U.S. patent application number 12/833088 was filed with the patent office on 2011-02-10 for incineration plant with heat insulating layer on the wet slag.
This patent application is currently assigned to KARLSRUHER INSTITUT FUER TECHNOLOGIE. Invention is credited to Thomas Kolb, Michael Nolte, Helmut Seifert, Wolf-Dieter Zeidler, Bernd Zimmerlin.
Application Number | 20110030591 12/833088 |
Document ID | / |
Family ID | 42935671 |
Filed Date | 2011-02-10 |
United States Patent
Application |
20110030591 |
Kind Code |
A1 |
Kolb; Thomas ; et
al. |
February 10, 2011 |
Incineration plant with heat insulating layer on the wet slag
Abstract
An incinerator including a wet slag remover for discharging
combustion residues that includes a tank configured to provide a
water bath having a water surface adapted to receive the combustion
residues. A heat insulation layer is configured to float on the
water surface. The heat insulation layer includes a plurality
floating bodies that are movable relative to one another.
Inventors: |
Kolb; Thomas; (Edenkoben,
DE) ; Nolte; Michael; (Goslar, DE) ; Seifert;
Helmut; (Ludwigshafen, DE) ; Zeidler;
Wolf-Dieter; (Ettlingen, DE) ; Zimmerlin; Bernd;
(Rheinstetten, DE) |
Correspondence
Address: |
Leydig, Voit & Mayer, Ltd. (Frankfurt office)
Two Prudential Plaza, Suite 4900, 180 North Stetson Avenue
Chicago
IL
60601-6731
US
|
Assignee: |
KARLSRUHER INSTITUT FUER
TECHNOLOGIE
Karlsruhe
DE
|
Family ID: |
42935671 |
Appl. No.: |
12/833088 |
Filed: |
July 9, 2010 |
Current U.S.
Class: |
110/235 ;
110/346 |
Current CPC
Class: |
F23J 2900/01006
20130101; F23J 1/00 20130101; F23J 1/08 20130101; F23J 2900/01002
20130101 |
Class at
Publication: |
110/235 ;
110/346 |
International
Class: |
F23G 5/02 20060101
F23G005/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2009 |
DE |
10 2009 032 760.6 |
Claims
1-16. (canceled)
17. An incinerator comprising a wet slag remover for discharging
combustion residues, the wet slag remover comprising: a tank
configured to provide a water bath with a water surface adapted to
receive the combustion residues; and a heat insulation layer
configured to float on the water surface, the heat insulation layer
including a plurality floating bodies that are movable relative to
one another.
18. The incinerator recited in claim 17 wherein each of the
floating bodies are rotatable about at least one axis of
rotation.
19. The incinerator recited in claim 17 wherein the floating bodies
include a thermal emissivity E between 0 and 0.96.
20. The incinerator recited in claim 17 wherein the floating bodies
include refractory materials.
21. The incinerator recited in claim 17 wherein the floating bodies
are hollow bodies.
22. The incinerator recited in claim 17, wherein the floating
bodies include porous material.
23. The incinerator recited in claim 17, wherein the floating
bodies include metal.
24. The incinerator recited in claim 23, wherein the floating
bodies include high-grade steel.
25. The incinerator recited in claim 17, wherein the floating
bodies include ceramic.
26. The incinerator recited in claim 17, wherein the floating
bodies include temperature resistant plastics material.
27. The incinerator recited in claim 17, wherein the floating
bodies include glass.
28. The incinerator recited in claim 17, wherein the floating
bodies have an outside surface and include a reflective coating
disposed on the outside surface.
29. The incinerator recited in claim 17, wherein the floating
bodies are spherical.
30. A method of discharging combustion materials from an
incinerator into a wet slag remover, the method comprising:
providing an incinerator including a wet slag remover including a
tank providing a water bath having a water surface adapted to
receive combustion residues; providing a plurality of floating
bodies on the water surface so as to form a heat insulation layer
on the water surface, the floating bodies being movable relative to
one another; burning solids so as to form the combustion residues;
discharging the combustion residues into the wet slag remover such
that the combustion residues penetrate the heat insulation layer
before entering the water bath.
31. The method recited in claim 30, wherein each of the floating
bodies are rotatable about at least one axis of rotation.
32. The method recited in claim 30, wherein the floating bodies are
moved as the combustion residue penetrates the heat insulation
layer.
33. The method recited in claim 32, wherein after penetration of
the combustion residue, the floating bodies move so as to reform
the heat insulation layer on the water surface.
