Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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An apparatus for thermally treating organic material and
method for using the apparatus
Field of the invention
The invention relates to an apparatus for thermally treating organic material
in
order to separate carbon from organic material as defined in the preamble of
the
independent claim 1.
The invention also relates to a method for using an apparatus according to
claims 1 to 8.
The background of the invention is in the method for producing biocarbon and
the present invention provides an apparatus for the method for producing said
biocarbon. The apparatus is called a carbonizer because the method aims for
the
maximization of charcoal. Although the process can be adapted to maximize
vapors
or heat developing during the process, the apparatus can still be called as
carbonizer.
The carbonizer is based on a pyrolysis reaction where organic material is fed
into the
carbonizer and treated by in dry distillation. During pyrolysis the organic
material
undergoes changes in a process where the material is heated to around 450 -
600 C in
the absence of air and the organic material is in the carbonizer approximately
10 - 20
minutes such that the process yields charcoal, pyrolysis gases and organic
vapors. The
time depends on the raw material that is used and its moisture content. The
operation
of the process is continuous and energy efficient. The gas that develops in
the
pyrolysis process is burned to create energy for the process itself. The
organic vapors
can be condensed to bio-oil. The bio-oil can be further refined into pitch.
Different types of pyrolysis reactors are known in the prior art. One type of
pyrolysis reactor is a reactor that has no solid movement through the reactor
during
the pyrolysis process. Other types of reactors work with solids that move
through the
reactor. Those kind of reactors have solved the movement requirement in
different
ways, one having a moving bed, the other causing the movement by mechanical
forces and the third causing the movement by fluid flow. Pyrolysis reactors
can
supply heat also different ways, for example by burning the raw material
inside the
reactor or by using direct heat transfer from hot gases produced by combustion
of one
or more of the pyrolysis products or any other fuel outside the reactor or by
using
indirect heat transfer through the reactor walls having an external heat
source.
A heated screw fed converter, called Thompson Converter is known in the
prior art. The Thompson Converter consists of at least one metal tube heated
externally where the raw material is conveyed through said at least one heated
metal
tube by means of screws in a longitudinal direction of the process chamber
such that
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the raw material gets carbonized during the process. When the raw material is
carbonized during the movement through the process chamber the carbonized
material
will be removed in the end of the converter and passed to a collecting
conveyor which
moves the carbonized material out of the process chamber. The pyrolysis gases
that
are developed during the process are conveyed inside the screw from the end
part of
the screw toward the starting point where the raw material enters to the
screw. The
volatile gases are fed back into the burner such that the operation becomes
self
sustained. The combustion gas is removed from the process chamber through a
discharge outlet, such as a stack.
JP 2006274201 A discloses a continuous reduced-pressure drying
carbonization apparatus in which a liquid containing waste material is dried
and
carbonized. The apparatus comprises a carbonization chamber and a heating
furnace
where the carbonization chamber is formed of multiple screw kneading machines
which are mutually connected. This means that they are connected in series
such that
the waste material goes through all the kneading machines before it is removed
from
the apparatus. The heating furnace is a combustion heating furnace equipped
with the
combustion apparatus where the combustion apparatus is a kerosene burner. The
heating furnace is equipped with a heating zone formed on the upper part of
the
heating furnace and a heat source zone in the lower part of the heating
furnace in
which a burner tip of the combustion apparatus is arranged at a side wall
protrusion
part of the heat source zone.
Objective of the invention
The object of the invention is to provide an effective apparatus for producing
biocarbon which is in addition self-sustaining. The object of the invention is
also to
provide advantageous methods for using said apparatus.
Short description of the invention
The apparatus of the invention is characterized by the definitions of the
independent claim 1.
Preferred embodiments of the apparatus are defined in the dependent claims 2
to 8.
The method for using the apparatus is characterized by the definitions of the
claims 9 to 11 and preferred embodiment of the method is defined in the
dependent
claim 12.
The invention provides an apparatus for producing biocarbon. The apparatus,
i.e. the carbonizer, separates carbon from the incoming organic material by
treating it
thermally. The carbonizer comprises a combustion chamber for thermal treatment
of
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organic material, said combustion chamber comprising a combustion apparatus
for
heating said combustion chamber, conveyor means for conveying organic material
during thermal treatment of organic material, said conveyor means extending
through
the combustion chamber from the outside of the combustion chamber and to the
outside of the combustion chamber and being closed from the combustion
chamber,
said conveyor means being configured for distributing heat from the combustion
chamber to the organic material such that the organic material is thermally
treated,
said conveyor means being configured for conveying also pyrolysis gas
developed
during said thermal treatment. The carbonizer also comprises feeding means for
receiving organic material and for feeding said organic material to the
conveyor mean,
said feeding means is arranged outside of the combustion chamber and removal
means for removing the thermally treated organic material from the conveyor
means
to a next phase.
