10 incineration hazardous

8/3/2019 10 Incineration Hazardous

1/36

1

Waste Recycling and CompostingLVA 813.359

Institute of Waste Management, BOKU - University of Natural

Resources and Applied Life Sciences ViennaHead of Institute: Peter Lechner

4_incineration_hazardous.ppt

Stefan Salhofer, Erwin Binner, Roland Linzner

Waste Incineration andHazardous Waste Management

SS 2009Waste Recycling & Composting 2

Thermal treatment of wastes - Contents

Fundamentals

Types of incinerators

Reduction of pollutants

Residues

Energy recovery


2/36

2


Thermal treatment of wastes

Fundamentals


Thermal treatment - purposes

Reducing the amount of waste which has to be

landfilled

Destruction of organic substances

Substitution of fossil fuels (reduction of CO2-

emissions, conservation of resources)

complete disinfection (e.g. of infectious waste)


3/36

3


Operating modes

Oxidizing Systems (grate types, rotary kiln andfluidized bed) require sufficient oxygen, they mostlyoperate with excess oxygen.

Pyrolysis is a process for de-gassing and exhaustwithout oxygen and with a subsequent combustion ofthe gases from the pyrolytic chamber.

Processes which combine different procedures, suchas the Thermoselect * process, are currently in an

experimental stage (1 facility in Europe, 6 in Japan)They have the advantage, that the residues from thisprocess do not require an additional treatment.

* http://www.thermoselect.com/index.cfm


The combustion process

Drying

De-gassing

Exhaust

Combustion

Flue gas + residues

Water vaporises

volatile compounds volatilise

Primary air hypo-stoichiometric

organic substances CO, H2, CxHy

CO + 0,5O2 CO2,

H2 + 0,5O2 H2O,

CxHy + O2 CO2 + H2O

Control parameter: CO/CO2 < 0,002

100C

250C

5-600C

800-1200C


4/36

4


Burnout

EU-Directive (2000):

Incineration plants shall be operated in order to

achieve a level of incineration such that the slag

and bottom ashes Total Organic Carbon (TOC)

content is less than 3 % or their loss on ignition

is less than 5 % of the dry weight of the

material. If necessary appropriate techniques of

waste pretreatment shall be used.

DIRECTIVE 2000/76/EC OF THE EUROPEAN PARLIAMENT AND OF

THE COUNCIL of 4 December 2000 on the incineration of waste


Thermal treatment of waste



5/36

5



Grate incinerators

Fluidised bed reactor

Rotary kilns

Pyrolysis

Co-incineration


Grate incinerators

Oldest and most developed type of incinerator for the

combustion of household waste; to some extent co-

combustion of dewatered or dried sewage sludge

Waste isWaste is discharged from the storage bunker into the

feeding chute by an overhead crane.

It is fed into the grate system by a hydraulic ramp orsystem by a hydraulic ramp or

another conveying system.another conveying system.


6/36

6


Grate incinerator

Waste is conveyed through the incineration chamberby reciprocating or rolling grate sections and traversesthe different stages of the incineration (drying, de-gassing, exhaust and incineration). The conveyingvelocity can be controlled. The residence time (timebetween waste feeding and bottom ash discharge) isabout 3030 minutesminutes..

Purpose of incineration: oxidation of combustible

substances. This is checked by the loss of ignitionloss of ignition ofthe solid residues (slag and ash) and the compositionof the flue gas.

With modern incinerators, a loss of ignition (slag andash) between 1% and 3% are achieved.


Storage bunker


7/36

7


Overhead crane


Scheme: Grate

incinerator

Flue gas

Bottom ashPrimary air supply

Wood,

biomass

Drying

Decom-

positionIncineration

Burnt out

material, ash


8/36

8


Grate


Basic principle of the process:Basic principle of the process:

A bed of inert material (e.g. sand or ash) on a grate ordistribution bed is fluidised with air from below and heldin suspension.

The waste is continuously fed into the fluidised sandbed.

Because of the well mixed nature of the reactor,fluidised bed incineration systems have a uniformdistribution of temperatures and oxygen, which resultsin stable operation.

The temperature is generally between 800 and 950C.