Description
[0001] The present invention relates to an incinerator which
comprises a wet slag remover having a flexible heat insulation
layer. The invention further relates to a method for
resource-saving operation of an incinerator having a wet slag
remover, in particular as regards the heat discharge from the
combustion chamber into the deslagging bath.
[0002] In general, many incinerators, such as cylindrical rotary
furnaces or grate furnaces, consist of a two-stage combustion. In a
first stage, predominantly solids are burnt, whilst afterburning in
the gaseous phase generally takes place in a second stage. The
substances used in this context are not only disposed of in an
environmentally friendly manner, where residues or waste materials
are involved, but are also predominantly used for energy
production, i.e. the hot flue gases resulting from the combustion
are used in a heat recovery boiler to produce process steam, which
can subsequently be fed into the district heating network or
converted into electrical energy (current).
[0003] To operate an incinerator of this type as efficiently as
possible and thus achieve high energy efficiency, heat losses,
above all surface losses due to heat conduction, convection, and
radiation, must be kept low before entry into the heat recovery
boiler. In the furnace of an incinerator, heat loss is reduced by
various insulating layers in the refractory lining. The lower the
heat loss in the firing region, the greater the subsequent energy
yield in the form of process steam. The amount of process steam is
a substantial source of revenue for incinerator operators.
[0004] However, the wet slag remover, which is conventionally
located between the first and second combustion stages of an
incinerator of this type, is a source of heat loss which has been
given little consideration until now. The inert, burnt-out residues
from the solid combustion (first combustion stage) are discharged
via the wet slag remover in a dry (ash) or molten (slag) form.
[0005] In cylindrical rotary furnaces, for example, this discharge
is generally in a molten form. The molten slag thus falls or drops
from the cylindrical rotary kiln into a water bath via a drop
chute, the slag being quenched abruptly upon entering the water
bath. The cooled, hardened slag is removed from the water bath of
the wet slag remover into a collecting vessel via a conveyor system
as a solid, vitreous residue and is subsequently supplied to
further treatment processes.
[0006] The wet slag remover not only offers the possibility of
transferring inert solids out of the furnace, but at the same time
also forms the air seal preventing secondary air from entering the
furnace from outside. This air seal makes it possible to operate
the incinerator at a reduced pressure.
[0007] Complex physical and chemical processes take place during
combustion. Because of the high temperature and energy state
thereof, the intermediate and end products of the combustion (such
as CO.sub.2, CO, hydrocarbons, H.sub.2O, soot, ash, etc.) emit
electromagnetic waves in the form of light. The spectrum of the
electromagnetic waves ranges from the short-wave UV to the
long-wave IR range. If these electromagnetic waves impinge on the
surface of bodies (such as particles, furnace walls, wet slag
remover water), absorption and reflection processes take place on
the surface. If the radiation is absorbed by the body, the
temperature thereof increases in accordance with Kirchhoff's law of
thermal radiation, and this in turn leads to an increased emission
of thermal/heat radiation.
[0008] The emissivity .epsilon. of a body describes the ratio of
the radiation absorbed by the body to the radiation incident
thereon. The lower the emissivity .epsilon., the lower the
absorption and the greater the reflection of the incident
radiation. If the emissivity .epsilon.=1, this is an ideal black
body which completely absorbs any radiation incident thereon. The
radiation absorbed by the body is converted into heat and
subsequently emitted back into the environment evenly in all
directions in the form of heat/thermal radiation.
[0009] Hot furnace walls (.epsilon.=approx. 0.8) absorb the
majority of this radiation, but also reflect a not inconsiderable
proportion back into the interior of the furnace. However, if
electromagnetic radiation reaches the dark water surface of a wet
slag remover (.epsilon.=approx. 0.96-0.98), almost all of the
incident radiation is absorbed. The water temperature of the wet
slag remover begins to rise and evaporation is promoted at the
surface of the water. The low radiation reflection at the water
surface and the relatively cold water vapour which escapes from the
wet slag remover and mixes into the hot combustion gas in the
system lead to an undesired reduction in the flue gas temperature,
in particular at the transition from the cylindrical rotary kiln
into the afterburning chamber. A further disadvantage in this
connection is the increased consumption of process water.