The combustion chamber acts as a reactor where the thermal treatment
happens, although inside the conveyor means. The carbonizer also comprises a
gas
burner arrangement for arranging a flame to the combustion chamber. The
organic
material is conveyed in the carbonizer by conveyor means which is arranged in
a
closed access system in a longitudinal direction inside the combustion
chamber. The
gas burner heats the combustion chamber and the organic material undergoes
thermal
treatment during the movement through the combustion chamber inside the
conveyor
means. The conveyor means is preferably a screw conveyor but other type of
conveyor means are also possible, for example a mixing worm which mixes the
material inside the conveyor can be used. During the thermal treatment
pyrolysis gas
is released and it is arranged to move inside the conveyor means preferably to
the
opposite direction than the organic material. Pyrolysis gas is lead inside the
conveyor
means as a return flow toward the feeding means, i.e. toward the incoming end
of the
conveyor means where the organic material is fed to the conveyor means and the
gas
is redirected outside the combustion chamber to a pipeline through which it
flows to a
combustion apparatus such as a gas burner. In other words a pipeline is
arranged
outside of the combustion chamber for conveying pyrolysis gas coming through
the
conveyor means and from the conveyor means through the pipeline to the
combustion
apparatus such that the pyrolysis gas cools down and is burned in the
combustion
apparatus for creating heat inside the combustion chamber. The pyrolysis gas
is
configured to be conveyed continuously during thermal treatment from the
conveyor
means to the combustion apparatus. The pyrolysis gas is burned in the
combustion
apparatus, i.e. in the gas burner continuously during the operation of the
apparatus and
the combustion apparatus is arranged to create a flame inside the combustion
chamber
such that it heats the walls of the combustion chamber and radiates heat to
the
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conveyor means. In other words the flame radiates heat inside the combustion
chamber and toward the conveyor means. The flame of the gas burner heats the
side
walls of the combustion chamber and both the heat from the walls as well as
the
radiation heat coming from the flame heats the conveyor means in which the
organic
material moves and becomes thermally treated. The combustion gas is lead to a
discharge outlet and the thermally treated organic material is removed from
the
conveyor means through removal means in the end of the conveyor means. The
removal means is preferably arranged outside of the combustion chamber. The
pyrolysis gas moving inside the conveyor means heats the incoming organic
material
coming against pyrolysis gas and at the same time pyrolysis gas cools down.
While
pyrolysis gas heats the incoming organic material most of the particles of
pyrolysis
gas are absorbed to the organic material. Pyrolysis gas flows with its own
pressure
through the pipeline from the conveyor means to the combustion apparatus
because it
tries to get to a lower pressure.
When pyrolysis gas is formed in the process space, i.e. in the conveyor means,
it contains tar and when pyrolysis gas flows out of the conveyor means and
toward the
combustion apparatus the tar is preferably separated from the pyrolysis gas.
The
pyrolysis gas is processed by a separation arrangement before it is burned in
the
combustion chamber. The tar separated from pyrolysis gas is used for example
to
produce carbon briquettes from the thermally treated organic material by
grinding it
and mixing therein tar separated from the pyrolysis gas and compressing these
ingredients into briquettes. Pyrolysis gas formed by heat transfer from the
process
space into the organic matter to be processed contained in the conveyor means
is
conveyed into the combustion chamber provided in the process space for
combustion
of the gas, the combustion gas formed in the combustion chamber is discharged
from
the process space by means of a discharge outlet in the upper part of the
combustion
chamber and the thermally treated carbonized matter is discharged from the
conveyor
means for further processing. To separate the tar contained in the pyrolysis
gas
formed in the process space the gas is processed before combustion in the
combustion
chamber by a separation process. As a preferred embodiment of the separation
of tar
the pyrolysis gas is preferably cooled for example by a heat exchanger
arrangement
before being fed to a separation arrangement. In a further embodiment the tar
contained in the pyrolysis gas is separated by an electrostatic precipitator
(ESP). As a
yet further embodiment the pyrolysis gas is cooled to about 30 C before being
fed to
a separation arrangement.