Fluidized bed reactor


9/36

9


Fluidized bed reactor

ADVANTAGES:

less ash (splitting)

improved burnout due to smaller size of the solids and athorough mixing (equal distribution of material and heat)

less Nox, due to a lower temperature

CONDITIONS:

waste has to be crushed/ shredded to approx. < 150mm

ferrous materials and larger inert particles should be

sorted out

the performance of the incinerator can be controlled over

the feeding of the (waste) fuel (+ oil)


Stationary fluidized bed

EIPPCB 07/2005, p. 49


10/36

10


Circulating fluidized bed

EIPPCB 07/2005, p. 51


Rotary kiln

consists of a sloped refractory-lined cylinder which

rotates slowly on its longitudinal axis. Waste moves

horizontally as well as radially through the cylinder

(because of rotation and slope)

flue gasflue gas is burnt in an afterburner chamber (with itsis burnt in an afterburner chamber (with its

own burners to heat the flue gas)own burners to heat the flue gas)

one advantageadvantage is that large items can be fed as a

whole (e.g. barrels filled with solvents)


11/36

11


Wastes which can be typically treated in rotary kilnincinerators are

solid wastesolid waste: soil contaminated with oil, contaminatedbarrels and containers, cured plastic wastes, ...

pasty wastespasty wastes: residue from paint, residue from thecleaning of tanks, sludges from industry, residue from

grinding liquid wastesliquid wastes: waste oils with different water contents,solvents, tar, not cured plastic waste

Rotary kiln


Rotary kiln

A waste feedingB ash/ slag dischargeC flue gasD auxiliary fuelsE airF thermal radiation

1 shell of the rotary kiln2 refractory lining5 cooling air ventilator10 controllable drive11 water vapour zone

12 wastes13 combustible material14 ash/ slag


12/36

12


Pyrolysis

heating and degassing of wastes in the absence of oxygen

--> pyrolysis gas comprises CO and H2, but alsoharmful substances such as auch HCl, NH3, PAH etc.

CO and H2 can be recovered by synthesising methanol

(Schwarze Pumpe in Germany)

incineration of the pyrolysis gas (Schwel-Brenn-process of

Siemens)

Residue from pyrolysis: carbon (solid coke), not oxidised

metals



Reduction ofpollutants


13/36


14/36


15/36

15


Particulates are separated by using physical processes

Cyclones: are solely applied as pre-deduster. Theparticle-size of a part of the solids is too small, so thatthese cannot be separated by means of cyclons.

Electrostatic precipitator (electrostatic filter): particles arecharged by impressing a high voltage between 2electrodes and are precipitated on the collector plate.High efficiency (99% of particles precipitated); mostfrequently used technique in waste incineration plants

fabric filters: also called bag filters, are widely used, canalso be used following an electrostatic precipitator

Dust removal


Cyclone

Raw gas

Raw gas

Clean gas

discharge

tube


16/36

16


Electrostatic precipitator

Particulatematter

Re-precipitator ioniser collector airflow


Wet processes

Frequently two-stage scrubbers are used. At the firststage, the acidic pollutants HCl (hydrogen chloride)and HF (hydrogen fluoride) are absorbed by a liquid(mostly water) at a pH < 1, and are subsequently

accumulated by using limestone, lime milk or causticsoda as a neutralising agent.

At the second stage, SO2 (sulphur dioxide) is removedat a pH close to neutral or alkaline. The scrubbersolution contains the dissolved reaction products andrequires a complex recycling of water and sludge. Thefinal product is usually a filter cake with a high load ofpollutants (salt load), which has to be depositedunderground.

Chemical flue gas treatmentChemical flue gas treatment


17/36

17


Semi-wet processes (also: semi-dry processes)

the sorption agent is injected either as suspension orsolution into a spray reactor and is evaporated. Thereaction products generated are solid (salts) and need tobe deposited from the flue gas as dust in a subsequentstage, e.g. bag filter. No waste water is generated.

Dry processes

the adsorption agent is injected into a reactor. In afluidised bed reactor the adsorption agent is kept insuspension by the circulation of the flue gas. Dryprocesses are used for the separation of small loads ofHCl and SO2 as well as for the downstream precipitationof mercury and PCDD/F.

Chemical flue gas treatmentChemical flue gas treatment


Activated carbon is used for the adsorption of

mercury and dioxins / furans. Contaminants are

accumulated on the surface of the activatedcarbon, due to its high specific surface.