[0010] In particular in cylindrical rotary systems having small
diameter-length ratios, in which there are already relatively high
heat losses due to large surface areas (in relation to volume), or
in operating modes having large load fluctuations, a temperature
reduction of this type at the transition from the cylindrical
rotary kiln to the afterburning chamber can lead to rapid and
undesired cooling of the molten slag near the kiln discharge. The
molten slag will already start to solidify at the kiln discharge.
If cooling of the slag at the kiln discharge results in what are
known as slag runs, which slowly grow out of the cylindrical rotary
kiln, this can make continuous slag discharge difficult. If these
slag runs become too large, they break off under the weight thereof
and fall into the wet slag remover in hot lumps. If relatively
large lumps of slag break off in an uncontrolled manner, the wet
slag remover and other system components may be damaged as a result
of heavy impacts. In extreme cases this damage may even make
immediate shutdown of the whole incinerator necessary and thus lead
to high repair costs.
[0011] If the slag solidifies too rapidly at the kiln discharge
because of an excessively high temperature gradient, there will
already be solidification in the inside of the kiln. Build-up of
slag near the kiln discharge leads to gradual accretion on the
cylindrical rotary kiln. The low diameter at the kiln discharge
shrinks until controlled system operation is no longer possible. In
this case too, the entire system must be shut down at once and the
slag must subsequently be broken down mechanically. However, the
system operator may use various methods to address the problem of
the slag discharge from the cylindrical rotary kiln.
[0012] One possibility for facilitating slag discharge is to use
what are known as slag strippers. These permanently installed slag
strippers prevent the formation of larger slag runs, since the slag
growing out of the combustion chamber is stripped off at the slag
strippers and falls downwards into the wet slag remover. Thus,
using slag strippers can prevent excess loading of the wet slag
remover and of the entire incinerator. There is considerable
mechanical and thermal stress on these strippers. Instead of slag
strippers, additional tipping torches may also be installed near
the slag discharge. Permanent or even just brief use of torches of
this type may raise the temperature (in particular the slag
temperature) considerably at the transition from the cylindrical
rotary kiln to the afterburning chamber. Slag discharge is
facilitated, since higher temperatures lead to a substantially more
fluid slag having a lower viscosity, which cools more slowly and
can therefore be removed more easily from the cylindrical rotary
kiln. Tipping torches can prevent the formation of relatively large
slag runs or even accretion of slag on the cylindrical rotary kiln.
Disadvantages of this are the expense of construction and the
increased fuel consumption, which increases the operating
costs.
[0013] The main problem region for the loss of radiant heat is the
direct contact between the water surface of the wet slag remover
and the combustion chamber. No solutions for reducing the heat
losses at the wet slag remover are known from the prior art.
[0014] On this basis, the object of the invention is to provide an
incinerator having a wet slag remover and a method for discharging
combustion residues which mitigate the disadvantages of the state
of the art.
[0015] In particular, this is intended to reduce the heat losses at
the wet slag remover of an incinerator, so as to increase the
system efficiency. Moreover, the slag discharge is to be improved
when using cylindrical rotary kilns by thermal optimisation at the
wet slag remover. A further aim of the invention is to reduce the
evaporation of water at the wet slag remover. At the same time,
however, the entry of combustion residues from the combustion
chamber into the water bath of the wet slag remover, in the form of
solid or liquid slag or ash, should not be impaired.
[0016] It is further an object of the invention to propose a method
with which an incinerator having a wet slag remover can be operated
in a resource-saving manner by comparison with the prior art.
[0017] The object is achieved by an incinerator having a wet slag
remover in accordance with the features of claim 1 and a method for
discharging combustion residues according to claim 14. Advantageous
configurations are specified in the subclaims.
[0018] A solution for inhibiting the loss of radiant heat from the
combustion chamber of an incinerator is to cover the water surface
of the wet slag remover with a flexible heat insulation layer. This
heat insulation layer comprises a plurality of floating bodies
which separate the water surface from the combustion chamber, in
such a way that the radiant heat predominantly impinges on the
floating bodies and not on the water surface.
[0019] The floating bodies are movable relative to one another. In
this context, movable means that the floating bodies can move
horizontally on the water surface, forming a gap, so as to let
falling combustion residues pass. Furthermore, the floating bodies
can move vertically, and this in particular makes displacement of
individual floating bodies possible between a plurality of
layers.
[0020] In a preferred embodiment, the floating bodies have at least
one rotational degree of freedom. Rotational degrees of freedom are
movements about one of the three axes of rotation of the floating
body in which the centre of gravity of the body is not displaced.
