2 essential
• Cu (II) ions concentration in ash, strong
  catalytic effect

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Modelling Formation Rate
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Modelling Formation Rate
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The total concentration of PCDD/F formed
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Modelling Formation Rate for 13 Incinerators
before clean-up filter
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PCDD/F removal efficiency in fabric filters
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Modelling Removal Rate
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Comparison of Predicted vs measured PCDD/F for 11
Incinerators
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Why 850 deg C for 2 seconds ? It is neither
necessary nor very relevant
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PCDD/F vs residence time
TAMARA data
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The Dioxin Research Network www.sheffield.ac.uk/S
UWIC/ - A valuable source of data
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Fire Smoke is Largely Organic Oils

• Landfill fire smoke at Tequila, Mexico

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Particulate Matter

• Source apportionment is difficult due to
• 1. Contribution from many different sources.
• 2. Emissions from some potentially large
  sources are not well established.
• 3. Variation in atmospheric lifetimes and range
  of travel.

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One Source of Particulates mass burn of
waste/biomass on a moving bed
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Recent Bed Modelling Research Progress

• SUWIC has developed a numerical model of
  combustion in the incinerator bed FLIC
• Flow channelling, radiation, conduction.

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Particle random packing theorychannel formation
and gas flow
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Simulation of gas velocity (m/s) by channel
formation in a packed bed
Grate causes initial uniform flow
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Particle size emitted along the bed.
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Emitted Particle Composition along bed length
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DiagnosticsMeasurement of Heavy Metals in
Gases,Liquidsand Solids
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On the move
SUWIC Mini-Lab leaves Spectro factory, Kleve,
Germany. 7 February 2002
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Heavy Metals Continuous Analysis Transportable
Mini-Lab
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Heavy Metal Measurement
Inductively Coupled Argon Plasma (ICAP) gt
6000K
To Continuous Analysis Spectrometer. Linear over
6 decades
70 Elements Emission Spectrum
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(No Transcript)
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Waste incinerator plant, showing the sampling
locations
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Sodium concentrations for a 4.5 Hour Period,
measured on the 589.592 nm emission line (NB Gaps
in this, and subsequent emission measurements are
due to cleaning of the sample probe to remove
deposited ash).
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Comparison of sodium and potassium concentrations
for a 4.5 hour period, showing strong correlation
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Lead concentrations for a 4.5 hour period
measured on the 405.778 nm emission line before
the gas cleaning system.
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24-Hour Emission Profile for Lead after the gas
cleaning system. (The large spikes correspond to
the injection of standard calibration samples
into the instrument)
0.01mg/m3
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Cadmium concentrations for a 4.5 hour period,
measured on the 226.503nm wavelength
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Mercury concentrations for a 6 hour period
measured on the 253.653 nm wavelength before the
gas cleaning system.
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Conclusions

• Pollution levels vary significantly with time and
  place, hence pollutant modelling and health
  impact analysis must take account of the
  historical record and anticipated future
  developments.
• Dioxin emission levels are well controlled and
  mechanisms are largely understood.
• Advanced numerical modelling of the bed and
  freeboard show particulate emissions vary
  significantly along the incinerator bed.
• Our unique mobile ICP/OES instrumentation gives
  continuous measurement of more than 50 species
  including all the heavy metals.
• Sodium and potassium concentrations are closely
  correlated. Observed fluctuations in lead,
  cadmium and mercury are due to changes in plant
  feed.
• New results from dynamic measurements before and
  after the flue gas clean-up confirm excellent
  process efficiency.
• Proper facilities for battery disposal are
  urgently needed in the UK
• Engineering progress has succeeded in ensuring
  that Practically all pollutants born within an
  incinerator reach their grave within the plant.

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The End