The conveyor means is preferably arranged substantially air tight in respect
of
the environment and it continuously conveys the organic material coming from
the
feeding means to the conveyor means and through the conveyor means. The
organic
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material moving through the conveyor means undergoes thermal treatment such
that
all the material is thermally treated by heat radiating from the combustion
chamber
through the walls of the conveyor means. The organic material is preferably
mixed
inside the conveyor means for ensuring that the heat reaches all the material.
The
5 feeding means regulates the material flow to the conveyor means such that
the organic
material level inside the conveyor means is not too high or on the other hand
the level
is not too low. If there is too much material in the conveyor means there is a
risk that
all the material will not be treated thermally. If the material level is too
low there is a
risk that the material becomes over-carbonized. The regulation can also be
accomplished in the conveyor means such that the blades of the conveyor are in
different distances or the diameter of the conveyor means changes. One main
feature
of the conveyor means is that it rotates so that the organic material is
completely
mixed inside the conveyor means and the organic material is totally carbonized
during
the movement through the conveyor means so that there won't be any over-
carbonized material on the down side of the conveyor means and some raw
material
inside the material bedding. One possible conveyor means is a double screw
conveyor
where the screws work imbricated. The conveyor means has a shaft which is
mounted
on a bearing on both ends. The conveyor means is preferably supported by one
or
more supports, such as beams, so that the supports preferably are arranged to
go
through the combustion chamber in a cross direction of the combustion chamber,
i.e.
in a lateral direction of the combustion chamber.
The combustion chamber comprises one or more conveyor means, preferably
arranged parallel such that they all extend in a longitudinal direction
through the
combustion chamber. The combustion chamber also comprises at least one
combustion apparatus that produces heat to the combustion chamber. The
conveyor
means is preferably arranged to the upper part of the combustion chamber so
that the
flame coming from the combustion apparatus that is arranged preferably to the
lower
part of the combustion chamber is not touching the conveyor means. The flame
is
preferably directed to the longitudinal direction of the combustion chamber
toward the
opposite wall to which the combustion apparatus is pointed. The conveyor means
is
arranged air-tight so that the organic material is heated in an oxygen-free
space.
The combustion chamber is preferably a big box-like structure having
conveyor means going through the combustion chamber in the upper part of the
combustion chamber such that the conveyor means extend from the outside of the
combustion chamber through the combustion chamber and to the outside of the
combustion chamber. The conveyor means is preferably arranged to the
combustion
chamber in a longitudinal direction such that the conveyor means comes out
from the
combustion chamber in the opposite side of the combustion chamber than where
it
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goes in, i.e. the conveyor means ends in the opposite site of the combustion
chamber
than where it starts.
The combustion apparatus gets pyrolysis gas through the pipeline from the
conveyor means and an additional air from the combustion air blower. The
pyrolysis
gas and the additional air are mixed and burned inside the combustion
apparatus in
order to create a flame to the combustion chamber. The additional air creates
overpressure to the combustion chamber so that the combustion gases run out of
the
combustion chamber through a discharge outlet which is preferably in the upper
part
of the combustion chamber.
The combustion chamber is preferably isolated with a 200 - 250 mm thick
isolation layer. The apparatus, i.e. the carbonizer, is arranged to work in
overpressure.
An electric filter is arranged between the combustion chamber and the
discharge outlet so that the ash and smut particles can be removed from the
combustion gas so that tar and hydrocarbon aerosols can be recovered.
The apparatus of the invention can be used in many ways in order to get
different end products. One method for using the apparatus is to control the
amount of
organic material fed to the conveyor means by the feeding means for maximizing
the
separation of carbon from organic material configured to go through thermal
treatment. The feeding means is arranged to feed an optimum amount of organic
material depending on the process parameters, for example the time organic
material
is spending in the conveyor means or the temperature in which the thermal
treatment
is arranged to happen. The aim is to get all the organic material carbonized
during the
movement inside the conveyor means. Another method for using the apparatus is
that
the conveyor means is arranged to convey organic material in such a speed that
organic material is configured to be gasified for maximizing the amount of
pyrolysis
gas coming through the conveyor means. This means that the process time is
long and
the organic material moves preferably quite slowly in the conveyor means or
the
amount of organic material inside the conveyor means is small so that all the
organic
material is carbonized and even further at least partly gasified. The excess
gas can be
used in other purposes such as for burning in other apparatuses. Yet another
method
for using the apparatus is to create thermal energy in the combustion chamber
by
burning pyrolysis gas developed during thermal treatment and part of the
thermal
energy is transferred from the apparatus for example to heat spaces etc. Even
more
thermal energy than is needed can be created to develop pyrolysis gas.