If combustion residues fall from the combustion chamber onto the
floating bodies having a rotational degree of freedom, there is a
momentary deflection of the centre of gravity, to which the
floating bodies react with a rotational movement which moves the
combustion residues onwards towards the water bath. The rotational
movements in this context are not restricted to complete rotation,
but also include tilting movements, in which the body rotates back
into the starting position after the rotational movement.
Consequently, in a particularly preferred embodiment, at least one
axis of rotation of the floating bodies is not parallel to the axis
of the gravitational field. The axis of rotation is preferably at
an angle of between 0.degree. and 89.degree., more preferably
between 0.degree. and 45.degree., to the water surface
[0021] These features cause the floating bodies to function as a
flexible barrier in such a way that the combustion residues from
the combustion chamber can pass through the heat insulation layer
consisting of floating bodies into the water bath. The floating
bodies automatically organise themselves into a generally closed
layer because of the buoyancy thereof, the weight thereof and the
water movement when slag portions penetrate.
[0022] In a preferred embodiment, the floating bodies are
manufactured from a material having an emissivity .epsilon. which
is less than that of the water, i.e. between 0 and 0.96,
particularly preferably between 0.01 and 0.2 (values for polished
metal surfaces or metallised surfaces). This makes it possible to
provide that a considerable proportion of the heat radiation is
reflected back into the combustion chamber.
[0023] In a further preferred embodiment, the floating bodies are
manufactured from materials which in the ideal case make
maintenance-free long-term operation possible. Accordingly,
temperature-resistant, preferably refractory materials are
required, since high temperatures prevail in the combustion
chamber. Depending on the system design, the fuel and the height of
the drop chute, temperatures of approximately 150.degree.
C.-200.degree. C. are to be expected above the water surface of a
conventional wet slag remover without a cover. In addition, the
falling slag is even hotter when it strikes the floating bodies.
Accordingly, temperature-resistant or refractory materials
exhibiting heat resistance at temperatures of at least 200.degree.
C. are required for the surface of the floating bodies.
[0024] A further aspect is the mechanical stress resistance of the
floating bodies, since the falling combustion residues might damage
the floating bodies. Preferred materials in this context are metal
materials, in particular high-grade steels, since these also have a
high resistance to corrosion, as well as mechanical dimensional
stability. Further, metal surfaces have a low emissivity; for
example, polished iron has an emissivity .epsilon. of between 0.04
and 0.19. Steel alloys comprising chromium, nickel, molybdenum,
titanium or vanadium may preferably be used.
[0025] Ceramic materials are a further preferred material for the
floating bodies. Ceramic materials are also distinguished by high
dimensional stability and mechanical stress resistance. Advanced
ceramic materials or engineering ceramic materials are used in
particular. In this context what are known as non-oxide ceramic
materials (for example nitrides, carbides or borides) may be used,
and these are distinguished by a largely grey to dark grey
colouring; preferably, however, oxide ceramic materials (for
example aluminium oxide, titanium dioxide, zirconium dioxide),
which are white to yellow in colour and therefore have a preferred
lower emissivity, may be used.
[0026] Temperature-resistant plastics materials may be used as
further preferred materials for the floating bodies.
Polyfluorinated plastics materials such as polytetrafluoroethene
(Teflon.RTM.) or polyfluorinated rubber (Viton.RTM.) are
particularly preferably used for this purpose. In this context,
temperature-resistance means heat-resistance at temperatures of at
least 200.degree. C. According to the manufacturers the
heat-resistance of Viton.RTM. is 200.degree. C. and that of
Teflon.RTM. is 260.degree. C.
[0027] Because of the high specific densities thereof, metals,
ceramic materials and plastics materials generally do not float and
should preferably be manufactured as hollow bodies. Alternatively,
the floating bodies may be manufactured from porous material, the
pores preferably being closed.
[0028] Floating bodies of which the surface comprises a reflective
coating, which affords the bodies a particularly low emissivity,
are preferred. A coating can also seal an open porosity.
Advantageously, the surface is additionally smoothed or
polished.
[0029] In a further preferred embodiment, the floating bodies are
spherical.
[0030] In a particular aspect, the invention relates to the use of
a heat insulation layer for wet slag removers in incinerators,
comprising a plurality of floating bodies which are movable
relative to one another and preferably rotatable about at least one
axis of rotation.
[0031] Because of the flexible construction thereof with a
plurality of floating bodies, the heat insulation layer according
to the invention can be used in various incinerators having wet
slag removers. Existing incinerators can also be retrofitted simply
without additional constructional measures on the wet slag
remover.