Static bed filters (activated carbon)Static bed filters (activated carbon)


18/36

18


Waste incineration plant Spittelau (Vienna,

Austria)

1- waste bunker

3- grate

4- incineration chamber

5- waste heat boiler

6- pre-heating of air

8- electrostatic filter

9- wet scrubber (2-stage)

10- precipitator for particulate matter

11- SCR selective catalytic reduction

17- turbine and generator

19- magnetic separator

20- bottom ash bunker

21- container for metal scrap

22- filter ash silo

25- reactor for sewage purification

26- clean water

27- sludge

28- chamber filter press

29- box for filter cake

Fresh water

alkali process water

acidic process water

saturated vapour

bottom ash

filter ash/bottom ash

hydroxide sludge

gypsum sludge

incineration air

heat

limemilk

causticsoda

Freshwater

naturalgas

ammonia

lime milkprecipitation chemicals




Thermal Treatment of Waste

Residues


19/36

19


Bottom ash:Bottom ash: consists of minerals such as silicate,aluminium oxide, ferrous oxide and carbonate as well asheavy metals (lead, copper, manganese, nickel,chromium, zinc). Bottom ash is landfilled (Austria) or tosome extent conditioned and used for road construction(e.g. the Netherlands).

Filter ashFilter ash: usually has a higher content of organic andinorganic pollutants, therefore its save disposal isrequired. For this reason, filter ash is conditioned infurther processes (e.g. solidification, vitrification).

Wet sorption residueWet sorption residue: waste water from wet scrubbersmust be subjected to special treatment. From thecoagulation and dewatering a filter cake is producedwhich also has to be safely deposited (e.g. undergroundlandfills).

Residues from waste incineration


Bottom

ash

Figure 1: grain of sintered bottom ash

with rust

Figure 2: porous bottom ash with

remainders from plastic and rust

Figure 3: sintered bottom ash with

remainders from plastics and ettringite

(white)

Figure 4: molten piece of metal including

pieces of glass from a bottle


20/36

20


Residue Management in Vienna (2005)

3

Fluidised

bed 1

2

4

Splitting Rinterzelt

Ash from sewage

sluge 21,000 t/a

> 50 mm

Heilbronn

Heilbronn

< 50 mm

landfillAl,

Cu

Fe

solidification with 10%

cement and 5%H2O

Boundary bank for

landfill Rautenweg

Rotary

kiln 1/2

Bed

ash

Incine-

rator 1

Incine-

rator 2

Filterash



Energy recovery


21/36


22/36


23/36


24/36


25/36


26/36


27/36

27


13. Substances and preparations which release toxic or

very toxic gases in contact with water, air or an acid.

14. Substances and preparations capable by any means,

after disposal, ofyielding another substance, e.g. aleachate, which possesses any of the characteristics

listed above.

15. Ecotoxic: substances and preparations whichpresent or may present immediate or delayed risks for

one or more sectors of the environment.

Hazardous characteristics (5)

91/689/EWG; Annex III


Hazardous constituents: examples (1)

Elements and their compounds, e.g.

arsenic, cadmium, mercury, lead, selenium,

beryllium, antimony, tellurium, thallium

Vanadium compounds, nickel compounds, tin

compounds, cobalt compounds

the following alkaline or alkaline earth metals in

uncombined form

lithium, sodium, potassium, calcium, magnesium

acidic solutions or acids in solid form

asbestos (dust and fibres)

91/689/EWG; Annex II


28/36

28


Hazardous constituents: examples (2)

aromatic compounds; polycyclic and

heterocyclic organic compounds

inorganic cyanides

chlorates

halogenated solvents

sulphur organic compounds

PCBs (polychlorinated biphenyl) and/or PCTs

(polychlorinated terphenyl)

91/689/EWG; Annex II


Examples for hazardous wastes (1)

anatomical substances; hospital and other clinical

wastes

pharmaceuticals, medicines and veterinary compounds

wood preservatives

biocides and phyto-pharmaceutical substances

residue from substances employed as solvents

halogenated organic substances not employed as

solvents excluding inert polymerized materials

tempering salts containing cyanides

mineral oils and oily substances (e.g. cutting sludges,

etc.)