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List of figures
In the following the invention will be described in more detail by referring
to
the figure, in which
Fig 1 shows an apparatus for thermally treating organic material in order to
separate carbon as of one preferred embodiment of the invention.
Detailed description of the invention
The figure 1 shows an example of the apparatus 1 for thermally treating
organic material in order to separate carbon from organic material. The
apparatus 1
comprises a combustion chamber 5 for thermal treatment of organic material and
the
combustion chamber 5 comprises a combustion apparatus 7 for heating said
combustion chamber 5. The apparatus also comprises conveyor means 3 for
conveying organic material during thermal treatment of organic material, said
conveyor means 3 extending through the combustion chamber 5 from the outside
of
the combustion chamber 5 and to the outside of the combustion chamber 5 and
the
conveyor means 3 is closed from the combustion chamber 5. The conveyor means 3
is
configured for distributing heat from the combustion chamber 5 to the organic
material such that the organic material is thermally treated. The conveyor
means 3 is
configured for conveying also pyrolysis gas developed during said thermal
treatment.
The pyrolysis gas is preferably arranged to move inside the conveyor means 3
as a
return flow toward feeding means 2. The apparatus comprises also feeding means
2
for receiving organic material and feeding said organic material to the
conveyor
means 3, said feeding means is arranged outside of the combustion chamber 5
and
removal means 4 for removing the thermally treated organic material from the
conveyor means 3. A pipeline 8 is arranged outside of the combustion chamber 5
for
conveying pyrolysis gas coming through the conveyor means 3 outside of the
combustion chamber 5 and from the conveyor means 3 through said pipeline 8 to
the
combustion apparatus 7 such that the pyrolysis gas cools down and is burned in
the
combustion apparatus 7 for creating heat inside the combustion chamber 5.
Pyrolysis
gas is configured to be conveyed by the pipeline 8 from the conveyor means 3
to the
combustion apparatus 7 via a separation arrangement 11 for separating tar from
pyrolysis gas. In other words, pyrolysis gas is processed by a separation
arrangement
11 for separating tar contained in the pyrolysis gas before pyrolysis gas is
burned in
the combustion chamber 5. The conveyor means 3 begins from the outside of the
combustion chamber 5 such that when the organic material arrives to the
conveyor
means 3 through feeding means 2 it does not immediately be exposed to thermal
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treatment. The conveyor means 3 is arranged to go through the combustion
chamber 5
such that during the travel in the area of the combustion chamber 5 the
organic
material is thermally treated inside the conveyor means 3. On the other end of
the
conveyor means 3 the thermally treated organic material is removed from the
conveyor means 3 through removal means 4. While the organic material is
thermally
treated the pyrolysis gas is developed inside the conveyor means 3 and it
moves as a
return flow inside the conveyor means 3 toward the beginning of the conveyor
means
3. A pipeline 8 is arranged in flow communication between the conveyor means 3
and
the combustion apparatus 7 such that the pyrolysis gas coming from the
conveyor
means 3 is moved along the pipeline 8 to the combustion apparatus 7 where it
is
burned in order to create a flame inside the combustion chamber 5 to heat the
combustion chamber 5 and radiate heat to the conveyor means 3 for thermally
treating
organic material conveyed inside the conveyor means 3. The combustion gas is
lead
to a discharge outlet 6. The combustion apparatus 7 is arranged to create a
flame
inside the combustion chamber 5 such that it heats the walls of the combustion
chamber 5 and radiates heat to the conveyor means 3. The pyrolysis gas is
continuously during thermal treatment conveyed from the conveyor means 3 to
the
combustion apparatus 7 through the pipeline 8. The apparatus 1 according to
the
invention works in overpressure. The conveyor means 3 is preferably supported
by
one or more supports 9 going through the combustion chamber 5 in a lateral
direction
of the combustion chamber 5. The conveyor means 3 comprises preferably a shaft
and
pyrolysis gas is arranged to move inside the conveyor means 3 near the shaft
and/or
near the upper part of the conveyor means 3. The combustion chamber 5 is
preferably
arranged in a box-like structure 10.
It is apparent to a person skilled in the art that as technology advanced, the
basic idea of the invention can be implemented in various ways. The invention
and its
embodiments are therefore not restricted to the above examples, but they may
vary
within the scope of the claims.