[0032] When the heat insulation layer according to the invention is
used in incinerators, the operating temperature in the combustion
chamber rises and the heat loss at the wet slag remover is reduced.
As a result, an additional energy input to compensate for heat
losses and/or to liquefy slag components is unnecessary. In
particular in incinerators having a cylindrical rotary furnace, the
discharge of slag from the incinerator is simplified since the slag
does not solidify.
[0033] Optionally, a plurality of layers of floating bodies may be
used, in such a way that the water surface is maximally covered.
For this purpose, floating bodies of different sizes may optionally
be used.
[0034] A further advantage of the construction according to the
invention of the incinerator is the greatly reduced evaporation of
the water in the wet slag remover. In normal operation of a
conventional incinerator without a heat insulation layer, the water
bath is heated to approximately 30.degree. C. to 80.degree. C., and
this represents a considerable heat loss. Moreover, substantial
evaporation takes place at this temperature. The radiant heat
incident on the water surface accelerates the evaporation process.
The evaporation of water is an endothermic process; the necessary
evaporation enthalpy is lost from the system and is a further
source of energy loss in incinerators. The floating bodies of the
insulating layer reduce the contact area between the water bath and
the gas chamber (combustion chamber). In this way, the evaporation
of water from the wet slag remover into the combustion chamber is
also reduced. Reduced process water consumption is a further
advantage of the invention.
[0035] According to the invention, the combustion residues from
incinerators having wet slag removers are discharged by the
following method. Initially, an incinerator is provided with a tank
serving as a water bath for receiving combustion residues (wet slag
remover), comprising a floating heat insulation layer which is made
up of a plurality of floating bodies which are movable relative to
one another. Subsequently, the solid combustibles such as
production residues from industry, household waste, substitute
fuels, coal or biomass are burnt up in the combustion chamber. This
may take place in a grate furnace or a cylindrical rotary furnace,
but also in coal combustion boilers. In the following method step,
the resulting combustion residues (slags, ash) are discharged into
the water bath of the wet slag remover at the end of the rotary
cylinder or the grating in the lower part of the coal combustion
boiler via a drop chute, the combustion residues penetrating the
heat insulation layer before entering the water bath.
[0036] Since according to the invention this water bath is covered
by a heat insulation layer made up of floating bodies, the residues
initially fall onto the floating bodies, which because of the
degrees of freedom of movement thereof do not, however, form a
barrier, but instead allow the residues to pass into the water
bath. In this case, the floating bodies may be displaced either
horizontally or vertically to form a gap.
[0037] The floating bodies preferably have at least one axis of
rotation about which they can rotate. The rotational movement comes
about when the combustion residues are discharged in that the
centre of gravity of the floating bodies is altered by the
impacting solids in such a way that a rotational or tilting
movement occurs in the gravitational field as a result and conveys
the combustion residues into the water bath. This applies in
particular to spherical floating bodies.
[0038] After the combustion residues have passed the heat
insulation layer, the floating bodies spontaneously organise
themselves into a closed layer. If individual floating bodies are
damaged or made unusable during relatively long operation of the
heat insulation layer, or if floating bodies are lost when the
combustion residues are transported away from the wet slag remover,
new floating bodies can easily be applied to the water surface of
the wet slag remover.
[0039] In the following, the invention is explained by way of
embodiments and the appended drawings.
[0040] FIG. 1 shows an incinerator having a cylindrical rotary kiln
and a wet slag remover from the prior art.
[0041] FIG. 2 is a schematic drawing of the pilot scale test setup
of a wet slag remover.
[0042] FIG. 3 is a graph showing the progression of the temperature
in the wet slag remover test setup of FIG. 2 as a function of the
height above the water surface.
[0043] FIG. 1 shows by way of example a cross-section of the
construction of a conventional incinerator having a first
combustion stage 1 and a second combustion stage 2. Solid packages
are conveyed via a conveyor chute 3 into the combustion chamber of
the first combustion stage 1, where they are burnt up. After
combustion, the slags 4 fall through a drop chute 5 into the water
bath 7 of the wet slag remover 6. The hot flue gases escaping from
the first combustion stage 1 pass into the gas chamber 8 of the
second combustion stage 2. In the second combustion stage 2
(afterburning chamber) the gaseous phase of the flue gases, which
are sometimes insufficiently burnt out, is burnt out using
afterburning chamber burners. Consequently, considerable heat
radiation prevails in this gas chamber 8 and radiates out into the
water bath 7 of the wet slag remover 6. The radiation incident on
the water bath 7 is mostly absorbed.