91/689/EWG; Annex I.A


29/36

29



oil/water, hydrocarbon/water mixtures, emulsions

tarry materials arising from refining, distillation and any

pyrolytic treatment (e.g. still bottoms, etc.)

inks, dyes, pigments, paints, lacquers, varnishes

resins, latex, plasticizers, glues/adhesives

chemical substances arising from research and

development or teaching activities which are not identified

and/or are new and whose effects on man and/or theenvironment are not known (e.g. laboratory residues, etc.)

pyrotechnics and other explosive materials

photographic chemicals and processing materials

91/689/EWG; Annex I.A



animal or vegetable soaps, fats, waxes

batteries and other electrical cells

ashes and/or cinders

residue from pollution control operations (e.g.baghouse dusts, etc.

scrubber sludges

contaminated containers (e.g. packaging, gascylinders, etc.) whose contents includedhazardous constituents

91/689/EWG; Annex I.B


30/36


31/36


32/36

32


Facilities for the management of

hazardous waste

On-site: facilities for the treatment/ recycling of

hazardous waste are constructed and operated

by the waste generator (i.e. at their production

plant)

Off-site: wastes are transported off site to

specialised facilities for treatment and disposal

(commercial facilities)

LaGrega et al. 1994, p. 405f


Strategies

Waste generation

Recovery/ Recycling: oil recovery

solvent, metal recovery

energy recovery fuel blending Treatment: thermal destruction

physico-chemical

stabilization

biological treatment

Disposal: landfill

underground landfill

Products

Residuals

Residuals

LaGrega et al, 1994, p. 406Prevention


33/36

33


Disposal

Disposal (landfilling) is necessary

for the residual amount of waste which cannot be

prevented or treated

residue from waste treatment

Options for wastes with a high contents of

hazardous contaminants

immobilisation by means of pre-treatment barriers which impede the diffusion of a contaminant

Tabasaran, 1997, p. 199


Underground landfill

using cavities from mining for the disposal of

waste

particularly in evaporite (salt cavities)

Advantages: huge natural barrier

very distant from those zones, in which the transport of

contaminants affects humans

the surface area can be re-cultivated and used

can also be used as packing to improve the stability of

the cavities



34/36

34


Types of underground landfills

3. Landfill body below groundwater table salt cavities situated in a layer which is impermeable

for waterTabasaran, 1997, p. 202f

1. Landfill body above groundwater table if the top side and the sides of the landfill body are

sealed by layers which are impermeable for water

if the groundwater level does not rise in the long

run

2. Landfill body in aquiferous layer no effective separation can be achieved long-term

can only be used for wastes, if an elution does not

cause relevant changes in the composition of the

groundwater (i.e. for water-insoluble waste)


Underground disposal of waste in cavities

from mining


overlying rock

evaporite

waste is permanently

excluded

during operating phase:

accessible, waste can be

retrieved

separate storage of waste

as well as storage in

containers is possible

particular sections can be

sealed

pits in the aquiferous

overlying rock can be

sealed


35/36

35


Deep well injection


waste is permanently excluded

wastes cannot be retrieved

borehole can be sealed in the

aquiferous layer

waste can only be disposed in

cavities which have been

pumped dry before

only free-flowing and pumpable

waste can be disposed by means

of in-situ solidification separate disposal of wastes

within one cavity is not possible

overlying rock

evaporite


Example: Underground disposal in cavities

(Sondershausen, Germany)

ABF-BOKU


36/36


References

BMLFUW: Bundesabfallwirtschaftsplan 2006.

http://www.bundesabfallwirtschaftsplan.at/

EIPPCB: Reference Document on Best Available Techniques for the Waste

Treatments Industries. 08/2005. http://eippcb.jrc.es/pages/Fmembers.htm

EIPPCB: Reference Document on Best Available Techniques for Waste

Incineration. 07/2005. http://eippcb.jrc.es/pages/Fmembers.htm

LaGrega M.D., Buckingham P.L., Evans J.C.: Hazardous Waste Management.

McFraw-Hill, Singapore, 1994

Santoleri J.J., Reynolds J., Theodore L.: Introduction to Hazardous Waste

Incineration. Second Edition. John Wiley & Sons, New York, 2000

Tabasaran Oktay (Hrsg.): Abfallwirtschaft Abfalltechnik, Sonderabflle. VerlagErnst & Sohn, Berlin, 1997


Thank you for your attention!

10 incineration hazardous

Documents