Note: Descriptions are shown in the official language in which they were submitted.
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PROCESS FOR ~AINTAINING A HIGH TEMPERATURE REACTOR
WITH CONTINUOUS CHARGING
The invention relates to a process for maintaining a
high temperature reactor in which the carbon obtained
by the thermsl transformation of organic refuse consti-
tuants or other continuously supplied disposal products
is gasified by msans of o~ygen and the inorganic con-
stituents of said disposal proclucts are melted.
High temperature reactor maintenance processes are
labour-intensive and ex-tremely time-consuming corre-
sponding to the maintenance and repair processes for
blast furnaces, rotary hi].ns, etc. The high opera-tin~
temperatures in such reactors make it necessary to haYe
a thich-walled lining Oe the furnace with appropriate
refractory material, which can be formed from a ramming
material, but in the case of multiple linings is
usually partly formed from prefabricaied refractory
bricks. Cast or rammed linings, as well as refractory
brick furnace linings must be temp~red for a long
period prior to putting into use. On ~topping a
reactor requiring repair it is necessary to wait for a
long time to enable the furnace to cool to a suitable
temperature, For e.~ample, rotary kilns used for refuse
incineration purposes have to be stopped or shut down
twice yearly for in eac~ case 6 weeks, so that the
necessary repairs can be made to the damaged lining.
The situation is similar in the case of. blast furnaces,
in which molten metal is produced or metallurgical
processes take place. In order to reduce the down-
repair times for metal smelting furnaces made necessary
due to the long cooling and reheating periods, in a
process for melting metal scrap and in particular scrap
iron or similar high-melting charges in a cokeless-
operat~d shaft furnace, it is ~lready hnown to lo~er by
moans of a hydraulic device the detachably fitted
furnace underhearth following corresponding wear and
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repair it separately from the furnace shaft ~DE 37 42
3~9 Cl~. Such shaft furnaces are charged discontin-
uously, i.e. the material is charged by means of a gas-
tight closure into the top area of the furnace shaft.
Reference is also made in this connection to a metal
smelting furnace with a vertical furnace shaft and
flanged underhearth, in which the rin~ flange plane is
radially drawn in, so that there is a particularly
easily handlable flanged connection (US patent 4 291
634)-
In the present case it is a question of maintaining thelower part of a high temperature reactor, in which the
carbon obtained~through the thermal trsnsformation o~
organic refuse constituents is gasified by the metered
addition of pure oxygen and the inorganic constituents
are melted and tapped in molten form. The disposal
products are preferably supplied continuously and not
discontinuously by means of a pretreatment zone, such
as a degassing duct, to the reactor underhearth which
is subject to elevated thermal, as well as mechanical
and chemical stresses and loads.
The disposal products of interest here are continuously
subjected to this thermal pretreatment in unsorted,
untreated and in part as liquid components and for this
purpose are forced through the duct receiving same in
the compressed state and in a t~pe of "caking process"
both the liquid and the volatile consti.tuents are
evaporated, The thus pretreated domestic, special or
industrial refuse and waste undergoes the high tempera-
ture treatment in the high temperature reactor in lumpy
state. This avoids the disadvantages of the hitherto
known refuse incineration processes or corresponding
pyrolysis processes, such as are adequately described
in the literature.
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The ~dvantages are in particular closed and therefora
non-environmentally prejudicial procsss engineering,
whilst avoiding the high air flow rat~s necessarily
existing in the case of conventional incineration
plants. In the known melting procasses for previousl~
pyrolyzed disposal products within a high temperature
reactor, in which introduction takes place in the form
of a packed bed, it has been ~ound that it is not
possible to ensure an ad~quate gas permeability within
the packed bed, so that despite high energy costs there
is an inadequate production of gas and vary long
residsnce times in the reactor occur.
The lump-form, continuous introduction of the mat~rial
to be melted into the high temperature reactor reliably
obviates this problem. The hi~h temperature reactor on
which the maintenance procsss according to the invan-
tion is used has a two-part construction, namely an
upper part and a lower part detachable therefrom, i.e.
an upper stabilizing zone for the gas fractions
obtained and the actual ~urnace hearth to which is con-
tinuously supplied the lumpy prstreated molten
material The upper snd lower parts are firmly inter-
connected by means of gas and pressure-tight flange
connections. The high temperaturs reactor is lined
with refractory material in per se known manner, the
lining being such that it is possible for there to be
temperatures within the reactor batween 1600 and
2000C. Into the furnace area below the loose b~d
formed issue preferably several oxygen lanc~s passed
through the hearth lining and which are integrated into
the combined burner and which are received by cooling
j~ckets, which are in turn firmly connected to the
he~rth lining. As a result of the cooling jackets for
the oxygen lances passed radially fro~ the outside to
the inside through the refractory ~aterial, in the
contact area on the inner surface of ths lining a
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temperature gradieQt is formed, which brin~s about an
at least partial retrograde condensation of the
material evapor~ted or liquefied by the oxygen burner,
so that the most variad, uncontrolled chemical
reactions and fusion processes occur. After only
operating the high temperature reactor for a short time
the cooling jackets of the comb:ined burner with the
oxygen supplies are so intenselY fused with the
refractory lining surrounding them that it is no longer
possible to e~tract the same without destroyin~ the
lining. As the cooling jackets only have one coolant
supply line and one coolant drain line, no problems
occur in connection with thair coupling and uncoupling
to the reactor for repair purposes, whilst the oxygen
lances, i.e. the actual combined burner, which are
displaceable within the cooling jackets, are connected
to 8 plurality of control connections, monitoring
members, at least one auxiliary gas line, etc., so -that
their replace~ent would be relatively complicated.