[0044] The pilot scale test setup of a wet slag remover shown in
FIG. 2 was developed to simulate the basic processes in a wet slag
remover 6 of an incinerator. This test setup basically consists of
the individual components of a radiation source 9, a water bath 7
and a gas chamber 8 having external insulation 11. The radiation
source 9 consisted of 4.times.100 W light emitters and the external
insulation 11 consisted of mineral fibre mats/insulating material
(approx. 8 cm thick). An extensive data capture system was
installed in the gas chamber 8 between the radiation source 9 and
the water bath 7, as well as in the water, and comprises a
plurality of thermocouples 10 and a water level indicator 14.
[0045] By way of example, temperature measurements and water level
measurements which realistically reproduce the temperature
distribution in the wet slag remover 6 of an incinerator were
carried out on this test setup. The temperature distribution 17-20
was measured as a function of the height above the water surface 16
of the water bath 7 (see FIG. 3), the water bath 7 being free from
floating bodies 12 on the one hand and covered with hollow glass
bodies by way of floating bodies 12 on the other hand.
[0046] Changes in the temperature distribution in the water bath 7
and in the gas chamber 8 and the evaporation amount were recorded
using a data capture system. By balancing, it was possible to
compare the test results with one another and check the
plausibility thereof.
[0047] FIG. 3 shows the measured temperature progressions 17-20
above the water surface in the gas chamber 8 of the test setup of
FIG. 2 with and without using floating bodies 12. The tests carried
out showed that by comparison with the uncovered water surface, a
considerable increase in the average gas temperature 15 above the
water surface can be achieved merely by using floating bodies 12.
By using hollow glass spheres with a diameter of 50 mm without a
coating (emissivity .epsilon.=approx. 0.94, temperature progression
18), it was already possible to increase the average gas
temperature 15 by approximately 15-20%. At the same time, the
evaporation amount sank by approximately 15%.
[0048] If the effect of the emissivity is now taken into account,
the result achieved can be considerably improved. FIG. 3 shows the
temperature progressions 17-20 in the gas chamber above the water
surface as a function of the emissivity of the floating body
surface (glass hollow spheres having a diameter of 50 mm). For this
purpose, glass hollow bodies which either were untreated
(emissivity .epsilon.=0.94, temperature progression 18) or had the
surfaces thereof treated, for example lacquered matt silver
(emissivity .epsilon.=0.45, temperature progression 19) or
metallised (emissivity .epsilon.=0.03, temperature progression 20),
were used to produce different emissivities while using the same
material. It can be seen that as the emissivity decreases, the
average gas temperature 15 above the water surface increases. The
average gas temperature 15 could be increased by approximately
30-40% for the metallised hollow glass spheres (.epsilon.=approx.
0.03) by comparison with the test setup without a heat insulation
layer 13, while at the same time the evaporation amount decreased
by up to 35%.
[0049] For a large commercial system having furnace temperatures of
850-1200.degree. C., it is to be expected that even substantially
lower temperature increases of approximately 10% (corresponding to
a temperature increase of approximately 100.degree. C.) would be
sufficient to facilitate the slag discharge from the cylindrical
rotary kiln considerably. The tests on the wet slag remover test
setup of FIG. 2 therefore demonstrated a considerable potential to
increase gas temperatures 15 so as to facilitate slag discharge and
increase system efficiency.
LIST OF REFERENCE NUMERALS
[0050] 1 first combustion stage [0051] 2 second combustion stage
[0052] 3 conveyor chute [0053] 4 slag [0054] 5 drop chute [0055] 6
wet slag remover [0056] 7 water bath [0057] 8 gas chamber [0058] 9
radiation source [0059] 10 thermocouples [0060] 11 external
insulation [0061] 12 floating bodies [0062] 13 heat insulation
layer [0063] 14 water level indicator [0064] 15 gas temperature
[.degree. C.] [0065] 16 height above the water surface [mm] [0066]
17 temperature progression in the gas chamber without floating
bodies [0067] 18 temperature progression in the gas chamber having
floating bodies with an emissivity .epsilon.=0.94 [0068] 19
temperature progression in the gas chamber having floating bodies
with an emissivity .epsilon.=0.45 [0069] 20 temperature progression
in the gas chamber having floating bodies with an emissivity
.epsilon.=0.03
* * * * *