By means of the supply of pure oxygen or oxYgen-
enriched air to the gasification or meltin~ area of the
high temperature reactor, in the vicinity of the com-
bined b~rner plane the lumpy bed, to the extent that it
is constituted by carbon fraotions, is gasified by oxi-
dation, whilst the mineral and metallic constituents
are meltad, in order to directly thereafter flow in
molten form into the homogenizing reactor, which is
preferabl~ lined with a lining corresponding to the
gasification area. The homogenizing reactor construc-
tionally forms a unit with the lower part of the high
temperature reactor. Within the homogenizing reactor
there is a cl~rification of the melt, so that there is
a completely homogeneous molten bath of mineral and/or
metallic components. As a result of the particularly
aggressive chel~ical and mechanical actions, as well as
the high temperature ~alues prevailin~ in the
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gasification area of the high temperature reactor and
the homoganizing reactor, the linings of the walls in
the said areas with refractory material leads -to
particularly hi~h levels of wear, so that the period
durin~ which the high temperature reactor can be used
is limited by the necessary rep~irs or at least
maintenance work.
The high reactor idle times necessarily caused in
accordance with the prior Rrt for repairing the linings
of blast furnaces and high temperature reactors may be
acceptable in the case of intermittently charged cupola
furnaces or the like, but this is not the case where
the supply of the material to be melted or evaporated
takes place continuously as a result of the pretreat-
ment thereof. In refuse treatment plants the refuse is
supplied continuously. The storage of refuse compon-
ents decomposing by rotting or the like, e.~. during
the hot summer period in the plant supply area while
the necessary si~-wae~ repair work is being carried out
is impossible. The logistics on whlch such problem
plants are based must e~clude such idle times. It is
necessary to have alternative disposal means, which can
be used durin~ the many-week repair periods.
The problem of the invention is to provide a mainten-
ance process for high temperature reactors, which are
in particular subject to the aforementioned problems.
which restores to the necessary operating state the
strcngly loaded parts after wear has occurred much more
rapidly than has hitherto been possible, so that the
plant idle iimes can be considerably reduced. The long
maintenance and replir costs must be independent of the
given idle times for the plant.
This problem is sol~ed by the features of the claim.
It is essential to the invention that for such a high
temperature reactor with a continuous reactor material
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supply, there is a subdivision into a fixed reactor
part and a part which is detachablc and removable
therefrom, so that the replacement of this displaceable
reactor part is possible in a short time and is in-
dependent of the actual maintanance or repair work,
The charging of such a reactor only has to be
interrupted during the replacemlent of th~ dctachable
reactor part and the detachment and removal of this or
similar parts and their replacement by new or repaired,
identical parts requires a period of time which is
independent of the actual maint~3nance and/or repair.
As soon as reactor charging is interrupted for the
planned replacement ~nd the solids still present in the
lower hearth part are melted or gasified and the
remaining molten bath has been discharged, it is
possible to start the detachment of the flanges between
the upper and lower parts of the high temperature
reactor, whilst simultaneously or possibly shortly
before or afterwards the oxygen lances can be ~ithdrawn
from their cooling jackets. without it being necessary
to interrupt the various connections thereof to
control, checking, supply and removal units. The high
temperature reactor underhearth. which forms a con-
structional unit with the molten bath container, is
only lo~ered by a few ~illimetres compared with the
fi~ed-installed upper part of the reactor and is drawn
out of its operating position. Time-synchronized with
this process a corresponding reserve unit can be moved
up to the high temperature reactor and the emplacement
thereof for ~langing to the upper part of the high
temperature reactor can take place. A sufficient time
beforehand it is necessary to haat the reserve unit to
a high temperature close to the operating temperature,
e.g. 800C. This makes it possible, directly following
the production of the pressure-tight connection between
the lower and upper parts, to resume th re~ctor
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charging briefly interruPted for the replacsment repair
operation During the flangin~ procass simultaneously
the oxygen supplies are introduced into the cooling
jackets of the reserve unit, so that their operation
can be resumed immediately thereafter.
The lower reactor part to be repaired and which is
still at the hot operating temperature can now be
cooled independently of the return to op~ration of the
plant and on reaching a temperature acceptable for the
repairs it can again be restored to a perfect operating
condition. Only when a further repair proves necessary
is the intact reserve unit heated, so that it is ready
to operate at the time of the ne~t rapid rcplacement.
The idle and repair times lasting several weeks
necessary for high temperature reactors or comparable
combustion or melting furnaces are reduced to a few
hours as a result of the replacement procsss according
to the invention, which guarantees the quasi-continuous
operation of the complete plant, increases product-
ivity, improves the operating safety and e~cludes
ha~ards to the environment and risks to the operating
personnel.
